diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14 #include "userdiff.h"
  15 #include "sigchain.h"
  16 #include "submodule.h"
  17 #include "ll-merge.h"
  18
  19 #ifdef NO_FAST_WORKING_DIRECTORY
  20 #define FAST_WORKING_DIRECTORY 0
  21 #else
  22 #define FAST_WORKING_DIRECTORY 1
  23 #endif
  24
  25 static int diff_detect_rename_default;
  26 static int diff_rename_limit_default = 400;
  27 static int diff_suppress_blank_empty;
  28 int diff_use_color_default = -1;
  29 static const char *diff_word_regex_cfg;
  30 static const char *external_diff_cmd_cfg;
  31 int diff_auto_refresh_index = 1;
  32 static int diff_mnemonic_prefix;
  33 static int diff_no_prefix;
  34 static int diff_dirstat_permille_default = 30;
  35 static struct diff_options default_diff_options;
  36
  37 static char diff_colors[][COLOR_MAXLEN] = {
  38         GIT_COLOR_RESET,
  39         GIT_COLOR_NORMAL,       /* PLAIN */
  40         GIT_COLOR_BOLD,         /* METAINFO */
  41         GIT_COLOR_CYAN,         /* FRAGINFO */
  42         GIT_COLOR_RED,          /* OLD */
  43         GIT_COLOR_GREEN,        /* NEW */
  44         GIT_COLOR_YELLOW,       /* COMMIT */
  45         GIT_COLOR_BG_RED,       /* WHITESPACE */
  46         GIT_COLOR_NORMAL,       /* FUNCINFO */
  47 };
  48
  49 static int parse_diff_color_slot(const char *var, int ofs)
  50 {
  51         if (!strcasecmp(var+ofs, "plain"))
  52                 return DIFF_PLAIN;
  53         if (!strcasecmp(var+ofs, "meta"))
  54                 return DIFF_METAINFO;
  55         if (!strcasecmp(var+ofs, "frag"))
  56                 return DIFF_FRAGINFO;
  57         if (!strcasecmp(var+ofs, "old"))
  58                 return DIFF_FILE_OLD;
  59         if (!strcasecmp(var+ofs, "new"))
  60                 return DIFF_FILE_NEW;
  61         if (!strcasecmp(var+ofs, "commit"))
  62                 return DIFF_COMMIT;
  63         if (!strcasecmp(var+ofs, "whitespace"))
  64                 return DIFF_WHITESPACE;
  65         if (!strcasecmp(var+ofs, "func"))
  66                 return DIFF_FUNCINFO;
  67         return -1;
  68 }
  69
  70 static int parse_dirstat_params(struct diff_options *options, const char *params,
  71                                 struct strbuf *errmsg)
  72 {
  73         const char *p = params;
  74         int p_len, ret = 0;
  75
  76         while (*p) {
  77                 p_len = strchrnul(p, ',') - p;
  78                 if (!memcmp(p, "changes", p_len)) {
  79                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  80                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  81                 } else if (!memcmp(p, "lines", p_len)) {
  82                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  83                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  84                 } else if (!memcmp(p, "files", p_len)) {
  85                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  86                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  87                 } else if (!memcmp(p, "noncumulative", p_len)) {
  88                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  89                 } else if (!memcmp(p, "cumulative", p_len)) {
  90                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  91                 } else if (isdigit(*p)) {
  92                         char *end;
  93                         int permille = strtoul(p, &end, 10) * 10;
  94                         if (*end == '.' && isdigit(*++end)) {
  95                                 /* only use first digit */
  96                                 permille += *end - '0';
  97                                 /* .. and ignore any further digits */
  98                                 while (isdigit(*++end))
  99                                         ; /* nothing */
 100                         }
 101                         if (end - p == p_len)
 102                                 options->dirstat_permille = permille;
 103                         else {
 104                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%.*s'\n"),
 105                                             p_len, p);
 106                                 ret++;
 107                         }
 108                 } else {
 109                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%.*s'\n"),
 110                                     p_len, p);
 111                         ret++;
 112                 }
 113
 114                 p += p_len;
 115
 116                 if (*p)
 117                         p++; /* more parameters, swallow separator */
 118         }
 119         return ret;
 120 }
 121
 122 static int git_config_rename(const char *var, const char *value)
 123 {
 124         if (!value)
 125                 return DIFF_DETECT_RENAME;
 126         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 127                 return  DIFF_DETECT_COPY;
 128         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 129 }
 130
 131 /*
 132  * These are to give UI layer defaults.
 133  * The core-level commands such as git-diff-files should
 134  * never be affected by the setting of diff.renames
 135  * the user happens to have in the configuration file.
 136  */
 137 int git_diff_ui_config(const char *var, const char *value, void *cb)
 138 {
 139         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 140                 diff_use_color_default = git_config_colorbool(var, value);
 141                 return 0;
 142         }
 143         if (!strcmp(var, "diff.renames")) {
 144                 diff_detect_rename_default = git_config_rename(var, value);
 145                 return 0;
 146         }
 147         if (!strcmp(var, "diff.autorefreshindex")) {
 148                 diff_auto_refresh_index = git_config_bool(var, value);
 149                 return 0;
 150         }
 151         if (!strcmp(var, "diff.mnemonicprefix")) {
 152                 diff_mnemonic_prefix = git_config_bool(var, value);
 153                 return 0;
 154         }
 155         if (!strcmp(var, "diff.noprefix")) {
 156                 diff_no_prefix = git_config_bool(var, value);
 157                 return 0;
 158         }
 159         if (!strcmp(var, "diff.external"))
 160                 return git_config_string(&external_diff_cmd_cfg, var, value);
 161         if (!strcmp(var, "diff.wordregex"))
 162                 return git_config_string(&diff_word_regex_cfg, var, value);
 163
 164         if (!strcmp(var, "diff.ignoresubmodules"))
 165                 handle_ignore_submodules_arg(&default_diff_options, value);
 166
 167         if (git_color_config(var, value, cb) < 0)
 168                 return -1;
 169
 170         return git_diff_basic_config(var, value, cb);
 171 }
 172
 173 int git_diff_basic_config(const char *var, const char *value, void *cb)
 174 {
 175         if (!strcmp(var, "diff.renamelimit")) {
 176                 diff_rename_limit_default = git_config_int(var, value);
 177                 return 0;
 178         }
 179
 180         switch (userdiff_config(var, value)) {
 181                 case 0: break;
 182                 case -1: return -1;
 183                 default: return 0;
 184         }
 185
 186         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 187                 int slot = parse_diff_color_slot(var, 11);
 188                 if (slot < 0)
 189                         return 0;
 190                 if (!value)
 191                         return config_error_nonbool(var);
 192                 color_parse(value, var, diff_colors[slot]);
 193                 return 0;
 194         }
 195
 196         /* like GNU diff's --suppress-blank-empty option  */
 197         if (!strcmp(var, "diff.suppressblankempty") ||
 198                         /* for backwards compatibility */
 199                         !strcmp(var, "diff.suppress-blank-empty")) {
 200                 diff_suppress_blank_empty = git_config_bool(var, value);
 201                 return 0;
 202         }
 203
 204         if (!strcmp(var, "diff.dirstat")) {
 205                 struct strbuf errmsg = STRBUF_INIT;
 206                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 207                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 208                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 209                                 errmsg.buf);
 210                 strbuf_release(&errmsg);
 211                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 212                 return 0;
 213         }
 214
 215         if (!prefixcmp(var, "submodule."))
 216                 return parse_submodule_config_option(var, value);
 217
 218         return git_default_config(var, value, cb);
 219 }
 220
 221 static char *quote_two(const char *one, const char *two)
 222 {
 223         int need_one = quote_c_style(one, NULL, NULL, 1);
 224         int need_two = quote_c_style(two, NULL, NULL, 1);
 225         struct strbuf res = STRBUF_INIT;
 226
 227         if (need_one + need_two) {
 228                 strbuf_addch(&res, '"');
 229                 quote_c_style(one, &res, NULL, 1);
 230                 quote_c_style(two, &res, NULL, 1);
 231                 strbuf_addch(&res, '"');
 232         } else {
 233                 strbuf_addstr(&res, one);
 234                 strbuf_addstr(&res, two);
 235         }
 236         return strbuf_detach(&res, NULL);
 237 }
 238
 239 static const char *external_diff(void)
 240 {
 241         static const char *external_diff_cmd = NULL;
 242         static int done_preparing = 0;
 243
 244         if (done_preparing)
 245                 return external_diff_cmd;
 246         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 247         if (!external_diff_cmd)
 248                 external_diff_cmd = external_diff_cmd_cfg;
 249         done_preparing = 1;
 250         return external_diff_cmd;
 251 }
 252
 253 static struct diff_tempfile {
 254         const char *name; /* filename external diff should read from */
 255         char hex[41];
 256         char mode[10];
 257         char tmp_path[PATH_MAX];
 258 } diff_temp[2];
 259
 260 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 261
 262 struct emit_callback {
 263         int color_diff;
 264         unsigned ws_rule;
 265         int blank_at_eof_in_preimage;
 266         int blank_at_eof_in_postimage;
 267         int lno_in_preimage;
 268         int lno_in_postimage;
 269         sane_truncate_fn truncate;
 270         const char **label_path;
 271         struct diff_words_data *diff_words;
 272         struct diff_options *opt;
 273         int *found_changesp;
 274         struct strbuf *header;
 275 };
 276
 277 static int count_lines(const char *data, int size)
 278 {
 279         int count, ch, completely_empty = 1, nl_just_seen = 0;
 280         count = 0;
 281         while (0 < size--) {
 282                 ch = *data++;
 283                 if (ch == '\n') {
 284                         count++;
 285                         nl_just_seen = 1;
 286                         completely_empty = 0;
 287                 }
 288                 else {
 289                         nl_just_seen = 0;
 290                         completely_empty = 0;
 291                 }
 292         }
 293         if (completely_empty)
 294                 return 0;
 295         if (!nl_just_seen)
 296                 count++; /* no trailing newline */
 297         return count;
 298 }
 299
 300 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 301 {
 302         if (!DIFF_FILE_VALID(one)) {
 303                 mf->ptr = (char *)""; /* does not matter */
 304                 mf->size = 0;
 305                 return 0;
 306         }
 307         else if (diff_populate_filespec(one, 0))
 308                 return -1;
 309
 310         mf->ptr = one->data;
 311         mf->size = one->size;
 312         return 0;
 313 }
 314
 315 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 316 static unsigned long diff_filespec_size(struct diff_filespec *one)
 317 {
 318         if (!DIFF_FILE_VALID(one))
 319                 return 0;
 320         diff_populate_filespec(one, 1);
 321         return one->size;
 322 }
 323
 324 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 325 {
 326         char *ptr = mf->ptr;
 327         long size = mf->size;
 328         int cnt = 0;
 329
 330         if (!size)
 331                 return cnt;
 332         ptr += size - 1; /* pointing at the very end */
 333         if (*ptr != '\n')
 334                 ; /* incomplete line */
 335         else
 336                 ptr--; /* skip the last LF */
 337         while (mf->ptr < ptr) {
 338                 char *prev_eol;
 339                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 340                         if (*prev_eol == '\n')
 341                                 break;
 342                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 343                         break;
 344                 cnt++;
 345                 ptr = prev_eol - 1;
 346         }
 347         return cnt;
 348 }
 349
 350 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 351                                struct emit_callback *ecbdata)
 352 {
 353         int l1, l2, at;
 354         unsigned ws_rule = ecbdata->ws_rule;
 355         l1 = count_trailing_blank(mf1, ws_rule);
 356         l2 = count_trailing_blank(mf2, ws_rule);
 357         if (l2 <= l1) {
 358                 ecbdata->blank_at_eof_in_preimage = 0;
 359                 ecbdata->blank_at_eof_in_postimage = 0;
 360                 return;
 361         }
 362         at = count_lines(mf1->ptr, mf1->size);
 363         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 364
 365         at = count_lines(mf2->ptr, mf2->size);
 366         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 367 }
 368
 369 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 370                         int first, const char *line, int len)
 371 {
 372         int has_trailing_newline, has_trailing_carriage_return;
 373         int nofirst;
 374         FILE *file = o->file;
 375
 376         if (o->output_prefix) {
 377                 struct strbuf *msg = NULL;
 378                 msg = o->output_prefix(o, o->output_prefix_data);
 379                 assert(msg);
 380                 fwrite(msg->buf, msg->len, 1, file);
 381         }
 382
 383         if (len == 0) {
 384                 has_trailing_newline = (first == '\n');
 385                 has_trailing_carriage_return = (!has_trailing_newline &&
 386                                                 (first == '\r'));
 387                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 388         } else {
 389                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 390                 if (has_trailing_newline)
 391                         len--;
 392                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 393                 if (has_trailing_carriage_return)
 394                         len--;
 395                 nofirst = 0;
 396         }
 397
 398         if (len || !nofirst) {
 399                 fputs(set, file);
 400                 if (!nofirst)
 401                         fputc(first, file);
 402                 fwrite(line, len, 1, file);
 403                 fputs(reset, file);
 404         }
 405         if (has_trailing_carriage_return)
 406                 fputc('\r', file);
 407         if (has_trailing_newline)
 408                 fputc('\n', file);
 409 }
 410
 411 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 412                       const char *line, int len)
 413 {
 414         emit_line_0(o, set, reset, line[0], line+1, len-1);
 415 }
 416
 417 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 418 {
 419         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 420               ecbdata->blank_at_eof_in_preimage &&
 421               ecbdata->blank_at_eof_in_postimage &&
 422               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 423               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 424                 return 0;
 425         return ws_blank_line(line, len, ecbdata->ws_rule);
 426 }
 427
 428 static void emit_add_line(const char *reset,
 429                           struct emit_callback *ecbdata,
 430                           const char *line, int len)
 431 {
 432         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 433         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 434
 435         if (!*ws)
 436                 emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 437         else if (new_blank_line_at_eof(ecbdata, line, len))
 438                 /* Blank line at EOF - paint '+' as well */
 439                 emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 440         else {
 441                 /* Emit just the prefix, then the rest. */
 442                 emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 443                 ws_check_emit(line, len, ecbdata->ws_rule,
 444                               ecbdata->opt->file, set, reset, ws);
 445         }
 446 }
 447
 448 static void emit_hunk_header(struct emit_callback *ecbdata,
 449                              const char *line, int len)
 450 {
 451         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 452         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 453         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 454         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 455         static const char atat[2] = { '@', '@' };
 456         const char *cp, *ep;
 457         struct strbuf msgbuf = STRBUF_INIT;
 458         int org_len = len;
 459         int i = 1;
 460
 461         /*
 462          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 463          * it always is at least 10 bytes long.
 464          */
 465         if (len < 10 ||
 466             memcmp(line, atat, 2) ||
 467             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 468                 emit_line(ecbdata->opt, plain, reset, line, len);
 469                 return;
 470         }
 471         ep += 2; /* skip over @@ */
 472
 473         /* The hunk header in fraginfo color */
 474         strbuf_add(&msgbuf, frag, strlen(frag));
 475         strbuf_add(&msgbuf, line, ep - line);
 476         strbuf_add(&msgbuf, reset, strlen(reset));
 477
 478         /*
 479          * trailing "\r\n"
 480          */
 481         for ( ; i < 3; i++)
 482                 if (line[len - i] == '\r' || line[len - i] == '\n')
 483                         len--;
 484
 485         /* blank before the func header */
 486         for (cp = ep; ep - line < len; ep++)
 487                 if (*ep != ' ' && *ep != '\t')
 488                         break;
 489         if (ep != cp) {
 490                 strbuf_add(&msgbuf, plain, strlen(plain));
 491                 strbuf_add(&msgbuf, cp, ep - cp);
 492                 strbuf_add(&msgbuf, reset, strlen(reset));
 493         }
 494
 495         if (ep < line + len) {
 496                 strbuf_add(&msgbuf, func, strlen(func));
 497                 strbuf_add(&msgbuf, ep, line + len - ep);
 498                 strbuf_add(&msgbuf, reset, strlen(reset));
 499         }
 500
 501         strbuf_add(&msgbuf, line + len, org_len - len);
 502         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 503         strbuf_release(&msgbuf);
 504 }
 505
 506 static struct diff_tempfile *claim_diff_tempfile(void) {
 507         int i;
 508         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 509                 if (!diff_temp[i].name)
 510                         return diff_temp + i;
 511         die("BUG: diff is failing to clean up its tempfiles");
 512 }
 513
 514 static int remove_tempfile_installed;
 515
 516 static void remove_tempfile(void)
 517 {
 518         int i;
 519         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 520                 if (diff_temp[i].name == diff_temp[i].tmp_path)
 521                         unlink_or_warn(diff_temp[i].name);
 522                 diff_temp[i].name = NULL;
 523         }
 524 }
 525
 526 static void remove_tempfile_on_signal(int signo)
 527 {
 528         remove_tempfile();
 529         sigchain_pop(signo);
 530         raise(signo);
 531 }
 532
 533 static void print_line_count(FILE *file, int count)
 534 {
 535         switch (count) {
 536         case 0:
 537                 fprintf(file, "0,0");
 538                 break;
 539         case 1:
 540                 fprintf(file, "1");
 541                 break;
 542         default:
 543                 fprintf(file, "1,%d", count);
 544                 break;
 545         }
 546 }
 547
 548 static void emit_rewrite_lines(struct emit_callback *ecb,
 549                                int prefix, const char *data, int size)
 550 {
 551         const char *endp = NULL;
 552         static const char *nneof = " No newline at end of file\n";
 553         const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 554         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 555
 556         while (0 < size) {
 557                 int len;
 558
 559                 endp = memchr(data, '\n', size);
 560                 len = endp ? (endp - data + 1) : size;
 561                 if (prefix != '+') {
 562                         ecb->lno_in_preimage++;
 563                         emit_line_0(ecb->opt, old, reset, '-',
 564                                     data, len);
 565                 } else {
 566                         ecb->lno_in_postimage++;
 567                         emit_add_line(reset, ecb, data, len);
 568                 }
 569                 size -= len;
 570                 data += len;
 571         }
 572         if (!endp) {
 573                 const char *plain = diff_get_color(ecb->color_diff,
 574                                                    DIFF_PLAIN);
 575                 emit_line_0(ecb->opt, plain, reset, '\\',
 576                             nneof, strlen(nneof));
 577         }
 578 }
 579
 580 static void emit_rewrite_diff(const char *name_a,
 581                               const char *name_b,
 582                               struct diff_filespec *one,
 583                               struct diff_filespec *two,
 584                               struct userdiff_driver *textconv_one,
 585                               struct userdiff_driver *textconv_two,
 586                               struct diff_options *o)
 587 {
 588         int lc_a, lc_b;
 589         const char *name_a_tab, *name_b_tab;
 590         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 591         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 592         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 593         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 594         const char *a_prefix, *b_prefix;
 595         char *data_one, *data_two;
 596         size_t size_one, size_two;
 597         struct emit_callback ecbdata;
 598         char *line_prefix = "";
 599         struct strbuf *msgbuf;
 600
 601         if (o && o->output_prefix) {
 602                 msgbuf = o->output_prefix(o, o->output_prefix_data);
 603                 line_prefix = msgbuf->buf;
 604         }
 605
 606         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 607                 a_prefix = o->b_prefix;
 608                 b_prefix = o->a_prefix;
 609         } else {
 610                 a_prefix = o->a_prefix;
 611                 b_prefix = o->b_prefix;
 612         }
 613
 614         name_a += (*name_a == '/');
 615         name_b += (*name_b == '/');
 616         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 617         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 618
 619         strbuf_reset(&a_name);
 620         strbuf_reset(&b_name);
 621         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 622         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 623
 624         size_one = fill_textconv(textconv_one, one, &data_one);
 625         size_two = fill_textconv(textconv_two, two, &data_two);
 626
 627         memset(&ecbdata, 0, sizeof(ecbdata));
 628         ecbdata.color_diff = want_color(o->use_color);
 629         ecbdata.found_changesp = &o->found_changes;
 630         ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 631         ecbdata.opt = o;
 632         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 633                 mmfile_t mf1, mf2;
 634                 mf1.ptr = (char *)data_one;
 635                 mf2.ptr = (char *)data_two;
 636                 mf1.size = size_one;
 637                 mf2.size = size_two;
 638                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 639         }
 640         ecbdata.lno_in_preimage = 1;
 641         ecbdata.lno_in_postimage = 1;
 642
 643         lc_a = count_lines(data_one, size_one);
 644         lc_b = count_lines(data_two, size_two);
 645         fprintf(o->file,
 646                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 647                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 648                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 649                 line_prefix, fraginfo);
 650         if (!o->irreversible_delete)
 651                 print_line_count(o->file, lc_a);
 652         else
 653                 fprintf(o->file, "?,?");
 654         fprintf(o->file, " +");
 655         print_line_count(o->file, lc_b);
 656         fprintf(o->file, " @@%s\n", reset);
 657         if (lc_a && !o->irreversible_delete)
 658                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 659         if (lc_b)
 660                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 661         if (textconv_one)
 662                 free((char *)data_one);
 663         if (textconv_two)
 664                 free((char *)data_two);
 665 }
 666
 667 struct diff_words_buffer {
 668         mmfile_t text;
 669         long alloc;
 670         struct diff_words_orig {
 671                 const char *begin, *end;
 672         } *orig;
 673         int orig_nr, orig_alloc;
 674 };
 675
 676 static void diff_words_append(char *line, unsigned long len,
 677                 struct diff_words_buffer *buffer)
 678 {
 679         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 680         line++;
 681         len--;
 682         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 683         buffer->text.size += len;
 684         buffer->text.ptr[buffer->text.size] = '\0';
 685 }
 686
 687 struct diff_words_style_elem {
 688         const char *prefix;
 689         const char *suffix;
 690         const char *color; /* NULL; filled in by the setup code if
 691                             * color is enabled */
 692 };
 693
 694 struct diff_words_style {
 695         enum diff_words_type type;
 696         struct diff_words_style_elem new, old, ctx;
 697         const char *newline;
 698 };
 699
 700 static struct diff_words_style diff_words_styles[] = {
 701         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 702         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 703         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 704 };
 705
 706 struct diff_words_data {
 707         struct diff_words_buffer minus, plus;
 708         const char *current_plus;
 709         int last_minus;
 710         struct diff_options *opt;
 711         regex_t *word_regex;
 712         enum diff_words_type type;
 713         struct diff_words_style *style;
 714 };
 715
 716 static int fn_out_diff_words_write_helper(FILE *fp,
 717                                           struct diff_words_style_elem *st_el,
 718                                           const char *newline,
 719                                           size_t count, const char *buf,
 720                                           const char *line_prefix)
 721 {
 722         int print = 0;
 723
 724         while (count) {
 725                 char *p = memchr(buf, '\n', count);
 726                 if (print)
 727                         fputs(line_prefix, fp);
 728                 if (p != buf) {
 729                         if (st_el->color && fputs(st_el->color, fp) < 0)
 730                                 return -1;
 731                         if (fputs(st_el->prefix, fp) < 0 ||
 732                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 733                             fputs(st_el->suffix, fp) < 0)
 734                                 return -1;
 735                         if (st_el->color && *st_el->color
 736                             && fputs(GIT_COLOR_RESET, fp) < 0)
 737                                 return -1;
 738                 }
 739                 if (!p)
 740                         return 0;
 741                 if (fputs(newline, fp) < 0)
 742                         return -1;
 743                 count -= p + 1 - buf;
 744                 buf = p + 1;
 745                 print = 1;
 746         }
 747         return 0;
 748 }
 749
 750 /*
 751  * '--color-words' algorithm can be described as:
 752  *
 753  *   1. collect a the minus/plus lines of a diff hunk, divided into
 754  *      minus-lines and plus-lines;
 755  *
 756  *   2. break both minus-lines and plus-lines into words and
 757  *      place them into two mmfile_t with one word for each line;
 758  *
 759  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 760  *
 761  * And for the common parts of the both file, we output the plus side text.
