implement RecursiveArrayIterator

I went through all the tests that mentioned this and looked at them. All of them don't pass because of other missing SPL problems not related to this class (and this class is simple so I wouldn't assume them to blame to it).

Closes #766

hphp/NEWS

@@ -1,5 +1,6 @@
 
 "Tamale" 7/22/2013
+  - Implement RecursiveArrayIterator
   - Optimize vector-shaped Arrays (arrays with keys in range 0..size-1)
   - Enable HHBC by default in debug builds
   - Implement SplObjectStorage::getInfo()

hphp/system/php.txt

@@ -36,6 +36,9 @@ hphp/system/php/spl/iterators/IteratorIterator.php
 hphp/system/php/spl/iterators/FilterIterator.php
 hphp/system/php/spl/iterators/RecursiveFilterIterator.php
 
+hphp/system/php/spl/iterators/ArrayIterator.php
+hphp/system/php/spl/iterators/RecursiveArrayIterator.php
+
 hphp/system/php/filter/filter_has_var.php
 hphp/system/php/filter/filter_input.php
 hphp/system/php/filter/filter_var_array.php
@@ -67,7 +70,6 @@ hphp/system/php/spl/datastructures/SplFixedArray.php
 hphp/system/php/spl/datastructures/SplObjectStorage.php
 hphp/system/php/spl/datastructures/SplPriorityQueue.php
 hphp/system/php/spl/iterators/AppendIterator.php
-hphp/system/php/spl/iterators/ArrayIterator.php
 hphp/system/php/spl/iterators/EmptyIterator.php
 hphp/system/php/spl/iterators/InfiniteIterator.php
 hphp/system/php/spl/iterators/LimitIterator.php

hphp/system/php/spl/iterators/RecursiveArrayIterator.php

@@ -0,0 +1,54 @@
+<?php
+
+// This doc comment block generated by idl/sysdoc.php
+/**
+ * ( excerpt from http://php.net/manual/en/class.recursivearrayiterator.php
+ * )
+ *
+ * This iterator allows to unset and modify values and keys while
+ * iterating over Arrays and Objects in the same way as the ArrayIterator.
+ * Additionally it is possible to iterate over the current iterator entry.
+ *
+ */
+class RecursiveArrayIterator
+  extends ArrayIterator
+  implements RecursiveIterator {
+
+  const CHILD_ARRAYS_ONLY = 4;
+
+  // This doc comment block generated by idl/sysdoc.php
+  /**
+   * ( excerpt from
+   * http://php.net/manual/en/recursivearrayiterator.getchildren.php )
+   *
+   * Returns an iterator for the current iterator entry.
+   *
+   * @return     mixed   An iterator for the current entry, if it is an array
+   *                     or object.
+   */
+  public function getChildren() {
+    return new RecursiveArrayIterator(
+      $this->hasChildren() ? $this->current() : null,
+      $this->getFlags()
+    );
+  }
+
+  // This doc comment block generated by idl/sysdoc.php
+  /**
+   * ( excerpt from
+   * http://php.net/manual/en/recursivearrayiterator.haschildren.php )
+   *
+   * Returns whether current entry is an array or an object for which an
+   * iterator can be obtained via RecursiveArrayIterator::getChildren().
+   *
+   * @return     mixed   Returns TRUE if the current entry is an array or an
+   *                     object, otherwise FALSE is returned.
+   */
+  public function hasChildren() {
+    return
+      is_array($this->current()) ||
+      (is_object($this->current()) &&
+       ($this->getFlags() & self::CHILD_ARRAYS_ONLY) == 0);
+  }
+
+}

hphp/system/php/spl/iterators/RecursiveIteratorIterator.php

@@ -66,9 +66,9 @@ public function __construct($iterator,
    */
   public function getInnerIterator() {
     $it = $this->iterators[count($this->iterators)-1][0];
-    if (!$it instanceof RecursiveDirectoryIterator) {
+    if (!$it instanceof RecursiveIterator) {
       throw new Exception(
-        "RecursiveIteratorIterator only supports RecursiveDirectoryIterator"
+        "inner iterator must implement RecursiveIterator"
       );
     }
     return $it;
@@ -200,7 +200,7 @@ public function valid() {
 
     $it = $this->getInnerIterator();
     if ($it->valid() &&
-        $it->isDir() &&
+        $it->hasChildren() &&
         ($this->mode == self::LEAVES_ONLY ||
          ($this->mode == self::CHILD_FIRST &&
           $this->getInnerIteratorFlag() == 0))) {