[fsp] Let extensions decide about the file system id.

chrome/test/data/extensions/api_test/file_system_provider/read_file/test.js

 // 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.
 
 'use strict';
 
 /**
- * @type {number}
- */
-var fileSystemId = 0;
-
-/**
- * @type {?DOMFileSystem}
+ * @type {DOMFileSystem}
  */
 var fileSystem = null;
 
 /**
  * Map of opened files, from a <code>openRequestId</code> to <code>filePath
  * </code>.
  * @type {Object.<number, string>}
  */
 var openedFiles = {};
 
 /**
+ * @type {string}
+ * @const
+ */
+var FILE_SYSTEM_ID = 'chocolate-id';
+
+/**
  * @type {Object}
  * @const
  */
 var TESTING_ROOT = Object.freeze({
   isDirectory: true,
   name: '',
   size: 0,
   modificationTime: new Date(2014, 4, 28, 10, 39, 15)
 });
 
@@ skipping 22 matching lines @@
  * @const
  */
 var TESTING_BROKEN_TIRAMISU_FILE = Object.freeze({
   isDirectory: false,
   name: 'broken-tiramisu.txt',
   size: TESTING_TEXT.length,
   modificationTime: new Date(2014, 1, 25, 7, 36, 12)
 });
 
 /**
+ * Gets volume information for the provided file system.
+ *
+ * @param {string} fileSystemId Id of the provided file system.
+ * @param {function(Object)} callback Callback to be called on result, with the
+ *     volume information object in case of success, or null if not found.
+ */
+function getVolumeInfo(fileSystemId, callback) {
+  chrome.fileBrowserPrivate.getVolumeMetadataList(function(volumeList) {
+    for (var i = 0; i < volumeList.length; i++) {
+      if (volumeList[i].extensionId == chrome.runtime.id &&
+          volumeList[i].fileSystemId == fileSystemId) {
+        callback(volumeList[i]);
+        return;
+      }
+    }
+    callback(null);
+  });
+}
+
+/**
  * Returns metadata for the requested entry.
  *
  * To successfully acquire a DirectoryEntry, or even a DOMFileSystem, this event
  * must be implemented and return correct values.
  *
  * @param {number} inFileSystemId ID of the file system.

[hirono, 2014/05/21 10:09:54]

nit: string
Same for followings.

[mtomasz, 2014/05/22 02:16:54]

Done.

  * @param {string} entryPath Path of the requested entry.
  * @param {function(Object)} onSuccess Success callback with metadata passed
  *     an argument.
  * @param {function(string)} onError Error callback with an error code.
  */
 function onGetMetadataRequested(
     inFileSystemId, entryPath, onSuccess, onError) {
-  if (inFileSystemId != fileSystemId) {
+  if (inFileSystemId != FILE_SYSTEM_ID) {
     onError('SECURITY_ERROR');  // enum ProviderError.
     return;
   }
 
   if (entryPath == '/') {
     onSuccess(TESTING_ROOT);
     return;
   }
 
   if (entryPath == '/' + TESTING_TIRAMISU_FILE.name) {
@@ skipping 16 matching lines @@
  * @param {number} inFileSystemId ID of the file system.
  * @param {number} requestId ID of the opening request. Used later for reading.
  * @param {string} filePath Path of the file to be opened.
  * @param {string} mode Mode, either reading or writing.
  * @param {boolean} create True to create if doesn't exist.
  * @param {function()} onSuccess Success callback.
  * @param {function(string)} onError Error callback.
  */
 function onOpenFileRequested(
     inFileSystemId, requestId, filePath, mode, create, onSuccess, onError) {
-  if (inFileSystemId != fileSystemId || mode != 'READ' || create) {
+  if (inFileSystemId != FILE_SYSTEM_ID || mode != 'READ' || create) {
     onError('SECURITY_ERROR');  // enum ProviderError.
     return;
   }
 
   if (filePath == '/' + TESTING_TIRAMISU_FILE.name ||
       filePath == '/' + TESTING_BROKEN_TIRAMISU_FILE.name) {
     openedFiles[requestId] = filePath;
     onSuccess();
   } else {
     onError('NOT_FOUND');  // enum ProviderError.
   }
 }
 
