444 lines
10 KiB
C
444 lines
10 KiB
C
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/* This code implemented by Dag.Gruneau@elsa.preseco.comm.se */
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/* Fast NonRecursiveMutex support by Yakov Markovitch, markovitch@iso.ru */
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/* Eliminated some memory leaks, gsw@agere.com */
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#include <windows.h>
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#include <limits.h>
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#ifdef HAVE_PROCESS_H
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#include <process.h>
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#endif
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/* options */
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#ifndef _PY_USE_CV_LOCKS
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#define _PY_USE_CV_LOCKS 1 /* use locks based on cond vars */
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#endif
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/* Now, define a non-recursive mutex using either condition variables
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* and critical sections (fast) or using operating system mutexes
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* (slow)
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*/
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#if _PY_USE_CV_LOCKS
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#include "condvar.h"
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typedef struct _NRMUTEX
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{
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PyMUTEX_T cs;
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PyCOND_T cv;
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int locked;
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} NRMUTEX;
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typedef NRMUTEX *PNRMUTEX;
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PNRMUTEX
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AllocNonRecursiveMutex()
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{
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PNRMUTEX m = (PNRMUTEX)malloc(sizeof(NRMUTEX));
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if (!m)
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return NULL;
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if (PyCOND_INIT(&m->cv))
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goto fail;
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if (PyMUTEX_INIT(&m->cs)) {
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PyCOND_FINI(&m->cv);
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goto fail;
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}
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m->locked = 0;
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return m;
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fail:
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free(m);
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return NULL;
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}
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VOID
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FreeNonRecursiveMutex(PNRMUTEX mutex)
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{
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if (mutex) {
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PyCOND_FINI(&mutex->cv);
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PyMUTEX_FINI(&mutex->cs);
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free(mutex);
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}
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}
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DWORD
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EnterNonRecursiveMutex(PNRMUTEX mutex, DWORD milliseconds)
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{
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DWORD result = WAIT_OBJECT_0;
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if (PyMUTEX_LOCK(&mutex->cs))
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return WAIT_FAILED;
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if (milliseconds == INFINITE) {
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while (mutex->locked) {
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if (PyCOND_WAIT(&mutex->cv, &mutex->cs)) {
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result = WAIT_FAILED;
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break;
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}
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}
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} else if (milliseconds != 0) {
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/* wait at least until the target */
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DWORD now, target = GetTickCount() + milliseconds;
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while (mutex->locked) {
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if (PyCOND_TIMEDWAIT(&mutex->cv, &mutex->cs, milliseconds*1000) < 0) {
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result = WAIT_FAILED;
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break;
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}
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now = GetTickCount();
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if (target <= now)
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break;
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milliseconds = target-now;
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}
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}
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if (!mutex->locked) {
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mutex->locked = 1;
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result = WAIT_OBJECT_0;
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} else if (result == WAIT_OBJECT_0)
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result = WAIT_TIMEOUT;
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/* else, it is WAIT_FAILED */
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PyMUTEX_UNLOCK(&mutex->cs); /* must ignore result here */
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return result;
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}
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BOOL
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LeaveNonRecursiveMutex(PNRMUTEX mutex)
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{
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BOOL result;
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if (PyMUTEX_LOCK(&mutex->cs))
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return FALSE;
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mutex->locked = 0;
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result = PyCOND_SIGNAL(&mutex->cv);
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result &= PyMUTEX_UNLOCK(&mutex->cs);
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return result;
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}
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#else /* if ! _PY_USE_CV_LOCKS */
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/* NR-locks based on a kernel mutex */
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#define PNRMUTEX HANDLE
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PNRMUTEX
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AllocNonRecursiveMutex()
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{
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return CreateSemaphore(NULL, 1, 1, NULL);
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}
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VOID
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FreeNonRecursiveMutex(PNRMUTEX mutex)
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{
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/* No in-use check */
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CloseHandle(mutex);
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}
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DWORD
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EnterNonRecursiveMutex(PNRMUTEX mutex, DWORD milliseconds)
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{
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return WaitForSingleObject(mutex, milliseconds);
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}
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BOOL
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LeaveNonRecursiveMutex(PNRMUTEX mutex)
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{
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return ReleaseSemaphore(mutex, 1, NULL);
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}
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#endif /* _PY_USE_CV_LOCKS */
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long PyThread_get_thread_ident(void);
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/*
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* Initialization of the C package, should not be needed.
