1 files changed, 157 insertions, 0 deletions
diff --git a/subversion/libsvn_subr/cache-null.c b/subversion/libsvn_subr/cache-null.c
new file mode 100644
index 0000000000000..3b7ee12d0a1db
--- /dev/null
+++ b/subversion/libsvn_subr/cache-null.c
@@ -0,0 +1,157 @@
+/*
+ * cache-null.c: dummy caching object for Subversion
+ *
+ * ====================================================================
+ *    Licensed to the Apache Software Foundation (ASF) under one
+ *    or more contributor license agreements.  See the NOTICE file
+ *    distributed with this work for additional information
+ *    regarding copyright ownership.  The ASF licenses this file
+ *    to you under the Apache License, Version 2.0 (the
+ *    "License"); you may not use this file except in compliance
+ *    with the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing,
+ *    software distributed under the License is distributed on an
+ *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *    KIND, either express or implied.  See the License for the
+ *    specific language governing permissions and limitations
+ *    under the License.
+ * ====================================================================
+ */
+
+#include "svn_private_config.h"
+#include "cache.h"
+
+/* There is no dedicated cache data structure.  Instead, we store the
+ * cache ID directly in svn_cache__t.cache_internal .
+ */
+
+static svn_error_t *
+null_cache_get(void **value_p,
+               svn_boolean_t *found,
+               void *cache_void,
+               const void *key,
+               apr_pool_t *result_pool)
+{
+  /* We know there is nothing to be found in this cache. */
+  *value_p = NULL;
+  *found = FALSE;
+
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+null_cache_has_key(svn_boolean_t *found,
+                   void *cache_void,
+                   const void *key,
+                   apr_pool_t *scratch_pool)
+{
+  /* We know there is nothing to be found in this cache. */
+  *found = FALSE;
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+null_cache_set(void *cache_void,
+               const void *key,
+               void *value,
+               apr_pool_t *scratch_pool)
+{
+  /* We won't cache anything. */
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+null_cache_iter(svn_boolean_t *completed,
+                void *cache_void,
+                svn_iter_apr_hash_cb_t user_cb,
+                void *user_baton,
+                apr_pool_t *scratch_pool)
+{
+  /* Iteration over an empty set is a no-op. */
+  if (completed)
+    *completed = TRUE;
+
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+null_cache_get_partial(void **value_p,
+                       svn_boolean_t *found,
+                       void *cache_void,
+                       const void *key,
+                       svn_cache__partial_getter_func_t func,
+                       void *baton,
+                       apr_pool_t *result_pool)
+{
+  /* We know there is nothing to be found in this cache. */
+  *found = FALSE;
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+null_cache_set_partial(void *cache_void,
+                       const void *key,
+                       svn_cache__partial_setter_func_t func,
+                       void *baton,
+                       apr_pool_t *scratch_pool)
+{
+  /* We know there is nothing to update in this cache. */
+  return SVN_NO_ERROR;
+}
+
+static svn_boolean_t
+null_cache_is_cachable(void *cache_void,
+                       apr_size_t size)
+{
+  /* We won't cache anything */
+  return FALSE;
+}
+
+static svn_error_t *
+null_cache_get_info(void *cache_void,
+                    svn_cache__info_t *info,
+                    svn_boolean_t reset,
+                    apr_pool_t *result_pool)
+{
+  const char *id = cache_void;
+
+  info->id = apr_pstrdup(result_pool, id);
+
+  info->used_entries = 0;
+  info->total_entries = 0;
+
+  info->used_size = 0;
+  info->data_size = 0;
+  info->total_size = 0;
+
+  return SVN_NO_ERROR;
+}
+
+static svn_cache__vtable_t null_cache_vtable = {
+  null_cache_get,
+  null_cache_has_key,
+  null_cache_set,
+  null_cache_iter,
+  null_cache_is_cachable,
+  null_cache_get_partial,
+  null_cache_set_partial,
+  null_cache_get_info
+};
+
+svn_error_t *
+svn_cache__create_null(svn_cache__t **cache_p,
+                       const char *id,
+                       apr_pool_t *result_pool)
+{
+  svn_cache__t *cache = apr_pcalloc(result_pool, sizeof(*cache));
+  cache->vtable = &null_cache_vtable;
+  cache->cache_internal = apr_pstrdup(result_pool, id);
+  cache->pretend_empty = FALSE; /* There is no point in pretending --
+                                   this cache _is_ empty. */
+
+  *cache_p = cache;
+  return SVN_NO_ERROR;
+}