quickmod/FuseMounter/fuseinterface.h

#ifndef FUSEINTERFACE_H
#define FUSEINTERFACE_H

#include <QCache>
#include <QDateTime>
#include <QDir>
#include <QFileSystemWatcher>
#include <QMutex>
#include <QObject>
#include <QSharedPointer>
#include <QSocketNotifier>
#include <QSqlDatabase>

extern "C" {
#define FUSE_USE_VERSION 31

#include <fuse3/fuse.h>
#include <fuse3/fuse_lowlevel.h>
#include <fcntl.h>
#include <stdarg.h>
#include <unarr.h>
#include <unistd.h>
}

//#include "database.h"

struct VFSStatEntry {
    QString     path;
    time_t      lastAccess;
    quint32     openCount;
    quint32     refCount;
    qint8       type;
};

class FuseAccessorBase;
class FuseFHBase;
class FuseInterface : public QObject
{
    Q_OBJECT

    int                 m_fuse_id;
    struct fuse         *m_fuse;
    struct fuse_session *m_fuse_session;
    QSocketNotifier     *m_notifier;
    QMutex              m_mutex;

    QSqlDatabase        &m_database;
    int                 m_profileId;
    QString             m_gameDataDir;
    QString             m_sandboxDir;
    QString             m_mountpoint;

    QList< FuseAccessorBase * > m_accessors;
    QList< FuseFHBase * >       m_open_handles;

    QStringList                         m_deleted;
    QMap< QString, QStringList >        m_dircache;
    QMap<QString, struct stat *>        m_cache_stat;
    QMap<QString, FuseAccessorBase *>   m_cache_accessor;
    QCache<QString, QSharedPointer<QByteArray>> m_cache_data;
    QFileSystemWatcher                  m_watcher;
    QHash< QString, VFSStatEntry >      m_stats;

    QMap< qint64, FuseFHBase * >        m_cow_redirects;

public:
    explicit FuseInterface(QSqlDatabase &database, int profileId, const QString &gameDataDir, const QString &sandboxDir, const QString &mountpoint, QObject *parent=nullptr);
    ~FuseInterface();

    Q_INVOKABLE bool mount();
    Q_INVOKABLE int pump();
    Q_INVOKABLE void unmount();

    Q_INVOKABLE void clear();
    Q_INVOKABLE void prepend(FuseAccessorBase *accessor);
    Q_INVOKABLE void append(FuseAccessorBase *accessor);
    Q_INVOKABLE void remove(FuseAccessorBase *accessor);

    QSqlDatabase &getDatabase() { return m_database; }
    int getProfileId() { return m_profileId; }

    //int utilQPermsToMode(QFileDevice::Permissions perms);
    FuseFHBase *getFH(struct fuse_file_info *fi);
    FuseFHBase *makeWritableFromSource(struct fuse_file_info *fi, const QString &source, const QString &origsource, const QString &dest, QIODeviceBase::OpenMode mode);
    FuseFHBase *makeWritableFromData(struct fuse_file_info *fi, const QByteArray &source, const QString &origsource, const QString &dest, QIODeviceBase::OpenMode mode);

    void cacheInsert(FuseAccessorBase *fab, const QString &path, const QByteArray &data);
    //QByteArray cacheGrab(const QString &path);
    QSharedPointer<QByteArray> cacheGrab(const QString &path);
    void cacheInvalidate(const QString &path);

    bool markDeleted(const QString &path, bool isdeleted=true);
    void readDeleted();

protected:
    void init();

    // FUSE stuff:
    int getattr(const char *path, struct stat *stbuf, struct fuse_file_info *fi);
    int create(const char *path, mode_t mode, struct fuse_file_info *fi);
    int mkdir(const char *path, mode_t mode);
    int unlink(const char *path);
    int rmdir(const char *path);
    int rename(const char *path, const char *newname, unsigned int flags);
    int truncate(const char *path, off_t offset, struct fuse_file_info *fi);
    int readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi, enum fuse_readdir_flags flags);
    int write(const char *path, const char *buf, size_t bufsz, off_t offset, struct fuse_file_info *fi);
    int open(const char *path, struct fuse_file_info *fi);
    int release(const char *path, struct fuse_file_info *fi);
    int read(const char *path, char *buf, size_t size, off_t offset, struct fuse_file_info *fi);
    off_t lseek(const char *path, off_t off, int whence, struct fuse_file_info *fi);

    // FUSE hooks:
    static int f_getattr(const char *path, struct stat *stbuf,
                struct fuse_file_info *fi);
    static int f_create(const char *path, mode_t mode, struct fuse_file_info *fi);
    static int f_mkdir(const char *path, mode_t mode);
    static int f_unlink(const char *path);
    static int f_rmdir(const char *path);
    static int f_rename(const char *path, const char *newname, unsigned int flags);
    static int f_truncate(const char *path, off_t offset, struct fuse_file_info *fi);
    static int f_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
                off_t offset, struct fuse_file_info *fi,
                enum fuse_readdir_flags flags);
    static int f_write(const char *path, const char *buf, size_t bufsz, off_t offset,
              struct fuse_file_info *fi);
    static int f_open(const char *path, struct fuse_file_info *fi);
    static int f_release(const char *path, struct fuse_file_info *fi);
    static int f_read(const char *path, char *buf, size_t size, off_t offset,
             struct fuse_file_info *fi);
    static off_t f_lseek(const char *path, off_t off, int whence, struct fuse_file_info *fi);

signals:
    void entryUpdated(const QString &path, qint8 type, const QString &facility, quint32 count, quint8 refcount);
};

Q_DECLARE_METATYPE(FuseInterface *)

#endif // FUSEINTERFACE_H