Quelle thread.js Sprache: JAVA

/* 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";

// protocol.js uses objects as exceptions in order to define
// error packets.
/* eslint-disable no-throw-literal */

const { Actor } = require("resource://devtools/shared/protocol/Actor.js");
const { Pool } = require("resource://devtools/shared/protocol/Pool.js");
const { threadSpec } = require("resource://devtools/shared/specs/thread.js");

const {
  createValueGrip,
} = require("resource://devtools/server/actors/object/utils.js");
const {
  ObjectActorPool,
} = require("resource://devtools/server/actors/object/ObjectActorPool.js");
const DevToolsUtils = require("resource://devtools/shared/DevToolsUtils.js");
const Debugger = require("Debugger");
const { assert, dumpn, reportException } = DevToolsUtils;
const {
  getAvailableEventBreakpoints,
  eventBreakpointForNotification,
  eventsRequireNotifications,
  firstStatementBreakpointId,
  makeEventBreakpointMessage,
} = require("resource://devtools/server/actors/utils/event-breakpoints.js");
const {
  WatchpointMap,
} = require("resource://devtools/server/actors/utils/watchpoint-map.js");

const Targets = require("devtools/server/actors/targets/index");

loader.lazyRequireGetter(
  this,
  "logEvent",
  "resource://devtools/server/actors/utils/logEvent.js",
  true
);
loader.lazyRequireGetter(
  this,
  "EnvironmentActor",
  "resource://devtools/server/actors/environment.js",
  true
);
loader.lazyRequireGetter(
  this,
  "BreakpointActorMap",
  "resource://devtools/server/actors/utils/breakpoint-actor-map.js",
  true
);
loader.lazyRequireGetter(
  this,
  "EventLoop",
  "resource://devtools/server/actors/utils/event-loop.js",
  true
);
loader.lazyRequireGetter(
  this,
  ["FrameActor", "getSavedFrameParent", "isValidSavedFrame"],
  "resource://devtools/server/actors/frame.js",
  true
);
loader.lazyRequireGetter(
  this,
  "HighlighterEnvironment",
  "resource://devtools/server/actors/highlighters.js",
  true
);
loader.lazyRequireGetter(
  this,
  "PausedDebuggerOverlay",
  "resource://devtools/server/actors/highlighters/paused-debugger.js",
  true
);

const PROMISE_REACTIONS = new WeakMap();
function cacheReactionsForFrame(frame) {
  if (frame.asyncPromise) {
    const reactions = frame.asyncPromise.getPromiseReactions();
    const existingReactions = PROMISE_REACTIONS.get(frame.asyncPromise);
    if (
      reactions.length &&
      (!existingReactions || reactions.length > existingReactions.length)
    ) {
      PROMISE_REACTIONS.set(frame.asyncPromise, reactions);
    }
  }
}

function createStepForReactionTracking(onStep) {
  return function () {
    cacheReactionsForFrame(this);
    return onStep ? onStep.apply(this, arguments) : undefined;
  };
}

const getAsyncParentFrame = frame => {
  if (!frame.asyncPromise) {
    return null;
  }

  // We support returning Frame actors for frames that are suspended
  // at an 'await', and here we want to walk upward to look for the first
  // frame that will be resumed when the current frame's promise resolves.
  let reactions =
    PROMISE_REACTIONS.get(frame.asyncPromise) ||
    frame.asyncPromise.getPromiseReactions();

  while (true) {
    // We loop here because we may have code like:
    //
    //   async function inner(){ debugger; }
    //
    //   async function outer() {
    //     await Promise.resolve().then(() => inner());
    //   }
    //
    // where we can see that when `inner` resolves, we will resume from
    // `outer`, even though there is a layer of promises between, and
    // that layer could be any number of promises deep.
    if (!(reactions[0] instanceof Debugger.Object)) {
      break;
    }

    reactions = reactions[0].getPromiseReactions();
  }

  if (reactions[0] instanceof Debugger.Frame) {
    return reactions[0];
  }
  return null;
};
const RESTARTED_FRAMES = new WeakSet();

// Thread actor possible states:
const STATES = {
  //  Before ThreadActor.attach is called:
  DETACHED: "detached",
  //  After the actor is destroyed:
  EXITED: "exited",

  // States possible in between DETACHED AND EXITED:
  // Default state, when the thread isn't paused,
  RUNNING: "running",
  // When paused on any type of breakpoint, or, when the client requested an interrupt.
  PAUSED: "paused",
};
exports.STATES = STATES;

// Possible values for the `why.type` attribute in "paused" event
const PAUSE_REASONS = {
  ALREADY_PAUSED: "alreadyPaused",
  INTERRUPTED: "interrupted", // Associated with why.onNext attribute
  MUTATION_BREAKPOINT: "mutationBreakpoint", // Associated with why.mutationType and why.message attributes
  DEBUGGER_STATEMENT: "debuggerStatement",
  EXCEPTION: "exception",
  XHR: "XHR",
  EVENT_BREAKPOINT: "eventBreakpoint",
  RESUME_LIMIT: "resumeLimit",
};
exports.PAUSE_REASONS = PAUSE_REASONS;

class ThreadActor extends Actor {
  /**
   * Creates a ThreadActor.
   *
   * ThreadActors manage execution/inspection of debuggees.
   *
   * @param {TargetActor} targetActor
   *        This `ThreadActor`'s parent actor. i.e. one of the many Target actors.
   */
  constructor(targetActor) {
    super(targetActor.conn, threadSpec);

    // This attribute is used by various other actors to find the target actor
    this.targetActor = targetActor;

    this._state = STATES.DETACHED;
    this._options = {
      skipBreakpoints: false,
    };
    this._gripDepth = 0;
    this._targetActorClosed = false;
    this._observingNetwork = false;
    this._shouldShowPauseOverlay = true;
    this._frameActors = [];
    this._xhrBreakpoints = [];

    this._dbg = null;
    this._threadLifetimePool = null;
    this._activeEventPause = null;
    this._pauseOverlay = null;
    this._priorPause = null;

    this._activeEventBreakpoints = new Set();
    this._frameActorMap = new WeakMap();
    this._debuggerSourcesSeen = new WeakSet();

    // A Set of URLs string to watch for when new sources are found by
    // the debugger instance.
    this._onLoadBreakpointURLs = new Set();

    // A WeakMap from Debugger.Frame to an exception value which will be ignored
    // when deciding to pause if the value is thrown by the frame. When we are
    // pausing on exceptions then we only want to pause when the youngest frame
    // throws a particular exception, instead of for all older frames as well.
    this._handledFrameExceptions = new WeakMap();

    this._watchpointsMap = new WatchpointMap(this);

    this.breakpointActorMap = new BreakpointActorMap(this);

    this._nestedEventLoop = new EventLoop({
      thread: this,
    });

    this.onNewSourceEvent = this.onNewSourceEvent.bind(this);

    this.createCompletionGrip = this.createCompletionGrip.bind(this);
    this.onDebuggerStatement = this.onDebuggerStatement.bind(this);
    this.onNewScript = this.onNewScript.bind(this);
    this._onOpeningRequest = this._onOpeningRequest.bind(this);
    this._onNewDebuggee = this._onNewDebuggee.bind(this);
    this._onExceptionUnwind = this._onExceptionUnwind.bind(this);
    this._eventBreakpointListener = this._eventBreakpointListener.bind(this);
    this._onWindowReady = this._onWindowReady.bind(this);
    this._onWillNavigate = this._onWillNavigate.bind(this);
    this._onNavigate = this._onNavigate.bind(this);

    this.targetActor.on("window-ready", this._onWindowReady);
    this.targetActor.on("will-navigate", this._onWillNavigate);
    this.targetActor.on("navigate", this._onNavigate);

    this._firstStatementBreakpoint = null;
    this._debuggerNotificationObserver = new DebuggerNotificationObserver();
  }

