threads.c@ 59049

最後變更在這個檔案從59049是 58072,由 vboxsync 提交於 9 年前
libxml 2.9.2 unmodified
屬性 svn:eol-style 設為 `native`
檔案大小: 26.5 KB

行
1	/**
2	* threads.c: set of generic threading related routines
3	*
4	* See Copyright for the status of this software.
5	*
6	* Gary Pennington <[email protected]>
7	* [email protected]
8	*/
9
10	#define IN_LIBXML
11	#include "libxml.h"
12
13	#include <string.h>
14
15	#include <libxml/threads.h>
16	#include <libxml/globals.h>
17
18	#ifdef HAVE_SYS_TYPES_H
19	#include <sys/types.h>
20	#endif
21	#ifdef HAVE_UNISTD_H
22	#include <unistd.h>
23	#endif
24	#ifdef HAVE_STDLIB_H
25	#include <stdlib.h>
26	#endif
27	#ifdef HAVE_PTHREAD_H
28	#include <pthread.h>
29	#elif defined HAVE_WIN32_THREADS
30	#include <windows.h>
31	#ifndef HAVE_COMPILER_TLS
32	#include <process.h>
33	#endif
34	#endif
35
36	#ifdef HAVE_BEOS_THREADS
37	#include <OS.h>
38	#include <TLS.h>
39	#endif
40
41	#if defined(SOLARIS)
42	#include <note.h>
43	#endif
44
45	/* #define DEBUG_THREADS */
46
47	#ifdef HAVE_PTHREAD_H
48
49	static int libxml_is_threaded = -1;
50	#ifdef __GNUC__
51	#ifdef linux
52	#if (__GNUC__ == 3 && __GNUC_MINOR__ >= 3) \|\| (__GNUC__ > 3)
53	extern int pthread_once (pthread_once_t *__once_control,
54	void (*__init_routine) (void))
55	__attribute((weak));
56	extern void *pthread_getspecific (pthread_key_t __key)
57	__attribute((weak));
58	extern int pthread_setspecific (pthread_key_t __key,
59	__const void *__pointer)
60	__attribute((weak));
61	extern int pthread_key_create (pthread_key_t *__key,
62	void (__destr_function) (void ))
63	__attribute((weak));
64	extern int pthread_key_delete (pthread_key_t __key)
65	__attribute((weak));
66	extern int pthread_mutex_init ()
67	__attribute((weak));
68	extern int pthread_mutex_destroy ()
69	__attribute((weak));
70	extern int pthread_mutex_lock ()
71	__attribute((weak));
72	extern int pthread_mutex_unlock ()
73	__attribute((weak));
74	extern int pthread_cond_init ()
75	__attribute((weak));
76	extern int pthread_cond_destroy ()
77	__attribute((weak));
78	extern int pthread_cond_wait ()
79	__attribute((weak));
80	extern int pthread_equal ()
81	__attribute((weak));
82	extern pthread_t pthread_self ()
83	__attribute((weak));
84	extern int pthread_key_create ()
85	__attribute((weak));
86	extern int pthread_key_delete ()
87	__attribute((weak));
88	extern int pthread_cond_signal ()
89	__attribute((weak));
90	#endif
91	#endif /* linux */
92	#endif /* __GNUC__ */
93	#endif /* HAVE_PTHREAD_H */
94
95	/*
96	* TODO: this module still uses malloc/free and not xmlMalloc/xmlFree
97	* to avoid some crazyness since xmlMalloc/xmlFree may actually
98	* be hosted on allocated blocks needing them for the allocation ...
99	*/
100
101	/*
102	* xmlMutex are a simple mutual exception locks
103	*/
104	struct _xmlMutex {
105	#ifdef HAVE_PTHREAD_H
106	pthread_mutex_t lock;
107	#elif defined HAVE_WIN32_THREADS
108	HANDLE mutex;
109	#elif defined HAVE_BEOS_THREADS
110	sem_id sem;
111	thread_id tid;
112	#else
113	int empty;
114	#endif
115	};
116
117	/*
118	* xmlRMutex are reentrant mutual exception locks
119	*/
120	struct _xmlRMutex {
121	#ifdef HAVE_PTHREAD_H
122	pthread_mutex_t lock;
123	unsigned int held;
124	unsigned int waiters;
125	pthread_t tid;
126	pthread_cond_t cv;
127	#elif defined HAVE_WIN32_THREADS
128	CRITICAL_SECTION cs;
129	unsigned int count;
130	#elif defined HAVE_BEOS_THREADS
131	xmlMutexPtr lock;
132	thread_id tid;
133	int32 count;
134	#else
135	int empty;
136	#endif
137	};
138
139	/*
140	* This module still has some internal static data.
