Merge branch 'master' into saravea

Conflicts:
	mod/blog/views/default/blog/sidebar/archives.php

1 files changed, 37 insertions, 38 deletions

diff --git a/engine/lib/database.php b/engine/lib/database.php
index 2b348366d..a7949788d 100644
--- a/engine/lib/database.php
+++ b/engine/lib/database.php
@@ -12,17 +12,19 @@
 /**
  * Query cache for all queries.
  *
- * Each query and its results are stored in this array as:
+ * Each query and its results are stored in this cache as:
  * <code>
- * $DB_QUERY_CACHE[$query] => array(result1, result2, ... resultN)
+ * $DB_QUERY_CACHE[query hash] => array(result1, result2, ... resultN)
  * </code>
+ * @see elgg_query_runner() for details on the hash.
  *
- * @warning be array this var may be an array or ElggStaticVariableCache depending on when called :(
+ * @warning Elgg used to set this as an empty array to turn off the cache
  *
- * @global ElggStaticVariableCache|array $DB_QUERY_CACHE
+ * @global ElggLRUCache|null $DB_QUERY_CACHE
+ * @access private
  */
 global $DB_QUERY_CACHE;
-$DB_QUERY_CACHE = array();
+$DB_QUERY_CACHE = null;
 
 /**
  * Queries to be executed upon shutdown.
@@ -40,6 +42,7 @@ $DB_QUERY_CACHE = array();
  * </code>
  *
  * @global array $DB_DELAYED_QUERIES
+ * @access private
  */
 global $DB_DELAYED_QUERIES;
 $DB_DELAYED_QUERIES = array();
@@ -51,6 +54,7 @@ $DB_DELAYED_QUERIES = array();
  * $dblink as $dblink[$name] => resource.  Use get_db_link($name) to retrieve it.
  *
  * @global resource[] $dblink
+ * @access private
  */
 global $dblink;
 $dblink = array();
@@ -61,6 +65,7 @@ $dblink = array();
  * Each call to the database increments this counter.
  *
  * @global integer $dbcalls
+ * @access private
  */
 global $dbcalls;
 $dbcalls = 0;
@@ -123,9 +128,8 @@ function establish_db_link($dblinkname = "readwrite") {
 
 	// Set up cache if global not initialized and query cache not turned off
 	if ((!$DB_QUERY_CACHE) && (!$db_cache_off)) {
-		// @todo everywhere else this is assigned to array(), making it dangerous to call
-		// object methods on this. We should consider making this an plain array
-		$DB_QUERY_CACHE = new ElggStaticVariableCache('db_query_cache');
+		// @todo if we keep this cache in 1.9, expose the size as a config parameter
+		$DB_QUERY_CACHE = new ElggLRUCache(200);
 	}
 }
 
@@ -395,16 +399,14 @@ function elgg_query_runner($query, $callback = null, $single = false) {
 
 	// Since we want to cache results of running the callback, we need to
 	// need to namespace the query with the callback and single result request.
-	// http://trac.elgg.org/ticket/4049
+	// https://github.com/elgg/elgg/issues/4049
 	$hash = (string)$callback . (int)$single . $query;
 
 	// Is cached?
 	if ($DB_QUERY_CACHE) {
-		$cached_query = $DB_QUERY_CACHE[$hash];
-
-		if ($cached_query !== FALSE) {
+		if (isset($DB_QUERY_CACHE[$hash])) {
 			elgg_log("DB query $query results returned from cache (hash: $hash)", 'NOTICE');
-			return $cached_query;
+			return $DB_QUERY_CACHE[$hash];
 		}
 	}
 
@@ -456,19 +458,12 @@ function elgg_query_runner($query, $callback = null, $single = false) {
  * @access private
  */
 function insert_data($query) {
-	global $DB_QUERY_CACHE;
 
 	elgg_log("DB query $query", 'NOTICE');
 	
 	$dblink = get_db_link('write');
 
-	// Invalidate query cache
-	if ($DB_QUERY_CACHE) {
-		/* @var ElggStaticVariableCache $DB_QUERY_CACHE */
-		$DB_QUERY_CACHE->clear();
-	}
-
-	elgg_log("Query cache invalidated", 'NOTICE');
+	_elgg_invalidate_query_cache();
 
 	if (execute_query("$query", $dblink)) {
 		return mysql_insert_id($dblink);
@@ -478,7 +473,7 @@ function insert_data($query) {
 }
 
 /**
- * Update a row in the database.
+ * Update the database.
  *
  * @note Altering the DB invalidates all queries in {@link $DB_QUERY_CACHE}.
  *
@@ -488,18 +483,12 @@ function insert_data($query) {
  * @access private
  */
 function update_data($query) {
-	global $DB_QUERY_CACHE;
 
 	elgg_log("DB query $query", 'NOTICE');
 
 	$dblink = get_db_link('write');
 
-	// Invalidate query cache
-	if ($DB_QUERY_CACHE) {
-		/* @var ElggStaticVariableCache $DB_QUERY_CACHE */
-		$DB_QUERY_CACHE->clear();
-		elgg_log("Query cache invalidated", 'NOTICE');
-	}
+	_elgg_invalidate_query_cache();
 
 	if (execute_query("$query", $dblink)) {
 		return TRUE;
@@ -509,7 +498,7 @@ function update_data($query) {
 }
 
 /**
- * Remove a row from the database.
+ * Remove data from the database.
  *
  * @note Altering the DB invalidates all queries in {@link $DB_QUERY_CACHE}.
  *
@@ -519,18 +508,12 @@ function update_data($query) {
  * @access private
  */
 function delete_data($query) {
-	global $DB_QUERY_CACHE;
 
 	elgg_log("DB query $query", 'NOTICE');
 
 	$dblink = get_db_link('write');
 
-	// Invalidate query cache
-	if ($DB_QUERY_CACHE) {
-		/* @var ElggStaticVariableCache $DB_QUERY_CACHE */
-		$DB_QUERY_CACHE->clear();
-		elgg_log("Query cache invalidated", 'NOTICE');
-	}
+	_elgg_invalidate_query_cache();
 
 	if (execute_query("$query", $dblink)) {
 		return mysql_affected_rows($dblink);
@@ -539,6 +522,22 @@ function delete_data($query) {
 	return FALSE;
 }
 
+/**
+ * Invalidate the query cache
+ *
+ * @access private
+ */
+function _elgg_invalidate_query_cache() {
+	global $DB_QUERY_CACHE;
+	if ($DB_QUERY_CACHE instanceof ElggLRUCache) {
+		$DB_QUERY_CACHE->clear();
+		elgg_log("Query cache invalidated", 'NOTICE');
+	} elseif ($DB_QUERY_CACHE) {
+		// In case someone sets the cache to an array and primes it with data
+		$DB_QUERY_CACHE = array();
+		elgg_log("Query cache invalidated", 'NOTICE');
+	}
+}
 
 /**
  * Return tables matching the database prefix {@link $CONFIG->dbprefix}% in the currently
@@ -669,7 +668,7 @@ function run_sql_script($scriptlocation) {
 
 /**
  * Format a query string for logging
- * 
+ *
  * @param string $query Query string
  * @return string
  * @access private