  // Used by the ObjectActor to keep track of the depth of grip() calls.
  _gripDepth = null;

  get dbg() {
    if (!this._dbg) {
      this._dbg = this.targetActor.dbg;
      // Keep the debugger disabled until a client attaches.
      if (this._state === STATES.DETACHED) {
        this._dbg.disable();
      } else {
        this._dbg.enable();
      }
    }
    return this._dbg;
  }

  // Current state of the thread actor:
  //  - detached: state, before ThreadActor.attach is called,
  //  - exited: state, after the actor is destroyed,
  // States possible in between these two states:
  //  - running: default state, when the thread isn't paused,
  //  - paused: state, when paused on any type of breakpoint, or, when the client requested an interrupt.
  get state() {
    return this._state;
  }

  // XXX: soon to be equivalent to !isDestroyed once the thread actor is initialized on target creation.
  get attached() {
    return this.state == STATES.RUNNING || this.state == STATES.PAUSED;
  }

  get pauseLifetimePool() {
    return this._pausePool;
  }

  get threadLifetimePool() {
    if (!this._threadLifetimePool) {
      this._threadLifetimePool = new ObjectActorPool(this, "thread", true);
      this._threadLifetimePool.objectActors = new WeakMap();
    }
    return this._threadLifetimePool;
  }

  getThreadLifetimeObject(raw) {
    return this.threadLifetimePool.objectActors.get(raw);
  }

  promoteObjectToThreadLifetime(objectActor) {
    this.threadLifetimePool.manage(objectActor);
    this.threadLifetimePool.objectActors.set(objectActor.obj, objectActor);
  }

  get sourcesManager() {
    return this.targetActor.sourcesManager;
  }

  get breakpoints() {
    return this.targetActor.breakpoints;
  }

  get youngestFrame() {
    if (this.state != STATES.PAUSED) {
      return null;
    }
    return this.dbg.getNewestFrame();
  }

  get shouldSkipAnyBreakpoint() {
    return (
      // Disable all types of breakpoints if:
      // - the user explicitly requested it via the option
      this._options.skipBreakpoints ||
      // - or when we are evaluating some javascript via the console actor and disableBreaks
      //   has been set to true (which happens for most evaluating except the console input)
      this.insideClientEvaluation?.disableBreaks
    );
  }

  isPaused() {
    return this._state === STATES.PAUSED;
  }

  lastPausedPacket() {
    return this._priorPause;
  }

  /**
   * Remove all debuggees and clear out the thread's sources.
   */
  clearDebuggees() {
    if (this._dbg) {
      this.dbg.removeAllDebuggees();
    }
  }

  /**
   * Destroy the debugger and put the actor in the exited state.
   *
   * As part of destroy, we: clean up listeners, debuggees and
   * clear actor pools associated with the lifetime of this actor.
   */
  destroy() {
    dumpn("in ThreadActor.prototype.destroy");
    if (this._state == STATES.PAUSED) {
      this.doResume();
    }

    this.removeAllWatchpoints();
    this._xhrBreakpoints = [];
    this._updateNetworkObserver();

    this._activeEventBreakpoints = new Set();
    this._debuggerNotificationObserver.removeListener(
      this._eventBreakpointListener
    );

    for (const global of this.dbg.getDebuggees()) {
      try {
        this._debuggerNotificationObserver.disconnect(
          global.unsafeDereference()
        );
      } catch (e) {}
    }

    this.targetActor.off("window-ready", this._onWindowReady);
    this.targetActor.off("will-navigate", this._onWillNavigate);
    this.targetActor.off("navigate", this._onNavigate);

    this.sourcesManager.off("newSource", this.onNewSourceEvent);
    this.clearDebuggees();
    this._threadLifetimePool.destroy();
    this._threadLifetimePool = null;
    this._dbg = null;
    this._state = STATES.EXITED;

    super.destroy();
  }

  /**
   * Tells if the thread actor has been initialized/attached on target creation
   * by the server codebase. (And not late, from the frontend, by the TargetMixinFront class)
   */
  isAttached() {
    return !!this.alreadyAttached;
  }

  // Request handlers
  attach(options) {
    // Note that the client avoids trying to call attach if already attached.
    // But just in case, avoid any possible duplicate call to attach.
    if (this.alreadyAttached) {
      return;
    }

    if (this.state === STATES.EXITED) {
      throw {
        error: "exited",
        message: "threadActor has exited",
      };
    }

    if (this.state !== STATES.DETACHED) {
      throw {
        error: "wrongState",
        message: "Current state is " + this.state,
      };
    }

    this.dbg.onDebuggerStatement = this.onDebuggerStatement;
    this.dbg.onNewScript = this.onNewScript;
    this.dbg.onNewDebuggee = this._onNewDebuggee;

    this.sourcesManager.on("newSource", this.onNewSourceEvent);

    this.reconfigure(options);

    // Switch state from DETACHED to RUNNING
    this._state = STATES.RUNNING;

    this.alreadyAttached = true;
    this.dbg.enable();

    if (Services.obs) {
      // Set a wrappedJSObject property so |this| can be sent via the observer service
      // for the xpcshell harness.
      this.wrappedJSObject = this;
      Services.obs.notifyObservers(this, "devtools-thread-ready");
    }
  }

  toggleEventLogging(logEventBreakpoints) {
    this._options.logEventBreakpoints = logEventBreakpoints;
    return this._options.logEventBreakpoints;
  }

  get pauseOverlay() {
    if (this._pauseOverlay) {
      return this._pauseOverlay;
    }

    const env = new HighlighterEnvironment();
    env.initFromTargetActor(this.targetActor);
    const highlighter = new PausedDebuggerOverlay(env, {
      resume: () => this.resume(null),
      stepOver: () => this.resume({ type: "next" }),
    });
    this._pauseOverlay = highlighter;
    return highlighter;
  }

  _canShowOverlay() {
    // Only attempt to show on overlay on WindowGlobal targets, which displays a document.
    // Workers and content processes can't display any overlay.
    if (this.targetActor.targetType != Targets.TYPES.FRAME) {
      return false;
    }

    const { window } = this.targetActor;

    // The CanvasFrameAnonymousContentHelper class we're using to create the paused overlay
    // need to have access to a documentElement.
    // We might have access to a non-chrome window getter that is a Sandox (e.g. in the
    // case of ContentProcessTargetActor).
    if (!window?.document?.documentElement) {
      return false;
    }

    // Ignore privileged document (top level window, special about:* pages, …).
    if (window.isChromeWindow) {
      return false;
    }

    return true;
  }

  async showOverlay() {
    if (
      !this._shouldShowPauseOverlay ||
      !this.isPaused() ||
      !this._canShowOverlay()
    ) {
      return;
    }

    const reason = this._priorPause.why.type;
    await this.pauseOverlay.isReady;

    // we might not be paused anymore.
    if (!this.isPaused()) {
      return;
    }

    this.pauseOverlay.show(reason);
  }

  hideOverlay() {
    if (this._canShowOverlay() && this._pauseOverlay) {
      this.pauseOverlay.hide();
    }
  }

  /**
   * Tell the thread to automatically add a breakpoint on the first line of
   * a given file, when it is first loaded.
   *
   * This is currently only used by the xpcshell test harness, and unless
   * we decide to expand the scope of this feature, we should keep it that way.
   */
  setBreakpointOnLoad(urls) {
    this._onLoadBreakpointURLs = new Set(urls);
  }

  _findXHRBreakpointIndex(p, m) {
    return this._xhrBreakpoints.findIndex(
      ({ path, method }) => path === p && method === m
    );
  }

