Support new-style Mojo JS core API on IOS.

ios/web/webui/resources/support.js

-// Copyright 2016 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.
-
-// Module "mojo/public/js/support"
-//
-// This module provides the JavaScript bindings for mojo/public/c/system/core.h.
-// Refer to that file for more detailed documentation for equivalent methods.
-
-define("mojo/public/js/support", [
-  "ios/mojo/public/js/sync_message_channel",
-  "ios/mojo/public/js/handle_util",
-], function(syncMessageChannel, handleUtil) {
-
-  /**
-   * Holds callbacks for all currently active watches.
-   * @constructor
-   */
-  var MojoWatchCallbacksHolder = function() {
-    /**
-     * Next callback Id to be used for watch.
-     * @private {number}
-     */
-    this.nextCallbackId_ = 0;
-
-    /**
-     * Map where keys are callbacks ids and values are callbacks.
-     * @private {!Map}
-     */
-    this.callbacks_ = new Map();
-
-    /**
-     * Map where keys are watch ids and values are callback ids.
-     * @private {!Map}
-     */
-    this.callbackIds_ = new Map();
-  };
-
-
-  MojoWatchCallbacksHolder.prototype = {
-    /**
-     * Calls watch callback.
-     *
-     * @param {number} callbackId callback id previously returned from
-           {@code getNextCallbackId}.
-     * @param {!MojoResult} mojoResult to call callback with.
-     */
-    callCallback: function(callbackId, mojoResult) {
-      var callback = this.callbackIds_.get(callbackId);
-
-      // Signalling the watch is asynchronous operation and this function may be
-      // called for already removed watch.
-      if (callback)
-        callback(mojoResult);
-    },
-
-    /**
-     * Returns next callback Id to be used for watch (idempotent).
-     *
-     * @return {number} callback id.
-     */
-    getNextCallbackId: function() {
-      return this.nextCallbackId_;
-    },
-
-    /**
-     * Adds callback which must be executed when the Watch fires.
-     *
-     * @param {!MojoWatchId} watchId returned from "support.watch" mojo
-           backend.
-     * @param {!function (mojoResult)} callback which should be executed when
-           the Watch fires.
-     */
-    addWatchCallback: function (watchId, callback) {
-      this.callbackIds_.set(watchId, this.nextCallbackId_);
-      this.callbackIds_.set(this.nextCallbackId_, callback);
-      ++this.nextCallbackId_;
-    },
-
-    /**
-     * Removes callback which should no longer be executed.
-     *
-     * @param {!MojoWatchId} watchId to remove callback for.
-     */
-    removeWatchCallback: function (watchId) {
-      this.callbacks_.delete(this.callbackIds_.get(watchId));
-      this.callbackIds_.delete(watchId);
-    },
-  };
-
-  var watchCallbacksHolder = new MojoWatchCallbacksHolder();
-
-
-  /**
-   * Public functions called by Mojo backend when watch callback fires.
-   * @public {!function(callbackId, mojoResult)}
-   */
-  __crWeb.mojo = {};
-  __crWeb.mojo.signalWatch = function(callbackId, mojoResult) {
-    watchCallbacksHolder.callCallback(callbackId, mojoResult);
-  }
-
- /*
-  * Begins watching a handle for |signals| to be satisfied or unsatisfiable.
-  *
-  * @param {!MojoHandle} handle The handle to watch.
-  * @param {!MojoHandleSignals} signals The signals to watch.
-  * @param {!function (mojoResult)} calback Called with a result any time
-  *     the watched signals become satisfied or unsatisfiable.
-  *
-  * @return {!MojoWatchId} watchId An opaque identifier that identifies this
-  *     watch.
-  */
-  function watch(handle, signals, callback) {
-    var watchId = syncMessageChannel.sendMessage({
-      name: "support.watch",
-      args: {
-         handle: handleUtil.getNativeHandle(handle),
-         signals: signals,
-         callbackId: watchCallbacksHolder.getNextCallbackId()
-      }
-    });
-    watchCallbacksHolder.addWatchCallback(watchId, callback);
-    return watchId;
-  }
-
-  /*
-   * Cancels a handle watch initiated by watch().
-   *
-   * @param {!MojoWatchId} watchId The watch identifier returned by watch().
-   */
-  function cancelWatch(watchId) {
-    syncMessageChannel.sendMessage({
-      name: "support.cancelWatch",
-      args: {
-         watchId: watchId
-      }
-    });
-    watchCallbacksHolder.removeWatchCallback(watchId);
-  }
-
-  var exports = {};
-  exports.watch = watch;
-  exports.cancelWatch = cancelWatch;
-  return exports;
-});