CDev.hpp

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#ifndef _CDEV_HPP
#define _CDEV_HPP

#include <px4_config.h>
#include <px4_posix.h>

#ifdef __PX4_NUTTX
#include "nuttx/cdev_platform.hpp"
#else
#include "posix/cdev_platform.hpp"
#endif

namespace cdev
{

class __EXPORT CDev
{
public:
    CDev(const char *devname);

    virtual ~CDev();

    virtual int init();

    virtual int open(file_t *filep);

    virtual int close(file_t *filep);

    virtual ssize_t read(file_t *filep, char *buffer, size_t buflen) { return -ENOSYS; }

    virtual ssize_t write(file_t *filep, const char *buffer, size_t buflen) { return -ENOSYS; }

    virtual off_t   seek(file_t *filep, off_t offset, int whence) { return -ENOSYS; }

    virtual int ioctl(file_t *filep, int cmd, unsigned long arg);

    virtual int poll(file_t *filep, px4_pollfd_struct_t *fds, bool setup);

    const char  *get_devname() const { return _devname; }

protected:
    static const px4_file_operations_t  fops;

    virtual pollevent_t poll_state(file_t *filep) { return 0; }

    virtual void    poll_notify(pollevent_t events);

    virtual void    poll_notify_one(px4_pollfd_struct_t *fds, pollevent_t events);

    virtual int open_first(file_t *filep) { return PX4_OK; }

    virtual int close_last(file_t *filep) { return PX4_OK; }

    virtual int register_class_devname(const char *class_devname);

    virtual int unregister_class_devname(const char *class_devname, unsigned class_instance);

    void        lock() { do {} while (px4_sem_wait(&_lock) != 0); }

    void        unlock() { px4_sem_post(&_lock); }

    px4_sem_t   _lock; 
private:
    const char  *_devname{nullptr};     
    px4_pollfd_struct_t **_pollset{nullptr};

    bool        _registered{false};     
    uint8_t     _max_pollwaiters{0};        
    uint16_t    _open_count{0};         
    inline int  store_poll_waiter(px4_pollfd_struct_t *fds);

    inline int  remove_poll_waiter(px4_pollfd_struct_t *fds);

    /* do not allow copying this class */
    CDev(const CDev &);
    CDev operator=(const CDev &);
};

} // namespace cdev

#endif /* _CDEV_HPP */