/////////////////////////////////////////////////////////////////////////////
-// Name: thread.cpp
+// Name: src/msw/thread.cpp
// Purpose: wxThread Implementation
// Author: Original from Wolfram Gloger/Guilhem Lavaux
// Modified by: Vadim Zeitlin to make it work :-)
// Created: 04/22/98
// RCS-ID: $Id$
-// Copyright: (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998),
-// Vadim Zeitlin (1999)
+// Copyright: (c) Wolfram Gloger (1996, 1997), Guilhem Lavaux (1998);
+// Vadim Zeitlin (1999-2002)
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-#ifdef __GNUG__
- #pragma implementation "thread.h"
-#endif
-
// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
#pragma hdrstop
#endif
+#if wxUSE_THREADS
+
+#include "wx/thread.h"
+
#ifndef WX_PRECOMP
-# include "wx/wx.h"
+ #include "wx/intl.h"
+ #include "wx/app.h"
+ #include "wx/module.h"
#endif
-#if wxUSE_THREADS
+#include "wx/apptrait.h"
+#include "wx/scopeguard.h"
#include "wx/msw/private.h"
+#include "wx/msw/missing.h"
+#include "wx/msw/seh.h"
-#include "wx/module.h"
-#include "wx/thread.h"
+#include "wx/except.h"
-#ifdef Yield
-# undef Yield
-#endif
+#include "wx/dynlib.h"
// must have this symbol defined to get _beginthread/_endthread declarations
#ifndef _MT
(defined(__GNUG__) && defined(__MSVCRT__)) || \
defined(__WATCOMC__)
+#ifndef __WXWINCE__
#undef wxUSE_BEGIN_THREAD
#define wxUSE_BEGIN_THREAD
#endif
+#endif
+
#ifdef wxUSE_BEGIN_THREAD
// this is where _beginthreadex() is declared
#include <process.h>
- // the return type of the thread function entry point
+ // the return type of the thread function entry point: notice that this
+ // type can't hold a pointer under Win64
typedef unsigned THREAD_RETVAL;
// the calling convention of the thread function entry point
#define THREAD_CALLCONV WINAPI
#endif
+static const THREAD_RETVAL THREAD_ERROR_EXIT = (THREAD_RETVAL)-1;
+
// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------
// id of the main thread - the one which can call GUI functions without first
// calling wxMutexGuiEnter()
-static DWORD gs_idMainThread = 0;
+wxThreadIdType wxThread::ms_idMainThread = 0;
-// if it's FALSE, some secondary thread is holding the GUI lock
-static bool gs_bGuiOwnedByMainThread = TRUE;
+// if it's false, some secondary thread is holding the GUI lock
+static bool gs_bGuiOwnedByMainThread = true;
// critical section which controls access to all GUI functions: any secondary
// thread (i.e. except the main one) must enter this crit section before doing
// critical section which protects gs_nWaitingForGui variable
static wxCriticalSection *gs_critsectWaitingForGui = NULL;
+// critical section which serializes WinThreadStart() and WaitForTerminate()
+// (this is a potential bottleneck, we use a single crit sect for all threads
+// in the system, but normally time spent inside it should be quite short)
+static wxCriticalSection *gs_critsectThreadDelete = NULL;
+
// number of threads waiting for GUI in wxMutexGuiEnter()
static size_t gs_nWaitingForGui = 0;
// are we waiting for a thread termination?
