summaryrefslogtreecommitdiffstats
path: root/win/tclWinThrd.c
blob: 6ee0a5e84cd1c2ce88826364e9d827edc7b92fd0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
/*
 * tclWinThread.c --
 *
 *	This file implements the Windows-specific thread operations.
 *
 * Copyright (c) 1998 by Sun Microsystems, Inc.
 * Copyright (c) 1999 by Scriptics Corporation
 * Copyright (c) 2008 by George Peter Staplin
 *
 * 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 1.46 2008/06/13 05:45:15 mistachkin Exp $
 */

#include "tclWinInt.h"

#include <fcntl.h>
#include <io.h>
#include <sys/stat.h>

/*
 * This is the master lock used to serialize access to other serialization
 * data structures.
 */

static CRITICAL_SECTION masterLock;
static int init = 0;
#define MASTER_LOCK TclpMasterLock()
#define MASTER_UNLOCK TclpMasterUnlock()


/*
 * This is the master lock used to serialize initialization and finalization
 * of Tcl as a whole.
 */

static CRITICAL_SECTION initLock;

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

#ifdef TCL_THREADS

static CRITICAL_SECTION allocLock;
static Tcl_Mutex allocLockPtr = (Tcl_Mutex) &allocLock;
static int allocOnce = 0;

#endif /* TCL_THREADS */

/*
 * 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 mutex used to serialize access to this queue.
 *
 * Special thanks to David Nichols and Jim Davidson for advice on the
 * Condition Variable implementation.
 */

/*
 * The per-thread event and queue pointers.
 */

#ifdef TCL_THREADS

typedef struct ThreadSpecificData {
    HANDLE condEvent;			/* Per-thread condition event */
    struct ThreadSpecificData *nextPtr;	/* Queue pointers */
    struct ThreadSpecificData *prevPtr;
    int flags;				/* See flags below */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

#endif /* TCL_THREADS */

/*
 * State bits for the thread.
 * WIN_THREAD_UNINIT		Uninitialized. Must be zero because of the way
 *				ThreadSpecificData is created.
 * WIN_THREAD_RUNNING		Running, not waiting.
 * WIN_THREAD_BLOCKED		Waiting, or trying to wait.
 */

#define WIN_THREAD_UNINIT	0x0
#define WIN_THREAD_RUNNING	0x1
#define WIN_THREAD_BLOCKED	0x2

/*
 * The per condition queue pointers and the Mutex used to serialize access to
 * the queue.
 */

typedef struct WinCondition {
    CRITICAL_SECTION condLock;	/* Lock to serialize queuing on the
				 * condition. */
    struct ThreadSpecificData *firstPtr;	/* Queue pointers */
    struct ThreadSpecificData *lastPtr;
} WinCondition;

/*
 * Additions by AOL for specialized thread memory allocator.
 */

#ifdef USE_THREAD_ALLOC
static int once;
static DWORD tlsKey;

typedef struct allocMutex {
    Tcl_Mutex	     tlock;
    CRITICAL_SECTION wlock;
} allocMutex;
#endif /* USE_THREAD_ALLOC */

/*
 *----------------------------------------------------------------------
 *
 * TclpThreadCreate --
 *
 *	This procedure creates a new thread.
 *
 * Results:
 *	TCL_OK if the thread could be created. The thread ID is returned in a
 *	parameter.
 *
 * Side effects:
 *	A new thread is created.
 *
 *----------------------------------------------------------------------
 */

int
TclpThreadCreate(
    Tcl_ThreadId *idPtr,	/* Return, the ID of the thread. */
    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. */
{
    HANDLE tHandle;

    EnterCriticalSection(&joinLock);

#if defined(_MSC_VER) || defined(__MSVCRT__) || defined(__BORLANDC__)
    tHandle = (HANDLE) _beginthreadex(NULL, (unsigned) stackSize, proc,
	    clientData, 0, (unsigned *)idPtr);
#else
    tHandle = CreateThread(NULL, (DWORD) stackSize,
	    (LPTHREAD_START_ROUTINE) proc, (LPVOID) clientData,
	    (DWORD) 0, (LPDWORD)idPtr);
#endif

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

	/*
	 * The only purpose of this is to decrement the reference count so the
	 * OS resources will be reaquired when the thread closes.
	 */

