Add m-esr52 at 52.6.0

1 files changed, 1517 insertions, 0 deletions

diff --git a/devtools/shared/protocol.js b/devtools/shared/protocol.js
new file mode 100644
index 000000000..4035d5016
--- /dev/null
+++ b/devtools/shared/protocol.js
@@ -0,0 +1,1517 @@
+/* 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";
+
+var promise = require("promise");
+var defer = require("devtools/shared/defer");
+var {Class} = require("sdk/core/heritage");
+var {EventTarget} = require("sdk/event/target");
+var events = require("sdk/event/core");
+var object = require("sdk/util/object");
+var {getStack, callFunctionWithAsyncStack} = require("devtools/shared/platform/stack");
+
+exports.emit = events.emit;
+
+/**
+ * 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();
+
+/**
+ * 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;
+
+  // New type, see if it's a collection/lifetime type:
+  let sep = type.indexOf(":");
+  if (sep >= 0) {
+    let collection = type.substring(0, sep);
+    let 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
+  let pieces = type.split("#", 2);
+  if (pieces.length > 1) {
+    return types.addActorDetail(type, pieces[0], pieces[1]);
+  }
+
+  // Might be a lazily-loaded type
+  if (type === "longstring") {
+    require("devtools/shared/specs/string");
+    return registeredTypes.get("longstring");
+  }
+
+  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) === "object" && Symbol.iterator in v) {
+    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.");
+  }
+
+  let type = object.merge({
+    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.
+  let 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);
+
+  let 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) => [...v].map(i => subtype.read(i, ctx)),
+    write: (v, ctx) => [...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) {
+  return types.addType(name, {
+    category: "dict",
+    specializations: specializations,
+    read: (v, ctx) => {
+      let ret = {};
+      for (let prop in v) {
+        if (prop in specializations) {
+          ret[prop] = types.getType(specializations[prop]).read(v[prop], ctx);
+        } else {
+          ret[prop] = v[prop];
+        }
+      }
+      return ret;
+    },
+
+    write: (v, ctx) => {
+      let ret = {};
+      for (let prop in v) {
+        if (prop in specializations) {
+          ret[prop] = types.getType(specializations[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) {
+  let 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.
+      let actorID = typeof (v) === "string" ? v : v.actor;
+      let front = ctx.conn.getActor(actorID);
+      if (!front) {
+        front = new type.frontClass(ctx.conn);
+        front.actorID = actorID;
+        ctx.marshallPool().manage(front);
+      }
+
+      v = type.formType(detail).read(v, front, detail);
+      front.form(v, detail, 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);
+        }
+        return type.formType(detail).write(v.form(detail), ctx, detail);
+      }
+
+      // Writing a request from the client side, just send the actor id.
+      return v.actorID;
+    },
+    formType: (detail) => {
+      if (!("formType" in type.actorSpec)) {
+        return types.Primitive;
+      }
+
+      let formAttr = "formType";
+      if (detail) {
+        formAttr += "#" + detail;
+      }
+
+      if (!(formAttr in type.actorSpec)) {
+        throw new Error("No type defined for " + formAttr);
+      }
+
+      return type.actorSpec[formAttr];
+    }
+  });
+  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 + "\n");
+  }
+  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);
+  }
+  let 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");
+
+/**
+ * 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 = Class({
+  initialize: function (index, type) {
+    this.index = index;
+    this.type = types.getType(type);
+  },
+
+  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,
+    };
+  }
+});
+exports.Arg = Arg;
+
+/**
+ * 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 = Class({
+  extends: Arg,
+  initialize: function (index, type) {
+    Arg.prototype.initialize.call(this, index, type);
+  },
+
+  write: function (arg, ctx, name) {
+    // Ignore if arg is undefined or null; allow other falsy values
+    if (arg == undefined || arg[name] == undefined) {
+      return undefined;
+    }
+    let 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,
+    };
+  }
+});
+
+exports.Option = Option;
+
+/**
+ * Placeholder for return values in a response template.
+ *
+ * @param type type
+ *    The return value should be marshalled as this type.
