update

example/AppInfo.h

@@ -13,6 +13,7 @@ class AppInfo : public QObject
 public:
     explicit AppInfo(QObject *parent = nullptr);
     Q_INVOKABLE void changeLang(const QString& locale);
+    Q_SIGNAL void activeWindow();
 };
 
 #endif // APPINFO_H

example/CMakeLists.txt

@@ -30,6 +30,7 @@ set(SOURCES
     lang/Lang.cpp
     lang/Zh.cpp
     lang/En.cpp
+    IPC.cpp
 )
 
 set(HEADERS
@@ -39,6 +40,7 @@ set(HEADERS
     lang/Lang.h
     lang/Zh.h
     lang/En.h
+    IPC.h
 )
 
 set(RESOURCES

example/IPC.cpp

@@ -0,0 +1,255 @@
+#include "IPC.h"
+
+#include <QCoreApplication>
+#include <QDebug>
+#include <QThread>
+#include <ctime>
+#include <random>
+
+#ifdef WIN32
+#include <windows.h>
+#else
+#include <unistd.h>
+#endif
+
+IPC::IPC(uint32_t profileId)
+    : profileId{profileId}
+    , globalMemory{"ipc-" IPC_PROTOCOL_VERSION}
+{
+    qRegisterMetaType<IPCEventHandler>("IPCEventHandler");
+    timer.setInterval(EVENT_TIMER_MS);
+    timer.setSingleShot(true);
+    connect(&timer, &QTimer::timeout, this, &IPC::processEvents);
+    std::default_random_engine randEngine((std::random_device())());
+    std::uniform_int_distribution<uint64_t> distribution;
+    globalId = distribution(randEngine);
+    qDebug() << "Our global IPC ID is " << globalId;
+    if (globalMemory.create(sizeof(IPCMemory))) {
+        if (globalMemory.lock()) {
+            IPCMemory* mem = global();
+            memset(mem, 0, sizeof(IPCMemory));
+            mem->globalId = globalId;
+            mem->lastProcessed = time(nullptr);
+            globalMemory.unlock();
+        } else {
+            qWarning() << "Couldn't lock to take ownership";
+        }
+    } else if (globalMemory.attach()) {
+        qDebug() << "Attaching to the global shared memory";
+    } else {
+        qDebug() << "Failed to attach to the global shared memory, giving up. Error:"
+                 << globalMemory.error();
+        return;
+    }
+
+    processEvents();
+}
+
+IPC::~IPC()
+{
+    if (!globalMemory.lock()) {
+        qWarning() << "Failed to lock in ~IPC";
+        return;
+    }
+
+    if (isCurrentOwnerNoLock()) {
+        global()->globalId = 0;
+    }
+    globalMemory.unlock();
+}
+
+time_t IPC::postEvent(const QString& name, const QByteArray& data, uint32_t dest)
+{
+    QByteArray binName = name.toUtf8();
+    if (binName.length() > (int32_t)sizeof(IPCEvent::name)) {
+        return 0;
+    }
+
+    if (data.length() > (int32_t)sizeof(IPCEvent::data)) {
+        return 0;
+    }
+
+    if (!globalMemory.lock()) {
+        qDebug() << "Failed to lock in postEvent()";
+        return 0;
+    }
+
+    IPCEvent* evt = nullptr;
+    IPCMemory* mem = global();
+    time_t result = 0;
+
+    for (uint32_t i = 0; !evt && i < EVENT_QUEUE_SIZE; ++i) {
+        if (mem->events[i].posted == 0) {
+            evt = &mem->events[i];
+        }
+    }
+
+    if (evt) {
+        memset(evt, 0, sizeof(IPCEvent));
+        memcpy(evt->name, binName.constData(), binName.length());
+        memcpy(evt->data, data.constData(), data.length());
+        mem->lastEvent = evt->posted = result = qMax(mem->lastEvent + 1, time(nullptr));
+        evt->dest = dest;
+        evt->sender = GetCurrentProcessId();
+        qDebug() << "postEvent " << name << "to" << dest;
+    }
+    globalMemory.unlock();
+    return result;
+}
+
+bool IPC::isCurrentOwner()
+{
+    if (globalMemory.lock()) {
+        const bool isOwner = isCurrentOwnerNoLock();
+        globalMemory.unlock();
+        return isOwner;
+    } else {
+        qWarning() << "isCurrentOwner failed to lock, returning false";
+        return false;
+    }
+}
+
+void IPC::registerEventHandler(const QString& name, IPCEventHandler handler)
+{
+    eventHandlers[name] = handler;
+}
+
+bool IPC::isEventAccepted(time_t time)
+{
+    bool result = false;
+    if (!globalMemory.lock()) {
+        return result;
+    }
+
+    if (difftime(global()->lastProcessed, time) > 0) {