  // We clear the priorPause field when a breakpoint is added or removed
  // at the same location because we are no longer worried about pausing twice
  // at that location (e.g. debugger statement, stepping).
  _maybeClearPriorPause(location) {
    if (!this._priorPause) {
      return;
    }

    const { where } = this._priorPause.frame;
    if (where.line === location.line && where.column === location.column) {
      this._priorPause = null;
    }
  }

  async setBreakpoint(location, options) {
    // Automatically initialize the thread actor if it wasn't yet done.
    // Note that ideally, it should rather be done via reconfigure/thread configuration.
    if (this._state === STATES.DETACHED) {
      this.attach({});
      this.addAllSources();
    }

    let actor = this.breakpointActorMap.get(location);
    // Avoid resetting the exact same breakpoint twice
    if (actor && JSON.stringify(actor.options) == JSON.stringify(options)) {
      return;
    }
    if (!actor) {
      actor = this.breakpointActorMap.getOrCreateBreakpointActor(location);
    }
    actor.setOptions(options);
    this._maybeClearPriorPause(location);

    if (location.sourceUrl) {
      // There can be multiple source actors for a URL if there are multiple
      // inline sources on an HTML page.
      const sourceActors = this.sourcesManager.getSourceActorsByURL(
        location.sourceUrl
      );
      for (const sourceActor of sourceActors) {
        await sourceActor.applyBreakpoint(actor);
      }
    } else {
      const sourceActor = this.sourcesManager.getSourceActorById(
        location.sourceId
      );
      if (sourceActor) {
        await sourceActor.applyBreakpoint(actor);
      }
    }
  }

  removeBreakpoint(location) {
    const actor = this.breakpointActorMap.getOrCreateBreakpointActor(location);
    this._maybeClearPriorPause(location);
    actor.delete();
  }

  removeAllXHRBreakpoints() {
    this._xhrBreakpoints = [];
    return this._updateNetworkObserver();
  }

  removeXHRBreakpoint(path, method) {
    const index = this._findXHRBreakpointIndex(path, method);

    if (index >= 0) {
      this._xhrBreakpoints.splice(index, 1);
    }
    return this._updateNetworkObserver();
  }

  setXHRBreakpoint(path, method) {
    // request.path is a string,
    // If requested url contains the path, then we pause.
    const index = this._findXHRBreakpointIndex(path, method);

    if (index === -1) {
      this._xhrBreakpoints.push({ path, method });
    }
    return this._updateNetworkObserver();
  }

  getAvailableEventBreakpoints() {
    return getAvailableEventBreakpoints(this.targetActor.targetGlobal);
  }
  getActiveEventBreakpoints() {
    return Array.from(this._activeEventBreakpoints);
  }

  /**
   * Add event breakpoints to the list of active event breakpoints
   *
   * @param {Array<String>} ids: events to add (e.g. ["event.mouse.click","event.mouse.mousedown"])
   */
  addEventBreakpoints(ids) {
    this.setActiveEventBreakpoints(
      this.getActiveEventBreakpoints().concat(ids)
    );
  }

  /**
   * Remove event breakpoints from the list of active event breakpoints
   *
   * @param {Array<String>} ids: events to remove (e.g. ["event.mouse.click","event.mouse.mousedown"])
   */
  removeEventBreakpoints(ids) {
    this.setActiveEventBreakpoints(
      this.getActiveEventBreakpoints().filter(eventBp => !ids.includes(eventBp))
    );
  }

  /**
   * Set the the list of active event breakpoints
   *
   * @param {Array<String>} ids: events to add breakpoint for (e.g. ["event.mouse.click","event.mouse.mousedown"])
   */
  setActiveEventBreakpoints(ids) {
    this._activeEventBreakpoints = new Set(ids);

    if (eventsRequireNotifications(ids)) {
      this._debuggerNotificationObserver.addListener(
        this._eventBreakpointListener
      );
    } else {
      this._debuggerNotificationObserver.removeListener(
        this._eventBreakpointListener
      );
    }

    if (this._activeEventBreakpoints.has(firstStatementBreakpointId())) {
      this._ensureFirstStatementBreakpointInitialized();

      this._firstStatementBreakpoint.hit = frame =>
        this._pauseAndRespondEventBreakpoint(
          frame,
          firstStatementBreakpointId()
        );
    } else if (this._firstStatementBreakpoint) {
      // Disabling the breakpoint disables the feature as much as we need it
      // to. We do not bother removing breakpoints from the scripts themselves
      // here because the breakpoints will be a no-op if `hit` is `null`, and
      // if we wanted to remove them, we'd need a way to iterate through them
      // all, which would require us to hold strong references to them, which
      // just isn't needed. Plus, if the user disables and then re-enables the
      // feature again later, the breakpoints will still be there to work.
      this._firstStatementBreakpoint.hit = null;
    }
  }

  _ensureFirstStatementBreakpointInitialized() {
    if (this._firstStatementBreakpoint) {
      return;
    }

    this._firstStatementBreakpoint = { hit: null };
    for (const script of this.dbg.findScripts()) {
      this._maybeTrackFirstStatementBreakpoint(script);
    }
  }

  _maybeTrackFirstStatementBreakpointForNewGlobal(global) {
    if (this._firstStatementBreakpoint) {
      for (const script of this.dbg.findScripts({ global })) {
        this._maybeTrackFirstStatementBreakpoint(script);
      }
    }
  }

  _maybeTrackFirstStatementBreakpoint(script) {
    if (
      // If the feature is not enabled yet, there is nothing to do.
      !this._firstStatementBreakpoint ||
      // WASM files don't have a first statement.
      script.format !== "js" ||
      // All "top-level" scripts are non-functions, whether that's because
      // the script is a module, a global script, or an eval or what.
      script.isFunction
    ) {
      return;
    }

    const bps = script.getPossibleBreakpoints();

    // Scripts aren't guaranteed to have a step start if for instance the
    // file contains only function declarations, so in that case we try to
    // fall back to whatever we can find.
    let meta = bps.find(bp => bp.isStepStart) || bps[0];
    if (!meta) {
      // We've tried to avoid using `getAllColumnOffsets()` because the set of
      // locations included in this list is very under-defined, but for this
      // usecase it's not the end of the world. Maybe one day we could have an
      // "onEnterFrame" that was scoped to a specific script to avoid this.
      meta = script.getAllColumnOffsets()[0];
    }

    if (!meta) {
      // Not certain that this is actually possible, but including for sanity
      // so that we don't throw unexpectedly.
      return;
    }
    script.setBreakpoint(meta.offset, this._firstStatementBreakpoint);
  }

  _onNewDebuggee(global) {
    this._maybeTrackFirstStatementBreakpointForNewGlobal(global);
    try {
      this._debuggerNotificationObserver.connect(global.unsafeDereference());
    } catch (e) {}
  }

  _updateNetworkObserver() {
    // Workers don't have access to `Services` and even if they did, network
    // requests are all dispatched to the main thread, so there would be
    // nothing here to listen for. We'll need to revisit implementing
    // XHR breakpoints for workers.
    if (isWorker) {
      return false;
    }

    if (this._xhrBreakpoints.length && !this._observingNetwork) {
      this._observingNetwork = true;
      Services.obs.addObserver(
        this._onOpeningRequest,
        "http-on-opening-request"
      );
    } else if (this._xhrBreakpoints.length === 0 && this._observingNetwork) {
      this._observingNetwork = false;
      Services.obs.removeObserver(
        this._onOpeningRequest,
        "http-on-opening-request"
      );
    }

    return true;
  }

  _onOpeningRequest(subject) {
    if (this.shouldSkipAnyBreakpoint) {
      return;
    }

    const channel = subject.QueryInterface(Ci.nsIHttpChannel);
    const url = channel.URI.asciiSpec;
    const requestMethod = channel.requestMethod;

    let causeType = Ci.nsIContentPolicy.TYPE_OTHER;
    if (channel.loadInfo) {
      causeType = channel.loadInfo.externalContentPolicyType;
    }

    const isXHR =
      causeType === Ci.nsIContentPolicy.TYPE_XMLHTTPREQUEST ||
      causeType === Ci.nsIContentPolicy.TYPE_FETCH;

    if (!isXHR) {
      // We currently break only if the request is either fetch or xhr
      return;
    }

    let shouldPause = false;
    for (const { path, method } of this._xhrBreakpoints) {
      if (method !== "ANY" && method !== requestMethod) {
        continue;
      }
      if (url.includes(path)) {
        shouldPause = true;
        break;
      }
    }

    if (shouldPause) {
      const frame = this.dbg.getNewestFrame();

