Bug 1514248 - Reimplement xpcshell test debugging using a public thread-actor API. r=jlast

Differential Revision: https://phabricator.services.mozilla.com/D14561

--HG--
extra : moz-landing-system : lando

devtools/server/actors/source.js

@@ -563,8 +563,8 @@ const SourceActor = ActorClassWithSpec(sourceSpec, {
    *          A promise that resolves to a JSON object representing the
    *          response.
    */
-  setBreakpoint: function(line, column, condition, noSliding) {
-    if (this.threadActor.state !== "paused") {
+  setBreakpoint: function(line, column, condition, noSliding, inNestedLoop) {
+    if (!inNestedLoop && this.threadActor.state !== "paused") {
       const errorObject = {
         error: "wrongState",
         message: "Cannot set breakpoint while debuggee is running.",

devtools/server/actors/thread.js

@@ -80,6 +80,10 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
     // server.
     this._hiddenBreakpoints = new Map();
 
+    // A Set of URLs string to watch for when new sources are found by
+    // the debugger instance.
+    this._onLoadBreakpointURLs = new Set();
+
     this.global = global;
 
     this._allEventsListener = this._allEventsListener.bind(this);
@@ -96,9 +100,12 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
     this._onOpeningRequest = this._onOpeningRequest.bind(this);
     EventEmitter.on(this._parent, "window-ready", this._onWindowReady);
 
-    // Set a wrappedJSObject property so |this| can be sent via the observer svc
-    // for the xpcshell harness.
-    this.wrappedJSObject = this;
+    if (Services.obs) {
+      // Set a wrappedJSObject property so |this| can be sent via the observer svc
+      // for the xpcshell harness.
+      this.wrappedJSObject = this;
+      Services.obs.notifyObservers(this, "devtools-thread-instantiated");
+    }
   },
 
   // Used by the ObjectActor to keep track of the depth of grip() calls.
@@ -306,6 +313,17 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
     }
   },
 
+  /**
+   * 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);
@@ -2017,6 +2035,12 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
       }
     }
 
+    if (this._onLoadBreakpointURLs.has(source.url)) {
+      this.unsafeSynchronize(
+        sourceActor.setBreakpoint(1, undefined, undefined, undefined, true)
+      );
+    }
+
     this._debuggerSourcesSeen.add(source);
     return true;
   },

testing/xpcshell/head.js

@@ -397,7 +397,6 @@ function _setupDebuggerServer(breakpointFiles, callback) {
                     "See also https://bugzil.la/1215378.");
   }
   let { DebuggerServer } = require("devtools/server/main");
-  let { OriginalLocation } = require("devtools/server/actors/common");
   DebuggerServer.init();
   DebuggerServer.registerAllActors();
   let { createRootActor } = require("resource://testing-common/dbg-actors.js");
@@ -406,29 +405,14 @@ function _setupDebuggerServer(breakpointFiles, callback) {
 
   // An observer notification that tells us when we can "resume" script
   // execution.
-  const TOPICS = ["devtools-thread-resumed", "xpcshell-test-devtools-shutdown"];
+  const TOPICS = ["devtools-thread-instantiated", "devtools-thread-resumed", "xpcshell-test-devtools-shutdown"];
   let observe = function(subject, topic, data) {
-    switch (topic) {
-      case "devtools-thread-resumed":
-        // Exceptions in here aren't reported and block the debugger from
-        // resuming, so...
-        try {
-          // Add a breakpoint for the first line in our test files.
-          let threadActor = subject.wrappedJSObject;
-          for (let file of breakpointFiles) {
-            // Pass an empty `source` object to workaround `source` function assertion
-            let sourceActor = threadActor.sources.source({originalUrl: file, source: {}});
-            sourceActor._getOrCreateBreakpointActor(new OriginalLocation(sourceActor, 1));
-          }
-        } catch (ex) {
-          info("Failed to initialize breakpoints: " + ex + "\n" + ex.stack);
-        }
-        break;
-      case "xpcshell-test-devtools-shutdown":
-        // the debugger has shutdown before we got a resume event - nothing
-        // special to do here.
-        break;
+    if (topic === "devtools-thread-instantiated") {
+      const threadActor = subject.wrappedJSObject;
+      threadActor.setBreakpointOnLoad(breakpointFiles);
+      return;
     }
+
     for (let topicToRemove of TOPICS) {
       _Services.obs.removeObserver(observe, topicToRemove);
     }