44626dc7d5
This patch implements native to Windows subset of pthreads API used by Git. It allows to remove Pthreads for Win32 dependency for MSVC, msysgit and Cygwin. [J6t: If the MinGW build was built as part of the msysgit build environment, then threading was already enabled because the pthreads-win32 package is available in msysgit. With this patch, we can now enable threaded code unconditionally.] Signed-off-by: Andrzej K. Haczewski <ahaczewski@gmail.com> Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
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* Copyright (C) 2009 Andrzej K. Haczewski <ahaczewski@gmail.com>
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*
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* DISCLAMER: The implementation is Git-specific, it is subset of original
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* Pthreads API, without lots of other features that Git doesn't use.
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* Git also makes sure that the passed arguments are valid, so there's
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* no need for double-checking.
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*/
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#include "../../git-compat-util.h"
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#include "pthread.h"
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#include <errno.h>
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#include <limits.h>
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static unsigned __stdcall win32_start_routine(void *arg)
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{
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pthread_t *thread = arg;
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thread->arg = thread->start_routine(thread->arg);
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return 0;
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}
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int pthread_create(pthread_t *thread, const void *unused,
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void *(*start_routine)(void*), void *arg)
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{
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thread->arg = arg;
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thread->start_routine = start_routine;
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thread->handle = (HANDLE)
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_beginthreadex(NULL, 0, win32_start_routine, thread, 0, NULL);
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if (!thread->handle)
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return errno;
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else
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return 0;
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}
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int win32_pthread_join(pthread_t *thread, void **value_ptr)
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{
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DWORD result = WaitForSingleObject(thread->handle, INFINITE);
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switch (result) {
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case WAIT_OBJECT_0:
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if (value_ptr)
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*value_ptr = thread->arg;
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return 0;
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case WAIT_ABANDONED:
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return EINVAL;
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default:
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return err_win_to_posix(GetLastError());
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}
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}
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int pthread_cond_init(pthread_cond_t *cond, const void *unused)
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{
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cond->waiters = 0;
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cond->sema = CreateSemaphore(NULL, 0, LONG_MAX, NULL);
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if (!cond->sema)
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die("CreateSemaphore() failed");
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return 0;
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}
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int pthread_cond_destroy(pthread_cond_t *cond)
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{
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CloseHandle(cond->sema);
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cond->sema = NULL;
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return 0;
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}
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int pthread_cond_wait(pthread_cond_t *cond, CRITICAL_SECTION *mutex)
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{
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InterlockedIncrement(&cond->waiters);
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/*
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* Unlock external mutex and wait for signal.
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* NOTE: we've held mutex locked long enough to increment
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* waiters count above, so there's no problem with
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* leaving mutex unlocked before we wait on semaphore.
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*/
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LeaveCriticalSection(mutex);
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/* let's wait - ignore return value */
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WaitForSingleObject(cond->sema, INFINITE);
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/* we're done waiting, so make sure we decrease waiters count */
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InterlockedDecrement(&cond->waiters);
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/* lock external mutex again */
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EnterCriticalSection(mutex);
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return 0;
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}
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int pthread_cond_signal(pthread_cond_t *cond)
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{
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/*
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* Access to waiters count is atomic; see "Interlocked Variable Access"
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* http://msdn.microsoft.com/en-us/library/ms684122(VS.85).aspx
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*/
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int have_waiters = cond->waiters > 0;
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/*
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* Signal only when there are waiters
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*/
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if (have_waiters)
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return ReleaseSemaphore(cond->sema, 1, NULL) ?
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0 : err_win_to_posix(GetLastError());
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else
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return 0;
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}
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