/* 
 * tclWinThread.c --
 *
 *	This file implements the Windows-specific thread operations.
 *
 * Copyright (c) 1998 by Sun Microsystems, Inc.
 * Copyright (c) 1999 by Scriptics Corporation
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclWinThrd.c,v 1.9 2000/05/02 22:02:38 kupries Exp $
 */

#include "tclWinInt.h"

#include <dos.h>
#include <fcntl.h>
#include <io.h>

 * allocLock is used by Tcl's version of malloc for synchronization.
 * For obvious reasons, cannot use any dyamically allocated storage.
 */

static CRITICAL_SECTION allocLock;
static Tcl_Mutex allocLockPtr = (Tcl_Mutex) &allocLock;

/*
 * The joinLock serializes Create- and ExitThread. This is necessary to
 * prevent a race where a new joinable thread exits before the creating
 * thread had the time to create the necessary data structures in the
 * emulation layer.
 */

static CRITICAL_SECTION joinLock;

/*
 * Condition variables are implemented with a combination of a 
 * per-thread Windows Event and a per-condition waiting queue.
 * The idea is that each thread has its own Event that it waits
 * on when it is doing a ConditionWait; it uses the same event for
 * all condition variables because it only waits on one at a time.
 * Each condition variable has a queue of waiting threads, and a 

    Tcl_ThreadCreateProc proc;		/* Main() function of the thread */
    ClientData clientData;		/* The one argument to Main() */
    int stackSize;			/* Size of stack for the new thread */
    int flags;				/* Flags controlling behaviour of
					 * the new thread */
{
    unsigned long code;

    EnterCriticalSection(&joinLock);

    code = _beginthreadex(NULL, stackSize, proc, clientData, 0,
	(unsigned *)idPtr);

    if (code == 0) {
        LeaveCriticalSection(&joinLock);
	return TCL_ERROR;
    } else {
        if (flags & TCL_THREAD_JOINABLE) {
	    TclRememberJoinableThread (*idPtr);
	}

	LeaveCriticalSection(&joinLock);
	return TCL_OK;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_JoinThread --
 *
 *	This procedure waits upon the exit of the specified thread.
 *
 * Results:
 *	TCL_OK if the wait was successful, TCL_ERROR else.
 *
 * Side effects:
 *	The result area is set to the exit code of the thread we
 *	waited upon.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_JoinThread(id, result)
    Tcl_ThreadId id;	/* Id of the thread to wait upon */
    int*     result;	/* Reference to the storage the result
			 * of the thread we wait upon will be
			 * written into. */
{
    return TclJoinThread (id, result);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpThreadExit --
 *
 *	This procedure terminates the current thread.

 *----------------------------------------------------------------------
 */

void
TclpThreadExit(status)
    int status;
{
    EnterCriticalSection(&joinLock);
    TclSignalExitThread (Tcl_GetCurrentThread (), status);
    LeaveCriticalSection(&joinLock);

    _endthreadex((DWORD)status);
}


/*
 *----------------------------------------------------------------------
 *


/*
 *----------------------------------------------------------------------
 *
 * Tcl_ConditionWait --
 *
 *	This procedure is invoked to wait on a condition variable.
 *	The mutex is atomically released as part of the wait, and
 *	automatically grabbed when the condition is signaled.
 *
 *	The mutex must be held when this procedure is called.
 *
 * Results:
 *	None.
 *

	 * No more per-thread event on which to wait.
	 */

	return;
    }

    /*
     * Self initialize the two parts of the condition.
     * The per-condition and per-thread parts need to be
     * handled independently.
     */

    if (tsdPtr->flags == WIN_THREAD_UNINIT) {
	MASTER_LOCK;

	    doExit = 1;
	}
	MASTER_UNLOCK;

	if (doExit) {
	    /*
	     * Create a per-thread exit handler to clean up the condEvent.
	     * We must be careful to do this outside the Master Lock
	     * because Tcl_CreateThreadExitHandler uses its own
	     * ThreadSpecificData, and initializing that may drop
	     * back into the Master Lock.
	     */
	    
	    Tcl_CreateThreadExitHandler(FinalizeConditionEvent,
		    (ClientData) tsdPtr);