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Bug 1560445 - Extract classes from protocol.js. r=yulia

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Differential Revision: https://phabricator.services.mozilla.com/D35502

--HG--
rename : devtools/shared/protocol.js => devtools/shared/protocol/Actor.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/Actor/generateActorSpec.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/Front.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/Front/FrontClassWithSpec.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/Pool.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/Request.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/Response.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/types.js
rename : devtools/shared/protocol.js => devtools/shared/protocol/utils.js
extra : moz-landing-system : lando
This commit is contained in:
Jason Laster 2019-06-26 15:53:20 +00:00
parent 9f81e46a34
commit 890892c4e2
13 changed files with 1776 additions and 1623 deletions
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1653
devtools/shared/protocol.js
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"use strict";
const { extend } = require("devtools/shared/extend");
var { Pool } = require("./Pool");
/**
* Keep track of which actorSpecs have been created. If a replica of a spec
* is created, it can be caught, and specs which inherit from other specs will
* not overwrite eachother.
*/
var actorSpecs = new WeakMap();
exports.actorSpecs = actorSpecs;
/**
* An actor in the actor tree.
*
* @param optional conn
* Either a DebuggerServerConnection or a DebuggerClient. Must have
* addActorPool, removeActorPool, and poolFor.
* conn can be null if the subclass provides a conn property.
* @constructor
*/
class Actor extends Pool {
// Existing Actors extending this class expect initialize to contain constructor logic.
initialize(conn) {
// Repeat Pool.constructor here as we can't call it from initialize
// This is to be removed once actors switch to es classes and are able to call
// Actor's contructor.
if (conn) {
this.conn = conn;
}
// Will contain the actor's ID
this.actorID = null;
this._actorSpec = actorSpecs.get(Object.getPrototypeOf(this));
// Forward events to the connection.
if (this._actorSpec && this._actorSpec.events) {
for (const [name, request] of this._actorSpec.events.entries()) {
this.on(name, (...args) => {
this._sendEvent(name, request, ...args);
});
}
}
}
toString() {
return "[Actor " + this.typeName + "/" + this.actorID + "]";
}
_sendEvent(name, request, ...args) {
if (!this.actorID) {
console.error(`Tried to send a '${name}' event on an already destroyed actor` +
` '${this.typeName}'`);
return;
}
let packet;
try {
packet = request.write(args, this);
} catch (ex) {
console.error("Error sending event: " + name);
throw ex;
}
packet.from = packet.from || this.actorID;
this.conn.send(packet);
}
destroy() {
super.destroy();
this.actorID = null;
}
/**
* Override this method in subclasses to serialize the actor.
* @param [optional] string hint
* Optional string to customize the form.
* @returns A jsonable object.
*/
form(hint) {
return { actor: this.actorID };
}
writeError(error, typeName, method) {
console.error(`Error while calling actor '${typeName}'s method '${method}'`,
error.message);
if (error.stack) {
console.error(error.stack);
}
this.conn.send({
from: this.actorID,
error: error.error || "unknownError",
message: error.message,
});
}
_queueResponse(create) {
const pending = this._pendingResponse || Promise.resolve(null);
const response = create(pending);
this._pendingResponse = response;
}
/**
* Throw an error with the passed message and attach an `error` property to the Error
* object so it can be consumed by the writeError function.
* @param {String} error: A string (usually a single word serving as an id) that will
* be assign to error.error.
* @param {String} message: The string that will be passed to the Error constructor.
* @throws This always throw.
*/
throwError(error, message) {
const err = new Error(message);
err.error = error;
throw err;
}
}
exports.Actor = Actor;
/**
* Generates request handlers as described by the given actor specification on
* the given actor prototype. Returns the actor prototype.
*/
var generateRequestHandlers = function(actorSpec, actorProto) {
actorProto.typeName = actorSpec.typeName;
// Generate request handlers for each method definition
actorProto.requestTypes = Object.create(null);
actorSpec.methods.forEach(spec => {
const handler = function(packet, conn) {
try {
let args;
try {
args = spec.request.read(packet, this);
} catch (ex) {
console.error("Error reading request: " + packet.type);
throw ex;
}
if (!this[spec.name]) {
throw new Error(
`Spec for '${actorProto.typeName}' specifies a '${spec.name}'` +
` method that isn't implemented by the actor`
);
}
const ret = this[spec.name].apply(this, args);
const sendReturn = retToSend => {
if (spec.oneway) {
// No need to send a response.
return;
}
let response;
try {
response = spec.response.write(retToSend, this);
} catch (ex) {
console.error("Error writing response to: " + spec.name);
throw ex;
}
response.from = this.actorID;
// If spec.release has been specified, destroy the object.
if (spec.release) {
try {
this.destroy();
} catch (e) {
this.writeError(e, actorProto.typeName, spec.name);
return;
}
}
conn.send(response);
};
this._queueResponse(p => {
return p
.then(() => ret)
.then(sendReturn)
.catch(e => this.writeError(e, actorProto.typeName, spec.name));
});
} catch (e) {
this._queueResponse(p => {
return p.then(() =>
this.writeError(e, actorProto.typeName, spec.name)
);
});
}
};
actorProto.requestTypes[spec.request.type] = handler;
});
return actorProto;
};
/**
* Create an actor class for the given actor specification and prototype.
