Simplify QWebChannel usage by merging webchannel.js and qobject.js.

The code now resides in a single qwebchannel.js file and there is only
a single callback-nesting required to setup a MetaObjectPublisher
connection.

The server-side will be simplified in the next step.

Change-Id: Ib5fc77a03c2b281c61af91713411eed571ec6108
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 397 insertions, 0 deletions

diff --git a/src/webchannel/qwebchannel.js b/src/webchannel/qwebchannel.js
new file mode 100644
index 0000000..fe3c650
--- /dev/null
+++ b/src/webchannel/qwebchannel.js
@@ -0,0 +1,397 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2013 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+** Contact: http://www.qt-project.org/legal
+*
+** This file is part of the QtWebChannel module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+"use strict";
+
+var QWebChannel = function(baseUrl, initCallback, rawChannel)
+{
+    var channel = this;
+    // support multiple channels listening to the same socket
+    // the responses to channel.exec must be distinguishable
+    // see: http://stackoverflow.com/a/2117523/35250
+    this.id = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
+        var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
+        return v.toString(16);
+    });
+    ///TODO: use ssl?
+    var socketUrl = "ws://" + baseUrl;
+    this.socket = new WebSocket(socketUrl, "QWebChannel");
+    this.send = function(data)
+    {
+        if (typeof(data) !== "string") {
+            data = JSON.stringify(data);
+        }
+        channel.socket.send(data);
+    };
+
+    this.socket.onopen = function()
+    {
+        if (rawChannel) {
+            initCallback(channel);
+        } else {
+            channel.initMetaObjectPublisher(initCallback);
+        }
+    };
+    this.socket.onclose = function()
+    {
+        console.error("web channel closed");
+    };
+    this.socket.onerror = function(error)
+    {
+        console.error("web channel error: " + error);
+    };
+    this.socket.onmessage = function(message)
+    {
+        var jsonData = JSON.parse(message.data);
+        if (jsonData.id === undefined) {
+            console.error("invalid message received:", message.data);
+            return;
+        }
+        if (jsonData.data === undefined) {
+            jsonData.data = {};
+        }
+        if (jsonData.response) {
+            if (jsonData.id[0] === channel.id) {
+                channel.execCallbacks[jsonData.id[1]](jsonData.data);
+                delete channel.execCallbacks[jsonData.id];
+            }
+        } else if (channel.subscriptions[jsonData.id]) {
+            channel.subscriptions[jsonData.id].forEach(function(callback) {
+                (callback)(jsonData.data); }
+            );
+        }
+    };
+
+    this.subscriptions = {};
+    this.subscribe = function(id, callback)
+    {
+        if (channel.subscriptions[id]) {
+            channel.subscriptions[id].push(callback);
+        } else {
+            channel.subscriptions[id] = [callback];
+        }
+    };
+
+    this.execCallbacks = {};
+    this.execId = 0;
+    this.exec = function(data, callback)
+    {
+        if (!callback) {
+            // if no callback is given, send directly
+            channel.send({data: data});
+            return;
+        }
+        if (channel.execId === Number.MAX_VALUE) {
+            // wrap
+            channel.execId = Number.MIN_VALUE;
+        }
+        var id = channel.execId++;
+        channel.execCallbacks[id] = callback;
+        channel.send({"id": [channel.id, id], "data": data});
+    };
+
+    this.objectMap = {};
+
+    this.initMetaObjectPublisher = function(doneCallback)
+    {
+        // prevent multiple initialization which might happen with multiple webchannel clients.
