[DevTools] Typed events and event listeners.

third_party/WebKit/Source/devtools/front_end/common/ObjectBase.js

+/*
+ * Copyright (C) 2008 Apple Inc. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/**
+ * @implements {Common.EventTargetBase}
+ * @unrestricted
+ */
+Common.ObjectBase = class {
+  constructor() {
+    this._listeners = new Map();

[lushnikov, 2016/11/28 19:01:43]

multimap!

+  }
+
+  /**
+   * @template T
+   * @override
+   * @param {function(new:T, ...)} eventType
+   * @param {function(!T)} listener

[pfeldman, 2016/11/28 19:30:38]

I think this exact thing did not work for me in Runtime.js's instance back in
the day.

+   * @param {!Object=} thisObject
+   * @return {!Common.EventTargetBase.EventDescriptor}
+   */
+  addEventListener(eventType, listener, thisObject) {
+    console.assert(listener);
+    if (!this._listeners.has(eventType))
+      this._listeners.set(eventType, []);
+    this._listeners.get(eventType).push({thisObject: thisObject, listener: listener});
+    return new Common.EventTargetBase.EventDescriptor(this, eventType, thisObject, listener);
+  }
+
+  /**
+   * @template T
+   * @override
+   * @param {function(new:T, ...)} eventType
+   * @param {function(!T)} listener
+   * @param {!Object=} thisObject
+   */
+  removeEventListener(eventType, listener, thisObject) {
+    console.assert(listener);
+    if (!this._listeners.has(eventType))
+      return;
+    var listeners = this._listeners.get(eventType);
+    for (var i = 0; i < listeners.length; ++i) {
+      if (listeners[i].listener === listener && listeners[i].thisObject === thisObject)
+        listeners.splice(i--, 1);
+    }
+    if (!listeners.length)
+      this._listeners.delete(eventType);
+  }
+
+  /**
+   * @override
+   */
+  removeAllListeners() {
+    this._listeners.clear();
+  }
+
+  /**
+   * @template T
+   * @override
+   * @param {function(new:T, ...)} eventType
+   * @return {boolean}
+   */
+  hasEventListeners(eventType) {
+    return this._listeners.has(eventType);
+  }
+
+  /**
+   * @template T
+   * @override
+   * @param {T} event
+   */
+  dispatchEventToListeners(event) {
+    var eventType = event.constructor;
+    if (!this._listeners.has(eventType))
+      return;
+    var listeners = this._listeners.get(eventType).slice(0);
+    for (var i = 0; i < listeners.length; ++i)
+      listeners[i].listener.call(listeners[i].thisObject, event);
+  }
+};
+
+/**
+ * @interface
+ */
+Common.EventTargetBase = function() {};
+
+/**
+ * @param {!Array<!Common.EventTargetBase.EventDescriptor>} eventList
+ */
+Common.EventTargetBase.removeEventListeners = function(eventList) {
+  for (var i = 0; i < eventList.length; ++i) {
+    var eventInfo = eventList[i];
+    eventInfo.eventTarget.removeEventListener(eventInfo.eventType, eventInfo.listener, eventInfo.receiver);
+  }
+  // Do not hold references on unused event descriptors.
+  eventList.splice(0, eventList.length);
+};
+
+Common.EventTargetBase.prototype = {
+  /**
+   * @template T
+   * @param {function(new:T, ...)} eventType
+   * @param {function(!T)} listener
+   * @param {!Object=} thisObject
+   * @return {!Common.EventTargetBase.EventDescriptor}
+   */
+  addEventListener(eventType, listener, thisObject) {},
+
+  /**
+   * @template T
+   * @param {function(new:T, ...)} eventType
+   * @param {function(!T)} listener
+   * @param {!Object=} thisObject
+   */
+  removeEventListener(eventType, listener, thisObject) {},
+
+  removeAllListeners() {},
+
+  /**
+   * @template T
+   * @param {function(new:T, ...)} eventType
+   * @return {boolean}
+   */
+  hasEventListeners(eventType) {},
+
+  /**
+   * @template T
+   * @param {T} event
+   */
+  dispatchEventToListeners(event) {},
+};
+
+/**
+ * @template T
+ * @unrestricted
+ */
+Common.EventTargetBase.EventDescriptor = class {
+  /**
+   * @param {!Common.EventTargetBase} eventTarget
+   * @param {function(new:T, ...)} eventType
+   * @param {(!Object|undefined)} receiver
+   * @param {function(!T)} listener
+   */
+  constructor(eventTarget, eventType, receiver, listener) {
+    this.eventTarget = eventTarget;
+    this.eventType = eventType;
+    this.receiver = receiver;
+    this.listener = listener;
+  }
+};