Implement If validator.

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1609 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/ConfigSchema/Validator/If.php

@@ -0,0 +1,49 @@
+<?php
+
+/**
+ * If a validator passes, run another validator.
+ */
+class HTMLPurifier_ConfigSchema_Validator_If extends HTMLPurifier_ConfigSchema_Validator
+{
+    
+    protected $condition;
+    protected $then;
+    protected $else;
+    
+    public function __construct($cond = null) {
+        $this->setCondition($cond);
+    }
+    
+    /**
+     * @param $validator Validator to run as a condition. Exceptions thrown by it
+     *        do not bubble up.
+     */
+    public function setCondition($validator) {
+        $this->condition = $validator;
+    }
+    
+    /**
+     * @param $validator Validator to run if condition is true
+     */
+    public function setThen($validator) {
+        $this->then = $validator;
+    }
+    
+    /**
+     * @param $validator Validator to run if condition is false
+     */
+    public function setElse($validator) {
+        $this->else = $validator;
+    }
+    
+    public function validate(&$arr, $interchange) {
+        try {
+            $this->condition->validate($arr, $interchange);
+        } catch (HTMLPurifier_ConfigSchema_Exception $e) {
+            if ($this->else) $this->else->validate($arr, $interchange);
+            return;
+        }
+        if ($this->then) $this->then->validate($arr, $interchange);
+    }
+    
+}