141	* - xmlLibraryLock a global lock
142	* - globalkey used for per-thread data
143	*/
144
145	#ifdef HAVE_PTHREAD_H
146	static pthread_key_t globalkey;
147	static pthread_t mainthread;
148	static pthread_once_t once_control = PTHREAD_ONCE_INIT;
149	static pthread_once_t once_control_init = PTHREAD_ONCE_INIT;
150	static pthread_mutex_t global_init_lock = PTHREAD_MUTEX_INITIALIZER;
151	#elif defined HAVE_WIN32_THREADS
152	#if defined(HAVE_COMPILER_TLS)
153	static __declspec(thread) xmlGlobalState tlstate;
154	static __declspec(thread) int tlstate_inited = 0;
155	#else /* HAVE_COMPILER_TLS */
156	static DWORD globalkey = TLS_OUT_OF_INDEXES;
157	#endif /* HAVE_COMPILER_TLS */
158	static DWORD mainthread;
159	static struct {
160	DWORD done;
161	DWORD control;
162	} run_once = { 0, 0};
163	static volatile LPCRITICAL_SECTION global_init_lock = NULL;
164
165	/* endif HAVE_WIN32_THREADS */
166	#elif defined HAVE_BEOS_THREADS
167	int32 globalkey = 0;
168	thread_id mainthread = 0;
169	int32 run_once_init = 0;
170	static int32 global_init_lock = -1;
171	static vint32 global_init_count = 0;
172	#endif
173
174	static xmlRMutexPtr xmlLibraryLock = NULL;
175
176	#ifdef LIBXML_THREAD_ENABLED
177	static void xmlOnceInit(void);
178	#endif
179
180	/**
181	* xmlNewMutex:
182	*
183	* xmlNewMutex() is used to allocate a libxml2 token struct for use in
184	* synchronizing access to data.
185	*
186	* Returns a new simple mutex pointer or NULL in case of error
187	*/
188	xmlMutexPtr
189	xmlNewMutex(void)
190	{
191	xmlMutexPtr tok;
192
193	if ((tok = malloc(sizeof(xmlMutex))) == NULL)
194	return (NULL);
195	#ifdef HAVE_PTHREAD_H
196	if (libxml_is_threaded != 0)
197	pthread_mutex_init(&tok->lock, NULL);
198	#elif defined HAVE_WIN32_THREADS
199	tok->mutex = CreateMutex(NULL, FALSE, NULL);
200	#elif defined HAVE_BEOS_THREADS
201	if ((tok->sem = create_sem(1, "xmlMutex")) < B_OK) {
202	free(tok);
203	return NULL;
204	}
205	tok->tid = -1;
206	#endif
207	return (tok);
208	}
209
210	/**
211	* xmlFreeMutex:
212	* @tok: the simple mutex
213	*
214	* xmlFreeMutex() is used to reclaim resources associated with a libxml2 token
215	* struct.
216	*/
217	void
218	xmlFreeMutex(xmlMutexPtr tok)
219	{
220	if (tok == NULL)
221	return;
222
223	#ifdef HAVE_PTHREAD_H
224	if (libxml_is_threaded != 0)
225	pthread_mutex_destroy(&tok->lock);
226	#elif defined HAVE_WIN32_THREADS
227	CloseHandle(tok->mutex);
228	#elif defined HAVE_BEOS_THREADS
229	delete_sem(tok->sem);
230	#endif
231	free(tok);
232	}
233
234	/**
235	* xmlMutexLock:
236	* @tok: the simple mutex
237	*
238	* xmlMutexLock() is used to lock a libxml2 token.
239	*/
240	void
241	xmlMutexLock(xmlMutexPtr tok)
242	{
243	if (tok == NULL)
244	return;
245	#ifdef HAVE_PTHREAD_H
246	if (libxml_is_threaded != 0)
247	pthread_mutex_lock(&tok->lock);
248	#elif defined HAVE_WIN32_THREADS
249	WaitForSingleObject(tok->mutex, INFINITE);
250	#elif defined HAVE_BEOS_THREADS
251	if (acquire_sem(tok->sem) != B_NO_ERROR) {
252	#ifdef DEBUG_THREADS
253	xmlGenericError(xmlGenericErrorContext,
254	"xmlMutexLock():BeOS:Couldn't aquire semaphore\n");
255	#endif
256	}
257	tok->tid = find_thread(NULL);
258	#endif
259
260	}
261
262	/**
263	* xmlMutexUnlock:
264	* @tok: the simple mutex
265	*
266	* xmlMutexUnlock() is used to unlock a libxml2 token.