      // If there is no frame, this request was dispatched by logic that isn't
      // primarily JS, so pausing the event loop wouldn't make sense.
      // This covers background requests like loading the initial page document,
      // or loading favicons. This also includes requests dispatched indirectly
      // from workers. We'll need to handle them separately in the future.
      if (frame) {
        this._pauseAndRespond(frame, { type: PAUSE_REASONS.XHR });
      }
    }
  }

  reconfigure(options = {}) {
    if (this.state == STATES.EXITED) {
      throw {
        error: "wrongState",
      };
    }
    this._options = { ...this._options, ...options };

    if ("observeAsmJS" in options) {
      this.dbg.allowUnobservedAsmJS = !options.observeAsmJS;
    }
    if ("observeWasm" in options) {
      this.dbg.allowUnobservedWasm = !options.observeWasm;
    }
    if ("pauseOverlay" in options) {
      this._shouldShowPauseOverlay = !!options.pauseOverlay;
    }

    if (
      "pauseWorkersUntilAttach" in options &&
      this.targetActor.pauseWorkersUntilAttach
    ) {
      this.targetActor.pauseWorkersUntilAttach(options.pauseWorkersUntilAttach);
    }

    if (options.breakpoints) {
      for (const breakpoint of Object.values(options.breakpoints)) {
        this.setBreakpoint(breakpoint.location, breakpoint.options);
      }
    }

    if (options.eventBreakpoints) {
      this.setActiveEventBreakpoints(options.eventBreakpoints);
    }

    // Only consider this options if an explicit boolean value is passed.
    if (typeof this._options.shouldPauseOnDebuggerStatement == "boolean") {
      this.setPauseOnDebuggerStatement(
        this._options.shouldPauseOnDebuggerStatement
      );
    }
    this.setPauseOnExceptions(this._options.pauseOnExceptions);
  }

  _eventBreakpointListener(notification) {
    if (this._state === STATES.PAUSED || this._state === STATES.DETACHED) {
      return;
    }

    const eventBreakpoint = eventBreakpointForNotification(
      this.dbg,
      notification
    );

    if (!this._activeEventBreakpoints.has(eventBreakpoint)) {
      return;
    }

    if (notification.phase === "pre" && !this._activeEventPause) {
      this._activeEventPause = this._captureDebuggerHooks();

      this.dbg.onEnterFrame =
        this._makeEventBreakpointEnterFrame(eventBreakpoint);
    } else if (notification.phase === "post" && this._activeEventPause) {
      this._restoreDebuggerHooks(this._activeEventPause);
      this._activeEventPause = null;
    } else if (!notification.phase && !this._activeEventPause) {
      const frame = this.dbg.getNewestFrame();
      if (frame) {
        if (this.sourcesManager.isFrameBlackBoxed(frame)) {
          return;
        }

        this._pauseAndRespondEventBreakpoint(frame, eventBreakpoint);
      }
    }
  }

  _makeEventBreakpointEnterFrame(eventBreakpoint) {
    return frame => {
      if (this.sourcesManager.isFrameBlackBoxed(frame)) {
        return undefined;
      }

      this._restoreDebuggerHooks(this._activeEventPause);
      this._activeEventPause = null;

      return this._pauseAndRespondEventBreakpoint(frame, eventBreakpoint);
    };
  }

  _pauseAndRespondEventBreakpoint(frame, eventBreakpoint) {
    if (this.shouldSkipAnyBreakpoint) {
      return undefined;
    }

    if (this._options.logEventBreakpoints) {
      return logEvent({
        threadActor: this,
        frame,
        level: "logPoint",
        expression: `[_event]`,
        bindings: { _event: frame.arguments[0] },
      });
    }

    return this._pauseAndRespond(frame, {
      type: PAUSE_REASONS.EVENT_BREAKPOINT,
      breakpoint: eventBreakpoint,
      message: makeEventBreakpointMessage(eventBreakpoint),
    });
  }

  _captureDebuggerHooks() {
    return {
      onEnterFrame: this.dbg.onEnterFrame,
      onStep: this.dbg.onStep,
      onPop: this.dbg.onPop,
    };
  }

  _restoreDebuggerHooks(hooks) {
    this.dbg.onEnterFrame = hooks.onEnterFrame;
    this.dbg.onStep = hooks.onStep;
    this.dbg.onPop = hooks.onPop;
  }

  /**
   * Pause the debuggee, by entering a nested event loop, and return a 'paused'
   * packet to the client.
   *
   * @param Debugger.Frame frame
   *        The newest debuggee frame in the stack.
   * @param object reason
   *        An object with a 'type' property containing the reason for the pause.
   * @param function onPacket
   *        Hook to modify the packet before it is sent. Feel free to return a
   *        promise.
   */
  _pauseAndRespond(frame, reason, onPacket = k => k) {
    try {
      const packet = this._paused(frame);
      if (!packet) {
        return undefined;
      }

      const { sourceActor, line, column } =
        this.sourcesManager.getFrameLocation(frame);

      packet.why = reason;

      if (!sourceActor) {
        // If the frame location is in a source that not pass the 'isHiddenSource'
        // check and thus has no actor, we do not bother pausing.
        return undefined;
      }

      packet.frame.where = {
        actor: sourceActor.actorID,
        line,
        column,
      };
      const pkt = onPacket(packet);

      this._priorPause = pkt;
      this.emit("paused", pkt);
      this.showOverlay();
    } catch (error) {
      reportException("DBG-SERVER", error);
      this.conn.send({
        error: "unknownError",
        message: error.message + "\n" + error.stack,
      });
      return undefined;
    }

    try {
      this._nestedEventLoop.enter();
    } catch (e) {
      reportException("TA__pauseAndRespond", e);
    }

    if (this._requestedFrameRestart) {
      return null;
    }

    // If the parent actor has been closed, terminate the debuggee script
    // instead of continuing. Executing JS after the content window is gone is
    // a bad idea.
    return this._targetActorClosed ? null : undefined;
  }

  _makeOnEnterFrame() {
    return frame => {
      if (this._requestedFrameRestart) {
        return null;
      }

      // Continue forward until we get to a valid step target.
      const { onStep, onPop } = this._makeSteppingHooks({
        steppingType: "next",
      });

      if (this.sourcesManager.isFrameBlackBoxed(frame)) {
        return undefined;
      }

      frame.onStep = onStep;
      frame.onPop = onPop;
      return undefined;
    };
  }

  _makeOnPop({ pauseAndRespond, steppingType }) {
    const thread = this;
    return function (completion) {
      if (thread._requestedFrameRestart === this) {
        return thread.restartFrame(this);
      }

      // onPop is called when we temporarily leave an async/generator
      if (steppingType != "finish" && (completion.await || completion.yield)) {
        thread.suspendedFrame = this;
        thread.dbg.onEnterFrame = undefined;
        return undefined;
      }

      // Note that we're popping this frame; we need to watch for
      // subsequent step events on its caller.
      this.reportedPop = true;

      // Cache the frame so that the onPop and onStep hooks are cleared
      // on the next pause.
      thread.suspendedFrame = this;

      if (
        steppingType != "finish" &&
        !thread.sourcesManager.isFrameBlackBoxed(this)
      ) {
        const pauseAndRespValue = pauseAndRespond(this, packet =>
          thread.createCompletionGrip(packet, completion)
        );

