Make cache type selectable based on config value

Provie a mechanism to specify cache type from NONE, APC, or MEMCACHE
based on a config variable.

If MEMCACHE type is selected, a list of servers can be specified to
provide multiserver support. Note that php-memcaced is required for
MEMCACHE support.

Lukas: Minor commenting style fixes.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>

3 files changed, 92 insertions, 46 deletions

diff --git a/web/lib/aur.inc.php b/web/lib/aur.inc.php
index 572d781a..4c2cc559 100644
--- a/web/lib/aur.inc.php
+++ b/web/lib/aur.inc.php
@@ -13,12 +13,7 @@ set_lang();
 include_once("config.inc.php");
 include_once("version.inc.php");
 include_once("acctfuncs.inc.php");
-
-# Check if APC extension is loaded, and set cache prefix if it is.
-if (!defined('EXTENSION_LOADED_APC')) {
-	define('EXTENSION_LOADED_APC', extension_loaded('apc'));
-	define('APC_PREFIX', 'aur:');
-}
+include_once("cachefuncs.inc.php");
 
 # see if the visitor is already logged in
 #
@@ -263,46 +258,6 @@ function db_query($query="", $db_handle="") {
 	return $result;
 }
 
-# Set a value in the cache (currently APC) if cache is available for use. If
-# not available, this becomes effectively a no-op (return value is
-# false). Accepts an optional TTL (defaults to 600 seconds).
-function set_cache_value($key, $value, $ttl=600) {
-	$status = false;
-	if (EXTENSION_LOADED_APC) {
-		$status = apc_store(APC_PREFIX.$key, $value, $ttl);
-	}
-	return $status;
-}
-
-# Get a value from the cache (currently APC) if cache is available for use. If
-# not available, this returns false (optionally sets passed in variable $status
-# to false, much like apc_fetch() behaves). This allows for testing the fetch
-# result appropriately even in the event that a 'false' value was the value in
-# the cache.
-function get_cache_value($key, &$status=false) {
-	if(EXTENSION_LOADED_APC) {
-		$ret = apc_fetch(APC_PREFIX.$key, $status);
-		if ($status) {
-			return $ret;
-		}
-	}
-	return $status;
-}
-
-# Run a simple db query, retrieving and/or caching the value if APC is
-# available for use. Accepts an optional TTL value (defaults to 600 seconds).
-function db_cache_value($dbq, $dbh, $key, $ttl=600) {
-	$status = false;
-	$value = get_cache_value($key, $status);
-	if (!$status) {
-		$result = db_query($dbq, $dbh);
-		$row = mysql_fetch_row($result);
-		$value = $row[0];
-		set_cache_value($key, $value, $ttl);
-	}
-	return $value;
-}
-
 # set up the visitor's language
 #
 function set_lang() {
diff --git a/web/lib/cachefuncs.inc.php b/web/lib/cachefuncs.inc.php
new file mode 100644
index 00000000..3485b013
--- /dev/null
+++ b/web/lib/cachefuncs.inc.php
@@ -0,0 +1,82 @@
+<?php
+
+if (!defined('CACHE_TYPE')) {
+	define('CACHE_TYPE', 'NONE');
+}
+
+# Check if APC extension is loaded, and set cache prefix if it is.
+if (CACHE_TYPE == 'APC' && !defined('EXTENSION_LOADED_APC')) {
+	define('EXTENSION_LOADED_APC', extension_loaded('apc'));
+	define('CACHE_PREFIX', 'aur:');
+}
+
+# Check if memcache extension is loaded, and set cache prefix if it is.
+if (CACHE_TYPE == 'MEMCACHE' && !defined('EXTENSION_LOADED_MEMCACHE')) {
+	define('EXTENSION_LOADED_MEMCACHE', extension_loaded('memcached'));
+	define('CACHE_PREFIX', 'aur:');
+	global $memcache;
+	$memcache = new Memcached();
+	$mcs = defined('MEMCACHE_SERVERS') ? MEMCACHE_SERVERS : '127.0.0.1:11211';
+	foreach (explode(',', $mcs) as $elem) {
+		$telem = trim($elem);
+		$mcserver = explode(':', $telem);
+		$memcache->addServer($mcserver[0], intval($mcserver[1]));
+	}
+}
+
+# Set a value in the cache (currently APC) if cache is available for use. If
+# not available, this becomes effectively a no-op (return value is
+# false). Accepts an optional TTL (defaults to 600 seconds).
+function set_cache_value($key, $value, $ttl=600) {
+	$status = false;
+	if (defined('EXTENSION_LOADED_APC')) {
+		$status = apc_store(CACHE_PREFIX.$key, $value, $ttl);
+	}
+	if (defined('EXTENSION_LOADED_MEMCACHE')) {
+		global $memcache;
+		$status = $memcache->set(CACHE_PREFIX.$key, $value, $ttl);
+	}
+	return $status;
+}
+
+# Get a value from the cache (currently APC) if cache is available for use. If
+# not available, this returns false (optionally sets passed in variable $status
+# to false, much like apc_fetch() behaves). This allows for testing the fetch
+# result appropriately even in the event that a 'false' value was the value in
+# the cache.
+function get_cache_value($key, &$status=false) {
+	if(defined('EXTENSION_LOADED_APC')) {
+		$ret = apc_fetch(CACHE_PREFIX.$key, $status);
+		if ($status) {
+			return $ret;
+		}
+	}
+	if (defined('EXTENSION_LOADED_MEMCACHE')) {
+		global $memcache;
+		$ret = $memcache->get(CACHE_PREFIX.$key);
+		if (!$ret) {
+			$status = false;
+		}
+		else {
+			$status = true;
+		}
+		return $ret;
+	}
+	return $status;
+}
+
+# Run a simple db query, retrieving and/or caching the value if APC is
+# available for use. Accepts an optional TTL value (defaults to 600 seconds).
+function db_cache_value($dbq, $dbh, $key, $ttl=600) {
+	$status = false;
+	$value = get_cache_value($key, $status);
+	if (!$status) {
+		$result = db_query($dbq, $dbh);
+		$row = mysql_fetch_row($result);
+		$value = $row[0];
+		set_cache_value($key, $value, $ttl);
+	}
+	return $value;
+}
+
+?>
diff --git a/web/lib/config.inc.php.proto b/web/lib/config.inc.php.proto
index 43c64d22..f710844d 100644
--- a/web/lib/config.inc.php.proto
+++ b/web/lib/config.inc.php.proto
@@ -24,6 +24,15 @@ define("DEFAULT_LANG", "en");
 # development. Should not be enabled in production. Default to 0 (off).
 define("SQL_DEBUG", 0);
 
+# Set cache type. Either "APC", "MEMCACHE", or "NONE". Defaults to NONE.
+#define("CACHE_TYPE", "APC");
+#define("CACHE_TYPE", "MEMCACHE");
+
+# If using memcache cache_type, list servers. You can separate multiple servers
+# with a comma, ex: '127.0.0.1:11211,127.0.0.1:11212'. If undefined, defaults
+# to '127.0.0.1:11211'.
+#define("MEMCACHE_SERVERS", '127.0.0.1:11211');
+
 # Languages we have translations for
 $SUPPORTED_LANGS = array(
 	"ca" => "Català",