Author: stefan2
Date: Sat Apr 16 13:06:07 2011
New Revision: 1093983
URL: http://svn.apache.org/viewvc?rev=1093983&view=rev
Log:
In symmetry to svn_cache__get_partial, introduce a partial
setter / modifier API function that enabled the caller to
modify changed items without the full deserialization -
modification - serialization chain. Therefore, adding entries
to e.g. directories becomes O(1) instead of O(n).
+++ subversion/trunk/subversion/libsvn_subr/cache-membuffer.c Sat Apr 16
13:06:07 2011
@@ -1174,6 +1174,12 @@ membuffer_cache_get(svn_membuffer_t *cac
return deserializer(item, buffer, entry->size, pool);
}
+/* Look for the cache entry identified by KEY and KEY_LEN. FOUND indicates
+ * whether that entry exists. If not found, *ITEM will be NULL. Otherwise,
+ * the DESERIALIZER is called with that entry and the BATON provided
+ * and will extract the desired information. The result is set in *ITEM.
+ * Allocations will be done in POOL.
+ */
static svn_error_t *
membuffer_cache_get_partial(svn_membuffer_t *cache,
const void *key,
@@ -1239,6 +1245,105 @@ membuffer_cache_get_partial(svn_membuffe
return unlock_cache(cache, err);
}
+/* Look for the cache entry identified by KEY and KEY_LEN. If no entry
+ * has been found, the function returns without modifying the cache.
+ * Otherwise, FUNC is called with that entry and the BATON provided
+ * and may modify the cache entry. Allocations will be done in POOL.
+ */
+static svn_error_t *
+membuffer_cache_set_partial(svn_membuffer_t *cache,
+ const void *key,
+ apr_size_t key_len,
+ svn_cache__partial_setter_func_t func,
+ void *baton,
+ DEBUG_CACHE_MEMBUFFER_TAG_ARG
+ apr_pool_t *pool)
+{
+ apr_uint32_t group_index;
+ unsigned char to_find[KEY_SIZE];
+ entry_t *entry;
+ svn_error_t *err = SVN_NO_ERROR;
+
+ /* cache item lookup
+ */
+ group_index = get_group_index(&cache, key, key_len, to_find, pool);
+
+ SVN_ERR(lock_cache(cache));
+
+ entry = find_entry(cache, group_index, to_find, FALSE);
+ cache->total_reads++;
+
+ /* this function is a no-op if the item is not in cache
+ */
+ if (entry != NULL)
+ {
+ /* access the serialized cache item */
+ char *data = (char*)cache->data + entry->offset;
+ char *orig_data = data;
+ apr_size_t size = entry->size;
+
+ entry->hit_count++;
+ cache->hit_count++;
+ cache->total_writes++;
+
+#ifdef DEBUG_CACHE_MEMBUFFER
+
+ /* Check for overlapping entries.
+ */
+ SVN_ERR_ASSERT(entry->next == NO_INDEX ||
+ entry->offset + size
+<= get_entry(cache, entry->next)->offset);
+
+ /* Compare original content, type and key (hashes)
+ */
+ SVN_ERR(store_content_part(tag, data, size, pool));
+ SVN_ERR(assert_equal_tags(&entry->tag, tag));
+
+#endif
+
+ /* modify it, preferrably in-situ.
+ */
+ err = func(&data,&size, baton, pool);
+
+ /* if modification caused a re-allocation, we need to remove the old
+ * entry and to copy the new data back into cache.
+ */
+ if (data != orig_data)