-static bool gs_waitingForThread = FALSE;
+static bool gs_waitingForThread = false;
// ============================================================================
-// Windows implementation of thread classes
+// Windows implementation of thread and related classes
// ============================================================================
// ----------------------------------------------------------------------------
-// wxMutex implementation
+// wxCriticalSection
+// ----------------------------------------------------------------------------
+
+wxCriticalSection::wxCriticalSection( wxCriticalSectionType WXUNUSED(critSecType) )
+{
+ wxCOMPILE_TIME_ASSERT( sizeof(CRITICAL_SECTION) <= sizeof(wxCritSectBuffer),
+ wxCriticalSectionBufferTooSmall );
+
+ ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+wxCriticalSection::~wxCriticalSection()
+{
+ ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+void wxCriticalSection::Enter()
+{
+ ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+bool wxCriticalSection::TryEnter()
+{
+#if wxUSE_DYNLIB_CLASS
+ typedef BOOL
+ (WINAPI *TryEnterCriticalSection_t)(LPCRITICAL_SECTION lpCriticalSection);
+
+ static TryEnterCriticalSection_t
+ pfnTryEnterCriticalSection = (TryEnterCriticalSection_t)
+ wxDynamicLibrary(wxT("kernel32.dll")).
+ GetSymbol(wxT("TryEnterCriticalSection"));
+
+ return pfnTryEnterCriticalSection
+ ? (*pfnTryEnterCriticalSection)((CRITICAL_SECTION *)m_buffer) != 0
+ : false;
+#else
+ return false;
+#endif
+}
+
+void wxCriticalSection::Leave()
+{
+ ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+// ----------------------------------------------------------------------------
+// wxMutex
// ----------------------------------------------------------------------------
class wxMutexInternal
{
public:
- wxMutexInternal()
- {
- m_mutex = ::CreateMutex(NULL, FALSE, NULL);
- if ( !m_mutex )
- {
- wxLogSysError(_("Can not create mutex"));
- }
- }
+ wxMutexInternal(wxMutexType mutexType);
+ ~wxMutexInternal();
- ~wxMutexInternal() { if ( m_mutex ) CloseHandle(m_mutex); }
+ bool IsOk() const { return m_mutex != NULL; }
+
+ wxMutexError Lock() { return LockTimeout(INFINITE); }
+ wxMutexError Lock(unsigned long ms) { return LockTimeout(ms); }
+ wxMutexError TryLock();
+ wxMutexError Unlock();
+
+private:
+ wxMutexError LockTimeout(DWORD milliseconds);
-public:
HANDLE m_mutex;
+
+ unsigned long m_owningThread;
+ wxMutexType m_type;
+
+ wxDECLARE_NO_COPY_CLASS(wxMutexInternal);
};
-wxMutex::wxMutex()
+// all mutexes are recursive under Win32 so we don't use mutexType
+wxMutexInternal::wxMutexInternal(wxMutexType mutexType)
{
- m_internal = new wxMutexInternal;
+ // create a nameless (hence intra process and always private) mutex
+ m_mutex = ::CreateMutex
+ (
+ NULL, // default secutiry attributes
+ FALSE, // not initially locked
+ NULL // no name
+ );
+
+ m_type = mutexType;
+ m_owningThread = 0;
+
+ if ( !m_mutex )
+ {
+ wxLogLastError(wxT("CreateMutex()"));
+ }
- m_locked = 0;
}
-wxMutex::~wxMutex()
+wxMutexInternal::~wxMutexInternal()
{
- if ( m_locked > 0 )
+ if ( m_mutex )
{
- wxLogDebug(_T("Warning: freeing a locked mutex (%d locks)."), m_locked);
+ if ( !::CloseHandle(m_mutex) )
+ {
+ wxLogLastError(wxT("CloseHandle(mutex)"));
+ }
}
+}
- delete m_internal;
+wxMutexError wxMutexInternal::TryLock()
+{
+ const wxMutexError rc = LockTimeout(0);
+
+ // we have a special return code for timeout in this case