*
* @param object actorSpec
* The actor specification. Must have a 'typeName' property.
* @param object actorProto
* The actor prototype. Should have method definitions, can have event
* definitions.
*/
var ActorClassWithSpec = function(actorSpec, actorProto) {
if (!actorSpec.typeName) {
throw Error("Actor specification must have a typeName member.");
}
// Existing Actors are relying on the initialize instead of constructor methods.
const cls = function() {
const instance = Object.create(cls.prototype);
instance.initialize.apply(instance, arguments);
return instance;
};
cls.prototype = extend(
Actor.prototype,
generateRequestHandlers(actorSpec, actorProto)
);
actorSpecs.set(cls.prototype, actorSpec);
return cls;
};
exports.ActorClassWithSpec = ActorClassWithSpec;

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"use strict";
var { Request } = require("../Request");
const { Response } = require("../Response");
var { types, registeredTypes } = require("../types");
/**
* Generates an actor specification from an actor description.
*/
var generateActorSpec = function(actorDesc) {
const actorSpec = {
typeName: actorDesc.typeName,
methods: [],
};
// Find method and form specifications attached to properties.
for (const name of Object.getOwnPropertyNames(actorDesc)) {
const desc = Object.getOwnPropertyDescriptor(actorDesc, name);
if (!desc.value) {
continue;
}
if (desc.value._methodSpec) {
const methodSpec = desc.value._methodSpec;
const spec = {};
spec.name = methodSpec.name || name;
spec.request = new Request(
Object.assign({ type: spec.name }, methodSpec.request || undefined)
);
spec.response = new Response(methodSpec.response || undefined);
spec.release = methodSpec.release;
spec.oneway = methodSpec.oneway;
actorSpec.methods.push(spec);
}
}
// Find additional method specifications
if (actorDesc.methods) {
for (const name in actorDesc.methods) {
const methodSpec = actorDesc.methods[name];
const spec = {};
spec.name = methodSpec.name || name;
spec.request = new Request(
Object.assign({ type: spec.name }, methodSpec.request || undefined)
);
spec.response = new Response(methodSpec.response || undefined);
spec.release = methodSpec.release;
spec.oneway = methodSpec.oneway;
actorSpec.methods.push(spec);
}
}
// Find event specifications
if (actorDesc.events) {
actorSpec.events = new Map();
for (const name in actorDesc.events) {
const eventRequest = actorDesc.events[name];
Object.freeze(eventRequest);
actorSpec.events.set(
name,
new Request(Object.assign({ type: name }, eventRequest))
);
}
}
if (!registeredTypes.has(actorSpec.typeName)) {
types.addActorType(actorSpec.typeName);
}
registeredTypes.get(actorSpec.typeName).actorSpec = actorSpec;
return actorSpec;
};
exports.generateActorSpec = generateActorSpec;

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# vim: set filetype=python:
# 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/.
DevToolsModules(
'generateActorSpec.js',
)

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"use strict";
var { settleAll } = require("devtools/shared/DevToolsUtils");
var EventEmitter = require("devtools/shared/event-emitter");
var { Pool } = require("./Pool");
var {
getStack,
callFunctionWithAsyncStack,
} = require("devtools/shared/platform/stack");
// Bug 1454373: devtools/shared/defer still uses Promise.jsm which is slower
// than DOM Promises. So implement our own copy of `defer` based on DOM Promises.
function defer() {
let resolve, reject;
const promise = new Promise(function() {
resolve = arguments[0];
reject = arguments[1];
});
return {
resolve: resolve,
reject: reject,
promise: promise,
};
}
/**
* Base class for client-side actor fronts.
*
* @param optional conn
* Either a DebuggerServerConnection or a DebuggerClient. Must have
* addActorPool, removeActorPool, and poolFor.
* conn can be null if the subclass provides a conn property.
* @constructor
*/
class Front extends Pool {
constructor(conn = null) {
super(conn);
this.actorID = null;
this._requests = [];
// Front listener functions registered via `onFront` get notified
// of new fronts via this dedicated EventEmitter object.
this._frontListeners = new EventEmitter();
// List of optional listener for each event, that is processed immediatly on packet
// receival, before emitting event via EventEmitter on the Front.
// These listeners are register via Front.before function.
// Map(Event Name[string] => Event Listener[function])
this._beforeListeners = new Map();
}
destroy() {
// Reject all outstanding requests, they won't make sense after
// the front is destroyed.
while (this._requests && this._requests.length > 0) {
const { deferred, to, type, stack } = this._requests.shift();
const msg =
"Connection closed, pending request to " +
to +
", type " +
type +
" failed" +
"\n\nRequest stack:\n" +
stack.formattedStack;
deferred.reject(new Error(msg));
}
super.destroy();
this.clearEvents();
this.actorID = null;
this._frontListeners = null;
this._beforeListeners = null;
}
manage(front) {
if (!front.actorID) {
throw new Error(
"Can't manage front without an actor ID.\n" +
"Ensure server supports " +
front.typeName +
"."