 762  * diff_words->current_plus is used to trace the current position of the plus file
 763  * which printed. diff_words->last_minus is used to trace the last minus word
 764  * printed.
 765  *
 766  * For '--graph' to work with '--color-words', we need to output the graph prefix
 767  * on each line of color words output. Generally, there are two conditions on
 768  * which we should output the prefix.
 769  *
 770  *   1. diff_words->last_minus == 0 &&
 771  *      diff_words->current_plus == diff_words->plus.text.ptr
 772  *
 773  *      that is: the plus text must start as a new line, and if there is no minus
 774  *      word printed, a graph prefix must be printed.
 775  *
 776  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 777  *      *(diff_words->current_plus - 1) == '\n'
 778  *
 779  *      that is: a graph prefix must be printed following a '\n'
 780  */
 781 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 782 {
 783         if ((diff_words->last_minus == 0 &&
 784                 diff_words->current_plus == diff_words->plus.text.ptr) ||
 785                 (diff_words->current_plus > diff_words->plus.text.ptr &&
 786                 *(diff_words->current_plus - 1) == '\n')) {
 787                 return 1;
 788         } else {
 789                 return 0;
 790         }
 791 }
 792
 793 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 794 {
 795         struct diff_words_data *diff_words = priv;
 796         struct diff_words_style *style = diff_words->style;
 797         int minus_first, minus_len, plus_first, plus_len;
 798         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 799         struct diff_options *opt = diff_words->opt;
 800         struct strbuf *msgbuf;
 801         char *line_prefix = "";
 802
 803         if (line[0] != '@' || parse_hunk_header(line, len,
 804                         &minus_first, &minus_len, &plus_first, &plus_len))
 805                 return;
 806
 807         assert(opt);
 808         if (opt->output_prefix) {
 809                 msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 810                 line_prefix = msgbuf->buf;
 811         }
 812
 813         /* POSIX requires that first be decremented by one if len == 0... */
 814         if (minus_len) {
 815                 minus_begin = diff_words->minus.orig[minus_first].begin;
 816                 minus_end =
 817                         diff_words->minus.orig[minus_first + minus_len - 1].end;
 818         } else
 819                 minus_begin = minus_end =
 820                         diff_words->minus.orig[minus_first].end;
 821
 822         if (plus_len) {
 823                 plus_begin = diff_words->plus.orig[plus_first].begin;
 824                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 825         } else
 826                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 827
 828         if (color_words_output_graph_prefix(diff_words)) {
 829                 fputs(line_prefix, diff_words->opt->file);
 830         }
 831         if (diff_words->current_plus != plus_begin) {
 832                 fn_out_diff_words_write_helper(diff_words->opt->file,
 833                                 &style->ctx, style->newline,
 834                                 plus_begin - diff_words->current_plus,
 835                                 diff_words->current_plus, line_prefix);
 836                 if (*(plus_begin - 1) == '\n')
 837                         fputs(line_prefix, diff_words->opt->file);
 838         }
 839         if (minus_begin != minus_end) {
 840                 fn_out_diff_words_write_helper(diff_words->opt->file,
 841                                 &style->old, style->newline,
 842                                 minus_end - minus_begin, minus_begin,
 843                                 line_prefix);
 844         }
 845         if (plus_begin != plus_end) {
 846                 fn_out_diff_words_write_helper(diff_words->opt->file,
 847                                 &style->new, style->newline,
 848                                 plus_end - plus_begin, plus_begin,
 849                                 line_prefix);
 850         }
 851
 852         diff_words->current_plus = plus_end;
 853         diff_words->last_minus = minus_first;
 854 }
 855
 856 /* This function starts looking at *begin, and returns 0 iff a word was found. */
 857 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 858                 int *begin, int *end)
 859 {
 860         if (word_regex && *begin < buffer->size) {
 861                 regmatch_t match[1];
 862                 if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 863                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 864                                         '\n', match[0].rm_eo - match[0].rm_so);
 865                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 866                         *begin += match[0].rm_so;
 867                         return *begin >= *end;
 868                 }
 869                 return -1;
 870         }
 871
 872         /* find the next word */
 873         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 874                 (*begin)++;
 875         if (*begin >= buffer->size)
 876                 return -1;
 877
 878         /* find the end of the word */
 879         *end = *begin + 1;
 880         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 881                 (*end)++;
 882
 883         return 0;
 884 }
 885
 886 /*
 887  * This function splits the words in buffer->text, stores the list with
 888  * newline separator into out, and saves the offsets of the original words
 889  * in buffer->orig.
 890  */
 891 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 892                 regex_t *word_regex)
 893 {
 894         int i, j;
 895         long alloc = 0;
 896
 897         out->size = 0;
 898         out->ptr = NULL;
 899
 900         /* fake an empty "0th" word */
 901         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 902         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 903         buffer->orig_nr = 1;
 904
 905         for (i = 0; i < buffer->text.size; i++) {
 906                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 907                         return;
 908
 909                 /* store original boundaries */
 910                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 911                                 buffer->orig_alloc);
 912                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 913                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 914                 buffer->orig_nr++;
 915
 916                 /* store one word */
 917                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 918                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 919                 out->ptr[out->size + j - i] = '\n';
 920                 out->size += j - i + 1;
 921
 922                 i = j - 1;
 923         }
 924 }
 925
 926 /* this executes the word diff on the accumulated buffers */
 927 static void diff_words_show(struct diff_words_data *diff_words)
 928 {
 929         xpparam_t xpp;
 930         xdemitconf_t xecfg;
 931         mmfile_t minus, plus;
 932         struct diff_words_style *style = diff_words->style;
 933
 934         struct diff_options *opt = diff_words->opt;
 935         struct strbuf *msgbuf;
 936         char *line_prefix = "";
 937
 938         assert(opt);
 939         if (opt->output_prefix) {
 940                 msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 941                 line_prefix = msgbuf->buf;
 942         }
 943
 944         /* special case: only removal */
 945         if (!diff_words->plus.text.size) {
 946                 fputs(line_prefix, diff_words->opt->file);
 947                 fn_out_diff_words_write_helper(diff_words->opt->file,
 948                         &style->old, style->newline,
 949                         diff_words->minus.text.size,
 950                         diff_words->minus.text.ptr, line_prefix);
 951                 diff_words->minus.text.size = 0;
 952                 return;
 953         }
 954
 955         diff_words->current_plus = diff_words->plus.text.ptr;
 956         diff_words->last_minus = 0;
 957
 958         memset(&xpp, 0, sizeof(xpp));
 959         memset(&xecfg, 0, sizeof(xecfg));
 960         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 961         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 962         xpp.flags = 0;
 963         /* as only the hunk header will be parsed, we need a 0-context */
 964         xecfg.ctxlen = 0;
 965         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 966                       &xpp, &xecfg);
 967         free(minus.ptr);
 968         free(plus.ptr);
 969         if (diff_words->current_plus != diff_words->plus.text.ptr +
 970                         diff_words->plus.text.size) {
 971                 if (color_words_output_graph_prefix(diff_words))
 972                         fputs(line_prefix, diff_words->opt->file);
 973                 fn_out_diff_words_write_helper(diff_words->opt->file,
 974                         &style->ctx, style->newline,
 975                         diff_words->plus.text.ptr + diff_words->plus.text.size
 976                         - diff_words->current_plus, diff_words->current_plus,
 977                         line_prefix);
 978         }
 979         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 980 }
 981
 982 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
 983 static void diff_words_flush(struct emit_callback *ecbdata)
 984 {
 985         if (ecbdata->diff_words->minus.text.size ||
 986             ecbdata->diff_words->plus.text.size)
 987                 diff_words_show(ecbdata->diff_words);
 988 }
 989
 990 static void free_diff_words_data(struct emit_callback *ecbdata)
 991 {
 992         if (ecbdata->diff_words) {
 993                 diff_words_flush(ecbdata);
 994                 free (ecbdata->diff_words->minus.text.ptr);
 995                 free (ecbdata->diff_words->minus.orig);
 996                 free (ecbdata->diff_words->plus.text.ptr);
 997                 free (ecbdata->diff_words->plus.orig);
 998                 if (ecbdata->diff_words->word_regex) {
 999                         regfree(ecbdata->diff_words->word_regex);
1000                         free(ecbdata->diff_words->word_regex);
1001                 }
1002                 free(ecbdata->diff_words);
1003                 ecbdata->diff_words = NULL;
1004         }
1005 }
1006
1007 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1008 {
1009         if (want_color(diff_use_color))
1010                 return diff_colors[ix];
1011         return "";
1012 }
1013
1014 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1015 {
1016         const char *cp;
1017         unsigned long allot;
1018         size_t l = len;
1019
1020         if (ecb->truncate)
1021                 return ecb->truncate(line, len);
1022         cp = line;
1023         allot = l;
1024         while (0 < l) {
1025                 (void) utf8_width(&cp, &l);
1026                 if (!cp)
1027                         break; /* truncated in the middle? */
1028         }
1029         return allot - l;
1030 }
1031
1032 static void find_lno(const char *line, struct emit_callback *ecbdata)
1033 {
1034         const char *p;
1035         ecbdata->lno_in_preimage = 0;
1036         ecbdata->lno_in_postimage = 0;
1037         p = strchr(line, '-');
1038         if (!p)
1039                 return; /* cannot happen */
1040         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1041         p = strchr(p, '+');
1042         if (!p)
1043                 return; /* cannot happen */
1044         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1045 }
1046
1047 static void fn_out_consume(void *priv, char *line, unsigned long len)
1048 {
1049         struct emit_callback *ecbdata = priv;
1050         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1051         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1052         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1053         struct diff_options *o = ecbdata->opt;
1054         char *line_prefix = "";
1055         struct strbuf *msgbuf;
1056
1057         if (o && o->output_prefix) {
1058                 msgbuf = o->output_prefix(o, o->output_prefix_data);
1059                 line_prefix = msgbuf->buf;
1060         }
1061
1062         if (ecbdata->header) {
1063                 fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1064                 strbuf_reset(ecbdata->header);
1065                 ecbdata->header = NULL;
1066         }
1067         *(ecbdata->found_changesp) = 1;
1068
1069         if (ecbdata->label_path[0]) {
1070                 const char *name_a_tab, *name_b_tab;
1071
1072                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1073                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1074
1075                 fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1076                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1077                 fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1078                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1079                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1080         }
1081
1082         if (diff_suppress_blank_empty
1083             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1084                 line[0] = '\n';
1085                 len = 1;
1086         }
1087
1088         if (line[0] == '@') {
1089                 if (ecbdata->diff_words)
1090                         diff_words_flush(ecbdata);
1091                 len = sane_truncate_line(ecbdata, line, len);
1092                 find_lno(line, ecbdata);
1093                 emit_hunk_header(ecbdata, line, len);
1094                 if (line[len-1] != '\n')
1095                         putc('\n', ecbdata->opt->file);
1096                 return;
1097         }
1098
1099         if (len < 1) {
1100                 emit_line(ecbdata->opt, reset, reset, line, len);
1101                 if (ecbdata->diff_words
1102                     && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1103                         fputs("~\n", ecbdata->opt->file);
1104                 return;
1105         }
1106
1107         if (ecbdata->diff_words) {
1108                 if (line[0] == '-') {
1109                         diff_words_append(line, len,
1110                                           &ecbdata->diff_words->minus);
1111                         return;
1112                 } else if (line[0] == '+') {
1113                         diff_words_append(line, len,
1114                                           &ecbdata->diff_words->plus);
1115                         return;
1116                 } else if (!prefixcmp(line, "\\ ")) {
1117                         /*
1118                          * Eat the "no newline at eof" marker as if we
1119                          * saw a "+" or "-" line with nothing on it,
1120                          * and return without diff_words_flush() to
1121                          * defer processing. If this is the end of
1122                          * preimage, more "+" lines may come after it.
1123                          */
1124                         return;
1125                 }
1126                 diff_words_flush(ecbdata);
1127                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1128                         emit_line(ecbdata->opt, plain, reset, line, len);
1129                         fputs("~\n", ecbdata->opt->file);
1130                 } else {
1131                         /*
1132                          * Skip the prefix character, if any.  With
1133                          * diff_suppress_blank_empty, there may be
1134                          * none.
1135                          */
1136                         if (line[0] != '\n') {
1137                               line++;
1138                               len--;
1139                         }
1140                         emit_line(ecbdata->opt, plain, reset, line, len);
1141                 }
1142                 return;
1143         }
1144
1145         if (line[0] != '+') {
1146                 const char *color =
1147                         diff_get_color(ecbdata->color_diff,
1148                                        line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1149                 ecbdata->lno_in_preimage++;
1150                 if (line[0] == ' ')
1151                         ecbdata->lno_in_postimage++;
1152                 emit_line(ecbdata->opt, color, reset, line, len);
1153         } else {
1154                 ecbdata->lno_in_postimage++;
1155                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1156         }
1157 }
1158
1159 static char *pprint_rename(const char *a, const char *b)
1160 {
1161         const char *old = a;
1162         const char *new = b;
1163         struct strbuf name = STRBUF_INIT;
1164         int pfx_length, sfx_length;
1165         int len_a = strlen(a);
1166         int len_b = strlen(b);
1167         int a_midlen, b_midlen;
1168         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1169         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1170
1171         if (qlen_a || qlen_b) {
1172                 quote_c_style(a, &name, NULL, 0);
1173                 strbuf_addstr(&name, " => ");
1174                 quote_c_style(b, &name, NULL, 0);
1175                 return strbuf_detach(&name, NULL);
1176         }
1177
1178         /* Find common prefix */
1179         pfx_length = 0;
1180         while (*old && *new && *old == *new) {
1181                 if (*old == '/')
1182                         pfx_length = old - a + 1;
1183                 old++;
1184                 new++;
1185         }
1186
1187         /* Find common suffix */
1188         old = a + len_a;
1189         new = b + len_b;
1190         sfx_length = 0;
1191         while (a <= old && b <= new && *old == *new) {
1192                 if (*old == '/')
1193                         sfx_length = len_a - (old - a);
1194                 old--;
1195                 new--;
1196         }
1197
1198         /*
1199          * pfx{mid-a => mid-b}sfx
1200          * {pfx-a => pfx-b}sfx
1201          * pfx{sfx-a => sfx-b}
1202          * name-a => name-b
1203          */
1204         a_midlen = len_a - pfx_length - sfx_length;
1205         b_midlen = len_b - pfx_length - sfx_length;
1206         if (a_midlen < 0)
1207                 a_midlen = 0;
1208         if (b_midlen < 0)
1209                 b_midlen = 0;
1210
1211         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1212         if (pfx_length + sfx_length) {
1213                 strbuf_add(&name, a, pfx_length);
1214                 strbuf_addch(&name, '{');
1215         }
1216         strbuf_add(&name, a + pfx_length, a_midlen);
1217         strbuf_addstr(&name, " => ");
1218         strbuf_add(&name, b + pfx_length, b_midlen);
1219         if (pfx_length + sfx_length) {
1220                 strbuf_addch(&name, '}');
1221                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1222         }
1223         return strbuf_detach(&name, NULL);
1224 }
1225
1226 struct diffstat_t {
1227         int nr;
1228         int alloc;
1229         struct diffstat_file {
1230                 char *from_name;
1231                 char *name;
1232                 char *print_name;
1233                 unsigned is_unmerged:1;
1234                 unsigned is_binary:1;
1235                 unsigned is_renamed:1;
1236                 uintmax_t added, deleted;
1237         } **files;
1238 };
1239
1240 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1241                                           const char *name_a,
1242                                           const char *name_b)
1243 {
1244         struct diffstat_file *x;
1245         x = xcalloc(sizeof (*x), 1);
1246         if (diffstat->nr == diffstat->alloc) {
1247                 diffstat->alloc = alloc_nr(diffstat->alloc);
1248                 diffstat->files = xrealloc(diffstat->files,
1249                                 diffstat->alloc * sizeof(x));
1250         }
1251         diffstat->files[diffstat->nr++] = x;
1252         if (name_b) {
1253                 x->from_name = xstrdup(name_a);
1254                 x->name = xstrdup(name_b);
1255                 x->is_renamed = 1;
1256         }
1257         else {
1258                 x->from_name = NULL;
1259                 x->name = xstrdup(name_a);
1260         }
1261         return x;
1262 }
1263
1264 static void diffstat_consume(void *priv, char *line, unsigned long len)
1265 {
1266         struct diffstat_t *diffstat = priv;
1267         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1268
1269         if (line[0] == '+')
1270                 x->added++;
1271         else if (line[0] == '-')
1272                 x->deleted++;
1273 }
1274
1275 const char mime_boundary_leader[] = "------------";
1276
1277 static int scale_linear(int it, int width, int max_change)
1278 {
1279         if (!it)
1280                 return 0;
1281         /*
1282          * make sure that at least one '-' or '+' is printed if
1283          * there is any change to this path. The easiest way is to
1284          * scale linearly as if the alloted width is one column shorter
1285          * than it is, and then add 1 to the result.