+ return rc == wxMUTEX_TIMEOUT ? wxMUTEX_BUSY : rc;
}
-wxMutexError wxMutex::Lock()
+wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
{
- DWORD ret;
+ if (m_type == wxMUTEX_DEFAULT)
+ {
+ // Don't allow recursive
+ if (m_owningThread != 0)
+ {
+ if (m_owningThread == wxThread::GetCurrentId())
+ return wxMUTEX_DEAD_LOCK;
+ }
+ }
- ret = WaitForSingleObject(m_internal->m_mutex, INFINITE);
- switch ( ret )
+ DWORD rc = ::WaitForSingleObject(m_mutex, milliseconds);
+ switch ( rc )
{
case WAIT_ABANDONED:
- return wxMUTEX_BUSY;
+ // the previous caller died without releasing the mutex, so even
+ // though we did get it, log a message about this
+ wxLogDebug(wxT("WaitForSingleObject() returned WAIT_ABANDONED"));
+ // fall through
case WAIT_OBJECT_0:
// ok
break;
- case WAIT_FAILED:
- wxLogSysError(_("Couldn't acquire a mutex lock"));
- return wxMUTEX_MISC_ERROR;
-
case WAIT_TIMEOUT:
+ return wxMUTEX_TIMEOUT;
+
default:
wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
- }
-
- m_locked++;
- return wxMUTEX_NO_ERROR;
-}
+ // fall through
-wxMutexError wxMutex::TryLock()
-{
- DWORD ret;
+ case WAIT_FAILED:
+ wxLogLastError(wxT("WaitForSingleObject(mutex)"));
+ return wxMUTEX_MISC_ERROR;
+ }
- ret = WaitForSingleObject(m_internal->m_mutex, 0);
- if (ret == WAIT_TIMEOUT || ret == WAIT_ABANDONED)
- return wxMUTEX_BUSY;
+ if (m_type == wxMUTEX_DEFAULT)
+ {
+ // required for checking recursiveness
+ m_owningThread = wxThread::GetCurrentId();
+ }
- m_locked++;
return wxMUTEX_NO_ERROR;
}
-wxMutexError wxMutex::Unlock()
+wxMutexError wxMutexInternal::Unlock()
{
- if (m_locked > 0)
- m_locked--;
+ // required for checking recursiveness
+ m_owningThread = 0;
- BOOL ret = ReleaseMutex(m_internal->m_mutex);
- if ( ret == 0 )
+ if ( !::ReleaseMutex(m_mutex) )
{
- wxLogSysError(_("Couldn't release a mutex"));
+ wxLogLastError(wxT("ReleaseMutex()"));
+
return wxMUTEX_MISC_ERROR;
}
return wxMUTEX_NO_ERROR;
}
-// ----------------------------------------------------------------------------
-// wxCondition implementation
-// ----------------------------------------------------------------------------
+// --------------------------------------------------------------------------
+// wxSemaphore
+// --------------------------------------------------------------------------
-class wxConditionInternal
+// a trivial wrapper around Win32 semaphore
+class wxSemaphoreInternal
{
public:
- wxConditionInternal()
+ wxSemaphoreInternal(int initialcount, int maxcount);
+ ~wxSemaphoreInternal();
+
+ bool IsOk() const { return m_semaphore != NULL; }
+
+ wxSemaError Wait() { return WaitTimeout(INFINITE); }
+
+ wxSemaError TryWait()
{
- m_hEvent = ::CreateEvent(
- NULL, // default secutiry
- FALSE, // not manual reset
- FALSE, // nonsignaled initially
- NULL // nameless event
- );
- if ( !m_hEvent )
- {
- wxLogSysError(_("Can not create event object."));
- }
+ wxSemaError rc = WaitTimeout(0);
+ if ( rc == wxSEMA_TIMEOUT )
+ rc = wxSEMA_BUSY;
- // nobody waits for us yet
- m_nWaiters = 0;
+ return rc;
}
- bool Wait(DWORD timeout)
- {
- // as m_nWaiters variable is accessed from multiple waiting threads
- // (and possibly from the broadcasting thread), we need to change its
- // value atomically
- ::InterlockedIncrement(&m_nWaiters);
+ wxSemaError WaitTimeout(unsigned long milliseconds);
- // FIXME this should be MsgWaitForMultipleObjects() as we want to keep
- // processing Windows messages while waiting (or don't we?)
