import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

testing/mochitest/tests/SimpleTest/SpawnTask.js

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+// # SpawnTask.js
+// Directly copied from the "co" library by TJ Holowaychuk.
+// See https://github.com/tj/co/tree/4.6.0
+// For use with mochitest-plain and mochitest-chrome.
+
+// spawn_task(generatorFunction):
+// Expose only the `co` function, which is very similar to Task.spawn in Task.jsm.
+// We call this function spawn_task to make its purpose more plain, and to
+// reduce the chance of name collisions.
+var spawn_task = (function () {
+
+/**
+ * slice() reference.
+ */
+
+var slice = Array.prototype.slice;
+
+/**
+ * Wrap the given generator `fn` into a
+ * function that returns a promise.
+ * This is a separate function so that
+ * every `co()` call doesn't create a new,
+ * unnecessary closure.
+ *
+ * @param {GeneratorFunction} fn
+ * @return {Function}
+ * @api public
+ */
+
+co.wrap = function (fn) {
+  createPromise.__generatorFunction__ = fn;
+  return createPromise;
+  function createPromise() {
+    return co.call(this, fn.apply(this, arguments));
+  }
+};
+
+/**
+ * Execute the generator function or a generator
+ * and return a promise.
+ *
+ * @param {Function} fn
+ * @return {Promise}
+ * @api public
+ */
+
+function co(gen) {
+  var ctx = this;
+  var args = slice.call(arguments, 1)
+
+  // we wrap everything in a promise to avoid promise chaining,
+  // which leads to memory leak errors.
+  // see https://github.com/tj/co/issues/180
+  return new Promise(function(resolve, reject) {
+    if (typeof gen === 'function') gen = gen.apply(ctx, args);
+    if (!gen || typeof gen.next !== 'function') return resolve(gen);
+
+    onFulfilled();
+
+    /**
+     * @param {Mixed} res
+     * @return {Promise}
+     * @api private
+     */
+
+    function onFulfilled(res) {
+      var ret;
+      try {
+        ret = gen.next(res);
+      } catch (e) {
+        return reject(e);
+      }
+      next(ret);
+    }
+
+    /**
+     * @param {Error} err
+     * @return {Promise}
+     * @api private
+     */
+
+    function onRejected(err) {
+      var ret;
+      try {
+        ret = gen.throw(err);
+      } catch (e) {
+        return reject(e);
+      }
+      next(ret);
+    }
+
+    /**
+     * Get the next value in the generator,
+     * return a promise.
+     *
+     * @param {Object} ret
+     * @return {Promise}
+     * @api private
+     */
+
+    function next(ret) {
+      if (ret.done) return resolve(ret.value);
+      var value = toPromise.call(ctx, ret.value);
+      if (value && isPromise(value)) return value.then(onFulfilled, onRejected);
+      return onRejected(new TypeError('You may only yield a function, promise, generator, array, or object, '
+        + 'but the following object was passed: "' + String(ret.value) + '"'));
+    }
+  });
+}
+
+/**
+ * Convert a `yield`ed value into a promise.
+ *
+ * @param {Mixed} obj
+ * @return {Promise}
+ * @api private
+ */
+
+function toPromise(obj) {
+  if (!obj) return obj;
+  if (isPromise(obj)) return obj;
+  if (isGeneratorFunction(obj) || isGenerator(obj)) return co.call(this, obj);
+  if ('function' == typeof obj) return thunkToPromise.call(this, obj);
+  if (Array.isArray(obj)) return arrayToPromise.call(this, obj);
+  if (isObject(obj)) return objectToPromise.call(this, obj);
+  return obj;
+}
+
+/**
+ * Convert a thunk to a promise.
+ *
+ * @param {Function}
+ * @return {Promise}
+ * @api private
+ */
+
+function thunkToPromise(fn) {
+  var ctx = this;
+  return new Promise(function (resolve, reject) {
+    fn.call(ctx, function (err, res) {
+      if (err) return reject(err);
+      if (arguments.length > 2) res = slice.call(arguments, 1);
+      resolve(res);
+    });
+  });
+}
+
+/**
+ * Convert an array of "yieldables" to a promise.
