import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

devtools/client/performance/test/helpers/event-utils.js

@@ -0,0 +1,114 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+/* globals dump */
+
+const Services = require("Services");
+
+const KNOWN_EE_APIS = [
+  ["on", "off"],
+  ["addEventListener", "removeEventListener"],
+  ["addListener", "removeListener"]
+];
+
+/**
+ * Listens for any event for a single time on a target, no matter what kind of
+ * event emitter it is, returning a promise resolved with the passed arguments
+ * once the event is fired.
+ */
+exports.once = function (target, eventName, options = {}) {
+  return exports.times(target, eventName, 1, options);
+};
+
+/**
+ * Waits for any event to be fired a specified amount of times on a target, no
+ * matter what kind of event emitter.
+ * Possible options: `useCapture`, `spreadArgs`, `expectedArgs`
+ */
+exports.times = function (target, eventName, receiveCount, options = {}) {
+  let msg = `Waiting for event: '${eventName}' on ${target} for ${receiveCount} time(s)`;
+  if ("expectedArgs" in options) {
+    dump(`${msg} with arguments: ${JSON.stringify(options.expectedArgs)}.\n`);
+  } else {
+    dump(`${msg}.\n`);
+  }
+
+  return new Promise((resolve, reject) => {
+    if (typeof eventName != "string") {
+      reject(new Error(`Unexpected event name: ${eventName}.`));
+    }
+
+    let API = KNOWN_EE_APIS.find(([a, r]) => (a in target) && (r in target));
+    if (!API) {
+      reject(new Error("Target is not a supported event listener."));
+      return;
+    }
+
+    let [add, remove] = API;
+
+    target[add](eventName, function onEvent(...args) {
+      if ("expectedArgs" in options) {
+        for (let index of Object.keys(options.expectedArgs)) {
+          if (
+            // Expected argument matches this regexp.
+            (options.expectedArgs[index] instanceof RegExp &&
+             !options.expectedArgs[index].exec(args[index])) ||
+            // Expected argument is not a regexp and equal to the received arg.
+            (!(options.expectedArgs[index] instanceof RegExp) &&
+             options.expectedArgs[index] != args[index])
+          ) {
+            dump(`Ignoring event '${eventName}' with unexpected argument at index ` +
+                 `${index}: ${args[index]}\n`);
+            return;
+          }
+        }
+      }
+      if (--receiveCount > 0) {
+        dump(`Event: '${eventName}' on ${target} needs to be fired ${receiveCount} ` +
+             `more time(s).\n`);
+      } else if (!receiveCount) {
+        dump(`Event: '${eventName}' on ${target} received.\n`);
+        target[remove](eventName, onEvent, options.useCapture);
+        resolve(options.spreadArgs ? args : args[0]);
+      }
+    }, options.useCapture);
+  });
+};
+
+/**
+ * Like `once`, but for observer notifications.
+ */
+exports.observeOnce = function (notificationName, options = {}) {
+  return exports.observeTimes(notificationName, 1, options);
+};
+
+/**
+ * Like `times`, but for observer notifications.
+ * Possible options: `expectedSubject`
+ */
+exports.observeTimes = function (notificationName, receiveCount, options = {}) {
+  dump(`Waiting for notification: '${notificationName}' for ${receiveCount} time(s).\n`);
+
+  return new Promise((resolve, reject) => {
+    if (typeof notificationName != "string") {
+      reject(new Error(`Unexpected notification name: ${notificationName}.`));
+    }
+
+    Services.obs.addObserver(function onObserve(subject, topic, data) {
+      if ("expectedSubject" in options && options.expectedSubject != subject) {
+        dump(`Ignoring notification '${notificationName}' with unexpected subject: ` +
+             `${subject}\n`);
+        return;
+      }
+      if (--receiveCount > 0) {
+        dump(`Notification: '${notificationName}' needs to be fired ${receiveCount} ` +
+             `more time(s).\n`);
+      } else if (!receiveCount) {
+        dump(`Notification: '${notificationName}' received.\n`);
+        Services.obs.removeObserver(onObserve, topic);
+        resolve(data);
+      }
+    }, notificationName, false);
+  });
+};