- DWORD rc = ::WaitForSingleObject(m_hEvent, timeout);
+ wxSemaError Post();
- ::InterlockedDecrement(&m_nWaiters);
+private:
+ HANDLE m_semaphore;
- return rc != WAIT_TIMEOUT;
- }
+ wxDECLARE_NO_COPY_CLASS(wxSemaphoreInternal);
+};
- void Signal()
+wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
+{
+#if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
+ if ( maxcount == 0 )
{
- // set the event to signaled: if a thread is already waiting on it, it
- // will be woken up, otherwise the event will remain in the signaled
- // state until someone waits on it. In any case, the system will return
- // it to a non signalled state afterwards. If multiple threads are
- // waiting, only one will be woken up.
- if ( !::SetEvent(m_hEvent) )
- {
- wxLogLastError(wxT("SetEvent"));
- }
+ // make it practically infinite
+ maxcount = INT_MAX;
}
- void Broadcast()
+ m_semaphore = ::CreateSemaphore
+ (
+ NULL, // default security attributes
+ initialcount,
+ maxcount,
+ NULL // no name
+ );
+#endif
+ if ( !m_semaphore )
{
- // we need to save the original value as m_nWaiters is goign to be
- // decreased by the signalled thread resulting in the loop being
- // executed less times than needed
- LONG nWaiters = m_nWaiters;
-
- // this works because all these threads are already waiting and so each
- // SetEvent() inside Signal() is really a PulseEvent() because the
- // event state is immediately returned to non-signaled
- for ( LONG n = 0; n < nWaiters; n++ )
- {
- Signal();
- }
+ wxLogLastError(wxT("CreateSemaphore()"));
}
+}
- ~wxConditionInternal()
+wxSemaphoreInternal::~wxSemaphoreInternal()
+{
+ if ( m_semaphore )
{
- if ( m_hEvent )
+ if ( !::CloseHandle(m_semaphore) )
{
- if ( !::CloseHandle(m_hEvent) )
- {
- wxLogLastError(wxT("CloseHandle(event)"));
- }
+ wxLogLastError(wxT("CloseHandle(semaphore)"));
}
}
-
-private:
- // the Win32 synchronization object corresponding to this event
- HANDLE m_hEvent;
-
- // number of threads waiting for this condition
- LONG m_nWaiters;
-};
-
-wxCondition::wxCondition()
-{
- m_internal = new wxConditionInternal;
}
-wxCondition::~wxCondition()
+wxSemaError wxSemaphoreInternal::WaitTimeout(unsigned long milliseconds)
{
- delete m_internal;
-}
-
-void wxCondition::Wait()
-{
- (void)m_internal->Wait(INFINITE);
-}
+ DWORD rc = ::WaitForSingleObject( m_semaphore, milliseconds );
-bool wxCondition::Wait(unsigned long sec,
- unsigned long nsec)
-{
- return m_internal->Wait(sec*1000 + nsec/1000000);
-}
-
-void wxCondition::Signal()
-{
- m_internal->Signal();
-}
-
-void wxCondition::Broadcast()
-{
- m_internal->Broadcast();
-}
-
-// ----------------------------------------------------------------------------
-// wxCriticalSection implementation
-// ----------------------------------------------------------------------------
+ switch ( rc )
+ {
+ case WAIT_OBJECT_0:
+ return wxSEMA_NO_ERROR;
-wxCriticalSection::wxCriticalSection()
-{
-#ifdef __WXDEBUG__
