threadpsx.cpp

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/////////////////////////////////////////////////////////////////////////////
// Name:        threadpsx.cpp
// Purpose:     wxThread (Posix) Implementation
// Author:      Original from Wolfram Gloger/Guilhem Lavaux
// Modified by: K. S. Sreeram (2002): POSIXified wxCondition, added wxSemaphore
// Created:     04/22/98
// RCS-ID:      $Id: threadpsx.cpp,v 1.83.2.1 2006/01/17 19:17:24 JS Exp $
// Copyright:   (c) Wolfram Gloger (1996, 1997)
//                  Guilhem Lavaux (1998)
//                  Vadim Zeitlin (1999-2002)
//                  Robert Roebling (1999)
//                  K. S. Sreeram (2002)
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ============================================================================
// declaration
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
    #pragma implementation "thread.h"
#endif

// for compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#if wxUSE_THREADS

#include "wx/thread.h"
#include "wx/module.h"
#include "wx/utils.h"
#include "wx/log.h"
#include "wx/intl.h"
#include "wx/dynarray.h"
#include "wx/timer.h"
#include "wx/stopwatch.h"

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
#include <time.h>
#ifdef HAVE_SCHED_H
    #include <sched.h>
#endif

#ifdef HAVE_THR_SETCONCURRENCY
    #include <thread.h>
#endif

// we use wxFFile under Linux in GetCPUCount()
#ifdef __LINUX__
    #include "wx/ffile.h"
    // For setpriority.
    #include <sys/time.h>
    #include <sys/resource.h>
#endif

#ifdef __VMS
    #define THR_ID(thr) ((long long)(thr)->GetId())
#else
    #define THR_ID(thr) ((long)(thr)->GetId())
#endif

// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------

// the possible states of the thread and transitions from them
enum wxThreadState
{
    STATE_NEW,          // didn't start execution yet (=> RUNNING)
    STATE_RUNNING,      // running (=> PAUSED or EXITED)
    STATE_PAUSED,       // suspended (=> RUNNING or EXITED)
    STATE_EXITED        // thread doesn't exist any more
};

// the exit value of a thread which has been cancelled
static const wxThread::ExitCode EXITCODE_CANCELLED = (wxThread::ExitCode)-1;

// trace mask for wxThread operations
#define TRACE_THREADS   _T("thread")

// you can get additional debugging messages for the semaphore operations
#define TRACE_SEMA      _T("semaphore")

// ----------------------------------------------------------------------------
// private functions
// ----------------------------------------------------------------------------

static void ScheduleThreadForDeletion();
static void DeleteThread(wxThread *This);

// ----------------------------------------------------------------------------
// private classes
// ----------------------------------------------------------------------------

// an (non owning) array of pointers to threads
WX_DEFINE_ARRAY_PTR(wxThread *, wxArrayThread);

// an entry for a thread we can wait for

// -----------------------------------------------------------------------------
// global data
// -----------------------------------------------------------------------------

// we keep the list of all threads created by the application to be able to
// terminate them on exit if there are some left - otherwise the process would
// be left in memory
static wxArrayThread gs_allThreads;

// the id of the main thread
static pthread_t gs_tidMain = (pthread_t)-1;

// the key for the pointer to the associated wxThread object
static pthread_key_t gs_keySelf;

// the number of threads which are being deleted - the program won't exit
// until there are any left
static size_t gs_nThreadsBeingDeleted = 0;

// a mutex to protect gs_nThreadsBeingDeleted
static wxMutex *gs_mutexDeleteThread = (wxMutex *)NULL;

// and a condition variable which will be signaled when all
// gs_nThreadsBeingDeleted will have been deleted
static wxCondition *gs_condAllDeleted = (wxCondition *)NULL;

// this mutex must be acquired before any call to a GUI function
// (it's not inside #if wxUSE_GUI because this file is compiled as part
// of wxBase)
static wxMutex *gs_mutexGui = NULL;

