refactor: The Clipboard operations in the Wayland

1. 整理所有信号的连接与创建，避免重复连接和内存泄漏的情况。
2. 通过创建一个统一的线程管理机制[服务流机制]，管理所有获取
的拷贝和粘贴操作指令。
    其中，用两种不同的服务流来分别管理拷贝和粘贴，拷贝流在
每一次用户操作 Ctrl + c 时都会重新创建，流程执行完毕后自动
退出回收;粘贴流由于执行指令类似，因此将其放在同一个流中进行
后台监听，当用户使用 Ctrl + v 时，不断的向流中放置消息，使
流开始正常工作。
    服务流使用责任链模式实现，每一个服务存在不同的指令，每个
指令在子线程中执行不同的任务，并将结果发送给下一个服务中的指
令，直到服务结束。多个服务串行，形成最终的服务流。
3. 由于窗管对信号中指针的接受，没有进行线程安全的操作，因此
最终实现时增加了较多的线程同步机制，以防止出现野指针

Log:
Influence: Wayland clipboard

CMakeLists.txt

@@ -139,6 +139,8 @@ install(TARGETS ${BIN_NAME} DESTINATION bin)
 set(BIN_NAME dde-clipboard-daemon)
 
 file(GLOB_RECURSE dde-clipboard-daemon_SCRS
+   "dde-clipboard-daemon/serviceflow/*.h"
+   "dde-clipboard-daemon/serviceflow/*.cpp"
    "dde-clipboard-daemon/*.h"
    "dde-clipboard-daemon/*.cpp"
 )

dde-clipboard-daemon/clipboardloader.cpp

@@ -90,7 +90,6 @@ ClipboardLoader::ClipboardLoader(QObject *parent)
     if (qEnvironmentVariable("XDG_SESSION_TYPE").contains("wayland")) {
 #ifdef USE_DEEPIN_KF5_WAYLAND
         m_waylandCopyClient = new WaylandCopyClient(this);
-        m_waylandCopyClient->init();
 
         connect(m_waylandCopyClient, &WaylandCopyClient::dataChanged, this, [this] {
             this->doWork(WAYLAND_PROTOCOL);

dde-clipboard-daemon/serviceflow/command.cpp

@@ -0,0 +1,73 @@
+#include "command.h"
+#include "servicetool.h"
+#include <QThread>
+
+Command::Command(CommandService *service)
+    : m_service(service)
+{
+    setAutoDelete(true);
+}
+
+void Command::exit()
+{
+    m_isExit = true;
+}
+
+Command::State Command::state() const
+{
+    return m_state;
+}
+
+CommandService *Command::service() const
+{
+    return m_service;
+}
+
+void Command::installMessageExtractor(Extractor *extractor)
+{
+    Q_ASSERT(extractor);
+    switch (extractor->direction()) {
+    case Extractor::CommandToTransporter: {
+        if (m_outEx) {
+            qWarning("This command already has the out direction Extractor.");
+            return;
+        }
+        m_outEx = extractor;
+    }
+        break;
+    case Extractor::TransporterToCommand: {
+        if (m_inEx) {
+            qWarning("This command already has the in direction Extractor.");
+            return;
+        }
+        m_inEx = extractor;
+    }
+        break;
+    }
+}
+
+void Command::run()
+{
+    Q_ASSERT(m_inEx);
+    while (true) {
+        m_state = Preparing;
+        CommandMessage *msg = m_inEx->takeFromTransporter();
+        if (m_isExit) {
+            delete msg;
+            break;
+        }
+
+        m_state = Running;
+        QList<CommandMessage *> destMsgs = doExecute(msg);
+
+        // 允许复用同一个 msg 的情况
+        if (!destMsgs.contains(msg))
+            delete msg;
+
+        if (m_outEx) {
+            for (auto destMsg : destMsgs)
+                m_outEx->pushToTransporter(destMsg);
+        }
+    }
+    m_state = Preparing;
+}

dde-clipboard-daemon/serviceflow/command.h

@@ -0,0 +1,37 @@
+#ifndef COMMAND
+#define COMMAND
+
+#include <QRunnable>
+
+class CommandService;
+class CommandMessage;
+class Extractor;
+class Command : public QRunnable
+{
+public:
+    enum State {
+        Preparing,
+        Running
+    };
+    Command(CommandService *service = nullptr);
+
+    virtual QList<CommandMessage *> doExecute(CommandMessage *) = 0;
+    virtual QString name() const = 0;
+
+    void exit();
+    State state() const;
+
+    CommandService *service() const;
+    void installMessageExtractor(Extractor *extractor);
+
+private:
+    void run() override;
+
+    Extractor * m_inEx = nullptr;
+    Extractor * m_outEx = nullptr;
+    bool m_isExit = false;
+    State m_state = Preparing;
+    CommandService *m_service = nullptr;
+};
+
+#endif  // COMMANDMESSAGE

dde-clipboard-daemon/serviceflow/commandmessage.h

@@ -0,0 +1,27 @@
+#ifndef COMMANDMESSAGE
+#define COMMANDMESSAGE
+
+class CommandMessage
+{
+public:
+    enum Error {
+        NoError,
+        ExecuteError
+    };
+
+    CommandMessage() = default;
+    virtual ~CommandMessage() {}
+
+    inline Error error() const {
+        return m_error;
+    }
+
+    inline void setError(Error err) {
+        m_error = err;
+    }
+
+protected:
+    Error m_error = NoError;
+};
+
+#endif  // COMMANDMESSAGE

dde-clipboard-daemon/serviceflow/commandservice.cpp

@@ -0,0 +1,21 @@
+#include "commandservice.h"
+
+CommandService::CommandService()
+{
+
+}
+
+CommandService::~CommandService()
+{
+
+}
+
+CommandService *CommandService::nextService() const
+{
+    return this->m_nextService;
+}
+
+void CommandService::setNextService(CommandService *service)
+{
+    this->m_nextService = service;
+}

dde-clipboard-daemon/serviceflow/commandservice.h

@@ -0,0 +1,21 @@
+#ifndef COMMANDSERVICE
+#define COMMANDSERVICE
+
+#include "command.h"
+
+class CommandService
+{
+public:
+    CommandService();
+    virtual ~CommandService();
+
+    virtual QList<Command *> commands() = 0;
+
+    CommandService *nextService() const;
+    void setNextService(CommandService* service);
+
+private:
+    CommandService* m_nextService;
+};
+
+#endif  // COMMANDSERVICE