- // Done this way to stop warnings during compilation about statement
- // always being false
- int csSize = sizeof(CRITICAL_SECTION);
- int bSize = sizeof(m_buffer);
- wxASSERT_MSG( csSize <= bSize,
- _T("must increase buffer size in wx/thread.h") );
-#endif
+ case WAIT_TIMEOUT:
+ return wxSEMA_TIMEOUT;
- ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
-}
+ default:
+ wxLogLastError(wxT("WaitForSingleObject(semaphore)"));
+ }
-wxCriticalSection::~wxCriticalSection()
-{
- ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
+ return wxSEMA_MISC_ERROR;
}
-void wxCriticalSection::Enter()
+wxSemaError wxSemaphoreInternal::Post()
{
- ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
-}
+#if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
+ if ( !::ReleaseSemaphore(m_semaphore, 1, NULL /* ptr to previous count */) )
+ {
+ if ( GetLastError() == ERROR_TOO_MANY_POSTS )
+ {
+ return wxSEMA_OVERFLOW;
+ }
+ else
+ {
+ wxLogLastError(wxT("ReleaseSemaphore"));
+ return wxSEMA_MISC_ERROR;
+ }
+ }
-void wxCriticalSection::Leave()
-{
- ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
+ return wxSEMA_NO_ERROR;
+#else
+ return wxSEMA_MISC_ERROR;
+#endif
}
// ----------------------------------------------------------------------------
class wxThreadInternal
{
public:
- wxThreadInternal()
+ wxThreadInternal(wxThread *thread)
{
+ m_thread = thread;
m_hThread = 0;
m_state = STATE_NEW;
- m_priority = WXTHREAD_DEFAULT_PRIORITY;
+ m_priority = wxPRIORITY_DEFAULT;
+ m_nRef = 1;
}
~wxThreadInternal()
}
// create a new (suspended) thread (for the given thread object)
- bool Create(wxThread *thread);
+ bool Create(wxThread *thread, unsigned int stackSize);
+
+ // wait for the thread to terminate, either by itself, or by asking it
+ // (politely, this is not Kill()!) to do it
+ wxThreadError WaitForTerminate(wxCriticalSection& cs,
+ wxThread::ExitCode *pRc,
+ wxThreadWait waitMode,
+ wxThread *threadToDelete = NULL);
+
+ // kill the thread unconditionally
+ wxThreadError Kill();
// suspend/resume/terminate
bool Suspend();
HANDLE GetHandle() const { return m_hThread; }
DWORD GetId() const { return m_tid; }
- // thread function
+ // the thread function forwarding to DoThreadStart
static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
+ // really start the thread (if it's not already dead)
+ static THREAD_RETVAL DoThreadStart(wxThread *thread);
+
+ // call OnExit() on the thread
+ static void DoThreadOnExit(wxThread *thread);
+
+
+ void KeepAlive()
+ {
+ if ( m_thread->IsDetached() )
+ ::InterlockedIncrement(&m_nRef);
+ }
+
+ void LetDie()
+ {
+ if ( m_thread->IsDetached() && !::InterlockedDecrement(&m_nRef) )
+ delete m_thread;
+ }
+
private:
+ // the thread we're associated with
+ wxThread *m_thread;
+
HANDLE m_hThread; // handle of the thread
wxThreadState m_state; // state, see wxThreadState enum
unsigned int m_priority; // thread priority in "wx" units
DWORD m_tid; // thread id
+
+ // number of threads which need this thread to remain alive, when the count
