Source/WebInspectorUI/UserInterface/Object.js

/*
 * Copyright (C) 2008, 2013 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.
 */

/**
 * @constructor
 */
WebInspector.Object = function()
{
}

/**
 * @param {function} constructor
 */
WebInspector.Object.addConstructorFunctions = function(subclassConstructor)
{
    // Copies the relevant functions the subclass constructor.
    for (var property in WebInspector.Object) {
        var value = WebInspector.Object[property];
        if (typeof value !== "function")
            continue;
        if (value === arguments.callee)
            continue;
        subclassConstructor[property] = value;
    }
}

/**
 * @param {string} eventType
 * @param {function(WebInspector.Event)} listener
 * @param {Object=} thisObject
 */
WebInspector.Object.addEventListener = function(eventType, listener, thisObject)
{
    thisObject = thisObject || null;

    console.assert(eventType, "Object.addEventListener: invalid event type ", eventType, "(listener: ", listener, "thisObject: ", thisObject, ")");
    if (!eventType)
        return;

    console.assert(listener, "Object.addEventListener: invalid listener ", listener, "(event type: ", eventType, "thisObject: ", thisObject, ")");
    if (!listener)
        return;

    if (!this._listeners)
        this._listeners = {};

    var listeners = this._listeners[eventType];
    if (!listeners)
        listeners = this._listeners[eventType] = [];

    // Prevent registering multiple times.
    for (var i = 0; i < listeners.length; ++i) {
        if (listeners[i].listener === listener && listeners[i].thisObject === thisObject)
            return;
    }

    listeners.push({thisObject: thisObject, listener: listener});
};

/**
 * @param {string} eventType
 * @param {function(WebInspector.Event)} listener
 * @param {Object=} thisObject
 */
WebInspector.Object.removeEventListener = function(eventType, listener, thisObject)
{
    eventType = eventType || null;
    listener = listener || null;
    thisObject = thisObject || null;

    if (!this._listeners)
        return;

    if (!eventType) {
        for (eventType in this._listeners)
            this.removeEventListener(eventType, listener, thisObject);
        return;
    }

    var listeners = this._listeners[eventType];
    if (!listeners)
        return;

    for (var i = listeners.length - 1; i >= 0; --i) {
        if (listener && listeners[i].listener === listener && listeners[i].thisObject === thisObject)
            listeners.splice(i, 1);
        else if (!listener && thisObject && listeners[i].thisObject === thisObject)
            listeners.splice(i, 1);
    }

    if (!listeners.length)
        delete this._listeners[eventType];

    if (!Object.keys(this._listeners).length)
        delete this._listeners;
};

WebInspector.Object.removeAllListeners = function()
{
    delete this._listeners;
};

/**
 * @param {string} eventType
 * @return {boolean}
 */
WebInspector.Object.hasEventListeners = function(eventType)
{
    if (!this._listeners || !this._listeners[eventType])
        return false;
    return true;
};

WebInspector.Object.prototype = {
    constructor: WebInspector.Object,

    /**
     * @param {string} eventType
     * @param {function(WebInspector.Event)} listener
     * @param {Object=} thisObject
     */
    addEventListener: WebInspector.Object.addEventListener,

    /**
     * @param {string} eventType
     * @param {function(WebInspector.Event)} listener
     * @param {Object=} thisObject
     */
    removeEventListener: WebInspector.Object.removeEventListener,

    removeAllListeners: WebInspector.Object.removeAllListeners,

    /**
     * @param {string} eventType
     * @return {boolean}
     */
    hasEventListeners: WebInspector.Object.hasEventListeners,

    /**
     * @param {string} eventType
     * @param {*=} eventData
     * @return {boolean}
     */
    dispatchEventToListeners: function(eventType, eventData)
    {
        var event = new WebInspector.Event(this, eventType, eventData);

        function dispatch(object)
        {
            if (!object || !object._listeners || !object._listeners[eventType] || event._stoppedPropagation)
                return;

            // Make a copy with slice so mutations during the loop doesn't affect us.
            var listenersForThisEvent = object._listeners[eventType].slice(0);

            // Iterate over the listeners and call them. Stop if stopPropagation is called.
            for (var i = 0; i < listenersForThisEvent.length; ++i) {
                listenersForThisEvent[i].listener.call(listenersForThisEvent[i].thisObject, event);
                if (event._stoppedPropagation)
                    break;
            }
        }

        // Dispatch to listeners of this specific object.
        dispatch(this);

        // Allow propagation again so listeners on the constructor always have a crack at the event.
        event._stoppedPropagation = false;

        // Dispatch to listeners on all constructors up the prototype chain, including the immediate constructor.
        var constructor = this.constructor;
        while (constructor) {
            dispatch(constructor);

            if (!constructor.prototype.__proto__)
                break;

            constructor = constructor.prototype.__proto__.constructor;
        }

        return event.defaultPrevented;
    }
}

/**
 * @constructor
 * @param {WebInspector.Object} target
 * @param {string} type
 * @param {*=} data
 */
WebInspector.Event = function(target, type, data)
{
    this.target = target;
    this.type = type;
    this.data = data;
    this.defaultPrevented = false;
    this._stoppedPropagation = false;
}

WebInspector.Event.prototype = {
    constructor: WebInspector.Event,

    stopPropagation: function()
    {
        this._stoppedPropagation = true;
    },

    preventDefault: function()
    {
        this.defaultPrevented = true;
    }
}

WebInspector.notifications = new WebInspector.Object;