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*/
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static void
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PyThread__init_thread(void)
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{
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}
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/*
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* Thread support.
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*/
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typedef struct {
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void (*func)(void*);
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void *arg;
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} callobj;
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/* thunker to call adapt between the function type used by the system's
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thread start function and the internally used one. */
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#if defined(MS_WINCE)
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static DWORD WINAPI
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#else
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static unsigned __stdcall
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#endif
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bootstrap(void *call)
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{
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callobj *obj = (callobj*)call;
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void (*func)(void*) = obj->func;
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void *arg = obj->arg;
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HeapFree(GetProcessHeap(), 0, obj);
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func(arg);
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return 0;
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}
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long
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PyThread_start_new_thread(void (*func)(void *), void *arg)
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{
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HANDLE hThread;
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unsigned threadID;
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callobj *obj;
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dprintf(("%ld: PyThread_start_new_thread called\n",
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PyThread_get_thread_ident()));
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if (!initialized)
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PyThread_init_thread();
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obj = (callobj*)HeapAlloc(GetProcessHeap(), 0, sizeof(*obj));
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if (!obj)
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return -1;
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obj->func = func;
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obj->arg = arg;
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#if defined(MS_WINCE)
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hThread = CreateThread(NULL,
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Py_SAFE_DOWNCAST(_pythread_stacksize, Py_ssize_t, SIZE_T),
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bootstrap, obj, 0, &threadID);
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#else
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hThread = (HANDLE)_beginthreadex(0,
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Py_SAFE_DOWNCAST(_pythread_stacksize,
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Py_ssize_t, unsigned int),
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bootstrap, obj,
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0, &threadID);
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#endif
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if (hThread == 0) {
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#if defined(MS_WINCE)
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/* Save error in variable, to prevent PyThread_get_thread_ident
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from clobbering it. */
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unsigned e = GetLastError();
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dprintf(("%ld: PyThread_start_new_thread failed, win32 error code %u\n",
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PyThread_get_thread_ident(), e));
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#else
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/* I've seen errno == EAGAIN here, which means "there are
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* too many threads".
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*/
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int e = errno;
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dprintf(("%ld: PyThread_start_new_thread failed, errno %d\n",
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PyThread_get_thread_ident(), e));
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#endif
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threadID = (unsigned)-1;
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HeapFree(GetProcessHeap(), 0, obj);
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}
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else {
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dprintf(("%ld: PyThread_start_new_thread succeeded: %p\n",
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PyThread_get_thread_ident(), (void*)hThread));
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CloseHandle(hThread);
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}
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return (long) threadID;
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}
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/*
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* Return the thread Id instead of an handle. The Id is said to uniquely identify the
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* thread in the system
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*/
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long
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PyThread_get_thread_ident(void)
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{
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if (!initialized)
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PyThread_init_thread();
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return GetCurrentThreadId();
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}
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void
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PyThread_exit_thread(void)
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{
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dprintf(("%ld: PyThread_exit_thread called\n", PyThread_get_thread_ident()));
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if (!initialized)
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exit(0);
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#if defined(MS_WINCE)
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ExitThread(0);
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#else
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_endthreadex(0);
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#endif
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}
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/*
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* Lock support. It has too be implemented as semaphores.
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* I [Dag] tried to implement it with mutex but I could find a way to
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* tell whether a thread already own the lock or not.
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*/
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PyThread_type_lock
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PyThread_allocate_lock(void)
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{
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PNRMUTEX aLock;
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dprintf(("PyThread_allocate_lock called\n"));
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if (!initialized)
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PyThread_init_thread();
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aLock = AllocNonRecursiveMutex() ;
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dprintf(("%ld: PyThread_allocate_lock() -> %p\n", PyThread_get_thread_ident(), aLock));
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return (PyThread_type_lock) aLock;
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}
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void
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PyThread_free_lock(PyThread_type_lock aLock)
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{
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dprintf(("%ld: PyThread_free_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
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FreeNonRecursiveMutex(aLock) ;
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}
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/*
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* Return 1 on success if the lock was acquired
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*
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* and 0 if the lock was not acquired. This means a 0 is returned
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* if the lock has already been acquired by this thread!
