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331 lines
8.8 KiB
C
331 lines
8.8 KiB
C
/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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/*****************************************************************************
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** The following is a simple implementation of posix conditions
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*****************************************************************************/
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#if defined(_WIN32)
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#undef SAFE_MUTEX /* Avoid safe_mutex redefinitions */
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#include "mysys_priv.h"
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#include <m_string.h>
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#include <process.h>
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#include <sys/timeb.h>
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/*
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Windows native condition variables. We use runtime loading / function
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pointers, because they are not available on XP
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*/
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/* Prototypes and function pointers for condition variable functions */
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typedef void (WINAPI * InitializeConditionVariableProc)
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(PCONDITION_VARIABLE ConditionVariable);
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typedef BOOL (WINAPI * SleepConditionVariableCSProc)
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(PCONDITION_VARIABLE ConditionVariable,
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PCRITICAL_SECTION CriticalSection,
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DWORD dwMilliseconds);
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typedef void (WINAPI * WakeAllConditionVariableProc)
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(PCONDITION_VARIABLE ConditionVariable);
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typedef void (WINAPI * WakeConditionVariableProc)
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(PCONDITION_VARIABLE ConditionVariable);
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static InitializeConditionVariableProc my_InitializeConditionVariable;
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static SleepConditionVariableCSProc my_SleepConditionVariableCS;
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static WakeAllConditionVariableProc my_WakeAllConditionVariable;
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static WakeConditionVariableProc my_WakeConditionVariable;
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/**
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Indicates if we have native condition variables,
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initialized first time pthread_cond_init is called.
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*/
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static BOOL have_native_conditions= FALSE;
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/**
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Check if native conditions can be used, load function pointers
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*/
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static void check_native_cond_availability(void)
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{
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HMODULE module= GetModuleHandle("kernel32");
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my_InitializeConditionVariable= (InitializeConditionVariableProc)
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GetProcAddress(module, "InitializeConditionVariable");
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my_SleepConditionVariableCS= (SleepConditionVariableCSProc)
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GetProcAddress(module, "SleepConditionVariableCS");
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my_WakeAllConditionVariable= (WakeAllConditionVariableProc)
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GetProcAddress(module, "WakeAllConditionVariable");
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my_WakeConditionVariable= (WakeConditionVariableProc)
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GetProcAddress(module, "WakeConditionVariable");
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if (my_InitializeConditionVariable)
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have_native_conditions= TRUE;
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}
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/**
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Convert abstime to milliseconds
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*/
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static DWORD get_milliseconds(const struct timespec *abstime)
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{
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struct timespec current_time;
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long long ms;
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if (abstime == NULL)
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return INFINITE;
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set_timespec_nsec(current_time, 0);
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ms= (abstime->tv_sec - current_time.tv_sec)*1000LL +
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(abstime->tv_nsec - current_time.tv_nsec)/1000000LL;
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if(ms < 0 )
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ms= 0;
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if(ms > UINT_MAX)
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ms= INFINITE;
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return (DWORD)ms;
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}
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/*
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Old (pre-vista) implementation using events
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*/
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static int legacy_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
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{
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cond->waiting= 0;
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InitializeCriticalSection(&cond->lock_waiting);
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cond->events[SIGNAL]= CreateEvent(NULL, /* no security */
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FALSE, /* auto-reset event */
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FALSE, /* non-signaled initially */
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NULL); /* unnamed */
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/* Create a manual-reset event. */
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cond->events[BROADCAST]= CreateEvent(NULL, /* no security */
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TRUE, /* manual-reset */
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FALSE, /* non-signaled initially */
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NULL); /* unnamed */
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cond->broadcast_block_event= CreateEvent(NULL, /* no security */
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TRUE, /* manual-reset */
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TRUE, /* signaled initially */
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NULL); /* unnamed */
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if( cond->events[SIGNAL] == NULL ||
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cond->events[BROADCAST] == NULL ||
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cond->broadcast_block_event == NULL )
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return ENOMEM;
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return 0;
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}
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static int legacy_cond_destroy(pthread_cond_t *cond)
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{
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DeleteCriticalSection(&cond->lock_waiting);
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if (CloseHandle(cond->events[SIGNAL]) == 0 ||
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CloseHandle(cond->events[BROADCAST]) == 0 ||
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CloseHandle(cond->broadcast_block_event) == 0)
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return EINVAL;
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return 0;
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}
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static int legacy_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
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struct timespec *abstime)
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{
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int result;
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DWORD timeout;
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timeout= get_milliseconds(abstime);
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/*
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Block access if previous broadcast hasn't finished.