+ // reaches 0 we kill the owning wxThread -- and die ourselves with it
+ LONG m_nRef;
+
+ wxDECLARE_NO_COPY_CLASS(wxThreadInternal);
};
-THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
+// small class which keeps a thread alive during its lifetime
+class wxThreadKeepAlive
{
- THREAD_RETVAL rc;
- bool wasCancelled;
+public:
+ wxThreadKeepAlive(wxThreadInternal& thrImpl) : m_thrImpl(thrImpl)
+ { m_thrImpl.KeepAlive(); }
+ ~wxThreadKeepAlive()
+ { m_thrImpl.LetDie(); }
- // first of all, check whether we hadn't been cancelled already and don't
- // start the user code at all then
- wxThread *thread = (wxThread *)param;
- if ( thread->m_internal->GetState() == STATE_EXITED )
+private:
+ wxThreadInternal& m_thrImpl;
+};
+
+/* static */
+void wxThreadInternal::DoThreadOnExit(wxThread *thread)
+{
+ wxTRY
{
- rc = (THREAD_RETVAL)-1;
- wasCancelled = TRUE;
+ thread->OnExit();
}
- else // do run thread
+ wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
+}
+
+/* static */
+THREAD_RETVAL wxThreadInternal::DoThreadStart(wxThread *thread)
+{
+ wxON_BLOCK_EXIT1(DoThreadOnExit, thread);
+
+ THREAD_RETVAL rc = THREAD_ERROR_EXIT;
+
+ wxTRY
{
// store the thread object in the TLS
if ( !::TlsSetValue(gs_tlsThisThread, thread) )
{
- wxLogSysError(_("Can not start thread: error writing TLS."));
+ wxLogSysError(_("Cannot start thread: error writing TLS."));
- return (DWORD)-1;
+ return THREAD_ERROR_EXIT;
}
- rc = (THREAD_RETVAL)thread->Entry();
+ rc = wxPtrToUInt(thread->Entry());
+ }
+ wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
- // enter m_critsect before changing the thread state
- thread->m_critsect.Enter();
- wasCancelled = thread->m_internal->GetState() == STATE_CANCELED;
- thread->m_internal->SetState(STATE_EXITED);
- thread->m_critsect.Leave();
+ return rc;
+}
+
+/* static */
+THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
+{
+ THREAD_RETVAL rc = THREAD_ERROR_EXIT;
+
+ wxThread * const thread = (wxThread *)param;
+
+ // each thread has its own SEH translator so install our own a.s.a.p.
+ DisableAutomaticSETranslator();
+
+ // NB: Notice that we can't use wxCriticalSectionLocker in this function as
+ // we use SEH and it's incompatible with C++ object dtors.
+
+ // first of all, check whether we hadn't been cancelled already and don't
+ // start the user code at all then
+ thread->m_critsect.Enter();
+ const bool hasExited = thread->m_internal->GetState() == STATE_EXITED;
+ thread->m_critsect.Leave();
+
+ // run the thread function itself inside a SEH try/except block
+ wxSEH_TRY
+ {
+ if ( hasExited )
+ DoThreadOnExit(thread);
+ else
+ rc = DoThreadStart(thread);
}
+ wxSEH_HANDLE(THREAD_ERROR_EXIT)
- thread->OnExit();
- // if the thread was cancelled (from Delete()), then its handle is still
- // needed there
- if ( thread->IsDetached() && !wasCancelled )
+ // save IsDetached because thread object can be deleted by joinable
+ // threads after state is changed to STATE_EXITED.