        // If the requested frame to restart differs from this frame, we don't
        // need to restart it at this point.
        if (thread._requestedFrameRestart === this) {
          return thread.restartFrame(this);
        }

        return pauseAndRespValue;
      }

      thread._attachSteppingHooks(this, "next", completion);
      return undefined;
    };
  }

  restartFrame(frame) {
    this._requestedFrameRestart = null;
    this._priorPause = null;

    if (
      frame.type !== "call" ||
      frame.script.isGeneratorFunction ||
      frame.script.isAsyncFunction
    ) {
      return undefined;
    }
    RESTARTED_FRAMES.add(frame);

    const completion = frame.callee.apply(frame.this, frame.arguments);

    return completion;
  }

  hasMoved(frame, newType) {
    const newLocation = this.sourcesManager.getFrameLocation(frame);

    if (!this._priorPause) {
      return true;
    }

    // Recursion/Loops makes it okay to resume and land at
    // the same breakpoint or debugger statement.
    // It is not okay to transition from a breakpoint to debugger statement
    // or a step to a debugger statement.
    const { type } = this._priorPause.why;

    // Conditional breakpoint are doing something weird as they are using "breakpoint" type
    // unless they throw in which case they will be "breakpointConditionThrown".
    if (
      type == newType ||
      (type == "breakpointConditionThrown" && newType == "breakpoint")
    ) {
      return true;
    }

    const { line, column } = this._priorPause.frame.where;
    return line !== newLocation.line || column !== newLocation.column;
  }

  _makeOnStep({ pauseAndRespond, startFrame, completion }) {
    const thread = this;
    return function () {
      if (thread._validFrameStepOffset(this, startFrame, this.offset)) {
        return pauseAndRespond(this, packet =>
          thread.createCompletionGrip(packet, completion)
        );
      }

      return undefined;
    };
  }

  _validFrameStepOffset(frame, startFrame, offset) {
    const meta = frame.script.getOffsetMetadata(offset);

    // Continue if:
    // 1. the location is not a valid breakpoint position
    // 2. the source is blackboxed
    // 3. we have not moved since the last pause
    if (
      !meta.isBreakpoint ||
      this.sourcesManager.isFrameBlackBoxed(frame) ||
      !this.hasMoved(frame)
    ) {
      return false;
    }

    // Pause if:
    // 1. the frame has changed
    // 2. the location is a step position.
    return frame !== startFrame || meta.isStepStart;
  }

  atBreakpointLocation(frame) {
    const location = this.sourcesManager.getFrameLocation(frame);
    return !!this.breakpointActorMap.get(location);
  }

  createCompletionGrip(packet, completion) {
    if (!completion) {
      return packet;
    }

    packet.why.frameFinished = {};

    if (completion.hasOwnProperty("return")) {
      packet.why.frameFinished.return = this.createValueGrip(completion.return);
    } else if (completion.hasOwnProperty("yield")) {
      packet.why.frameFinished.return = this.createValueGrip(completion.yield);
    } else if (completion.hasOwnProperty("throw")) {
      packet.why.frameFinished.throw = this.createValueGrip(completion.throw);
    }

    return packet;
  }

  /**
   * Define the JS hook functions for stepping.
   */
  _makeSteppingHooks({ steppingType, startFrame, completion }) {
    // Bind these methods and state because some of the hooks are called
    // with 'this' set to the current frame. Rather than repeating the
    // binding in each _makeOnX method, just do it once here and pass it
    // in to each function.
    const steppingHookState = {
      pauseAndRespond: (frame, onPacket = k => k) =>
        this._pauseAndRespond(
          frame,
          { type: PAUSE_REASONS.RESUME_LIMIT },
          onPacket
        ),
      startFrame: startFrame || this.youngestFrame,
      steppingType,
      completion,
    };

    return {
      onEnterFrame: this._makeOnEnterFrame(steppingHookState),
      onPop: this._makeOnPop(steppingHookState),
      onStep: this._makeOnStep(steppingHookState),
    };
  }

  /**
   * Handle attaching the various stepping hooks we need to attach when we
   * receive a resume request with a resumeLimit property.
   *
   * @param Object { resumeLimit }
   *        The values received over the RDP.
   * @returns A promise that resolves to true once the hooks are attached, or is
   *          rejected with an error packet.
   */
  async _handleResumeLimit({ resumeLimit, frameActorID }) {
    const steppingType = resumeLimit.type;
    if (
      !["break", "step", "next", "finish", "restart"].includes(steppingType)
    ) {
      return Promise.reject({
        error: "badParameterType",
        message: "Unknown resumeLimit type",
      });
    }

    let frame = this.youngestFrame;

    if (frameActorID) {
      frame = this._framesPool.getActorByID(frameActorID).frame;
      if (!frame) {
        throw new Error("Frame should exist in the frames pool.");
      }
    }

    if (steppingType === "restart") {
      if (
        frame.type !== "call" ||
        frame.script.isGeneratorFunction ||
        frame.script.isAsyncFunction
      ) {
        return undefined;
      }
      this._requestedFrameRestart = frame;
    }

    return this._attachSteppingHooks(frame, steppingType, undefined);
  }

  _attachSteppingHooks(frame, steppingType, completion) {
    // If we are stepping out of the onPop handler, we want to use "next" mode
    // so that the parent frame's handlers behave consistently.
    if (steppingType === "finish" && frame.reportedPop) {
      steppingType = "next";
    }

    // If there are no more frames on the stack, use "step" mode so that we will
    // pause on the next script to execute.
    const stepFrame = this._getNextStepFrame(frame);
    if (!stepFrame) {
      steppingType = "step";
    }

    const { onEnterFrame, onPop, onStep } = this._makeSteppingHooks({
      steppingType,
      completion,
      startFrame: frame,
    });

    if (steppingType === "step" || steppingType === "restart") {
      this.dbg.onEnterFrame = onEnterFrame;
    }

    if (stepFrame) {
      switch (steppingType) {
        case "step":
        case "break":
        case "next":
          if (stepFrame.script) {
            if (!this.sourcesManager.isFrameBlackBoxed(stepFrame)) {
              stepFrame.onStep = onStep;
            }
          }
        // eslint-disable-next-line no-fallthrough
        case "finish":
          stepFrame.onStep = createStepForReactionTracking(stepFrame.onStep);
        // eslint-disable-next-line no-fallthrough
        case "restart":
          stepFrame.onPop = onPop;
          break;
      }
    }

    return true;
  }

  /**
   * Clear the onStep and onPop hooks for all frames on the stack.
   */
  _clearSteppingHooks() {
    if (this.suspendedFrame) {
      this.suspendedFrame.onStep = undefined;
      this.suspendedFrame.onPop = undefined;
      this.suspendedFrame = undefined;
    }

    let frame = this.youngestFrame;
    if (frame?.onStack) {
      while (frame) {
        frame.onStep = undefined;
        frame.onPop = undefined;
        frame = frame.older;
      }
    }
  }

  /**
   * Handle a protocol request to resume execution of the debuggee.
   */
  async resume(resumeLimit, frameActorID) {
    if (this._state !== STATES.PAUSED) {
      return {
        error: "wrongState",
        message:
          "Can't resume when debuggee isn't paused. Current state is '" +
          this._state +
          "'",
        state: this._state,
      };
    }

    // In case of multiple nested event loops (due to multiple debuggers open in
    // different tabs or multiple devtools clients connected to the same tab)
    // only allow resumption in a LIFO order.
    if (!this._nestedEventLoop.isTheLastPausedThreadActor()) {
      return {
        error: "wrongOrder",
        message: "trying to resume in the wrong order.",
      };
    }

    try {
      if (resumeLimit) {
        await this._handleResumeLimit({ resumeLimit, frameActorID });
      } else {
        this._clearSteppingHooks();
      }

      this.doResume({ resumeLimit });
      return {};
    } catch (error) {
      return error instanceof Error
        ? {
            error: "unknownError",
            message: DevToolsUtils.safeErrorString(error),
          }
        : // It is a known error, and the promise was rejected with an error
          // packet.
          error;
    }
  }

  /**
   * Only resume and notify necessary observers. This should be used in cases
   * when we do not want to notify the front end of a resume, for example when
   * we are shutting down.
   */
  doResume() {
    this._state = STATES.RUNNING;

    // Drop the actors in the pause actor pool.
    this._pausePool.destroy();
    this._pausePool = null;

    this._pauseActor = null;
    this._nestedEventLoop.exit();