+ */
+var RetVal = Class({
+  initialize: function (type) {
+    this.type = types.getType(type);
+  },
+
+  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
+    };
+  }
+});
+
+exports.RetVal = RetVal;
+
+/* Template handling functions */
+
+/**
+ * Get the value at a given path, or undefined if not found.
+ */
+function getPath(obj, path) {
+  for (let name of path) {
+    if (!(name in obj)) {
+      return undefined;
+    }
+    obj = obj[name];
+  }
+  return obj;
+}
+
+/**
+ * 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 (let name in template) {
+    path.push(name);
+    findPlaceholders(template[name], constructor, path, placeholders);
+    path.pop();
+  }
+
+  return placeholders;
+}
+
+
+function describeTemplate(template) {
+  return JSON.parse(JSON.stringify(template, (key, value) => {
+    if (value.describe) {
+      return value.describe();
+    }
+    return value;
+  }));
+}
+
+/**
+ * Manages a request template.
+ *
+ * @param object template
+ *    The request template.
+ * @construcor
+ */
+var Request = Class({
+  initialize: function (template = {}) {
+    this.type = template.type;
+    this.template = template;
+    this.args = findPlaceholders(template, Arg);
+  },
+
+  /**
+   * 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) {
+    let str = JSON.stringify(this.template, (key, value) => {
+      if (value instanceof Arg) {
+        return value.write(value.index in fnArgs ? fnArgs[value.index] : undefined,
+                           ctx, key);
+      }
+      return value;
+    });
+    return JSON.parse(str);
+  },
+
+  /**
+   * 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) {
+    let fnArgs = [];
+    for (let templateArg of this.args) {
+      let arg = templateArg.placeholder;
+      let path = templateArg.path;
+      let name = path[path.length - 1];
+      arg.read(getPath(packet, path), ctx, fnArgs, name);
+    }
+    return fnArgs;
+  },
+
+  describe: function () { return describeTemplate(this.template); }
+});
+
+/**
+ * Manages a response template.
+ *
+ * @param object template
+ *    The response template.
+ * @construcor
+ */
+var Response = Class({
+  initialize: function (template = {}) {
+    this.template = template;
+    let placeholders = findPlaceholders(template, RetVal);
+    if (placeholders.length > 1) {
+      throw Error("More than one RetVal specified in response");
+    }
+    let placeholder = placeholders.shift();
+    if (placeholder) {
+      this.retVal = placeholder.placeholder;
+      this.path = placeholder.path;
+    }
+  },
+
+  /**
+   * 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) {
+    return JSON.parse(JSON.stringify(this.template, function (key, value) {
+      if (value instanceof RetVal) {
+        return value.write(ret, ctx);
+      }
+      return value;
+    }));
+  },
+
+  /**
+   * 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;
+    }
+    let v = getPath(packet, this.path);
+    return this.retVal.read(v, ctx);
+  },
+
+  describe: function () { return describeTemplate(this.template); }
+});
+
+/**
+ * Actor and Front implementations
+ */
+
+/**
+ * A protocol object that can manage the lifetime of other protocol
+ * objects.
+ */
+var Pool = Class({
+  extends: EventTarget,
+
+  /**
+   * 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
+   */
+  initialize: function (conn) {
+    if (conn) {
+      this.conn = conn;
+    }
+  },
+
+  /**
+   * Return the parent pool for this client.
+   */
+  parent: function () { return this.conn.poolFor(this.actorID); },
+
+  /**
+   * Override this if you want actors returned by this actor
+   * to belong to a different actor by default.
+   */
+  marshallPool: function () { 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.
+   */
+  __poolMap: null,
+  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: function (actor) {
+    if (!actor.actorID) {
+      actor.actorID = this.conn.allocID(actor.actorPrefix || actor.typeName);
+    }
+
+    this._poolMap.set(actor.actorID, actor);
+    return actor;
+  },
+
+  /**
+   * Remove an actor as a child of this pool.
+   */
+  unmanage: function (actor) {
+    this.__poolMap && this.__poolMap.delete(actor.actorID);
+  },
+
+  // true if the given actor ID exists in the pool.
