Feature/set mode

src/Stash/Interfaces/ItemInterface.php

@@ -32,6 +32,13 @@ public function setPool(PoolInterface $driver);
      */
     public function setKey($key, $namespace = null);
 
+    /**
+     * Sets the pool mode
+     *
+     * @param $mode
+     */
+    public function setMode($mode);
+
     /**
      * This disables any IO operations by this object, effectively preventing
      * the reading and writing of new data.

src/Stash/Interfaces/PoolInterface.php

@@ -24,12 +24,27 @@ interface PoolInterface
      *
      * Using this function developers can have the pool class generate custom Item objects.
      *
-     * @param  string                    $class
+     * @param string $class
      * @return bool
-     * @throws \InvalidArgumentException When passed invalid or nonexistant classes.
+     * @throws \InvalidArgumentException When passed invalid or nonexistent classes.
      */
     public function setItemClass($class);
 
+    /**
+     * Changes the mode of the pool
+     *
+     * Using this function developers can determine how Stash handles the cache
+     * @param $mode
+     * @return bool
+     */
+    public function setMode($mode);
+
+    /**
+     * Returns the mode of the pool
+     * @return int
+     */
+    public function getMode();
+
     /**
      * Returns an initialized Item for a given Key.
      *

src/Stash/Item.php

@@ -51,6 +51,13 @@ class Item implements ItemInterface
      */
     const SP_PRECOMPUTE   = 4;
 
+    /**
+     * The pool's mode
+     *
+     * @var int
+     */
+    private $mode;
+
     /**
      * This is the default time, in seconds, that objects are cached for.
      *
@@ -211,7 +218,11 @@ private function executeClear()
     public function get($invalidation = 0, $arg = null, $arg2 = null)
     {
         try {
-            return $this->executeGet($invalidation, $arg, $arg2);
+            if ($this->mode == Mode::WRITE_ONLY) {
+                return null;
+            } else {
+                return $this->executeGet($invalidation, $arg, $arg2);
+            }
         } catch (Exception $e) {
             $this->logException('Retrieving from cache caused exception.', $e);
             $this->disable();
@@ -262,6 +273,10 @@ private function executeGet($invalidation, $arg, $arg2)
      */
     public function isMiss()
     {
+        if ($this->mode == Mode::FORCE_MISS) {
+            return true;
+        }
+
         if (!isset($this->isHit)) {
             $this->get();
         }
@@ -303,7 +318,11 @@ public function lock($ttl = null)
     public function set($data, $ttl = null)
     {
         try {
-            return $this->executeSet($data, $ttl);
+            if ($this->mode == Mode::READ_ONLY) {
+                return false;
+            } else {
+                return $this->executeSet($data, $ttl);
+            }
         } catch (Exception $e) {
             $this->logException('Setting value in cache caused exception.', $e);
             $this->disable();
@@ -373,6 +392,7 @@ public function isDisabled()
     {
         return self::$runtimeDisable
                 || !$this->cacheEnabled
+                || $this->mode == Mode::DISABLED
                 || (defined('STASH_DISABLE_CACHE') && STASH_DISABLE_CACHE);
     }
 
@@ -616,4 +636,12 @@ protected function setupKey($key)
         array_unshift($key, 'cache');
         $this->key = array_map('strtolower', $key);
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setMode($mode)
+    {
+        $this->mode = $mode;
+    }
 }

src/Stash/Mode.php

@@ -0,0 +1,43 @@
+<?php namespace Stash;
+
+class Mode
+{
+    /**
+     * Normal Mode
+     *
+     * Default value
+     */
+    const NORMAL = 0;
+
+    /**
+     * Read only mode
+     *
+     * Set() has no effect
+     */
+    const READ_ONLY = 1;
+
+    /**
+     * Write only mode
+     *
+     * Get() has no effect
+     */
+    const WRITE_ONLY = 2;
+
+    /**
+     * Disabled mode
+     *
+     * Get() and Set() has no effect.
+     *
+     * Get() will return null
+     */
+    const DISABLED = 3;
+
+    /**
+     * Forced miss mode
+     *
+     * Get() and Set() work normally.
+     *
+     * isMiss() will always return true
+     */
+    const FORCE_MISS = 4;
+}

src/Stash/Pool.php

@@ -46,6 +46,14 @@ class Pool implements PoolInterface
      */
     protected $itemClass = '\Stash\Item';
 
+
+    /**
+     * Default "mode" for the pool to use.
+     *
+     * @var int
+     */
+    protected $mode = Mode::NORMAL;
+
     /**
      * If set various then errors and exceptions will get passed to the PSR Compliant logging library. This
      * can be set using the setLogger() function in this class.
@@ -67,14 +75,19 @@ class Pool implements PoolInterface
      * default.
      *
      * @param DriverInterface $driver
+     * @param Mode $mode
      */
-    public function __construct(DriverInterface $driver = null)
+    public function __construct(DriverInterface $driver = null, $mode = null)
     {
         if (isset($driver)) {
             $this->setDriver($driver);
         } else {
             $this->driver = new Ephemeral();
         }
+
+        if (isset($mode)) {
+            $this->setMode($mode);
+        }
     }
 
     /**
@@ -138,6 +151,7 @@ public function getItem()
         $item = new $this->itemClass();
         $item->setPool($this);
         $item->setKey($key, $namespace);
+        $item->setMode($this->mode);
 
         if ($this->isDisabled) {
             $item->disable();
@@ -290,4 +304,22 @@ protected function logException($message, $exception)
 
         return true;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setMode($mode)
+    {
+        $this->mode = $mode;
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getMode()
+    {
+        return $this->mode;
+    }
 }

tests/Stash/Test/AbstractPoolTest.php

@@ -11,6 +11,7 @@
 
 namespace Stash\Test;
 
+use Stash\Mode;
 use Stash\Pool;
 use Stash\Driver\Ephemeral;
 use Stash\Test\Stubs\LoggerStub;
@@ -68,6 +69,21 @@ public function testGetItem()
         $this->assertAttributeEquals('TestNamespace', 'namespace', $item, 'Pool sets Item namespace.');
     }
 
+    public function testModeGetterSetters()
+    {
+        $pool = $this->getTestPool();
+
+        $mode_set = Mode::DISABLED;
+
+        $mode = $pool->setMode($mode_set);
+
+        $this->assertTrue($mode, 'Mode should return true upon being set.');
+
+        $mode_returned = $pool->getMode();
+
+        $this->assertTrue($mode_set === $mode_returned, 'The returned mode is not the same as the set mode');
+    }
+
     /**
      * @expectedException InvalidArgumentException
      * @expectedExceptionMessage Item constructor requires a key.

tests/Stash/Test/Stubs/PoolGetDriverStub.php

@@ -72,4 +72,14 @@ public function setLogger($logger)
     {
         return false;
     }
+
+    public function setMode($mode)
+    {
+        return false;
+    }
+
+    public function getMode()
+    {
+        return false;
+    }
 }