1286          */
1287         return 1 + (it * (width - 1) / max_change);
1288 }
1289
1290 static void show_name(FILE *file,
1291                       const char *prefix, const char *name, int len)
1292 {
1293         fprintf(file, " %s%-*s |", prefix, len, name);
1294 }
1295
1296 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1297 {
1298         if (cnt <= 0)
1299                 return;
1300         fprintf(file, "%s", set);
1301         while (cnt--)
1302                 putc(ch, file);
1303         fprintf(file, "%s", reset);
1304 }
1305
1306 static void fill_print_name(struct diffstat_file *file)
1307 {
1308         char *pname;
1309
1310         if (file->print_name)
1311                 return;
1312
1313         if (!file->is_renamed) {
1314                 struct strbuf buf = STRBUF_INIT;
1315                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1316                         pname = strbuf_detach(&buf, NULL);
1317                 } else {
1318                         pname = file->name;
1319                         strbuf_release(&buf);
1320                 }
1321         } else {
1322                 pname = pprint_rename(file->from_name, file->name);
1323         }
1324         file->print_name = pname;
1325 }
1326
1327 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1328 {
1329         struct strbuf sb = STRBUF_INIT;
1330         int ret;
1331
1332         if (!files) {
1333                 assert(insertions == 0 && deletions == 0);
1334                 return fputs(_(" 0 files changed\n"), fp);
1335         }
1336
1337         strbuf_addf(&sb,
1338                     Q_(" %d file changed", " %d files changed", files),
1339                     files);
1340
1341         /*
1342          * For binary diff, the caller may want to print "x files
1343          * changed" with insertions == 0 && deletions == 0.
1344          *
1345          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1346          * is probably less confusing (i.e skip over "2 files changed
1347          * but nothing about added/removed lines? Is this a bug in Git?").
1348          */
1349         if (insertions || deletions == 0) {
1350                 /*
1351                  * TRANSLATORS: "+" in (+) is a line addition marker;
1352                  * do not translate it.
1353                  */
1354                 strbuf_addf(&sb,
1355                             Q_(", %d insertion(+)", ", %d insertions(+)",
1356                                insertions),
1357                             insertions);
1358         }
1359
1360         if (deletions || insertions == 0) {
1361                 /*
1362                  * TRANSLATORS: "-" in (-) is a line removal marker;
1363                  * do not translate it.
1364                  */
1365                 strbuf_addf(&sb,
1366                             Q_(", %d deletion(-)", ", %d deletions(-)",
1367                                deletions),
1368                             deletions);
1369         }
1370         strbuf_addch(&sb, '\n');
1371         ret = fputs(sb.buf, fp);
1372         strbuf_release(&sb);
1373         return ret;
1374 }
1375
1376 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1377 {
1378         int i, len, add, del, adds = 0, dels = 0;
1379         uintmax_t max_change = 0, max_len = 0;
1380         int total_files = data->nr;
1381         int width, name_width, count;
1382         const char *reset, *add_c, *del_c;
1383         const char *line_prefix = "";
1384         int extra_shown = 0;
1385         struct strbuf *msg = NULL;
1386
1387         if (data->nr == 0)
1388                 return;
1389
1390         if (options->output_prefix) {
1391                 msg = options->output_prefix(options, options->output_prefix_data);
1392                 line_prefix = msg->buf;
1393         }
1394
1395         width = options->stat_width ? options->stat_width : 80;
1396         name_width = options->stat_name_width ? options->stat_name_width : 50;
1397         count = options->stat_count ? options->stat_count : data->nr;
1398
1399         /* Sanity: give at least 5 columns to the graph,
1400          * but leave at least 10 columns for the name.
1401          */
1402         if (width < 25)
1403                 width = 25;
1404         if (name_width < 10)
1405                 name_width = 10;
1406         else if (width < name_width + 15)
1407                 name_width = width - 15;
1408
1409         /* Find the longest filename and max number of changes */
1410         reset = diff_get_color_opt(options, DIFF_RESET);
1411         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1412         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1413
1414         for (i = 0; (i < count) && (i < data->nr); i++) {
1415                 struct diffstat_file *file = data->files[i];
1416                 uintmax_t change = file->added + file->deleted;
1417                 if (!data->files[i]->is_renamed &&
1418                          (change == 0)) {
1419                         count++; /* not shown == room for one more */
1420                         continue;
1421                 }
1422                 fill_print_name(file);
1423                 len = strlen(file->print_name);
1424                 if (max_len < len)
1425                         max_len = len;
1426
1427                 if (file->is_binary || file->is_unmerged)
1428                         continue;
1429                 if (max_change < change)
1430                         max_change = change;
1431         }
1432         count = i; /* min(count, data->nr) */
1433
1434         /* Compute the width of the graph part;
1435          * 10 is for one blank at the beginning of the line plus
1436          * " | count " between the name and the graph.
1437          *
1438          * From here on, name_width is the width of the name area,
1439          * and width is the width of the graph area.
1440          */
1441         name_width = (name_width < max_len) ? name_width : max_len;
1442         if (width < (name_width + 10) + max_change)
1443                 width = width - (name_width + 10);
1444         else
1445                 width = max_change;
1446
1447         for (i = 0; i < count; i++) {
1448                 const char *prefix = "";
1449                 char *name = data->files[i]->print_name;
1450                 uintmax_t added = data->files[i]->added;
1451                 uintmax_t deleted = data->files[i]->deleted;
1452                 int name_len;
1453
1454                 if (!data->files[i]->is_renamed &&
1455                          (added + deleted == 0)) {
1456                         total_files--;
1457                         continue;
1458                 }
1459                 /*
1460                  * "scale" the filename
1461                  */
1462                 len = name_width;
1463                 name_len = strlen(name);
1464                 if (name_width < name_len) {
1465                         char *slash;
1466                         prefix = "...";
1467                         len -= 3;
1468                         name += name_len - len;
1469                         slash = strchr(name, '/');
1470                         if (slash)
1471                                 name = slash;
1472                 }
1473
1474                 if (data->files[i]->is_binary) {
1475                         fprintf(options->file, "%s", line_prefix);
1476                         show_name(options->file, prefix, name, len);
1477                         fprintf(options->file, "  Bin ");
1478                         fprintf(options->file, "%s%"PRIuMAX"%s",
1479                                 del_c, deleted, reset);
1480                         fprintf(options->file, " -> ");
1481                         fprintf(options->file, "%s%"PRIuMAX"%s",
1482                                 add_c, added, reset);
1483                         fprintf(options->file, " bytes");
1484                         fprintf(options->file, "\n");
1485                         continue;
1486                 }
1487                 else if (data->files[i]->is_unmerged) {
1488                         fprintf(options->file, "%s", line_prefix);
1489                         show_name(options->file, prefix, name, len);
1490                         fprintf(options->file, "  Unmerged\n");
1491                         continue;
1492                 }
1493
1494                 /*
1495                  * scale the add/delete
1496                  */
1497                 add = added;
1498                 del = deleted;
1499                 adds += add;
1500                 dels += del;
1501
1502                 if (width <= max_change) {
1503                         int total = add + del;
1504
1505                         total = scale_linear(add + del, width, max_change);
1506                         if (total < 2 && add && del)
1507                                 /* width >= 2 due to the sanity check */
1508                                 total = 2;
1509                         if (add < del) {
1510                                 add = scale_linear(add, width, max_change);
1511                                 del = total - add;
1512                         } else {
1513                                 del = scale_linear(del, width, max_change);
1514                                 add = total - del;
1515                         }
1516                 }
1517                 fprintf(options->file, "%s", line_prefix);
1518                 show_name(options->file, prefix, name, len);
1519                 fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
1520                                 added + deleted ? " " : "");
1521                 show_graph(options->file, '+', add, add_c, reset);
1522                 show_graph(options->file, '-', del, del_c, reset);
1523                 fprintf(options->file, "\n");
1524         }
1525         for (i = count; i < data->nr; i++) {
1526                 uintmax_t added = data->files[i]->added;
1527                 uintmax_t deleted = data->files[i]->deleted;
1528                 if (!data->files[i]->is_renamed &&
1529                          (added + deleted == 0)) {
1530                         total_files--;
1531                         continue;
1532                 }
1533                 adds += added;
1534                 dels += deleted;
1535                 if (!extra_shown)
1536                         fprintf(options->file, "%s ...\n", line_prefix);
1537                 extra_shown = 1;
1538         }
1539         fprintf(options->file, "%s", line_prefix);
1540         print_stat_summary(options->file, total_files, adds, dels);
1541 }
1542
1543 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1544 {
1545         int i, adds = 0, dels = 0, total_files = data->nr;
1546
1547         if (data->nr == 0)
1548                 return;
1549
1550         for (i = 0; i < data->nr; i++) {
1551                 if (!data->files[i]->is_binary &&
1552                     !data->files[i]->is_unmerged) {
1553                         int added = data->files[i]->added;
1554                         int deleted= data->files[i]->deleted;
1555                         if (!data->files[i]->is_renamed &&
1556                             (added + deleted == 0)) {
1557                                 total_files--;
1558                         } else {
1559                                 adds += added;
1560                                 dels += deleted;
1561                         }
1562                 }
1563         }
1564         if (options->output_prefix) {
1565                 struct strbuf *msg = NULL;
1566                 msg = options->output_prefix(options,
1567                                 options->output_prefix_data);
1568                 fprintf(options->file, "%s", msg->buf);
1569         }
1570         print_stat_summary(options->file, total_files, adds, dels);
1571 }
1572
1573 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1574 {
1575         int i;
1576
1577         if (data->nr == 0)
1578                 return;
1579
1580         for (i = 0; i < data->nr; i++) {
1581                 struct diffstat_file *file = data->files[i];
1582
1583                 if (options->output_prefix) {
1584                         struct strbuf *msg = NULL;
1585                         msg = options->output_prefix(options,
1586                                         options->output_prefix_data);
1587                         fprintf(options->file, "%s", msg->buf);
1588                 }
1589
1590                 if (file->is_binary)
1591                         fprintf(options->file, "-\t-\t");
1592                 else
1593                         fprintf(options->file,
1594                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1595                                 file->added, file->deleted);
1596                 if (options->line_termination) {
1597                         fill_print_name(file);
1598                         if (!file->is_renamed)
1599                                 write_name_quoted(file->name, options->file,
1600                                                   options->line_termination);
1601                         else {
1602                                 fputs(file->print_name, options->file);
1603                                 putc(options->line_termination, options->file);
1604                         }
1605                 } else {
1606                         if (file->is_renamed) {
1607                                 putc('\0', options->file);
1608                                 write_name_quoted(file->from_name, options->file, '\0');
1609                         }
1610                         write_name_quoted(file->name, options->file, '\0');
1611                 }
1612         }
1613 }
1614
1615 struct dirstat_file {
1616         const char *name;
1617         unsigned long changed;
1618 };
1619
1620 struct dirstat_dir {
1621         struct dirstat_file *files;
1622         int alloc, nr, permille, cumulative;
1623 };
1624
1625 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1626                 unsigned long changed, const char *base, int baselen)
1627 {
1628         unsigned long this_dir = 0;
1629         unsigned int sources = 0;
1630         const char *line_prefix = "";
1631         struct strbuf *msg = NULL;
1632
1633         if (opt->output_prefix) {
1634                 msg = opt->output_prefix(opt, opt->output_prefix_data);
1635                 line_prefix = msg->buf;
1636         }
1637
1638         while (dir->nr) {
1639                 struct dirstat_file *f = dir->files;
1640                 int namelen = strlen(f->name);
1641                 unsigned long this;
1642                 char *slash;
1643
1644                 if (namelen < baselen)
1645                         break;
1646                 if (memcmp(f->name, base, baselen))
1647                         break;
1648                 slash = strchr(f->name + baselen, '/');
1649                 if (slash) {
1650                         int newbaselen = slash + 1 - f->name;
1651                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1652                         sources++;
1653                 } else {
1654                         this = f->changed;
1655                         dir->files++;
1656                         dir->nr--;
1657                         sources += 2;
1658                 }
1659                 this_dir += this;
1660         }
1661
1662         /*
1663          * We don't report dirstat's for
1664          *  - the top level
1665          *  - or cases where everything came from a single directory
1666          *    under this directory (sources == 1).
1667          */
1668         if (baselen && sources != 1) {
1669                 if (this_dir) {
1670                         int permille = this_dir * 1000 / changed;
1671                         if (permille >= dir->permille) {
1672                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1673                                         permille / 10, permille % 10, baselen, base);
1674                                 if (!dir->cumulative)
1675                                         return 0;
1676                         }
1677                 }
1678         }
1679         return this_dir;
1680 }
1681
1682 static int dirstat_compare(const void *_a, const void *_b)
1683 {
1684         const struct dirstat_file *a = _a;
1685         const struct dirstat_file *b = _b;
1686         return strcmp(a->name, b->name);
1687 }
1688
1689 static void show_dirstat(struct diff_options *options)
1690 {
1691         int i;
1692         unsigned long changed;
1693         struct dirstat_dir dir;
1694         struct diff_queue_struct *q = &diff_queued_diff;
1695
1696         dir.files = NULL;
1697         dir.alloc = 0;
1698         dir.nr = 0;
1699         dir.permille = options->dirstat_permille;
1700         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1701
1702         changed = 0;
1703         for (i = 0; i < q->nr; i++) {
1704                 struct diff_filepair *p = q->queue[i];
1705                 const char *name;
1706                 unsigned long copied, added, damage;
1707                 int content_changed;
1708
1709                 name = p->two->path ? p->two->path : p->one->path;
1710
1711                 if (p->one->sha1_valid && p->two->sha1_valid)
1712                         content_changed = hashcmp(p->one->sha1, p->two->sha1);
1713                 else
1714                         content_changed = 1;
1715
1716                 if (!content_changed) {
1717                         /*
1718                          * The SHA1 has not changed, so pre-/post-content is
1719                          * identical. We can therefore skip looking at the
1720                          * file contents altogether.
1721                          */
1722                         damage = 0;
1723                         goto found_damage;
1724                 }
1725
1726                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1727                         /*
1728                          * In --dirstat-by-file mode, we don't really need to
1729                          * look at the actual file contents at all.
1730                          * The fact that the SHA1 changed is enough for us to
1731                          * add this file to the list of results
1732                          * (with each file contributing equal damage).
1733                          */
1734                         damage = 1;
1735                         goto found_damage;
1736                 }
1737
1738                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1739                         diff_populate_filespec(p->one, 0);
1740                         diff_populate_filespec(p->two, 0);
1741                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1742                                                &copied, &added);
1743                         diff_free_filespec_data(p->one);
1744                         diff_free_filespec_data(p->two);
1745                 } else if (DIFF_FILE_VALID(p->one)) {
1746                         diff_populate_filespec(p->one, 1);
1747                         copied = added = 0;
1748                         diff_free_filespec_data(p->one);
1749                 } else if (DIFF_FILE_VALID(p->two)) {
1750                         diff_populate_filespec(p->two, 1);
1751                         copied = 0;
1752                         added = p->two->size;
1753                         diff_free_filespec_data(p->two);
1754                 } else
1755                         continue;
1756
1757                 /*
1758                  * Original minus copied is the removed material,
1759                  * added is the new material.  They are both damages
1760                  * made to the preimage.
1761                  * If the resulting damage is zero, we know that
1762                  * diffcore_count_changes() considers the two entries to
1763                  * be identical, but since content_changed is true, we
1764                  * know that there must have been _some_ kind of change,
1765                  * so we force all entries to have damage > 0.
1766                  */
1767                 damage = (p->one->size - copied) + added;
1768                 if (!damage)
1769                         damage = 1;
1770
1771 found_damage:
1772                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1773                 dir.files[dir.nr].name = name;
1774                 dir.files[dir.nr].changed = damage;
1775                 changed += damage;
1776                 dir.nr++;
1777         }
1778
1779         /* This can happen even with many files, if everything was renames */
1780         if (!changed)
1781                 return;
1782
1783         /* Show all directories with more than x% of the changes */
1784         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1785         gather_dirstat(options, &dir, changed, "", 0);
1786 }
1787
1788 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1789 {
1790         int i;
1791         unsigned long changed;
1792         struct dirstat_dir dir;
1793
1794         if (data->nr == 0)
1795                 return;
1796
1797         dir.files = NULL;
1798         dir.alloc = 0;
1799         dir.nr = 0;
1800         dir.permille = options->dirstat_permille;
1801         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1802
1803         changed = 0;
1804         for (i = 0; i < data->nr; i++) {
1805                 struct diffstat_file *file = data->files[i];
1806                 unsigned long damage = file->added + file->deleted;
1807                 if (file->is_binary)
1808                         /*
1809                          * binary files counts bytes, not lines. Must find some
1810                          * way to normalize binary bytes vs. textual lines.
1811                          * The following heuristic assumes that there are 64
1812                          * bytes per "line".
1813                          * This is stupid and ugly, but very cheap...