267	*/
268	void
269	xmlMutexUnlock(xmlMutexPtr tok)
270	{
271	if (tok == NULL)
272	return;
273	#ifdef HAVE_PTHREAD_H
274	if (libxml_is_threaded != 0)
275	pthread_mutex_unlock(&tok->lock);
276	#elif defined HAVE_WIN32_THREADS
277	ReleaseMutex(tok->mutex);
278	#elif defined HAVE_BEOS_THREADS
279	if (tok->tid == find_thread(NULL)) {
280	tok->tid = -1;
281	release_sem(tok->sem);
282	}
283	#endif
284	}
285
286	/**
287	* xmlNewRMutex:
288	*
289	* xmlRNewMutex() is used to allocate a reentrant mutex for use in
290	* synchronizing access to data. token_r is a re-entrant lock and thus useful
291	* for synchronizing access to data structures that may be manipulated in a
292	* recursive fashion.
293	*
294	* Returns the new reentrant mutex pointer or NULL in case of error
295	*/
296	xmlRMutexPtr
297	xmlNewRMutex(void)
298	{
299	xmlRMutexPtr tok;
300
301	if ((tok = malloc(sizeof(xmlRMutex))) == NULL)
302	return (NULL);
303	#ifdef HAVE_PTHREAD_H
304	if (libxml_is_threaded != 0) {
305	pthread_mutex_init(&tok->lock, NULL);
306	tok->held = 0;
307	tok->waiters = 0;
308	pthread_cond_init(&tok->cv, NULL);
309	}
310	#elif defined HAVE_WIN32_THREADS
311	InitializeCriticalSection(&tok->cs);
312	tok->count = 0;
313	#elif defined HAVE_BEOS_THREADS
314	if ((tok->lock = xmlNewMutex()) == NULL) {
315	free(tok);
316	return NULL;
317	}
318	tok->count = 0;
319	#endif
320	return (tok);
321	}
322
323	/**
324	* xmlFreeRMutex:
325	* @tok: the reentrant mutex
326	*
327	* xmlRFreeMutex() is used to reclaim resources associated with a
328	* reentrant mutex.
329	*/
330	void
331	xmlFreeRMutex(xmlRMutexPtr tok ATTRIBUTE_UNUSED)
332	{
333	if (tok == NULL)
334	return;
335	#ifdef HAVE_PTHREAD_H
336	if (libxml_is_threaded != 0) {
337	pthread_mutex_destroy(&tok->lock);
338	pthread_cond_destroy(&tok->cv);
339	}
340	#elif defined HAVE_WIN32_THREADS
341	DeleteCriticalSection(&tok->cs);
342	#elif defined HAVE_BEOS_THREADS
343	xmlFreeMutex(tok->lock);
344	#endif
345	free(tok);
346	}
347
348	/**
349	* xmlRMutexLock:
350	* @tok: the reentrant mutex
351	*
352	* xmlRMutexLock() is used to lock a libxml2 token_r.
353	*/
354	void
355	xmlRMutexLock(xmlRMutexPtr tok)
356	{
357	if (tok == NULL)
358	return;
359	#ifdef HAVE_PTHREAD_H
360	if (libxml_is_threaded == 0)
361	return;
362
363	pthread_mutex_lock(&tok->lock);
364	if (tok->held) {
365	if (pthread_equal(tok->tid, pthread_self())) {
366	tok->held++;
367	pthread_mutex_unlock(&tok->lock);
368	return;
369	} else {
370	tok->waiters++;
371	while (tok->held)
372	pthread_cond_wait(&tok->cv, &tok->lock);
373	tok->waiters--;
374	}
375	}
376	tok->tid = pthread_self();
377	tok->held = 1;
378	pthread_mutex_unlock(&tok->lock);
379	#elif defined HAVE_WIN32_THREADS
380	EnterCriticalSection(&tok->cs);
381	tok->count++;
382	#elif defined HAVE_BEOS_THREADS
383	if (tok->lock->tid == find_thread(NULL)) {
384	tok->count++;
385	return;
386	} else {
387	xmlMutexLock(tok->lock);
388	tok->count = 1;
389	}
390	#endif
391	}
392
393	/**
394	* xmlRMutexUnlock:
395	* @tok: the reentrant mutex
396	*
397	* xmlRMutexUnlock() is used to unlock a libxml2 token_r.
