1 files changed, 52 insertions, 0 deletions
diff --git a/extensions/renderer/resources/entry_id_manager.js b/extensions/renderer/resources/entry_id_manager.js
new file mode 100644
index 0000000..9fc2c14
--- /dev/null
+++ b/extensions/renderer/resources/entry_id_manager.js
@@ -0,0 +1,52 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var fileSystemNatives = requireNative('file_system_natives');
+
+var nameToIds = {};
+var idsToEntries = {};
+
+function computeName(entry) {
+  return entry.filesystem.name + ':' + entry.fullPath;
+}
+
+function computeId(entry) {
+  var fileSystemId = fileSystemNatives.CrackIsolatedFileSystemName(
+      entry.filesystem.name);
+  if (!fileSystemId)
+    return null;
+  // Strip the leading '/' from the path.
+  return fileSystemId + ':' + $String.slice(entry.fullPath, 1);
+}
+
+function registerEntry(id, entry) {
+  var name = computeName(entry);
+  nameToIds[name] = id;
+  idsToEntries[id] = entry;
+}
+
+function getEntryId(entry) {
+  var name = null;
+  try {
+    name = computeName(entry);
+  } catch(e) {
+    return null;
+  }
+  var id = nameToIds[name];
+  if (id != null)
+    return id;
+
+  // If an entry has not been registered, compute its id and register it.
+  id = computeId(entry);
+  registerEntry(id, entry);
+  return id;
+}
+
+function getEntryById(id) {
+  return idsToEntries[id];
+}
+
+exports.registerEntry = registerEntry;
+exports.getEntryId = getEntryId;
+exports.getEntryById = getEntryById;