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-rw-r--r--mysys/my_winsem.c406
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diff --git a/mysys/my_winsem.c b/mysys/my_winsem.c
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+/*
+ * -------------------------------------------------------------
+ *
+ * Module: my_semaphore.c (Original: semaphore.c from pthreads library)
+ *
+ * Purpose:
+ * Semaphores aren't actually part of the PThreads standard.
+ * They are defined by the POSIX Standard:
+ *
+ * POSIX 1003.1b-1993 (POSIX.1b)
+ *
+ * -------------------------------------------------------------
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright (C) 1998
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA
+ */
+
+/*
+ NEED_SEM is not used in MySQL and should only be needed under
+ Windows CE.
+
+ The big changes compared to the original version was to not allocate
+ any additional memory in sem_init() but to instead store everthing
+ we need in sem_t.
+
+ TODO:
+ To get HAVE_CREATESEMAPHORE we have to define the struct
+ in my_semaphore.h
+*/
+
+#include "mysys_priv.h"
+#ifdef __WIN__
+#include "my_semaphore.h"
+#include <errno.h>
+
+/*
+ DOCPUBLIC
+ This function initializes an unnamed semaphore. the
+ initial value of the semaphore is 'value'
+
+ PARAMETERS
+ sem Pointer to an instance of sem_t
+
+ pshared If zero, this semaphore may only be shared between
+ threads in the same process.
+ If nonzero, the semaphore can be shared between
+ processes
+
+ value Initial value of the semaphore counter
+
+ RESULTS
+ 0 Successfully created semaphore,
+ -1 Failed, error in errno
+
+ ERRNO
+ EINVAL 'sem' is not a valid semaphore,
+ ENOSPC A required resource has been exhausted,
+ ENOSYS Semaphores are not supported,
+ EPERM The process lacks appropriate privilege
+
+*/
+
+int
+sem_init (sem_t *sem, int pshared, unsigned int value)
+{
+ int result = 0;
+
+ if (pshared != 0)
+ {
+ /*
+ We don't support creating a semaphore that can be shared between
+ processes
+ */
+ result = EPERM;
+ }
+ else
+ {
+#ifndef HAVE_CREATESEMAPHORE
+ sem->value = value;
+ sem->event = CreateEvent(NULL,
+ FALSE, /* manual reset */
+ FALSE, /* initial state */
+ NULL);
+ if (!sem->event)
+ result = ENOSPC;
+ else
+ {
+ if (value)
+ SetEvent(sem->event);
+ InitializeCriticalSection(&sem->sem_lock_cs);
+ }
+#else /* HAVE_CREATESEMAPHORE */
+ *sem = CreateSemaphore (NULL, /* Always NULL */
+ value, /* Initial value */
+ 0x7FFFFFFFL, /* Maximum value */
+ NULL); /* Name */
+ if (!*sem)
+ result = ENOSPC;
+#endif /* HAVE_CREATESEMAPHORE */
+ }
+ if (result != 0)
+ {
+ errno = result;
+ return -1;
+ }
+ return 0;
+} /* sem_init */
+
+
+/*
+ DOCPUBLIC
+ This function destroys an unnamed semaphore.
+
+ PARAMETERS
+ sem Pointer to an instance of sem_t
+
+ RESULTS
+ 0 Successfully destroyed semaphore,
+ -1 Failed, error in errno
+ ERRNO
+ EINVAL 'sem' is not a valid semaphore,
+ ENOSYS Semaphores are not supported,
+ EBUSY Threads (or processes) are currently blocked on 'sem'
+*/
+
+int
+sem_destroy (sem_t * sem)
+{
+ int result = 0;
+
+#ifdef EXTRA_DEBUG
+ if (sem == NULL || *sem == NULL)
+ {
+ errno=EINVAL;
+ return;
+ }
+#endif /* EXTRA_DEBUG */
+
+#ifndef HAVE_CREATESEMAPHORE
+ if (! CloseHandle(sem->event))
+ result = EINVAL;
+ else
+ DeleteCriticalSection(&sem->sem_lock_cs);
+#else /* HAVE_CREATESEMAPHORE */
+ if (!CloseHandle(*sem))
+ result = EINVAL;
+#endif /* HAVE_CREATESEMAPHORE */
+ if (result)
+ {
+ errno = result;
+ return -1;
+ }
+ *sem=0; /* Safety */
+ return 0;
+} /* sem_destroy */
+
+
+/*
+ DOCPUBLIC
+ This function tries to wait on a semaphore. If the
+ semaphore value is greater than zero, it decreases
+ its value by one. If the semaphore value is zero, then
+ this function returns immediately with the error EAGAIN
+
+ PARAMETERS
+ sem Pointer to an instance of sem_t
+
+ RESULTS
+ 0 Successfully decreased semaphore,
+ -1 Failed, error in errno
+
+ ERRNO
+ EAGAIN The semaphore was already locked,
+ EINVAL 'sem' is not a valid semaphore,
+ ENOSYS Semaphores are not supported,
+ EINTR The function was interrupted by a signal,
+ EDEADLK A deadlock condition was detected.
