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++ // Copyright (C) 2025 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
++ // Qt-Security score:significant reason:default
++
++ #ifndef QRANDOMACCESSASYNCFILE_P_P_H
++ #define QRANDOMACCESSASYNCFILE_P_P_H
++
++ //
++ // W A R N I N G
++ // -------------
++ //
++ // This file is not part of the Qt API. It exists purely as an
++ // implementation detail. This header file may change from version to
++ // version without notice, or even be removed.
++ //
++ // We mean it.
++ //
++
++ #include "qrandomaccessasyncfile_p.h"
++
++ #include <QtCore/private/qobject_p.h>
++
++ #include <QtCore/qstring.h>
++
++ #if QT_CONFIG(future) && QT_CONFIG(thread)
++
++ #include <QtCore/private/qfsfileengine_p.h>
++
++ #include <QtCore/qfuturewatcher.h>
++ #include <QtCore/qmutex.h>
++ #include <QtCore/qqueue.h>
++
++ #endif // future && thread
++
++ #ifdef Q_OS_DARWIN
++
++ #include <QtCore/qlist.h>
++ #include <QtCore/qmutex.h>
++ #include <QtCore/qset.h>
++ #include <QtCore/qwaitcondition.h>
++
++ #include <dispatch/dispatch.h>
++
++ #endif // Q_OS_DARWIN
++
++ #ifdef QT_RANDOMACCESSASYNCFILE_QIORING
++ #include <QtCore/private/qioring_p.h>
++ #include <QtCore/qlist.h>
++ #endif
++
++ QT_BEGIN_NAMESPACE
++
++ class QRandomAccessAsyncFileBackend
++ {
++ Q_DISABLE_COPY_MOVE(QRandomAccessAsyncFileBackend)
++ public:
++ explicit QRandomAccessAsyncFileBackend(QRandomAccessAsyncFile *owner);
++ virtual ~QRandomAccessAsyncFileBackend();
++
++ virtual bool init() = 0;
++ virtual void cancelAndWait(QIOOperation *op) = 0;
++
++ virtual void close() = 0;
++ virtual qint64 size() const = 0;
++
++ [[nodiscard]] virtual QIOOperation *open(const QString &path, QIODeviceBase::OpenMode mode) = 0;
++ [[nodiscard]] virtual QIOOperation *flush() = 0;
++
++ [[nodiscard]] virtual QIOReadOperation *read(qint64 offset, qint64 maxSize) = 0;
++ [[nodiscard]] virtual QIOWriteOperation *write(qint64 offset, const QByteArray &data) = 0;
++ [[nodiscard]] virtual QIOWriteOperation *write(qint64 offset, QByteArray &&data) = 0;
++
++ [[nodiscard]] virtual QIOVectoredReadOperation *
++ readInto(qint64 offset, QSpan<std::byte> buffer) = 0;
++ [[nodiscard]] virtual QIOVectoredWriteOperation *
++ writeFrom(qint64 offset, QSpan<const std::byte> buffer) = 0;
++
++ [[nodiscard]] virtual QIOVectoredReadOperation *
++ readInto(qint64 offset, QSpan<const QSpan<std::byte>> buffers) = 0;
++ [[nodiscard]] virtual QIOVectoredWriteOperation *
++ writeFrom(qint64 offset, QSpan<const QSpan<const std::byte>> buffers) = 0;
++ protected:
++ // common for all backends
++ enum class FileState : quint8
++ {
++ Closed,
++ OpenPending, // already got an open request
++ Opened,
++ };
++
++ QString m_filePath;
++ QRandomAccessAsyncFile *m_owner = nullptr;
++ QIODeviceBase::OpenMode m_openMode;
++ FileState m_fileState = FileState::Closed;
++ };
++
++ class QRandomAccessAsyncFilePrivate : public QObjectPrivate
++ {
++ Q_DECLARE_PUBLIC(QRandomAccessAsyncFile)
++ Q_DISABLE_COPY_MOVE(QRandomAccessAsyncFilePrivate)
++ public:
++ QRandomAccessAsyncFilePrivate();
++ ~QRandomAccessAsyncFilePrivate() override;
++
++ static QRandomAccessAsyncFilePrivate *get(QRandomAccessAsyncFile *file)
++ { return file->d_func(); }
++
++ void init();
++ void cancelAndWait(QIOOperation *op)
++ {
++ checkValid();
++ m_backend->cancelAndWait(op);
++ }
++
++ void close()
++ {
++ checkValid();
++ m_backend->close();
++ }
++ qint64 size() const
++ {
++ checkValid();
++ return m_backend->size();
++ }
++
++ [[nodiscard]] QIOOperation *open(const QString &path, QIODeviceBase::OpenMode mode)
++ {
++ checkValid();
++ return m_backend->open(path, mode);
++ }
++ [[nodiscard]] QIOOperation *flush()
++ {
++ checkValid();
++ return m_backend->flush();
++ }
++
++ [[nodiscard]] QIOReadOperation *read(qint64 offset, qint64 maxSize)
++ {
++ checkValid();
++ return m_backend->read(offset, maxSize);
++ }
++ [[nodiscard]] QIOWriteOperation *write(qint64 offset, const QByteArray &data)
++ {
++ checkValid();
++ return m_backend->write(offset, data);
++ }