);
}
super.manage(front);
// Call listeners registered via `onFront` method
this._frontListeners.emit(front.typeName, front);
}
// Run callback on every front of this type that currently exists, and on every
// instantiation of front type in the future.
onFront(typeName, callback) {
// First fire the callback on already instantiated fronts
for (const front of this.poolChildren()) {
if (front.typeName == typeName) {
callback(front);
}
}
// Then register the callback for fronts instantiated in the future
this._frontListeners.on(typeName, callback);
}
/**
* Register an event listener that will be called immediately on packer receival.
* The given callback is going to be called before emitting the event via EventEmitter
* API on the Front. Event emitting will be delayed if the callback is async.
* Only one such listener can be registered per type of event.
*
* @param String type
* Event emitted by the actor to intercept.
* @param Function callback
* Function that will process the event.
*/
before(type, callback) {
if (this._beforeListeners.has(type)) {
throw new Error(
`Can't register multiple before listeners for "${type}".`
);
}
this._beforeListeners.set(type, callback);
}
toString() {
return "[Front for " + this.typeName + "/" + this.actorID + "]";
}
/**
* Update the actor from its representation.
* Subclasses should override this.
*/
form(form) {}
/**
* Send a packet on the connection.
*/
send(packet) {
if (packet.to) {
this.conn._transport.send(packet);
} else {
packet.to = this.actorID;
// The connection might be closed during the promise resolution
if (this.conn._transport) {
this.conn._transport.send(packet);
}
}
}
/**
* Send a two-way request on the connection.
*/
request(packet) {
const deferred = defer();
// Save packet basics for debugging
const { to, type } = packet;
this._requests.push({
deferred,
to: to || this.actorID,
type,
stack: getStack(),
});
this.send(packet);
return deferred.promise;
}
/**
* Handler for incoming packets from the client's actor.
*/
onPacket(packet) {
// Pick off event packets
const type = packet.type || undefined;
if (this._clientSpec.events && this._clientSpec.events.has(type)) {
const event = this._clientSpec.events.get(packet.type);
let args;
try {
args = event.request.read(packet, this);
} catch (ex) {
console.error("Error reading event: " + packet.type);
console.exception(ex);
throw ex;
}
// Check for "pre event" callback to be processed before emitting events on fronts
// Use event.name instead of packet.type to use specific event name instead of RDP
// packet's type.
const beforeEvent = this._beforeListeners.get(event.name);
if (beforeEvent) {
const result = beforeEvent.apply(this, args);
// Check to see if the beforeEvent returned a promise -- if so,
// wait for their resolution before emitting. Otherwise, emit synchronously.
if (result && typeof result.then == "function") {
result.then(() => {
super.emit(event.name, ...args);
});
return;
}
}
super.emit(event.name, ...args);
return;
}
// Remaining packets must be responses.
if (this._requests.length === 0) {
const msg =
"Unexpected packet " + this.actorID + ", " + JSON.stringify(packet);
const err = Error(msg);
console.error(err);
throw err;
}
const { deferred, stack } = this._requests.shift();
callFunctionWithAsyncStack(
() => {
if (packet.error) {
// "Protocol error" is here to avoid TBPL heuristics. See also
// https://dxr.mozilla.org/webtools-central/source/tbpl/php/inc/GeneralErrorFilter.php
let message;
if (packet.error && packet.message) {
message =
"Protocol error (" + packet.error + "): " + packet.message;
} else {
message = packet.error;
}
deferred.reject(message);
} else {
deferred.resolve(packet);
}
},
stack,
"DevTools RDP"
);
}
hasRequests() {
return !!this._requests.length;
}
/**
* Wait for all current requests from this front to settle. This is especially useful
* for tests and other utility environments that may not have events or mechanisms to
* await the completion of requests without this utility.
*
* @return Promise
* Resolved when all requests have settled.
*/
waitForRequestsToSettle() {
return settleAll(this._requests.map(({ deferred }) => deferred.promise));
}
}
exports.Front = Front;

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"use strict";
var { Front } = require("../Front");
/**
* Generates request methods as described by the given actor specification on
* the given front prototype. Returns the front prototype.
*/
var generateRequestMethods = function(actorSpec, frontProto) {
if (frontProto._actorSpec) {
throw new Error("frontProto called twice on the same front prototype!");
}
frontProto.typeName = actorSpec.typeName;
// Generate request methods.
const methods = actorSpec.methods;
methods.forEach(spec => {
const name = spec.name;
frontProto[name] = function(...args) {
// If this.actorID are not available, the request will not be able to complete.
// The front was probably destroyed earlier.
if (!this.actorID) {
throw new Error(
`Can not send request because front '${
this.typeName
}' is already destroyed.`
);
}
let packet;
try {
packet = spec.request.write(args, this);
} catch (ex) {
console.error("Error writing request: " + name);
throw ex;
}
if (spec.oneway) {
// Fire-and-forget oneway packets.
this.send(packet);
return undefined;
}
return this.request(packet).then(response => {
let ret;
try {
ret = spec.response.read(response, this);
} catch (ex) {
console.error("Error reading response to: " + name + "\n" + ex);
throw ex;
}
return ret;
});
};
// Release methods should call the destroy function on return.
if (spec.release) {
const fn = frontProto[name];
frontProto[name] = function(...args) {
return fn.apply(this, args).then(result => {
this.destroy();
return result;
});
};
}
});
// Process event specifications
frontProto._clientSpec = {};
const actorEvents = actorSpec.events;
if (actorEvents) {
frontProto._clientSpec.events = new Map();
for (const [name, request] of actorEvents) {
frontProto._clientSpec.events.set(request.type, {
name,
request,
});
}
}
frontProto._actorSpec = actorSpec;
return frontProto;
};
/**
* Create a front class for the given actor specification and front prototype.
