342 lines
9.3 KiB
C
342 lines
9.3 KiB
C
/***********************************************************
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Copyright (c) 2000, BeOpen.com.
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Copyright (c) 1995-2000, Corporation for National Research Initiatives.
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Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
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All rights reserved.
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See the file "Misc/COPYRIGHT" for information on usage and
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redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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******************************************************************/
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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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#include <windows.h>
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#include <limits.h>
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#include <process.h>
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typedef struct NRMUTEX {
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LONG owned ;
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DWORD thread_id ;
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HANDLE hevent ;
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} NRMUTEX, *PNRMUTEX ;
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typedef PVOID WINAPI interlocked_cmp_xchg_t(PVOID *dest, PVOID exc, PVOID comperand) ;
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/* Sorry mate, but we haven't got InterlockedCompareExchange in Win95! */
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static PVOID WINAPI interlocked_cmp_xchg(PVOID *dest, PVOID exc, PVOID comperand)
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{
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static LONG spinlock = 0 ;
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PVOID result ;
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DWORD dwSleep = 0;
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/* Acqire spinlock (yielding control to other threads if cant aquire for the moment) */
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while(InterlockedExchange(&spinlock, 1))
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{
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// Using Sleep(0) can cause a priority inversion.
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// Sleep(0) only yields the processor if there's
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// another thread of the same priority that's
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// ready to run. If a high-priority thread is
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// trying to acquire the lock, which is held by
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// a low-priority thread, then the low-priority
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// thread may never get scheduled and hence never
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// free the lock. NT attempts to avoid priority
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// inversions by temporarily boosting the priority
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// of low-priority runnable threads, but the problem
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// can still occur if there's a medium-priority
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// thread that's always runnable. If Sleep(1) is used,
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// then the thread unconditionally yields the CPU. We
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// only do this for the second and subsequent even
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// iterations, since a millisecond is a long time to wait
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// if the thread can be scheduled in again sooner
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// (~100,000 instructions).
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// Avoid priority inversion: 0, 1, 0, 1,...
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Sleep(dwSleep);
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dwSleep = !dwSleep;
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}
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result = *dest ;
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if (result == comperand)
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*dest = exc ;
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/* Release spinlock */
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spinlock = 0 ;
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return result ;
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} ;
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static interlocked_cmp_xchg_t *ixchg ;
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BOOL InitializeNonRecursiveMutex(PNRMUTEX mutex)
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{
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if (!ixchg)
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{
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/* Sorely, Win95 has no InterlockedCompareExchange API (Win98 has), so we have to use emulation */
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HANDLE kernel = GetModuleHandle("kernel32.dll") ;
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if (!kernel || (ixchg = (interlocked_cmp_xchg_t *)GetProcAddress(kernel, "InterlockedCompareExchange")) == NULL)
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ixchg = interlocked_cmp_xchg ;
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}
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mutex->owned = -1 ; /* No threads have entered NonRecursiveMutex */
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mutex->thread_id = 0 ;
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mutex->hevent = CreateEvent(NULL, FALSE, FALSE, NULL) ;
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return mutex->hevent != NULL ; /* TRUE if the mutex is created */
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}
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#ifdef InterlockedCompareExchange
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#undef InterlockedCompareExchange
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#endif
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#define InterlockedCompareExchange(dest,exchange,comperand) (ixchg((dest), (exchange), (comperand)))
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VOID DeleteNonRecursiveMutex(PNRMUTEX mutex)
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{
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/* No in-use check */
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CloseHandle(mutex->hevent) ;
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mutex->hevent = NULL ; /* Just in case */
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}
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DWORD EnterNonRecursiveMutex(PNRMUTEX mutex, BOOL wait)
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{
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/* Assume that the thread waits successfully */
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DWORD ret ;
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/* InterlockedIncrement(&mutex->owned) == 0 means that no thread currently owns the mutex */
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if (!wait)
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{
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if (InterlockedCompareExchange((PVOID *)&mutex->owned, (PVOID)0, (PVOID)-1) != (PVOID)-1)
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return WAIT_TIMEOUT ;
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ret = WAIT_OBJECT_0 ;
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}
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else
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ret = InterlockedIncrement(&mutex->owned) ?
