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
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permission.

While CWI is the initial source for this software, a modified version
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(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
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******************************************************************/

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

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

long PyThread_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 PyThread__init_thread(void)
{
}

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

	dprintf(("%ld: PyThread_start_new_thread called\n", PyThread_get_thread_ident()));
	if (!initialized)
		PyThread_init_thread();

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

	return success;
}

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

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

void PyThread_exit_thread(void)
{
	do_PyThread_exit_thread(0);
}

void PyThread__exit_thread(void)
{
	do_PyThread_exit_thread(1);
}

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

void PyThread_exit_prog(int status)
{
	do_PyThread_exit_prog(status, 0);
}

void PyThread__exit_prog _P1(int status)
{
	do_PyThread_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.
 */
PyThread_type_lock PyThread_allocate_lock(void)
{
	HANDLE aLock;

	dprintf(("PyThread_allocate_lock called\n"));
	if (!initialized)
		PyThread_init_thread();

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

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

	return (PyThread_type_lock) aLock;
}

void PyThread_free_lock(PyThread_type_lock aLock)
{
	dprintf(("%ld: PyThread_free_lock(%lx) called\n", PyThread_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 PyThread_acquire_lock(PyThread_type_lock aLock, int waitflag)
{
	int success = 1;
	DWORD waitResult;

	dprintf(("%ld: PyThread_acquire_lock(%lx, %d) called\n", PyThread_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: PyThread_acquire_lock(%lx, %d) -> %d\n", PyThread_get_thread_ident(),(long)aLock, waitflag, success));

	return success;
}

void PyThread_release_lock(PyThread_type_lock aLock)
{
	dprintf(("%ld: PyThread_release_lock(%lx) called\n", PyThread_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 PyThread_release_lock(%lx) error: %l\n", PyThread_get_thread_ident(), (long)aLock, GetLastError()));
		}
}

/*
 * Semaphore support.
 */
PyThread_type_sema PyThread_allocate_sema(int value)
{
	HANDLE aSemaphore;

	dprintf(("%ld: PyThread_allocate_sema called\n", PyThread_get_thread_ident()));
	if (!initialized)
		PyThread_init_thread();

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

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

	return (PyThread_type_sema) aSemaphore;
}

void PyThread_free_sema(PyThread_type_sema aSemaphore)
{
	dprintf(("%ld: PyThread_free_sema(%lx) called\n", PyThread_get_thread_ident(), (long)aSemaphore));

	CloseHandle((HANDLE) aSemaphore);
}

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

	dprintf(("%ld: PyThread_down_sema(%lx) called\n", PyThread_get_thread_ident(), (long)aSemaphore));

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

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

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