sha1_name.c: prepare to make get_tree_entry() reusable from others.
[gitweb.git] / pack-objects.c
index d7ba938af734f3ece9ff4f7060f32b8406f1827f..09f4f2c944d95bb145823c0b07f4a7f302bcab1f 100644 (file)
@@ -1,5 +1,9 @@
 #include "cache.h"
 #include "object.h"
+#include "blob.h"
+#include "commit.h"
+#include "tag.h"
+#include "tree.h"
 #include "delta.h"
 #include "pack.h"
 #include "csum-file.h"
@@ -449,7 +453,7 @@ static void rehash_objects(void)
        if (object_ix_hashsz < 1024)
                object_ix_hashsz = 1024;
        object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
-       object_ix = memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
+       memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
        for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
                int ix = locate_object_entry_hash(oe->sha1);
                if (0 <= ix)
@@ -501,21 +505,6 @@ static unsigned name_hash(struct name_path *path, const char *name)
         * but close enough.
         */
        hash = (name_hash<<DIRBITS) | (hash & ((1U<<DIRBITS )-1));
-
-       if (0) { /* debug */
-               n = name + strlen(name);
-               if (n != name && n[-1] == '\n')
-                       n--;
-               while (name <= --n)
-                       fputc(*n, stderr);
-               for (p = path; p; p = p->up) {
-                       fputc('/', stderr);
-                       n = p->elem + p->len;
-                       while (p->elem <= --n)
-                               fputc(*n, stderr);
-               }
-               fprintf(stderr, "\t%08x\n", hash);
-       }
        return hash;
 }
 
@@ -583,56 +572,254 @@ static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclud
        return status;
 }
 
-static void add_pbase_tree(struct tree_desc *tree, struct name_path *up)
+struct pbase_tree_cache {
+       unsigned char sha1[20];
+       int ref;
+       int temporary;
+       void *tree_data;
+       unsigned long tree_size;
+};
+
+static struct pbase_tree_cache *(pbase_tree_cache[256]);
+static int pbase_tree_cache_ix(const unsigned char *sha1)
+{
+       return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
+}
+static int pbase_tree_cache_ix_incr(int ix)
+{
+       return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
+}
+
+static struct pbase_tree {
+       struct pbase_tree *next;
+       /* This is a phony "cache" entry; we are not
+        * going to evict it nor find it through _get()
+        * mechanism -- this is for the toplevel node that
+        * would almost always change with any commit.
+        */
+       struct pbase_tree_cache pcache;
+} *pbase_tree;
+
+static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
+{
+       struct pbase_tree_cache *ent, *nent;
+       void *data;
+       unsigned long size;
+       char type[20];
+       int neigh;
+       int my_ix = pbase_tree_cache_ix(sha1);
+       int available_ix = -1;
+
+       /* pbase-tree-cache acts as a limited hashtable.
+        * your object will be found at your index or within a few
+        * slots after that slot if it is cached.
+        */
+       for (neigh = 0; neigh < 8; neigh++) {
+               ent = pbase_tree_cache[my_ix];
+               if (ent && !memcmp(ent->sha1, sha1, 20)) {
+                       ent->ref++;
+                       return ent;
+               }
+               else if (((available_ix < 0) && (!ent || !ent->ref)) ||
+                        ((0 <= available_ix) &&
+                         (!ent && pbase_tree_cache[available_ix])))
+                       available_ix = my_ix;
+               if (!ent)
+                       break;
+               my_ix = pbase_tree_cache_ix_incr(my_ix);
+       }
+
+       /* Did not find one.  Either we got a bogus request or
+        * we need to read and perhaps cache.
+        */
+       data = read_sha1_file(sha1, type, &size);
+       if (!data)
+               return NULL;
+       if (strcmp(type, tree_type)) {
+               free(data);
+               return NULL;
+       }
+
+       /* We need to either cache or return a throwaway copy */
+
+       if (available_ix < 0)
+               ent = NULL;
+       else {
+               ent = pbase_tree_cache[available_ix];
+               my_ix = available_ix;
+       }
+
+       if (!ent) {
+               nent = xmalloc(sizeof(*nent));
+               nent->temporary = (available_ix < 0);
+       }
+       else {
+               /* evict and reuse */
+               free(ent->tree_data);
+               nent = ent;
+       }
+       memcpy(nent->sha1, sha1, 20);
+       nent->tree_data = data;
+       nent->tree_size = size;
+       nent->ref = 1;
+       if (!nent->temporary)
+               pbase_tree_cache[my_ix] = nent;
+       return nent;
+}
+
+static void pbase_tree_put(struct pbase_tree_cache *cache)
+{
+       if (!cache->temporary) {
+               cache->ref--;
+               return;
+       }
+       free(cache->tree_data);
+       free(cache);
+}
+
+static int name_cmp_len(const char *name)
+{
+       int i;
+       for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
+               ;
+       return i;
+}
+
+static void add_pbase_object(struct tree_desc *tree,
+                            struct name_path *up,
+                            const char *name,
+                            int cmplen)
 {
        while (tree->size) {
                const unsigned char *sha1;
-               const char *name;
-               unsigned mode, hash;
+               const char *entry_name;
+               int entry_len;
+               unsigned mode;
                unsigned long size;
                char type[20];
 
