Add a HOWTO for setting up a standalone git daemon

diff --git a/sha1_file.c b/sha1_file.c
index a7e3a2a9f963ce1bee1f54f05eaa8852b2bd2347..9fe2bd69a1edbaf1103de79d5e9d857939470d4f 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1354,11 +1354,19 @@ static void *unpack_compressed_entry(struct packed_git *p,
 
 #define MAX_DELTA_CACHE (256)
 
+static size_t delta_base_cached;
+
+static struct delta_base_cache_lru_list {
+       struct delta_base_cache_lru_list *prev;
+       struct delta_base_cache_lru_list *next;
+} delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
+
 static struct delta_base_cache_entry {
+       struct delta_base_cache_lru_list lru;
+       void *data;
        struct packed_git *p;
        off_t base_offset;
        unsigned long size;
-       void *data;
        enum object_type type;
 } delta_base_cache[MAX_DELTA_CACHE];
 
@@ -1368,11 +1376,11 @@ static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
 
        hash = (unsigned long)p + (unsigned long)base_offset;
        hash += (hash >> 8) + (hash >> 16);
-       return hash & 0xff;
+       return hash % MAX_DELTA_CACHE;
 }
 
 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
-       unsigned long *base_size, enum object_type *type)
+       unsigned long *base_size, enum object_type *type, int keep_cache)
 {
        void *ret;
        unsigned long hash = pack_entry_hash(p, base_offset);
@@ -1384,25 +1392,68 @@ static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
        return unpack_entry(p, base_offset, type, base_size);
 
 found_cache_entry:
-       ent->data = NULL;
+       if (!keep_cache) {
+               ent->data = NULL;
+               ent->lru.next->prev = ent->lru.prev;
+               ent->lru.prev->next = ent->lru.next;
+               delta_base_cached -= ent->size;
+       }
+       else {
+               ret = xmalloc(ent->size + 1);
+               memcpy(ret, ent->data, ent->size);
+               ((char *)ret)[ent->size] = 0;
+       }
        *type = ent->type;
        *base_size = ent->size;
        return ret;
 }
 
+static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
+{
+       if (ent->data) {
+               free(ent->data);
+               ent->data = NULL;
+               ent->lru.next->prev = ent->lru.prev;
+               ent->lru.prev->next = ent->lru.next;
+               delta_base_cached -= ent->size;
+       }
+}
+
 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
        void *base, unsigned long base_size, enum object_type type)
 {
        unsigned long hash = pack_entry_hash(p, base_offset);
        struct delta_base_cache_entry *ent = delta_base_cache + hash;
+       struct delta_base_cache_lru_list *lru;
+
+       release_delta_base_cache(ent);
+       delta_base_cached += base_size;
+
+       for (lru = delta_base_cache_lru.next;
+            delta_base_cached > delta_base_cache_limit
+            && lru != &delta_base_cache_lru;
+            lru = lru->next) {
+               struct delta_base_cache_entry *f = (void *)lru;
+               if (f->type == OBJ_BLOB)
+                       release_delta_base_cache(f);
+       }
+       for (lru = delta_base_cache_lru.next;
+            delta_base_cached > delta_base_cache_limit
+            && lru != &delta_base_cache_lru;
+            lru = lru->next) {
+               struct delta_base_cache_entry *f = (void *)lru;
+               release_delta_base_cache(f);
+       }
 
-       if (ent->data)
-               free(ent->data);
        ent->p = p;
        ent->base_offset = base_offset;
        ent->type = type;
        ent->data = base;
        ent->size = base_size;
+       ent->lru.next = &delta_base_cache_lru;
+       ent->lru.prev = delta_base_cache_lru.prev;
+       delta_base_cache_lru.prev->next = &ent->lru;
+       delta_base_cache_lru.prev = &ent->lru;
 }
 
 static void *unpack_delta_entry(struct packed_git *p,
@@ -1418,7 +1469,7 @@ static void *unpack_delta_entry(struct packed_git *p,
        off_t base_offset;
 
        base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
-       base = cache_or_unpack_entry(p, base_offset, &base_size, type);
+       base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
        if (!base)
                die("failed to read delta base object"
                    " at %"PRIuMAX" from %s",
@@ -1615,7 +1666,7 @@ static void *read_packed_sha1(const unsigned char *sha1,
        if (!find_pack_entry(sha1, &e, NULL))
                return NULL;
        else
-               return unpack_entry(e.p, e.offset, type, size);
+               return cache_or_unpack_entry(e.p, e.offset, size, type, 1);
 }
 
 /*