MDL-36362 cache: added simpledata definition option

cache/README.md

@@ -9,6 +9,7 @@ A definition:
      $definitions = array(
         'string' => array(                            // Required, unique to the component
             'mode' => cache_store::MODE_APPLICATION,  // Required
+            'simpledata' => false,                    // Optional
             'requireidentifiers' => array(            // Optional
                 'lang'
             ),
@@ -104,6 +105,7 @@ The following settings are required for a definition:
 * mode - Application, session or request.
 
 The following optional settings can also be defined:
+* simpledata - Set to true if you know that you will only be storing scalar values or arrays of scalar values. Avoids costly investigation of data types.
 * requireidentifiers - Any identifiers the definition requires. Must be provided when creating the loader.
 * requiredataguarantee - If set to true then only stores that support data guarantee will be used.
 * requiremultipleidentifiers - If set to true then only stores that support multiple identifiers will be used.

cache/classes/definition.php

@@ -39,6 +39,8 @@ defined('MOODLE_INTERNAL') || die();
  *          [int] Sets the mode for the definition. Must be one of cache_store::MODE_*
  *
  * Optional settings:
+ *     + simpledata
+ *          [bool] If set to true we know that the data is scalar or array of scalar.
  *     + requireidentifiers
  *          [array] An array of identifiers that must be provided to the cache when it is created.
  *     + requiredataguarantee
@@ -127,6 +129,12 @@ class cache_definition {
      */
     protected $area;
 
+    /**
+     * Set to true if we know the data is scalar or array of scalar.
+     * @var bool
+     */
+    protected $simpledata = false;
+
     /**
      * An array of identifiers that must be provided when the definition is used to create a cache.
      * @var array
@@ -281,6 +289,7 @@ class cache_definition {
         $area = (string)$definition['area'];
 
         // Set the defaults.
+        $simpledata = false;
         $requireidentifiers = array();
         $requiredataguarantee = false;
         $requiremultipleidentifiers = false;
@@ -297,6 +306,9 @@ class cache_definition {
         $mappingsonly = false;
         $invalidationevents = array();
 
+        if (array_key_exists('simpledata', $definition)) {
+            $simpledata = (bool)$definition['simpledata'];
+        }
         if (array_key_exists('requireidentifiers', $definition)) {
             $requireidentifiers = (array)$definition['requireidentifiers'];
         }
@@ -398,6 +410,7 @@ class cache_definition {
         $cachedefinition->mode = $mode;
         $cachedefinition->component = $component;
         $cachedefinition->area = $area;
+        $cachedefinition->simpledata = $simpledata;
         $cachedefinition->requireidentifiers = $requireidentifiers;
         $cachedefinition->requiredataguarantee = $requiredataguarantee;
         $cachedefinition->requiremultipleidentifiers = $requiremultipleidentifiers;
@@ -534,6 +547,14 @@ class cache_definition {
         return $this->mappingsonly;
     }
 
+    /**
+     * Returns true if the data is known to be scalar or array of scalar.
+     * @return bool
+     */
+    public function uses_simple_data() {
+        return $this->simpledata;
+    }
+
     /**
      * Returns true if this definition requires a data guarantee from the cache stores being used.
      * @return bool

cache/classes/loaders.php

@@ -498,6 +498,9 @@ class cache implements cache_loader {
      * @param stdClass|array $data
      */
     protected function unref($data) {
+        if ($this->definition->uses_simple_data()) {
+            return $data;
+        }
         // Check if it requires serialisation in order to produce a reference free copy.
         if ($this->requires_serialisation($data)) {
             // Damn, its going to have to be serialise.

lib/db/caches.php

@@ -31,6 +31,7 @@ $definitions = array(
     // Used to store processed lang files.
     'string' => array(
         'mode' => cache_store::MODE_APPLICATION,
+        'simpledata' => true,
         'persistent' => true,
         'persistentmaxsize' => 3
     ),
@@ -48,14 +49,16 @@ $definitions = array(
     // Used to store data from the config + config_plugins table in the database.
     'config' => array(
         'mode' => cache_store::MODE_APPLICATION,
-        'persistent' => true
+        'persistent' => true,
+        'simpledata' => true
     ),
 
     // Event invalidation cache.
     'eventinvalidation' => array(
         'mode' => cache_store::MODE_APPLICATION,
         'persistent' => true,
-        'requiredataguarantee' => true
+        'requiredataguarantee' => true,
+        'simpledata' => true,
     ),
 
     // Cache for question definitions. This is used by the question_bank class.

version.php

@@ -30,7 +30,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 
-$version  = 2012110101.00;              // YYYYMMDD      = weekly release date of this DEV branch
+$version  = 2012110102.00;              // YYYYMMDD      = weekly release date of this DEV branch
                                         //         RR    = release increments - 00 in DEV branches
                                         //           .XX = incremental changes