// when we wait for a thread to exit, we're blocking on a condition which the
// thread signals in its SignalExit() method -- but this condition can't be a
// member of the thread itself as a detached thread may delete itself at any
// moment and accessing the condition member of the thread after this would
// result in a disaster
//
// so instead we maintain a global list of the structs below for the threads
// we're interested in waiting on

// ============================================================================
// wxMutex implementation
// ============================================================================

// ----------------------------------------------------------------------------
// wxMutexInternal
// ----------------------------------------------------------------------------

// this is a simple wrapper around pthread_mutex_t which provides error
// checking
class wxMutexInternal
{
public:
    wxMutexInternal(wxMutexType mutexType);
    ~wxMutexInternal();

    wxMutexError Lock();
    wxMutexError TryLock();
    wxMutexError Unlock();

    bool IsOk() const { return m_isOk; }

private:
    pthread_mutex_t m_mutex;
    bool m_isOk;

    // wxConditionInternal uses our m_mutex
    friend class wxConditionInternal;
};

#ifdef HAVE_PTHREAD_MUTEXATTR_T
// on some systems pthread_mutexattr_settype() is not in the headers (but it is
// in the library, otherwise we wouldn't compile this code at all)
extern "C" int pthread_mutexattr_settype(pthread_mutexattr_t *, int);
#endif

wxMutexInternal::wxMutexInternal(wxMutexType mutexType)
{
    int err;
    switch ( mutexType )
    {
        case wxMUTEX_RECURSIVE:
            // support recursive locks like Win32, i.e. a thread can lock a
            // mutex which it had itself already locked
            //
            // unfortunately initialization of recursive mutexes is non
            // portable, so try several methods
#ifdef HAVE_PTHREAD_MUTEXATTR_T
            {
                pthread_mutexattr_t attr;
                pthread_mutexattr_init(&attr);
                pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);

                err = pthread_mutex_init(&m_mutex, &attr);
            }
#elif defined(HAVE_PTHREAD_RECURSIVE_MUTEX_INITIALIZER)
            // we can use this only as initializer so we have to assign it
            // first to a temp var - assigning directly to m_mutex wouldn't
            // even compile
            {
                pthread_mutex_t mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
                m_mutex = mutex;
            }
#else // no recursive mutexes
            err = EINVAL;
#endif // HAVE_PTHREAD_MUTEXATTR_T/...
            break;

        default:
            wxFAIL_MSG( _T("unknown mutex type") );
            // fall through

        case wxMUTEX_DEFAULT:
            err = pthread_mutex_init(&m_mutex, NULL);
            break;
    }

    m_isOk = err == 0;
    if ( !m_isOk )
    {
        wxLogApiError( wxT("pthread_mutex_init()"), err);
    }
}

wxMutexInternal::~wxMutexInternal()
{
    if ( m_isOk )
    {
        int err = pthread_mutex_destroy(&m_mutex);
        if ( err != 0 )
        {
            wxLogApiError( wxT("pthread_mutex_destroy()"), err);
        }
    }
}

wxMutexError wxMutexInternal::Lock()
{
    int err = pthread_mutex_lock(&m_mutex);
    switch ( err )
    {
        case EDEADLK:
            // only error checking mutexes return this value and so it's an
            // unexpected situation -- hence use assert, not wxLogDebug
            wxFAIL_MSG( _T("mutex deadlock prevented") );
            return wxMUTEX_DEAD_LOCK;

        case EINVAL:
            wxLogDebug(_T("pthread_mutex_lock(): mutex not initialized."));
            break;

        case 0:
            return wxMUTEX_NO_ERROR;

        default:
            wxLogApiError(_T("pthread_mutex_lock()"), err);
    }

    return wxMUTEX_MISC_ERROR;
}

wxMutexError wxMutexInternal::TryLock()
{
    int err = pthread_mutex_trylock(&m_mutex);
    switch ( err )
    {
        case EBUSY:
            // not an error: mutex is already locked, but we're prepared for
            // this
            return wxMUTEX_BUSY;