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*/
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PyLockStatus
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PyThread_acquire_lock_timed(PyThread_type_lock aLock,
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PY_TIMEOUT_T microseconds, int intr_flag)
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{
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/* Fow now, intr_flag does nothing on Windows, and lock acquires are
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* uninterruptible. */
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PyLockStatus success;
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PY_TIMEOUT_T milliseconds;
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if (microseconds >= 0) {
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milliseconds = microseconds / 1000;
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if (microseconds % 1000 > 0)
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++milliseconds;
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if ((DWORD) milliseconds != milliseconds)
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Py_FatalError("Timeout too large for a DWORD, "
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"please check PY_TIMEOUT_MAX");
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}
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else
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milliseconds = INFINITE;
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dprintf(("%ld: PyThread_acquire_lock_timed(%p, %lld) called\n",
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PyThread_get_thread_ident(), aLock, microseconds));
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if (aLock && EnterNonRecursiveMutex((PNRMUTEX)aLock,
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(DWORD)milliseconds) == WAIT_OBJECT_0) {
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success = PY_LOCK_ACQUIRED;
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}
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else {
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success = PY_LOCK_FAILURE;
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}
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dprintf(("%ld: PyThread_acquire_lock(%p, %lld) -> %d\n",
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PyThread_get_thread_ident(), aLock, microseconds, success));
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return success;
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}
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int
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PyThread_acquire_lock(PyThread_type_lock aLock, int waitflag)
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{
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return PyThread_acquire_lock_timed(aLock, waitflag ? -1 : 0, 0);
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}
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void
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PyThread_release_lock(PyThread_type_lock aLock)
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{
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dprintf(("%ld: PyThread_release_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
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if (!(aLock && LeaveNonRecursiveMutex((PNRMUTEX) aLock)))
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dprintf(("%ld: Could not PyThread_release_lock(%p) error: %ld\n", PyThread_get_thread_ident(), aLock, GetLastError()));
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}
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/* minimum/maximum thread stack sizes supported */
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#define THREAD_MIN_STACKSIZE 0x8000 /* 32kB */
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#define THREAD_MAX_STACKSIZE 0x10000000 /* 256MB */
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/* set the thread stack size.
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* Return 0 if size is valid, -1 otherwise.
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*/
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static int
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_pythread_nt_set_stacksize(size_t size)
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{
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/* set to default */
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if (size == 0) {
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_pythread_stacksize = 0;
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return 0;
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}
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/* valid range? */
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if (size >= THREAD_MIN_STACKSIZE && size < THREAD_MAX_STACKSIZE) {
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_pythread_stacksize = size;
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return 0;
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}
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return -1;
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}
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#define THREAD_SET_STACKSIZE(x) _pythread_nt_set_stacksize(x)
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/* use native Windows TLS functions */
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#define Py_HAVE_NATIVE_TLS
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#ifdef Py_HAVE_NATIVE_TLS
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int
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PyThread_create_key(void)
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{
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DWORD result= TlsAlloc();
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if (result == TLS_OUT_OF_INDEXES)
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return -1;
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return (int)result;
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}
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void
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PyThread_delete_key(int key)
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{
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TlsFree(key);
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}
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/* We must be careful to emulate the strange semantics implemented in thread.c,
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* where the value is only set if it hasn't been set before.
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*/
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int
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PyThread_set_key_value(int key, void *value)
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{
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BOOL ok;
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void *oldvalue;
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assert(value != NULL);
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oldvalue = TlsGetValue(key);
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if (oldvalue != NULL)
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/* ignore value if already set */
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return 0;
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ok = TlsSetValue(key, value);
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if (!ok)
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return -1;
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return 0;
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}
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void *
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PyThread_get_key_value(int key)
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{
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/* because TLS is used in the Py_END_ALLOW_THREAD macro,
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* it is necessary to preserve the windows error state, because
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* it is assumed to be preserved across the call to the macro.
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* Ideally, the macro should be fixed, but it is simpler to
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* do it here.
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*/
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DWORD error = GetLastError();
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void *result = TlsGetValue(key);
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SetLastError(error);
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return result;
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}
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void
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PyThread_delete_key_value(int key)
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{
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/* NULL is used as "key missing", and it is also the default
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* given by TlsGetValue() if nothing has been set yet.
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*/
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TlsSetValue(key, NULL);
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}
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/* reinitialization of TLS is not necessary after fork when using
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* the native TLS functions. And forking isn't supported on Windows either.
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*/
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void
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PyThread_ReInitTLS(void)
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{}
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#endif
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