+        var initialized = false;
+
+        console.log(channel);
+        channel.subscribe(
+            "Qt.signal",
+            function(payload) {
+                var object = window[payload.object] || channel.objectMap[payload.object];
+                if (object) {
+                    object.signalEmitted(payload.signal, payload.args);
+                } else {
+                    console.warn("Unhandled signal: " + payload.object + "::" + payload.signal);
+                }
+            }
+        );
+
+        channel.subscribe(
+            "Qt.propertyUpdate",
+            function(payload) {
+                for (var i in payload) {
+                    var data = payload[i];
+                    var object = window[data.object] || channel.objectMap[data.object];
+                    if (object) {
+                        object.propertyUpdate(data.signals, data.properties);
+                    } else {
+                        console.warn("Unhandled property update: " + data.object + "::" + data.signal);
+                    }
+                }
+                setTimeout(function() { channel.exec({type: "Qt.idle"}); }, 0);
+            }
+        );
+
+        channel.subscribe(
+            "Qt.init",
+            function(payload) {
+                if (initialized) {
+                    return;
+                }
+                initialized = true;
+                for (var objectName in payload) {
+                    var data = payload[objectName];
+                    var object = new QObject(objectName, data, channel);
+                    window[objectName] = object;
+                }
+                if (doneCallback) {
+                    doneCallback(channel);
+                }
+                setTimeout(function() { channel.exec({type: "Qt.idle"}); }, 0);
+            }
+        );
+
+        channel.debug = function(message)
+        {
+            channel.send({"data" : {"type" : "Qt.Debug", "message" : message}});
+        };
+
+        channel.exec({type:"Qt.init"});
+    }
+};
+
+function QObject(name, data, webChannel)
+{
+    this.__id__ = name;
+    webChannel.objectMap[name] = this;
+
+    // List of callbacks that get invoked upon signal emission
+    this.__objectSignals__ = {};
+
+    // Cache of all properties, updated when a notify signal is emitted
+    this.__propertyCache__ = {};
+
+    var object = this;
+
+    // ----------------------------------------------------------------------
+
+    function unwrapQObject( response )
+    {
+        if (!response["__QObject*__"]
+            || response["id"] === undefined
+            || response["data"] === undefined) {
+            return response;
+        }
+        var objectId = response.id;
+        if (webChannel.objectMap[objectId])
+            return webChannel.objectMap[objectId];
+
+        var qObject = new QObject( objectId, response.data, webChannel );
+        qObject.destroyed.connect(function() {
+            if (webChannel.objectMap[objectId] === qObject) {
+                delete webChannel.objectMap[objectId];
+                // reset the now deleted QObject to an empty {} object
+                // just assigning {} though would not have the desired effect, but the
+                // below also ensures all external references will see the empty map
+                for (var prop in qObject) {
+                    delete qObject[prop];
+                }
+            }
+        });
+        return qObject;
+    }
+
+    function addSignal(signalData, isPropertyNotifySignal)
+    {
+        var signalName = signalData[0];
+        var signalIndex = signalData[1];
+        object[signalName] = {
+            connect: function(callback) {
+                if (typeof(callback) !== "function") {
+                    console.error("Bad callback given to connect to signal " + signalName);
+                    return;
+                }
+
+                object.__objectSignals__[signalIndex] = object.__objectSignals__[signalIndex] || [];
+                object.__objectSignals__[signalIndex].push(callback);
+
+                if (!isPropertyNotifySignal) {
+                    // only required for "pure" signals, handled separately for properties in propertyUpdate
+                    webChannel.exec({
+                        type: "Qt.connectToSignal",
+                        object: object.__id__,
+                        signal: signalIndex
+                    });
+                }
+            },
+            disconnect: function(callback) {
+                if (typeof(callback) !== "function") {
+                    console.error("Bad callback given to disconnect from signal " + signalName);
+                    return;
+                }
+                object.__objectSignals__[signalIndex] = object.__objectSignals__[signalIndex] || [];
+                var idx = object.__objectSignals__[signalIndex].indexOf(callback);
+                if (idx === -1) {
+                    console.error("Cannot find connection of signal " + signalName + " to " + callback.name);
+                    return;
+                }
+                object.__objectSignals__[signalIndex].splice(idx, 1);
+                if (!isPropertyNotifySignal && object.__objectSignals__[signalIndex].length === 0) {
+                    // only required for "pure" signals, handled separately for properties in propertyUpdate
+                    webChannel.exec({
+                        type: "Qt.disconnectFromSignal",
+                        object: object.__id__,
+                        signal: signalIndex
+                    });
+                }
+            }
+        };
+    }
+
+    /**
+     * Invokes all callbacks for the given signalname. Also works for property notify callbacks.
+     */
+    function invokeSignalCallbacks(signalName, signalArgs)
+    {
+        var connections = object.__objectSignals__[signalName];
+        if (connections) {
+            connections.forEach(function(callback) {
+                callback.apply(callback, signalArgs);
+            });
+        }
+    }
+
+    this.propertyUpdate = function(signals, propertyMap)
+    {
+        // update property cache
+        for (var propertyIndex in propertyMap) {
+            var propertyValue = propertyMap[propertyIndex];
+            object.__propertyCache__[propertyIndex] = propertyValue;
+        }
+
+        for (var signalName in signals) {
+            // Invoke all callbacks, as signalEmitted() does not. This ensures the
+            // property cache is updated before the callbacks are invoked.
+            invokeSignalCallbacks(signalName, signals[signalName]);
+        }
+    }
+
+    this.signalEmitted = function(signalName, signalArgs)
+    {
+        invokeSignalCallbacks(signalName, signalArgs);
+    }
+
+    function addMethod(methodData)
+    {
+        var methodName = methodData[0];
+        var methodIdx = methodData[1];
+        object[methodName] = function() {
+            var args = [];
+            var callback;
+            for (var i = 0; i < arguments.length; ++i) {
+                if (typeof arguments[i] === "function")
+                    callback = arguments[i];
+                else
+                    args.push(arguments[i]);
+            }
+
+            webChannel.exec({"type": "Qt.invokeMethod", "object": object.__id__, "method": methodIdx, "args": args}, function(response) {
+                if ( (response !== undefined) && callback ) {
+                    (callback)(unwrapQObject(response));
+                }
+            });
+        };
+    }
+
+    function bindGetterSetter(propertyInfo)
+    {
+        var propertyIndex = propertyInfo[0];
+        var propertyName = propertyInfo[1];
+        var notifySignalData = propertyInfo[2];
+        // initialize property cache with current value
+        object.__propertyCache__[propertyIndex] = propertyInfo[3];
+
+        if (notifySignalData) {
+            if (notifySignalData[0] === 1) {
+                // signal name is optimized away, reconstruct the actual name
+                notifySignalData[0] = propertyName + "Changed";
+            }
+            addSignal(notifySignalData, true);
+        }
+
+        object.__defineSetter__(propertyName, function(value) {
+            if (value === undefined) {
+                console.warn("Property setter for " + propertyName + " called with undefined value!");
+                return;
+            }
+            object.__propertyCache__[propertyIndex] = value;
+            webChannel.exec({"type": "Qt.setProperty", "object": object.__id__, "property": propertyIndex, "value": value });
+
+        });
+        object.__defineGetter__(propertyName, function () {
+            return (function (callback) {
+                var propertyValue = object.__propertyCache__[propertyIndex];
+                if (propertyValue === undefined) {
+                    // This shouldn't happen
+                    console.warn("Undefined value in property cache for property \"" + propertyName + "\" in object " + object.__id__);
+                }
+
+                // TODO: A callback is not required here anymore, but is kept for backwards compatibility
+                if (callback !== undefined) {
+                    if (typeof(callback) !== "function") {
+                        console.error("Bad callback given to get property " + property);
+                        return;
+                    }
+                    callback(propertyValue);
+                } else {
+                    return propertyValue;
+                }
+            });
+        });
+    }
+
+    // ----------------------------------------------------------------------
+
+    data.methods.forEach(addMethod);
+
+    data.properties.forEach(bindGetterSetter);
+
+    data.signals.forEach(function(signal) { addSignal(signal, false); });
+
+    for (var name in data.enums) {
+        object[name] = data.enums[name];
+    }
+}