Implement a class to chain multiple command preprocessors.

lib/Predis/Commands/Preprocessors/ICommandPreprocessorChain.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Predis\Commands\Preprocessors;
+
+interface ICommandPreprocessorChain
+    extends ICommandPreprocessor, \IteratorAggregate, \Countable {
+
+    public function add(ICommandPreprocessor $preprocessor);
+    public function remove(ICommandPreprocessor $preprocessor);
+    public function getPreprocessors();
+}

lib/Predis/Commands/Preprocessors/PreprocessorChain.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace Predis\Commands\Preprocessors;
+
+class PreprocessorChain implements ICommandPreprocessorChain, \ArrayAccess {
+    private $_preprocessors;
+
+    public function __construct($preprocessors = array()) {
+        foreach ($preprocessors as $preprocessor) {
+            $this->add($preprocessor);
+        }
+    }
+
+    public function add(ICommandPreprocessor $preprocessor) {
+        $this->_preprocessors[] = $preprocessor;
+    }
+
+    public function remove(ICommandPreprocessor $preprocessor) {
+        // TODO: find index of value
+    }
+
+    public function process(&$method, &$arguments) {
+        $count = count($this->_preprocessors);
+        for ($i = 0; $i < $count; $i++) {
+            $this->_preprocessors[$i]->process($method, $arguments);
+        }
+    }
+
+    public function getPreprocessors() {
+        return $this->_preprocessors;
+    }
+
+    public function getIterator() {
+        return new \ArrayIterator($this->_preprocessors);
+    }
+
+    public function count() {
+        return count($this->_preprocessors);
+    }
+
+    public function offsetExists($index) {
+        return isset($this->_preprocessors[$index]);
+    }
+
+    public function offsetGet($index) {
+        return $this->_preprocessors[$index];
+    }
+
+    public function offsetSet($index, $preprocessor) {
+        $this->_preprocessors[$index] = $preprocessor;
+    }
+
+    public function offsetUnset($index) {
+        unset($this->_preprocessors[$index]);
+    }
+}