qt-creator/src/libs/utils/launchersocket.h

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** Copyright (C) 2021 The Qt Company Ltd.
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#pragma once

#include "environment.h"
#include "filepath.h"
#include "launcherpackets.h"
#include "processinterface.h"

#include <QDeadlineTimer>
#include <QHash>
#include <QMutex>
#include <QObject>
#include <QProcess>
#include <QWaitCondition>

#include <atomic>
#include <memory>
#include <vector>

QT_BEGIN_NAMESPACE
class QLocalSocket;
QT_END_NAMESPACE

namespace Utils {
namespace Internal {

class LauncherInterfacePrivate;
class LauncherHandle;
class LauncherSignal;
class ErrorSignal;
class StartedSignal;
class ReadyReadSignal;
class FinishedSignal;

// All the methods and data fields in this class are called / accessed from the caller's thread.
// Exceptions are explicitly marked.
class CallerHandle : public QObject
{
    Q_OBJECT
public:
    enum class SignalType {
        NoSignal,
        Error,
        Started,
        ReadyRead,
        Finished
    };
    Q_ENUM(SignalType)
    CallerHandle(QObject *parent, quintptr token)
        : QObject(parent), m_token(token) {}
    ~CallerHandle() override;

    LauncherHandle *launcherHandle() const { return m_launcherHandle; }
    void setLauncherHandle(LauncherHandle *handle) { QMutexLocker locker(&m_mutex); m_launcherHandle = handle; }

    bool waitForStarted(int msecs);
    bool waitForReadyRead(int msces);
    bool waitForFinished(int msecs);

    // Returns the list of flushed signals.
    QList<SignalType> flush();
    QList<SignalType> flushFor(SignalType signalType);
    bool shouldFlushFor(SignalType signalType) const;
    // Called from launcher's thread exclusively.
    void appendSignal(LauncherSignal *launcherSignal);

    // Called from caller's or launcher's thread.
    QProcess::ProcessState state() const;
    void cancel();

    QByteArray readAllStandardOutput();
    QByteArray readAllStandardError();

    qint64 processId() const;
    int exitCode() const;
    QString errorString() const;
    void setErrorString(const QString &str);

    void start(const QString &program, const QStringList &arguments);
    // Called from caller's or launcher's thread.
    void startIfNeeded();

    qint64 write(const QByteArray &data);

    QProcess::ProcessError error() const;
    // Called from caller's or launcher's thread.
    QString program() const;
    // Called from caller's or launcher's thread.
    QStringList arguments() const;
    void setProcessSetupData(const ProcessSetupData &setup);
    QProcess::ExitStatus exitStatus() const;

signals:
    void errorOccurred(QProcess::ProcessError error);
    void started();
    void finished();
    void readyReadStandardOutput();
    void readyReadStandardError();

private:
    bool waitForSignal(int msecs, CallerHandle::SignalType newSignal);
    bool canWaitFor(SignalType newSignal) const; // TODO: employ me before calling waitForSignal()

    // Called from caller's or launcher's thread. Call me with mutex locked.
    void doStart();
    // Called from caller's or launcher's thread.
    void sendPacket(const Internal::LauncherPacket &packet);
    // Called from caller's or launcher's thread.
    bool isCalledFromCallersThread() const;
    // Called from caller's or launcher's thread. Call me with mutex locked.
    bool isCalledFromLaunchersThread() const;

    QByteArray readAndClear(QByteArray &data) const
    {
        const QByteArray tmp = data;
        data.clear();
        return tmp;
    }

    void handleError(const ErrorSignal *launcherSignal);
    void handleStarted(const StartedSignal *launcherSignal);
    void handleReadyRead(const ReadyReadSignal *launcherSignal);
    void handleFinished(const FinishedSignal *launcherSignal);

    // Lives in launcher's thread. Modified from caller's thread.
    LauncherHandle *m_launcherHandle = nullptr;

    mutable QMutex m_mutex;
    // Accessed from caller's and launcher's thread
    QList<LauncherSignal *> m_signals;

    const quintptr m_token;