 /**
  * Requests closing a file previously opened with <code>openRequestId</code>.
  *
  * @param {number} inFileSystemId ID of the file system.
  * @param {number} openRequestId ID of the request used to open the file.
  * @param {function()} onSuccess Success callback.
  * @param {function(string)} onError Error callback.
  */
 function onCloseFileRequested(
     inFileSystemId, openRequestId, onSuccess, onError) {
-  if (inFileSystemId != fileSystemId || !openedFiles[openRequestId]) {
+  if (inFileSystemId != FILE_SYSTEM_ID || !openedFiles[openRequestId]) {
     onError('SECURITY_ERROR');  // enum ProviderError.
     return;
   }
 
   delete openedFiles[requestId];
   onSuccess();
 }
 
 /**
  * Requests reading contents of a file, previously opened with <code>
  * openRequestId</code>.
  *
  * @param {number} inFileSystemId ID of the file system.
  * @param {number} openRequestId ID of the request used to open the file.
  * @param {number} offset Offset of the file.
  * @param {number} length Number of bytes to read.
  * @param {function(ArrayBuffer, boolean)} onSuccess Success callback with a
  *     chunk of data, and information if more data will be provided later.
  * @param {function(string)} onError Error callback.
  */
 function onReadFileRequested(
     inFileSystemId, openRequestId, offset, length, onSuccess, onError) {
   var filePath = openedFiles[openRequestId];
-  if (inFileSystemId != fileSystemId || !filePath) {
+  if (inFileSystemId != FILE_SYSTEM_ID || !filePath) {
     onError('SECURITY_ERROR');  // enum ProviderError.
     return;
   }
 
   if (filePath == '/' + TESTING_TIRAMISU_FILE.name) {
     var textToSend = TESTING_TEXT.substr(offset, length);
     var textToSendInChunks = textToSend.split(/(?= )/);
 
     textToSendInChunks.forEach(function(item, index) {
       // Convert item (string) to an ArrayBuffer.
@@ skipping 18 matching lines @@
   onError('INVALID_OPERATION');  // enum ProviderError.
 }
 
 /**
  * Sets up the tests. Called once per all test cases. In case of a failure,
  * the callback is not called.
  *
  * @param {function()} callback Success callback.
  */
 function setUp(callback) {
-  chrome.fileSystemProvider.mount('chocolate.zip', function(id) {
-    fileSystemId = id;
+  chrome.fileSystemProvider.mount(FILE_SYSTEM_ID, 'chocolate.zip', function() {
     chrome.fileSystemProvider.onGetMetadataRequested.addListener(
         onGetMetadataRequested);
     chrome.fileSystemProvider.onOpenFileRequested.addListener(
         onOpenFileRequested);
     chrome.fileSystemProvider.onReadFileRequested.addListener(
         onReadFileRequested);
     var volumeId =
-        'provided:' + chrome.runtime.id + '-' + fileSystemId + '-user';
+        'provided:' + chrome.runtime.id + '-' + FILE_SYSTEM_ID + '-user';
 
-    chrome.fileBrowserPrivate.requestFileSystem(
-        volumeId,
-        function(inFileSystem) {
-          chrome.test.assertTrue(!!inFileSystem);
+    getVolumeInfo(FILE_SYSTEM_ID, function(volumeInfo) {
+      chrome.test.assertTrue(!!volumeInfo);
+      chrome.fileBrowserPrivate.requestFileSystem(
+          volumeInfo.volumeId,
+          function(inFileSystem) {
+            chrome.test.assertTrue(!!inFileSystem);
 
-          fileSystem = inFileSystem;
-          callback();
-        });
+            fileSystem = inFileSystem;
+            callback();
+          });
+    });
   }, function() {
     chrome.test.fail();
   });
 }
 
 /**
  * Runs all of the test cases, one by one.
  */
 function runTests() {
   chrome.test.runTests([
@@ skipping 50 matching lines @@
           },
           function(error) {
             chrome.test.fail(error.name);
           });
     }
   ]);
 }
 
 // Setup and run all of the test cases.
 setUp(runTests);