Update grep internal for grepping only in head/body

This further updates the built-in grep engine so that we can say
something like "this pattern should match only in head".  This
can be used to simplify grepping in the log messages.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/grep.c b/grep.c
index 61db6e199cfed45601dacc4e798f6eb7801620e5..cc8d6846a59563b6b902f576262ec97b73f01562 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -43,6 +43,8 @@ static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
        p = *list;
        switch (p->token) {
        case GREP_PATTERN: /* atom */
+       case GREP_PATTERN_HEAD:
+       case GREP_PATTERN_BODY:
                x = xcalloc(1, sizeof (struct grep_expr));
                x->node = GREP_NODE_ATOM;
                x->u.atom = p;
@@ -141,10 +143,16 @@ void compile_grep_patterns(struct grep_opt *opt)
 
        /* First compile regexps */
        for (p = opt->pattern_list; p; p = p->next) {
-               if (p->token == GREP_PATTERN)
+               switch (p->token) {
+               case GREP_PATTERN: /* atom */
+               case GREP_PATTERN_HEAD:
+               case GREP_PATTERN_BODY:
                        compile_regexp(p, opt);
-               else
+                       break;
+               default:
                        opt->extended = 1;
+                       break;
+               }
        }
 
        if (!opt->extended)
@@ -210,12 +218,16 @@ static int fixmatch(const char *pattern, char *line, regmatch_t *match)
        }
 }
 
-static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol)
+static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol, enum grep_context ctx)
 {
        int hit = 0;
        int at_true_bol = 1;
        regmatch_t pmatch[10];
 
+       if ((p->token != GREP_PATTERN) &&
+           ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
+               return 0;
+
  again:
        if (!opt->fixed) {
                regex_t *exp = &p->regexp;
@@ -262,37 +274,40 @@ static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol
 
 static int match_expr_eval(struct grep_opt *opt,
                           struct grep_expr *x,
-                          char *bol, char *eol)
+                          char *bol, char *eol,
+                          enum grep_context ctx)
 {
        switch (x->node) {
        case GREP_NODE_ATOM:
-               return match_one_pattern(opt, x->u.atom, bol, eol);
+               return match_one_pattern(opt, x->u.atom, bol, eol, ctx);
                break;
        case GREP_NODE_NOT:
-               return !match_expr_eval(opt, x->u.unary, bol, eol);
+               return !match_expr_eval(opt, x->u.unary, bol, eol, ctx);
        case GREP_NODE_AND:
-               return (match_expr_eval(opt, x->u.binary.left, bol, eol) &&
-                       match_expr_eval(opt, x->u.binary.right, bol, eol));
+               return (match_expr_eval(opt, x->u.binary.left, bol, eol, ctx) &&
+                       match_expr_eval(opt, x->u.binary.right, bol, eol, ctx));
        case GREP_NODE_OR:
-               return (match_expr_eval(opt, x->u.binary.left, bol, eol) ||
-                       match_expr_eval(opt, x->u.binary.right, bol, eol));
+               return (match_expr_eval(opt, x->u.binary.left, bol, eol, ctx) ||
+                       match_expr_eval(opt, x->u.binary.right, bol, eol, ctx));
        }
        die("Unexpected node type (internal error) %d\n", x->node);
 }
 
-static int match_expr(struct grep_opt *opt, char *bol, char *eol)
+static int match_expr(struct grep_opt *opt, char *bol, char *eol,
+                     enum grep_context ctx)
 {
        struct grep_expr *x = opt->pattern_expression;
-       return match_expr_eval(opt, x, bol, eol);
+       return match_expr_eval(opt, x, bol, eol, ctx);
 }
 
-static int match_line(struct grep_opt *opt, char *bol, char *eol)
+static int match_line(struct grep_opt *opt, char *bol, char *eol,
+                     enum grep_context ctx)
 {
        struct grep_pat *p;
        if (opt->extended)
-               return match_expr(opt, bol, eol);
+               return match_expr(opt, bol, eol, ctx);
        for (p = opt->pattern_list; p; p = p->next) {
-               if (match_one_pattern(opt, p, bol, eol))
+               if (match_one_pattern(opt, p, bol, eol, ctx))
                        return 1;
        }
        return 0;
@@ -312,6 +327,7 @@ int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long
        int binary_match_only = 0;
        const char *hunk_mark = "";
        unsigned count = 0;
+       enum grep_context ctx = GREP_CONTEXT_HEAD;
 
        if (buffer_is_binary(buf, size)) {
                switch (opt->binary) {
@@ -339,7 +355,10 @@ int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long
                ch = *eol;
                *eol = 0;
 
-               hit = match_line(opt, bol, eol);
+               if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
+                       ctx = GREP_CONTEXT_BODY;
+
+               hit = match_line(opt, bol, eol, ctx);
                *eol = ch;
 
                /* "grep -v -e foo -e bla" should list lines

diff --git a/grep.h b/grep.h
index 80122b05df9b6bee0f89cecf99cf4303f0833af4..0b503ea6657692672c3365f3090151cc5e9e6681 100644 (file)
--- a/grep.h
+++ b/grep.h
@@ -3,6 +3,8 @@
 
 enum grep_pat_token {
        GREP_PATTERN,
+       GREP_PATTERN_HEAD,
+       GREP_PATTERN_BODY,
        GREP_AND,
        GREP_OPEN_PAREN,
        GREP_CLOSE_PAREN,
@@ -10,6 +12,11 @@ enum grep_pat_token {
        GREP_OR,
 };
 
+enum grep_context {
+       GREP_CONTEXT_HEAD,
+       GREP_CONTEXT_BODY,
+};
+
 struct grep_pat {
        struct grep_pat *next;
        const char *origin;