    // Tell anyone who cares of the resume (as of now, that's the xpcshell harness and
    // devtools-startup.js when handling the --wait-for-jsdebugger flag)
    this.emit("resumed");
    this.hideOverlay();
  }

  /**
   * Set the debugging hook to pause on exceptions if configured to do so.
   *
   * Note that this is also called when evaluating conditional breakpoints.
   *
   * @param {Boolean} doPause
   *        Should watch for pause or not. `_onExceptionUnwind` function will
   *        then be notified about new caught or uncaught exception being fired.
   */
  setPauseOnExceptions(doPause) {
    if (doPause) {
      this.dbg.onExceptionUnwind = this._onExceptionUnwind;
    } else {
      this.dbg.onExceptionUnwind = undefined;
    }
  }

  /**
   * Set the debugging hook to pause on debugger statement if configured to do so.
   *
   * Note that the thread actor will pause on exception by default.
   * This method has to be called with a falsy value to disable it.
   *
   * @param {Boolean} doPause
   *        Controls whether we should or should not pause on debugger statement.
   */
  setPauseOnDebuggerStatement(doPause) {
    this.dbg.onDebuggerStatement = doPause
      ? this.onDebuggerStatement
      : undefined;
  }

  isPauseOnExceptionsEnabled() {
    return this.dbg.onExceptionUnwind == this._onExceptionUnwind;
  }

  /**
   * Helper method that returns the next frame when stepping.
   */
  _getNextStepFrame(frame) {
    const endOfFrame = frame.reportedPop;
    const stepFrame = endOfFrame
      ? frame.older || getAsyncParentFrame(frame)
      : frame;
    if (!stepFrame || !stepFrame.script) {
      return null;
    }

    // Skips a frame that has been restarted.
    if (RESTARTED_FRAMES.has(stepFrame)) {
      return this._getNextStepFrame(stepFrame.older);
    }

    return stepFrame;
  }

  frames(start, count) {
    if (this.state !== STATES.PAUSED) {
      return {
        error: "wrongState",
        message:
          "Stack frames are only available while the debuggee is paused.",
      };
    }

    // Find the starting frame...
    let frame = this.youngestFrame;

    const walkToParentFrame = () => {
      if (!frame) {
        return;
      }

      const currentFrame = frame;
      frame = null;

      if (!(currentFrame instanceof Debugger.Frame)) {
        frame = getSavedFrameParent(this, currentFrame);
      } else if (currentFrame.older) {
        frame = currentFrame.older;
      } else if (
        this._options.shouldIncludeSavedFrames &&
        currentFrame.olderSavedFrame
      ) {
        frame = currentFrame.olderSavedFrame;
        if (frame && !isValidSavedFrame(this, frame)) {
          frame = null;
        }
      } else if (
        this._options.shouldIncludeAsyncLiveFrames &&
        currentFrame.asyncPromise
      ) {
        const asyncFrame = getAsyncParentFrame(currentFrame);
        if (asyncFrame) {
          frame = asyncFrame;
        }
      }
    };

    let i = 0;
    while (frame && i < start) {
      walkToParentFrame();
      i++;
    }

    // Return count frames, or all remaining frames if count is not defined.
    const frames = [];
    for (; frame && (!count || i < start + count); i++, walkToParentFrame()) {
      // SavedFrame instances don't have direct Debugger.Source object. If
      // there is an active Debugger.Source that represents the SaveFrame's
      // source, it will have already been created in the server.
      if (frame instanceof Debugger.Frame) {
        this.sourcesManager.createSourceActor(frame.script.source);
      }

      if (RESTARTED_FRAMES.has(frame)) {
        continue;
      }

      const frameActor = this._createFrameActor(frame, i);
      frames.push(frameActor);
    }

    return { frames };
  }

  addAllSources() {
    // This method aims at instantiating Source Actors for all already existing
    // sources (via `_addSource()`).
    // This is called on each new target instantiation:
    //   * when a new document or debugging context is instantiated. This
    //     method should be a no-op as there should be no pre-existing sources.
    //   * when devtools open. This time there might be pre-existing sources.
    //
    // We are using Debugger API `findSources()` for instantating source actors
    // of all still-active sources. But we want to also "resurrect" sources
    // which ran before DevTools were opened and were garbaged collected.
    // `findSources()` won't return them.
    // Debugger API `findSourceURLs()` will return the source URLs of all the
    // sources, GC-ed and still active ones.
    //
    // We are using `urlMap` to identify the GC-ed sources.
    //
    // We have two special edgecases:
    //
    // # HTML sources and inline <script> tags
    //
    // HTML sources will be specific to a given URL, but may relate to multiple
    // inline <script> tag. Each script will be related to a given Debugger API
    // source and a given DevTools Source Actor.
    // We collect all active sources in `urlMap`'s `sources` array so that we
    // only resurrect the GC-ed inline <script> and not the one which are still
    // active.
    //
    // # asm.js / wasm
    //
    // DevTools toggles Debugger API `allowUnobservedAsmJS` and
    // `allowUnobservedWasm` to false on opening. This changes how asm.js and
    // Wasm sources are compiled. But only to sources created after DevTools
    // are opened. This typically requires to reload the page.
    //
    // Before DevTools are opened, the asm.js functions are compiled into wasm
    // instances, and they are visible as "wasm" sources in `findSources()`.
    // The wasm instance doesn't keep the top-level normal JS script and the
    // corresponding JS source alive. If only the "wasm" source is found for
    // certain URL, the source needs to be re-compiled.
    //
    // Here, we should be careful to re-compile these sources the way they were
    // compiled before DevTools opening. Otherwise the re-compilation will
    // create Debugger.Script instances backed by normal JS functions for those
    // asm.js functions, which results in an inconsistency between what's
    // running in the debuggee and what's shown in DevTools.
    //
    // We are using `urlMap`'s `hasWasm` to flag them and instruct
    // `resurrectSource()` to re-compile the sources as if DevTools was off and
    // without debugging ability.
    const urlMap = {};
    for (const url of this.dbg.findSourceURLs()) {
      if (url !== "self-hosted") {
        if (!urlMap[url]) {
          urlMap[url] = { count: 0, sources: [], hasWasm: false };
        }
        urlMap[url].count++;
      }
    }

    const sources = this.dbg.findSources();

    for (const source of sources) {
      this._addSource(source);

      if (source.introductionType === "wasm") {
        const origURL = source.url.replace(/^wasm:/, "");
        if (urlMap[origURL]) {
          urlMap[origURL].hasWasm = true;
        }
      }

      // The following check should match the filtering done by `findSourceURLs`:
      // https://searchfox.org/mozilla-central/rev/ac7a567f036e1954542763f4722fbfce041fb752/js/src/debugger/Debugger.cpp#2406-2409
      // Otherwise we may populate `urlMap` incorrectly and resurrect sources that weren't GCed,
      // and spawn duplicated SourceActors/Debugger.Source for the same actual source.
      // `findSourceURLs` uses !introductionScript check as that allows to identify <script>'s
      // loaded from the HTML page. This boolean will be defined only when the <script> tag
      // is added by Javascript code at runtime.
      // https://searchfox.org/mozilla-central/rev/3d03a3ca09f03f06ef46a511446537563f62a0c6/devtools/docs/user/debugger-api/debugger.source/index.rst#113
      if (!source.introductionScript && urlMap[source.url]) {
        urlMap[source.url].count--;
        urlMap[source.url].sources.push(source);
      }
    }

    // Resurrect any URLs for which not all sources are accounted for.
    for (const [url, data] of Object.entries(urlMap)) {
      if (data.count > 0) {
        this._resurrectSource(url, data.sources, data.hasWasm);
      }
    }
  }

  sources() {
    this.addAllSources();

    // No need to flush the new source packets here, as we are sending the
    // list of sources out immediately and we don't need to invoke the
    // overhead of an RDP packet for every source right now. Let the default
    // timeout flush the buffered packets.

    const forms = [];
    for (const source of this.sourcesManager.iter()) {
      forms.push(source.form());
    }
    return forms;
  }