398	*/
399	void
400	xmlRMutexUnlock(xmlRMutexPtr tok ATTRIBUTE_UNUSED)
401	{
402	if (tok == NULL)
403	return;
404	#ifdef HAVE_PTHREAD_H
405	if (libxml_is_threaded == 0)
406	return;
407
408	pthread_mutex_lock(&tok->lock);
409	tok->held--;
410	if (tok->held == 0) {
411	if (tok->waiters)
412	pthread_cond_signal(&tok->cv);
413	memset(&tok->tid, 0, sizeof(tok->tid));
414	}
415	pthread_mutex_unlock(&tok->lock);
416	#elif defined HAVE_WIN32_THREADS
417	if (tok->count > 0) {
418	LeaveCriticalSection(&tok->cs);
419	tok->count--;
420	}
421	#elif defined HAVE_BEOS_THREADS
422	if (tok->lock->tid == find_thread(NULL)) {
423	tok->count--;
424	if (tok->count == 0) {
425	xmlMutexUnlock(tok->lock);
426	}
427	return;
428	}
429	#endif
430	}
431
432	/**
433	* xmlGlobalInitMutexLock
434	*
435	* Makes sure that the global initialization mutex is initialized and
436	* locks it.
437	*/
438	void
439	__xmlGlobalInitMutexLock(void)
440	{
441	/* Make sure the global init lock is initialized and then lock it. */
442	#ifdef HAVE_PTHREAD_H
443	/* The mutex is statically initialized, so we just lock it. */
444	if (pthread_mutex_lock != NULL)
445	pthread_mutex_lock(&global_init_lock);
446	#elif defined HAVE_WIN32_THREADS
447	LPCRITICAL_SECTION cs;
448
449	/* Create a new critical section */
450	if (global_init_lock == NULL) {
451	cs = malloc(sizeof(CRITICAL_SECTION));
452	if (cs == NULL) {
453	xmlGenericError(xmlGenericErrorContext,
454	"xmlGlobalInitMutexLock: out of memory\n");
455	return;
456	}
457	InitializeCriticalSection(cs);
458
459	/* Swap it into the global_init_lock */
460	#ifdef InterlockedCompareExchangePointer
461	InterlockedCompareExchangePointer(&global_init_lock, cs, NULL);
462	#else /* Use older void* version */
463	InterlockedCompareExchange((void **) &global_init_lock,
464	(void *) cs, NULL);
465	#endif /* InterlockedCompareExchangePointer */
466
467	/* If another thread successfully recorded its critical
468	* section in the global_init_lock then discard the one
469	* allocated by this thread. */
470	if (global_init_lock != cs) {
471	DeleteCriticalSection(cs);
472	free(cs);
473	}
474	}
475
476	/* Lock the chosen critical section */
477	EnterCriticalSection(global_init_lock);
478	#elif defined HAVE_BEOS_THREADS
479	int32 sem;
480
481	/* Allocate a new semaphore */
482	sem = create_sem(1, "xmlGlobalinitMutex");
483
484	while (global_init_lock == -1) {
485	if (atomic_add(&global_init_count, 1) == 0) {
486	global_init_lock = sem;
487	} else {
488	snooze(1);
489	atomic_add(&global_init_count, -1);
490	}
491	}
492
493	/* If another thread successfully recorded its critical
494	* section in the global_init_lock then discard the one
495	* allocated by this thread. */
496	if (global_init_lock != sem)
497	delete_sem(sem);
498
499	/* Acquire the chosen semaphore */
500	if (acquire_sem(global_init_lock) != B_NO_ERROR) {
501	#ifdef DEBUG_THREADS
502	xmlGenericError(xmlGenericErrorContext,
503	"xmlGlobalInitMutexLock():BeOS:Couldn't acquire semaphore\n");
504	#endif
505	}
506	#endif
507	}
508
509	void
510	__xmlGlobalInitMutexUnlock(void)
511	{
512	#ifdef HAVE_PTHREAD_H
513	if (pthread_mutex_unlock != NULL)
514	pthread_mutex_unlock(&global_init_lock);
515	#elif defined HAVE_WIN32_THREADS
516	if (global_init_lock != NULL) {
517	LeaveCriticalSection(global_init_lock);
518	}
519	#elif defined HAVE_BEOS_THREADS
520	release_sem(global_init_lock);
521	#endif
522	}
523
524	/**
525	* xmlGlobalInitMutexDestroy
526	*
527	* Makes sure that the global initialization mutex is destroyed before
528	* application termination.
