Fix example source installation and location of qwebchannel.jsHEADdev

Adds all example dirs with qt_internal_add_example() so that their
source code will be installed when QT_INSTALL_EXAMPLES_SOURCES is set.

Also puts qwebchannel.js into a proper location at src/webchannel and
removes it from the examples/ tree. Adds a CMake file that will find
qwebchannel.js.

Tested configurations (CMake only):
* Out-of-source build, examples built normally
* Out-of-source build, examples built as ExternalProject
* Examples built standalone

Change-Id: Iac80602203676399a730ac4816c38bd0068e9570
Reviewed-by: Alexandru Croitor <[email protected]>

3 files changed, 491 insertions, 6 deletions

diff --git a/src/webchannel/CMakeLists.txt b/src/webchannel/CMakeLists.txt
index 54a7457..83ae035 100644
--- a/src/webchannel/CMakeLists.txt
+++ b/src/webchannel/CMakeLists.txt
@@ -1,6 +1,26 @@
 # Copyright (C) 2022 The Qt Company Ltd.
 # SPDX-License-Identifier: BSD-3-Clause
 
+if(QT6_INSTALL_QT_SHAREDIR)
+  set(INSTALL_WEBCHANNEL_SHAREDIR "${QT6_INSTALL_QT_SHAREDIR}/webchannel")
+else()
+  set(INSTALL_WEBCHANNEL_SHAREDIR "${INSTALL_QT_SHAREDIR}/webchannel")
+endif()
+
+include(CMakePackageConfigHelpers)
+
+set(target "WebChannel")
+set(path_suffix "${INSTALL_CMAKE_NAMESPACE}${target}")
+qt_path_join(config_build_dir ${QT_CONFIG_BUILD_DIR} ${path_suffix})
+qt_path_join(config_install_dir ${QT_CONFIG_INSTALL_DIR} ${path_suffix})
+
+configure_package_config_file(
+    Qt6WebChannelExtras.cmake.in
+    "${config_build_dir}/Qt6WebChannelExtras.cmake"
+    INSTALL_DESTINATION "${config_install_dir}"
+    PATH_VARS INSTALL_WEBCHANNEL_SHAREDIR
+)
+
 qt_internal_add_module(WebChannel
     SOURCES
         qmetaobjectpublisher.cpp qmetaobjectpublisher_p.h
@@ -8,22 +28,22 @@ qt_internal_add_module(WebChannel
         qwebchannelabstracttransport.cpp qwebchannelabstracttransport.h
         signalhandler_p.h
         qwebchannelglobal.h
+        qwebchannel.js
     DEFINES
         QT_NO_CONTEXTLESS_CONNECT
     LIBRARIES
         Qt::CorePrivate
-)
-
-set(resource_file "../../examples/webchannel/shared/qwebchannel.js")
-set_source_files_properties(${resource_file} PROPERTIES
-    QT_RESOURCE_ALIAS "qwebchannel.js"
+    EXTRA_CMAKE_FILES
+        "${config_build_dir}/Qt6WebChannelExtras.cmake"
+    EXTRA_CMAKE_INCLUDES
+        Qt6WebChannelExtras.cmake
 )
 
 qt_internal_add_resource(WebChannel "resources"
     PREFIX
         "/qtwebchannel/"
     FILES
-        ${resource_file}
+        qwebchannel.js
 )
 
 if(TARGET Qt::Qml)
@@ -36,3 +56,7 @@ qt_internal_add_docs(WebChannel
     doc/qtwebchannel.qdocconf
 )
 