+ * Uses `Promise.all()` internally.
+ *
+ * @param {Array} obj
+ * @return {Promise}
+ * @api private
+ */
+
+function arrayToPromise(obj) {
+  return Promise.all(obj.map(toPromise, this));
+}
+
+/**
+ * Convert an object of "yieldables" to a promise.
+ * Uses `Promise.all()` internally.
+ *
+ * @param {Object} obj
+ * @return {Promise}
+ * @api private
+ */
+
+function objectToPromise(obj){
+  var results = new obj.constructor();
+  var keys = Object.keys(obj);
+  var promises = [];
+  for (var i = 0; i < keys.length; i++) {
+    var key = keys[i];
+    var promise = toPromise.call(this, obj[key]);
+    if (promise && isPromise(promise)) defer(promise, key);
+    else results[key] = obj[key];
+  }
+  return Promise.all(promises).then(function () {
+    return results;
+  });
+
+  function defer(promise, key) {
+    // predefine the key in the result
+    results[key] = undefined;
+    promises.push(promise.then(function (res) {
+      results[key] = res;
+    }));
+  }
+}
+
+/**
+ * Check if `obj` is a promise.
+ *
+ * @param {Object} obj
+ * @return {Boolean}
+ * @api private
+ */
+
+function isPromise(obj) {
+  return 'function' == typeof obj.then;
+}
+
+/**
+ * Check if `obj` is a generator.
+ *
+ * @param {Mixed} obj
+ * @return {Boolean}
+ * @api private
+ */
+
+function isGenerator(obj) {
+  return 'function' == typeof obj.next && 'function' == typeof obj.throw;
+}
+
+/**
+ * Check if `obj` is a generator function.
+ *
+ * @param {Mixed} obj
+ * @return {Boolean}
+ * @api private
+ */
+function isGeneratorFunction(obj) {
+  var constructor = obj.constructor;
+  if (!constructor) return false;
+  if ('GeneratorFunction' === constructor.name || 'GeneratorFunction' === constructor.displayName) return true;
+  return isGenerator(constructor.prototype);
+}
+
+/**
+ * Check for plain object.
+ *
+ * @param {Mixed} val
+ * @return {Boolean}
+ * @api private
+ */
+
+function isObject(val) {
+  return Object == val.constructor;
+}
+
+return co;
+})();
+
+// add_task(generatorFunction):
+// Call `add_task(generatorFunction)` for each separate
+// asynchronous task in a mochitest. Tasks are run consecutively.
+// Before the first task, `SimpleTest.waitForExplicitFinish()`
+// will be called automatically, and after the last task,
+// `SimpleTest.finish()` will be called.
+var add_task = (function () {
+  // The list of tasks to run.
+  var task_list = [];
+  // The "add_task" function
+  return function (generatorFunction) {
+    if (task_list.length === 0) {
+      // This is the first time add_task has been called.
+      // First, confirm that SimpleTest is available.
+      if (!SimpleTest) {
+        throw new Error("SimpleTest not available.");
+      }
+      // Don't stop tests until asynchronous tasks are finished.
+      SimpleTest.waitForExplicitFinish();
+      // Because the client is using add_task for this set of tests,
+      // we need to spawn a "master task" that calls each task in succesion.
+      // Use setTimeout to ensure the master task runs after the client
+      // script finishes.
+      setTimeout(function () {
+        spawn_task(function* () {
+          // We stop the entire test file at the first exception because this
+          // may mean that the state of subsequent tests may be corrupt.
+          try {
+            for (var task of task_list) {
+              var name = task.name || "";
+              info("SpawnTask.js | Entering test " + name);
+              yield task();
+              info("SpawnTask.js | Leaving test " + name);
+            }
+          } catch (ex) {
+            try {
+              ok(false, "" + ex);
+            } catch (ex2) {
+              ok(false, "(The exception cannot be converted to string.)");
+            }
+          }
+          // All tasks are finished.
+          SimpleTest.finish();
+        });
+      });
+    }
+    // Add the task to the list of tasks to run after
+    // the main thread is finished.
+    task_list.push(generatorFunction);
+  };
+})();