529	*/
530	void
531	__xmlGlobalInitMutexDestroy(void)
532	{
533	#ifdef HAVE_PTHREAD_H
534	#elif defined HAVE_WIN32_THREADS
535	if (global_init_lock != NULL) {
536	DeleteCriticalSection(global_init_lock);
537	free(global_init_lock);
538	global_init_lock = NULL;
539	}
540	#endif
541	}
542
543	/************************************************************************
544	* *
545	* Per thread global state handling *
546	* *
547	************************************************************************/
548
549	#ifdef LIBXML_THREAD_ENABLED
550	#ifdef xmlLastError
551	#undef xmlLastError
552	#endif
553
554	/**
555	* xmlFreeGlobalState:
556	* @state: a thread global state
557	*
558	* xmlFreeGlobalState() is called when a thread terminates with a non-NULL
559	* global state. It is is used here to reclaim memory resources.
560	*/
561	static void
562	xmlFreeGlobalState(void *state)
563	{
564	xmlGlobalState gs = (xmlGlobalState ) state;
565
566	/* free any memory allocated in the thread's xmlLastError */
567	xmlResetError(&(gs->xmlLastError));
568	free(state);
569	}
570
571	/**
572	* xmlNewGlobalState:
573	*
574	* xmlNewGlobalState() allocates a global state. This structure is used to
575	* hold all data for use by a thread when supporting backwards compatibility
576	* of libxml2 to pre-thread-safe behaviour.
577	*
578	* Returns the newly allocated xmlGlobalStatePtr or NULL in case of error
579	*/
580	static xmlGlobalStatePtr
581	xmlNewGlobalState(void)
582	{
583	xmlGlobalState *gs;
584
585	gs = malloc(sizeof(xmlGlobalState));
586	if (gs == NULL) {
587	xmlGenericError(xmlGenericErrorContext,
588	"xmlGetGlobalState: out of memory\n");
589	return (NULL);
590	}
591
592	memset(gs, 0, sizeof(xmlGlobalState));
593	xmlInitializeGlobalState(gs);
594	return (gs);
595	}
596	#endif /* LIBXML_THREAD_ENABLED */
597
598	#ifdef HAVE_PTHREAD_H
599	#elif defined HAVE_WIN32_THREADS
600	#if !defined(HAVE_COMPILER_TLS)
601	#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
602	typedef struct _xmlGlobalStateCleanupHelperParams {
603	HANDLE thread;
604	void *memory;
605	} xmlGlobalStateCleanupHelperParams;
606
607	static void XMLCDECL
608	xmlGlobalStateCleanupHelper(void *p)
609	{
610	xmlGlobalStateCleanupHelperParams *params =
611	(xmlGlobalStateCleanupHelperParams *) p;
612	WaitForSingleObject(params->thread, INFINITE);
613	CloseHandle(params->thread);
614	xmlFreeGlobalState(params->memory);
615	free(params);
616	_endthread();
617	}
618	#else /* LIBXML_STATIC && !LIBXML_STATIC_FOR_DLL */
619
620	typedef struct _xmlGlobalStateCleanupHelperParams {
621	void *memory;
622	struct _xmlGlobalStateCleanupHelperParams *prev;
623	struct _xmlGlobalStateCleanupHelperParams *next;
624	} xmlGlobalStateCleanupHelperParams;
625
626	static xmlGlobalStateCleanupHelperParams *cleanup_helpers_head = NULL;
627	static CRITICAL_SECTION cleanup_helpers_cs;
628
629	#endif /* LIBXMLSTATIC && !LIBXML_STATIC_FOR_DLL */
630	#endif /* HAVE_COMPILER_TLS */
631	#endif /* HAVE_WIN32_THREADS */
632
633	#if defined HAVE_BEOS_THREADS
634
635	/**
636	* xmlGlobalStateCleanup:
637	* @data: unused parameter
638	*
639	* Used for Beos only
640	*/
641	void
642	xmlGlobalStateCleanup(void *data)
643	{
644	void *globalval = tls_get(globalkey);
645
646	if (globalval != NULL)
647	xmlFreeGlobalState(globalval);
648	}
649	#endif
650
651	/**
652	* xmlGetGlobalState:
653	*
654	* xmlGetGlobalState() is called to retrieve the global state for a thread.
