python/Python/thread_nt.h at master · filippsen/python · GitHub

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

/* Fast NonRecursiveMutex support by Yakov Markovitch, markovitch@iso.ru */

/* Eliminated some memory leaks, gsw@agere.com */

#include <windows.h>

#include <limits.h>

#ifdef HAVE_PROCESS_H

#include <process.h>

#endif

typedef struct NRMUTEX {

LONG owned ;

DWORD thread_id ;

HANDLE hevent ;

} NRMUTEX, *PNRMUTEX ;

BOOL

InitializeNonRecursiveMutex(PNRMUTEX mutex)

{

mutex->owned = -1 ; /* No threads have entered NonRecursiveMutex */

mutex->thread_id = 0 ;

mutex->hevent = CreateEvent(NULL, FALSE, FALSE, NULL) ;

return mutex->hevent != NULL ; /* TRUE if the mutex is created */

}

VOID

DeleteNonRecursiveMutex(PNRMUTEX mutex)

{

/* No in-use check */

CloseHandle(mutex->hevent) ;

mutex->hevent = NULL ; /* Just in case */

}

DWORD

EnterNonRecursiveMutex(PNRMUTEX mutex, BOOL wait)

{

/* Assume that the thread waits successfully */

DWORD ret ;

/* InterlockedIncrement(&mutex->owned) == 0 means that no thread currently owns the mutex */

if (!wait)

{

if (InterlockedCompareExchange(&mutex->owned, 0, -1) != -1)

return WAIT_TIMEOUT ;

ret = WAIT_OBJECT_0 ;

}

else

ret = InterlockedIncrement(&mutex->owned) ?

/* Some thread owns the mutex, let's wait... */

WaitForSingleObject(mutex->hevent, INFINITE) : WAIT_OBJECT_0 ;

mutex->thread_id = GetCurrentThreadId() ; /* We own it */

return ret ;

}

BOOL

LeaveNonRecursiveMutex(PNRMUTEX mutex)

{

/* We don't own the mutex */

mutex->thread_id = 0 ;

return

InterlockedDecrement(&mutex->owned) < 0 ||

SetEvent(mutex->hevent) ; /* Other threads are waiting, wake one on them up */

}

PNRMUTEX

AllocNonRecursiveMutex(void)

{

PNRMUTEX mutex = (PNRMUTEX)malloc(sizeof(NRMUTEX)) ;

if (mutex && !InitializeNonRecursiveMutex(mutex))

{

free(mutex) ;

mutex = NULL ;

}

return mutex ;

}

void

FreeNonRecursiveMutex(PNRMUTEX mutex)

{

if (mutex)

{

DeleteNonRecursiveMutex(mutex) ;

free(mutex) ;

}

long PyThread_get_thread_ident(void);

* Initialization of the C package, should not be needed.

static void

PyThread__init_thread(void)

{

}

* Thread support.

typedef struct {

void (*func)(void*);

void *arg;

} callobj;

/* thunker to call adapt between the function type used by the system's

thread start function and the internally used one. */

#if defined(MS_WINCE)

static DWORD WINAPI

#else

static unsigned __stdcall

#endif

bootstrap(void *call)

{

callobj *obj = (callobj*)call;

void (*func)(void*) = obj->func;

void *arg = obj->arg;

HeapFree(GetProcessHeap(), 0, obj);

func(arg);

return 0;

}

long

PyThread_start_new_thread(void (*func)(void *), void *arg)

{

HANDLE hThread;

unsigned threadID;

callobj *obj;

dprintf(("%ld: PyThread_start_new_thread called\n",

PyThread_get_thread_ident()));

if (!initialized)

PyThread_init_thread();

obj = (callobj*)HeapAlloc(GetProcessHeap(), 0, sizeof(*obj));

if (!obj)

return -1;

obj->func = func;

obj->arg = arg;

#if defined(MS_WINCE)

hThread = CreateThread(NULL,

Py_SAFE_DOWNCAST(_pythread_stacksize, Py_ssize_t, SIZE_T),

bootstrap, obj, 0, &threadID);

#else

hThread = (HANDLE)_beginthreadex(0,

Py_SAFE_DOWNCAST(_pythread_stacksize,

Py_ssize_t, unsigned int),

bootstrap, obj,

0, &threadID);

#endif

if (hThread == 0) {

#if defined(MS_WINCE)

/* Save error in variable, to prevent PyThread_get_thread_ident

from clobbering it. */

unsigned e = GetLastError();

dprintf(("%ld: PyThread_start_new_thread failed, win32 error code %u\n",

PyThread_get_thread_ident(), e));

#else

/* I've seen errno == EAGAIN here, which means "there are

* too many threads".

