threads.c.svn-base

这是一个用于解析xml文件的类库。使用这个类库

 *
 * Returns the newly allocated xmlGlobalStatePtr or NULL in case of error
 */
static xmlGlobalStatePtr
xmlNewGlobalState(void)
{
    xmlGlobalState *gs;
    
    gs = malloc(sizeof(xmlGlobalState));
    if (gs == NULL)
	return(NULL);

    memset(gs, 0, sizeof(xmlGlobalState));
    xmlInitializeGlobalState(gs);
    return (gs);
}
#endif /* LIBXML_THREAD_ENABLED */


#ifdef HAVE_WIN32_THREADS
#if !defined(HAVE_COMPILER_TLS)
#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
typedef struct _xmlGlobalStateCleanupHelperParams
{
    HANDLE thread;
    void *memory;
} xmlGlobalStateCleanupHelperParams;

static void xmlGlobalStateCleanupHelper (void *p)
{
    xmlGlobalStateCleanupHelperParams *params = (xmlGlobalStateCleanupHelperParams *) p;
    WaitForSingleObject(params->thread, INFINITE);
    CloseHandle(params->thread);
    xmlFreeGlobalState(params->memory);
    free(params);
    _endthread();
}
#else /* LIBXML_STATIC && !LIBXML_STATIC_FOR_DLL */

typedef struct _xmlGlobalStateCleanupHelperParams
{
    void *memory;
    struct _xmlGlobalStateCleanupHelperParams * prev;
    struct _xmlGlobalStateCleanupHelperParams * next;
} xmlGlobalStateCleanupHelperParams;

static xmlGlobalStateCleanupHelperParams * cleanup_helpers_head = NULL;
static CRITICAL_SECTION cleanup_helpers_cs;

#endif /* LIBXMLSTATIC && !LIBXML_STATIC_FOR_DLL */
#endif /* HAVE_COMPILER_TLS */
#endif /* HAVE_WIN32_THREADS */

#if defined HAVE_BEOS_THREADS
/**
 * xmlGlobalStateCleanup:
 * @data: unused parameter
 *
 * Used for Beos only
 */
void xmlGlobalStateCleanup(void *data)
{
	void *globalval = tls_get(globalkey);
	if (globalval != NULL)
		xmlFreeGlobalState(globalval);
}
#endif

/**
 * xmlGetGlobalState:
 *
 * xmlGetGlobalState() is called to retrieve the global state for a thread.
 *
 * Returns the thread global state or NULL in case of error
 */
xmlGlobalStatePtr
xmlGetGlobalState(void)
{
#ifdef HAVE_PTHREAD_H
    xmlGlobalState *globalval;

    pthread_once(&once_control, xmlOnceInit);

    if ((globalval = (xmlGlobalState *)
		pthread_getspecific(globalkey)) == NULL) {
        xmlGlobalState *tsd = xmlNewGlobalState();

        pthread_setspecific(globalkey, tsd);
        return (tsd);
    }
    return (globalval);
#elif defined HAVE_WIN32_THREADS
#if defined(HAVE_COMPILER_TLS)
    if (!tlstate_inited) {
	tlstate_inited = 1;
	xmlInitializeGlobalState(&tlstate);
    }
    return &tlstate;
#else /* HAVE_COMPILER_TLS */
    xmlGlobalState *globalval;
    xmlGlobalStateCleanupHelperParams * p;