*
* @param object actorSpec
* The actor specification you're creating a front for.
* @param object proto
* The object prototype. Must have a 'typeName' property,
* should have method definitions, can have event definitions.
*/
var FrontClassWithSpec = function(actorSpec) {
class OneFront extends Front {}
generateRequestMethods(actorSpec, OneFront.prototype);
return OneFront;
};
exports.FrontClassWithSpec = FrontClassWithSpec;

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# vim: set filetype=python:
# 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/.
DevToolsModules(
'FrontClassWithSpec.js',
)

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"use strict";
var EventEmitter = require("devtools/shared/event-emitter");
/**
* Actor and Front implementations
*/
/**
* A protocol object that can manage the lifetime of other protocol
* objects. Pools are used on both sides of the connection to help coordinate lifetimes.
*
* @param optional conn
* Either a DebuggerServerConnection or a DebuggerClient. Must have
* addActorPool, removeActorPool, and poolFor.
* conn can be null if the subclass provides a conn property.
* @constructor
*/
class Pool extends EventEmitter {
constructor(conn) {
super();
if (conn) {
this.conn = conn;
}
this.__poolMap = null;
}
/**
* Return the parent pool for this client.
*/
parent() {
return this.conn.poolFor(this.actorID);
}
poolFor(actorID) {
return this.conn.poolFor(actorID);
}
/**
* Override this if you want actors returned by this actor
* to belong to a different actor by default.
*/
marshallPool() {
return this;
}
/**
* Pool is the base class for all actors, even leaf nodes.
* If the child map is actually referenced, go ahead and create
* the stuff needed by the pool.
*/
get _poolMap() {
if (this.__poolMap) {
return this.__poolMap;
}
this.__poolMap = new Map();
this.conn.addActorPool(this);
return this.__poolMap;
}
/**
* Add an actor as a child of this pool.
*/
manage(actor) {
if (!actor.actorID) {
actor.actorID = this.conn.allocID(actor.actorPrefix || actor.typeName);
} else {
// If the actor is already registerd in a pool, remove it without destroying it.
// This happens for example when an addon is reloaded. To see this behavior, take a
// look at devtools/server/tests/unit/test_addon_reload.js
// TODO: not all actors have been moved to protocol.js, so they do not all have
// a parent field. Remove the check for the parent once the conversion is finished
const parent = this.poolFor(actor.actorID);
if (parent) {
parent.unmanage(actor);
}
}
this._poolMap.set(actor.actorID, actor);
}
/**
* Remove an actor as a child of this pool.
*/
unmanage(actor) {
this.__poolMap && this.__poolMap.delete(actor.actorID);
}
// true if the given actor ID exists in the pool.
has(actorID) {
return this.__poolMap && this._poolMap.has(actorID);
}
// The actor for a given actor id stored in this pool
actor(actorID) {
if (this.__poolMap) {
return this._poolMap.get(actorID);
}
return null;
}
// Same as actor, should update debugger connection to use 'actor'
// and then remove this.
get(actorID) {
if (this.__poolMap) {
return this._poolMap.get(actorID);
}
return null;
}
// True if this pool has no children.
isEmpty() {
return !this.__poolMap || this._poolMap.size == 0;
}
// Generator that yields each non-self child of the pool.
* poolChildren() {
if (!this.__poolMap) {
return;
}
for (const actor of this.__poolMap.values()) {
// Self-owned actors are ok, but don't need visiting twice.
if (actor === this) {
continue;
}
yield actor;
}
}
/**
* Destroy this item, removing it from a parent if it has one,
* and destroying all children if necessary.
*/
destroy() {
const parent = this.parent();
if (parent) {
parent.unmanage(this);
}
if (!this.__poolMap) {
return;
}
for (const actor of this.__poolMap.values()) {
// Self-owned actors are ok, but don't need destroying twice.
if (actor === this) {
continue;
}
const destroy = actor.destroy;
if (destroy) {
// Disconnect destroy while we're destroying in case of (misbehaving)
// circular ownership.
actor.destroy = null;
destroy.call(actor);
actor.destroy = destroy;
}
}
this.conn.removeActorPool(this, true);
this.__poolMap.clear();
this.__poolMap = null;
}
/**
* For getting along with the debugger server pools, should be removable
* eventually.
*/
cleanup() {
this.destroy();
}
}
exports.Pool = Pool;

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"use strict";
const { extend } = require("devtools/shared/extend");
var { findPlaceholders, describeTemplate, getPath } = require("./utils");
var { types } = require("./types");
/**
* Manages a request template.
*
* @param object template
* The request template.
* @construcor
*/
var Request = function(template = {}) {
this.type = template.type;
this.template = template;
this.args = findPlaceholders(template, Arg);
};
Request.prototype = {
/**
* Write a request.