1814                          */
1815                         damage = (damage + 63) / 64;
1816                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1817                 dir.files[dir.nr].name = file->name;
1818                 dir.files[dir.nr].changed = damage;
1819                 changed += damage;
1820                 dir.nr++;
1821         }
1822
1823         /* This can happen even with many files, if everything was renames */
1824         if (!changed)
1825                 return;
1826
1827         /* Show all directories with more than x% of the changes */
1828         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1829         gather_dirstat(options, &dir, changed, "", 0);
1830 }
1831
1832 static void free_diffstat_info(struct diffstat_t *diffstat)
1833 {
1834         int i;
1835         for (i = 0; i < diffstat->nr; i++) {
1836                 struct diffstat_file *f = diffstat->files[i];
1837                 if (f->name != f->print_name)
1838                         free(f->print_name);
1839                 free(f->name);
1840                 free(f->from_name);
1841                 free(f);
1842         }
1843         free(diffstat->files);
1844 }
1845
1846 struct checkdiff_t {
1847         const char *filename;
1848         int lineno;
1849         int conflict_marker_size;
1850         struct diff_options *o;
1851         unsigned ws_rule;
1852         unsigned status;
1853 };
1854
1855 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
1856 {
1857         char firstchar;
1858         int cnt;
1859
1860         if (len < marker_size + 1)
1861                 return 0;
1862         firstchar = line[0];
1863         switch (firstchar) {
1864         case '=': case '>': case '<': case '|':
1865                 break;
1866         default:
1867                 return 0;
1868         }
1869         for (cnt = 1; cnt < marker_size; cnt++)
1870                 if (line[cnt] != firstchar)
1871                         return 0;
1872         /* line[1] thru line[marker_size-1] are same as firstchar */
1873         if (len < marker_size + 1 || !isspace(line[marker_size]))
1874                 return 0;
1875         return 1;
1876 }
1877
1878 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1879 {
1880         struct checkdiff_t *data = priv;
1881         int marker_size = data->conflict_marker_size;
1882         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
1883         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
1884         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
1885         char *err;
1886         char *line_prefix = "";
1887         struct strbuf *msgbuf;
1888
1889         assert(data->o);
1890         if (data->o->output_prefix) {
1891                 msgbuf = data->o->output_prefix(data->o,
1892                         data->o->output_prefix_data);
1893                 line_prefix = msgbuf->buf;
1894         }
1895
1896         if (line[0] == '+') {
1897                 unsigned bad;
1898                 data->lineno++;
1899                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
1900                         data->status |= 1;
1901                         fprintf(data->o->file,
1902                                 "%s%s:%d: leftover conflict marker\n",
1903                                 line_prefix, data->filename, data->lineno);
1904                 }
1905                 bad = ws_check(line + 1, len - 1, data->ws_rule);
1906                 if (!bad)
1907                         return;
1908                 data->status |= bad;
1909                 err = whitespace_error_string(bad);
1910                 fprintf(data->o->file, "%s%s:%d: %s.\n",
1911                         line_prefix, data->filename, data->lineno, err);
1912                 free(err);
1913                 emit_line(data->o, set, reset, line, 1);
1914                 ws_check_emit(line + 1, len - 1, data->ws_rule,
1915                               data->o->file, set, reset, ws);
1916         } else if (line[0] == ' ') {
1917                 data->lineno++;
1918         } else if (line[0] == '@') {
1919                 char *plus = strchr(line, '+');
1920                 if (plus)
1921                         data->lineno = strtol(plus, NULL, 10) - 1;
1922                 else
1923                         die("invalid diff");
1924         }
1925 }
1926
1927 static unsigned char *deflate_it(char *data,
1928                                  unsigned long size,
1929                                  unsigned long *result_size)
1930 {
1931         int bound;
1932         unsigned char *deflated;
1933         git_zstream stream;
1934
1935         memset(&stream, 0, sizeof(stream));
1936         git_deflate_init(&stream, zlib_compression_level);
1937         bound = git_deflate_bound(&stream, size);
1938         deflated = xmalloc(bound);
1939         stream.next_out = deflated;
1940         stream.avail_out = bound;
1941
1942         stream.next_in = (unsigned char *)data;
1943         stream.avail_in = size;
1944         while (git_deflate(&stream, Z_FINISH) == Z_OK)
1945                 ; /* nothing */
1946         git_deflate_end(&stream);
1947         *result_size = stream.total_out;
1948         return deflated;
1949 }
1950
1951 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1952 {
1953         void *cp;
1954         void *delta;
1955         void *deflated;
1956         void *data;
1957         unsigned long orig_size;
1958         unsigned long delta_size;
1959         unsigned long deflate_size;
1960         unsigned long data_size;
1961
1962         /* We could do deflated delta, or we could do just deflated two,
1963          * whichever is smaller.
1964          */
1965         delta = NULL;
1966         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1967         if (one->size && two->size) {
1968                 delta = diff_delta(one->ptr, one->size,
1969                                    two->ptr, two->size,
1970                                    &delta_size, deflate_size);
1971                 if (delta) {
1972                         void *to_free = delta;
1973                         orig_size = delta_size;
1974                         delta = deflate_it(delta, delta_size, &delta_size);
1975                         free(to_free);
1976                 }
1977         }
1978
1979         if (delta && delta_size < deflate_size) {
1980                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
1981                 free(deflated);
1982                 data = delta;
1983                 data_size = delta_size;
1984         }
1985         else {
1986                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
1987                 free(delta);
1988                 data = deflated;
1989                 data_size = deflate_size;
1990         }
1991
1992         /* emit data encoded in base85 */
1993         cp = data;
1994         while (data_size) {
1995                 int bytes = (52 < data_size) ? 52 : data_size;
1996                 char line[70];
1997                 data_size -= bytes;
1998                 if (bytes <= 26)
1999                         line[0] = bytes + 'A' - 1;
2000                 else
2001                         line[0] = bytes - 26 + 'a' - 1;
2002                 encode_85(line + 1, cp, bytes);
2003                 cp = (char *) cp + bytes;
2004                 fprintf(file, "%s", prefix);
2005                 fputs(line, file);
2006                 fputc('\n', file);
2007         }
2008         fprintf(file, "%s\n", prefix);
2009         free(data);
2010 }
2011
2012 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
2013 {
2014         fprintf(file, "%sGIT binary patch\n", prefix);
2015         emit_binary_diff_body(file, one, two, prefix);
2016         emit_binary_diff_body(file, two, one, prefix);
2017 }
2018
2019 static void diff_filespec_load_driver(struct diff_filespec *one)
2020 {
2021         /* Use already-loaded driver */
2022         if (one->driver)
2023                 return;
2024
2025         if (S_ISREG(one->mode))
2026                 one->driver = userdiff_find_by_path(one->path);
2027
2028         /* Fallback to default settings */
2029         if (!one->driver)
2030                 one->driver = userdiff_find_by_name("default");
2031 }
2032
2033 int diff_filespec_is_binary(struct diff_filespec *one)
2034 {
2035         if (one->is_binary == -1) {
2036                 diff_filespec_load_driver(one);
2037                 if (one->driver->binary != -1)
2038                         one->is_binary = one->driver->binary;
2039                 else {
2040                         if (!one->data && DIFF_FILE_VALID(one))
2041                                 diff_populate_filespec(one, 0);
2042                         if (one->data)
2043                                 one->is_binary = buffer_is_binary(one->data,
2044                                                 one->size);
2045                         if (one->is_binary == -1)
2046                                 one->is_binary = 0;
2047                 }
2048         }
2049         return one->is_binary;
2050 }
2051
2052 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2053 {
2054         diff_filespec_load_driver(one);
2055         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2056 }
2057
2058 static const char *userdiff_word_regex(struct diff_filespec *one)
2059 {
2060         diff_filespec_load_driver(one);
2061         return one->driver->word_regex;
2062 }
2063
2064 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2065 {
2066         if (!options->a_prefix)
2067                 options->a_prefix = a;
2068         if (!options->b_prefix)
2069                 options->b_prefix = b;
2070 }
2071
2072 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2073 {
2074         if (!DIFF_FILE_VALID(one))
2075                 return NULL;
2076
2077         diff_filespec_load_driver(one);
2078         return userdiff_get_textconv(one->driver);
2079 }
2080
2081 static void builtin_diff(const char *name_a,
2082                          const char *name_b,
2083                          struct diff_filespec *one,
2084                          struct diff_filespec *two,
2085                          const char *xfrm_msg,
2086                          int must_show_header,
2087                          struct diff_options *o,
2088                          int complete_rewrite)
2089 {
2090         mmfile_t mf1, mf2;
2091         const char *lbl[2];
2092         char *a_one, *b_two;
2093         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
2094         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2095         const char *a_prefix, *b_prefix;
2096         struct userdiff_driver *textconv_one = NULL;
2097         struct userdiff_driver *textconv_two = NULL;
2098         struct strbuf header = STRBUF_INIT;
2099         struct strbuf *msgbuf;
2100         char *line_prefix = "";
2101
2102         if (o->output_prefix) {
2103                 msgbuf = o->output_prefix(o, o->output_prefix_data);
2104                 line_prefix = msgbuf->buf;
2105         }
2106
2107         if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2108                         (!one->mode || S_ISGITLINK(one->mode)) &&
2109                         (!two->mode || S_ISGITLINK(two->mode))) {
2110                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2111                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2112                 show_submodule_summary(o->file, one ? one->path : two->path,
2113                                 one->sha1, two->sha1, two->dirty_submodule,
2114                                 del, add, reset);
2115                 return;
2116         }
2117
2118         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2119                 textconv_one = get_textconv(one);
2120                 textconv_two = get_textconv(two);
2121         }
2122
2123         diff_set_mnemonic_prefix(o, "a/", "b/");
2124         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2125                 a_prefix = o->b_prefix;
2126                 b_prefix = o->a_prefix;
2127         } else {
2128                 a_prefix = o->a_prefix;
2129                 b_prefix = o->b_prefix;
2130         }
2131
2132         /* Never use a non-valid filename anywhere if at all possible */
2133         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2134         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2135
2136         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2137         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2138         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2139         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2140         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
2141         if (lbl[0][0] == '/') {
2142                 /* /dev/null */
2143                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
2144                 if (xfrm_msg)
2145                         strbuf_addstr(&header, xfrm_msg);
2146                 must_show_header = 1;
2147         }
2148         else if (lbl[1][0] == '/') {
2149                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
2150                 if (xfrm_msg)
2151                         strbuf_addstr(&header, xfrm_msg);
2152                 must_show_header = 1;
2153         }
2154         else {
2155                 if (one->mode != two->mode) {
2156                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
2157                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
2158                         must_show_header = 1;
2159                 }
2160                 if (xfrm_msg)
2161                         strbuf_addstr(&header, xfrm_msg);
2162
2163                 /*
2164                  * we do not run diff between different kind
2165                  * of objects.
2166                  */
2167                 if ((one->mode ^ two->mode) & S_IFMT)
2168                         goto free_ab_and_return;
2169                 if (complete_rewrite &&
2170                     (textconv_one || !diff_filespec_is_binary(one)) &&
2171                     (textconv_two || !diff_filespec_is_binary(two))) {
2172                         fprintf(o->file, "%s", header.buf);
2173                         strbuf_reset(&header);
2174                         emit_rewrite_diff(name_a, name_b, one, two,
2175                                                 textconv_one, textconv_two, o);
2176                         o->found_changes = 1;
2177                         goto free_ab_and_return;
2178                 }
2179         }
2180
2181         if (o->irreversible_delete && lbl[1][0] == '/') {
2182                 fprintf(o->file, "%s", header.buf);
2183                 strbuf_reset(&header);
2184                 goto free_ab_and_return;
2185         } else if (!DIFF_OPT_TST(o, TEXT) &&
2186             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2187               (!textconv_two && diff_filespec_is_binary(two)) )) {
2188                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2189                         die("unable to read files to diff");
2190                 /* Quite common confusing case */
2191                 if (mf1.size == mf2.size &&
2192                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2193                         if (must_show_header)
2194                                 fprintf(o->file, "%s", header.buf);
2195                         goto free_ab_and_return;
2196                 }
2197                 fprintf(o->file, "%s", header.buf);
2198                 strbuf_reset(&header);
2199                 if (DIFF_OPT_TST(o, BINARY))
2200                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2201                 else
2202                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2203                                 line_prefix, lbl[0], lbl[1]);
2204                 o->found_changes = 1;
2205         } else {
2206                 /* Crazy xdl interfaces.. */
2207                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2208                 xpparam_t xpp;
2209                 xdemitconf_t xecfg;
2210                 struct emit_callback ecbdata;
2211                 const struct userdiff_funcname *pe;
2212
2213                 if (must_show_header) {
2214                         fprintf(o->file, "%s", header.buf);
2215                         strbuf_reset(&header);
2216                 }
2217
2218                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2219                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2220
2221                 pe = diff_funcname_pattern(one);
2222                 if (!pe)
2223                         pe = diff_funcname_pattern(two);
2224
2225                 memset(&xpp, 0, sizeof(xpp));
2226                 memset(&xecfg, 0, sizeof(xecfg));
2227                 memset(&ecbdata, 0, sizeof(ecbdata));
2228                 ecbdata.label_path = lbl;
2229                 ecbdata.color_diff = want_color(o->use_color);
2230                 ecbdata.found_changesp = &o->found_changes;
2231                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2232                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2233                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2234                 ecbdata.opt = o;
2235                 ecbdata.header = header.len ? &header : NULL;
2236                 xpp.flags = o->xdl_opts;
2237                 xecfg.ctxlen = o->context;
2238                 xecfg.interhunkctxlen = o->interhunkcontext;
2239                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2240                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2241                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2242                 if (pe)
2243                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2244                 if (!diffopts)
2245                         ;
2246                 else if (!prefixcmp(diffopts, "--unified="))
2247                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2248                 else if (!prefixcmp(diffopts, "-u"))
2249                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2250                 if (o->word_diff) {
2251                         int i;
2252
2253                         ecbdata.diff_words =
2254                                 xcalloc(1, sizeof(struct diff_words_data));
2255                         ecbdata.diff_words->type = o->word_diff;
2256                         ecbdata.diff_words->opt = o;
2257                         if (!o->word_regex)
2258                                 o->word_regex = userdiff_word_regex(one);
2259                         if (!o->word_regex)
2260                                 o->word_regex = userdiff_word_regex(two);
2261                         if (!o->word_regex)
2262                                 o->word_regex = diff_word_regex_cfg;
2263                         if (o->word_regex) {
2264                                 ecbdata.diff_words->word_regex = (regex_t *)
2265                                         xmalloc(sizeof(regex_t));
2266                                 if (regcomp(ecbdata.diff_words->word_regex,
2267                                                 o->word_regex,
2268                                                 REG_EXTENDED | REG_NEWLINE))
2269                                         die ("Invalid regular expression: %s",
2270                                                         o->word_regex);
2271                         }
2272                         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2273                                 if (o->word_diff == diff_words_styles[i].type) {
2274                                         ecbdata.diff_words->style =
2275                                                 &diff_words_styles[i];
2276                                         break;
2277                                 }
2278                         }
2279                         if (want_color(o->use_color)) {
2280                                 struct diff_words_style *st = ecbdata.diff_words->style;
2281                                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2282                                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2283                                 st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
2284                         }
2285                 }
2286                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2287                               &xpp, &xecfg);
2288                 if (o->word_diff)
2289                         free_diff_words_data(&ecbdata);
2290                 if (textconv_one)
2291                         free(mf1.ptr);
2292                 if (textconv_two)
2293                         free(mf2.ptr);
2294                 xdiff_clear_find_func(&xecfg);
2295         }
2296
2297  free_ab_and_return:
2298         strbuf_release(&header);
2299         diff_free_filespec_data(one);
2300         diff_free_filespec_data(two);
2301         free(a_one);
2302         free(b_two);
2303         return;
2304 }
2305
2306 static void builtin_diffstat(const char *name_a, const char *name_b,
2307                              struct diff_filespec *one,
2308                              struct diff_filespec *two,
2309                              struct diffstat_t *diffstat,
2310                              struct diff_options *o,
2311                              int complete_rewrite)
2312 {
2313         mmfile_t mf1, mf2;
2314         struct diffstat_file *data;
2315
2316         data = diffstat_add(diffstat, name_a, name_b);
2317
2318         if (!one || !two) {
2319                 data->is_unmerged = 1;
2320                 return;
2321         }
2322
2323         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2324                 data->is_binary = 1;
2325                 data->added = diff_filespec_size(two);
2326                 data->deleted = diff_filespec_size(one);
2327         }
2328
2329         else if (complete_rewrite) {
2330                 diff_populate_filespec(one, 0);
2331                 diff_populate_filespec(two, 0);
2332                 data->deleted = count_lines(one->data, one->size);
2333                 data->added = count_lines(two->data, two->size);
2334         }
2335
2336         else {
2337                 /* Crazy xdl interfaces.. */
2338                 xpparam_t xpp;
2339                 xdemitconf_t xecfg;
2340
2341                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2342                         die("unable to read files to diff");
2343
2344                 memset(&xpp, 0, sizeof(xpp));
2345                 memset(&xecfg, 0, sizeof(xecfg));
2346                 xpp.flags = o->xdl_opts;
2347                 xecfg.ctxlen = o->context;
2348                 xecfg.interhunkctxlen = o->interhunkcontext;
2349                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2350                               &xpp, &xecfg);
2351         }
2352
2353         diff_free_filespec_data(one);
2354         diff_free_filespec_data(two);
2355 }
2356
2357 static void builtin_checkdiff(const char *name_a, const char *name_b,
2358                               const char *attr_path,
2359                               struct diff_filespec *one,
2360                               struct diff_filespec *two,
2361                               struct diff_options *o)
2362 {
2363         mmfile_t mf1, mf2;
2364         struct checkdiff_t data;
2365
2366         if (!two)
2367                 return;
2368
2369         memset(&data, 0, sizeof(data));
2370         data.filename = name_b ? name_b : name_a;
2371         data.lineno = 0;
2372         data.o = o;
2373         data.ws_rule = whitespace_rule(attr_path);
2374         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2375
2376         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2377                 die("unable to read files to diff");
2378
2379         /*
2380          * All the other codepaths check both sides, but not checking
2381          * the "old" side here is deliberate.  We are checking the newly
2382          * introduced changes, and as long as the "new" side is text, we
2383          * can and should check what it introduces.
2384          */
2385         if (diff_filespec_is_binary(two))
2386                 goto free_and_return;
2387         else {
2388                 /* Crazy xdl interfaces.. */
2389                 xpparam_t xpp;
2390                 xdemitconf_t xecfg;
2391
2392                 memset(&xpp, 0, sizeof(xpp));
2393                 memset(&xecfg, 0, sizeof(xecfg));
2394                 xecfg.ctxlen = 1; /* at least one context line */
2395                 xpp.flags = 0;
2396                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2397                               &xpp, &xecfg);
2398
2399                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2400                         struct emit_callback ecbdata;
2401                         int blank_at_eof;
2402
2403                         ecbdata.ws_rule = data.ws_rule;
2404                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2405                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2406
2407                         if (blank_at_eof) {
2408                                 static char *err;
2409                                 if (!err)
2410                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2411                                 fprintf(o->file, "%s:%d: %s.\n",
2412                                         data.filename, blank_at_eof, err);
2413                                 data.status = 1; /* report errors */
2414                         }
2415                 }
2416         }
2417  free_and_return:
2418         diff_free_filespec_data(one);
2419         diff_free_filespec_data(two);
2420         if (data.status)
2421                 DIFF_OPT_SET(o, CHECK_FAILED);
2422 }
2423
2424 struct diff_filespec *alloc_filespec(const char *path)
2425 {
2426         int namelen = strlen(path);
2427         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2428
2429         memset(spec, 0, sizeof(*spec));
2430         spec->path = (char *)(spec + 1);
2431         memcpy(spec->path, path, namelen+1);
2432         spec->count = 1;
2433         spec->is_binary = -1;
2434         return spec;
2435 }
2436
2437 void free_filespec(struct diff_filespec *spec)
2438 {
2439         if (!--spec->count) {
2440                 diff_free_filespec_data(spec);
2441                 free(spec);
2442         }
2443 }
2444
2445 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2446                    unsigned short mode)
2447 {
2448         if (mode) {
2449                 spec->mode = canon_mode(mode);
2450                 hashcpy(spec->sha1, sha1);
2451                 spec->sha1_valid = !is_null_sha1(sha1);
2452         }
2453 }
2454
2455 /*
2456  * Given a name and sha1 pair, if the index tells us the file in
2457  * the work tree has that object contents, return true, so that
2458  * prepare_temp_file() does not have to inflate and extract.