	CloseHandle(tHandle);
	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(
    Tcl_ThreadId threadId,	/* 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(threadId, result);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpThreadExit --
 *
 *	This procedure terminates the current thread.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	This procedure terminates the current thread.
 *
 *----------------------------------------------------------------------
 */

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

#if defined(_MSC_VER) || defined(__MSVCRT__) || defined(__BORLANDC__)
    _endthreadex((unsigned) status);
#else
    ExitThread((DWORD) status);
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetCurrentThread --
 *
 *	This procedure returns the ID of the currently running thread.
 *
 * Results:
 *	A thread ID.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_ThreadId
Tcl_GetCurrentThread(void)
{
    return (Tcl_ThreadId) GetCurrentThreadId();
}

/*
 *----------------------------------------------------------------------
 *
 * TclpInitLock
 *
 *	This procedure is used to grab a lock that serializes initialization
 *	and finalization of Tcl. On some platforms this may also initialize
 *	the mutex used to serialize creation of more mutexes and thread local
 *	storage keys.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Acquire the initialization mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpInitLock(void)
{
    if (!init) {
	/*
	 * There is a fundamental race here that is solved by creating the
	 * first Tcl interpreter in a single threaded environment. Once the
	 * interpreter has been created, it is safe to create more threads
	 * that create interpreters in parallel.
	 */

	init = 1;
	InitializeCriticalSection(&joinLock);
	InitializeCriticalSection(&initLock);
	InitializeCriticalSection(&masterLock);
    }
    EnterCriticalSection(&initLock);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpInitUnlock
 *
 *	This procedure is used to release a lock that serializes
 *	initialization and finalization of Tcl.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Release the initialization mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpInitUnlock(void)
{
    LeaveCriticalSection(&initLock);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpMasterLock
 *
 *	This procedure is used to grab a lock that serializes creation of
 *	mutexes, condition variables, and thread local storage keys.
 *
 *	This lock must be different than the initLock because the initLock is
 *	held during creation of syncronization objects.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Acquire the master mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpMasterLock(void)
{
    if (!init) {
	/*
	 * There is a fundamental race here that is solved by creating the
	 * first Tcl interpreter in a single threaded environment. Once the
	 * interpreter has been created, it is safe to create more threads
	 * that create interpreters in parallel.
	 */

	init = 1;
	InitializeCriticalSection(&joinLock);
	InitializeCriticalSection(&initLock);
	InitializeCriticalSection(&masterLock);
    }
    EnterCriticalSection(&masterLock);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpMasterUnlock
 *
 *	This procedure is used to release a lock that serializes creation and
 *	deletion of synchronization objects.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Release the master mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpMasterUnlock(void)
{
    LeaveCriticalSection(&masterLock);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetAllocMutex
 *
 *	This procedure returns a pointer to a statically initialized mutex for
 *	use by the memory allocator. The alloctor must use this lock, because
 *	all other locks are allocated...
 *
 * Results:
 *	A pointer to a mutex that is suitable for passing to Tcl_MutexLock and
 *	Tcl_MutexUnlock.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_Mutex *
Tcl_GetAllocMutex(void)
{
#ifdef TCL_THREADS
    if (!allocOnce) {
	InitializeCriticalSection(&allocLock);
	allocOnce = 1;
    }
    return &allocLockPtr;
#else
    return NULL;
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * TclpFinalizeLock
 *
 *	This procedure is used to destroy all private resources used in this
 *	file.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Destroys everything private. TclpInitLock must be held entering this
 *	function.
 *
 *----------------------------------------------------------------------
 */

void
TclFinalizeLock(void)
{
    MASTER_LOCK;
    DeleteCriticalSection(&joinLock);

    /*
     * Destroy the critical section that we are holding!
     */

    DeleteCriticalSection(&masterLock);
    init = 0;

#ifdef TCL_THREADS
    if (allocOnce) {
	DeleteCriticalSection(&allocLock);
	allocOnce = 0;
    }
#endif

    LeaveCriticalSection(&initLock);

    /*
     * Destroy the critical section that we were holding.
     */

    DeleteCriticalSection(&initLock);
}

#ifdef TCL_THREADS

/* locally used prototype */
static void		FinalizeConditionEvent(ClientData data);