*
* @param array fnArgs
* The function arguments to place in the request.
* @param object ctx
* The object making the request.
* @returns a request packet.
*/
write: function(fnArgs, ctx) {
const ret = {};
for (const key in this.template) {
const value = this.template[key];
if (value instanceof Arg) {
ret[key] = value.write(
value.index in fnArgs ? fnArgs[value.index] : undefined,
ctx,
key
);
} else if (key == "type") {
ret[key] = value;
} else {
throw new Error(
"Request can only an object with `Arg` or `Option` properties"
);
}
}
return ret;
},
/**
* Read a request.
*
* @param object packet
* The request packet.
* @param object ctx
* The object making the request.
* @returns an arguments array
*/
read: function(packet, ctx) {
const fnArgs = [];
for (const templateArg of this.args) {
const arg = templateArg.placeholder;
const path = templateArg.path;
const name = path[path.length - 1];
arg.read(getPath(packet, path), ctx, fnArgs, name);
}
return fnArgs;
},
describe: function() {
return describeTemplate(this.template);
},
};
exports.Request = Request;
/**
* Request/Response templates and generation
*
* Request packets are specified as json templates with
* Arg and Option placeholders where arguments should be
* placed.
*
* Reponse packets are also specified as json templates,
* with a RetVal placeholder where the return value should be
* placed.
*/
/**
* Placeholder for simple arguments.
*
* @param number index
* The argument index to place at this position.
* @param type type
* The argument should be marshalled as this type.
* @constructor
*/
var Arg = function(index, type) {
this.index = index;
// Prevent force loading all Arg types by accessing it only when needed
loader.lazyGetter(this, "type", function() {
return types.getType(type);
});
};
Arg.prototype = {
write: function(arg, ctx) {
return this.type.write(arg, ctx);
},
read: function(v, ctx, outArgs) {
outArgs[this.index] = this.type.read(v, ctx);
},
describe: function() {
return {
_arg: this.index,
type: this.type.name,
};
},
};
// Outside of protocol.js, Arg is called as factory method, without the new keyword.
exports.Arg = function(index, type) {
return new Arg(index, type);
};
/**
* Placeholder for an options argument value that should be hoisted
* into the packet.
*
* If provided in a method specification:
*
* { optionArg: Option(1)}
*
* Then arguments[1].optionArg will be placed in the packet in this
* value's place.
*
* @param number index
* The argument index of the options value.
* @param type type
* The argument should be marshalled as this type.
* @constructor
*/
var Option = function(index, type) {
Arg.call(this, index, type);
};
Option.prototype = extend(Arg.prototype, {
write: function(arg, ctx, name) {
// Ignore if arg is undefined or null; allow other falsy values
if (arg == undefined || arg[name] == undefined) {
return undefined;
}
const v = arg[name];
return this.type.write(v, ctx);
},
read: function(v, ctx, outArgs, name) {
if (outArgs[this.index] === undefined) {
outArgs[this.index] = {};
}
if (v === undefined) {
return;
}
outArgs[this.index][name] = this.type.read(v, ctx);
},
describe: function() {
return {
_option: this.index,
type: this.type.name,
};
},
});
// Outside of protocol.js, Option is called as factory method, without the new keyword.
exports.Option = function(index, type) {
return new Option(index, type);
};

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"use strict";
var { findPlaceholders, getPath, describeTemplate } = require("./utils");
var { types } = require("./types");
/**
* Manages a response template.
*
* @param object template
* The response template.
* @construcor
*/
var Response = function(template = {}) {
this.template = template;
const placeholders = findPlaceholders(template, RetVal);
if (placeholders.length > 1) {
throw Error("More than one RetVal specified in response");
}
const placeholder = placeholders.shift();
if (placeholder) {
this.retVal = placeholder.placeholder;
this.path = placeholder.path;
}
};
Response.prototype = {
/**
* Write a response for the given return value.
*
* @param val ret
* The return value.
* @param object ctx
* The object writing the response.
*/
write: function(ret, ctx) {
// Consider that `template` is either directly a `RetVal`,
// or a dictionary with may be one `RetVal`.
if (this.template instanceof RetVal) {
return this.template.write(ret, ctx);
}
const result = {};
for (const key in this.template) {
const value = this.template[key];
if (value instanceof RetVal) {
result[key] = value.write(ret, ctx);
} else {
throw new Error(
"Response can only be a `RetVal` instance or an object " +
"with one property being a `RetVal` instance."
);
}
}
return result;
},
/**
* Read a return value from the given response.
*
* @param object packet
* The response packet.
* @param object ctx
* The object reading the response.
*/
read: function(packet, ctx) {
if (!this.retVal) {
return undefined;
}
const v = getPath(packet, this.path);
return this.retVal.read(v, ctx);
},
describe: function() {
return describeTemplate(this.template);
},
};
exports.Response = Response;
/**
* Placeholder for return values in a response template.
*
* @param type type
* The return value should be marshalled as this type.
