// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This module implements a wrapper for a guestview that manages its
// creation, attaching, and destruction.
var $Document = require('safeMethods').SafeMethods.$Document;
var $HTMLIFrameElement = require('safeMethods').SafeMethods.$HTMLIFrameElement;
var $Node = require('safeMethods').SafeMethods.$Node;
var CreateEvent = require('guestViewEvents').CreateEvent;
var GuestViewInternal = getInternalApi('guestViewInternal');
var GuestViewInternalNatives = requireNative('guest_view_internal');
// Events.
var ResizeEvent = CreateEvent('guestViewInternal.onResize');
// Error messages.
var ERROR_MSG_ALREADY_ATTACHED = 'The guest has already been attached.';
var ERROR_MSG_ALREADY_CREATED = 'The guest has already been created.';
var ERROR_MSG_INVALID_STATE = 'The guest is in an invalid state.';
var ERROR_MSG_NOT_CREATED = 'The guest has not been created.';
// Properties.
var PROPERTY_ON_RESIZE = 'onresize';
var getIframeContentWindow = function(viewInstanceId) {
var view = GuestViewInternalNatives.GetViewFromID(viewInstanceId);
if (!view)
return null;
var internalIframeElement = view.internalElement;
if (internalIframeElement)
return $HTMLIFrameElement.contentWindow.get(internalIframeElement);
return null;
};
// Returns the window object associated with the given view's element.
var getOwnerWindow = function(viewInstanceId) {
var view = GuestViewInternalNatives.GetViewFromID(viewInstanceId);
if (!view) {
return null;
}
var ownerDocument = $Node.ownerDocument.get(view.element);
if (!ownerDocument) {
return null;
}
return $Document.defaultView.get(ownerDocument);
};
// Contains and hides the internal implementation details of |GuestView|,
// including maintaining its state and enforcing the proper usage of its API
// fucntions.
function GuestViewImpl(guestView, viewType, guestInstanceId) {
if (guestInstanceId) {
this.id = guestInstanceId;
this.state = GuestViewImpl.GuestState.GUEST_STATE_CREATED;
} else {
this.id = 0;
this.state = GuestViewImpl.GuestState.GUEST_STATE_START;
}
this.actionQueue = [];
this.contentWindow = null;
this.guestView = guestView;
this.pendingAction = null;
this.viewType = viewType;
this.internalInstanceId = 0;
this.setupOnResize();
}
// Prevent GuestViewImpl inadvertently inheriting code from the global Object,
// allowing a pathway for executing unintended user code execution.
// TODO(wjmaclean): Track down other issues of Object inheritance.
// https://crbug.com/701034
GuestViewImpl.prototype.__proto__ = null;
// Possible states.
GuestViewImpl.GuestState = {
GUEST_STATE_START: 0,
GUEST_STATE_CREATED: 1,
GUEST_STATE_ATTACHED: 2
};
// Sets up the onResize property on the GuestView.
GuestViewImpl.prototype.setupOnResize = function() {
$Object.defineProperty(this.guestView, PROPERTY_ON_RESIZE, {
get: $Function.bind(function() {
return this[PROPERTY_ON_RESIZE];
}, this),
set: $Function.bind(function(value) {
this[PROPERTY_ON_RESIZE] = value;
}, this),
enumerable: true
});
this.callOnResize = $Function.bind(function(e) {
if (!this[PROPERTY_ON_RESIZE]) {
return;
}
this[PROPERTY_ON_RESIZE](e);
}, this);
};
// Callback wrapper that is used to call the callback of the pending action (if
// one exists), and then performs the next action in the queue.
GuestViewImpl.prototype.handleCallback = function(callback) {
if (callback) {
callback();
}
this.pendingAction = null;
this.performNextAction();
};
// Perform the next action in the queue, if one exists.
GuestViewImpl.prototype.performNextAction = function() {
// Make sure that there is not already an action in progress, and that there
// exists a queued action to perform.
if (!this.pendingAction && this.actionQueue.length) {
this.pendingAction = $Array.shift(this.actionQueue);
this.pendingAction();
}
};
// Check the current state to see if the proposed action is valid. Returns false
// if invalid.
