mirror of
https://github.com/python/cpython
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5b74badc8d
in order to have the same resolution as pthreads condition variables. At the same time, it must be large enough to accept 31 bits of milliseconds, which is the maximum timeout value in the windows API. A PY_LONG_LONG of microseconds fullfills both requirements. This closes issue #20737
435 lines
10 KiB
C
435 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)PyMem_RawMalloc(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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PyMem_RawFree(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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PyMem_RawFree(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, (PY_LONG_LONG)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 WaitForSingleObjectEx(mutex, milliseconds, FALSE);
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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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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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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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