*/
var RetVal = function(type) {
// Prevent force loading all RetVal types by accessing it only when needed
loader.lazyGetter(this, "type", function() {
return types.getType(type);
});
};
RetVal.prototype = {
write: function(v, ctx) {
return this.type.write(v, ctx);
},
read: function(v, ctx) {
return this.type.read(v, ctx);
},
describe: function() {
return {
_retval: this.type.name,
};
},
};
// Outside of protocol.js, RetVal is called as factory method, without the new keyword.
exports.RetVal = function(type) {
return new RetVal(type);
};

13
devtools/shared/protocol/moz.build
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@ -1,9 +1,20 @@
# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
# vim: set filetype=python:
# 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/.
DIRS += [
'Actor',
'Front',
]
DevToolsModules(
'Actor.js',
'Front.js',
'lazy-pool.js',
'Pool.js',
'Request.js',
'Response.js',
'types.js',
'utils.js',
)

525
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"use strict";
var { Actor } = require("./Actor");
var { lazyLoadSpec, lazyLoadFront } = require("devtools/shared/specs/index");
/**
* Types: named marshallers/demarshallers.
*
* Types provide a 'write' function that takes a js representation and
* returns a protocol representation, and a "read" function that
* takes a protocol representation and returns a js representation.
*
* The read and write methods are also passed a context object that
* represent the actor or front requesting the translation.
*
* Types are referred to with a typestring. Basic types are
* registered by name using addType, and more complex types can
* be generated by adding detail to the type name.
*/
var types = Object.create(null);
exports.types = types;
var registeredTypes = (types.registeredTypes = new Map());
var registeredLifetimes = (types.registeredLifetimes = new Map());
exports.registeredTypes = registeredTypes;
/**
* Return the type object associated with a given typestring.
* If passed a type object, it will be returned unchanged.
*
* Types can be registered with addType, or can be created on
* the fly with typestrings. Examples:
*
* boolean
* threadActor
* threadActor#detail
* array:threadActor
* array:array:threadActor#detail
*
* @param [typestring|type] type
* Either a typestring naming a type or a type object.
*
* @returns a type object.
*/
types.getType = function(type) {
if (!type) {
return types.Primitive;
}
if (typeof type !== "string") {
return type;
}
// If already registered, we're done here.
let reg = registeredTypes.get(type);
if (reg) {
return reg;
}
// Try to lazy load the spec, if not already loaded.
if (lazyLoadSpec(type)) {
// If a spec module was lazy loaded, it will synchronously call
// generateActorSpec, and set the type in `registeredTypes`.
reg = registeredTypes.get(type);
if (reg) {
return reg;
}
}
// New type, see if it's a collection/lifetime type:
const sep = type.indexOf(":");
if (sep >= 0) {
const collection = type.substring(0, sep);
const subtype = types.getType(type.substring(sep + 1));
if (collection === "array") {
return types.addArrayType(subtype);
} else if (collection === "nullable") {
return types.addNullableType(subtype);
}
if (registeredLifetimes.has(collection)) {
return types.addLifetimeType(collection, subtype);
}
throw Error("Unknown collection type: " + collection);
}
// Not a collection, might be actor detail
const pieces = type.split("#", 2);
if (pieces.length > 1) {
if (pieces[1] != "actorid") {
throw new Error(
"Unsupported detail, only support 'actorid', got: " + pieces[1]
);
}
return types.addActorDetail(type, pieces[0], pieces[1]);
}
throw Error("Unknown type: " + type);
};
/**
* Don't allow undefined when writing primitive types to packets. If
* you want to allow undefined, use a nullable type.
*/
function identityWrite(v) {
if (v === undefined) {
throw Error("undefined passed where a value is required");
}
// This has to handle iterator->array conversion because arrays of
// primitive types pass through here.
if (v && typeof v.next === "function") {
return [...v];
}
return v;
}
/**
* Add a type to the type system.
*
* When registering a type, you can provide `read` and `write` methods.
*
* The `read` method will be passed a JS object value from the JSON
* packet and must return a native representation. The `write` method will
* be passed a native representation and should provide a JSONable value.
*
* These methods will both be passed a context. The context is the object
* performing or servicing the request - on the server side it will be
* an Actor, on the client side it will be a Front.
*
* @param typestring name
* Name to register
* @param object typeObject
* An object whose properties will be stored in the type, including
* the `read` and `write` methods.
* @param object options
* Can specify `thawed` to prevent the type from being frozen.
*
* @returns a type object that can be used in protocol definitions.
*/
types.addType = function(name, typeObject = {}, options = {}) {
if (registeredTypes.has(name)) {
throw Error("Type '" + name + "' already exists.");
}
const type = Object.assign(
{
toString() {
return "[protocol type:" + name + "]";
},
name: name,
primitive: !(typeObject.read || typeObject.write),
read: identityWrite,
write: identityWrite,
},
typeObject
);
registeredTypes.set(name, type);
return type;
};
/**
* Remove a type previously registered with the system.
* Primarily useful for types registered by addons.
*/
types.removeType = function(name) {
// This type may still be referenced by other types, make sure
// those references don't work.
const type = registeredTypes.get(name);
type.name = "DEFUNCT:" + name;
type.category = "defunct";
type.primitive = false;
type.read = type.write = function() {
throw new Error("Using defunct type: " + name);
};
registeredTypes.delete(name);
};
/**
* Add an array type to the type system.