GuestViewImpl.prototype.checkState = function(action) {
// Create an error prefix based on the proposed action.
var errorPrefix = 'Error calling ' + action + ': ';
// Check that the current state is valid.
if (!(this.state >= 0 && this.state <= 2)) {
window.console.error(errorPrefix + ERROR_MSG_INVALID_STATE);
return false;
}
// Map of possible errors for each action. For each action, the errors are
// listed for states in the order: GUEST_STATE_START, GUEST_STATE_CREATED,
// GUEST_STATE_ATTACHED.
var errors = {
'attach': [ERROR_MSG_NOT_CREATED, null, ERROR_MSG_ALREADY_ATTACHED],
'create': [null, ERROR_MSG_ALREADY_CREATED, ERROR_MSG_ALREADY_CREATED],
'destroy': [null, null, null],
'setSize': [ERROR_MSG_NOT_CREATED, null, null]
};
// Check that the proposed action is a real action.
if (errors[action] == undefined) {
window.console.error(errorPrefix + ERROR_MSG_INVALID_ACTION);
return false;
}
// Report the error if the proposed action is found to be invalid for the
// current state.
var error;
if (error = errors[action][this.state]) {
window.console.error(errorPrefix + error);
return false;
}
return true;
};
// Returns a wrapper function for |func| with a weak reference to |this|. This
// implementation of weakWrapper() requires a provided |viewInstanceId| since
// GuestViewImpl does not store this ID.
GuestViewImpl.prototype.weakWrapper = function(func, viewInstanceId) {
return function() {
var view = GuestViewInternalNatives.GetViewFromID(viewInstanceId);
if (view && view.guest) {
return $Function.apply(
func, view.guest.internal, $Array.slice(arguments));
}
};
};
// Internal implementation of attach().
GuestViewImpl.prototype.attachImpl = function(
internalInstanceId, viewInstanceId, attachParams, callback) {
var view = GuestViewInternalNatives.GetViewFromID(viewInstanceId);
if (!view.elementAttached) {
// Defer the attachment until the <webview> element is attached.
view.deferredAttachCallback = $Function.bind(this.attachImpl,
this, internalInstanceId, viewInstanceId, attachParams, callback);
return;
};
// Check the current state.
if (!this.checkState('attach')) {
this.handleCallback(callback);
return;
}
// Callback wrapper function to set the contentWindow following attachment,
// and advance the queue.
var callbackWrapper = function(callback) {
var contentWindow = getIframeContentWindow(viewInstanceId);
// Check if attaching failed.
if (!contentWindow) {
this.state = GuestViewImpl.GuestState.GUEST_STATE_CREATED;
this.internalInstanceId = 0;
} else {
// Only update the contentWindow if attaching is successful.
this.contentWindow = contentWindow;
}
this.handleCallback(callback);
};
attachParams['instanceId'] = viewInstanceId;
var contentWindow = getIframeContentWindow(viewInstanceId);
// The internal iframe element may have a null contentWindow at this point.
// For example, we may be trying to attach a guest whose element is in
// another iframe which has already shutdown.
if (!contentWindow) {
this.state = GuestViewImpl.GuestState.GUEST_STATE_CREATED;
this.internalInstanceId = 0;
this.handleCallback(callback);
return;
}
// |contentWindow| is used to retrieve the RenderFrame in cpp.
GuestViewInternalNatives.AttachIframeGuest(
internalInstanceId, this.id, attachParams, contentWindow,
$Function.bind(callbackWrapper, this, callback));
this.internalInstanceId = internalInstanceId;
this.state = GuestViewImpl.GuestState.GUEST_STATE_ATTACHED;
// Detach automatically when the container is destroyed.
GuestViewInternalNatives.RegisterDestructionCallback(
internalInstanceId, this.weakWrapper(function() {
if (this.state != GuestViewImpl.GuestState.GUEST_STATE_ATTACHED ||
this.internalInstanceId != internalInstanceId) {
return;
}
this.internalInstanceId = 0;
this.state = GuestViewImpl.GuestState.GUEST_STATE_CREATED;
}, viewInstanceId));
};
// Internal implementation of create().