+  has: function (actorID) {
+    return this.__poolMap && this._poolMap.has(actorID);
+  },
+
+  // The actor for a given actor id stored in this pool
+  actor: function (actorID) {
+    return this.__poolMap ? this._poolMap.get(actorID) : null;
+  },
+
+  // Same as actor, should update debugger connection to use 'actor'
+  // and then remove this.
+  get: function (actorID) {
+    return this.__poolMap ? this._poolMap.get(actorID) : null;
+  },
+
+  // True if this pool has no children.
+  isEmpty: function () {
+    return !this.__poolMap || this._poolMap.size == 0;
+  },
+
+  /**
+   * Destroy this item, removing it from a parent if it has one,
+   * and destroying all children if necessary.
+   */
+  destroy: function () {
+    let parent = this.parent();
+    if (parent) {
+      parent.unmanage(this);
+    }
+    if (!this.__poolMap) {
+      return;
+    }
+    for (let actor of this.__poolMap.values()) {
+      // Self-owned actors are ok, but don't need destroying twice.
+      if (actor === this) {
+        continue;
+      }
+      let 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: function () {
+    this.destroy();
+  }
+});
+exports.Pool = Pool;
+
+/**
+ * An actor in the actor tree.
+ */
+var Actor = Class({
+  extends: Pool,
+
+  // Will contain the actor's ID
+  actorID: null,
+
+  /**
+   * Initialize an actor.
+   *
+   * @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
+   */
+  initialize: function (conn) {
+    Pool.prototype.initialize.call(this, conn);
+
+    // Forward events to the connection.
+    if (this._actorSpec && this._actorSpec.events) {
+      for (let key of this._actorSpec.events.keys()) {
+        let name = key;
+        let sendEvent = this._sendEvent.bind(this, name);
+        this.on(name, (...args) => {
+          sendEvent.apply(null, args);
+        });
+      }
+    }
+  },
+
+  toString: function () { return "[Actor " + this.typeName + "/" + this.actorID + "]"; },
+
+  _sendEvent: function (name, ...args) {
+    if (!this._actorSpec.events.has(name)) {
+      // It's ok to emit events that don't go over the wire.
+      return;
+    }
+    let request = this._actorSpec.events.get(name);
+    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: function () {
+    Pool.prototype.destroy.call(this);
+    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: function (hint) {
+    return { actor: this.actorID };
+  },
+
+  writeError: function (error) {
+    console.error(error);
+    if (error.stack) {
+      dump(error.stack);
+    }
+    this.conn.send({
+      from: this.actorID,
+      error: error.error || "unknownError",
+      message: error.message
+    });
+  },
+
+  _queueResponse: function (create) {
+    let pending = this._pendingResponse || promise.resolve(null);
+    let response = create(pending);
+    this._pendingResponse = response;
+  }
+});
+exports.Actor = Actor;
+
+/**
+ * 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;
+};
+
+/**
+ * Generates an actor specification from an actor description.
+ */
+var generateActorSpec = function (actorDesc) {
+  let actorSpec = {
+    typeName: actorDesc.typeName,
+    methods: []
+  };
+
+  // Find method and form specifications attached to properties.
+  for (let name of Object.getOwnPropertyNames(actorDesc)) {
+    let desc = Object.getOwnPropertyDescriptor(actorDesc, name);
+    if (!desc.value) {
+      continue;
+    }
+
+    if (name.startsWith("formType")) {
+      if (typeof (desc.value) === "string") {
+        actorSpec[name] = types.getType(desc.value);
+      } else if (desc.value.name && registeredTypes.has(desc.value.name)) {
+        actorSpec[name] = desc.value;
+      } else {
+        // Shorthand for a newly-registered DictType.