2459  */
2460 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2461 {
2462         struct cache_entry *ce;
2463         struct stat st;
2464         int pos, len;
2465
2466         /*
2467          * We do not read the cache ourselves here, because the
2468          * benchmark with my previous version that always reads cache
2469          * shows that it makes things worse for diff-tree comparing
2470          * two linux-2.6 kernel trees in an already checked out work
2471          * tree.  This is because most diff-tree comparisons deal with
2472          * only a small number of files, while reading the cache is
2473          * expensive for a large project, and its cost outweighs the
2474          * savings we get by not inflating the object to a temporary
2475          * file.  Practically, this code only helps when we are used
2476          * by diff-cache --cached, which does read the cache before
2477          * calling us.
2478          */
2479         if (!active_cache)
2480                 return 0;
2481
2482         /* We want to avoid the working directory if our caller
2483          * doesn't need the data in a normal file, this system
2484          * is rather slow with its stat/open/mmap/close syscalls,
2485          * and the object is contained in a pack file.  The pack
2486          * is probably already open and will be faster to obtain
2487          * the data through than the working directory.  Loose
2488          * objects however would tend to be slower as they need
2489          * to be individually opened and inflated.
2490          */
2491         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2492                 return 0;
2493
2494         len = strlen(name);
2495         pos = cache_name_pos(name, len);
2496         if (pos < 0)
2497                 return 0;
2498         ce = active_cache[pos];
2499
2500         /*
2501          * This is not the sha1 we are looking for, or
2502          * unreusable because it is not a regular file.
2503          */
2504         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2505                 return 0;
2506
2507         /*
2508          * If ce is marked as "assume unchanged", there is no
2509          * guarantee that work tree matches what we are looking for.
2510          */
2511         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2512                 return 0;
2513
2514         /*
2515          * If ce matches the file in the work tree, we can reuse it.
2516          */
2517         if (ce_uptodate(ce) ||
2518             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2519                 return 1;
2520
2521         return 0;
2522 }
2523
2524 static int populate_from_stdin(struct diff_filespec *s)
2525 {
2526         struct strbuf buf = STRBUF_INIT;
2527         size_t size = 0;
2528
2529         if (strbuf_read(&buf, 0, 0) < 0)
2530                 return error("error while reading from stdin %s",
2531                                      strerror(errno));
2532
2533         s->should_munmap = 0;
2534         s->data = strbuf_detach(&buf, &size);
2535         s->size = size;
2536         s->should_free = 1;
2537         return 0;
2538 }
2539
2540 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2541 {
2542         int len;
2543         char *data = xmalloc(100), *dirty = "";
2544
2545         /* Are we looking at the work tree? */
2546         if (s->dirty_submodule)
2547                 dirty = "-dirty";
2548
2549         len = snprintf(data, 100,
2550                        "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2551         s->data = data;
2552         s->size = len;
2553         s->should_free = 1;
2554         if (size_only) {
2555                 s->data = NULL;
2556                 free(data);
2557         }
2558         return 0;
2559 }
2560
2561 /*
2562  * While doing rename detection and pickaxe operation, we may need to
2563  * grab the data for the blob (or file) for our own in-core comparison.
2564  * diff_filespec has data and size fields for this purpose.
2565  */
2566 int diff_populate_filespec(struct diff_filespec *s, int size_only)
2567 {
2568         int err = 0;
2569         if (!DIFF_FILE_VALID(s))
2570                 die("internal error: asking to populate invalid file.");
2571         if (S_ISDIR(s->mode))
2572                 return -1;
2573
2574         if (s->data)
2575                 return 0;
2576
2577         if (size_only && 0 < s->size)
2578                 return 0;
2579
2580         if (S_ISGITLINK(s->mode))
2581                 return diff_populate_gitlink(s, size_only);
2582
2583         if (!s->sha1_valid ||
2584             reuse_worktree_file(s->path, s->sha1, 0)) {
2585                 struct strbuf buf = STRBUF_INIT;
2586                 struct stat st;
2587                 int fd;
2588
2589                 if (!strcmp(s->path, "-"))
2590                         return populate_from_stdin(s);
2591
2592                 if (lstat(s->path, &st) < 0) {
2593                         if (errno == ENOENT) {
2594                         err_empty:
2595                                 err = -1;
2596                         empty:
2597                                 s->data = (char *)"";
2598                                 s->size = 0;
2599                                 return err;
2600                         }
2601                 }
2602                 s->size = xsize_t(st.st_size);
2603                 if (!s->size)
2604                         goto empty;
2605                 if (S_ISLNK(st.st_mode)) {
2606                         struct strbuf sb = STRBUF_INIT;
2607
2608                         if (strbuf_readlink(&sb, s->path, s->size))
2609                                 goto err_empty;
2610                         s->size = sb.len;
2611                         s->data = strbuf_detach(&sb, NULL);
2612                         s->should_free = 1;
2613                         return 0;
2614                 }
2615                 if (size_only)
2616                         return 0;
2617                 fd = open(s->path, O_RDONLY);
2618                 if (fd < 0)
2619                         goto err_empty;
2620                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2621                 close(fd);
2622                 s->should_munmap = 1;
2623
2624                 /*
2625                  * Convert from working tree format to canonical git format
2626                  */
2627                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2628                         size_t size = 0;
2629                         munmap(s->data, s->size);
2630                         s->should_munmap = 0;
2631                         s->data = strbuf_detach(&buf, &size);
2632                         s->size = size;
2633                         s->should_free = 1;
2634                 }
2635         }
2636         else {
2637                 enum object_type type;
2638                 if (size_only) {
2639                         type = sha1_object_info(s->sha1, &s->size);
2640                         if (type < 0)
2641                                 die("unable to read %s", sha1_to_hex(s->sha1));
2642                 } else {
2643                         s->data = read_sha1_file(s->sha1, &type, &s->size);
2644                         if (!s->data)
2645                                 die("unable to read %s", sha1_to_hex(s->sha1));
2646                         s->should_free = 1;
2647                 }
2648         }
2649         return 0;
2650 }
2651
2652 void diff_free_filespec_blob(struct diff_filespec *s)
2653 {
2654         if (s->should_free)
2655                 free(s->data);
2656         else if (s->should_munmap)
2657                 munmap(s->data, s->size);
2658
2659         if (s->should_free || s->should_munmap) {
2660                 s->should_free = s->should_munmap = 0;
2661                 s->data = NULL;
2662         }
2663 }
2664
2665 void diff_free_filespec_data(struct diff_filespec *s)
2666 {
2667         diff_free_filespec_blob(s);
2668         free(s->cnt_data);
2669         s->cnt_data = NULL;
2670 }
2671
2672 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2673                            void *blob,
2674                            unsigned long size,
2675                            const unsigned char *sha1,
2676                            int mode)
2677 {
2678         int fd;
2679         struct strbuf buf = STRBUF_INIT;
2680         struct strbuf template = STRBUF_INIT;
2681         char *path_dup = xstrdup(path);
2682         const char *base = basename(path_dup);
2683
2684         /* Generate "XXXXXX_basename.ext" */
2685         strbuf_addstr(&template, "XXXXXX_");
2686         strbuf_addstr(&template, base);
2687
2688         fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2689                         strlen(base) + 1);
2690         if (fd < 0)
2691                 die_errno("unable to create temp-file");
2692         if (convert_to_working_tree(path,
2693                         (const char *)blob, (size_t)size, &buf)) {
2694                 blob = buf.buf;
2695                 size = buf.len;
2696         }
2697         if (write_in_full(fd, blob, size) != size)
2698                 die_errno("unable to write temp-file");
2699         close(fd);
2700         temp->name = temp->tmp_path;
2701         strcpy(temp->hex, sha1_to_hex(sha1));
2702         temp->hex[40] = 0;
2703         sprintf(temp->mode, "%06o", mode);
2704         strbuf_release(&buf);
2705         strbuf_release(&template);
2706         free(path_dup);
2707 }
2708
2709 static struct diff_tempfile *prepare_temp_file(const char *name,
2710                 struct diff_filespec *one)
2711 {
2712         struct diff_tempfile *temp = claim_diff_tempfile();
2713
2714         if (!DIFF_FILE_VALID(one)) {
2715         not_a_valid_file:
2716                 /* A '-' entry produces this for file-2, and
2717                  * a '+' entry produces this for file-1.
2718                  */
2719                 temp->name = "/dev/null";
2720                 strcpy(temp->hex, ".");
2721                 strcpy(temp->mode, ".");
2722                 return temp;
2723         }
2724
2725         if (!remove_tempfile_installed) {
2726                 atexit(remove_tempfile);
2727                 sigchain_push_common(remove_tempfile_on_signal);
2728                 remove_tempfile_installed = 1;
2729         }
2730
2731         if (!one->sha1_valid ||
2732             reuse_worktree_file(name, one->sha1, 1)) {
2733                 struct stat st;
2734                 if (lstat(name, &st) < 0) {
2735                         if (errno == ENOENT)
2736                                 goto not_a_valid_file;
2737                         die_errno("stat(%s)", name);
2738                 }
2739                 if (S_ISLNK(st.st_mode)) {
2740                         struct strbuf sb = STRBUF_INIT;
2741                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
2742                                 die_errno("readlink(%s)", name);
2743                         prep_temp_blob(name, temp, sb.buf, sb.len,
2744                                        (one->sha1_valid ?
2745                                         one->sha1 : null_sha1),
2746                                        (one->sha1_valid ?
2747                                         one->mode : S_IFLNK));
2748                         strbuf_release(&sb);
2749                 }
2750                 else {
2751                         /* we can borrow from the file in the work tree */
2752                         temp->name = name;
2753                         if (!one->sha1_valid)
2754                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
2755                         else
2756                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
2757                         /* Even though we may sometimes borrow the
2758                          * contents from the work tree, we always want
2759                          * one->mode.  mode is trustworthy even when
2760                          * !(one->sha1_valid), as long as
2761                          * DIFF_FILE_VALID(one).
2762                          */
2763                         sprintf(temp->mode, "%06o", one->mode);
2764                 }
2765                 return temp;
2766         }
2767         else {
2768                 if (diff_populate_filespec(one, 0))
2769                         die("cannot read data blob for %s", one->path);
2770                 prep_temp_blob(name, temp, one->data, one->size,
2771                                one->sha1, one->mode);
2772         }
2773         return temp;
2774 }
2775
2776 /* An external diff command takes:
2777  *
2778  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2779  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2780  *
2781  */
2782 static void run_external_diff(const char *pgm,
2783                               const char *name,
2784                               const char *other,
2785                               struct diff_filespec *one,
2786                               struct diff_filespec *two,
2787                               const char *xfrm_msg,
2788                               int complete_rewrite)
2789 {
2790         const char *spawn_arg[10];
2791         int retval;
2792         const char **arg = &spawn_arg[0];
2793
2794         if (one && two) {
2795                 struct diff_tempfile *temp_one, *temp_two;
2796                 const char *othername = (other ? other : name);
2797                 temp_one = prepare_temp_file(name, one);
2798                 temp_two = prepare_temp_file(othername, two);
2799                 *arg++ = pgm;
2800                 *arg++ = name;
2801                 *arg++ = temp_one->name;
2802                 *arg++ = temp_one->hex;
2803                 *arg++ = temp_one->mode;
2804                 *arg++ = temp_two->name;
2805                 *arg++ = temp_two->hex;
2806                 *arg++ = temp_two->mode;
2807                 if (other) {
2808                         *arg++ = other;
2809                         *arg++ = xfrm_msg;
2810                 }
2811         } else {
2812                 *arg++ = pgm;
2813                 *arg++ = name;
2814         }
2815         *arg = NULL;
2816         fflush(NULL);
2817         retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2818         remove_tempfile();
2819         if (retval) {
2820                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2821                 exit(1);
2822         }
2823 }
2824
2825 static int similarity_index(struct diff_filepair *p)
2826 {
2827         return p->score * 100 / MAX_SCORE;
2828 }
2829
2830 static void fill_metainfo(struct strbuf *msg,
2831                           const char *name,
2832                           const char *other,
2833                           struct diff_filespec *one,
2834                           struct diff_filespec *two,
2835                           struct diff_options *o,
2836                           struct diff_filepair *p,
2837                           int *must_show_header,
2838                           int use_color)
2839 {
2840         const char *set = diff_get_color(use_color, DIFF_METAINFO);
2841         const char *reset = diff_get_color(use_color, DIFF_RESET);
2842         struct strbuf *msgbuf;
2843         char *line_prefix = "";
2844
2845         *must_show_header = 1;
2846         if (o->output_prefix) {
2847                 msgbuf = o->output_prefix(o, o->output_prefix_data);
2848                 line_prefix = msgbuf->buf;
2849         }
2850         strbuf_init(msg, PATH_MAX * 2 + 300);
2851         switch (p->status) {
2852         case DIFF_STATUS_COPIED:
2853                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2854                             line_prefix, set, similarity_index(p));
2855                 strbuf_addf(msg, "%s\n%s%scopy from ",
2856                             reset,  line_prefix, set);
2857                 quote_c_style(name, msg, NULL, 0);
2858                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2859                 quote_c_style(other, msg, NULL, 0);
2860                 strbuf_addf(msg, "%s\n", reset);
2861                 break;
2862         case DIFF_STATUS_RENAMED:
2863                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2864                             line_prefix, set, similarity_index(p));
2865                 strbuf_addf(msg, "%s\n%s%srename from ",
2866                             reset, line_prefix, set);
2867                 quote_c_style(name, msg, NULL, 0);
2868                 strbuf_addf(msg, "%s\n%s%srename to ",
2869                             reset, line_prefix, set);
2870                 quote_c_style(other, msg, NULL, 0);
2871                 strbuf_addf(msg, "%s\n", reset);
2872                 break;
2873         case DIFF_STATUS_MODIFIED:
2874                 if (p->score) {
2875                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2876                                     line_prefix,
2877                                     set, similarity_index(p), reset);
2878                         break;
2879                 }
2880                 /* fallthru */
2881         default:
2882                 *must_show_header = 0;
2883         }
2884         if (one && two && hashcmp(one->sha1, two->sha1)) {
2885                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2886
2887                 if (DIFF_OPT_TST(o, BINARY)) {
2888                         mmfile_t mf;
2889                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2890                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2891                                 abbrev = 40;
2892                 }
2893                 strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2894                             find_unique_abbrev(one->sha1, abbrev));
2895                 strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2896                 if (one->mode == two->mode)
2897                         strbuf_addf(msg, " %06o", one->mode);
2898                 strbuf_addf(msg, "%s\n", reset);
2899         }
2900 }
2901
2902 static void run_diff_cmd(const char *pgm,
2903                          const char *name,
2904                          const char *other,
2905                          const char *attr_path,
2906                          struct diff_filespec *one,
2907                          struct diff_filespec *two,
2908                          struct strbuf *msg,
2909                          struct diff_options *o,
2910                          struct diff_filepair *p)
2911 {
2912         const char *xfrm_msg = NULL;
2913         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
2914         int must_show_header = 0;
2915
2916
2917         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
2918                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
2919                 if (drv && drv->external)
2920                         pgm = drv->external;
2921         }
2922
2923         if (msg) {
2924                 /*
2925                  * don't use colors when the header is intended for an
2926                  * external diff driver
2927                  */
2928                 fill_metainfo(msg, name, other, one, two, o, p,
2929                               &must_show_header,
2930                               want_color(o->use_color) && !pgm);
2931                 xfrm_msg = msg->len ? msg->buf : NULL;
2932         }
2933
2934         if (pgm) {
2935                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
2936                                   complete_rewrite);
2937                 return;
2938         }
2939         if (one && two)
2940                 builtin_diff(name, other ? other : name,
2941                              one, two, xfrm_msg, must_show_header,
2942                              o, complete_rewrite);
2943         else
2944                 fprintf(o->file, "* Unmerged path %s\n", name);
2945 }
2946
2947 static void diff_fill_sha1_info(struct diff_filespec *one)
2948 {
2949         if (DIFF_FILE_VALID(one)) {
2950                 if (!one->sha1_valid) {
2951                         struct stat st;
2952                         if (!strcmp(one->path, "-")) {
2953                                 hashcpy(one->sha1, null_sha1);
2954                                 return;
2955                         }
2956                         if (lstat(one->path, &st) < 0)
2957                                 die_errno("stat '%s'", one->path);
2958                         if (index_path(one->sha1, one->path, &st, 0))
2959                                 die("cannot hash %s", one->path);
2960                 }
2961         }
2962         else
2963                 hashclr(one->sha1);
2964 }
2965
2966 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2967 {
2968         /* Strip the prefix but do not molest /dev/null and absolute paths */
2969         if (*namep && **namep != '/') {
2970                 *namep += prefix_length;
2971                 if (**namep == '/')
2972                         ++*namep;
2973         }
2974         if (*otherp && **otherp != '/') {
2975                 *otherp += prefix_length;
2976                 if (**otherp == '/')
2977                         ++*otherp;
2978         }
2979 }
2980
2981 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2982 {
2983         const char *pgm = external_diff();
2984         struct strbuf msg;
2985         struct diff_filespec *one = p->one;
2986         struct diff_filespec *two = p->two;
2987         const char *name;
2988         const char *other;
2989         const char *attr_path;
2990
2991         name  = p->one->path;
2992         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2993         attr_path = name;
2994         if (o->prefix_length)
2995                 strip_prefix(o->prefix_length, &name, &other);
2996
2997         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2998                 pgm = NULL;
2999
3000         if (DIFF_PAIR_UNMERGED(p)) {
3001                 run_diff_cmd(pgm, name, NULL, attr_path,
3002                              NULL, NULL, NULL, o, p);
3003                 return;
3004         }
3005
3006         diff_fill_sha1_info(one);
3007         diff_fill_sha1_info(two);
3008
3009         if (!pgm &&
3010             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3011             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3012                 /*
3013                  * a filepair that changes between file and symlink
3014                  * needs to be split into deletion and creation.
