Remove hash in git-describe in favor of util slot.
authorShawn O. Pearce <spearce@spearce.org>
Mon, 15 Jan 2007 03:16:55 +0000 (22:16 -0500)
committerJunio C Hamano <junkio@cox.net>
Mon, 15 Jan 2007 05:17:27 +0000 (21:17 -0800)
Currently we don't use the util field of struct commit but we want
fast access to the highest priority name that references any given
commit object during our matching loop.  A really simple approach
is to just store the name directly in the util field.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
builtin-describe.c

index e38c899251c7959720bc45cd0c63ef643d6b9580..e7b8f95c81eb844d152b58e539e586ab4ddada41 100644 (file)
@@ -16,60 +16,27 @@ static int tags;    /* But allow any tags if --tags is specified */
 static int abbrev = DEFAULT_ABBREV;
 static int max_candidates = 10;
 
-static unsigned int names[256], allocs[256];
-static struct commit_name {
-       struct commit *commit;
+struct commit_name {
        int prio; /* annotated tag = 2, tag = 1, head = 0 */
        char path[FLEX_ARRAY]; /* more */
-} **name_array[256];
+};
 static const char *prio_names[] = {
        "head", "lightweight", "annotated",
 };
 
-static struct commit_name *match(struct commit *cmit)
-{
-       unsigned char level0 = cmit->object.sha1[0];
-       struct commit_name **p = name_array[level0];
-       unsigned int hi = names[level0];
-       unsigned int lo = 0;
-
-       while (lo < hi) {
-               unsigned int mi = (lo + hi) / 2;
-               int cmp = hashcmp(p[mi]->commit->object.sha1,
-                       cmit->object.sha1);
-               if (!cmp) {
-                       while (mi && p[mi - 1]->commit == cmit)
-                               mi--;
-                       return p[mi];
-               }
-               if (cmp > 0)
-                       hi = mi;
-               else
-                       lo = mi+1;
-       }
-       return NULL;
-}
-
 static void add_to_known_names(const char *path,
                               struct commit *commit,
                               int prio)
 {
-       int idx;
-       int len = strlen(path)+1;
-       struct commit_name *name = xmalloc(sizeof(struct commit_name) + len);
-       unsigned char m = commit->object.sha1[0];
-
-       name->commit = commit;
-       name->prio = prio;
-       memcpy(name->path, path, len);
-       idx = names[m];
-       if (idx >= allocs[m]) {
-               allocs[m] = (idx + 50) * 3 / 2;
-               name_array[m] = xrealloc(name_array[m],
-                       allocs[m] * sizeof(*name_array));
+       struct commit_name *e = commit->util;
+       if (!e || e->prio < prio) {
+               size_t len = strlen(path)+1;
+               free(e);
+               e = xmalloc(sizeof(struct commit_name) + len);
+               e->prio = prio;
+               memcpy(e->path, path, len);
+               commit->util = e;
        }
-       name_array[m][idx] = name;
-       names[m] = ++idx;
 }
 
 static int get_name(const char *path, const unsigned char *sha1, int flag, void *cb_data)
@@ -104,21 +71,6 @@ static int get_name(const char *path, const unsigned char *sha1, int flag, void
        return 0;
 }
 
-static int compare_names(const void *_a, const void *_b)
-{
-       struct commit_name *a = *(struct commit_name **)_a;
-       struct commit_name *b = *(struct commit_name **)_b;
-       unsigned long a_date = a->commit->date;
-       unsigned long b_date = b->commit->date;
-       int cmp = hashcmp(a->commit->object.sha1, b->commit->object.sha1);
-
-       if (cmp)
-               return cmp;
-       if (a->prio != b->prio)
-               return b->prio - a->prio;
-       return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
-}
-
 struct possible_tag {
        struct commit_name *name;
        int depth;
@@ -158,15 +110,11 @@ static void describe(const char *arg, int last_one)
                die("%s is not a valid '%s' object", arg, commit_type);
 
        if (!initialized) {
-               unsigned int m;
                initialized = 1;
                for_each_ref(get_name, NULL);
-               for (m = 0; m < ARRAY_SIZE(name_array); m++)
-                       qsort(name_array[m], names[m],
-                               sizeof(*name_array[m]), compare_names);
        }
 
-       n = match(cmit);
+       n = cmit->util;
        if (n) {
                printf("%s\n", n->path);
                return;
@@ -182,7 +130,7 @@ static void describe(const char *arg, int last_one)
                struct commit *c = pop_commit(&list);
                struct commit_list *parents = c->parents;
                seen_commits++;
-               n = match(c);
+               n = c->util;
                if (n) {
                        if (match_cnt < max_candidates) {
                                struct possible_tag *t = &all_matches[match_cnt++];