1 files changed, 75 insertions, 0 deletions
diff --git a/devtools/shared/platform/chrome/stack.js b/devtools/shared/platform/chrome/stack.js
new file mode 100644
index 000000000..abbe54120
--- /dev/null
+++ b/devtools/shared/platform/chrome/stack.js
@@ -0,0 +1,75 @@
+/* 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/. */
+
+// A few wrappers for stack-manipulation.  This version of the module
+// is used in chrome code.
+
+"use strict";
+
+(function (factory) {
+  // This file might be require()d, but might also be loaded via
+  // Cu.import.  Account for the differences here.
+  if (this.module && module.id.indexOf("stack") >= 0) {
+    // require.
+    const {components, Cu} = require("chrome");
+    factory.call(this, components, Cu, exports);
+  } else {
+    // Cu.import.
+    this.isWorker = false;
+    factory.call(this, Components, Components.utils, this);
+    this.EXPORTED_SYMBOLS = ["callFunctionWithAsyncStack", "describeNthCaller",
+                             "getStack"];
+  }
+}).call(this, function (components, Cu, exports) {
+  /**
+   * Return a description of the Nth caller, suitable for logging.
+   *
+   * @param {Number} n the caller to describe
+   * @return {String} a description of the nth caller.
+   */
+  function describeNthCaller(n) {
+    if (isWorker) {
+      return "";
+    }
+
+    let caller = components.stack;
+    // Do one extra iteration to skip this function.
+    while (n >= 0) {
+      --n;
+      caller = caller.caller;
+    }
+
+    let func = caller.name;
+    let file = caller.filename;
+    if (file.includes(" -> ")) {
+      file = caller.filename.split(/ -> /)[1];
+    }
+    let path = file + ":" + caller.lineNumber;
+
+    return func + "() -> " + path;
+  }
+
+  /**
+   * Return a stack object that can be serialized and, when
+   * deserialized, passed to callFunctionWithAsyncStack.
+   */
+  function getStack() {
+    return components.stack.caller;
+  }
+
+  /**
+   * Like Cu.callFunctionWithAsyncStack but handles the isWorker case
+   * -- |Cu| isn't defined in workers.
+   */
+  function callFunctionWithAsyncStack(callee, stack, id) {
+    if (isWorker) {
+      return callee();
+    }
+    return Cu.callFunctionWithAsyncStack(callee, stack, id);
+  }
+
+  exports.callFunctionWithAsyncStack = callFunctionWithAsyncStack;
+  exports.describeNthCaller = describeNthCaller;
+  exports.getStack = getStack;
+});