+*/
+
+int
+sem_trywait(sem_t * sem)
+{
+#ifndef HAVE_CREATESEMAPHORE
+ /* not yet implemented! */
+ int errno = EINVAL;
+ return -1;
+#else /* HAVE_CREATESEMAPHORE */
+#ifdef EXTRA_DEBUG
+ if (sem == NULL || *sem == NULL)
+ {
+ errno=EINVAL;
+ return -1;
+ }
+#endif /* EXTRA_DEBUG */
+ if (WaitForSingleObject (*sem, 0) == WAIT_TIMEOUT)
+ {
+ errno= EAGAIN;
+ return -1;
+ }
+ return 0;
+#endif /* HAVE_CREATESEMAPHORE */
+
+} /* sem_trywait */
+
+
+#ifndef HAVE_CREATESEMAPHORE
+
+static void
+ptw32_decrease_semaphore(sem_t * sem)
+{
+ EnterCriticalSection(&sem->sem_lock_cs);
+ DBUG_ASSERT(sem->value != 0);
+ sem->value--;
+ if (sem->value != 0)
+ SetEvent(sem->event);
+ LeaveCriticalSection(&sem->sem_lock_cs);
+}
+
+static BOOL
+ptw32_increase_semaphore(sem_t * sem, unsigned int n)
+{
+ BOOL result=FALSE;
+
+ EnterCriticalSection(&sem->sem_lock_cs);
+ if (sem->value + n > sem->value)
+ {
+ sem->value += n;
+ SetEvent(sem->event);
+ result = TRUE;
+ }
+ LeaveCriticalSection(&sem->sem_lock_cs);
+ return result;
+}
+
+#endif /* HAVE_CREATESEMAPHORE */
+
+
+/*
+ ------------------------------------------------------
+ DOCPUBLIC
+ This function waits on a semaphore. If the
+ semaphore value is greater than zero, it decreases
+ its value by one. If the semaphore value is zero, then
+ the calling thread (or process) is blocked until it can
+ successfully decrease the value or until interrupted by
+ a signal.
+
+ PARAMETERS
+ sem Pointer to an instance of sem_t
+
+ RESULTS
+ 0 Successfully decreased semaphore,
+ -1 Failed, error in errno
+
+ ERRNO
+ EINVAL 'Sem' is not a valid semaphore,
+ ENOSYS Semaphores are not supported,
+ EINTR The function was interrupted by a signal,
+ EDEADLK A deadlock condition was detected.
+*/
+
+int
+sem_wait(sem_t *sem)
+{
+ int result;
+
+#ifdef EXTRA_DEBUG
+ if (sem == NULL || *sem == NULL)
+ {
+ errno=EINVAL;
+ return -1;
+ }
+#endif /* EXTRA_DEBUG */
+
+#ifndef HAVE_CREATESEMAPHORE
+ result=WaitForSingleObject(sem->event, INFINITE);
+#else
+ result=WaitForSingleObject(*sem, INFINITE);
+#endif
+ if (result == WAIT_FAILED || result == WAIT_ABANDONED_0)
+ result = EINVAL;
+ else if (result == WAIT_TIMEOUT)
+ result = ETIMEDOUT;
+ else
+ result=0;
+ if (result)
+ {
+ errno = result;
+ return -1;
+ }
+#ifndef HAVE_CREATESEMAPHORE
+ ptw32_decrease_semaphore(sem);
+#endif /* HAVE_CREATESEMAPHORE */
+ return 0;
+}
+
+
+/*
+ ------------------------------------------------------
+ DOCPUBLIC
+ This function posts a wakeup to a semaphore. If there
+ are waiting threads (or processes), one is awakened;
+ otherwise, the semaphore value is incremented by one.
+
+ PARAMETERS
+ sem Pointer to an instance of sem_t
+
+ RESULTS
+ 0 Successfully posted semaphore,
+ -1 Failed, error in errno
+
+ ERRNO
+ EINVAL 'sem' is not a valid semaphore,
+ ENOSYS Semaphores are not supported,
+
+*/
+
+int
+sem_post (sem_t * sem)
+{
+#ifdef EXTRA_DEBUG
+ if (sem == NULL || *sem == NULL)
+ {
+ errno=EINVAL;
+ return -1;
+ }
+#endif /* EXTRA_DEBUG */
+
+#ifndef HAVE_CREATESEMAPHORE
+ if (! ptw32_increase_semaphore(sem, 1))
+#else /* HAVE_CREATESEMAPHORE */
+ if (! ReleaseSemaphore(*sem, 1, 0))
+#endif /* HAVE_CREATESEMAPHORE */
+ {
+ errno=EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+
+/*
+ ------------------------------------------------------
+ DOCPUBLIC
+ This function posts multiple wakeups to a semaphore. If there
+ are waiting threads (or processes), n <= count are awakened;
+ the semaphore value is incremented by count - n.
+
+ PARAMETERS
+ sem Pointer to an instance of sem_t
+ count Counter, must be greater than zero.
+
+ RESULTS
+ 0 Successfully posted semaphore,
+ -1 Failed, error in errno
+
+ ERRNO
+ EINVAL 'sem' is not a valid semaphore or count is less
+ than or equal to zero.
+*/
+
+int
+sem_post_multiple (sem_t * sem, unsigned int count)
+{
+#ifdef EXTRA_DEBUG
+ if (sem == NULL || *sem == NULL || count <= 0)
+ {
+ errno=EINVAL;
+ return -1;
+ }
+#endif /* EXTRA_DEBUG */
+#ifndef HAVE_CREATESEMAPHORE
+ if (! ptw32_increase_semaphore (sem, count))
+#else /* HAVE_CREATESEMAPHORE */
+ if (! ReleaseSemaphore(*sem, count, 0))
+#endif /* HAVE_CREATESEMAPHORE */
+ {
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+int
+sem_getvalue (sem_t *sem, unsigned int *sval)
+{
+ errno = ENOSYS;
+ return -1;
+} /* sem_getvalue */
+
+#endif /* __WIN__ */
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