speed up alt_odb_usable() with many alternates

[thirdparty/git.git] / object-file.c

diff --git a/object-file.c b/object-file.c
index f233b440b22c061cbdac1db019b1e8b58c093324..a13f49b1920c2eb43042fea8cdd9ddfdc2b9b965 100644 (file)
--- a/object-file.c
+++ b/object-file.c
@@ -517,9 +517,9 @@ const char *loose_object_path(struct repository *r, struct strbuf *buf,
  */
 static int alt_odb_usable(struct raw_object_store *o,
                          struct strbuf *path,
-                         const char *normalized_objdir)
+                         const char *normalized_objdir, khiter_t *pos)
 {
-       struct object_directory *odb;
+       int r;
 
        /* Detect cases where alternate disappeared */
        if (!is_directory(path->buf)) {
@@ -533,14 +533,20 @@ static int alt_odb_usable(struct raw_object_store *o,
         * Prevent the common mistake of listing the same
         * thing twice, or object directory itself.
         */
-       for (odb = o->odb; odb; odb = odb->next) {
-               if (!fspathcmp(path->buf, odb->path))
-                       return 0;
+       if (!o->odb_by_path) {
+               khiter_t p;
+
+               o->odb_by_path = kh_init_odb_path_map();
+               assert(!o->odb->next);
+               p = kh_put_odb_path_map(o->odb_by_path, o->odb->path, &r);
+               assert(r == 1); /* never used */
+               kh_value(o->odb_by_path, p) = o->odb;
        }
-       if (!fspathcmp(path->buf, normalized_objdir))
+       if (fspatheq(path->buf, normalized_objdir))
                return 0;
-
-       return 1;
+       *pos = kh_put_odb_path_map(o->odb_by_path, path->buf, &r);
+       /* r: 0 = exists, 1 = never used, 2 = deleted */
+       return r == 0 ? 0 : 1;
 }
 
 /*
@@ -566,6 +572,7 @@ static int link_alt_odb_entry(struct repository *r, const char *entry,
 {
        struct object_directory *ent;
        struct strbuf pathbuf = STRBUF_INIT;
+       khiter_t pos;
 
        if (!is_absolute_path(entry) && relative_base) {
                strbuf_realpath(&pathbuf, relative_base, 1);
@@ -587,23 +594,25 @@ static int link_alt_odb_entry(struct repository *r, const char *entry,
        while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
                strbuf_setlen(&pathbuf, pathbuf.len - 1);
 
-       if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir)) {
+       if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir, &pos)) {
                strbuf_release(&pathbuf);
                return -1;
        }
 
        CALLOC_ARRAY(ent, 1);
-       ent->path = xstrdup(pathbuf.buf);
+       /* pathbuf.buf is already in r->objects->odb_by_path */
+       ent->path = strbuf_detach(&pathbuf, NULL);
 
        /* add the alternate entry */
        *r->objects->odb_tail = ent;
        r->objects->odb_tail = &(ent->next);
        ent->next = NULL;
+       assert(r->objects->odb_by_path);
+       kh_value(r->objects->odb_by_path, pos) = ent;
 
        /* recursively add alternates */
-       read_info_alternates(r, pathbuf.buf, depth + 1);
+       read_info_alternates(r, ent->path, depth + 1);
 
-       strbuf_release(&pathbuf);
        return 0;
 }