  /**
   * Disassociate all breakpoint actors from their scripts and clear the
   * breakpoint handlers. This method can be used when the thread actor intends
   * to keep the breakpoint store, but needs to clear any actual breakpoints,
   * e.g. due to a page navigation. This way the breakpoint actors' script
   * caches won't hold on to the Debugger.Script objects leaking memory.
   */
  disableAllBreakpoints() {
    for (const bpActor of this.breakpointActorMap.findActors()) {
      bpActor.removeScripts();
    }
  }

  removeAllBreakpoints() {
    this.breakpointActorMap.removeAllBreakpoints();
  }

  removeAllWatchpoints() {
    for (const actor of this.threadLifetimePool.poolChildren()) {
      if (actor.typeName == "obj") {
        actor.removeWatchpoints();
      }
    }
  }

  addWatchpoint(objActor, data) {
    this._watchpointsMap.add(objActor, data);
  }

  removeWatchpoint(objActor, property) {
    this._watchpointsMap.remove(objActor, property);
  }

  getWatchpoint(obj, property) {
    return this._watchpointsMap.get(obj, property);
  }

  /**
   * Handle a protocol request to pause the debuggee.
   */
  interrupt(when) {
    if (this.state == STATES.EXITED) {
      return { type: "exited" };
    } else if (this.state == STATES.PAUSED) {
      // TODO: return the actual reason for the existing pause.
      this.emit("paused", {
        why: { type: PAUSE_REASONS.ALREADY_PAUSED },
      });
      return {};
    } else if (this.state != STATES.RUNNING) {
      return {
        error: "wrongState",
        message: "Received interrupt request in " + this.state + " state.",
      };
    }
    try {
      // If execution should pause just before the next JavaScript bytecode is
      // executed, just set an onEnterFrame handler.
      if (when == "onNext") {
        const onEnterFrame = frame => {
          this._pauseAndRespond(frame, {
            type: PAUSE_REASONS.INTERRUPTED,
            onNext: true,
          });
        };
        this.dbg.onEnterFrame = onEnterFrame;
        return {};
      }

      // If execution should pause immediately, just put ourselves in the paused
      // state.
      const packet = this._paused();
      if (!packet) {
        return { error: "notInterrupted" };
      }
      packet.why = { type: PAUSE_REASONS.INTERRUPTED, onNext: false };

      // Send the response to the interrupt request now (rather than
      // returning it), because we're going to start a nested event loop
      // here.
      this.conn.send({ from: this.actorID, type: "interrupt" });
      this.emit("paused", packet);

      // Start a nested event loop.
      this._nestedEventLoop.enter();

      // We already sent a response to this request, don't send one
      // now.
      return null;
    } catch (e) {
      reportException("DBG-SERVER", e);
      return { error: "notInterrupted", message: e.toString() };
    }
  }

  _paused(frame) {
    // We don't handle nested pauses correctly.  Don't try - if we're
    // paused, just continue running whatever code triggered the pause.
    // We don't want to actually have nested pauses (although we
    // have nested event loops).  If code runs in the debuggee during
    // a pause, it should cause the actor to resume (dropping
    // pause-lifetime actors etc) and then repause when complete.

    if (this.state === STATES.PAUSED) {
      return undefined;
    }

    this._state = STATES.PAUSED;

    // Clear stepping hooks.
    this.dbg.onEnterFrame = undefined;
    this._requestedFrameRestart = null;
    this._clearSteppingHooks();

    // Create the actor pool that will hold the pause actor and its
    // children.
    assert(!this._pausePool, "No pause pool should exist yet");
    this._pausePool = new ObjectActorPool(this, "pause", true);

    // Give children of the pause pool a quick link back to the
    // thread...
    this._pausePool.threadActor = this;

    // Create the pause actor itself...
    assert(!this._pauseActor, "No pause actor should exist yet");
    this._pauseActor = new PauseActor(this._pausePool);
    this._pausePool.manage(this._pauseActor);

    // Update the list of frames.
    this._updateFrames();

    // Send off the paused packet and spin an event loop.
    const packet = {
      actor: this._pauseActor.actorID,
    };

    if (frame) {
      packet.frame = this._createFrameActor(frame);
    }

    return packet;
  }

  /**
   * Expire frame actors for frames that are no longer on the current stack.
   */
  _updateFrames() {
    // Create the actor pool that will hold the still-living frames.
    const framesPool = new Pool(this.conn, "frames");
    const frameList = [];

    for (const frameActor of this._frameActors) {
      if (frameActor.frame.onStack) {
        framesPool.manage(frameActor);
        frameList.push(frameActor);
      }
    }

    // Remove the old frame actor pool, this will expire
    // any actors that weren't added to the new pool.
    if (this._framesPool) {
      this._framesPool.destroy();
    }

    this._frameActors = frameList;
    this._framesPool = framesPool;
  }

  _createFrameActor(frame, depth) {
    let actor = this._frameActorMap.get(frame);
    if (!actor || actor.isDestroyed()) {
      actor = new FrameActor(frame, this, depth);
      this._frameActors.push(actor);
      this._framesPool.manage(actor);

      this._frameActorMap.set(frame, actor);
    }
    return actor;
  }

  /**
   * Create and return an environment actor that corresponds to the provided
   * Debugger.Environment.
   * @param Debugger.Environment environment
   *        The lexical environment we want to extract.
   * @param object pool
   *        The pool where the newly-created actor will be placed.
   * @return The EnvironmentActor for environment or undefined for host
   *         functions or functions scoped to a non-debuggee global.
   */
  createEnvironmentActor(environment, pool) {
    if (!environment) {
      return undefined;
    }

    if (environment.actor) {
      return environment.actor;
    }

    const actor = new EnvironmentActor(environment, this);
    pool.manage(actor);
    environment.actor = actor;

    return actor;
  }

  /**
   * Create a grip for the given debuggee value.
   * Depdending on if the thread is paused, the object actor may have a different lifetime:
   *  - when thread is paused, the object actor will be kept alive until the thread is resumed
   *    (which also happens when we step)
   *  - when thread is not paused, the object actor will be kept alive until the related target
   *    is destroyed (thread stops or devtools closes)
   *
   * @param value Debugger.Object|any
   *        A Debugger.Object for all JS objects, or any primitive JS type.
   * @return The value's grip
   *        Primitive JS type, Object actor Form JSON object, or a JSON object to describe the value.
   */
  createValueGrip(value) {
    // When the thread is paused, all objects are stored in a transient pool
    // which will be cleared on resume (which also happens when we step).
    const pool = this._pausePool || this.threadLifetimePool;

    return createValueGrip(this, value, pool);
  }

  _onWindowReady({ isTopLevel, isBFCache }) {
    // Note that this code relates to the disabling of Debugger API from will-navigate listener.
    // And should only be triggered when the target actor doesn't follow WindowGlobal lifecycle.
    // i.e. when the Thread Actor manages more than one top level WindowGlobal.
    if (isTopLevel && this.state != STATES.DETACHED) {
      this.sourcesManager.reset();
      this.clearDebuggees();
      this.dbg.enable();
    }

    // Refresh the debuggee list when a new window object appears (top window or
    // iframe).
    if (this.attached) {
      this.dbg.addDebuggees();
    }

    // BFCache navigations reuse old sources, so send existing sources to the
    // client instead of waiting for onNewScript debugger notifications.
    if (isBFCache) {
      this.addAllSources();
    }
  }

  _onWillNavigate({ isTopLevel }) {
    if (!isTopLevel) {
      return;
    }

    // Proceed normally only if the debuggee is not paused.
    if (this.state == STATES.PAUSED) {
      // If we were paused while navigating to a new page,
      // we resume previous page execution, so that the document can be sucessfully unloaded.
      // And we disable the Debugger API, so that we do not hit any breakpoint or trigger any
      // thread actor feature. We will re-enable it just before the next page starts loading,
      // from window-ready listener. That's for when the target doesn't follow WindowGlobal
      // lifecycle.
      // When the target follows the WindowGlobal lifecycle, we will stiff resume and disable
      // this thread actor. It will soon be destroyed. And a new target will pick up
      // the next WindowGlobal and spawn a new Debugger API, via ThreadActor.attach().
      this.doResume();
      this.dbg.disable();
    }

    this.removeAllWatchpoints();
    this.disableAllBreakpoints();
    this.dbg.onEnterFrame = undefined;
  }