3015                  */
3016                 struct diff_filespec *null = alloc_filespec(two->path);
3017                 run_diff_cmd(NULL, name, other, attr_path,
3018                              one, null, &msg, o, p);
3019                 free(null);
3020                 strbuf_release(&msg);
3021
3022                 null = alloc_filespec(one->path);
3023                 run_diff_cmd(NULL, name, other, attr_path,
3024                              null, two, &msg, o, p);
3025                 free(null);
3026         }
3027         else
3028                 run_diff_cmd(pgm, name, other, attr_path,
3029                              one, two, &msg, o, p);
3030
3031         strbuf_release(&msg);
3032 }
3033
3034 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3035                          struct diffstat_t *diffstat)
3036 {
3037         const char *name;
3038         const char *other;
3039         int complete_rewrite = 0;
3040
3041         if (DIFF_PAIR_UNMERGED(p)) {
3042                 /* unmerged */
3043                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
3044                 return;
3045         }
3046
3047         name = p->one->path;
3048         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3049
3050         if (o->prefix_length)
3051                 strip_prefix(o->prefix_length, &name, &other);
3052
3053         diff_fill_sha1_info(p->one);
3054         diff_fill_sha1_info(p->two);
3055
3056         if (p->status == DIFF_STATUS_MODIFIED && p->score)
3057                 complete_rewrite = 1;
3058         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
3059 }
3060
3061 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3062 {
3063         const char *name;
3064         const char *other;
3065         const char *attr_path;
3066
3067         if (DIFF_PAIR_UNMERGED(p)) {
3068                 /* unmerged */
3069                 return;
3070         }
3071
3072         name = p->one->path;
3073         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3074         attr_path = other ? other : name;
3075
3076         if (o->prefix_length)
3077                 strip_prefix(o->prefix_length, &name, &other);
3078
3079         diff_fill_sha1_info(p->one);
3080         diff_fill_sha1_info(p->two);
3081
3082         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3083 }
3084
3085 void diff_setup(struct diff_options *options)
3086 {
3087         memcpy(options, &default_diff_options, sizeof(*options));
3088
3089         options->file = stdout;
3090
3091         options->line_termination = '\n';
3092         options->break_opt = -1;
3093         options->rename_limit = -1;
3094         options->dirstat_permille = diff_dirstat_permille_default;
3095         options->context = 3;
3096
3097         options->change = diff_change;
3098         options->add_remove = diff_addremove;
3099         options->use_color = diff_use_color_default;
3100         options->detect_rename = diff_detect_rename_default;
3101
3102         if (diff_no_prefix) {
3103                 options->a_prefix = options->b_prefix = "";
3104         } else if (!diff_mnemonic_prefix) {
3105                 options->a_prefix = "a/";
3106                 options->b_prefix = "b/";
3107         }
3108 }
3109
3110 int diff_setup_done(struct diff_options *options)
3111 {
3112         int count = 0;
3113
3114         if (options->output_format & DIFF_FORMAT_NAME)
3115                 count++;
3116         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3117                 count++;
3118         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3119                 count++;
3120         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3121                 count++;
3122         if (count > 1)
3123                 die("--name-only, --name-status, --check and -s are mutually exclusive");
3124
3125         /*
3126          * Most of the time we can say "there are changes"
3127          * only by checking if there are changed paths, but
3128          * --ignore-whitespace* options force us to look
3129          * inside contents.
3130          */
3131
3132         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3133             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3134             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3135                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3136         else
3137                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3138
3139         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3140                 options->detect_rename = DIFF_DETECT_COPY;
3141
3142         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3143                 options->prefix = NULL;
3144         if (options->prefix)
3145                 options->prefix_length = strlen(options->prefix);
3146         else
3147                 options->prefix_length = 0;
3148
3149         if (options->output_format & (DIFF_FORMAT_NAME |
3150                                       DIFF_FORMAT_NAME_STATUS |
3151                                       DIFF_FORMAT_CHECKDIFF |
3152                                       DIFF_FORMAT_NO_OUTPUT))
3153                 options->output_format &= ~(DIFF_FORMAT_RAW |
3154                                             DIFF_FORMAT_NUMSTAT |
3155                                             DIFF_FORMAT_DIFFSTAT |
3156                                             DIFF_FORMAT_SHORTSTAT |
3157                                             DIFF_FORMAT_DIRSTAT |
3158                                             DIFF_FORMAT_SUMMARY |
3159                                             DIFF_FORMAT_PATCH);
3160
3161         /*
3162          * These cases always need recursive; we do not drop caller-supplied
3163          * recursive bits for other formats here.
3164          */
3165         if (options->output_format & (DIFF_FORMAT_PATCH |
3166                                       DIFF_FORMAT_NUMSTAT |
3167                                       DIFF_FORMAT_DIFFSTAT |
3168                                       DIFF_FORMAT_SHORTSTAT |
3169                                       DIFF_FORMAT_DIRSTAT |
3170                                       DIFF_FORMAT_SUMMARY |
3171                                       DIFF_FORMAT_CHECKDIFF))
3172                 DIFF_OPT_SET(options, RECURSIVE);
3173         /*
3174          * Also pickaxe would not work very well if you do not say recursive
3175          */
3176         if (options->pickaxe)
3177                 DIFF_OPT_SET(options, RECURSIVE);
3178         /*
3179          * When patches are generated, submodules diffed against the work tree
3180          * must be checked for dirtiness too so it can be shown in the output
3181          */
3182         if (options->output_format & DIFF_FORMAT_PATCH)
3183                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3184
3185         if (options->detect_rename && options->rename_limit < 0)
3186                 options->rename_limit = diff_rename_limit_default;
3187         if (options->setup & DIFF_SETUP_USE_CACHE) {
3188                 if (!active_cache)
3189                         /* read-cache does not die even when it fails
3190                          * so it is safe for us to do this here.  Also
3191                          * it does not smudge active_cache or active_nr
3192                          * when it fails, so we do not have to worry about
3193                          * cleaning it up ourselves either.
3194                          */
3195                         read_cache();
3196         }
3197         if (options->abbrev <= 0 || 40 < options->abbrev)
3198                 options->abbrev = 40; /* full */
3199
3200         /*
3201          * It does not make sense to show the first hit we happened
3202          * to have found.  It does not make sense not to return with
3203          * exit code in such a case either.
3204          */
3205         if (DIFF_OPT_TST(options, QUICK)) {
3206                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3207                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3208         }
3209
3210         return 0;
3211 }
3212
3213 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3214 {
3215         char c, *eq;
3216         int len;
3217
3218         if (*arg != '-')
3219                 return 0;
3220         c = *++arg;
3221         if (!c)
3222                 return 0;
3223         if (c == arg_short) {
3224                 c = *++arg;
3225                 if (!c)
3226                         return 1;
3227                 if (val && isdigit(c)) {
3228                         char *end;
3229                         int n = strtoul(arg, &end, 10);
3230                         if (*end)
3231                                 return 0;
3232                         *val = n;
3233                         return 1;
3234                 }
3235                 return 0;
3236         }
3237         if (c != '-')
3238                 return 0;
3239         arg++;
3240         eq = strchr(arg, '=');
3241         if (eq)
3242                 len = eq - arg;
3243         else
3244                 len = strlen(arg);
3245         if (!len || strncmp(arg, arg_long, len))
3246                 return 0;
3247         if (eq) {
3248                 int n;
3249                 char *end;
3250                 if (!isdigit(*++eq))
3251                         return 0;
3252                 n = strtoul(eq, &end, 10);
3253                 if (*end)
3254                         return 0;
3255                 *val = n;
3256         }
3257         return 1;
3258 }
3259
3260 static int diff_scoreopt_parse(const char *opt);
3261
3262 static inline int short_opt(char opt, const char **argv,
3263                             const char **optarg)
3264 {
3265         const char *arg = argv[0];
3266         if (arg[0] != '-' || arg[1] != opt)
3267                 return 0;
3268         if (arg[2] != '\0') {
3269                 *optarg = arg + 2;
3270                 return 1;
3271         }
3272         if (!argv[1])
3273                 die("Option '%c' requires a value", opt);
3274         *optarg = argv[1];
3275         return 2;
3276 }
3277
3278 int parse_long_opt(const char *opt, const char **argv,
3279                    const char **optarg)
3280 {
3281         const char *arg = argv[0];
3282         if (arg[0] != '-' || arg[1] != '-')
3283                 return 0;
3284         arg += strlen("--");
3285         if (prefixcmp(arg, opt))
3286                 return 0;
3287         arg += strlen(opt);
3288         if (*arg == '=') { /* sticked form: --option=value */
3289                 *optarg = arg + 1;
3290                 return 1;
3291         }
3292         if (*arg != '\0')
3293                 return 0;
3294         /* separate form: --option value */
3295         if (!argv[1])
3296                 die("Option '--%s' requires a value", opt);
3297         *optarg = argv[1];
3298         return 2;
3299 }
3300
3301 static int stat_opt(struct diff_options *options, const char **av)
3302 {
3303         const char *arg = av[0];
3304         char *end;
3305         int width = options->stat_width;
3306         int name_width = options->stat_name_width;
3307         int count = options->stat_count;
3308         int argcount = 1;
3309
3310         arg += strlen("--stat");
3311         end = (char *)arg;
3312
3313         switch (*arg) {
3314         case '-':
3315                 if (!prefixcmp(arg, "-width")) {
3316                         arg += strlen("-width");
3317                         if (*arg == '=')
3318                                 width = strtoul(arg + 1, &end, 10);
3319                         else if (!*arg && !av[1])
3320                                 die("Option '--stat-width' requires a value");
3321                         else if (!*arg) {
3322                                 width = strtoul(av[1], &end, 10);
3323                                 argcount = 2;
3324                         }
3325                 } else if (!prefixcmp(arg, "-name-width")) {
3326                         arg += strlen("-name-width");
3327                         if (*arg == '=')
3328                                 name_width = strtoul(arg + 1, &end, 10);
3329                         else if (!*arg && !av[1])
3330                                 die("Option '--stat-name-width' requires a value");
3331                         else if (!*arg) {
3332                                 name_width = strtoul(av[1], &end, 10);
3333                                 argcount = 2;
3334                         }
3335                 } else if (!prefixcmp(arg, "-count")) {
3336                         arg += strlen("-count");
3337                         if (*arg == '=')
3338                                 count = strtoul(arg + 1, &end, 10);
3339                         else if (!*arg && !av[1])
3340                                 die("Option '--stat-count' requires a value");
3341                         else if (!*arg) {
3342                                 count = strtoul(av[1], &end, 10);
3343                                 argcount = 2;
3344                         }
3345                 }
3346                 break;
3347         case '=':
3348                 width = strtoul(arg+1, &end, 10);
3349                 if (*end == ',')
3350                         name_width = strtoul(end+1, &end, 10);
3351                 if (*end == ',')
3352                         count = strtoul(end+1, &end, 10);
3353         }
3354
3355         /* Important! This checks all the error cases! */
3356         if (*end)
3357                 return 0;
3358         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3359         options->stat_name_width = name_width;
3360         options->stat_width = width;
3361         options->stat_count = count;
3362         return argcount;
3363 }
3364
3365 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3366 {
3367         struct strbuf errmsg = STRBUF_INIT;
3368         if (parse_dirstat_params(options, params, &errmsg))
3369                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3370                     errmsg.buf);
3371         strbuf_release(&errmsg);
3372         /*
3373          * The caller knows a dirstat-related option is given from the command
3374          * line; allow it to say "return this_function();"
3375          */
3376         options->output_format |= DIFF_FORMAT_DIRSTAT;
3377         return 1;
3378 }
3379
3380 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3381 {
3382         const char *arg = av[0];
3383         const char *optarg;
3384         int argcount;
3385
3386         /* Output format options */
3387         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3388                 options->output_format |= DIFF_FORMAT_PATCH;
3389         else if (opt_arg(arg, 'U', "unified", &options->context))
3390                 options->output_format |= DIFF_FORMAT_PATCH;
3391         else if (!strcmp(arg, "--raw"))
3392                 options->output_format |= DIFF_FORMAT_RAW;
3393         else if (!strcmp(arg, "--patch-with-raw"))
3394                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3395         else if (!strcmp(arg, "--numstat"))
3396                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3397         else if (!strcmp(arg, "--shortstat"))
3398                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3399         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3400                 return parse_dirstat_opt(options, "");
3401         else if (!prefixcmp(arg, "-X"))
3402                 return parse_dirstat_opt(options, arg + 2);
3403         else if (!prefixcmp(arg, "--dirstat="))
3404                 return parse_dirstat_opt(options, arg + 10);
3405         else if (!strcmp(arg, "--cumulative"))
3406                 return parse_dirstat_opt(options, "cumulative");
3407         else if (!strcmp(arg, "--dirstat-by-file"))
3408                 return parse_dirstat_opt(options, "files");
3409         else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3410                 parse_dirstat_opt(options, "files");
3411                 return parse_dirstat_opt(options, arg + 18);
3412         }
3413         else if (!strcmp(arg, "--check"))
3414                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3415         else if (!strcmp(arg, "--summary"))
3416                 options->output_format |= DIFF_FORMAT_SUMMARY;
3417         else if (!strcmp(arg, "--patch-with-stat"))
3418                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3419         else if (!strcmp(arg, "--name-only"))
3420                 options->output_format |= DIFF_FORMAT_NAME;
3421         else if (!strcmp(arg, "--name-status"))
3422                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3423         else if (!strcmp(arg, "-s"))
3424                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3425         else if (!prefixcmp(arg, "--stat"))
3426                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3427                 return stat_opt(options, av);
3428
3429         /* renames options */
3430         else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3431                  !strcmp(arg, "--break-rewrites")) {
3432                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3433                         return error("invalid argument to -B: %s", arg+2);
3434         }
3435         else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3436                  !strcmp(arg, "--find-renames")) {
3437                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3438                         return error("invalid argument to -M: %s", arg+2);
3439                 options->detect_rename = DIFF_DETECT_RENAME;
3440         }
3441         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3442                 options->irreversible_delete = 1;
3443         }
3444         else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3445                  !strcmp(arg, "--find-copies")) {
3446                 if (options->detect_rename == DIFF_DETECT_COPY)
3447                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3448                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3449                         return error("invalid argument to -C: %s", arg+2);
3450                 options->detect_rename = DIFF_DETECT_COPY;
3451         }
3452         else if (!strcmp(arg, "--no-renames"))
3453                 options->detect_rename = 0;
3454         else if (!strcmp(arg, "--relative"))
3455                 DIFF_OPT_SET(options, RELATIVE_NAME);
3456         else if (!prefixcmp(arg, "--relative=")) {
3457                 DIFF_OPT_SET(options, RELATIVE_NAME);
3458                 options->prefix = arg + 11;
3459         }
3460
3461         /* xdiff options */
3462         else if (!strcmp(arg, "--minimal"))
3463                 DIFF_XDL_SET(options, NEED_MINIMAL);
3464         else if (!strcmp(arg, "--no-minimal"))
3465                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3466         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3467                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3468         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3469                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3470         else if (!strcmp(arg, "--ignore-space-at-eol"))
3471                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3472         else if (!strcmp(arg, "--patience"))
3473                 DIFF_XDL_SET(options, PATIENCE_DIFF);
3474         else if (!strcmp(arg, "--histogram"))
3475                 DIFF_XDL_SET(options, HISTOGRAM_DIFF);
3476
3477         /* flags options */
3478         else if (!strcmp(arg, "--binary")) {
3479                 options->output_format |= DIFF_FORMAT_PATCH;
3480                 DIFF_OPT_SET(options, BINARY);
3481         }
3482         else if (!strcmp(arg, "--full-index"))
3483                 DIFF_OPT_SET(options, FULL_INDEX);
3484         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3485                 DIFF_OPT_SET(options, TEXT);
3486         else if (!strcmp(arg, "-R"))
3487                 DIFF_OPT_SET(options, REVERSE_DIFF);
3488         else if (!strcmp(arg, "--find-copies-harder"))
3489                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3490         else if (!strcmp(arg, "--follow"))
3491                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3492         else if (!strcmp(arg, "--color"))
3493                 options->use_color = 1;
3494         else if (!prefixcmp(arg, "--color=")) {
3495                 int value = git_config_colorbool(NULL, arg+8);
3496                 if (value < 0)
3497                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3498                 options->use_color = value;
3499         }
3500         else if (!strcmp(arg, "--no-color"))
3501                 options->use_color = 0;
3502         else if (!strcmp(arg, "--color-words")) {
3503                 options->use_color = 1;
3504                 options->word_diff = DIFF_WORDS_COLOR;
3505         }
3506         else if (!prefixcmp(arg, "--color-words=")) {
3507                 options->use_color = 1;
3508                 options->word_diff = DIFF_WORDS_COLOR;
3509                 options->word_regex = arg + 14;
3510         }
3511         else if (!strcmp(arg, "--word-diff")) {
3512                 if (options->word_diff == DIFF_WORDS_NONE)
3513                         options->word_diff = DIFF_WORDS_PLAIN;
3514         }
3515         else if (!prefixcmp(arg, "--word-diff=")) {
3516                 const char *type = arg + 12;
3517                 if (!strcmp(type, "plain"))
3518                         options->word_diff = DIFF_WORDS_PLAIN;
3519                 else if (!strcmp(type, "color")) {
3520                         options->use_color = 1;
3521                         options->word_diff = DIFF_WORDS_COLOR;
3522                 }
3523                 else if (!strcmp(type, "porcelain"))
3524                         options->word_diff = DIFF_WORDS_PORCELAIN;
3525                 else if (!strcmp(type, "none"))
3526                         options->word_diff = DIFF_WORDS_NONE;
3527                 else
3528                         die("bad --word-diff argument: %s", type);
3529         }
3530         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3531                 if (options->word_diff == DIFF_WORDS_NONE)
3532                         options->word_diff = DIFF_WORDS_PLAIN;
3533                 options->word_regex = optarg;
3534                 return argcount;
3535         }
3536         else if (!strcmp(arg, "--exit-code"))
3537                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3538         else if (!strcmp(arg, "--quiet"))
3539                 DIFF_OPT_SET(options, QUICK);
3540         else if (!strcmp(arg, "--ext-diff"))
3541                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3542         else if (!strcmp(arg, "--no-ext-diff"))
3543                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3544         else if (!strcmp(arg, "--textconv"))
3545                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3546         else if (!strcmp(arg, "--no-textconv"))
3547                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3548         else if (!strcmp(arg, "--ignore-submodules")) {
3549                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3550                 handle_ignore_submodules_arg(options, "all");
3551         } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3552                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3553                 handle_ignore_submodules_arg(options, arg + 20);
3554         } else if (!strcmp(arg, "--submodule"))
3555                 DIFF_OPT_SET(options, SUBMODULE_LOG);
3556         else if (!prefixcmp(arg, "--submodule=")) {
3557                 if (!strcmp(arg + 12, "log"))
3558                         DIFF_OPT_SET(options, SUBMODULE_LOG);
3559         }
3560
3561         /* misc options */
3562         else if (!strcmp(arg, "-z"))
3563                 options->line_termination = 0;
3564         else if ((argcount = short_opt('l', av, &optarg))) {
3565                 options->rename_limit = strtoul(optarg, NULL, 10);
3566                 return argcount;
3567         }
3568         else if ((argcount = short_opt('S', av, &optarg))) {
3569                 options->pickaxe = optarg;
3570                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3571                 return argcount;
3572         } else if ((argcount = short_opt('G', av, &optarg))) {
3573                 options->pickaxe = optarg;
3574                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3575                 return argcount;
3576         }
3577         else if (!strcmp(arg, "--pickaxe-all"))
3578                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3579         else if (!strcmp(arg, "--pickaxe-regex"))
3580                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3581         else if ((argcount = short_opt('O', av, &optarg))) {
3582                 options->orderfile = optarg;
3583                 return argcount;
3584         }
3585         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3586                 options->filter = optarg;
3587                 return argcount;
3588         }
3589         else if (!strcmp(arg, "--abbrev"))
3590                 options->abbrev = DEFAULT_ABBREV;
3591         else if (!prefixcmp(arg, "--abbrev=")) {
3592                 options->abbrev = strtoul(arg + 9, NULL, 10);
3593                 if (options->abbrev < MINIMUM_ABBREV)
3594                         options->abbrev = MINIMUM_ABBREV;
3595                 else if (40 < options->abbrev)
3596                         options->abbrev = 40;
3597         }
3598         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3599                 options->a_prefix = optarg;
3600                 return argcount;
3601         }
3602         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3603                 options->b_prefix = optarg;
3604                 return argcount;
3605         }
3606         else if (!strcmp(arg, "--no-prefix"))
3607                 options->a_prefix = options->b_prefix = "";
3608         else if (opt_arg(arg, '\0', "inter-hunk-context",
3609                          &options->interhunkcontext))
3610                 ;
3611         else if (!strcmp(arg, "-W"))
3612                 DIFF_OPT_SET(options, FUNCCONTEXT);
3613         else if (!strcmp(arg, "--function-context"))
3614                 DIFF_OPT_SET(options, FUNCCONTEXT);
3615         else if (!strcmp(arg, "--no-function-context"))
3616                 DIFF_OPT_CLR(options, FUNCCONTEXT);
3617         else if ((argcount = parse_long_opt("output", av, &optarg))) {
3618                 options->file = fopen(optarg, "w");
3619                 if (!options->file)
3620                         die_errno("Could not open '%s'", optarg);
3621                 options->close_file = 1;
3622                 return argcount;
3623         } else
3624                 return 0;
3625         return 1;
3626 }
3627
3628 int parse_rename_score(const char **cp_p)
3629 {
3630         unsigned long num, scale;
3631         int ch, dot;
3632         const char *cp = *cp_p;
3633
3634         num = 0;
3635         scale = 1;
3636         dot = 0;
3637         for (;;) {
3638                 ch = *cp;
3639                 if ( !dot && ch == '.' ) {
3640                         scale = 1;
3641                         dot = 1;
3642                 } else if ( ch == '%' ) {
3643                         scale = dot ? scale*100 : 100;
3644                         cp++;   /* % is always at the end */
3645                         break;
3646                 } else if ( ch >= '0' && ch <= '9' ) {
3647                         if ( scale < 100000 ) {
3648                                 scale *= 10;
3649                                 num = (num*10) + (ch-'0');
3650                         }
3651                 } else {
3652                         break;
3653                 }
3654                 cp++;
3655         }
3656         *cp_p = cp;
3657
3658         /* user says num divided by scale and we say internally that
3659          * is MAX_SCORE * num / scale.