        case EINVAL:
            wxLogDebug(_T("pthread_mutex_trylock(): mutex not initialized."));
            break;

        case 0:
            return wxMUTEX_NO_ERROR;

        default:
            wxLogApiError(_T("pthread_mutex_trylock()"), err);
    }

    return wxMUTEX_MISC_ERROR;
}

wxMutexError wxMutexInternal::Unlock()
{
    int err = pthread_mutex_unlock(&m_mutex);
    switch ( err )
    {
        case EPERM:
            // we don't own the mutex
            return wxMUTEX_UNLOCKED;

        case EINVAL:
            wxLogDebug(_T("pthread_mutex_unlock(): mutex not initialized."));
            break;

        case 0:
            return wxMUTEX_NO_ERROR;

        default:
            wxLogApiError(_T("pthread_mutex_unlock()"), err);
    }

    return wxMUTEX_MISC_ERROR;
}

// ===========================================================================
// wxCondition implementation
// ===========================================================================

// ---------------------------------------------------------------------------
// wxConditionInternal
// ---------------------------------------------------------------------------

// this is a wrapper around pthread_cond_t associated with a wxMutex (and hence
// with a pthread_mutex_t)
class wxConditionInternal
{
public:
    wxConditionInternal(wxMutex& mutex);
    ~wxConditionInternal();

    bool IsOk() const { return m_isOk && m_mutex.IsOk(); }

    wxCondError Wait();
    wxCondError WaitTimeout(unsigned long milliseconds);

    wxCondError Signal();
    wxCondError Broadcast();

private:
    // get the POSIX mutex associated with us
    pthread_mutex_t *GetPMutex() const { return &m_mutex.m_internal->m_mutex; }

    wxMutex& m_mutex;
    pthread_cond_t m_cond;

    bool m_isOk;
};

wxConditionInternal::wxConditionInternal(wxMutex& mutex)
                   : m_mutex(mutex)
{
    int err = pthread_cond_init(&m_cond, NULL /* default attributes */);

    m_isOk = err == 0;

    if ( !m_isOk )
    {
        wxLogApiError(_T("pthread_cond_init()"), err);
    }
}

wxConditionInternal::~wxConditionInternal()
{
    if ( m_isOk )
    {
        int err = pthread_cond_destroy(&m_cond);
        if ( err != 0 )
        {
            wxLogApiError(_T("pthread_cond_destroy()"), err);
        }
    }
}

wxCondError wxConditionInternal::Wait()
{
    int err = pthread_cond_wait(&m_cond, GetPMutex());
    if ( err != 0 )
    {
        wxLogApiError(_T("pthread_cond_wait()"), err);

        return wxCOND_MISC_ERROR;
    }

    return wxCOND_NO_ERROR;
}

wxCondError wxConditionInternal::WaitTimeout(unsigned long milliseconds)
{
    wxLongLong curtime = wxGetLocalTimeMillis();
    curtime += milliseconds;
    wxLongLong temp = curtime / 1000;
    int sec = temp.GetLo();
    temp *= 1000;
    temp = curtime - temp;
    int millis = temp.GetLo();

    timespec tspec;

    tspec.tv_sec = sec;
    tspec.tv_nsec = millis * 1000L * 1000L;

    int err = pthread_cond_timedwait( &m_cond, GetPMutex(), &tspec );
    switch ( err )
    {
        case ETIMEDOUT:
            return wxCOND_TIMEOUT;

        case 0:
            return wxCOND_NO_ERROR;

        default:
            wxLogApiError(_T("pthread_cond_timedwait()"), err);
    }

    return wxCOND_MISC_ERROR;
}

wxCondError wxConditionInternal::Signal()
{
    int err = pthread_cond_signal(&m_cond);
    if ( err != 0 )
    {
        wxLogApiError(_T("pthread_cond_signal()"), err);

        return wxCOND_MISC_ERROR;
    }

    return wxCOND_NO_ERROR;
}

wxCondError wxConditionInternal::Broadcast()
{