  _onNavigate() {
    if (this.state == STATES.RUNNING) {
      this.dbg.enable();
    }
  }

  // JS Debugger API hooks.
  pauseForMutationBreakpoint(
    mutationType,
    targetNode,
    ancestorNode,
    action = "" // "add" or "remove"
  ) {
    if (
      !["subtreeModified", "nodeRemoved", "attributeModified"].includes(
        mutationType
      )
    ) {
      throw new Error("Unexpected mutation breakpoint type");
    }

    if (this.shouldSkipAnyBreakpoint) {
      return undefined;
    }

    const frame = this.dbg.getNewestFrame();
    if (!frame) {
      return undefined;
    }

    if (this.sourcesManager.isFrameBlackBoxed(frame)) {
      return undefined;
    }

    const global = (targetNode.ownerDocument || targetNode).defaultView;
    assert(global && this.dbg.hasDebuggee(global));

    const targetObj = this.dbg
      .makeGlobalObjectReference(global)
      .makeDebuggeeValue(targetNode);

    let ancestorObj = null;
    if (ancestorNode) {
      ancestorObj = this.dbg
        .makeGlobalObjectReference(global)
        .makeDebuggeeValue(ancestorNode);
    }

    return this._pauseAndRespond(
      frame,
      {
        type: PAUSE_REASONS.MUTATION_BREAKPOINT,
        mutationType,
        message: `DOM Mutation: '${mutationType}'`,
      },
      pkt => {
        // We have to create the object actors late, from here because `_pausePool` is `null` beforehand,
        // and the actors created by createValueGrip would otherwise be registered in the thread lifetime pool
        pkt.why.nodeGrip = this.createValueGrip(targetObj);
        pkt.why.ancestorGrip = ancestorObj
          ? this.createValueGrip(ancestorObj)
          : null;
        pkt.why.action = action;
        return pkt;
      }
    );
  }

  /**
   * A function that the engine calls when a debugger statement has been
   * executed in the specified frame.
   *
   * @param frame Debugger.Frame
   *        The stack frame that contained the debugger statement.
   */
  onDebuggerStatement(frame) {
    // Don't pause if:
    // 1. breakpoints are disabled
    // 2. we have not moved since the last pause
    // 3. the source is blackboxed
    // 4. there is a breakpoint at the same location
    if (
      this.shouldSkipAnyBreakpoint ||
      !this.hasMoved(frame, "debuggerStatement") ||
      this.sourcesManager.isFrameBlackBoxed(frame) ||
      this.atBreakpointLocation(frame)
    ) {
      return undefined;
    }

    return this._pauseAndRespond(frame, {
      type: PAUSE_REASONS.DEBUGGER_STATEMENT,
    });
  }

  skipBreakpoints(skip) {
    this._options.skipBreakpoints = skip;
    return { skip };
  }

  // Bug 1686485 is meant to remove usages of this request
  // in favor direct call to `reconfigure`
  pauseOnExceptions(pauseOnExceptions, ignoreCaughtExceptions) {
    this.reconfigure({
      pauseOnExceptions,
      ignoreCaughtExceptions,
    });
    return {};
  }

  /**
   * A function that the engine calls when an exception has been thrown and has
   * propagated to the specified frame.
   *
   * @param youngestFrame Debugger.Frame
   *        The youngest remaining stack frame.
   * @param value object
   *        The exception that was thrown.
   */
  _onExceptionUnwind(youngestFrame, value) {
    // Ignore any reported exception if we are already paused
    if (this.isPaused()) {
      return undefined;
    }

    // Ignore shouldSkipAnyBreakpoint if we are explicitly requested to do so.
    // Typically, when we are evaluating conditional breakpoints, we want to report any exception.
    if (
      this.shouldSkipAnyBreakpoint &&
      !this.insideClientEvaluation?.reportExceptionsWhenBreaksAreDisabled
    ) {
      return undefined;
    }

    let willBeCaught = false;
    for (let frame = youngestFrame; frame != null; frame = frame.older) {
      if (frame.script.isInCatchScope(frame.offset)) {
        willBeCaught = true;
        break;
      }
    }

    if (willBeCaught && this._options.ignoreCaughtExceptions) {
      return undefined;
    }

    if (
      this._handledFrameExceptions.has(youngestFrame) &&
      this._handledFrameExceptions.get(youngestFrame) === value
    ) {
      return undefined;
    }

    // NS_ERROR_NO_INTERFACE exceptions are a special case in browser code,
    // since they're almost always thrown by QueryInterface functions, and
    // handled cleanly by native code.
    if (!isWorker && value == Cr.NS_ERROR_NO_INTERFACE) {
      return undefined;
    }

    // Don't pause on exceptions thrown while inside an evaluation being done on
    // behalf of the client.
    if (this.insideClientEvaluation) {
      return undefined;
    }

    if (this.sourcesManager.isFrameBlackBoxed(youngestFrame)) {
      return undefined;
    }

    // Now that we've decided to pause, ignore this exception if it's thrown by
    // any older frames.
    for (let frame = youngestFrame.older; frame != null; frame = frame.older) {
      this._handledFrameExceptions.set(frame, value);
    }

    try {
      const packet = this._paused(youngestFrame);
      if (!packet) {
        return undefined;
      }

      packet.why = {
        type: PAUSE_REASONS.EXCEPTION,
        exception: this.createValueGrip(value),
      };
      this.emit("paused", packet);

      this._nestedEventLoop.enter();
    } catch (e) {
      reportException("TA_onExceptionUnwind", e);
    }

    return undefined;
  }

  /**
   * A function that the engine calls when a new script has been loaded.
   *
   * @param script Debugger.Script
   *        The source script that has been loaded into a debuggee compartment.
   */
  onNewScript(script) {
    this._addSource(script.source);

    this._maybeTrackFirstStatementBreakpoint(script);
  }

  /**
   * A function called when there's a new source from a thread actor's sources.
   * Emits `newSource` on the thread actor.
   *
   * @param {SourceActor} source
   */
  onNewSourceEvent(source) {
    // When this target is supported by the Watcher Actor,
    // and we listen to SOURCE, we avoid emitting the newSource RDP event
    // as it would be duplicated with the Resource/watchResources API.
    // Could probably be removed once bug 1680280 is fixed.
    if (!this._shouldEmitNewSource) {
      return;
    }

    // Bug 1516197: New sources are likely detected due to either user
    // interaction on the page, or devtools requests sent to the server.
    // We use executeSoon because we don't want to block those operations
    // by sending packets in the middle of them.
    DevToolsUtils.executeSoon(() => {
      if (this.isDestroyed()) {
        return;
      }
      this.emit("newSource", {
        source: source.form(),
      });
    });
  }

  // API used by the Watcher Actor to disable the newSource events
  // Could probably be removed once bug 1680280 is fixed.
  _shouldEmitNewSource = true;
  disableNewSourceEvents() {
    this._shouldEmitNewSource = false;
  }

  /**
   * Filtering function to filter out sources for which we don't want to notify/create
   * source actors
   *
   * @param {Debugger.Source} source
   *        The source to accept or ignore
   * @param Boolean
   *        True, if we want to create a source actor.
   */
  _acceptSource(source) {
    // We have some spurious source created by ExtensionContent.sys.mjs when debugging tabs.
    // These sources are internal stuff injected by WebExt codebase to implement content
    // scripts. We can't easily ignore them from Debugger API, so ignore them
--> --------------------

--> maximum size reached

--> --------------------

quality93%

¤ Dauer der Verarbeitung: 0.100 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.