/*
 *----------------------------------------------------------------------
 *
 * Tcl_MutexLock --
 *
 *	This procedure is invoked to lock a mutex. This is a self initializing
 *	mutex that is automatically finalized during Tcl_Finalize.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May block the current thread. The mutex is aquired when this returns.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_MutexLock(
    Tcl_Mutex *mutexPtr)	/* The lock */
{
    CRITICAL_SECTION *csPtr;
    if (*mutexPtr == NULL) {
	MASTER_LOCK;

	/*
	 * Double inside master lock check to avoid a race.
	 */

	if (*mutexPtr == NULL) {
	    csPtr = (CRITICAL_SECTION *) ckalloc(sizeof(CRITICAL_SECTION));
	    InitializeCriticalSection(csPtr);
	    *mutexPtr = (Tcl_Mutex)csPtr;
	    TclRememberMutex(mutexPtr);
	}
	MASTER_UNLOCK;
    }
    csPtr = *((CRITICAL_SECTION **)mutexPtr);
    EnterCriticalSection(csPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_MutexUnlock --
 *
 *	This procedure is invoked to unlock a mutex.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The mutex is released when this returns.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_MutexUnlock(
    Tcl_Mutex *mutexPtr)	/* The lock */
{
    CRITICAL_SECTION *csPtr = *((CRITICAL_SECTION **)mutexPtr);
    LeaveCriticalSection(csPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpFinalizeMutex --
 *
 *	This procedure is invoked to clean up one mutex. This is only safe to
 *	call at the end of time.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The mutex list is deallocated.
 *
 *----------------------------------------------------------------------
 */

void
TclpFinalizeMutex(
    Tcl_Mutex *mutexPtr)
{
    CRITICAL_SECTION *csPtr = *(CRITICAL_SECTION **)mutexPtr;
    if (csPtr != NULL) {
	DeleteCriticalSection(csPtr);
	ckfree((char *) csPtr);
	*mutexPtr = NULL;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * 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.
 *
 * Side effects:
 *	May block the current thread. The mutex is aquired when this returns.
 *	Will allocate memory for a HANDLE and initialize this the first time
 *	this Tcl_Condition is used.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_ConditionWait(
    Tcl_Condition *condPtr,	/* Really (WinCondition **) */
    Tcl_Mutex *mutexPtr,	/* Really (CRITICAL_SECTION **) */
    Tcl_Time *timePtr)		/* Timeout on waiting period */
{
    WinCondition *winCondPtr;	/* Per-condition queue head */
    CRITICAL_SECTION *csPtr;	/* Caller's Mutex, after casting */
    DWORD wtime;		/* Windows time value */
    int timeout;		/* True if we got a timeout */
    int doExit = 0;		/* True if we need to do exit setup */
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    /*
     * 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;

	/*
	 * Create the per-thread event and queue pointers.
	 */

	if (tsdPtr->flags == WIN_THREAD_UNINIT) {
	    tsdPtr->condEvent = CreateEvent(NULL, TRUE /* manual reset */,
		    FALSE /* non signaled */, NULL);
	    tsdPtr->nextPtr = NULL;
	    tsdPtr->prevPtr = NULL;
	    tsdPtr->flags = WIN_THREAD_RUNNING;
	    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);
	}
    }

    if (*condPtr == NULL) {
	MASTER_LOCK;

	/*
	 * Initialize the per-condition queue pointers and Mutex.
	 */

	if (*condPtr == NULL) {
	    winCondPtr = (WinCondition *)ckalloc(sizeof(WinCondition));
	    InitializeCriticalSection(&winCondPtr->condLock);
	    winCondPtr->firstPtr = NULL;
	    winCondPtr->lastPtr = NULL;
	    *condPtr = (Tcl_Condition)winCondPtr;
	    TclRememberCondition(condPtr);
	}
	MASTER_UNLOCK;
    }
    csPtr = *((CRITICAL_SECTION **)mutexPtr);
    winCondPtr = *((WinCondition **)condPtr);
    if (timePtr == NULL) {
	wtime = INFINITE;
    } else {
	wtime = timePtr->sec * 1000 + timePtr->usec / 1000;
    }

    /*
     * Queue the thread on the condition, using the per-condition lock for
     * serialization.
     */

    tsdPtr->flags = WIN_THREAD_BLOCKED;
    tsdPtr->nextPtr = NULL;
    EnterCriticalSection(&winCondPtr->condLock);
    tsdPtr->prevPtr = winCondPtr->lastPtr;		/* A: */
    winCondPtr->lastPtr = tsdPtr;
    if (tsdPtr->prevPtr != NULL) {
	tsdPtr->prevPtr->nextPtr = tsdPtr;
    }
    if (winCondPtr->firstPtr == NULL) {
	winCondPtr->firstPtr = tsdPtr;
    }