-               sha1 = tree_entry_extract(tree, &name, &mode);
+               sha1 = tree_entry_extract(tree, &entry_name, &mode);
                update_tree_entry(tree);
-               if (!has_sha1_file(sha1))
-                       continue;
-               if (sha1_object_info(sha1, type, &size))
+               entry_len = strlen(entry_name);
+               if (entry_len != cmplen ||
+                   memcmp(entry_name, name, cmplen) ||
+                   !has_sha1_file(sha1) ||
+                   sha1_object_info(sha1, type, &size))
                        continue;
-
-               hash = name_hash(up, name);
-               if (!add_object_entry(sha1, hash, 1))
-                       continue;
-
-               if (!strcmp(type, "tree")) {
+               if (name[cmplen] != '/') {
+                       unsigned hash = name_hash(up, name);
+                       add_object_entry(sha1, hash, 1);
+                       return;
+               }
+               if (!strcmp(type, tree_type)) {
                        struct tree_desc sub;
-                       void *elem;
                        struct name_path me;
+                       struct pbase_tree_cache *tree;
+                       const char *down = name+cmplen+1;
+                       int downlen = name_cmp_len(down);
+
+                       tree = pbase_tree_get(sha1);
+                       if (!tree)
+                               return;
+                       sub.buf = tree->tree_data;
+                       sub.size = tree->tree_size;
+
+                       me.up = up;
+                       me.elem = entry_name;
+                       me.len = entry_len;
+                       add_pbase_object(&sub, &me, down, downlen);
+                       pbase_tree_put(tree);
+               }
+       }
+}
 
-                       elem = read_sha1_file(sha1, type, &sub.size);
-                       sub.buf = elem;
-                       if (sub.buf) {
-                               me.up = up;
-                               me.elem = name;
-                               me.len = strlen(name);
-                               add_pbase_tree(&sub, &me);
-                               free(elem);
-                       }
+static unsigned *done_pbase_paths;
+static int done_pbase_paths_num;
+static int done_pbase_paths_alloc;
+static int done_pbase_path_pos(unsigned hash)
+{
+       int lo = 0;
+       int hi = done_pbase_paths_num;
+       while (lo < hi) {
+               int mi = (hi + lo) / 2;
+               if (done_pbase_paths[mi] == hash)
+                       return mi;
+               if (done_pbase_paths[mi] < hash)
+                       hi = mi;
+               else
+                       lo = mi + 1;
+       }
+       return -lo-1;
+}
+
+static int check_pbase_path(unsigned hash)
+{
+       int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
+       if (0 <= pos)
+               return 1;
+       pos = -pos - 1;
+       if (done_pbase_paths_alloc <= done_pbase_paths_num) {
+               done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
+               done_pbase_paths = xrealloc(done_pbase_paths,
+                                           done_pbase_paths_alloc *
+                                           sizeof(unsigned));
+       }
+       done_pbase_paths_num++;
+       if (pos < done_pbase_paths_num)
+               memmove(done_pbase_paths + pos + 1,
+                       done_pbase_paths + pos,
+                       (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
+       done_pbase_paths[pos] = hash;
+       return 0;
+}
+
+static void add_preferred_base_object(char *name, unsigned hash)
+{
+       struct pbase_tree *it;
+       int cmplen = name_cmp_len(name);
+
+       if (check_pbase_path(hash))
+               return;
+
+       for (it = pbase_tree; it; it = it->next) {
+               if (cmplen == 0) {
+                       hash = name_hash(NULL, "");
+                       add_object_entry(it->pcache.sha1, hash, 1);
+               }
+               else {
+                       struct tree_desc tree;
+                       tree.buf = it->pcache.tree_data;
+                       tree.size = it->pcache.tree_size;
+                       add_pbase_object(&tree, NULL, name, cmplen);
                }
        }
 }
 
