gecko-dev/testing/marionette/dispatcher.js

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6.2 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
const {interfaces: Ci, utils: Cu} = Components;
Cu.import("resource://gre/modules/Log.jsm");
Cu.import("resource://gre/modules/Preferences.jsm");
Cu.import("resource://gre/modules/Task.jsm");
Cu.import("chrome://marionette/content/driver.js");
Cu.import("chrome://marionette/content/error.js");
Cu.import("chrome://marionette/content/message.js");
this.EXPORTED_SYMBOLS = ["Dispatcher"];
const PROTOCOL_VERSION = 3;
const logger = Log.repository.getLogger("Marionette");
/**
* Manages a Marionette connection, and dispatches packets received to
* their correct destinations.
*
* @param {number} connId
* Unique identifier of the connection this dispatcher should handle.
* @param {DebuggerTransport} transport
* Debugger transport connection to the client.
* @param {function(): GeckoDriver} driverFactory
* A factory function that produces a GeckoDriver.
*/
this.Dispatcher = function(connId, transport, driverFactory) {
this.connId = connId;
this.conn = transport;
// transport hooks are Dispatcher#onPacket
// and Dispatcher#onClosed
this.conn.hooks = this;
// callback for when connection is closed
this.onclose = null;
// last received/sent message ID
this.lastId = 0;
this.driver = driverFactory();
// lookup of commands sent by server to client by message ID
this.commands_ = new Map();
};
/**
* Debugger transport callback that cleans up
* after a connection is closed.
*/
Dispatcher.prototype.onClosed = function(reason) {
this.driver.sessionTearDown();
if (this.onclose) {
this.onclose(this);
}
};
/**
* Callback that receives data packets from the client.
*
* If the message is a Response, we look up the command previously issued
* to the client and run its callback, if any. In case of a Command,
* the corresponding is executed.
*
* @param {Array.<number, number, ?, ?>} data
* A four element array where the elements, in sequence, signifies
* message type, message ID, method name or error, and parameters
* or result.
*/
Dispatcher.prototype.onPacket = function(data) {
let msg = Message.fromMsg(data);
msg.origin = MessageOrigin.Client;
this.log_(msg);
if (msg instanceof Response) {
let cmd = this.commands_.get(msg.id);
this.commands_.delete(msg.id);
cmd.onresponse(msg);
} else if (msg instanceof Command) {
this.lastId = msg.id;
this.execute(msg);
}
};
/**
* Executes a WebDriver command and sends back a response when it has
* finished executing.
*
* Commands implemented in GeckoDriver and registered in its
* {@code GeckoDriver.commands} attribute. The return values from
* commands are expected to be Promises. If the resolved value of said
* promise is not an object, the response body will be wrapped in an object
* under a "value" field.
*
* If the command implementation sends the response itself by calling
* {@code resp.send()}, the response is guaranteed to not be sent twice.
*
* Errors thrown in commands are marshaled and sent back, and if they
* are not WebDriverError instances, they are additionally propagated and
* reported to {@code Components.utils.reportError}.
*
* @param {Command} cmd
* The requested command to execute.
*/
Dispatcher.prototype.execute = function(cmd) {
let resp = new Response(cmd.id, this.send.bind(this));
let sendResponse = () => resp.sendConditionally(resp => !resp.sent);
let sendError = resp.sendError.bind(resp);
let req = Task.spawn(function*() {
let fn = this.driver.commands[cmd.name];
if (typeof fn == "undefined") {
throw new UnknownCommandError(cmd.name);
}
let rv = yield fn.bind(this.driver)(cmd, resp);
if (typeof rv != "undefined") {
if (typeof rv != "object") {
resp.body = {value: rv};
} else {
resp.body = rv;
}
}
}.bind(this));
req.then(sendResponse, sendError).catch(error.report);
};
Dispatcher.prototype.sendError = function(err, cmdId) {
let resp = new Response(cmdId, this.send.bind(this));
resp.sendError(err);
};
// Convenience methods:
/**
* When a client connects we send across a JSON Object defining the
* protocol level.
*
* This is the only message sent by Marionette that does not follow
* the regular message format.
*/
Dispatcher.prototype.sayHello = function() {
let whatHo = {
applicationType: "gecko",
marionetteProtocol: PROTOCOL_VERSION,
};
this.sendRaw(whatHo);
};
/**
* Delegates message to client based on the provided {@code cmdId}.
* The message is sent over the debugger transport socket.
*
* The command ID is a unique identifier assigned to the client's request
* that is used to distinguish the asynchronous responses.
*
* Whilst responses to commands are synchronous and must be sent in the
* correct order.
*
* @param {Command,Response} msg
* The command or response to send.
*/
Dispatcher.prototype.send = function(msg) {
msg.origin = MessageOrigin.Server;
if (msg instanceof Command) {
this.commands_.set(msg.id, msg);
this.sendToEmulator(msg);
} else if (msg instanceof Response) {
this.sendToClient(msg);
}
};
// Low-level methods:
/**
* Send given response to the client over the debugger transport socket.
*
* @param {Response} resp
* The response to send back to the client.
*/
Dispatcher.prototype.sendToClient = function(resp) {
this.driver.responseCompleted();
this.sendMessage(resp);
};
/**
* Marshal message to the Marionette message format and send it.
*
* @param {Command,Response} msg
* The message to send.
*/
Dispatcher.prototype.sendMessage = function(msg) {
this.log_(msg);
let payload = msg.toMsg();
this.sendRaw(payload);
};
/**
* Send the given payload over the debugger transport socket to the
* connected client.
*
* @param {Object} payload
* The payload to ship.
*/
Dispatcher.prototype.sendRaw = function(payload) {
this.conn.send(payload);
};
Dispatcher.prototype.log_ = function(msg) {
let a = (msg.origin == MessageOrigin.Client ? " -> " : " <- ");
let s = JSON.stringify(msg.toMsg());
logger.trace(this.connId + a + s);
};