655	*
656	* Returns the thread global state or NULL in case of error
657	*/
658	xmlGlobalStatePtr
659	xmlGetGlobalState(void)
660	{
661	#ifdef HAVE_PTHREAD_H
662	xmlGlobalState *globalval;
663
664	if (libxml_is_threaded == 0)
665	return (NULL);
666
667	pthread_once(&once_control, xmlOnceInit);
668
669	if ((globalval = (xmlGlobalState *)
670	pthread_getspecific(globalkey)) == NULL) {
671	xmlGlobalState *tsd = xmlNewGlobalState();
672	if (tsd == NULL)
673	return(NULL);
674
675	pthread_setspecific(globalkey, tsd);
676	return (tsd);
677	}
678	return (globalval);
679	#elif defined HAVE_WIN32_THREADS
680	#if defined(HAVE_COMPILER_TLS)
681	if (!tlstate_inited) {
682	tlstate_inited = 1;
683	xmlInitializeGlobalState(&tlstate);
684	}
685	return &tlstate;
686	#else /* HAVE_COMPILER_TLS */
687	xmlGlobalState *globalval;
688	xmlGlobalStateCleanupHelperParams *p;
689
690	xmlOnceInit();
691	#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
692	globalval = (xmlGlobalState *) TlsGetValue(globalkey);
693	#else
694	p = (xmlGlobalStateCleanupHelperParams *) TlsGetValue(globalkey);
695	globalval = (xmlGlobalState *) (p ? p->memory : NULL);
696	#endif
697	if (globalval == NULL) {
698	xmlGlobalState *tsd = xmlNewGlobalState();
699
700	if (tsd == NULL)
701	return(NULL);
702	p = (xmlGlobalStateCleanupHelperParams *)
703	malloc(sizeof(xmlGlobalStateCleanupHelperParams));
704	if (p == NULL) {
705	xmlGenericError(xmlGenericErrorContext,
706	"xmlGetGlobalState: out of memory\n");
707	xmlFreeGlobalState(tsd);
708	return(NULL);
709	}
710	p->memory = tsd;
711	#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
712	DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
713	GetCurrentProcess(), &p->thread, 0, TRUE,
714	DUPLICATE_SAME_ACCESS);
715	TlsSetValue(globalkey, tsd);
716	_beginthread(xmlGlobalStateCleanupHelper, 0, p);
717	#else
718	EnterCriticalSection(&cleanup_helpers_cs);
719	if (cleanup_helpers_head != NULL) {
720	cleanup_helpers_head->prev = p;
721	}
722	p->next = cleanup_helpers_head;
723	p->prev = NULL;
724	cleanup_helpers_head = p;
725	TlsSetValue(globalkey, p);
726	LeaveCriticalSection(&cleanup_helpers_cs);
727	#endif
728
729	return (tsd);
730	}
731	return (globalval);
732	#endif /* HAVE_COMPILER_TLS */
733	#elif defined HAVE_BEOS_THREADS
734	xmlGlobalState *globalval;
735
736	xmlOnceInit();
737
738	if ((globalval = (xmlGlobalState *) tls_get(globalkey)) == NULL) {
739	xmlGlobalState *tsd = xmlNewGlobalState();
740	if (tsd == NULL)
741	return (NULL);
742
743	tls_set(globalkey, tsd);
744	on_exit_thread(xmlGlobalStateCleanup, NULL);
745	return (tsd);
746	}
747	return (globalval);
748	#else
749	return (NULL);
750	#endif
751	}
752
753	/************************************************************************
754	* *
755	* Library wide thread interfaces *
756	* *
757	************************************************************************/
758
759	/**
760	* xmlGetThreadId:
761	*
762	* xmlGetThreadId() find the current thread ID number
763	* Note that this is likely to be broken on some platforms using pthreads
764	* as the specification doesn't mandate pthread_t to be an integer type
765	*
766	* Returns the current thread ID number
767	*/
768	int
769	xmlGetThreadId(void)
770	{
771	#ifdef HAVE_PTHREAD_H
772	pthread_t id;
773	int ret;
774
775	if (libxml_is_threaded == 0)
776	return (0);
777	id = pthread_self();
778	/* horrible but preserves compat, see warning above */
779	memcpy(&ret, &id, sizeof(ret));
780	return (ret);
781	#elif defined HAVE_WIN32_THREADS
782	return GetCurrentThreadId();
783	#elif defined HAVE_BEOS_THREADS
784	return find_thread(NULL);
785	#else
786	return ((int) 0);
787	#endif
788	}
789
790	/**
791	* xmlIsMainThread:
792	*
793	* xmlIsMainThread() check whether the current thread is the main thread.