3660          */
3661         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3662 }
3663
3664 static int diff_scoreopt_parse(const char *opt)
3665 {
3666         int opt1, opt2, cmd;
3667
3668         if (*opt++ != '-')
3669                 return -1;
3670         cmd = *opt++;
3671         if (cmd == '-') {
3672                 /* convert the long-form arguments into short-form versions */
3673                 if (!prefixcmp(opt, "break-rewrites")) {
3674                         opt += strlen("break-rewrites");
3675                         if (*opt == 0 || *opt++ == '=')
3676                                 cmd = 'B';
3677                 } else if (!prefixcmp(opt, "find-copies")) {
3678                         opt += strlen("find-copies");
3679                         if (*opt == 0 || *opt++ == '=')
3680                                 cmd = 'C';
3681                 } else if (!prefixcmp(opt, "find-renames")) {
3682                         opt += strlen("find-renames");
3683                         if (*opt == 0 || *opt++ == '=')
3684                                 cmd = 'M';
3685                 }
3686         }
3687         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3688                 return -1; /* that is not a -M, -C nor -B option */
3689
3690         opt1 = parse_rename_score(&opt);
3691         if (cmd != 'B')
3692                 opt2 = 0;
3693         else {
3694                 if (*opt == 0)
3695                         opt2 = 0;
3696                 else if (*opt != '/')
3697                         return -1; /* we expect -B80/99 or -B80 */
3698                 else {
3699                         opt++;
3700                         opt2 = parse_rename_score(&opt);
3701                 }
3702         }
3703         if (*opt != 0)
3704                 return -1;
3705         return opt1 | (opt2 << 16);
3706 }
3707
3708 struct diff_queue_struct diff_queued_diff;
3709
3710 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3711 {
3712         if (queue->alloc <= queue->nr) {
3713                 queue->alloc = alloc_nr(queue->alloc);
3714                 queue->queue = xrealloc(queue->queue,
3715                                         sizeof(dp) * queue->alloc);
3716         }
3717         queue->queue[queue->nr++] = dp;
3718 }
3719
3720 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3721                                  struct diff_filespec *one,
3722                                  struct diff_filespec *two)
3723 {
3724         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3725         dp->one = one;
3726         dp->two = two;
3727         if (queue)
3728                 diff_q(queue, dp);
3729         return dp;
3730 }
3731
3732 void diff_free_filepair(struct diff_filepair *p)
3733 {
3734         free_filespec(p->one);
3735         free_filespec(p->two);
3736         free(p);
3737 }
3738
3739 /* This is different from find_unique_abbrev() in that
3740  * it stuffs the result with dots for alignment.
3741  */
3742 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3743 {
3744         int abblen;
3745         const char *abbrev;
3746         if (len == 40)
3747                 return sha1_to_hex(sha1);
3748
3749         abbrev = find_unique_abbrev(sha1, len);
3750         abblen = strlen(abbrev);
3751         if (abblen < 37) {
3752                 static char hex[41];
3753                 if (len < abblen && abblen <= len + 2)
3754                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3755                 else
3756                         sprintf(hex, "%s...", abbrev);
3757                 return hex;
3758         }
3759         return sha1_to_hex(sha1);
3760 }
3761
3762 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3763 {
3764         int line_termination = opt->line_termination;
3765         int inter_name_termination = line_termination ? '\t' : '\0';
3766         if (opt->output_prefix) {
3767                 struct strbuf *msg = NULL;
3768                 msg = opt->output_prefix(opt, opt->output_prefix_data);
3769                 fprintf(opt->file, "%s", msg->buf);
3770         }
3771
3772         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3773                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3774                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
3775                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3776         }
3777         if (p->score) {
3778                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3779                         inter_name_termination);
3780         } else {
3781                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3782         }
3783
3784         if (p->status == DIFF_STATUS_COPIED ||
3785             p->status == DIFF_STATUS_RENAMED) {
3786                 const char *name_a, *name_b;
3787                 name_a = p->one->path;
3788                 name_b = p->two->path;
3789                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3790                 write_name_quoted(name_a, opt->file, inter_name_termination);
3791                 write_name_quoted(name_b, opt->file, line_termination);
3792         } else {
3793                 const char *name_a, *name_b;
3794                 name_a = p->one->mode ? p->one->path : p->two->path;
3795                 name_b = NULL;
3796                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3797                 write_name_quoted(name_a, opt->file, line_termination);
3798         }
3799 }
3800
3801 int diff_unmodified_pair(struct diff_filepair *p)
3802 {
3803         /* This function is written stricter than necessary to support
3804          * the currently implemented transformers, but the idea is to
3805          * let transformers to produce diff_filepairs any way they want,
3806          * and filter and clean them up here before producing the output.
3807          */
3808         struct diff_filespec *one = p->one, *two = p->two;
3809
3810         if (DIFF_PAIR_UNMERGED(p))
3811                 return 0; /* unmerged is interesting */
3812
3813         /* deletion, addition, mode or type change
3814          * and rename are all interesting.
3815          */
3816         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3817             DIFF_PAIR_MODE_CHANGED(p) ||
3818             strcmp(one->path, two->path))
3819                 return 0;
3820
3821         /* both are valid and point at the same path.  that is, we are
3822          * dealing with a change.
3823          */
3824         if (one->sha1_valid && two->sha1_valid &&
3825             !hashcmp(one->sha1, two->sha1) &&
3826             !one->dirty_submodule && !two->dirty_submodule)
3827                 return 1; /* no change */
3828         if (!one->sha1_valid && !two->sha1_valid)
3829                 return 1; /* both look at the same file on the filesystem. */
3830         return 0;
3831 }
3832
3833 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3834 {
3835         if (diff_unmodified_pair(p))
3836                 return;
3837
3838         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3839             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3840                 return; /* no tree diffs in patch format */
3841
3842         run_diff(p, o);
3843 }
3844
3845 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3846                             struct diffstat_t *diffstat)
3847 {
3848         if (diff_unmodified_pair(p))
3849                 return;
3850
3851         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3852             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3853                 return; /* no useful stat for tree diffs */
3854
3855         run_diffstat(p, o, diffstat);
3856 }
3857
3858 static void diff_flush_checkdiff(struct diff_filepair *p,
3859                 struct diff_options *o)
3860 {
3861         if (diff_unmodified_pair(p))
3862                 return;
3863
3864         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3865             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3866                 return; /* nothing to check in tree diffs */
3867
3868         run_checkdiff(p, o);
3869 }
3870
3871 int diff_queue_is_empty(void)
3872 {
3873         struct diff_queue_struct *q = &diff_queued_diff;
3874         int i;
3875         for (i = 0; i < q->nr; i++)
3876                 if (!diff_unmodified_pair(q->queue[i]))
3877                         return 0;
3878         return 1;
3879 }
3880
3881 #if DIFF_DEBUG
3882 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
3883 {
3884         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
3885                 x, one ? one : "",
3886                 s->path,
3887                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
3888                 s->mode,
3889                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
3890         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
3891                 x, one ? one : "",
3892                 s->size, s->xfrm_flags);
3893 }
3894
3895 void diff_debug_filepair(const struct diff_filepair *p, int i)
3896 {
3897         diff_debug_filespec(p->one, i, "one");
3898         diff_debug_filespec(p->two, i, "two");
3899         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
3900                 p->score, p->status ? p->status : '?',
3901                 p->one->rename_used, p->broken_pair);
3902 }
3903
3904 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
3905 {
3906         int i;
3907         if (msg)
3908                 fprintf(stderr, "%s\n", msg);
3909         fprintf(stderr, "q->nr = %d\n", q->nr);
3910         for (i = 0; i < q->nr; i++) {
3911                 struct diff_filepair *p = q->queue[i];
3912                 diff_debug_filepair(p, i);
3913         }
3914 }
3915 #endif
3916
3917 static void diff_resolve_rename_copy(void)
3918 {
3919         int i;
3920         struct diff_filepair *p;
3921         struct diff_queue_struct *q = &diff_queued_diff;
3922
3923         diff_debug_queue("resolve-rename-copy", q);
3924
3925         for (i = 0; i < q->nr; i++) {
3926                 p = q->queue[i];
3927                 p->status = 0; /* undecided */
3928                 if (DIFF_PAIR_UNMERGED(p))
3929                         p->status = DIFF_STATUS_UNMERGED;
3930                 else if (!DIFF_FILE_VALID(p->one))
3931                         p->status = DIFF_STATUS_ADDED;
3932                 else if (!DIFF_FILE_VALID(p->two))
3933                         p->status = DIFF_STATUS_DELETED;
3934                 else if (DIFF_PAIR_TYPE_CHANGED(p))
3935                         p->status = DIFF_STATUS_TYPE_CHANGED;
3936
3937                 /* from this point on, we are dealing with a pair
3938                  * whose both sides are valid and of the same type, i.e.
3939                  * either in-place edit or rename/copy edit.
3940                  */
3941                 else if (DIFF_PAIR_RENAME(p)) {
3942                         /*
3943                          * A rename might have re-connected a broken
3944                          * pair up, causing the pathnames to be the
3945                          * same again. If so, that's not a rename at
3946                          * all, just a modification..
3947                          *
3948                          * Otherwise, see if this source was used for
3949                          * multiple renames, in which case we decrement
3950                          * the count, and call it a copy.
3951                          */
3952                         if (!strcmp(p->one->path, p->two->path))
3953                                 p->status = DIFF_STATUS_MODIFIED;
3954                         else if (--p->one->rename_used > 0)
3955                                 p->status = DIFF_STATUS_COPIED;
3956                         else
3957                                 p->status = DIFF_STATUS_RENAMED;
3958                 }
3959                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
3960                          p->one->mode != p->two->mode ||
3961                          p->one->dirty_submodule ||
3962                          p->two->dirty_submodule ||
3963                          is_null_sha1(p->one->sha1))
3964                         p->status = DIFF_STATUS_MODIFIED;
3965                 else {
3966                         /* This is a "no-change" entry and should not
3967                          * happen anymore, but prepare for broken callers.
3968                          */
3969                         error("feeding unmodified %s to diffcore",
3970                               p->one->path);
3971                         p->status = DIFF_STATUS_UNKNOWN;
3972                 }
3973         }
3974         diff_debug_queue("resolve-rename-copy done", q);
3975 }
3976
3977 static int check_pair_status(struct diff_filepair *p)
3978 {
3979         switch (p->status) {
3980         case DIFF_STATUS_UNKNOWN:
3981                 return 0;
3982         case 0:
3983                 die("internal error in diff-resolve-rename-copy");
3984         default:
3985                 return 1;
3986         }
3987 }
3988
3989 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
3990 {
3991         int fmt = opt->output_format;
3992
3993         if (fmt & DIFF_FORMAT_CHECKDIFF)
3994                 diff_flush_checkdiff(p, opt);
3995         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
3996                 diff_flush_raw(p, opt);
3997         else if (fmt & DIFF_FORMAT_NAME) {
3998                 const char *name_a, *name_b;
3999                 name_a = p->two->path;
4000                 name_b = NULL;
4001                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4002                 write_name_quoted(name_a, opt->file, opt->line_termination);
4003         }
4004 }
4005
4006 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4007 {
4008         if (fs->mode)
4009                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4010         else
4011                 fprintf(file, " %s ", newdelete);
4012         write_name_quoted(fs->path, file, '\n');
4013 }
4014
4015
4016 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4017                 const char *line_prefix)
4018 {
4019         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4020                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4021                         p->two->mode, show_name ? ' ' : '\n');
4022                 if (show_name) {
4023                         write_name_quoted(p->two->path, file, '\n');
4024                 }
4025         }
4026 }
4027
4028 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4029                         const char *line_prefix)
4030 {
4031         char *names = pprint_rename(p->one->path, p->two->path);
4032
4033         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4034         free(names);
4035         show_mode_change(file, p, 0, line_prefix);
4036 }
4037
4038 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4039 {
4040         FILE *file = opt->file;
4041         char *line_prefix = "";
4042
4043         if (opt->output_prefix) {
4044                 struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
4045                 line_prefix = buf->buf;
4046         }
4047
4048         switch(p->status) {
4049         case DIFF_STATUS_DELETED:
4050                 fputs(line_prefix, file);
4051                 show_file_mode_name(file, "delete", p->one);
4052                 break;
4053         case DIFF_STATUS_ADDED:
4054                 fputs(line_prefix, file);
4055                 show_file_mode_name(file, "create", p->two);
4056                 break;
4057         case DIFF_STATUS_COPIED:
4058                 fputs(line_prefix, file);
4059                 show_rename_copy(file, "copy", p, line_prefix);
4060                 break;
4061         case DIFF_STATUS_RENAMED:
4062                 fputs(line_prefix, file);
4063                 show_rename_copy(file, "rename", p, line_prefix);
4064                 break;
4065         default:
4066                 if (p->score) {
4067                         fprintf(file, "%s rewrite ", line_prefix);
4068                         write_name_quoted(p->two->path, file, ' ');
4069                         fprintf(file, "(%d%%)\n", similarity_index(p));
4070                 }
4071                 show_mode_change(file, p, !p->score, line_prefix);
4072                 break;
4073         }
4074 }
4075
4076 struct patch_id_t {
4077         git_SHA_CTX *ctx;
4078         int patchlen;
4079 };
4080
4081 static int remove_space(char *line, int len)
4082 {
4083         int i;
4084         char *dst = line;
4085         unsigned char c;
4086
4087         for (i = 0; i < len; i++)
4088                 if (!isspace((c = line[i])))
4089                         *dst++ = c;
4090
4091         return dst - line;
4092 }
4093
4094 static void patch_id_consume(void *priv, char *line, unsigned long len)
4095 {
4096         struct patch_id_t *data = priv;
4097         int new_len;
4098
4099         /* Ignore line numbers when computing the SHA1 of the patch */
4100         if (!prefixcmp(line, "@@ -"))
4101                 return;
4102
4103         new_len = remove_space(line, len);
4104
4105         git_SHA1_Update(data->ctx, line, new_len);
4106         data->patchlen += new_len;
4107 }
4108
4109 /* returns 0 upon success, and writes result into sha1 */
4110 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4111 {
4112         struct diff_queue_struct *q = &diff_queued_diff;
4113         int i;
4114         git_SHA_CTX ctx;
4115         struct patch_id_t data;
4116         char buffer[PATH_MAX * 4 + 20];
4117
4118         git_SHA1_Init(&ctx);
4119         memset(&data, 0, sizeof(struct patch_id_t));
4120         data.ctx = &ctx;
4121
4122         for (i = 0; i < q->nr; i++) {
4123                 xpparam_t xpp;
4124                 xdemitconf_t xecfg;
4125                 mmfile_t mf1, mf2;
4126                 struct diff_filepair *p = q->queue[i];
4127                 int len1, len2;
4128
4129                 memset(&xpp, 0, sizeof(xpp));
4130                 memset(&xecfg, 0, sizeof(xecfg));
4131                 if (p->status == 0)
4132                         return error("internal diff status error");
4133                 if (p->status == DIFF_STATUS_UNKNOWN)
4134                         continue;
4135                 if (diff_unmodified_pair(p))
4136                         continue;
4137                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4138                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4139                         continue;
4140                 if (DIFF_PAIR_UNMERGED(p))
4141                         continue;
4142
4143                 diff_fill_sha1_info(p->one);
4144                 diff_fill_sha1_info(p->two);
4145                 if (fill_mmfile(&mf1, p->one) < 0 ||
4146                                 fill_mmfile(&mf2, p->two) < 0)
4147                         return error("unable to read files to diff");
4148
4149                 len1 = remove_space(p->one->path, strlen(p->one->path));
4150                 len2 = remove_space(p->two->path, strlen(p->two->path));
4151                 if (p->one->mode == 0)
4152                         len1 = snprintf(buffer, sizeof(buffer),
4153                                         "diff--gita/%.*sb/%.*s"
4154                                         "newfilemode%06o"
4155                                         "---/dev/null"
4156                                         "+++b/%.*s",
4157                                         len1, p->one->path,
4158                                         len2, p->two->path,
4159                                         p->two->mode,
4160                                         len2, p->two->path);
4161                 else if (p->two->mode == 0)
4162                         len1 = snprintf(buffer, sizeof(buffer),
4163                                         "diff--gita/%.*sb/%.*s"
4164                                         "deletedfilemode%06o"
4165                                         "---a/%.*s"
4166                                         "+++/dev/null",
4167                                         len1, p->one->path,
4168                                         len2, p->two->path,
4169                                         p->one->mode,
4170                                         len1, p->one->path);
4171                 else
4172                         len1 = snprintf(buffer, sizeof(buffer),
4173                                         "diff--gita/%.*sb/%.*s"
4174                                         "---a/%.*s"
4175                                         "+++b/%.*s",
4176                                         len1, p->one->path,
4177                                         len2, p->two->path,
4178                                         len1, p->one->path,
4179                                         len2, p->two->path);
4180                 git_SHA1_Update(&ctx, buffer, len1);
4181
4182                 if (diff_filespec_is_binary(p->one) ||
4183                     diff_filespec_is_binary(p->two)) {
4184                         git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4185                         git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4186                         continue;
4187                 }
4188
4189                 xpp.flags = 0;
4190                 xecfg.ctxlen = 3;
4191                 xecfg.flags = 0;
4192                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4193                               &xpp, &xecfg);
4194         }
4195
4196         git_SHA1_Final(sha1, &ctx);
4197         return 0;
4198 }
4199
4200 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4201 {
4202         struct diff_queue_struct *q = &diff_queued_diff;
4203         int i;
4204         int result = diff_get_patch_id(options, sha1);
4205
4206         for (i = 0; i < q->nr; i++)
4207                 diff_free_filepair(q->queue[i]);
4208
4209         free(q->queue);
4210         DIFF_QUEUE_CLEAR(q);
4211
4212         return result;
4213 }
4214
4215 static int is_summary_empty(const struct diff_queue_struct *q)
4216 {
4217         int i;
4218
4219         for (i = 0; i < q->nr; i++) {
4220                 const struct diff_filepair *p = q->queue[i];
4221
4222                 switch (p->status) {
4223                 case DIFF_STATUS_DELETED:
4224                 case DIFF_STATUS_ADDED:
4225                 case DIFF_STATUS_COPIED:
4226                 case DIFF_STATUS_RENAMED:
4227                         return 0;
4228                 default:
4229                         if (p->score)
4230                                 return 0;
4231                         if (p->one->mode && p->two->mode &&
4232                             p->one->mode != p->two->mode)
4233                                 return 0;
4234                         break;
4235                 }
4236         }
4237         return 1;
4238 }
4239
4240 static const char rename_limit_warning[] =
4241 "inexact rename detection was skipped due to too many files.";
4242
4243 static const char degrade_cc_to_c_warning[] =
4244 "only found copies from modified paths due to too many files.";
4245
4246 static const char rename_limit_advice[] =
4247 "you may want to set your %s variable to at least "
4248 "%d and retry the command.";
4249
4250 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4251 {
4252         if (degraded_cc)
4253                 warning(degrade_cc_to_c_warning);
4254         else if (needed)
4255                 warning(rename_limit_warning);
4256         else
4257                 return;
4258         if (0 < needed && needed < 32767)
4259                 warning(rename_limit_advice, varname, needed);
4260 }
4261
4262 void diff_flush(struct diff_options *options)
4263 {
4264         struct diff_queue_struct *q = &diff_queued_diff;
4265         int i, output_format = options->output_format;
4266         int separator = 0;
4267         int dirstat_by_line = 0;
4268
4269         /*
4270          * Order: raw, stat, summary, patch
4271          * or:    name/name-status/checkdiff (other bits clear)
4272          */
4273         if (!q->nr)
4274                 goto free_queue;
4275
4276         if (output_format & (DIFF_FORMAT_RAW |
4277                              DIFF_FORMAT_NAME |
4278                              DIFF_FORMAT_NAME_STATUS |
4279                              DIFF_FORMAT_CHECKDIFF)) {
4280                 for (i = 0; i < q->nr; i++) {
4281                         struct diff_filepair *p = q->queue[i];
4282                         if (check_pair_status(p))
4283                                 flush_one_pair(p, options);
4284                 }
4285                 separator++;
4286         }
4287
4288         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4289                 dirstat_by_line = 1;
4290
4291         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4292             dirstat_by_line) {
4293                 struct diffstat_t diffstat;
4294
4295                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4296                 for (i = 0; i < q->nr; i++) {
4297                         struct diff_filepair *p = q->queue[i];
4298                         if (check_pair_status(p))
4299                                 diff_flush_stat(p, options, &diffstat);
4300                 }
4301                 if (output_format & DIFF_FORMAT_NUMSTAT)
4302                         show_numstat(&diffstat, options);
4303                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4304                         show_stats(&diffstat, options);
4305                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4306                         show_shortstats(&diffstat, options);
4307                 if (output_format & DIFF_FORMAT_DIRSTAT)
4308                         show_dirstat_by_line(&diffstat, options);
4309                 free_diffstat_info(&diffstat);
4310                 separator++;
4311         }
4312         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4313                 show_dirstat(options);
4314
4315         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4316                 for (i = 0; i < q->nr; i++) {
4317                         diff_summary(options, q->queue[i]);
4318                 }
4319                 separator++;
4320         }
4321
4322         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4323             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4324             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4325                 /*
4326                  * run diff_flush_patch for the exit status. setting
4327                  * options->file to /dev/null should be safe, becaue we
4328                  * aren't supposed to produce any output anyway.