    /*
     * Unlock the caller's mutex and wait for the condition, or a timeout.
     * There is a minor issue here in that we don't count down the timeout if
     * we get notified, but another thread grabs the condition before we do.
     * In that race condition we'll wait again for the full timeout. Timed
     * waits are dubious anyway. Either you have the locking protocol wrong
     * and are masking a deadlock, or you are using conditions to pause your
     * thread.
     */

    LeaveCriticalSection(csPtr);
    timeout = 0;
    while (!timeout && (tsdPtr->flags & WIN_THREAD_BLOCKED)) {
	ResetEvent(tsdPtr->condEvent);
	LeaveCriticalSection(&winCondPtr->condLock);
	if (WaitForSingleObjectEx(tsdPtr->condEvent, wtime, TRUE) == WAIT_TIMEOUT) {
	    timeout = 1;
	}
	EnterCriticalSection(&winCondPtr->condLock);
    }

    /*
     * Be careful on timeouts because the signal might arrive right around the
     * time limit and someone else could have taken us off the queue.
     */

    if (timeout) {
	if (tsdPtr->flags & WIN_THREAD_RUNNING) {
	    timeout = 0;
	} else {
	    /*
	     * When dequeuing, we can leave the tsdPtr->nextPtr and
	     * tsdPtr->prevPtr with dangling pointers because they are
	     * reinitialilzed w/out reading them when the thread is enqueued
	     * later.
	     */

	    if (winCondPtr->firstPtr == tsdPtr) {
		winCondPtr->firstPtr = tsdPtr->nextPtr;
	    } else {
		tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr;
	    }
	    if (winCondPtr->lastPtr == tsdPtr) {
		winCondPtr->lastPtr = tsdPtr->prevPtr;
	    } else {
		tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr;
	    }
	    tsdPtr->flags = WIN_THREAD_RUNNING;
	}
    }

    LeaveCriticalSection(&winCondPtr->condLock);
    EnterCriticalSection(csPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ConditionNotify --
 *
 *	This procedure is invoked to signal a condition variable.
 *
 *	The mutex must be held during this call to avoid races, but this
 *	interface does not enforce that.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May unblock another thread.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_ConditionNotify(
    Tcl_Condition *condPtr)
{
    WinCondition *winCondPtr;
    ThreadSpecificData *tsdPtr;
    if (*condPtr != NULL) {
	winCondPtr = *((WinCondition **)condPtr);

	if (winCondPtr == NULL) {
	    return;
	}

	/*
	 * Loop through all the threads waiting on the condition and notify
	 * them (i.e., broadcast semantics). The queue manipulation is guarded
	 * by the per-condition coordinating mutex.
	 */

	EnterCriticalSection(&winCondPtr->condLock);
	while (winCondPtr->firstPtr != NULL) {
	    tsdPtr = winCondPtr->firstPtr;
	    winCondPtr->firstPtr = tsdPtr->nextPtr;
	    if (winCondPtr->lastPtr == tsdPtr) {
		winCondPtr->lastPtr = NULL;
	    }
	    tsdPtr->flags = WIN_THREAD_RUNNING;
	    tsdPtr->nextPtr = NULL;
	    tsdPtr->prevPtr = NULL;	/* Not strictly necessary, see A: */
	    SetEvent(tsdPtr->condEvent);
	}
	LeaveCriticalSection(&winCondPtr->condLock);
    } else {
	/*
	 * No-one has used the condition variable, so there are no waiters.
	 */
    }
}

/*
 *----------------------------------------------------------------------
 *
 * FinalizeConditionEvent --
 *
 *	This procedure is invoked to clean up the per-thread event used to
 *	implement condition waiting. This is only safe to call at the end of
 *	time.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The per-thread event is closed.
 *
 *----------------------------------------------------------------------
 */

static void
FinalizeConditionEvent(
    ClientData data)
{
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *) data;
    tsdPtr->flags = WIN_THREAD_UNINIT;
    CloseHandle(tsdPtr->condEvent);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpFinalizeCondition --
 *
 *	This procedure is invoked to clean up a condition variable. This is
 *	only safe to call at the end of time.
 *
 *	This assumes the Master Lock is held.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The condition variable is deallocated.
 *
 *----------------------------------------------------------------------
 */

void
TclpFinalizeCondition(
    Tcl_Condition *condPtr)
{
    WinCondition *winCondPtr = *(WinCondition **)condPtr;