794	*
795	* Returns 1 if the current thread is the main thread, 0 otherwise
796	*/
797	int
798	xmlIsMainThread(void)
799	{
800	#ifdef HAVE_PTHREAD_H
801	if (libxml_is_threaded == -1)
802	xmlInitThreads();
803	if (libxml_is_threaded == 0)
804	return (1);
805	pthread_once(&once_control, xmlOnceInit);
806	#elif defined HAVE_WIN32_THREADS
807	xmlOnceInit();
808	#elif defined HAVE_BEOS_THREADS
809	xmlOnceInit();
810	#endif
811
812	#ifdef DEBUG_THREADS
813	xmlGenericError(xmlGenericErrorContext, "xmlIsMainThread()\n");
814	#endif
815	#ifdef HAVE_PTHREAD_H
816	return (pthread_equal(mainthread,pthread_self()));
817	#elif defined HAVE_WIN32_THREADS
818	return (mainthread == GetCurrentThreadId());
819	#elif defined HAVE_BEOS_THREADS
820	return (mainthread == find_thread(NULL));
821	#else
822	return (1);
823	#endif
824	}
825
826	/**
827	* xmlLockLibrary:
828	*
829	* xmlLockLibrary() is used to take out a re-entrant lock on the libxml2
830	* library.
831	*/
832	void
833	xmlLockLibrary(void)
834	{
835	#ifdef DEBUG_THREADS
836	xmlGenericError(xmlGenericErrorContext, "xmlLockLibrary()\n");
837	#endif
838	xmlRMutexLock(xmlLibraryLock);
839	}
840
841	/**
842	* xmlUnlockLibrary:
843	*
844	* xmlUnlockLibrary() is used to release a re-entrant lock on the libxml2
845	* library.
846	*/
847	void
848	xmlUnlockLibrary(void)
849	{
850	#ifdef DEBUG_THREADS
851	xmlGenericError(xmlGenericErrorContext, "xmlUnlockLibrary()\n");
852	#endif
853	xmlRMutexUnlock(xmlLibraryLock);
854	}
855
856	/**
857	* xmlInitThreads:
858	*
859	* xmlInitThreads() is used to to initialize all the thread related
860	* data of the libxml2 library.
861	*/
862	void
863	xmlInitThreads(void)
864	{
865	#ifdef HAVE_PTHREAD_H
866	if (libxml_is_threaded == -1) {
867	if ((pthread_once != NULL) &&
868	(pthread_getspecific != NULL) &&
869	(pthread_setspecific != NULL) &&
870	(pthread_key_create != NULL) &&
871	(pthread_key_delete != NULL) &&
872	(pthread_mutex_init != NULL) &&
873	(pthread_mutex_destroy != NULL) &&
874	(pthread_mutex_lock != NULL) &&
875	(pthread_mutex_unlock != NULL) &&
876	(pthread_cond_init != NULL) &&
877	(pthread_cond_destroy != NULL) &&
878	(pthread_cond_wait != NULL) &&
879	(pthread_equal != NULL) &&
880	(pthread_self != NULL) &&
881	(pthread_cond_signal != NULL)) {
882	libxml_is_threaded = 1;
883
884	/* fprintf(stderr, "Running multithreaded\n"); */
885	} else {
886
887	/* fprintf(stderr, "Running without multithread\n"); */
888	libxml_is_threaded = 0;
889	}
890	}
891	#elif defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) \|\| defined(LIBXML_STATIC_FOR_DLL))
892	InitializeCriticalSection(&cleanup_helpers_cs);
893	#endif
894	}
895
896	/**
897	* xmlCleanupThreads:
898	*
899	* xmlCleanupThreads() is used to to cleanup all the thread related
900	* data of the libxml2 library once processing has ended.
901	*
902	* WARNING: if your application is multithreaded or has plugin support
903	* calling this may crash the application if another thread or
904	* a plugin is still using libxml2. It's sometimes very hard to
905	* guess if libxml2 is in use in the application, some libraries
906	* or plugins may use it without notice. In case of doubt abstain
907	* from calling this function or do it just before calling exit()
908	* to avoid leak reports from valgrind !
909	*/
910	void
911	xmlCleanupThreads(void)
912	{
913	#ifdef DEBUG_THREADS
914	xmlGenericError(xmlGenericErrorContext, "xmlCleanupThreads()\n");
915	#endif
916	#ifdef HAVE_PTHREAD_H
917	if ((libxml_is_threaded) && (pthread_key_delete != NULL))
918	pthread_key_delete(globalkey);
919	once_control = once_control_init;
920	#elif defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) \|\| defined(LIBXML_STATIC_FOR_DLL))
921	if (globalkey != TLS_OUT_OF_INDEXES) {
922	xmlGlobalStateCleanupHelperParams *p;
923
924	EnterCriticalSection(&cleanup_helpers_cs);
925	p = cleanup_helpers_head;
926	while (p != NULL) {
927	xmlGlobalStateCleanupHelperParams *temp = p;
928
929	p = p->next;
930	xmlFreeGlobalState(temp->memory);
931	free(temp);
932	}
933	cleanup_helpers_head = 0;
934	LeaveCriticalSection(&cleanup_helpers_cs);
935	TlsFree(globalkey);
936	globalkey = TLS_OUT_OF_INDEXES;
937	}
938	DeleteCriticalSection(&cleanup_helpers_cs);
939	#endif
940	}
941
942	#ifdef LIBXML_THREAD_ENABLED
943
944	/**
945	* xmlOnceInit
946	*
947	* xmlOnceInit() is used to initialize the value of mainthread for use
948	* in other routines. This function should only be called using
949	* pthread_once() in association with the once_control variable to ensure
950	* that the function is only called once. See man pthread_once for more
951	* details.
952	*/
953	static void
954	xmlOnceInit(void)
955	{
956	#ifdef HAVE_PTHREAD_H
957	(void) pthread_key_create(&globalkey, xmlFreeGlobalState);
958	mainthread = pthread_self();
959	__xmlInitializeDict();
960	#elif defined(HAVE_WIN32_THREADS)
961	if (!run_once.done) {
962	if (InterlockedIncrement(&run_once.control) == 1) {
963	#if !defined(HAVE_COMPILER_TLS)
964	globalkey = TlsAlloc();
965	#endif
966	mainthread = GetCurrentThreadId();
967	__xmlInitializeDict();
968	run_once.done = 1;
969	} else {
970	/* Another thread is working; give up our slice and
971	* wait until they're done. */
972	while (!run_once.done)
973	Sleep(0);
974	}
975	}
976	#elif defined HAVE_BEOS_THREADS
977	if (atomic_add(&run_once_init, 1) == 0) {
978	globalkey = tls_allocate();
979	tls_set(globalkey, NULL);
980	mainthread = find_thread(NULL);
981	__xmlInitializeDict();
982	} else
983	atomic_add(&run_once_init, -1);
984	#endif
985	}
986	#endif
987
988	/**
989	* DllMain:
990	* @hinstDLL: handle to DLL instance
991	* @fdwReason: Reason code for entry
992	* @lpvReserved: generic pointer (depends upon reason code)
993	*
994	* Entry point for Windows library. It is being used to free thread-specific
995	* storage.
996	*
997	* Returns TRUE always
998	*/
999	#ifdef HAVE_PTHREAD_H
1000	#elif defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) \|\| defined(LIBXML_STATIC_FOR_DLL))
1001	#if defined(LIBXML_STATIC_FOR_DLL)
1002	BOOL XMLCALL
1003	xmlDllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
1004	#else
1005	BOOL WINAPI
1006	DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
1007	#endif
1008	{
1009	switch (fdwReason) {
1010	case DLL_THREAD_DETACH:
1011	if (globalkey != TLS_OUT_OF_INDEXES) {
1012	xmlGlobalState *globalval = NULL;
1013	xmlGlobalStateCleanupHelperParams *p =
1014	(xmlGlobalStateCleanupHelperParams *)
1015	TlsGetValue(globalkey);
1016	globalval = (xmlGlobalState *) (p ? p->memory : NULL);
1017	if (globalval) {
1018	xmlFreeGlobalState(globalval);
1019	TlsSetValue(globalkey, NULL);
1020	}
1021	if (p) {
1022	EnterCriticalSection(&cleanup_helpers_cs);
1023	if (p == cleanup_helpers_head)
1024	cleanup_helpers_head = p->next;
1025	else
1026	p->prev->next = p->next;
1027	if (p->next != NULL)
1028	p->next->prev = p->prev;
1029	LeaveCriticalSection(&cleanup_helpers_cs);
1030	free(p);
1031	}
1032	}
1033	break;
1034	}
1035	return TRUE;
1036	}
1037	#endif
1038	#define bottom_threads
1039	#include "elfgcchack.h"

注意: 瀏覽 TracBrowser 來幫助您使用儲存庫瀏覽器

source: vbox/trunk/src/libs/libxml2-2.9.2/threads.c@ 59049

以其他格式下載: