Bug 1731553 - [remote] Add shared module to handle stack frames. r=webdriver-reviewers,jdescottes

Differential Revision: https://phabricator.services.mozilla.com/D133087

remote/jar.mn

@@ -16,6 +16,7 @@ remote.jar:
   content/shared/Format.jsm (shared/Format.jsm)
   content/shared/Log.jsm (shared/Log.jsm)
   content/shared/RecommendedPreferences.jsm (shared/RecommendedPreferences.jsm)
+  content/shared/Stack.jsm (shared/Stack.jsm)
   content/shared/Sync.jsm (shared/Sync.jsm)
   content/shared/TabManager.jsm (shared/TabManager.jsm)
   content/shared/WebSocketConnection.jsm (shared/WebSocketConnection.jsm)

remote/shared/Stack.jsm

@@ -0,0 +1,77 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const EXPORTED_SYMBOLS = ["getFramesFromStack", "isChromeFrame"];
+
+/**
+ * An object that contains details of a stack frame.
+ *
+ * @typedef {Object} StackFrame
+ * @see nsIStackFrame
+ *
+ * @property {String=} asyncCause
+ *     Type of asynchronous call by which this frame was invoked.
+ * @property {Number} columnNumber
+ *     The column number for this stack frame.
+ * @property {String} filename
+ *     The source URL for this stack frame.
+ * @property {String} function
+ *     SpiderMonkey’s inferred name for this stack frame’s function, or null.
+ * @property {Number} lineNumber
+ *     The line number for this stack frame (starts with 1).
+ * @property {Number} sourceId
+ *     The process-unique internal integer ID of this source.
+ */
+
+/**
+ * Return a list of stack frames from the given stack.
+ *
+ * Convert stack objects to the JSON attributes expected by consumers.
+ *
+ * @param {Object} stack
+ *     The native stack object to process.
+ *
+ * @returns {Array<StackFrame>=}
+ */
+function getFramesFromStack(stack) {
+  if (!stack || (Cu && Cu.isDeadWrapper(stack))) {
+    // If the global from which this error came from has been nuked,
+    // stack is going to be a dead wrapper.
+    return null;
+  }
+
+  const frames = [];
+  while (stack) {
+    frames.push({
+      asyncCause: stack.asyncCause,
+      columnNumber: stack.column,
+      filename: stack.source,
+      functionName: stack.functionDisplayName || "",
+      lineNumber: stack.line,
+      sourceId: stack.sourceId,
+    });
+
+    stack = stack.parent || stack.asyncParent;
+  }
+
+  return frames;
+}
+
+/**
+ * Check if a frame is from chrome scope.
+ *
+ * @param {Object} frame
+ *     The frame to check
+ *
+ * @returns {boolean}
+ *     True, if frame is from chrome scope
+ */
+function isChromeFrame(frame) {
+  return (
+    frame.filename.startsWith("chrome://") ||
+    frame.filename.startsWith("resource://")
+  );
+}

remote/shared/test/xpcshell/test_Stack.js

@@ -0,0 +1,120 @@
+/* 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/. */
+
+const { getFramesFromStack, isChromeFrame } = ChromeUtils.import(
+  "chrome://remote/content/shared/Stack.jsm"
+);
+
+const sourceFrames = [
+  {
+    column: 1,
+    functionDisplayName: "foo",
+    line: 2,
+    source: "cheese",
+    sourceId: 1,
+  },
+  {
+    column: 3,
+    functionDisplayName: null,
+    line: 4,
+    source: "cake",
+    sourceId: 2,
+  },
+  {
+    column: 5,
+    functionDisplayName: "chrome",
+    line: 6,
+    source: "chrome://foo",
+    sourceId: 3,
+  },
+];
+
+const targetFrames = [
+  {
+    columnNumber: 1,
+    functionName: "foo",
+    lineNumber: 2,
+    filename: "cheese",
+    sourceId: 1,
+  },
+  {
+    columnNumber: 3,
+    functionName: "",
+    lineNumber: 4,
+    filename: "cake",
+    sourceId: 2,
+  },
+  {
+    columnNumber: 5,
+    functionName: "chrome",
+    lineNumber: 6,
+    filename: "chrome://foo",
+    sourceId: 3,
+  },
+];
+
+add_task(async function test_getFramesFromStack() {
+  const stack = buildStack(sourceFrames);
+  const frames = getFramesFromStack(stack, { includeChrome: false });
+
+  ok(Array.isArray(frames), "frames is of expected type Array");
+  equal(frames.length, 3, "Got expected amount of frames");
+  checkFrame(frames.at(0), targetFrames.at(0));
+  checkFrame(frames.at(1), targetFrames.at(1));
+  checkFrame(frames.at(2), targetFrames.at(2));
+});
+
+add_task(async function test_getFramesFromStack_asyncStack() {
+  const stack = buildStack(sourceFrames, true);
+  const frames = getFramesFromStack(stack);
+
+  ok(Array.isArray(frames), "frames is of expected type Array");
+  equal(frames.length, 3, "Got expected amount of frames");
+  checkFrame(frames.at(0), targetFrames.at(0));
+  checkFrame(frames.at(1), targetFrames.at(1));
+  checkFrame(frames.at(2), targetFrames.at(2));
+});
+
+add_task(async function test_isChromeFrame() {
+  for (const filename of ["chrome://foo/bar", "resource://foo/bar"]) {
+    ok(isChromeFrame({ filename }), "Frame is of expected chrome scope");
+  }
+
+  for (const filename of ["http://foo.bar", "about:blank"]) {
+    ok(!isChromeFrame({ filename }), "Frame is of expected content scope");
+  }
+});
+
+function buildStack(frames, async = false) {
+  const parent = async ? "asyncParent" : "parent";
+
+  let currentFrame, stack;
+  for (const frame of frames) {
+    if (currentFrame) {
+      currentFrame[parent] = Object.assign({}, frame);
+      currentFrame = currentFrame[parent];
+    } else {
+      stack = Object.assign({}, frame);
+      currentFrame = stack;
+    }
+  }
+
+  return stack;
+}
+
+function checkFrame(frame, expectedFrame) {
+  equal(
+    frame.columnNumber,
+    expectedFrame.columnNumber,
+    "Got expected column number"
+  );
+  equal(
+    frame.functionName,
+    expectedFrame.functionName,
+    "Got expected function name"
+  );
+  equal(frame.lineNumber, expectedFrame.lineNumber, "Got expected line number");
+  equal(frame.filename, expectedFrame.filename, "Got expected filename");
+  equal(frame.sourceId, expectedFrame.sourceId, "Got expected source id");
+}

remote/shared/test/xpcshell/xpcshell.ini

@@ -4,4 +4,5 @@
 
 [test_Format.js]
 [test_RecommendedPreferences.js]
+[test_Stack.js]
 [test_Sync.js]