    if (run_once_init) { 
	run_once_init = 0; 
	xmlOnceInit(); 
    }
#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
    globalval = (xmlGlobalState *)TlsGetValue(globalkey);
#else
    p = (xmlGlobalStateCleanupHelperParams*)TlsGetValue(globalkey);
    globalval = (xmlGlobalState *)(p ? p->memory : NULL);
#endif
    if (globalval == NULL) {
	xmlGlobalState *tsd = xmlNewGlobalState();
	p = (xmlGlobalStateCleanupHelperParams *) malloc(sizeof(xmlGlobalStateCleanupHelperParams));
	p->memory = tsd;
#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
	DuplicateHandle(GetCurrentProcess(), GetCurrentThread(), 
		GetCurrentProcess(), &p->thread, 0, TRUE, DUPLICATE_SAME_ACCESS);
	TlsSetValue(globalkey, tsd);
	_beginthread(xmlGlobalStateCleanupHelper, 0, p);
#else
	EnterCriticalSection(&cleanup_helpers_cs);	
        if (cleanup_helpers_head != NULL) {
            cleanup_helpers_head->prev = p;
        }
	p->next = cleanup_helpers_head;
	p->prev = NULL;
	cleanup_helpers_head = p;
	TlsSetValue(globalkey, p);
	LeaveCriticalSection(&cleanup_helpers_cs);	
#endif

	return (tsd);
    }
    return (globalval);
#endif /* HAVE_COMPILER_TLS */
#elif defined HAVE_BEOS_THREADS
    xmlGlobalState *globalval;

    xmlOnceInit();

    if ((globalval = (xmlGlobalState *)
		tls_get(globalkey)) == NULL) {
        xmlGlobalState *tsd = xmlNewGlobalState();

        tls_set(globalkey, tsd);
        on_exit_thread(xmlGlobalStateCleanup, NULL);
        return (tsd);
    }
    return (globalval);
#else
    return(NULL);
#endif
}

/************************************************************************
 *									*
 *			Library wide thread interfaces			*
 *									*
 ************************************************************************/

/**
 * xmlGetThreadId:
 *
 * xmlGetThreadId() find the current thread ID number
 *
 * Returns the current thread ID number
 */
int
xmlGetThreadId(void)
{
#ifdef HAVE_PTHREAD_H
    return((int) pthread_self());
#elif defined HAVE_WIN32_THREADS
    return GetCurrentThreadId();
#elif defined HAVE_BEOS_THREADS
	return find_thread(NULL);
#else
    return((int) 0);
#endif
}

/**
 * xmlIsMainThread:
 *
 * xmlIsMainThread() check whether the current thread is the main thread.
 *
 * Returns 1 if the current thread is the main thread, 0 otherwise
 */
int
xmlIsMainThread(void)
{
#ifdef HAVE_PTHREAD_H
    pthread_once(&once_control, xmlOnceInit);
#elif defined HAVE_WIN32_THREADS
    if (run_once_init) { 
	run_once_init = 0; 
	xmlOnceInit (); 
    }
#elif defined HAVE_BEOS_THREADS
	xmlOnceInit();
#endif
        
#ifdef DEBUG_THREADS
    xmlGenericError(xmlGenericErrorContext, "xmlIsMainThread()\n");
#endif
#ifdef HAVE_PTHREAD_H
    return(mainthread == pthread_self());
#elif defined HAVE_WIN32_THREADS
    return(mainthread == GetCurrentThreadId ());
#elif defined HAVE_BEOS_THREADS
	return(mainthread == find_thread(NULL));
#else
    return(1);
#endif
}

/**
 * xmlLockLibrary:
 *
 * xmlLockLibrary() is used to take out a re-entrant lock on the libxml2
 * library.
 */
void
xmlLockLibrary(void)
{
#ifdef DEBUG_THREADS
    xmlGenericError(xmlGenericErrorContext, "xmlLockLibrary()\n");
#endif
    xmlRMutexLock(xmlLibraryLock);
}

/**
 * xmlUnlockLibrary:
 *
 * xmlUnlockLibrary() is used to release a re-entrant lock on the libxml2
 * library.
 */
void
xmlUnlockLibrary(void)
{
#ifdef DEBUG_THREADS
    xmlGenericError(xmlGenericErrorContext, "xmlUnlockLibrary()\n");
#endif
    xmlRMutexUnlock(xmlLibraryLock);
}

