cpython/Python/thread_nt.h

/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the names of Stichting Mathematisch
Centrum or CWI or Corporation for National Research Initiatives or
CNRI not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.

While CWI is the initial source for this software, a modified version
is made available by the Corporation for National Research Initiatives
(CNRI) at the Internet address ftp://ftp.python.org.

STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

/* This code implemented by Dag.Gruneau@elsa.preseco.comm.se */

#include <windows.h>
#include <limits.h>
#include <process.h>

long get_thread_ident(void);

/*
 * Change all headers to pure ANSI as no one will use K&R style on an
 * NT
 */

/*
 * Initialization of the C package, should not be needed.
 */
static void _init_thread(void)
{
}

/*
 * Thread support.
 */
int start_new_thread(void (*func)(void *), void *arg)
{
	long rv;
	int success = 0;

	dprintf(("%ld: start_new_thread called\n", get_thread_ident()));
	if (!initialized)
		init_thread();

	rv = _beginthread(func, 0, arg); /* use default stack size */
 
	if (rv != -1) {
		success = 1;
		dprintf(("%ld: start_new_thread succeeded: %ld\n", get_thread_ident(), aThreadId));
	}

	return success;
}

/*
 * Return the thread Id instead of an handle. The Id is said to uniquely identify the
 * thread in the system
 */
long get_thread_ident(void)
{
	if (!initialized)
		init_thread();
        
	return GetCurrentThreadId();
}

static void do_exit_thread(int no_cleanup)
{
	dprintf(("%ld: exit_thread called\n", get_thread_ident()));
	if (!initialized)
		if (no_cleanup)
			_exit(0);
		else
			exit(0);
	_endthread();
}

void exit_thread(void)
{
	do_exit_thread(0);
}

void _exit_thread(void)
{
	do_exit_thread(1);
}

#ifndef NO_EXIT_PROG
static void do_exit_prog(int status, int no_cleanup)
{
	dprintf(("exit_prog(%d) called\n", status));
	if (!initialized)
		if (no_cleanup)
			_exit(status);
		else
			exit(status);
}

void exit_prog(int status)
{
	do_exit_prog(status, 0);
}

void _exit_prog _P1(int status)
{
	do_exit_prog(status, 1);
}
#endif /* NO_EXIT_PROG */

/*
 * Lock support. It has too be implemented as semaphores.
 * I [Dag] tried to implement it with mutex but I could find a way to
 * tell whether a thread already own the lock or not.
 */
type_lock allocate_lock(void)
{
	HANDLE aLock;

	dprintf(("allocate_lock called\n"));
	if (!initialized)
		init_thread();

		aLock = CreateSemaphore(NULL,           /* Security attributes          */
                         1,                     /* Initial value                */
                         1,                     /* Maximum value                */
                         NULL);       
  /* Name of semaphore            */

	dprintf(("%ld: allocate_lock() -> %lx\n", get_thread_ident(), (long)aLock));

	return (type_lock) aLock;
}

void free_lock(type_lock aLock)
{
	dprintf(("%ld: free_lock(%lx) called\n", get_thread_ident(),(long)aLock));

	CloseHandle((HANDLE) aLock);
}

/*
 * Return 1 on success if the lock was acquired
 *
 * and 0 if the lock was not acquired. This means a 0 is returned
 * if the lock has already been acquired by this thread!
 */
int acquire_lock(type_lock aLock, int waitflag)
{
	int success = 1;
	DWORD waitResult;

	dprintf(("%ld: acquire_lock(%lx, %d) called\n", get_thread_ident(),(long)aLock, waitflag));

	waitResult = WaitForSingleObject((HANDLE) aLock, (waitflag == 1 ? INFINITE : 0));

	if (waitResult != WAIT_OBJECT_0) {
		success = 0;    /* We failed */
	}

	dprintf(("%ld: acquire_lock(%lx, %d) -> %d\n", get_thread_ident(),(long)aLock, waitflag, success));

	return success;
}

void release_lock(type_lock aLock)
{
	dprintf(("%ld: release_lock(%lx) called\n", get_thread_ident(),(long)aLock));

	if (!ReleaseSemaphore(
                        (HANDLE) aLock,                         /* Handle of semaphore                          */
                        1,                                      /* increment count by one                       */
                        NULL))                                  /* not interested in previous count             */
		{
		dprintf(("%ld: Could not release_lock(%lx) error: %l\n", get_thread_ident(), (long)aLock, GetLastError()));
		}
}

/*
 * Semaphore support.
 */
type_sema allocate_sema(int value)
{
	HANDLE aSemaphore;

	dprintf(("%ld: allocate_sema called\n", get_thread_ident()));
	if (!initialized)
		init_thread();

	aSemaphore = CreateSemaphore( NULL,           /* Security attributes          */
                                  value,          /* Initial value                */
                                  INT_MAX,        /* Maximum value                */
                                  NULL);          /* Name of semaphore            */

	dprintf(("%ld: allocate_sema() -> %lx\n", get_thread_ident(), (long)aSemaphore));

	return (type_sema) aSemaphore;
}

void free_sema(type_sema aSemaphore)
{
	dprintf(("%ld: free_sema(%lx) called\n", get_thread_ident(), (long)aSemaphore));

	CloseHandle((HANDLE) aSemaphore);
}

/*
  XXX must do something about waitflag
 */
int down_sema(type_sema aSemaphore, int waitflag)
{
	DWORD waitResult;

	dprintf(("%ld: down_sema(%lx) called\n", get_thread_ident(), (long)aSemaphore));

	waitResult = WaitForSingleObject( (HANDLE) aSemaphore, INFINITE);

	dprintf(("%ld: down_sema(%lx) return: %l\n", get_thread_ident(),(long) aSemaphore, waitResult));
	return 0;
}

void up_sema(type_sema aSemaphore)
{
	ReleaseSemaphore(
                (HANDLE) aSemaphore,            /* Handle of semaphore                          */
                1,                              /* increment count by one                       */
                NULL);                          /* not interested in previous count             */
                                                
	dprintf(("%ld: up_sema(%lx)\n", get_thread_ident(), (long)aSemaphore));
}