cpython/Python/thread_nt.h

360 lines
8.6 KiB
C

/* 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 a 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
}
/*
* 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