+install(FILES qwebchannel.js
+        DESTINATION "${INSTALL_WEBCHANNEL_SHAREDIR}")
+file(COPY qwebchannel.js
+     DESTINATION "${QT_BUILD_DIR}/${INSTALL_WEBCHANNEL_SHAREDIR}/")
diff --git a/src/webchannel/Qt6WebChannelExtras.cmake.in b/src/webchannel/Qt6WebChannelExtras.cmake.in
new file mode 100644
index 0000000..0dd171a
--- /dev/null
+++ b/src/webchannel/Qt6WebChannelExtras.cmake.in
@@ -0,0 +1,6 @@
+# Copyright (C) 2025 Menlo Systems GmbH; author Arno Rehn <[email protected]>
+# SPDX-License-Identifier: BSD-3-Clause
+
+@PACKAGE_INIT@
+
+set(QT_QWEBCHANNEL_JS_PATH "@PACKAGE_INSTALL_WEBCHANNEL_SHAREDIR@/qwebchannel.js")
diff --git a/src/webchannel/qwebchannel.js b/src/webchannel/qwebchannel.js
new file mode 100644
index 0000000..56fa66a
--- /dev/null
+++ b/src/webchannel/qwebchannel.js
@@ -0,0 +1,455 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// Copyright (C) 2016 Klarälvdalens Datakonsult AB, a KDAB Group company, [email protected], author Milian Wolff <[email protected]>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+"use strict";
+
+var QWebChannelMessageTypes = {
+    signal: 1,
+    propertyUpdate: 2,
+    init: 3,
+    idle: 4,
+    debug: 5,
+    invokeMethod: 6,
+    connectToSignal: 7,
+    disconnectFromSignal: 8,
+    setProperty: 9,
+    response: 10,
+};
+
+var QWebChannel = function(transport, initCallback, converters)
+{
+    if (typeof transport !== "object" || typeof transport.send !== "function") {
+        console.error("The QWebChannel expects a transport object with a send function and onmessage callback property." +
+                      " Given is: transport: " + typeof(transport) + ", transport.send: " + typeof(transport.send));
+        return;
+    }
+
+    var channel = this;
+    this.transport = transport;
+
+    var converterRegistry =
+    {
+        Date : function(response) {
+            if (typeof response === "string"
+                && response.match(
+                        /^-?\d+-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d*)?([-+\u2212](\d{2}):(\d{2})|Z)?$/)) {
+                var date = new Date(response);
+                if (!isNaN(date))
+                    return date;
+            }
+            return undefined; // Return undefined if current converter is not applicable
+        }
+    };
+
+    this.usedConverters = [];
+
+    this.addConverter = function(converter)
+    {
+        if (typeof converter === "string") {
+            if (converterRegistry.hasOwnProperty(converter))
+                this.usedConverters.push(converterRegistry[converter]);
+            else
+                console.error("Converter '" + converter + "' not found");
+        } else if (typeof converter === "function") {
+            this.usedConverters.push(converter);
+        } else {
+            console.error("Invalid converter object type " + typeof converter);
+        }
+    }
+
+    if (Array.isArray(converters)) {
+        for (const converter of converters)
+            this.addConverter(converter);
+    } else if (converters !== undefined) {
+        this.addConverter(converters);
+    }
+
+    this.send = function(data)
+    {
+        if (typeof(data) !== "string") {
+            data = JSON.stringify(data);
+        }
+        channel.transport.send(data);
+    }
+
+    this.transport.onmessage = function(message)
+    {
+        var data = message.data;
+        if (typeof data === "string") {
+            data = JSON.parse(data);
+        }
+        switch (data.type) {
+            case QWebChannelMessageTypes.signal:
+                channel.handleSignal(data);
+                break;
+            case QWebChannelMessageTypes.response:
+                channel.handleResponse(data);
+                break;
+            case QWebChannelMessageTypes.propertyUpdate:
+                channel.handlePropertyUpdate(data);
+                break;
+            default:
+                console.error("invalid message received:", message.data);
+                break;
+        }
+    }
+
+    this.execCallbacks = {};
+    this.execId = 0;
+    this.exec = function(data, callback)
+    {
+        if (!callback) {
+            // if no callback is given, send directly
+            channel.send(data);
+            return;
+        }
+        if (channel.execId === Number.MAX_VALUE) {
+            // wrap
+            channel.execId = Number.MIN_VALUE;
+        }
+        if (data.hasOwnProperty("id")) {
+            console.error("Cannot exec message with property id: " + JSON.stringify(data));
+            return;
+        }
+        data.id = channel.execId++;
+        channel.execCallbacks[data.id] = callback;
+        channel.send(data);
+    };
+
+    this.objects = {};
+
+    this.handleSignal = function(message)
+    {
+        var object = channel.objects[message.object];
+        if (object) {
+            object.signalEmitted(message.signal, message.args);