/**
 * xmlInitThreads:
 *
 * xmlInitThreads() is used to to initialize all the thread related
 * data of the libxml2 library.
 */
void
xmlInitThreads(void)
{
#ifdef DEBUG_THREADS
    xmlGenericError(xmlGenericErrorContext, "xmlInitThreads()\n");
#endif
#if defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) || defined(LIBXML_STATIC_FOR_DLL))
    InitializeCriticalSection(&cleanup_helpers_cs);
#endif
}

/**
 * xmlCleanupThreads:
 *
 * xmlCleanupThreads() is used to to cleanup all the thread related
 * data of the libxml2 library once processing has ended.
 */
void
xmlCleanupThreads(void)
{
#ifdef DEBUG_THREADS
    xmlGenericError(xmlGenericErrorContext, "xmlCleanupThreads()\n");
#endif
#if defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) || defined(LIBXML_STATIC_FOR_DLL))
    if (globalkey != TLS_OUT_OF_INDEXES) {
	xmlGlobalStateCleanupHelperParams * p;
	EnterCriticalSection(&cleanup_helpers_cs);
	p = cleanup_helpers_head;
	while (p != NULL) {
		xmlGlobalStateCleanupHelperParams * temp = p;
		p = p->next;
		xmlFreeGlobalState(temp->memory);
		free(temp);
	}
	cleanup_helpers_head = 0;
	LeaveCriticalSection(&cleanup_helpers_cs);
	TlsFree(globalkey);
	globalkey = TLS_OUT_OF_INDEXES;
    }
    DeleteCriticalSection(&cleanup_helpers_cs);
#endif
}

#ifdef LIBXML_THREAD_ENABLED
/**
 * xmlOnceInit
 *
 * xmlOnceInit() is used to initialize the value of mainthread for use
 * in other routines. This function should only be called using
 * pthread_once() in association with the once_control variable to ensure
 * that the function is only called once. See man pthread_once for more
 * details.
 */
static void
xmlOnceInit(void) {
#ifdef HAVE_PTHREAD_H
    (void) pthread_key_create(&globalkey, xmlFreeGlobalState);
    mainthread = pthread_self();
#endif

#if defined(HAVE_WIN32_THREADS)
#if !defined(HAVE_COMPILER_TLS)
    globalkey = TlsAlloc();
#endif
    mainthread = GetCurrentThreadId();
#endif

#ifdef HAVE_BEOS_THREADS
	if (atomic_add(&run_once_init, 1) == 0) {
		globalkey = tls_allocate();
		tls_set(globalkey, NULL);
		mainthread = find_thread(NULL);
	} else
		atomic_add(&run_once_init, -1);
#endif
}
#endif

/**
 * DllMain:
 * @hinstDLL: handle to DLL instance
 * @fdwReason: Reason code for entry
 * @lpvReserved: generic pointer (depends upon reason code)
 *
 * Entry point for Windows library. It is being used to free thread-specific
 * storage.
 *
 * Returns TRUE always
 */
#if defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) || defined(LIBXML_STATIC_FOR_DLL))
#if defined(LIBXML_STATIC_FOR_DLL)
BOOL WINAPI xmlDllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) 
#else
BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) 
#endif
{
    switch(fdwReason) {
    case DLL_THREAD_DETACH:
	if (globalkey != TLS_OUT_OF_INDEXES) {
	    xmlGlobalState *globalval = NULL;
	    xmlGlobalStateCleanupHelperParams * p =
		(xmlGlobalStateCleanupHelperParams*)TlsGetValue(globalkey);
	    globalval = (xmlGlobalState *)(p ? p->memory : NULL);
            if (globalval) {
                xmlFreeGlobalState(globalval);
                TlsSetValue(globalkey,NULL);
            }
	    if (p)
	    {
		EnterCriticalSection(&cleanup_helpers_cs);
                if (p == cleanup_helpers_head)
		    cleanup_helpers_head = p->next;
                else
		    p->prev->next = p->next;
                if (p->next != NULL)
                    p->next->prev = p->prev;
		LeaveCriticalSection(&cleanup_helpers_cs);
		free(p);
	    }
	}
	break;
    }
    return TRUE;
}
#endif