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authorJunio C Hamano <junkio@cox.net>2006-04-26 00:40:02 (GMT)
committerJunio C Hamano <junkio@cox.net>2006-04-26 00:40:02 (GMT)
commit61fa30972c45e73d39c81d27af9eeacbda7531c9 (patch)
tree56d9e8d5ff0f3da0a12b513a8432d0e33f2c4c2d
parent53dc3f3e8069283924fcb7f1d538e2d1b03ec3bb (diff)
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cache-tree: sort the subtree entries.
Not that this makes practical performance difference; the kernel tree for example has 200 or so directories that have subdirectory, and the largest ones have 57 of them (fs and drivers). With a test to apply 600 patches with git-apply and git-write-tree, this did not make more than one per-cent of a difference, but it is a good cleanup. Signed-off-by: Junio C Hamano <junkio@cox.net>
-rw-r--r--cache-tree.c92
1 files changed, 66 insertions, 26 deletions
diff --git a/cache-tree.c b/cache-tree.c
index 2146723..d8438d6 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -19,38 +19,75 @@ void cache_tree_free(struct cache_tree **it_p)
if (!it)
return;
for (i = 0; i < it->subtree_nr; i++)
- cache_tree_free(&it->down[i]->cache_tree);
+ if (it->down[i])
+ cache_tree_free(&it->down[i]->cache_tree);
free(it->down);
free(it);
*it_p = NULL;
}
+static int subtree_name_cmp(const char *one, int onelen,
+ const char *two, int twolen)
+{
+ if (onelen < twolen)
+ return -1;
+ if (twolen < onelen)
+ return 1;
+ return memcmp(one, two, onelen);
+}
+
+static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
+{
+ struct cache_tree_sub **down = it->down;
+ int lo, hi;
+ lo = 0;
+ hi = it->subtree_nr;
+ while (lo < hi) {
+ int mi = (lo + hi) / 2;
+ struct cache_tree_sub *mdl = down[mi];
+ int cmp = subtree_name_cmp(path, pathlen,
+ mdl->name, mdl->namelen);
+ if (!cmp)
+ return mi;
+ if (cmp < 0)
+ hi = mi;
+ else
+ lo = mi + 1;
+ }
+ return -lo-1;
+}
+
static struct cache_tree_sub *find_subtree(struct cache_tree *it,
const char *path,
int pathlen,
int create)
{
- int i;
struct cache_tree_sub *down;
- for (i = 0; i < it->subtree_nr; i++) {
- down = it->down[i];
- if (down->namelen == pathlen &&
- !memcmp(down->name, path, pathlen))
- return down;
- }
+ int pos = subtree_pos(it, path, pathlen);
+ if (0 <= pos)
+ return it->down[pos];
if (!create)
return NULL;
+
+ pos = -pos-1;
if (it->subtree_alloc <= it->subtree_nr) {
it->subtree_alloc = alloc_nr(it->subtree_alloc);
it->down = xrealloc(it->down, it->subtree_alloc *
sizeof(*it->down));
}
+ it->subtree_nr++;
+
down = xmalloc(sizeof(*down) + pathlen + 1);
- down->cache_tree = NULL; /* cache_tree(); */
+ down->cache_tree = NULL;
down->namelen = pathlen;
memcpy(down->name, path, pathlen);
- down->name[pathlen] = 0; /* not strictly needed */
- it->down[it->subtree_nr++] = down;
+ down->name[pathlen] = 0;
+
+ if (pos < it->subtree_nr)
+ memmove(it->down + pos + 1,
+ it->down + pos,
+ sizeof(down) * (it->subtree_nr - pos - 1));
+ it->down[pos] = down;
return down;
}
@@ -72,25 +109,21 @@ void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
slash = strchr(path, '/');
it->entry_count = -1;
if (!slash) {
- int i;
+ int pos;
namelen = strlen(path);
- for (i = 0; i < it->subtree_nr; i++) {
- if (it->down[i]->namelen == namelen &&
- !memcmp(it->down[i]->name, path, namelen))
- break;
- }
- if (i < it->subtree_nr) {
- cache_tree_free(&it->down[i]->cache_tree);
- free(it->down[i]);
+ pos = subtree_pos(it, path, namelen);
+ if (0 <= pos) {
+ cache_tree_free(&it->down[pos]->cache_tree);
+ free(it->down[pos]);
/* 0 1 2 3 4 5
* ^ ^subtree_nr = 6
- * i
+ * pos
* move 4 and 5 up one place (2 entries)
- * 2 = 6 - 3 - 1 = subtree_nr - i - 1
+ * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
*/
- memmove(it->down+i, it->down+i+1,
+ memmove(it->down+pos, it->down+pos+1,
sizeof(struct cache_tree_sub *) *
- (it->subtree_nr - i - 1));
+ (it->subtree_nr - pos - 1));
it->subtree_nr--;
}
return;
@@ -364,6 +397,12 @@ static void *write_one(struct cache_tree *it,
}
for (i = 0; i < it->subtree_nr; i++) {
struct cache_tree_sub *down = it->down[i];
+ if (i) {
+ struct cache_tree_sub *prev = it->down[i-1];
+ if (subtree_name_cmp(down->name, down->namelen,
+ prev->name, prev->namelen) <= 0)
+ die("fatal - unsorted cache subtree");
+ }
buffer = write_one(down->cache_tree, down->name, down->namelen,
buffer, size, offset);
}
@@ -435,14 +474,15 @@ static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
for (i = 0; i < subtree_nr; i++) {
/* read each subtree */
struct cache_tree *sub;
+ struct cache_tree_sub *subtree;
const char *name = buf;
int namelen;
sub = read_one(&buf, &size);
if (!sub)
goto free_return;
namelen = strlen(name);
- it->down[i] = find_subtree(it, name, namelen, 1);
- it->down[i]->cache_tree = sub;
+ subtree = find_subtree(it, name, namelen, 1);
+ subtree->cache_tree = sub;
}
if (subtree_nr != it->subtree_nr)
die("cache-tree: internal error");