    /*
     * Note - this is called long after the thread-local storage is reclaimed.
     * The per-thread condition waiting event is reclaimed earlier in a
     * per-thread exit handler, which is called before thread local storage is
     * reclaimed.
     */

    if (winCondPtr != NULL) {
	DeleteCriticalSection(&winCondPtr->condLock);
	ckfree((char *) winCondPtr);
	*condPtr = NULL;
    }
}




/*
 * Additions by AOL for specialized thread memory allocator.
 */
#ifdef USE_THREAD_ALLOC

Tcl_Mutex *
TclpNewAllocMutex(void)
{
    struct allocMutex *lockPtr;

    lockPtr = malloc(sizeof(struct allocMutex));
    if (lockPtr == NULL) {
	Tcl_Panic("could not allocate lock");
    }
    lockPtr->tlock = (Tcl_Mutex) &lockPtr->wlock;
    InitializeCriticalSection(&lockPtr->wlock);
    return &lockPtr->tlock;
}

void
TclpFreeAllocMutex(
    Tcl_Mutex *mutex)		/* The alloc mutex to free. */
{
    allocMutex *lockPtr = (allocMutex *) mutex;

    if (!lockPtr) {
	return;
    }
    DeleteCriticalSection(&lockPtr->wlock);
    free(lockPtr);
}

void *
TclpGetAllocCache(void)
{
    void *result;

    if (!once) {
	/*
	 * We need to make sure that TclpFreeAllocCache is called on each
	 * thread that calls this, but only on threads that call this.
	 */

	tlsKey = TlsAlloc();
	once = 1;
	if (tlsKey == TLS_OUT_OF_INDEXES) {
	    Tcl_Panic("could not allocate thread local storage");
	}
    }

    result = TlsGetValue(tlsKey);
    if ((result == NULL) && (GetLastError() != NO_ERROR)) {
	Tcl_Panic("TlsGetValue failed from TclpGetAllocCache");
    }
    return result;
}

void
TclpSetAllocCache(
    void *ptr)
{
    BOOL success;
    success = TlsSetValue(tlsKey, ptr);
    if (!success) {
	Tcl_Panic("TlsSetValue failed from TclpSetAllocCache");
    }
}

void
TclpFreeAllocCache(
    void *ptr)
{
    BOOL success;

    if (ptr != NULL) {
	/*
	 * Called by us in TclpFinalizeThreadData when a thread exits and
	 * destroys the tsd key which stores allocator caches.
	 */

	TclFreeAllocCache(ptr);
	success = TlsSetValue(tlsKey, NULL);
	if (!success) {
	    Tcl_Panic("TlsSetValue failed from TclpFreeAllocCache");
	}
    } else if (once) {
	/*
	 * Called by us in TclFinalizeThreadAlloc() during the library
	 * finalization initiated from Tcl_Finalize()
	 */

	success = TlsFree(tlsKey);
	if (!success) {
	    Tcl_Panic("TlsFree failed from TclpFreeAllocCache");
	}
	once = 0; /* reset for next time. */
    }

}
#endif /* USE_THREAD_ALLOC */


void *TclpThreadCreateKey (void) {
    DWORD *key;

    key = TclpSysAlloc(sizeof *key, 0);
    if (key == NULL) {
	Tcl_Panic("unable to allocate thread key!");
    }
    
    *key = TlsAlloc();
    
    return key;
}

void TclpThreadDeleteKey(void *keyPtr) {
    DWORD *key = keyPtr;

    if (!TlsFree(*key)) {
	Tcl_Panic("unable to delete key");
    }

    TclpSysFree(keyPtr);
}

void TclpThreadSetMasterTSD(void *tsdKeyPtr, void *ptr) {
    DWORD *key = tsdKeyPtr;
    
    if (!TlsSetValue(*key, ptr)) {
	Tcl_Panic("unable to set master TSD value");
    }
}

void *TclpThreadGetMasterTSD(void *tsdKeyPtr) {
    DWORD *key = tsdKeyPtr;

    return TlsGetValue(*key);
}

#endif /* TCL_THREADS */

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */