windows/SysSemaphore.hpp

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/* REXX Windows Support                                                      */
/*                                                                           */
/* Semaphore support for Windows systems                                     */
/*                                                                           */
/*****************************************************************************/
 
#ifndef Included_SysSemaphore
#define Included_SysSemaphore
 
#include "rexx.h"
#include "SysDebug.hpp"
#include "Utilities.hpp"
 
#include <stdlib.h>
#include <stdio.h>
 
inline void waitHandle(HANDLE s);
 
class SysSemaphore {
public:
     SysSemaphore(const char *variable) : semVariable(variable), sem(0) { ; }
     SysSemaphore(const char *variable, bool);
     ~SysSemaphore() { ; }
     void create();
     inline void open() { ; }
     void close();
     void post() { SetEvent(sem); };
     inline void wait(const char *ds, int di)
     {
#if CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysSemaphore)%s.wait : before waitHandle(0x%x) from %s (0x%x)\n", semVariable, sem, ds, di);
#endif
         waitHandle(sem);
#if CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysSemaphore)%s.wait : after waitHandle(0x%x) from %s (0x%x)\n", semVariable, sem, ds, di);
#endif
     }
 
     inline bool wait(const char *ds, int di, uint32_t timeout)
     {
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysSemaphore)%s.wait : before WaitForSingleObject(0x%x, timemout) from %s (0x%x)\n", semVariable, sem, timeout, ds, di);
#endif
         bool result = WaitForSingleObject(sem, timeout) != WAIT_TIMEOUT;
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysSemaphore)%s.wait : after WaitForSingleObject(0x%x, timemout) from %s (0x%x)\n", semVariable, sem, timeout, ds, di);
#endif
         return result;
     }
 
     inline void reset() { ResetEvent(sem); }
     inline bool posted() { return WaitForSingleObject(sem, 0) != 0; }
 
     inline void setSemVariable(const char *variable) { semVariable = variable; } // See RexxActivity::RexxActivity, must reassign, so public setter needed.
 
     static inline bool allocTlsIndex()
     {
         tlsNoMessageLoopIndex = TlsAlloc();
         usingTls = (tlsNoMessageLoopIndex != TLS_OUT_OF_INDEXES);
         return usingTls;
     }
     static inline void deallocTlsIndex()
     {
         TlsFree(tlsNoMessageLoopIndex);
         usingTls = false;
     }
 
     static inline void setNoMessageLoop() { TlsSetValue(tlsNoMessageLoopIndex, (LPVOID)1); }
     static inline bool noMessageLoop() { return usingTls && ((DWORD_PTR)TlsGetValue(tlsNoMessageLoopIndex) == 1); }
 
protected:
     const char *semVariable;
     HANDLE sem;
 
private:
     static bool usingTls;
     static DWORD tlsNoMessageLoopIndex;
 
};
 
 
class SysMutex {
public:
     SysMutex(const char *variable) : mutexVariable(variable), mutexMutex(0) { }
     SysMutex(const char *, bool);
     ~SysMutex() { ; }
     void create();
     void close();
     inline void request(const char *ds, int di)
     {
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysMutex)%s.request : before waitHandle(0x%x) from %s (0x%x)\n", mutexVariable, mutexMutex, ds, di);
#endif
         waitHandle(mutexMutex);
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysMutex)%s.request : after waitHandle(0x%x) from %s (0x%x)\n", mutexVariable, mutexMutex, ds, di);
#endif
     }
 
     inline void release(const char *ds, int di)
     {
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysMutex)%s.release : before ReleaseMutex(0x%x) from %s (0x%x)\n", mutexVariable, mutexMutex, ds, di);
#endif
         ReleaseMutex(mutexMutex);
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysMutex)%s.release : after ReleaseMutex(0x%x) from %s (0x%x)\n", mutexVariable, mutexMutex, ds, di);
#endif
     }
 
     inline bool requestImmediate(const char *ds, int di)
     {
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysMutex)%s.requestImmediate : before WaitForSingleObject(0x%x) from %s (0x%x)\n", mutexVariable, mutexMutex, ds, di);
#endif
         bool result = WaitForSingleObject(mutexMutex, 0) != WAIT_TIMEOUT;
#ifdef CONCURRENCY_DEBUG
         if (Utilities::traceConcurrency()) dbgprintf(CONCURRENCY_TRACE "...... ... ", Utilities::currentThreadId(), NULL, NULL, 0, ' ');
         dbgprintf("(SysMutex)%s.requestImmediate : after WaitForSingleObject(0x%x) from %s (0x%x)\n", mutexVariable, mutexMutex, ds, di);
#endif
         return result;
     }
 
protected:
     const char *mutexVariable;
     HANDLE mutexMutex;      // the actual mutex
};
 
 
/**
 *  Wait for a synchronization object to be in the signaled state.
 *
 *  Any thread that creates windows must process messages.  A thread that
 *  calls WaitForSingelObject with an infinite timeout risks deadlocking the
 *  system.  MS's solution for this is to use MsgWaitForMultipleObjects to
 *  wait on the object, or a new message arriving in the message queue. Some
 *  threads create windows indirectly, an example is COM with CoInitialize.
 *  Since we can't know if the current thread has a message queue that needs
 *  processing, we use MsgWaitForMultipleObjects.
 *
 *  However, with the introduction of the C++ native API in ooRexx 4.0.0, it
 *  became possible for external native libraries to attach a thread with an
 *  active window procedure to the interpreter. If a wait is done on that
 *  thread, here in waitHandle(), PeekMessage() causes non-queued messages to be
 *  dispatched, and the window procedure is reentered. This can cause the Rexx
 *  program to hang. In addition, in the one known extension where this problem
 *  happens, ooDialog, the messages need to be passed to the dialog manager
 *  rather than dispatched directly to the window.
 *
 *  For this special case, the thread can explicity ask, through
 *  RexxSetProcessMessages(), that messages are *not* processed during this
 *  wait. Thread local storage is used to keep track of a flag signalling this
 *  case on a per-thread basis.
 *
 *  Note that MsgWaitForMultipleObjects only returns if a new message is
 *  placed in the queue.  PeekMessage alters the state of all messages in
 *  the queue so that they are no longer 'new.'  Once PeekMessage is called,
 *  all the messages on the queue need to be processed.
 */
inline void waitHandle(HANDLE s)
{
    // If already signaled, return.
    if ( WaitForSingleObject(s, 0) == WAIT_OBJECT_0 )
    {
        return;
    }
 
    // If no message loop is flagged, then use WaitForSingleobject()
    if ( SysSemaphore::noMessageLoop() )
    {
        WaitForSingleObject(s, INFINITE);
        return;
    }
 
    MSG msg = {0};
 
    do
    {
        while ( PeekMessage(&msg, NULL, 0, 0, PM_REMOVE) )
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
 
            // Check to see if signaled.
            if ( WaitForSingleObject(s, 0) == WAIT_OBJECT_0 )
            {
                return;
            }
        }
    } while ( MsgWaitForMultipleObjects(1, &s, FALSE, INFINITE, QS_ALLINPUT) == WAIT_OBJECT_0 + 1 );
}
 
 
#endif