xref: /xsrc/external/mit/libX11/dist/src/locking.h

/*

Copyright 1992, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

*/

/*
 * Author: Stephen Gildea, MIT X Consortium
 *
 * locking.h - data types for C Threads locking.
 * Used by XlibInt.c, locking.c, LockDis.c
 */

#ifndef _X_locking_H_
#define _X_locking_H_

#ifndef xmalloc
#define xmalloc(s) Xmalloc(s)
#endif
#ifndef xfree
#define xfree(s) Xfree(s)
#endif
#include <X11/Xlib.h>
#include <X11/Xlibint.h>
#include <X11/Xthreads.h>

struct _XCVList {
    xcondition_t cv;
    xReply *buf;
    struct _XCVList *next;
};

extern xthread_t (*_Xthread_self_fn)( /* in XlibInt.c */
    void
);

/* Display->lock is a pointer to one of these */

struct _XLockInfo {
	xmutex_t mutex;		/* mutex for critical sections */
	int reply_bytes_left;	/* nbytes of the reply still to read */
	Bool reply_was_read;	/* _XReadEvents read a reply for _XReply */
	struct _XCVList *reply_awaiters; /* list of CVs for _XReply */
	struct _XCVList **reply_awaiters_tail;
	struct _XCVList *event_awaiters; /* list of CVs for _XReadEvents */
	struct _XCVList **event_awaiters_tail;
	Bool reply_first;	/* who may read, reply queue or event queue */
	/* for XLockDisplay */
	int locking_level;	/* how many times into XLockDisplay we are */
	xthread_t locking_thread; /* thread that did XLockDisplay */
	xcondition_t cv;	/* wait if another thread has XLockDisplay */
	xthread_t reading_thread; /* cache */
	xthread_t conni_thread;	/* thread in XProcessInternalConnection */
	xcondition_t writers;	/* wait for writable */
	int num_free_cvls;
	struct _XCVList *free_cvls;
	/* used only in XlibInt.c */
	void (*pop_reader)(
			   Display* /* dpy */,
			   struct _XCVList** /* list */,
			   struct _XCVList*** /* tail */
			   );
	struct _XCVList *(*push_reader)(
					Display *	   /* dpy */,
					struct _XCVList*** /* tail */
					);
	void (*condition_wait)(
			       xcondition_t /* cv */,
			       xmutex_t /* mutex */
#if defined(XTHREADS_WARN) || defined(XTHREADS_FILE_LINE)
			       , char* /* file */,
			       int /* line */
#endif
			       );
	void (*internal_lock_display)(
				      Display* /* dpy */,
				      Bool /* wskip */
#if defined(XTHREADS_WARN) || defined(XTHREADS_FILE_LINE)
				      , char* /* file */,
				      int /* line */
#endif
				      );
	/* used in XlibInt.c and locking.c */
	void (*condition_signal)(
				 xcondition_t /* cv */
#if defined(XTHREADS_WARN) || defined(XTHREADS_FILE_LINE)
				 , char* /* file */,
				 int /* line */
#endif
				 );
	void (*condition_broadcast)(
				 xcondition_t /* cv */
#if defined(XTHREADS_WARN) || defined(XTHREADS_FILE_LINE)
				 , char* /* file */,
				 int /* line */
#endif
				    );
	/* used in XlibInt.c and XLockDis.c */
	void (*lock_wait)(
			  Display* /* dpy */
			  );
	void (*user_lock_display)(
				  Display* /* dpy */
				  );
	void (*user_unlock_display)(
				    Display* /* dpy */
				    );
	struct _XCVList *(*create_cvl)(
				       Display * /* dpy */
				       );
};

#define UnlockNextEventReader(d) if ((d)->lock) \
    (*(d)->lock->pop_reader)((d),&(d)->lock->event_awaiters,&(d)->lock->event_awaiters_tail)

#if defined(XTHREADS_WARN) || defined(XTHREADS_FILE_LINE)
#define ConditionWait(d,c) if ((d)->lock) \
	(*(d)->lock->condition_wait)(c, (d)->lock->mutex,__FILE__,__LINE__)
#define ConditionSignal(d,c) if ((d)->lock) \
	(*(d)->lock->condition_signal)(c,__FILE__,__LINE__)
#define ConditionBroadcast(d,c) if ((d)->lock) \
	(*(d)->lock->condition_broadcast)(c,__FILE__,__LINE__)
#else
#define ConditionWait(d,c) if ((d)->lock) \
	(*(d)->lock->condition_wait)(c, (d)->lock->mutex)
#define ConditionSignal(d,c) if ((d)->lock) \
	(*(d)->lock->condition_signal)(c)
#define ConditionBroadcast(d,c) if ((d)->lock) \
	(*(d)->lock->condition_broadcast)(c)
#endif

typedef struct _LockInfoRec {
	xmutex_t	lock;
} LockInfoRec;

/* A list of threads currently invoking error handlers on this display
 * LockDisplay operates differently for these threads, avoiding
 * generating any requests or reading any events as that can cause
 * recursion into the error handling code, which will deadlock the
 * thread.
 */
struct _XErrorThreadInfo
{
    struct _XErrorThreadInfo *next;
    xthread_t error_thread;
};

/* XOpenDis.c */
extern int (*_XInitDisplayLock_fn)(Display *dpy);
extern void (*_XFreeDisplayLock_fn)(Display *dpy);

#endif /* _X_locking_H_ */