    // Modified from caller's thread, read from launcher's thread
    std::atomic<QProcess::ProcessState> m_processState = QProcess::NotRunning;
    std::unique_ptr<StartProcessPacket> m_startPacket;
    int m_processId = 0;
    int m_exitCode = 0;
    QProcess::ExitStatus m_exitStatus = QProcess::ExitStatus::NormalExit;
    QByteArray m_stdout;
    QByteArray m_stderr;
    QProcess::ProcessError m_error = QProcess::UnknownError;

    QString m_command;
    QStringList m_arguments;
    ProcessSetupData m_setup;
};

// Moved to the launcher thread, returned to caller's thread.
// It's assumed that this object will be alive at least
// as long as the corresponding QtcProcess is alive.

class LauncherHandle : public QObject
{
    Q_OBJECT
public:
    // Called from caller's thread, moved to launcher's thread afterwards.
    LauncherHandle(quintptr token) : m_token(token) {}
    // Called from caller's thread exclusively.
    bool waitForSignal(int msecs, CallerHandle::SignalType newSignal);
    CallerHandle *callerHandle() const { return m_callerHandle; }
    void setCallerHandle(CallerHandle *handle) { QMutexLocker locker(&m_mutex); m_callerHandle = handle; }
    // Called from caller's thread exclusively.
    void setCanceled() { m_awaitingShouldContinue = false; }

    // Called from launcher's thread exclusively.
    void handleSocketReady();
    void handleSocketError(const QString &message);
    void handlePacket(LauncherPacketType type, const QByteArray &payload);

    // Called from caller's thread exclusively.
    bool isSocketError() const { return m_socketError; }

private:
    // Called from caller's thread exclusively.
    bool doWaitForSignal(QDeadlineTimer deadline, CallerHandle::SignalType newSignal);
    // Called from launcher's thread exclusively. Call me with mutex locked.
    void wakeUpIfWaitingFor(CallerHandle::SignalType newSignal);

    // Called from launcher's thread exclusively. Call me with mutex locked.
    void flushCaller();
    // Called from launcher's thread exclusively.
    void handleErrorPacket(const QByteArray &packetData);
    void handleStartedPacket(const QByteArray &packetData);
    void handleReadyReadStandardOutput(const QByteArray &packetData);
    void handleReadyReadStandardError(const QByteArray &packetData);
    void handleFinishedPacket(const QByteArray &packetData);

    // Called from caller's or launcher's thread.
    bool isCalledFromLaunchersThread() const;
    bool isCalledFromCallersThread() const;

    // Lives in caller's thread. Modified only in caller's thread. TODO: check usages - all should be with mutex
    CallerHandle *m_callerHandle = nullptr;

    // Modified only in caller's thread.
    bool m_awaitingShouldContinue = false;
    mutable QMutex m_mutex;
    QWaitCondition m_waitCondition;
    const quintptr m_token;
    std::atomic_bool m_socketError = false;
    // Modified only in caller's thread.
    CallerHandle::SignalType m_waitingFor = CallerHandle::SignalType::NoSignal;
};

class LauncherSocket : public QObject
{
    Q_OBJECT
    friend class LauncherInterfacePrivate;
public:
    // Called from caller's or launcher's thread.
    bool isReady() const { return m_socket.load(); }
    void sendData(const QByteArray &data);

    // Called from caller's thread exclusively.
    CallerHandle *registerHandle(QObject *parent, quintptr token);
    void unregisterHandle(quintptr token);

signals:
    void ready();
    void errorOccurred(const QString &error);

private:
    // Called from caller's thread, moved to launcher's thread.
    LauncherSocket(QObject *parent = nullptr);
    // Called from launcher's thread exclusively.
    ~LauncherSocket() override;

    // Called from launcher's thread exclusively.
    LauncherHandle *handleForToken(quintptr token) const;

    // Called from launcher's thread exclusively.
    void setSocket(QLocalSocket *socket);
    void shutdown();

    // Called from launcher's thread exclusively.
    void handleSocketError();
    void handleSocketDataAvailable();
    void handleSocketDisconnected();
    void handleError(const QString &error);
    void handleRequests();

    // Called from caller's or launcher's thread.
    bool isCalledFromLaunchersThread() const;

    std::atomic<QLocalSocket *> m_socket{nullptr};
    PacketParser m_packetParser;
    std::vector<QByteArray> m_requests;
    mutable QMutex m_mutex;
    QHash<quintptr, LauncherHandle *> m_handles;
};

} // namespace Internal
} // namespace Utils