++ [[nodiscard]] QIOWriteOperation *write(qint64 offset, QByteArray &&data)
++ {
++ checkValid();
++ return m_backend->write(offset, std::move(data));
++ }
++
++ [[nodiscard]] QIOVectoredReadOperation *readInto(qint64 offset, QSpan<std::byte> buffer)
++ {
++ checkValid();
++ return m_backend->readInto(offset, buffer);
++ }
++ [[nodiscard]] QIOVectoredWriteOperation *writeFrom(qint64 offset, QSpan<const std::byte> buffer)
++ {
++ checkValid();
++ return m_backend->writeFrom(offset, buffer);
++ }
++
++ [[nodiscard]] QIOVectoredReadOperation *readInto(qint64 offset,
++ QSpan<const QSpan<std::byte>> buffers)
++ {
++ checkValid();
++ return m_backend->readInto(offset, buffers);
++ }
++ [[nodiscard]] QIOVectoredWriteOperation *writeFrom(qint64 offset,
++ QSpan<const QSpan<const std::byte>> buffers)
++ {
++ checkValid();
++ return m_backend->writeFrom(offset, buffers);
++ }
++
++ private:
++ void checkValid() const { Q_ASSERT(m_backend); }
++ std::unique_ptr<QRandomAccessAsyncFileBackend> m_backend;
++
++ };
++
++
++ #if defined(QT_RANDOMACCESSASYNCFILE_QIORING) || defined(Q_OS_DARWIN)
++ class QRandomAccessAsyncFileNativeBackend final : public QRandomAccessAsyncFileBackend
++ {
++ Q_DISABLE_COPY_MOVE(QRandomAccessAsyncFileNativeBackend)
++ public:
++ explicit QRandomAccessAsyncFileNativeBackend(QRandomAccessAsyncFile *owner);
++ ~QRandomAccessAsyncFileNativeBackend();
++
++ bool init() override;
++ void cancelAndWait(QIOOperation *op) override;
++
++ void close() override;
++ qint64 size() const override;
++
++ [[nodiscard]] QIOOperation *open(const QString &path, QIODeviceBase::OpenMode mode) override;
++ [[nodiscard]] QIOOperation *flush() override;
++
++ [[nodiscard]] QIOReadOperation *read(qint64 offset, qint64 maxSize) override;
++ [[nodiscard]] QIOWriteOperation *write(qint64 offset, const QByteArray &data) override;
++ [[nodiscard]] QIOWriteOperation *write(qint64 offset, QByteArray &&data) override;
++
++ [[nodiscard]] QIOVectoredReadOperation *
++ readInto(qint64 offset, QSpan<std::byte> buffer) override;
++ [[nodiscard]] QIOVectoredWriteOperation *
++ writeFrom(qint64 offset, QSpan<const std::byte> buffer) override;
++
++ [[nodiscard]] QIOVectoredReadOperation *
++ readInto(qint64 offset, QSpan<const QSpan<std::byte>> buffers) override;
++ [[nodiscard]] QIOVectoredWriteOperation *
++ writeFrom(qint64 offset, QSpan<const QSpan<const std::byte>> buffers) override;
++
++ private:
++ #if defined(QT_RANDOMACCESSASYNCFILE_QIORING)
++ void queueCompletion(QIOOperationPrivate *priv, QIOOperation::Error error);
++ void startReadIntoSingle(QIOOperation *op, const QSpan<std::byte> &to);
++ void startWriteFromSingle(QIOOperation *op, const QSpan<const std::byte> &from);
++ QIORing::RequestHandle cancel(QIORing::RequestHandle handle);
++ QIORing *m_ioring = nullptr;
++ qintptr m_fd = -1;
++ QList<QPointer<QIOOperation>> m_operations;
++ QHash<QIOOperation *, QIORing::RequestHandle> m_opHandleMap;
++ #endif
++ #ifdef Q_OS_DARWIN
++ using OperationId = quint64;
++ static constexpr OperationId kInvalidOperationId = 0;
++ static constexpr OperationId kAllOperationIds = std::numeric_limits<OperationId>::max();
++
++ struct OperationResult
++ {
++ OperationId opId;
++ qint64 result; // num bytes processed or file descriptor
++ int error;
++ };
++
++ enum class OpState : quint8
++ {
++ Pending,
++ Running,
++ };
++
++ struct OperationInfo
++ {
++ OperationId opId;
++ dispatch_io_t channel;
++ QPointer<QIOOperation> operation;
++ OpState state;
++
++ OperationInfo(OperationId _id, QIOOperation *_op)
++ : opId(_id),
++ channel(nullptr),
++ operation(_op),
++ state(OpState::Pending)
++ {}
++ };
++
++ // We need to maintain an actual queue of the operations, because
++ // certain operations (i.e. flush) should act like barriers. The docs
++ // for dispatch_io_barrier mention that it can synchronize between multiple
++ // channels handling the same file descriptor, but that DOES NOT work in
++ // practice. It works correctly only when there's a signle IO channel. But
++ // with a signle IO channel we're not able to cancel individual operations.
