1 /*
2  * cache-null.c: dummy caching object for Subversion
3  *
4  * ====================================================================
5  *    Licensed to the Apache Software Foundation (ASF) under one
6  *    or more contributor license agreements.  See the NOTICE file
7  *    distributed with this work for additional information
8  *    regarding copyright ownership.  The ASF licenses this file
9  *    to you under the Apache License, Version 2.0 (the
10  *    "License"); you may not use this file except in compliance
11  *    with the License.  You may obtain a copy of the License at
12  *
13  *      http://www.apache.org/licenses/LICENSE-2.0
14  *
15  *    Unless required by applicable law or agreed to in writing,
16  *    software distributed under the License is distributed on an
17  *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
18  *    KIND, either express or implied.  See the License for the
19  *    specific language governing permissions and limitations
20  *    under the License.
21  * ====================================================================
22  */
23 
24 #include "svn_private_config.h"
25 #include "cache.h"
26 
27 /* There is no dedicated cache data structure.  Instead, we store the
28  * cache ID directly in svn_cache__t.cache_internal .
29  */
30 
31 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)32 null_cache_get(void **value_p,
33                svn_boolean_t *found,
34                void *cache_void,
35                const void *key,
36                apr_pool_t *result_pool)
37 {
38   /* We know there is nothing to be found in this cache. */
39   *value_p = NULL;
40   *found = FALSE;
41 
42   return SVN_NO_ERROR;
43 }
44 
45 static svn_error_t *
null_cache_has_key(svn_boolean_t * found,void * cache_void,const void * key,apr_pool_t * scratch_pool)46 null_cache_has_key(svn_boolean_t *found,
47                    void *cache_void,
48                    const void *key,
49                    apr_pool_t *scratch_pool)
50 {
51   /* We know there is nothing to be found in this cache. */
52   *found = FALSE;
53   return SVN_NO_ERROR;
54 }
55 
56 static svn_error_t *
null_cache_set(void * cache_void,const void * key,void * value,apr_pool_t * scratch_pool)57 null_cache_set(void *cache_void,
58                const void *key,
59                void *value,
60                apr_pool_t *scratch_pool)
61 {
62   /* We won't cache anything. */
63   return SVN_NO_ERROR;
64 }
65 
66 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)67 null_cache_iter(svn_boolean_t *completed,
68                 void *cache_void,
69                 svn_iter_apr_hash_cb_t user_cb,
70                 void *user_baton,
71                 apr_pool_t *scratch_pool)
72 {
73   /* Iteration over an empty set is a no-op. */
74   if (completed)
75     *completed = TRUE;
76 
77   return SVN_NO_ERROR;
78 }
79 
80 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)81 null_cache_get_partial(void **value_p,
82                        svn_boolean_t *found,
83                        void *cache_void,
84                        const void *key,
85                        svn_cache__partial_getter_func_t func,
86                        void *baton,
87                        apr_pool_t *result_pool)
88 {
89   /* We know there is nothing to be found in this cache. */
90   *found = FALSE;
91   return SVN_NO_ERROR;
92 }
93 
94 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)95 null_cache_set_partial(void *cache_void,
96                        const void *key,
97                        svn_cache__partial_setter_func_t func,
98                        void *baton,
99                        apr_pool_t *scratch_pool)
100 {
101   /* We know there is nothing to update in this cache. */
102   return SVN_NO_ERROR;
103 }
104 
105 static svn_boolean_t
null_cache_is_cachable(void * cache_void,apr_size_t size)106 null_cache_is_cachable(void *cache_void,
107                        apr_size_t size)
108 {
109   /* We won't cache anything */
110   return FALSE;
111 }
112 
113 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)114 null_cache_get_info(void *cache_void,
115                     svn_cache__info_t *info,
116                     svn_boolean_t reset,
117                     apr_pool_t *result_pool)
118 {
119   const char *id = cache_void;
120 
121   info->id = apr_pstrdup(result_pool, id);
122 
123   info->used_entries = 0;
124   info->total_entries = 0;
125 
126   info->used_size = 0;
127   info->data_size = 0;
128   info->total_size = 0;
129 
130   return SVN_NO_ERROR;
131 }
132 
133 static svn_cache__vtable_t null_cache_vtable = {
134   null_cache_get,
135   null_cache_has_key,
136   null_cache_set,
137   null_cache_iter,
138   null_cache_is_cachable,
139   null_cache_get_partial,
140   null_cache_set_partial,
141   null_cache_get_info
142 };
143 
144 svn_error_t *
svn_cache__create_null(svn_cache__t ** cache_p,const char * id,apr_pool_t * result_pool)145 svn_cache__create_null(svn_cache__t **cache_p,
146                        const char *id,
147                        apr_pool_t *result_pool)
148 {
149   svn_cache__t *cache = apr_pcalloc(result_pool, sizeof(*cache));
150   cache->vtable = &null_cache_vtable;
151   cache->cache_internal = apr_pstrdup(result_pool, id);
152   cache->pretend_empty = FALSE; /* There is no point in pretending --
153                                    this cache _is_ empty. */
154 
155   *cache_p = cache;
156   return SVN_NO_ERROR;
157 }
158