X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/763d5e6ad88ef3ba1cd1d7742d060e4f1e54c6b8..refs/heads/master:/lib/cache.c

diff --git a/lib/cache.c b/lib/cache.c
index 1379f66..52629de 100644
--- a/lib/cache.c
+++ b/lib/cache.c
@@ -1,45 +1,57 @@
 /*
  * This file is part of DisOrder
- * Copyright (C) 2006 Richard Kettlewell
+ * Copyright (C) 2006-2008 Richard Kettlewell
  *
- * This program is free software; you can redistribute it and/or modify
+ * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
- * USA
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+/** @file lib/cache.c @brief Object caching */
 
-#include <config.h>
-#include "types.h"
+#include "common.h"
 
 #include <time.h>
 
 #include "hash.h"
 #include "mem.h"
 #include "log.h"
+#include "syscalls.h"
 #include "cache.h"
 
+/** @brief The global cache */
 static hash *h;
 
+/** @brief One cache entry */
 struct cache_entry {
+  /** @brief What type of object this is */
   const struct cache_type *type;
+
+  /** @brief Pointer to object value */
   const void *value;
+
+  /** @brief Time that object was inserted into cache */
   time_t birth;
 };
 
+/** @brief Return true if object @p c has expired */
 static int expired(const struct cache_entry *c, time_t now) {
   return now - c->birth > c->type->lifetime;
 }
 
+/** @brief Insert an object into the cache
+ * @param type Pointer to object type
+ * @param key Unique key
+ * @param value Pointer to value
+ */
 void cache_put(const struct cache_type *type,
                const char *key, const void *value) {
   struct cache_entry *c;
@@ -49,22 +61,28 @@ void cache_put(const struct cache_type *type,
   c = xmalloc(sizeof *c);
   c->type = type;
   c->value = value;
-  time(&c->birth);
+  xtime(&c->birth);
   hash_add(h, key, c,  HASH_INSERT_OR_REPLACE);
 }
 
+/** @brief Look up an object in the cache
+ * @param type Pointer to object type
+ * @param key Unique key
+ * @return Pointer to object value or NULL if not found
+ */
 const void *cache_get(const struct cache_type *type, const char *key) {
   const struct cache_entry *c;
   
   if(h
      && (c = hash_find(h, key))
      && c->type == type
-     && !expired(c, time(0)))
+     && !expired(c, xtime(0)))
     return c->value;
   else
     return 0;
 }
 
+/** @brief Call used by from cache_expire() */
 static int expiry_callback(const char *key, void *value, void *u) {
   const struct cache_entry *c = value;
   const time_t *now = u;
@@ -74,15 +92,19 @@ static int expiry_callback(const char *key, void *value, void *u) {
   return 0;
 }
 
+/** @brief Expire the cache
+ *
+ * Called from time to time to expire cache entries. */
 void cache_expire(void) {
   time_t now;
 
   if(h) {
-    time(&now);
+    xtime(&now);
     hash_foreach(h, expiry_callback, &now);
   }
 }
 
+/** @brief Callback used by cache_clean() */
 static int clean_callback(const char *key, void *value, void *u) {
   const struct cache_entry *c = value;
   const struct cache_type *type = u;
@@ -92,11 +114,24 @@ static int clean_callback(const char *key, void *value, void *u) {
   return 0;
 }
 
+/** @brief Clean the cache
+ * @param type Pointer to type to clean
+ *
+ * Removes all entries of type @p type from the cache.
+ */
 void cache_clean(const struct cache_type *type) {
   if(h)
     hash_foreach(h, clean_callback, (void *)type);
 }
 
+/** @brief Report cache size
+ *
+ * Returns the number of objects in the cache
+ */
+size_t cache_count(void) {
+  return h ? hash_count(h) : 0;
+}
+
 /*
 Local Variables:
 c-basic-offset:2