*
* getType() will call this function if provided an "array:<type>"
* typestring.
*
* @param type subtype
* The subtype to be held by the array.
*/
types.addArrayType = function(subtype) {
subtype = types.getType(subtype);
const name = "array:" + subtype.name;
// Arrays of primitive types are primitive types themselves.
if (subtype.primitive) {
return types.addType(name);
}
return types.addType(name, {
category: "array",
read: (v, ctx) => {
if (v && typeof v.next === "function") {
v = [...v];
}
return v.map(i => subtype.read(i, ctx));
},
write: (v, ctx) => {
if (v && typeof v.next === "function") {
v = [...v];
}
return v.map(i => subtype.write(i, ctx));
},
});
};
/**
* Add a dict type to the type system. This allows you to serialize
* a JS object that contains non-primitive subtypes.
*
* Properties of the value that aren't included in the specializations
* will be serialized as primitive values.
*
* @param object specializations
* A dict of property names => type
*/
types.addDictType = function(name, specializations) {
const specTypes = {};
for (const prop in specializations) {
try {
specTypes[prop] = types.getType(specializations[prop]);
} catch (e) {
// Types may not be defined yet. Sometimes, we define the type *after* using it, but
// also, we have cyclic definitions on types. So lazily load them when they are not
// immediately available.
loader.lazyGetter(specTypes, prop, () => {
return types.getType(specializations[prop]);
});
}
}
return types.addType(name, {
category: "dict",
specializations,
read: (v, ctx) => {
const ret = {};
for (const prop in v) {
if (prop in specTypes) {
ret[prop] = specTypes[prop].read(v[prop], ctx);
} else {
ret[prop] = v[prop];
}
}
return ret;
},
write: (v, ctx) => {
const ret = {};
for (const prop in v) {
if (prop in specTypes) {
ret[prop] = specTypes[prop].write(v[prop], ctx);
} else {
ret[prop] = v[prop];
}
}
return ret;
},
});
};
/**
* Register an actor type with the type system.
*
* Types are marshalled differently when communicating server->client
* than they are when communicating client->server. The server needs
* to provide useful information to the client, so uses the actor's
* `form` method to get a json representation of the actor. When
* making a request from the client we only need the actor ID string.
*
* This function can be called before the associated actor has been
* constructed, but the read and write methods won't work until
* the associated addActorImpl or addActorFront methods have been
* called during actor/front construction.
*
* @param string name
* The typestring to register.
*/
types.addActorType = function(name) {
// We call addActorType from:
// FrontClassWithSpec when registering front synchronously,
// generateActorSpec when defining specs,
// specs modules to register actor type early to use them in other types
if (registeredTypes.has(name)) {
return registeredTypes.get(name);
}
const type = types.addType(name, {
_actor: true,
category: "actor",
read: (v, ctx, detail) => {
// If we're reading a request on the server side, just
// find the actor registered with this actorID.
if (ctx instanceof Actor) {
return ctx.conn.getActor(v);
}
// Reading a response on the client side, check for an
// existing front on the connection, and create the front
// if it isn't found.
const actorID = typeof v === "string" ? v : v.actor;
let front = ctx.conn.getActor(actorID);
if (!front) {
// If front isn't instantiated yet, create one.
// Try lazy loading front if not already loaded.
// The front module will synchronously call `FrontClassWithSpec` and
// augment `type` with the `frontClass` attribute.
if (!type.frontClass) {
lazyLoadFront(name);
}
// Use intermediate Class variable to please eslint requiring
// a capital letter for all constructors.
const Class = type.frontClass;
front = new Class(ctx.conn);
front.actorID = actorID;
ctx.marshallPool().manage(front);
}
// When the type `${name}#actorid` is used, `v` is a string refering to the
// actor ID. We only set the actorID just before and so do not need anything else.
if (detail != "actorid") {
v = identityWrite(v);
front.form(v, ctx);
}
return front;
},
write: (v, ctx, detail) => {
// If returning a response from the server side, make sure
// the actor is added to a parent object and return its form.
if (v instanceof Actor) {
if (!v.actorID) {
ctx.marshallPool().manage(v);
}
if (detail == "actorid") {
return v.actorID;
}
return identityWrite(v.form(detail));
}
// Writing a request from the client side, just send the actor id.
return v.actorID;
},
});
return type;
};
types.addNullableType = function(subtype) {
subtype = types.getType(subtype);
return types.addType("nullable:" + subtype.name, {
category: "nullable",
read: (value, ctx) => {
if (value == null) {
return value;
}
return subtype.read(value, ctx);
},
write: (value, ctx) => {
if (value == null) {
return value;
}
return subtype.write(value, ctx);
},
});
};
/**
* Register an actor detail type. This is just like an actor type, but
* will pass a detail hint to the actor's form method during serialization/
* deserialization.
*
* This is called by getType() when passed an 'actorType#detail' string.
*
* @param string name
* The typestring to register this type as.
* @param type actorType
* The actor type you'll be detailing.
* @param string detail
* The detail to pass.