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This is just for safety and should normally not
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affect the total time spent in this function.
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*/
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WaitForSingleObject(cond->broadcast_block_event, INFINITE);
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EnterCriticalSection(&cond->lock_waiting);
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cond->waiting++;
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LeaveCriticalSection(&cond->lock_waiting);
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LeaveCriticalSection(mutex);
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result= WaitForMultipleObjects(2, cond->events, FALSE, timeout);
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EnterCriticalSection(&cond->lock_waiting);
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cond->waiting--;
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if (cond->waiting == 0)
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{
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/*
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We're the last waiter to be notified or to stop waiting, so
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reset the manual event.
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*/
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/* Close broadcast gate */
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ResetEvent(cond->events[BROADCAST]);
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/* Open block gate */
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SetEvent(cond->broadcast_block_event);
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}
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LeaveCriticalSection(&cond->lock_waiting);
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EnterCriticalSection(mutex);
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return result == WAIT_TIMEOUT ? ETIMEDOUT : 0;
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}
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static int legacy_cond_signal(pthread_cond_t *cond)
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{
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EnterCriticalSection(&cond->lock_waiting);
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if(cond->waiting > 0)
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SetEvent(cond->events[SIGNAL]);
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LeaveCriticalSection(&cond->lock_waiting);
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return 0;
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}
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static int legacy_cond_broadcast(pthread_cond_t *cond)
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{
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EnterCriticalSection(&cond->lock_waiting);
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/*
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The mutex protect us from broadcasting if
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there isn't any thread waiting to open the
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block gate after this call has closed it.
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*/
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if(cond->waiting > 0)
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{
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/* Close block gate */
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ResetEvent(cond->broadcast_block_event);
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/* Open broadcast gate */
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SetEvent(cond->events[BROADCAST]);
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}
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LeaveCriticalSection(&cond->lock_waiting);
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return 0;
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}
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/*
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Posix API functions. Just choose between native and legacy implementation.
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*/
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int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
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{
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/*
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Once initialization is used here rather than in my_init(), to
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1) avoid my_init() pitfalls- undefined order in which initialization should
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run
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2) be potentially useful C++ (in static constructors that run before main())
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3) just to simplify the API.
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Also, the overhead of my_pthread_once is very small.
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*/
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static my_pthread_once_t once_control= MY_PTHREAD_ONCE_INIT;
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my_pthread_once(&once_control, check_native_cond_availability);
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if (have_native_conditions)
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{
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my_InitializeConditionVariable(&cond->native_cond);
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return 0;
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}
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else
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return legacy_cond_init(cond, attr);
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}
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int pthread_cond_destroy(pthread_cond_t *cond)
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{
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if (have_native_conditions)
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return 0; /* no destroy function */
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else
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return legacy_cond_destroy(cond);
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}
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int pthread_cond_broadcast(pthread_cond_t *cond)
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{
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if (have_native_conditions)
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{
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my_WakeAllConditionVariable(&cond->native_cond);
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return 0;
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}
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else
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return legacy_cond_broadcast(cond);
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}
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int pthread_cond_signal(pthread_cond_t *cond)
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{
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if (have_native_conditions)
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{
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my_WakeConditionVariable(&cond->native_cond);
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return 0;
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}
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else
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return legacy_cond_signal(cond);
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}
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int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
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const struct timespec *abstime)
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{
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if (have_native_conditions)
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{
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DWORD timeout= get_milliseconds(abstime);
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if (!my_SleepConditionVariableCS(&cond->native_cond, mutex, timeout))
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return ETIMEDOUT;
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return 0;
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}
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else
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return legacy_cond_timedwait(cond, mutex, abstime);
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}
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int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
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{
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return pthread_cond_timedwait(cond, mutex, NULL);
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}
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int pthread_attr_init(pthread_attr_t *connect_att)
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{
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connect_att->dwStackSize = 0;
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connect_att->dwCreatingFlag = 0;
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return 0;
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}
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int pthread_attr_setstacksize(pthread_attr_t *connect_att,DWORD stack)
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{
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connect_att->dwStackSize=stack;
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return 0;
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}
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int pthread_attr_destroy(pthread_attr_t *connect_att)
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{
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bzero((uchar*) connect_att,sizeof(*connect_att));
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return 0;
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}
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#endif /* __WIN__ */
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