Bug 808492 - Support double-closing DirectoryIterator in asynchronous mode. r=dteller

toolkit/components/osfile/osfile_async_worker.js

@@ -145,6 +145,7 @@ if (this.Components) {
       *
       * @param {*} id A unique identifier, as used by |OpenFiles|.
       * @param {Function} f A function to call.
+      * @param {boolean} ignoreAbsent If |true|, the error is ignored. Otherwise, the error causes an exception.
       * @return The return value of |f()|
       *
       * This function attempts to get the file matching |id|. If
@@ -160,10 +161,13 @@ if (this.Components) {
      };
 
      let OpenedDirectoryIterators = new ResourceTracker();
-     let withDir = function withDir(fd, f) {
+     let withDir = function withDir(fd, f, ignoreAbsent) {
        let file = OpenedDirectoryIterators.get(fd);
        if (file == null) {
-         throw new Error("Could not find Directory");
+         if (!ignoreAbsent) {
+           throw new Error("Could not find Directory");
+         }
+         return;
        }
        if (!(file instanceof File.DirectoryIterator)) {
          throw new Error("file is not a directory iterator " + file.__proto__.toSource());
@@ -322,7 +326,7 @@ if (this.Components) {
                }
                throw x;
              }
-           });
+           }, false);
        },
        DirectoryIterator_prototype_nextBatch: function nextBatch(dir, size) {
          return withDir(dir,
@@ -335,18 +339,18 @@ if (this.Components) {
                throw x;
              }
              return result.map(File.DirectoryIterator.Entry.toMsg);
-           });
+           }, false);
        },
        DirectoryIterator_prototype_close: function close(dir) {
          return withDir(dir,
            function do_close() {
              this.close();
              OpenedDirectoryIterators.remove(dir);
-           });
+           }, true);// ignore error to support double-closing |DirectoryIterator|
        }
      };
   } catch(ex) {
     dump("WORKER ERROR DURING SETUP " + ex + "\n");
     dump("WORKER ERROR DETAIL " + ex.stack + "\n");
   }
-})(this);
+})(this);

toolkit/components/osfile/tests/mochi/main_test_osfile_async.js

@@ -559,6 +559,12 @@ let test_iter = maketest("iter", function iter(test) {
     yield iterator.close();
     test.info("Closed iterator");
 
+    test.info("Double closing DirectoryIterator");
+    iterator = new OS.File.DirectoryIterator(currentDir);
+    yield iterator.close();
+    yield iterator.close(); //double closing |DirectoryIterator|
+    test.ok(true, "|DirectoryIterator| was closed twice successfully");
+
     let allFiles2 = [];
     let i = 0;
     iterator = new OS.File.DirectoryIterator(currentDir);