+        IPCMemory* mem = global();
+        for (uint32_t i = 0; i < EVENT_QUEUE_SIZE; ++i) {
+            if (mem->events[i].posted == time && mem->events[i].processed) {
+                result = mem->events[i].accepted;
+                break;
+            }
+        }
+    }
+    globalMemory.unlock();
+
+    return result;
+}
+
+bool IPC::waitUntilAccepted(time_t postTime, int32_t timeout /*=-1*/)
+{
+    bool result = false;
+    time_t start = time(nullptr);
+    forever
+    {
+        result = isEventAccepted(postTime);
+        if (result || (timeout > 0 && difftime(time(nullptr), start) >= timeout)) {
+            break;
+        }
+
+        qApp->processEvents();
+        QThread::msleep(0);
+    }
+    return result;
+}
+
+bool IPC::isAttached() const
+{
+    return globalMemory.isAttached();
+}
+
+void IPC::setProfileId(uint32_t profileId)
+{
+    this->profileId = profileId;
+}
+
+IPC::IPCEvent* IPC::fetchEvent()
+{
+    IPCMemory* mem = global();
+    for (uint32_t i = 0; i < EVENT_QUEUE_SIZE; ++i) {
+        IPCEvent* evt = &mem->events[i];
+        if ((evt->processed && difftime(time(nullptr), evt->processed) > EVENT_GC_TIMEOUT)
+            || (!evt->processed && difftime(time(nullptr), evt->posted) > EVENT_GC_TIMEOUT)) {
+            memset(evt, 0, sizeof(IPCEvent));
+        }
+
+        if (evt->posted && !evt->processed && evt->sender != GetCurrentProcessId()
+            && (evt->dest == profileId || (evt->dest == 0 && isCurrentOwnerNoLock()))) {
+            return evt;
+        }
+    }
+
+    return nullptr;
+}
+
+bool IPC::runEventHandler(IPCEventHandler handler, const QByteArray& arg)
+{
+    bool result = false;
+    if (QThread::currentThread() == qApp->thread()) {
+        result = handler(arg);
+    } else {
+        QMetaObject::invokeMethod(this, "runEventHandler", Qt::BlockingQueuedConnection,
+                                  Q_RETURN_ARG(bool, result), Q_ARG(IPCEventHandler, handler),
+                                  Q_ARG(const QByteArray&, arg));
+    }
+    return result;
+}
+
+void IPC::processEvents()
+{
+    if (!globalMemory.lock()) {
+        timer.start();
+        return;
+    }
+
+    IPCMemory* mem = global();
+
+    if (mem->globalId == globalId) {
+        mem->lastProcessed = time(nullptr);
+    } else {
+        if (difftime(time(nullptr), mem->lastProcessed) >= OWNERSHIP_TIMEOUT_S) {
+            qDebug() << "Previous owner timed out, taking ownership" << mem->globalId << "->"
+                     << globalId;
+            memset(mem, 0, sizeof(IPCMemory));
+            mem->globalId = globalId;
+            mem->lastProcessed = time(nullptr);
+        }
+    }
+
+    while (IPCEvent* evt = fetchEvent()) {
+        QString name = QString::fromUtf8(evt->name);
+        auto it = eventHandlers.find(name);
+        if (it != eventHandlers.end()) {
+            evt->accepted = runEventHandler(it.value(), evt->data);
+            qDebug() << "Processed event:" << name << "posted:" << evt->posted
+                     << "accepted:" << evt->accepted;
+            if (evt->dest == 0) {
+                if (evt->accepted) {
+                    evt->processed = time(nullptr);
+                }
+            } else {
+                evt->processed = time(nullptr);
+            }
+        } else {
+            qDebug() << "Received event:" << name << "without handler";
+            qDebug() << "Available handlers:" << eventHandlers.keys();
+        }
+    }
+
+    globalMemory.unlock();
+    timer.start();
+}
+
+bool IPC::isCurrentOwnerNoLock()
+{
+    const void* const data = globalMemory.data();
+    if (!data) {
+        qWarning() << "isCurrentOwnerNoLock failed to access the memory, returning false";
+        return false;
+    }
+    return (*static_cast<const uint64_t*>(data) == globalId);
+}
+
+IPC::IPCMemory* IPC::global()
+{
+    return static_cast<IPCMemory*>(globalMemory.data());
+}

