From d9839e030592292267e6317fba308383e0012001 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 13 Apr 2005 09:57:30 -0700 Subject: [PATCH] Make "fsck-cache" use the same revision tracking structure as "rev-tree". This makes things a lot more efficient, and makes it trivial to do things like reachability analysis. Add command line flags to tell what the head is, and whether to warn about unreachable objects. --- fsck-cache.c | 209 ++++++++++++++++++++++++++++++++------------------- 1 file changed, 133 insertions(+), 76 deletions(-) diff --git a/fsck-cache.c b/fsck-cache.c index 2bb3a64a3..bb2b86761 100644 --- a/fsck-cache.c +++ b/fsck-cache.c @@ -3,114 +3,159 @@ #include #include -struct needs { - unsigned char parent[20]; - unsigned char needs[20]; - char tag[10]; +/* + * The low 16 bits of the "flags" field shows whether + * a commit is part of the path to the root for that + * parent. + * + * Bit 16 is an internal flag that we've seen the + * definition for this rev, and not just seen it as + * a parent target. + */ +#define MAX_COMMITS (16) +#define marked(rev) ((rev)->flags & 0xffff) +#define SEEN 0x10000 +#define USED 0x20000 +#define REACHABLE 0x40000 + +static int show_unreachable = 0; +static int head_supplied = 0; +static unsigned char head_sha1[20]; + +struct parent { + struct revision *parent; + struct parent *next; }; -struct seen { +struct revision { + unsigned int flags; unsigned char sha1[20]; - char tag[10]; - unsigned needed; + unsigned long date; + struct parent *parent; }; -static struct needs *needs; -static struct seen *seen; +static struct revision **revs; +static int nr_revs, rev_allocs; -static int nr_seen, alloc_seen, nr_needs, alloc_needs; - -/* - * These two functions build up a graph in memory about - * what objects we've referenced, and found, and types.. - */ -static int compare_seen(const void *s1, const void *s2) +static int find_rev(unsigned char *sha1) { - return memcmp(s1, s2, 20); -} + int first = 0, last = nr_revs; -static int lookup_seen(unsigned char *sha1, char *tag) -{ - int first = 0, last = nr_seen; - - while (last > first) { - int next = (last + first) / 2; - struct seen *s = seen + next; - int cmp = memcmp(sha1, s->sha1, 20); + while (first < last) { + int next = (first + last) / 2; + struct revision *rev = revs[next]; + int cmp; + cmp = memcmp(sha1, rev->sha1, 20); + if (!cmp) + return next; if (cmp < 0) { last = next; continue; } - if (cmp > 0) { - first = next+1; - continue; - } - if (strcmp(tag, s->tag)) - break; - s->needed++; - return 1; + first = next+1; + } + return -first-1; +} + +static struct revision *lookup_rev(unsigned char *sha1) +{ + int pos = find_rev(sha1); + struct revision *n; + + if (pos >= 0) + return revs[pos]; + + pos = -pos-1; + + if (rev_allocs == nr_revs) { + rev_allocs = alloc_nr(rev_allocs); + revs = realloc(revs, rev_allocs * sizeof(struct revision *)); + } + n = malloc(sizeof(struct revision)); + + n->flags = 0; + memcpy(n->sha1, sha1, 20); + n->parent = NULL; + + /* Insert it into the right place */ + memmove(revs + pos + 1, revs + pos, (nr_revs - pos) * sizeof(struct revision *)); + revs[pos] = n; + nr_revs++; + + return n; +} + +static struct revision *add_relationship(struct revision *rev, unsigned char *needs) +{ + struct revision *parent_rev = lookup_rev(needs); + struct parent **pp = &rev->parent, *p; + + while ((p = *pp) != NULL) { + if (p->parent == parent_rev) + return parent_rev; + pp = &p->next; + } + + p = malloc(sizeof(*p)); + p->parent = parent_rev; + p->next = NULL; + *pp = p; + return parent_rev; +} + +static void mark_reachable(struct revision *rev) +{ + struct parent *p = rev->parent; + + rev->flags |= REACHABLE | USED; + while (p) { + mark_reachable(p->parent); + p = p->next; } - return 0; } static void check_connectivity(void) { int i; - /* Sort the "seen" tags for quicker lookup */ - qsort(seen, nr_seen, sizeof(struct seen), compare_seen); + if (head_supplied) + mark_reachable(lookup_rev(head_sha1)); /* Look up all the requirements, warn about missing objects.. */ - for (i = 0; i < nr_needs; i++) { - struct needs *n = needs + i; - char hex[60]; + for (i = 0; i < nr_revs; i++) { + struct revision *rev = revs[i]; - if (lookup_seen(n->needs, n->tag)) + if (show_unreachable && !(rev->flags & REACHABLE)) { + printf("unreachable %s\n", sha1_to_hex(rev->sha1)); continue; - strcpy(hex, sha1_to_hex(n->parent)); - printf("missing %s: %s referenced by %s\n", n->tag, sha1_to_hex(n->needs), hex); - } - - /* Tell the user about things not referenced.. */ - for (i = 0; i < nr_seen; i++) { - struct seen *s = seen + i; + } - if (s->needed) - continue; - printf("unreferenced %s: %s\n", s->tag, sha1_to_hex(s->sha1)); + switch (rev->flags & (SEEN | USED)) { + case 0: + printf("bad %s\n", sha1_to_hex(rev->sha1)); + break; + case USED: + printf("missing %s\n", sha1_to_hex(rev->sha1)); + break; + case SEEN: + printf("dangling %s\n", sha1_to_hex(rev->sha1)); + break; + } } } static void mark_needs_sha1(unsigned char *parent, const char * tag, unsigned char *child) { - struct needs *n; - - if (nr_needs == alloc_needs) { - alloc_needs = alloc_nr(alloc_needs); - needs = realloc(needs, alloc_needs*sizeof(struct needs)); - } - n = needs + nr_needs; - nr_needs++; - memcpy(n->parent, parent, 20); - memcpy(n->needs, child, 20); - strncpy(n->tag, tag, sizeof(n->tag)); + struct revision * child_rev = add_relationship(lookup_rev(parent), child); + child_rev->flags |= USED; } static int mark_sha1_seen(unsigned char *sha1, char *tag) { - struct seen *s; + struct revision *rev = lookup_rev(sha1); - if (nr_seen == alloc_seen) { - alloc_seen = alloc_nr(alloc_seen); - seen = realloc(seen, alloc_seen*sizeof(struct seen)); - } - s = seen + nr_seen; - memset(s, 0, sizeof(*s)); - nr_seen++; - memcpy(s->sha1, sha1, 20); - strncpy(s->tag, tag, sizeof(s->tag)); - + rev->flags |= SEEN; return 0; } @@ -160,7 +205,7 @@ static int fsck_commit(unsigned char *sha1, void *data, unsigned long size) parents++; } if (!parents) - printf("root: %s\n", sha1_to_hex(sha1)); + printf("root %s\n", sha1_to_hex(sha1)); return 0; } @@ -237,8 +282,20 @@ int main(int argc, char **argv) int i; char *sha1_dir; - if (argc != 1) - usage("fsck-cache"); + for (i = 1; i < argc; i++) { + if (!strcmp(argv[i], "--unreachable")) { + show_unreachable = 1; + continue; + } + if (!get_sha1_hex(argv[i], head_sha1)) { + head_supplied = 1; + continue; + } + usage("fsck-cache [[--unreachable] ]"); + } + if (show_unreachable && !head_supplied) + usage("unable to do reachability checks without a head"); + sha1_dir = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT; for (i = 0; i < 256; i++) { static char dir[4096]; -- 2.26.2