 static void add_preferred_base(unsigned char *sha1)
 {
-       struct tree_desc tree;
-       void *elem;
+       struct pbase_tree *it;
+       void *data;
+       unsigned long size;
+       unsigned char tree_sha1[20];
 
-       elem = read_object_with_reference(sha1, "tree", &tree.size, NULL);
-       tree.buf = elem;
-       if (!tree.buf)
+       data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
+       if (!data)
                return;
-       if (add_object_entry(sha1, name_hash(NULL, ""), 1))
-               add_pbase_tree(&tree, NULL);
-       free(elem);
+
+       for (it = pbase_tree; it; it = it->next) {
+               if (!memcmp(it->pcache.sha1, tree_sha1, 20)) {
+                       free(data);
+                       return;
+               }
+       }
+
+       it = xcalloc(1, sizeof(*it));
+       it->next = pbase_tree;
+       pbase_tree = it;
+
+       memcpy(it->pcache.sha1, tree_sha1, 20);
+       it->pcache.tree_data = data;
+       it->pcache.tree_size = size;
 }
 
 static void check_object(struct object_entry *entry)
@@ -684,13 +871,13 @@ static void check_object(struct object_entry *entry)
                die("unable to get type of object %s",
                    sha1_to_hex(entry->sha1));
 
-       if (!strcmp(type, "commit")) {
+       if (!strcmp(type, commit_type)) {
                entry->type = OBJ_COMMIT;
-       } else if (!strcmp(type, "tree")) {
+       } else if (!strcmp(type, tree_type)) {
                entry->type = OBJ_TREE;
-       } else if (!strcmp(type, "blob")) {
+       } else if (!strcmp(type, blob_type)) {
                entry->type = OBJ_BLOB;
-       } else if (!strcmp(type, "tag")) {
+       } else if (!strcmp(type, tag_type)) {
                entry->type = OBJ_TAG;
        } else
                die("unable to pack object %s of type %s",
@@ -1047,6 +1234,7 @@ int main(int argc, char **argv)
        char line[PATH_MAX + 20];
        int window = 10, depth = 10, pack_to_stdout = 0;
        struct object_entry **list;
+       int num_preferred_base = 0;
        int i;
 
        setup_git_directory();
@@ -1112,6 +1300,7 @@ int main(int argc, char **argv)
 
        for (;;) {
                unsigned char sha1[20];
+               unsigned hash;
 
                if (!fgets(line, sizeof(line), stdin)) {
                        if (feof(stdin))
@@ -1128,12 +1317,15 @@ int main(int argc, char **argv)
                        if (get_sha1_hex(line+1, sha1))
                                die("expected edge sha1, got garbage:\n %s",
                                    line+1);
-                       add_preferred_base(sha1);
+                       if (num_preferred_base++ < window)
+                               add_preferred_base(sha1);
                        continue;
                }
                if (get_sha1_hex(line, sha1))
                        die("expected sha1, got garbage:\n %s", line);
-               add_object_entry(sha1, name_hash(NULL, line+41), 0);
+               hash = name_hash(NULL, line+41);
+               add_preferred_base_object(line+41, hash);
+               add_object_entry(sha1, hash, 0);
        }
        if (progress)
                fprintf(stderr, "Done counting %d objects.\n", nr_objects);