*/
types.addActorDetail = function(name, actorType, detail) {
actorType = types.getType(actorType);
if (!actorType._actor) {
throw Error(
`Details only apply to actor types, tried to add detail '${detail}' ` +
`to ${actorType.name}`
);
}
return types.addType(name, {
_actor: true,
category: "detail",
read: (v, ctx) => actorType.read(v, ctx, detail),
write: (v, ctx) => actorType.write(v, ctx, detail),
});
};
/**
* Register an actor lifetime. This lets the type system find a parent
* actor that differs from the actor fulfilling the request.
*
* @param string name
* The lifetime name to use in typestrings.
* @param string prop
* The property of the actor that holds the parent that should be used.
*/
types.addLifetime = function(name, prop) {
if (registeredLifetimes.has(name)) {
throw Error("Lifetime '" + name + "' already registered.");
}
registeredLifetimes.set(name, prop);
};
/**
* Remove a previously-registered lifetime. Useful for lifetimes registered
* in addons.
*/
types.removeLifetime = function(name) {
registeredLifetimes.delete(name);
};
/**
* Register a lifetime type. This creates an actor type tied to the given
* lifetime.
*
* This is called by getType() when passed a '<lifetimeType>:<actorType>'
* typestring.
*
* @param string lifetime
* A lifetime string previously regisered with addLifetime()
* @param type subtype
* An actor type
*/
types.addLifetimeType = function(lifetime, subtype) {
subtype = types.getType(subtype);
if (!subtype._actor) {
throw Error(
`Lifetimes only apply to actor types, tried to apply ` +
`lifetime '${lifetime}' to ${subtype.name}`
);
}
const prop = registeredLifetimes.get(lifetime);
return types.addType(lifetime + ":" + subtype.name, {
category: "lifetime",
read: (value, ctx) => subtype.read(value, ctx[prop]),
write: (value, ctx) => subtype.write(value, ctx[prop]),
});
};
// Add a few named primitive types.
types.Primitive = types.addType("primitive");
types.String = types.addType("string");
types.Number = types.addType("number");
types.Boolean = types.addType("boolean");
types.JSON = types.addType("json");
exports.registerFront = function(cls) {
const { typeName } = cls.prototype;
if (!registeredTypes.has(typeName)) {
types.addActorType(typeName);
}
registeredTypes.get(typeName).frontClass = cls;
};
/**
* Instantiate a global (preference, device) or target-scoped (webconsole, inspector)
* front of the given type by picking its actor ID out of either the target or root
* front's form.
*
* @param DebuggerClient client
* The DebuggerClient instance to use.
* @param string typeName
* The type name of the front to instantiate. This is defined in its specifiation.
* @param json form
* If we want to instantiate a global actor's front, this is the root front's form,
* otherwise we are instantiating a target-scoped front from the target front's form.
*/
function getFront(client, typeName, form) {
const type = types.getType(typeName);
if (!type) {
throw new Error(`No spec for front type '${typeName}'.`);
}
if (!type.frontClass) {
lazyLoadFront(typeName);
}
// Use intermediate Class variable to please eslint requiring
// a capital letter for all constructors.
const Class = type.frontClass;
const instance = new Class(client);
const { formAttributeName } = instance;
if (!formAttributeName) {
throw new Error(`Can't find the form attribute name for ${typeName}`);
}
// Retrive the actor ID from root or target actor's form
instance.actorID = form[formAttributeName];
if (!instance.actorID) {
throw new Error(
`Can't find the actor ID for ${typeName} from root or target` +
` actor's form.`
);
}
// Historically, all global and target scoped front were the first protocol.js in the
// hierarchy of fronts. So that they have to self-own themself. But now, Root and Target
// are fronts and should own them. The only issue here is that we should manage the
// front *before* calling initialize which is going to try managing child fronts.
instance.manage(instance);
if (typeof instance.initialize == "function") {
return instance.initialize().then(() => instance);
}
return instance;
}
exports.getFront = getFront;

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"use strict";
function describeTemplate(template) {
return JSON.parse(
JSON.stringify(template, (key, value) => {
if (value.describe) {
return value.describe();
}
return value;
})
);
}
exports.describeTemplate = describeTemplate;
/**
* Find Placeholders in the template and save them along with their
* paths.
*/
function findPlaceholders(template, constructor, path = [], placeholders = []) {
if (!template || typeof template != "object") {
return placeholders;
}
if (template instanceof constructor) {
placeholders.push({ placeholder: template, path: [...path] });
return placeholders;
}
for (const name in template) {
path.push(name);
findPlaceholders(template[name], constructor, path, placeholders);
path.pop();
}
return placeholders;
}
exports.findPlaceholders = findPlaceholders;
/**
* Get the value at a given path, or undefined if not found.
*/
function getPath(obj, path) {
for (const name of path) {
if (!(name in obj)) {
return undefined;
}
obj = obj[name];
}
return obj;
}
exports.getPath = getPath;
/**
* Tags a prtotype method as an actor method implementation.
*
* @param function fn
* The implementation function, will be returned.
* @param spec
* The method specification, with the following (optional) properties:
* request (object): a request template.
* response (object): a response template.
* oneway (bool): 'true' if no response should be sent.
*/
exports.method = function(fn, spec = {}) {
fn._methodSpec = Object.freeze(spec);
if (spec.request) {
Object.freeze(spec.request);
}
if (spec.response) {
Object.freeze(spec.response);
}
return fn;
};