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/* Some thread owns the mutex, let's wait... */
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WaitForSingleObject(mutex->hevent, INFINITE) : WAIT_OBJECT_0 ;
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mutex->thread_id = GetCurrentThreadId() ; /* We own it */
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return ret ;
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}
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BOOL LeaveNonRecursiveMutex(PNRMUTEX mutex)
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{
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/* We don't own the mutex */
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mutex->thread_id = 0 ;
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return
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InterlockedDecrement(&mutex->owned) < 0 ||
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SetEvent(mutex->hevent) ; /* Other threads are waiting, wake one on them up */
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}
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PNRMUTEX AllocNonRecursiveMutex(void)
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{
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PNRMUTEX mutex = (PNRMUTEX)malloc(sizeof(NRMUTEX)) ;
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if (mutex && !InitializeNonRecursiveMutex(mutex))
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{
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free(mutex) ;
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mutex = NULL ;
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}
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return mutex ;
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}
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void FreeNonRecursiveMutex(PNRMUTEX mutex)
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{
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if (mutex)
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{
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DeleteNonRecursiveMutex(mutex) ;
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free(mutex) ;
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}
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}
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long PyThread_get_thread_ident(void);
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/*
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* Change all headers to pure ANSI as no one will use K&R style on an
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* NT
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*/
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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 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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int PyThread_start_new_thread(void (*func)(void *), void *arg)
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{
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uintptr_t rv;
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int success = 0;
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dprintf(("%ld: PyThread_start_new_thread called\n", PyThread_get_thread_ident()));
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if (!initialized)
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PyThread_init_thread();
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rv = _beginthread(func, 0, arg); /* use default stack size */
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if (rv != -1) {
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success = 1;
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dprintf(("%ld: PyThread_start_new_thread succeeded: %p\n", PyThread_get_thread_ident(), rv));
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}
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return success;
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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 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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static void do_PyThread_exit_thread(int no_cleanup)
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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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if (no_cleanup)
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_exit(0);
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else
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exit(0);
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_endthread();
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}
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void PyThread_exit_thread(void)
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{
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do_PyThread_exit_thread(0);
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}
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void PyThread__exit_thread(void)
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{
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do_PyThread_exit_thread(1);
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}
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#ifndef NO_EXIT_PROG
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static void do_PyThread_exit_prog(int status, int no_cleanup)
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{
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dprintf(("PyThread_exit_prog(%d) called\n", status));
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if (!initialized)
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if (no_cleanup)
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_exit(status);
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else
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exit(status);
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}
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void PyThread_exit_prog(int status)
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{
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do_PyThread_exit_prog(status, 0);
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}
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void PyThread__exit_prog(int status)
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{
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do_PyThread_exit_prog(status, 1);
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}
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#endif /* NO_EXIT_PROG */
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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 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 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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int PyThread_acquire_lock(PyThread_type_lock aLock, int waitflag)
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{
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int success ;
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dprintf(("%ld: PyThread_acquire_lock(%p, %d) called\n", PyThread_get_thread_ident(),aLock, waitflag));
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success = aLock && EnterNonRecursiveMutex((PNRMUTEX) aLock, (waitflag == 1 ? INFINITE : 0)) == WAIT_OBJECT_0 ;
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dprintf(("%ld: PyThread_acquire_lock(%p, %d) -> %d\n", PyThread_get_thread_ident(),aLock, waitflag, success));
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return success;
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}
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void 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: %l\n", PyThread_get_thread_ident(), aLock, GetLastError()));
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}
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/*
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* Semaphore support.
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*/
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PyThread_type_sema PyThread_allocate_sema(int value)
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{
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HANDLE aSemaphore;
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dprintf(("%ld: PyThread_allocate_sema called\n", PyThread_get_thread_ident()));
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if (!initialized)
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PyThread_init_thread();
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aSemaphore = CreateSemaphore( NULL, /* Security attributes */
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value, /* Initial value */
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INT_MAX, /* Maximum value */
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NULL); /* Name of semaphore */
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dprintf(("%ld: PyThread_allocate_sema() -> %p\n", PyThread_get_thread_ident(), aSemaphore));
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return (PyThread_type_sema) aSemaphore;
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}
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void PyThread_free_sema(PyThread_type_sema aSemaphore)
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{
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dprintf(("%ld: PyThread_free_sema(%p) called\n", PyThread_get_thread_ident(), aSemaphore));
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CloseHandle((HANDLE) aSemaphore);
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}
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/*
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XXX must do something about waitflag
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*/
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int PyThread_down_sema(PyThread_type_sema aSemaphore, int waitflag)
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{
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DWORD waitResult;
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dprintf(("%ld: PyThread_down_sema(%p) called\n", PyThread_get_thread_ident(), aSemaphore));
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waitResult = WaitForSingleObject( (HANDLE) aSemaphore, INFINITE);
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dprintf(("%ld: PyThread_down_sema(%p) return: %l\n", PyThread_get_thread_ident(), aSemaphore, waitResult));
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return 0;
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}
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void PyThread_up_sema(PyThread_type_sema aSemaphore)
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{
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ReleaseSemaphore(
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(HANDLE) aSemaphore, /* Handle of semaphore */
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1, /* increment count by one */
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NULL); /* not interested in previous count */
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dprintf(("%ld: PyThread_up_sema(%p)\n", PyThread_get_thread_ident(), aSemaphore));
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}
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