int e = errno;

dprintf(("%ld: PyThread_start_new_thread failed, errno %d\n",

PyThread_get_thread_ident(), e));

#endif

threadID = (unsigned)-1;

HeapFree(GetProcessHeap(), 0, obj);

}

else {

dprintf(("%ld: PyThread_start_new_thread succeeded: %p\n",

PyThread_get_thread_ident(), (void*)hThread));

CloseHandle(hThread);

}

return (long) threadID;

}

* 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();

}

void

PyThread_exit_thread(void)

{

dprintf(("%ld: PyThread_exit_thread called\n", PyThread_get_thread_ident()));

if (!initialized)

exit(0);

#if defined(MS_WINCE)

ExitThread(0);

#else

_endthreadex(0);

#endif

}

#ifndef NO_EXIT_PROG

void

PyThread_exit_prog(int status)

{

dprintf(("PyThread_exit_prog(%d) called\n", status));

if (!initialized)

exit(status);

}

#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)

{

PNRMUTEX aLock;

dprintf(("PyThread_allocate_lock called\n"));

if (!initialized)

PyThread_init_thread();

aLock = AllocNonRecursiveMutex() ;

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

return (PyThread_type_lock) aLock;

}

void

PyThread_free_lock(PyThread_type_lock aLock)

{

dprintf(("%ld: PyThread_free_lock(%p) called\n", PyThread_get_thread_ident(),aLock));

FreeNonRecursiveMutex(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 ;

dprintf(("%ld: PyThread_acquire_lock(%p, %d) called\n", PyThread_get_thread_ident(),aLock, waitflag));

success = aLock && EnterNonRecursiveMutex((PNRMUTEX) aLock, (waitflag ? INFINITE : 0)) == WAIT_OBJECT_0 ;

dprintf(("%ld: PyThread_acquire_lock(%p, %d) -> %d\n", PyThread_get_thread_ident(),aLock, waitflag, success));

return success;

}

void

PyThread_release_lock(PyThread_type_lock aLock)

{

dprintf(("%ld: PyThread_release_lock(%p) called\n", PyThread_get_thread_ident(),aLock));

if (!(aLock && LeaveNonRecursiveMutex((PNRMUTEX) aLock)))

dprintf(("%ld: Could not PyThread_release_lock(%p) error: %ld\n", PyThread_get_thread_ident(), aLock, GetLastError()));

}

/* minimum/maximum thread stack sizes supported */

#define THREAD_MIN_STACKSIZE 0x8000 /* 32kB */

#define THREAD_MAX_STACKSIZE 0x10000000 /* 256MB */

/* set the thread stack size.

* Return 0 if size is valid, -1 otherwise.

static int

_pythread_nt_set_stacksize(size_t size)

{

/* set to default */

if (size == 0) {

_pythread_stacksize = 0;

return 0;

}

/* valid range? */

if (size >= THREAD_MIN_STACKSIZE && size < THREAD_MAX_STACKSIZE) {

_pythread_stacksize = size;

return 0;

}

return -1;

}

#define THREAD_SET_STACKSIZE(x) _pythread_nt_set_stacksize(x)

/* use native Windows TLS functions */

#define Py_HAVE_NATIVE_TLS

#ifdef Py_HAVE_NATIVE_TLS

int

PyThread_create_key(void)

{

return (int) TlsAlloc();

}

void

PyThread_delete_key(int key)

{

TlsFree(key);

}

/* We must be careful to emulate the strange semantics implemented in thread.c,

* where the value is only set if it hasn't been set before.

int

PyThread_set_key_value(int key, void *value)

{

BOOL ok;

void *oldvalue;

assert(value != NULL);

oldvalue = TlsGetValue(key);

if (oldvalue != NULL)

/* ignore value if already set */

return 0;

ok = TlsSetValue(key, value);

if (!ok)

return -1;

return 0;

}

void *

PyThread_get_key_value(int key)

{

/* because TLS is used in the Py_END_ALLOW_THREAD macro,

* it is necessary to preserve the windows error state, because

* it is assumed to be preserved across the call to the macro.

* Ideally, the macro should be fixed, but it is simpler to

* do it here.

DWORD error = GetLastError();

void *result = TlsGetValue(key);

SetLastError(error);

return result;

}

void

PyThread_delete_key_value(int key)

{

/* NULL is used as "key missing", and it is also the default

* given by TlsGetValue() if nothing has been set yet.

TlsSetValue(key, NULL);

}

/* reinitialization of TLS is not necessary after fork when using

* the native TLS functions. And forking isn't supported on Windows either.

void

PyThread_ReInitTLS(void)

{}

#endif

python/Python/thread_nt.h at master · filippsen/python · GitHub

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