GuestViewImpl.prototype.createImpl = function(
viewInstanceId, createParams, callback) {
// Check the current state.
if (!this.checkState('create')) {
this.handleCallback(callback);
return;
}
// Callback wrapper function to store the guestInstanceId from the
// createGuest() callback, handle potential creation failure, and advance the
// queue.
var callbackWrapper = function(callback, instanceId) {
this.id = instanceId;
// Check if creation failed.
if (this.id === 0) {
this.state = GuestViewImpl.GuestState.GUEST_STATE_START;
this.contentWindow = null;
}
ResizeEvent.addListener(this.callOnResize, {instanceId: this.id});
this.handleCallback(callback);
};
// Determine the window which owns the guest view element, so we can inform
// the browser of the prospective owner of the guest.
var ownerWindow = getOwnerWindow(viewInstanceId);
var ownerFrameToken = GuestViewInternalNatives.GetFrameToken(ownerWindow);
GuestViewInternal.createGuest(
this.viewType, ownerFrameToken, createParams,
$Function.bind(callbackWrapper, this, callback));
this.state = GuestViewImpl.GuestState.GUEST_STATE_CREATED;
};
// Internal implementation of destroy().
GuestViewImpl.prototype.destroyImpl = function(callback) {
// Check the current state.
if (!this.checkState('destroy')) {
this.handleCallback(callback);
return;
}
if (this.state == GuestViewImpl.GuestState.GUEST_STATE_START) {
// destroy() does nothing in this case.
this.handleCallback(callback);
return;
}
if (this.state == GuestViewImpl.GuestState.GUEST_STATE_CREATED) {
// If we destroy a guest before attaching it, inform the browser so it can
// clear its associated state. This is only needed for unattached guests,
// since after attachment, the browser knows when to clear the state.
GuestViewInternal.destroyUnattachedGuest(this.id);
}
// Reset the state of the destroyed guest;
this.contentWindow = null;
this.id = 0;
this.internalInstanceId = 0;
this.state = GuestViewImpl.GuestState.GUEST_STATE_START;
if (ResizeEvent.hasListener(this.callOnResize)) {
ResizeEvent.removeListener(this.callOnResize);
}
// Handle callback at end to avoid handling items in the action queue out of
// order, since the callback is run synchronously here.
this.handleCallback(callback);
};
// Internal implementation of setSize().
GuestViewImpl.prototype.setSizeImpl = function(sizeParams, callback) {
// Check the current state.
if (!this.checkState('setSize')) {
this.handleCallback(callback);
return;
}
GuestViewInternal.setSize(
this.id, sizeParams,
$Function.bind(this.handleCallback, this, callback));
};
// The exposed interface to a guestview. Exposes in its API the functions
// attach(), create(), destroy(), and getId(). All other implementation details
// are hidden.
function GuestView(viewType, guestInstanceId) {
this.internal = new GuestViewImpl(this, viewType, guestInstanceId);
}
GuestView.prototype.__proto__ = null;
// Attaches the guestview to the container with ID |internalInstanceId|.
GuestView.prototype.attach = function(
internalInstanceId, viewInstanceId, attachParams, callback) {
var internal = this.internal;
$Array.push(internal.actionQueue, $Function.bind(internal.attachImpl,
internal, internalInstanceId, viewInstanceId, attachParams, callback));
internal.performNextAction();
};
// Creates the guestview.
GuestView.prototype.create = function(viewInstanceId, createParams, callback) {
var internal = this.internal;
$Array.push(
internal.actionQueue,
$Function.bind(
internal.createImpl, internal, viewInstanceId, createParams,
callback));
internal.performNextAction();
};
// Destroys the guestview. Nothing can be done with the guestview after it has
// been destroyed.
GuestView.prototype.destroy = function(callback) {
var internal = this.internal;
$Array.push(
internal.actionQueue,
$Function.bind(internal.destroyImpl, internal, callback));
internal.performNextAction();
};
// Adjusts the guestview's sizing parameters.
GuestView.prototype.setSize = function(sizeParams, callback) {
var internal = this.internal;
$Array.push(internal.actionQueue,
$Function.bind(internal.setSizeImpl, internal, sizeParams, callback));
internal.performNextAction();
};
// Returns the contentWindow for this guestview.
GuestView.prototype.getContentWindow = function() {
var internal = this.internal;
return internal.contentWindow;
};
// Returns the ID for this guestview.
GuestView.prototype.getId = function() {
var internal = this.internal;
return internal.id;
};
// Exports
exports.$set('GuestView', GuestView);
exports.$set('ResizeEvent', ResizeEvent);
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