example/IPC.h

@@ -0,0 +1,75 @@
+#ifndef IPC_H
+#define IPC_H
+
+#include <QMap>
+#include <QObject>
+#include <QSharedMemory>
+#include <QTimer>
+#include <ctime>
+#include <functional>
+
+using IPCEventHandler = std::function<bool(const QByteArray&)>;
+
+#define IPC_PROTOCOL_VERSION "1"
+
+class IPC : public QObject
+{
+    Q_OBJECT
+
+protected:
+    static const int EVENT_TIMER_MS = 1000;
+    static const int EVENT_GC_TIMEOUT = 5;
+    static const int EVENT_QUEUE_SIZE = 32;
+    static const int OWNERSHIP_TIMEOUT_S = 5;
+
+public:
+    IPC(uint32_t profileId);
+    ~IPC();
+
+    struct IPCEvent
+    {
+        uint32_t dest;
+        int32_t sender;
+        char name[16];
+        char data[128];
+        time_t posted;
+        time_t processed;
+        uint32_t flags;
+        bool accepted;
+        bool global;
+    };
+
+    struct IPCMemory
+    {
+        uint64_t globalId;
+        time_t lastEvent;
+        time_t lastProcessed;
+        IPCEvent events[IPC::EVENT_QUEUE_SIZE];
+    };
+
+    time_t postEvent(const QString& name, const QByteArray& data = QByteArray(), uint32_t dest = 0);
+    bool isCurrentOwner();
+    void registerEventHandler(const QString& name, IPCEventHandler handler);
+    bool isEventAccepted(time_t time);
+    bool waitUntilAccepted(time_t time, int32_t timeout = -1);
+    bool isAttached() const;
+
+public slots:
+    void setProfileId(uint32_t profileId);
+
+private:
+    IPCMemory* global();
+    bool runEventHandler(IPCEventHandler handler, const QByteArray& arg);
+    IPCEvent* fetchEvent();
+    void processEvents();
+    bool isCurrentOwnerNoLock();
+
+private:
+    QTimer timer;
+    uint64_t globalId;
+    uint32_t profileId;
+    QSharedMemory globalMemory;
+    QMap<QString, IPCEventHandler> eventHandlers;
+};
+
+#endif // IPC_H

example/example.pro

@@ -8,7 +8,8 @@ HEADERS += \
     lang/Zh.h \
     stdafx.h \
     ChatController.h \
-    AppInfo.h
+    AppInfo.h \
+    IPC.h
 
 SOURCES += \
         ChatController.cpp \
@@ -16,7 +17,8 @@ SOURCES += \
         lang/En.cpp \
         lang/Lang.cpp \
         lang/Zh.cpp \
-        main.cpp
+        main.cpp \
+        IPC.cpp
 
 RESOURCES += qml.qrc
 

example/main.cpp

@@ -7,6 +7,7 @@
 #include "lang/Lang.h"
 #include "AppInfo.h"
 #include "ChatController.h"
+#include "IPC.h"
 
 int main(int argc, char *argv[])
 {
@@ -21,10 +22,23 @@ int main(int argc, char *argv[])
     QGuiApplication::setApplicationName("FluentUI");
     //    QQuickWindow::setGraphicsApi(QSGRendererInterface::Software);
     QGuiApplication app(argc, argv);
+    AppInfo* appInfo = new AppInfo();
+    IPC ipc(0);
+    QString activeWindowEvent = "activeWindow";
+    if(!ipc.isCurrentOwner()){
+        ipc.postEvent(activeWindowEvent,QString().toUtf8(),0);
+        delete appInfo;
+        return 0;
+    }
+    if(ipc.isAttached()){
+        ipc.registerEventHandler(activeWindowEvent,[&appInfo](const QByteArray& data){
+            Q_EMIT appInfo->activeWindow();
+            return true;
+        });
+    }
     app.setQuitOnLastWindowClosed(false);
     QQmlApplicationEngine engine;
     qmlRegisterType<ChatController>("Controller",1,0,"ChatController");
-    AppInfo* appInfo = new AppInfo();
     QQmlContext * context = engine.rootContext();
     Lang* lang = appInfo->lang();
     context->setContextProperty("lang",lang);

example/page/MainPage.qml

@@ -20,6 +20,15 @@ FluWindow {
         event.accepted = false
     }
 
+    Connections{
+        target: appInfo
+        function onActiveWindow(){
+            window.show()
+            window.raise()
+            window.requestActivate()
+        }
+    }
+
     FluAppBar{
         id:appbar
         z:9