+        actorSpec[name] = types.addDictType(actorDesc.typeName + "__" + name, desc.value);
+      }
+    }
+
+    if (desc.value._methodSpec) {
+      let methodSpec = desc.value._methodSpec;
+      let spec = {};
+      spec.name = methodSpec.name || name;
+      spec.request = Request(object.merge({type: spec.name}, methodSpec.request || undefined));
+      spec.response = Response(methodSpec.response || undefined);
+      spec.release = methodSpec.release;
+      spec.oneway = methodSpec.oneway;
+
+      actorSpec.methods.push(spec);
+    }
+  }
+
+  // Find additional method specifications
+  if (actorDesc.methods) {
+    for (let name in actorDesc.methods) {
+      let methodSpec = actorDesc.methods[name];
+      let spec = {};
+
+      spec.name = methodSpec.name || name;
+      spec.request = Request(object.merge({type: spec.name}, methodSpec.request || undefined));
+      spec.response = 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 (let name in actorDesc.events) {
+      let eventRequest = actorDesc.events[name];
+      Object.freeze(eventRequest);
+      actorSpec.events.set(name, Request(object.merge({type: name}, eventRequest)));
+    }
+  }
+
+  if (!registeredTypes.has(actorSpec.typeName)) {
+    types.addActorType(actorSpec.typeName);
+  }
+  registeredTypes.get(actorSpec.typeName).actorSpec = actorSpec;
+
+  return actorSpec;
+};
+exports.generateActorSpec = generateActorSpec;
+
+/**
+ * Generates request handlers as described by the given actor specification on
+ * the given actor prototype. Returns the actor prototype.
+ */
+var generateRequestHandlers = function (actorSpec, actorProto) {
+  if (actorProto._actorSpec) {
+    throw new Error("actorProto called twice on the same actor prototype!");
+  }
+
+  actorProto.typeName = actorSpec.typeName;
+
+  // Generate request handlers for each method definition
+  actorProto.requestTypes = Object.create(null);
+  actorSpec.methods.forEach(spec => {
+    let 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;
+        }
+
+        let ret = this[spec.name].apply(this, args);
+
+        let sendReturn = (ret) => {
+          if (spec.oneway) {
+            // No need to send a response.
+            return;
+          }
+
+          let response;
+          try {
+            response = spec.response.write(ret, 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);
+              return;
+            }
+          }
+
+          conn.send(response);
+        };
+
+        this._queueResponse(p => {
+          return p
+            .then(() => ret)
+            .then(sendReturn)
+            .then(null, this.writeError.bind(this));
+        });
+      } catch (e) {
+        this._queueResponse(p => {
+          return p.then(() => this.writeError(e));
+        });
+      }
+    };
+
+    actorProto.requestTypes[spec.request.type] = handler;
+  });
+
+  actorProto._actorSpec = actorSpec;
+
+  return actorProto;
+};
+
+/**
+ * THIS METHOD IS DEPRECATED, AND PRESERVED ONLY FOR ADD-ONS. IT SHOULD NOT BE
+ * USED INSIDE THE TREE.
+ *
+ * Create an actor class for the given actor prototype.
+ *
+ * @param object actorProto
+ *    The actor prototype.  Must have a 'typeName' property,
+ *    should have method definitions, can have event definitions.
+ */
+exports.ActorClass = function (actorProto) {
+  return ActorClassWithSpec(generateActorSpec(actorProto), actorProto);
+};
+
+/**
+ * THIS METHOD IS DEPRECATED, AND PRESERVED ONLY FOR ADD-ONS. IT SHOULD NOT BE
+ * USED INSIDE THE TREE.
+ *
+ * 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.");
+  }
+
+  actorProto.extends = Actor;
+  let cls = Class(generateRequestHandlers(actorSpec, actorProto));
+
+  return cls;
+};
+exports.ActorClassWithSpec = ActorClassWithSpec;
+
+/**
+ * Base class for client-side actor fronts.
+ */
+var Front = Class({
+  extends: Pool,
+
+  actorID: null,
+
+  /**
+   * The 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.
+   * @param optional form
+   *   The json form provided by the server.
+   * @constructor
+   */
+  initialize: function (conn = null, form = null, detail = null, context = null) {
+    Pool.prototype.initialize.call(this, conn);
+    this._requests = [];
+
+    // protocol.js no longer uses this data in the constructor, only external
+    // uses do.  External usage of manually-constructed fronts will be
+    // drastically reduced if we convert the root and tab actors to
+    // protocol.js, in which case this can probably go away.