4329                  */
4330                 if (options->close_file)
4331                         fclose(options->file);
4332                 options->file = fopen("/dev/null", "w");
4333                 if (!options->file)
4334                         die_errno("Could not open /dev/null");
4335                 options->close_file = 1;
4336                 for (i = 0; i < q->nr; i++) {
4337                         struct diff_filepair *p = q->queue[i];
4338                         if (check_pair_status(p))
4339                                 diff_flush_patch(p, options);
4340                         if (options->found_changes)
4341                                 break;
4342                 }
4343         }
4344
4345         if (output_format & DIFF_FORMAT_PATCH) {
4346                 if (separator) {
4347                         putc(options->line_termination, options->file);
4348                         if (options->stat_sep) {
4349                                 /* attach patch instead of inline */
4350                                 fputs(options->stat_sep, options->file);
4351                         }
4352                 }
4353
4354                 for (i = 0; i < q->nr; i++) {
4355                         struct diff_filepair *p = q->queue[i];
4356                         if (check_pair_status(p))
4357                                 diff_flush_patch(p, options);
4358                 }
4359         }
4360
4361         if (output_format & DIFF_FORMAT_CALLBACK)
4362                 options->format_callback(q, options, options->format_callback_data);
4363
4364         for (i = 0; i < q->nr; i++)
4365                 diff_free_filepair(q->queue[i]);
4366 free_queue:
4367         free(q->queue);
4368         DIFF_QUEUE_CLEAR(q);
4369         if (options->close_file)
4370                 fclose(options->file);
4371
4372         /*
4373          * Report the content-level differences with HAS_CHANGES;
4374          * diff_addremove/diff_change does not set the bit when
4375          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4376          */
4377         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4378                 if (options->found_changes)
4379                         DIFF_OPT_SET(options, HAS_CHANGES);
4380                 else
4381                         DIFF_OPT_CLR(options, HAS_CHANGES);
4382         }
4383 }
4384
4385 static void diffcore_apply_filter(const char *filter)
4386 {
4387         int i;
4388         struct diff_queue_struct *q = &diff_queued_diff;
4389         struct diff_queue_struct outq;
4390         DIFF_QUEUE_CLEAR(&outq);
4391
4392         if (!filter)
4393                 return;
4394
4395         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4396                 int found;
4397                 for (i = found = 0; !found && i < q->nr; i++) {
4398                         struct diff_filepair *p = q->queue[i];
4399                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4400                              ((p->score &&
4401                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4402                               (!p->score &&
4403                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4404                             ((p->status != DIFF_STATUS_MODIFIED) &&
4405                              strchr(filter, p->status)))
4406                                 found++;
4407                 }
4408                 if (found)
4409                         return;
4410
4411                 /* otherwise we will clear the whole queue
4412                  * by copying the empty outq at the end of this
4413                  * function, but first clear the current entries
4414                  * in the queue.
4415                  */
4416                 for (i = 0; i < q->nr; i++)
4417                         diff_free_filepair(q->queue[i]);
4418         }
4419         else {
4420                 /* Only the matching ones */
4421                 for (i = 0; i < q->nr; i++) {
4422                         struct diff_filepair *p = q->queue[i];
4423
4424                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4425                              ((p->score &&
4426                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4427                               (!p->score &&
4428                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4429                             ((p->status != DIFF_STATUS_MODIFIED) &&
4430                              strchr(filter, p->status)))
4431                                 diff_q(&outq, p);
4432                         else
4433                                 diff_free_filepair(p);
4434                 }
4435         }
4436         free(q->queue);
4437         *q = outq;
4438 }
4439
4440 /* Check whether two filespecs with the same mode and size are identical */
4441 static int diff_filespec_is_identical(struct diff_filespec *one,
4442                                       struct diff_filespec *two)
4443 {
4444         if (S_ISGITLINK(one->mode))
4445                 return 0;
4446         if (diff_populate_filespec(one, 0))
4447                 return 0;
4448         if (diff_populate_filespec(two, 0))
4449                 return 0;
4450         return !memcmp(one->data, two->data, one->size);
4451 }
4452
4453 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4454 {
4455         int i;
4456         struct diff_queue_struct *q = &diff_queued_diff;
4457         struct diff_queue_struct outq;
4458         DIFF_QUEUE_CLEAR(&outq);
4459
4460         for (i = 0; i < q->nr; i++) {
4461                 struct diff_filepair *p = q->queue[i];
4462
4463                 /*
4464                  * 1. Entries that come from stat info dirtiness
4465                  *    always have both sides (iow, not create/delete),
4466                  *    one side of the object name is unknown, with
4467                  *    the same mode and size.  Keep the ones that
4468                  *    do not match these criteria.  They have real
4469                  *    differences.
4470                  *
4471                  * 2. At this point, the file is known to be modified,
4472                  *    with the same mode and size, and the object
4473                  *    name of one side is unknown.  Need to inspect
4474                  *    the identical contents.
4475                  */
4476                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
4477                     !DIFF_FILE_VALID(p->two) ||
4478                     (p->one->sha1_valid && p->two->sha1_valid) ||
4479                     (p->one->mode != p->two->mode) ||
4480                     diff_populate_filespec(p->one, 1) ||
4481                     diff_populate_filespec(p->two, 1) ||
4482                     (p->one->size != p->two->size) ||
4483                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4484                         diff_q(&outq, p);
4485                 else {
4486                         /*
4487                          * The caller can subtract 1 from skip_stat_unmatch
4488                          * to determine how many paths were dirty only
4489                          * due to stat info mismatch.
4490                          */
4491                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4492                                 diffopt->skip_stat_unmatch++;
4493                         diff_free_filepair(p);
4494                 }
4495         }
4496         free(q->queue);
4497         *q = outq;
4498 }
4499
4500 static int diffnamecmp(const void *a_, const void *b_)
4501 {
4502         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4503         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4504         const char *name_a, *name_b;
4505
4506         name_a = a->one ? a->one->path : a->two->path;
4507         name_b = b->one ? b->one->path : b->two->path;
4508         return strcmp(name_a, name_b);
4509 }
4510
4511 void diffcore_fix_diff_index(struct diff_options *options)
4512 {
4513         struct diff_queue_struct *q = &diff_queued_diff;
4514         qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4515 }
4516
4517 void diffcore_std(struct diff_options *options)
4518 {
4519         if (options->skip_stat_unmatch)
4520                 diffcore_skip_stat_unmatch(options);
4521         if (!options->found_follow) {
4522                 /* See try_to_follow_renames() in tree-diff.c */
4523                 if (options->break_opt != -1)
4524                         diffcore_break(options->break_opt);
4525                 if (options->detect_rename)
4526                         diffcore_rename(options);
4527                 if (options->break_opt != -1)
4528                         diffcore_merge_broken();
4529         }
4530         if (options->pickaxe)
4531                 diffcore_pickaxe(options);
4532         if (options->orderfile)
4533                 diffcore_order(options->orderfile);
4534         if (!options->found_follow)
4535                 /* See try_to_follow_renames() in tree-diff.c */
4536                 diff_resolve_rename_copy();
4537         diffcore_apply_filter(options->filter);
4538
4539         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4540                 DIFF_OPT_SET(options, HAS_CHANGES);
4541         else
4542                 DIFF_OPT_CLR(options, HAS_CHANGES);
4543
4544         options->found_follow = 0;
4545 }
4546
4547 int diff_result_code(struct diff_options *opt, int status)
4548 {
4549         int result = 0;
4550
4551         diff_warn_rename_limit("diff.renamelimit",
4552                                opt->needed_rename_limit,
4553                                opt->degraded_cc_to_c);
4554         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4555             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4556                 return status;
4557         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4558             DIFF_OPT_TST(opt, HAS_CHANGES))
4559                 result |= 01;
4560         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4561             DIFF_OPT_TST(opt, CHECK_FAILED))
4562                 result |= 02;
4563         return result;
4564 }
4565
4566 int diff_can_quit_early(struct diff_options *opt)
4567 {
4568         return (DIFF_OPT_TST(opt, QUICK) &&
4569                 !opt->filter &&
4570                 DIFF_OPT_TST(opt, HAS_CHANGES));
4571 }
4572
4573 /*
4574  * Shall changes to this submodule be ignored?
4575  *
4576  * Submodule changes can be configured to be ignored separately for each path,
4577  * but that configuration can be overridden from the command line.
4578  */
4579 static int is_submodule_ignored(const char *path, struct diff_options *options)
4580 {
4581         int ignored = 0;
4582         unsigned orig_flags = options->flags;
4583         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4584                 set_diffopt_flags_from_submodule_config(options, path);
4585         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4586                 ignored = 1;
4587         options->flags = orig_flags;
4588         return ignored;
4589 }
4590
4591 void diff_addremove(struct diff_options *options,
4592                     int addremove, unsigned mode,
4593                     const unsigned char *sha1,
4594                     const char *concatpath, unsigned dirty_submodule)
4595 {
4596         struct diff_filespec *one, *two;
4597
4598         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4599                 return;
4600
4601         /* This may look odd, but it is a preparation for
4602          * feeding "there are unchanged files which should
4603          * not produce diffs, but when you are doing copy
4604          * detection you would need them, so here they are"
4605          * entries to the diff-core.  They will be prefixed
4606          * with something like '=' or '*' (I haven't decided
4607          * which but should not make any difference).
4608          * Feeding the same new and old to diff_change()
4609          * also has the same effect.
4610          * Before the final output happens, they are pruned after
4611          * merged into rename/copy pairs as appropriate.
4612          */
4613         if (DIFF_OPT_TST(options, REVERSE_DIFF))
4614                 addremove = (addremove == '+' ? '-' :
4615                              addremove == '-' ? '+' : addremove);
4616
4617         if (options->prefix &&
4618             strncmp(concatpath, options->prefix, options->prefix_length))
4619                 return;
4620
4621         one = alloc_filespec(concatpath);
4622         two = alloc_filespec(concatpath);
4623
4624         if (addremove != '+')
4625                 fill_filespec(one, sha1, mode);
4626         if (addremove != '-') {
4627                 fill_filespec(two, sha1, mode);
4628                 two->dirty_submodule = dirty_submodule;
4629         }
4630
4631         diff_queue(&diff_queued_diff, one, two);
4632         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4633                 DIFF_OPT_SET(options, HAS_CHANGES);
4634 }
4635
4636 void diff_change(struct diff_options *options,
4637                  unsigned old_mode, unsigned new_mode,
4638                  const unsigned char *old_sha1,
4639                  const unsigned char *new_sha1,
4640                  const char *concatpath,
4641                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4642 {
4643         struct diff_filespec *one, *two;
4644
4645         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4646             is_submodule_ignored(concatpath, options))
4647                 return;
4648
4649         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4650                 unsigned tmp;
4651                 const unsigned char *tmp_c;
4652                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4653                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4654                 tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4655                         new_dirty_submodule = tmp;
4656         }
4657
4658         if (options->prefix &&
4659             strncmp(concatpath, options->prefix, options->prefix_length))
4660                 return;
4661
4662         one = alloc_filespec(concatpath);
4663         two = alloc_filespec(concatpath);
4664         fill_filespec(one, old_sha1, old_mode);
4665         fill_filespec(two, new_sha1, new_mode);
4666         one->dirty_submodule = old_dirty_submodule;
4667         two->dirty_submodule = new_dirty_submodule;
4668
4669         diff_queue(&diff_queued_diff, one, two);
4670         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4671                 DIFF_OPT_SET(options, HAS_CHANGES);
4672 }
4673
4674 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4675 {
4676         struct diff_filepair *pair;
4677         struct diff_filespec *one, *two;
4678
4679         if (options->prefix &&
4680             strncmp(path, options->prefix, options->prefix_length))
4681                 return NULL;
4682
4683         one = alloc_filespec(path);
4684         two = alloc_filespec(path);
4685         pair = diff_queue(&diff_queued_diff, one, two);
4686         pair->is_unmerged = 1;
4687         return pair;
4688 }
4689
4690 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4691                 size_t *outsize)
4692 {
4693         struct diff_tempfile *temp;
4694         const char *argv[3];
4695         const char **arg = argv;
4696         struct child_process child;
4697         struct strbuf buf = STRBUF_INIT;
4698         int err = 0;
4699
4700         temp = prepare_temp_file(spec->path, spec);
4701         *arg++ = pgm;
4702         *arg++ = temp->name;
4703         *arg = NULL;
4704
4705         memset(&child, 0, sizeof(child));
4706         child.use_shell = 1;
4707         child.argv = argv;
4708         child.out = -1;
4709         if (start_command(&child)) {
4710                 remove_tempfile();
4711                 return NULL;
4712         }
4713
4714         if (strbuf_read(&buf, child.out, 0) < 0)
4715                 err = error("error reading from textconv command '%s'", pgm);
4716         close(child.out);
4717
4718         if (finish_command(&child) || err) {
4719                 strbuf_release(&buf);
4720                 remove_tempfile();
4721                 return NULL;
4722         }
4723         remove_tempfile();
4724
4725         return strbuf_detach(&buf, outsize);
4726 }
4727
4728 size_t fill_textconv(struct userdiff_driver *driver,
4729                      struct diff_filespec *df,
4730                      char **outbuf)
4731 {
4732         size_t size;
4733
4734         if (!driver || !driver->textconv) {
4735                 if (!DIFF_FILE_VALID(df)) {
4736                         *outbuf = "";
4737                         return 0;
4738                 }
4739                 if (diff_populate_filespec(df, 0))
4740                         die("unable to read files to diff");
4741                 *outbuf = df->data;
4742                 return df->size;
4743         }
4744
4745         if (driver->textconv_cache && df->sha1_valid) {
4746                 *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4747                                           &size);
4748                 if (*outbuf)
4749                         return size;
4750         }
4751
4752         *outbuf = run_textconv(driver->textconv, df, &size);
4753         if (!*outbuf)
4754                 die("unable to read files to diff");
4755
4756         if (driver->textconv_cache && df->sha1_valid) {
4757                 /* ignore errors, as we might be in a readonly repository */
4758                 notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4759                                 size);
4760                 /*
4761                  * we could save up changes and flush them all at the end,
4762                  * but we would need an extra call after all diffing is done.
4763                  * Since generating a cache entry is the slow path anyway,
4764                  * this extra overhead probably isn't a big deal.
4765                  */
4766                 notes_cache_write(driver->textconv_cache);
4767         }
4768
4769         return size;
4770 }