From 15b21c14a21cd3bafe144346d20f03e1c9512e4c Mon Sep 17 00:00:00 2001
From: David Rajchenbach-Teller <dteller@mozilla.com>
Date: Tue, 26 Feb 2013 12:08:28 -0500
Subject: [PATCH] Bug 840887 - DirectoryIterator.prototype.exists -
 asynchronous version. r=froydnj

---
 toolkit/components/osfile/osfile_async_front.jsm | 13 ++++++++++++-
 toolkit/components/osfile/osfile_async_worker.js |  6 ++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/toolkit/components/osfile/osfile_async_front.jsm b/toolkit/components/osfile/osfile_async_front.jsm
index 7329cc0caa88..40343af848ad 100644
--- a/toolkit/components/osfile/osfile_async_front.jsm
+++ b/toolkit/components/osfile/osfile_async_front.jsm
@@ -627,6 +627,18 @@ let DirectoryIterator = function DirectoryIterator(path, options) {
   this._isClosed = false;
 };
 DirectoryIterator.prototype = {
+  /**
+   * Determine whether the directory exists.
+   *
+   * @resolves {boolean}
+   */
+  exists: function exists() {
+    return this._itmsg.then(
+      function onSuccess(iterator) {
+        return Scheduler.post("DirectoryIterator_prototype_exists", [iterator]);
+      }
+    );
+  },
   /**
    * Get the next entry in the directory.
    *
@@ -728,7 +740,6 @@ DirectoryIterator.prototype = {
    */
   _next: function _next(iterator) {
     if (this._isClosed) {
-      LOG("DirectoryIterator._next", "closed");
       return this._itmsg;
     }
     let self = this;
diff --git a/toolkit/components/osfile/osfile_async_worker.js b/toolkit/components/osfile/osfile_async_worker.js
index 94128f986788..2c82a52020b5 100644
--- a/toolkit/components/osfile/osfile_async_worker.js
+++ b/toolkit/components/osfile/osfile_async_worker.js
@@ -356,6 +356,12 @@ if (this.Components) {
              this.close();
              OpenedDirectoryIterators.remove(dir);
            }, true);// ignore error to support double-closing |DirectoryIterator|
+       },
+       DirectoryIterator_prototype_exists: function exists(dir) {
+         return withDir(dir,
+           function do_exists() {
+             return this.exists();
+           });
        }
      };
   } catch(ex) {