+    if (form) {
+      this.actorID = form.actor;
+      form = types.getType(this.typeName).formType(detail).read(form, this, detail);
+      this.form(form, detail, context);
+    }
+  },
+
+  destroy: function () {
+    // Reject all outstanding requests, they won't make sense after
+    // the front is destroyed.
+    while (this._requests && this._requests.length > 0) {
+      let { deferred, to, type, stack } = this._requests.shift();
+      let msg = "Connection closed, pending request to " + to +
+                ", type " + type + " failed" +
+                "\n\nRequest stack:\n" + stack.formattedStack;
+      deferred.reject(new Error(msg));
+    }
+    Pool.prototype.destroy.call(this);
+    this.actorID = null;
+  },
+
+  manage: function (front) {
+    if (!front.actorID) {
+      throw new Error("Can't manage front without an actor ID.\n" +
+                      "Ensure server supports " + front.typeName + ".");
+    }
+    return Pool.prototype.manage.call(this, front);
+  },
+
+  /**
+   * @returns a promise that will resolve to the actorID this front
+   * represents.
+   */
+  actor: function () { return promise.resolve(this.actorID); },
+
+  toString: function () { return "[Front for " + this.typeName + "/" + this.actorID + "]"; },
+
+  /**
+   * Update the actor from its representation.
+   * Subclasses should override this.
+   */
+  form: function (form) {},
+
+  /**
+   * Send a packet on the connection.
+   */
+  send: function (packet) {
+    if (packet.to) {
+      this.conn._transport.send(packet);
+    } else {
+      this.actor().then(actorID => {
+        packet.to = actorID;
+        this.conn._transport.send(packet);
+      }).then(null, e => console.error(e));
+    }
+  },
+
+  /**
+   * Send a two-way request on the connection.
+   */
+  request: function (packet) {
+    let deferred = defer();
+    // Save packet basics for debugging
+    let { 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: function (packet) {
+    // Pick off event packets
+    let type = packet.type || undefined;
+    if (this._clientSpec.events && this._clientSpec.events.has(type)) {
+      let 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;
+      }
+      if (event.pre) {
+        let results = event.pre.map(pre => pre.apply(this, args));
+
+        // Check to see if any of the preEvents returned a promise -- if so,
+        // wait for their resolution before emitting. Otherwise, emit synchronously.
+        if (results.some(result => result && typeof result.then === "function")) {
+          promise.all(results).then(() => events.emit.apply(null, [this, event.name].concat(args)));
+          return;
+        }
+      }
+
+      events.emit.apply(null, [this, event.name].concat(args));
+      return;
+    }
+
+    // Remaining packets must be responses.
+    if (this._requests.length === 0) {
+      let msg = "Unexpected packet " + this.actorID + ", " + JSON.stringify(packet);
+      let err = Error(msg);
+      console.error(err);
+      throw err;
+    }
+
+    let { 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");
+  }
+});
+exports.Front = Front;
+
+/**
+ * A method tagged with preEvent will be called after recieving a packet
+ * for that event, and before the front emits the event.
+ */
+exports.preEvent = function (eventName, fn) {
+  fn._preEvent = eventName;
+  return fn;
+};
+
+/**
+ * Mark a method as a custom front implementation, replacing the generated
+ * front method.
+ *
+ * @param function fn
+ *    The front implementation, will be returned.
+ * @param object options
+ *    Options object:
+ *      impl (string): If provided, the generated front method will be
+ *        stored as this property on the prototype.
+ */
+exports.custom = function (fn, options = {}) {
+  fn._customFront = options;
+  return fn;
+};
+
+function prototypeOf(obj) {
+  return typeof (obj) === "function" ? obj.prototype : obj;
+}
+
+/**
+ * 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.
+  let methods = actorSpec.methods;
+  methods.forEach(spec => {
+    let name = spec.name;
+
+    // If there's already a property by this name in the front, it must
+    // be a custom front method.
