newlib-cygwin/winsup/cygwin/select.h

/* select.h

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#ifndef _SELECT_H_
#define _SELECT_H_

struct fh_select_data_serial
{
  DWORD event;
  OVERLAPPED ov;

  fh_select_data_serial () : event (0) { memset (&ov, 0, sizeof ov); }
};

struct select_record
{
  int fd;
  HANDLE h;
  fhandler_base *fh;
  _cygtls *tls;
  int thread_errno;
  bool windows_handle;
  bool read_ready, write_ready, except_ready;
  bool read_selected, write_selected, except_selected;
  bool except_on_write;
  int (*startup) (select_record *, class select_stuff *);
  int (*peek) (select_record *, bool);
  int (*verify) (select_record *, fd_set *, fd_set *, fd_set *);
  void (*cleanup) (select_record *, class select_stuff *);
  struct select_record *next;
  /* If an fhandler type needs per-fhandler, per-select data, this union
     is the place to add it.  First candidate: fhandler_serial. */
  union
  {
    fh_select_data_serial *fh_data_serial;
    void *fh_data_union; /* type-agnostic placeholder for constructor */
  };
  void set_select_errno () {__seterrno (); thread_errno = errno;}
  int saw_error () {return thread_errno;}
  select_record (int): next (NULL) {}
  select_record () :
    fd (0), h (NULL), fh (NULL), tls (&_my_tls), thread_errno (0),
    windows_handle (false), read_ready (false), write_ready (false),
    except_ready (false), read_selected (false), write_selected (false),
    except_selected (false), except_on_write (false),
    startup (NULL), peek (NULL), verify (NULL), cleanup (NULL),
    next (NULL), fh_data_union (NULL) {}
#ifdef DEBUGGING
  void dump_select_record ();
#endif
};

struct select_info
{
  cygthread *thread;
  bool stop_thread;
  HANDLE bye;
  select_record *start;
  select_info (): thread (NULL), stop_thread (0), start (NULL) {}
};

struct select_pipe_info: public select_info
{
  select_pipe_info (): select_info () {}
};

struct select_fifo_info: public select_info
{
  select_fifo_info (): select_info () {}
};

struct select_socket_info: public select_info
{
  int num_w4;
  LONG *ser_num;
  HANDLE *w4;
  select_socket_info (): select_info (), num_w4 (0), ser_num (0), w4 (NULL) {}
};

class select_stuff
{
public:
  enum wait_states
  {
    select_signalled = -3,
    select_error = -1,
    select_ok = 0,
    select_set_zero = 1
  };

  ~select_stuff ();
  bool return_on_signal;
  bool always_ready, windows_used;
  select_record start;

  /* If an fhandler type needs a singleton per-select datastructure for all
     its objects in the descriptor lists, here's the place to be.  This is
     mainly used to maintain a single thread for all fhandlers of a single
     type in the descriptor lists. */
  select_pipe_info *device_specific_pipe;
  select_pipe_info *device_specific_ptys;
  select_fifo_info *device_specific_fifo;
  select_socket_info *device_specific_socket;

  bool test_and_set (int, fd_set *, fd_set *, fd_set *);
  int poll (fd_set *, fd_set *, fd_set *);
  wait_states wait (fd_set *, fd_set *, fd_set *, LONGLONG);
  void cleanup ();
  void destroy ();

  select_stuff (): return_on_signal (false), always_ready (false),
		   windows_used (false), start (),
		   device_specific_pipe (NULL),
		   device_specific_ptys (NULL),
		   device_specific_fifo (NULL),
		   device_specific_socket (NULL)
		   {}
};

extern "C" int cygwin_select (int , fd_set *, fd_set *, fd_set *,
			      struct timeval *to);

#endif /* _SELECT_H_ */