+        } else {
+            console.warn("Unhandled signal: " + message.object + "::" + message.signal);
+        }
+    }
+
+    this.handleResponse = function(message)
+    {
+        if (!message.hasOwnProperty("id")) {
+            console.error("Invalid response message received: ", JSON.stringify(message));
+            return;
+        }
+        channel.execCallbacks[message.id](message.data);
+        delete channel.execCallbacks[message.id];
+    }
+
+    this.handlePropertyUpdate = function(message)
+    {
+        message.data.forEach(data => {
+            var object = channel.objects[data.object];
+            if (object) {
+                object.propertyUpdate(data.signals, data.properties);
+            } else {
+                console.warn("Unhandled property update: " + data.object + "::" + data.signal);
+            }
+        });
+        channel.exec({type: QWebChannelMessageTypes.idle});
+    }
+
+    this.debug = function(message)
+    {
+        channel.send({type: QWebChannelMessageTypes.debug, data: message});
+    };
+
+    channel.exec({type: QWebChannelMessageTypes.init}, function(data) {
+        for (const objectName of Object.keys(data)) {
+            new QObject(objectName, data[objectName], channel);
+        }
+
+        // now unwrap properties, which might reference other registered objects
+        for (const objectName of Object.keys(channel.objects)) {
+            channel.objects[objectName].unwrapProperties();
+        }
+
+        if (initCallback) {
+            initCallback(channel);
+        }
+        channel.exec({type: QWebChannelMessageTypes.idle});
+    });
+};
+
+function QObject(name, data, webChannel)
+{
+    this.__id__ = name;
+    webChannel.objects[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;
+
+    // ----------------------------------------------------------------------
+
+    this.unwrapQObject = function(response)
+    {
+        for (const converter of webChannel.usedConverters) {
+            var result = converter(response);
+            if (result !== undefined)
+                return result;
+        }
+
+        if (response instanceof Array) {
+            // support list of objects
+            return response.map(qobj => object.unwrapQObject(qobj))
+        }
+        if (!(response instanceof Object))
+            return response;
+
+        if (!response["__QObject*__"] || response.id === undefined) {
+            var jObj = {};
+            for (const propName of Object.keys(response)) {
+                jObj[propName] = object.unwrapQObject(response[propName]);
+            }
+            return jObj;
+        }
+
+        var objectId = response.id;
+        if (webChannel.objects[objectId])
+            return webChannel.objects[objectId];
+
+        if (!response.data) {
+            console.error("Cannot unwrap unknown QObject " + objectId + " without data.");
+            return;
+        }
+
+        var qObject = new QObject( objectId, response.data, webChannel );
+        qObject.destroyed.connect(function() {
+            if (webChannel.objects[objectId] === qObject) {
+                delete webChannel.objects[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
+                // NOTE: this detour is necessary to workaround QTBUG-40021
+                Object.keys(qObject).forEach(name => delete qObject[name]);
+            }
+        });
+        // here we are already initialized, and thus must directly unwrap the properties
+        qObject.unwrapProperties();
+        return qObject;
+    }
+
+    this.unwrapProperties = function()
+    {
+        for (const propertyIdx of Object.keys(object.__propertyCache__)) {
+            object.__propertyCache__[propertyIdx] = object.unwrapQObject(object.__propertyCache__[propertyIdx]);
+        }
+    }
+
+    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);
+
+                // only required for "pure" signals, handled separately for properties in propertyUpdate
+                if (isPropertyNotifySignal)
+                    return;
+
+                // also note that we always get notified about the destroyed signal
+                if (signalName === "destroyed" || signalName === "destroyed()" || signalName === "destroyed(QObject*)")
+                    return;
+
+                // and otherwise we only need to be connected only once
+                if (object.__objectSignals__[signalIndex].length == 1) {
+                    webChannel.exec({
+                        type: QWebChannelMessageTypes.connectToSignal,
+                        object: object.__id__,
+                        signal: signalIndex
+                    });
+                }
+            },
+            disconnect: function(callback) {
+                if (typeof(callback) !== "function") {
+                    console.error("Bad callback given to disconnect from signal " + signalName);
+                    return;
+                }
+                // This makes a new list. This is important because it won't interfere with
+                // signal processing if a disconnection happens while emittig a signal
+                object.__objectSignals__[signalIndex] = (object.__objectSignals__[signalIndex] || []).filter(function(c) {
+                  return c != callback;
+                });
+                if (!isPropertyNotifySignal && object.__objectSignals__[signalIndex].length === 0) {
+                    // only required for "pure" signals, handled separately for properties in propertyUpdate
+                    webChannel.exec({
+                        type: QWebChannelMessageTypes.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 (const propertyIndex of Object.keys(propertyMap)) {
+            var propertyValue = propertyMap[propertyIndex];
+            object.__propertyCache__[propertyIndex] = this.unwrapQObject(propertyValue);
+        }
+
+        for (const signalName of Object.keys(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, this.unwrapQObject(signalArgs));
+    }
+
+    function addMethod(methodData)
+    {
+        var methodName = methodData[0];
+        var methodIdx = methodData[1];
+
+        // Fully specified methods are invoked by id, others by name for host-side overload resolution
+        var invokedMethod = methodName[methodName.length - 1] === ')' ? methodIdx : methodName
+
+        object[methodName] = function() {
+            var args = [];
+            var callback;
+            var errCallback;
+            for (var i = 0; i < arguments.length; ++i) {
+                var argument = arguments[i];
+                if (typeof argument === "function")
+                    callback = argument;
+                else
+                    args.push(argument);
+            }
+
+            var result;
+            // during test, webChannel.exec synchronously calls the callback
+            // therefore, the promise must be constucted before calling
+            // webChannel.exec to ensure the callback is set up
+            if (!callback && (typeof(Promise) === 'function')) {
+              result = new Promise(function(resolve, reject) {
+                callback = resolve;
+                errCallback = reject;
+              });
+            }
+
+            webChannel.exec({
+                "type": QWebChannelMessageTypes.invokeMethod,
+                "object": object.__id__,
+                "method": invokedMethod,
+                "args": args
+            }, function(response) {
+                if (response !== undefined) {
+                    var result = object.unwrapQObject(response);
+                    if (callback) {
+                        (callback)(result);
+                    }
+                } else if (errCallback) {
+                  (errCallback)();
+                }
+            });
+
+            return result;
+        };
+    }
+
+    function bindGetterSetter(propertyInfo)
+    {
+        var propertyIndex = propertyInfo[0];
+        var propertyName = propertyInfo[1];
+        var notifySignalData = propertyInfo[2];
+        // initialize property cache with current value
+        // NOTE: if this is an object, it is not directly unwrapped as it might
+        // reference other QObject that we do not know yet
+        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.defineProperty(object, propertyName, {
+            configurable: true,
+            get: function () {
+                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__);
+                }
+
+                return propertyValue;
+            },
+            set: function(value) {
+                if (value === undefined) {
+                    console.warn("Property setter for " + propertyName + " called with undefined value!");
+                    return;
+                }
+                object.__propertyCache__[propertyIndex] = value;
+                var valueToSend = value;
+                webChannel.exec({
+                    "type": QWebChannelMessageTypes.setProperty,
+                    "object": object.__id__,
+                    "property": propertyIndex,
+                    "value": valueToSend
+                });
+            }
+        });
+
+    }
+
+    // ----------------------------------------------------------------------
+
+    data.methods.forEach(addMethod);
+
+    data.properties.forEach(bindGetterSetter);
+
+    data.signals.forEach(function(signal) { addSignal(signal, false); });
+
+    Object.assign(object, data.enums);
+}
+
+QObject.prototype.toJSON = function() {
+    if (this.__id__ === undefined) return {};
+    return {
+        id: this.__id__,
+        "__QObject*__": true
+    };
+};
+
+//required for use with nodejs
+if (typeof module === 'object') {
+    module.exports = {
+        QWebChannel: QWebChannel
+    };
+}