+    if (name in frontProto) {
+      let custom = frontProto[spec.name]._customFront;
+      if (custom === undefined) {
+        throw Error("Existing method for " + spec.name + " not marked customFront while processing " + actorType.typeName + ".");
+      }
+      // If the user doesn't need the impl don't generate it.
+      if (!custom.impl) {
+        return;
+      }
+      name = custom.impl;
+    }
+
+    frontProto[name] = function (...args) {
+      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);
+          throw ex;
+        }
+        return ret;
+      });
+    };
+
+    // Release methods should call the destroy function on return.
+    if (spec.release) {
+      let fn = frontProto[name];
+      frontProto[name] = function (...args) {
+        return fn.apply(this, args).then(result => {
+          this.destroy();
+          return result;
+        });
+      };
+    }
+  });
+
+
+  // Process event specifications
+  frontProto._clientSpec = {};
+
+  let events = actorSpec.events;
+  if (events) {
+    // This actor has events, scan the prototype for preEvent handlers...
+    let preHandlers = new Map();
+    for (let name of Object.getOwnPropertyNames(frontProto)) {
+      let desc = Object.getOwnPropertyDescriptor(frontProto, name);
+      if (!desc.value) {
+        continue;
+      }
+      if (desc.value._preEvent) {
+        let preEvent = desc.value._preEvent;
+        if (!events.has(preEvent)) {
+          throw Error("preEvent for event that doesn't exist: " + preEvent);
+        }
+        let handlers = preHandlers.get(preEvent);
+        if (!handlers) {
+          handlers = [];
+          preHandlers.set(preEvent, handlers);
+        }
+        handlers.push(desc.value);
+      }
+    }
+
+    frontProto._clientSpec.events = new Map();
+
+    for (let [name, request] of events) {
+      frontProto._clientSpec.events.set(request.type, {
+        name: name,
+        request: request,
+        pre: preHandlers.get(name)
+      });
+    }
+  }
+
+  frontProto._actorSpec = actorSpec;
+
+  return frontProto;
+};
+
+/**
+ * Create a front class for the given actor class and front prototype.
+ *
+ * @param ActorClass actorType
+ *    The actor class you're creating a front for.
+ * @param object frontProto
+ *    The front prototype.  Must have a 'typeName' property,
+ *    should have method definitions, can have event definitions.
+ */
+exports.FrontClass = function (actorType, frontProto) {
+  return FrontClassWithSpec(prototypeOf(actorType)._actorSpec, 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, frontProto) {
+  frontProto.extends = Front;
+  let cls = Class(generateRequestMethods(actorSpec, frontProto));
+
+  if (!registeredTypes.has(actorSpec.typeName)) {
+    types.addActorType(actorSpec.typeName);
+  }
+  registeredTypes.get(actorSpec.typeName).frontClass = cls;
+
+  return cls;
+};
+exports.FrontClassWithSpec = FrontClassWithSpec;
+
+exports.dumpActorSpec = function (type) {
+  let actorSpec = type.actorSpec;
+  let ret = {
+    category: "actor",
+    typeName: type.name,
+    methods: [],
+    events: {}
+  };
+
+  for (let method of actorSpec.methods) {
+    ret.methods.push({
+      name: method.name,
+      release: method.release || undefined,
+      oneway: method.oneway || undefined,
+      request: method.request.describe(),
+      response: method.response.describe()
+    });
+  }
+
+  if (actorSpec.events) {
+    for (let [name, request] of actorSpec.events) {
+      ret.events[name] = request.describe();
+    }
+  }
+
+
+  JSON.stringify(ret);
+
+  return ret;
+};
+
+exports.dumpProtocolSpec = function () {
+  let ret = {
+    types: {},
+  };
+
+  for (let [name, type] of registeredTypes) {
+    // Force lazy instantiation if needed.
+    type = types.getType(name);
+    let category = type.category || undefined;
+    if (category === "dict") {
+      ret.types[name] = {
+        category: "dict",
+        typeName: name,
+        specializations: type.specializations
+      };
+    } else if (category === "actor") {
+      ret.types[name] = exports.dumpActorSpec(type);
+    }
+  }
+
+  return ret;
+};