[Form] Added getParent() to PropertyPath

src/Symfony/Component/Form/Util/PropertyPath.php

@@ -27,26 +27,32 @@ class PropertyPath implements \IteratorAggregate
      * The elements of the property path
      * @var array
      */
-    protected $elements = array();
+    private $elements = array();
 
     /**
      * The number of elements in the property path
      * @var integer
      */
-    protected $length;
+    private $length;
 
     /**
      * Contains a Boolean for each property in $elements denoting whether this
      * element is an index. It is a property otherwise.
      * @var array
      */
-    protected $isIndex = array();
+    private $isIndex = array();
 
     /**
      * String representation of the path
      * @var string
      */
-    protected $string;
+    private $string;
+
+    /**
+     * Positions where the individual elements start in the string representation
+     * @var array
+     */
+    private $positions;
 
     /**
      * Parses the given property path
@@ -67,6 +73,8 @@ class PropertyPath implements \IteratorAggregate
         $pattern = '/^(([^\.\[]+)|\[([^\]]+)\])(.*)/';
 
         while (preg_match($pattern, $remaining, $matches)) {
+            $this->positions[] = $position;
+
             if ('' !== $matches[2]) {
                 $this->elements[] = $matches[2];
                 $this->isIndex[] = false;
@@ -102,6 +110,33 @@ class PropertyPath implements \IteratorAggregate
         return $this->string;
     }
 
+    /**
+     * Returns the parent property path.
+     *
+     * The parent property path is the one that contains the same items as
+     * this one except for the last one.
+     *
+     * If this property path only contains one item, null is returned.
+     *
+     * @return PropertyPath The parent path or null.
+     */
+    public function getParent()
+    {
+        if ($this->length <= 1) {
+            return null;
+        }
+
+        $parent = clone $this;
+
+        --$parent->length;
+        $parent->string = substr($parent->string, 0, $parent->positions[$parent->length]);
+        array_pop($parent->elements);
+        array_pop($parent->isIndex);
+        array_pop($parent->positions);
+
+        return $parent;
+    }
+
     /**
      * Returns a new iterator for this path
      *

tests/Symfony/Tests/Component/Form/PropertyPathTest.php

@@ -391,4 +391,25 @@ class PropertyPathTest extends \PHPUnit_Framework_TestCase
 
         new PropertyPath(null);
     }
+
+    public function testGetParent_dot()
+    {
+        $propertyPath = new PropertyPath('grandpa.parent.child');
+
+        $this->assertEquals(new PropertyPath('grandpa.parent'), $propertyPath->getParent());
+    }
+
+    public function testGetParent_index()
+    {
+        $propertyPath = new PropertyPath('grandpa.parent[child]');
+
+        $this->assertEquals(new PropertyPath('grandpa.parent'), $propertyPath->getParent());
+    }
+
+    public function testGetParent_noParent()
+    {
+        $propertyPath = new PropertyPath('path');
+
+        $this->assertNull($propertyPath->getParent());
+    }
 }