++ // As a result, we need to make sure that all previous operations are
++ // completed before starting a barrier operation. Similarly, we cannot start
++ // any other operation until a barrier operation is finished.
++ QList<OperationInfo> m_operations;
++ dispatch_io_t m_ioChannel = nullptr;
++ int m_fd = -1;
++
++ QMutex m_mutex;
++ // the members below should only be accessed with the mutex
++ OperationId m_opToCancel = kInvalidOperationId;
++ QSet<OperationId> m_runningOps;
++ qsizetype m_numChannelsToClose = 0;
++ QWaitCondition m_cancellationCondition;
++
++ static OperationId getNextId();
++
++ template <typename Operation, typename ...Args>
++ Operation *addOperation(QIOOperation::Type type, qint64 offset, Args &&...args);
++
++ void notifyIfOperationsAreCompleted();
++ dispatch_io_t createMainChannel(int fd);
++ dispatch_io_t duplicateIoChannel(OperationId opId);
++ void closeIoChannel(dispatch_io_t channel);
++ void releaseIoChannel(dispatch_io_t channel);
++ void handleOperationComplete(const OperationResult &opResult);
++
++ void queueCompletion(OperationId opId, int error);
++
++ void startOperationsUntilBarrier();
++ void executeRead(OperationInfo &opInfo);
++ void executeWrite(OperationInfo &opInfo);
++ void executeFlush(OperationInfo &opInfo);
++ void executeOpen(OperationInfo &opInfo);
++
++ void readOneBuffer(OperationId opId, qsizetype bufferIdx, qint64 alreadyRead);
++ void readOneBufferHelper(OperationId opId, dispatch_io_t channel, qint64 offset,
++ void *bytesPtr, qint64 maxSize, qsizetype currentBufferIdx,
++ qsizetype totalBuffers, qint64 alreadyRead);
++ void writeHelper(OperationId opId, dispatch_io_t channel, qint64 offset,
++ dispatch_data_t dataToWrite, qint64 dataSize);
++ #endif
++ };
++ #endif // QIORing || macOS
++
++ #if QT_CONFIG(future) && QT_CONFIG(thread)
++ class QRandomAccessAsyncFileThreadPoolBackend : public QRandomAccessAsyncFileBackend
++ {
++ Q_DISABLE_COPY_MOVE(QRandomAccessAsyncFileThreadPoolBackend)
++ public:
++ explicit QRandomAccessAsyncFileThreadPoolBackend(QRandomAccessAsyncFile *owner);
++ ~QRandomAccessAsyncFileThreadPoolBackend();
++
++ bool init() override;
++ void cancelAndWait(QIOOperation *op) override;
++
++ void close() override;
++ qint64 size() const override;
++
++ [[nodiscard]] QIOOperation *open(const QString &path, QIODeviceBase::OpenMode mode) override;
++ [[nodiscard]] QIOOperation *flush() override;
++
++ [[nodiscard]] QIOReadOperation *read(qint64 offset, qint64 maxSize) override;
++ [[nodiscard]] QIOWriteOperation *write(qint64 offset, const QByteArray &data) override;
++ [[nodiscard]] QIOWriteOperation *write(qint64 offset, QByteArray &&data) override;
++
++ [[nodiscard]] QIOVectoredReadOperation *
++ readInto(qint64 offset, QSpan<std::byte> buffer) override;
++ [[nodiscard]] QIOVectoredWriteOperation *
++ writeFrom(qint64 offset, QSpan<const std::byte> buffer) override;
++
++ [[nodiscard]] QIOVectoredReadOperation *
++ readInto(qint64 offset, QSpan<const QSpan<std::byte>> buffers) override;
++ [[nodiscard]] QIOVectoredWriteOperation *
++ writeFrom(qint64 offset, QSpan<const QSpan<const std::byte>> buffers) override;
++
++ struct OperationResult
++ {
++ qint64 bytesProcessed; // either read or written
++ QIOOperation::Error error;
++ };
++ private:
++
++ mutable QBasicMutex m_engineMutex;
++ std::unique_ptr<QFSFileEngine> m_engine;
++ QFutureWatcher<OperationResult> m_watcher;
++
++ QQueue<QPointer<QIOOperation>> m_operations;
++ QPointer<QIOOperation> m_currentOperation;
++ qsizetype numProcessedBuffers = 0;
++
++ void executeNextOperation();
++ void processBufferAt(qsizetype idx);
++ void processFlush();
++ void processOpen();
++ void operationComplete();
++ };
++ #endif // future && thread
++
++ QT_END_NAMESPACE
++
++ #endif // QRANDOMACCESSASYNCFILE_P_P_H