+ const bool isDetached = thread->IsDetached();
+ if ( !hasExited )
{
- // auto delete
- delete thread;
+ thread->m_critsect.Enter();
+ thread->m_internal->SetState(STATE_EXITED);
+ thread->m_critsect.Leave();
}
- //else: the joinable threads handle will be closed when Wait() is done
+
+ // the thread may delete itself now if it wants, we don't need it any more
+ if ( isDetached )
+ thread->m_internal->LetDie();
return rc;
}
{
m_priority = priority;
- // translate wxWindows priority to the Windows one
+ // translate wxWidgets priority to the Windows one
int win_priority;
if (m_priority <= 20)
win_priority = THREAD_PRIORITY_LOWEST;
}
}
-bool wxThreadInternal::Create(wxThread *thread)
+bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
{
+ wxASSERT_MSG( m_state == STATE_NEW && !m_hThread,
+ wxT("Create()ing thread twice?") );
+
// for compilers which have it, we should use C RTL function for thread
// creation instead of Win32 API one because otherwise we will have memory
// leaks if the thread uses C RTL (and most threads do)
#ifdef wxUSE_BEGIN_THREAD
+
+ // Watcom is reported to not like 0 stack size (which means "use default"
+ // for the other compilers and is also the default value for stackSize)
+#ifdef __WATCOMC__
+ if ( !stackSize )
+ stackSize = 10240;
+#endif // __WATCOMC__
+
m_hThread = (HANDLE)_beginthreadex
(
- NULL, // default security
-#ifdef __WATCOMC__
- 10240, // stack size can't be NULL in Watcom
-#else
- 0, // default stack size
-#endif
- wxThreadInternal::WinThreadStart, // entry point
- thread,
- CREATE_SUSPENDED,
- (unsigned int *)&m_tid
+ NULL, // default security
+ stackSize,
+ wxThreadInternal::WinThreadStart, // entry point
+ thread,
+ CREATE_SUSPENDED,
+ (unsigned int *)&m_tid
);
#else // compiler doesn't have _beginthreadex
m_hThread = ::CreateThread
(
NULL, // default security
- 0, // default stack size
+ stackSize, // stack size
wxThreadInternal::WinThreadStart, // thread entry point
(LPVOID)thread, // parameter
CREATE_SUSPENDED, // flags
{
wxLogSysError(_("Can't create thread"));
- return FALSE;
+ return false;
}
- if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
+ if ( m_priority != wxPRIORITY_DEFAULT )
{
SetPriority(m_priority);
}
- return TRUE;
+ return true;
+}
+
+wxThreadError wxThreadInternal::Kill()
+{
+ m_thread->OnKill();
+
+ if ( !::TerminateThread(m_hThread, THREAD_ERROR_EXIT) )
+ {
+ wxLogSysError(_("Couldn't terminate thread"));
+
+ return wxTHREAD_MISC_ERROR;
+ }
+
+ Free();
+
+ return wxTHREAD_NO_ERROR;
+}
+
+wxThreadError
+wxThreadInternal::WaitForTerminate(wxCriticalSection& cs,
+ wxThread::ExitCode *pRc,
+ wxThreadWait waitMode,
+ wxThread *threadToDelete)
+{
+ // prevent the thread C++ object from disappearing as long as we are using
+ // it here
+ wxThreadKeepAlive keepAlive(*this);
+
+
+ // we may either wait passively for the thread to terminate (when called
+ // from Wait()) or ask it to terminate (when called from Delete())
+ bool shouldDelete = threadToDelete != NULL;
+
+ DWORD rc = 0;
+
+ // we might need to resume the thread if it's currently stopped
+ bool shouldResume = false;
+
+ // as Delete() (which calls us) is always safe to call we need to consider
+ // all possible states
+ {
+ wxCriticalSectionLocker lock(cs);
+
+ if ( m_state == STATE_NEW )
+ {
+ if ( shouldDelete )
+ {
+ // WinThreadStart() will see it and terminate immediately, no
+ // need to cancel the thread -- but we still need to resume it
+ // to let it run
+ m_state = STATE_EXITED;
+
+ // we must call Resume() as the thread hasn't been initially
+ // resumed yet (and as Resume() it knows about STATE_EXITED
+ // special case, it won't touch it and WinThreadStart() will
+ // just exit immediately)
+ shouldResume = true;
+ shouldDelete = false;
+ }
+ //else: shouldResume is correctly set to false here, wait until
+ // someone else runs the thread and it finishes
+ }
+ else // running, paused, cancelled or even exited
+ {
+ shouldResume = m_state == STATE_PAUSED;
+ }
+ }
+
+ // resume the thread if it is paused
+ if ( shouldResume )
+ Resume();
+
+ // ask the thread to terminate
+ if ( shouldDelete )
+ {
+ wxCriticalSectionLocker lock(cs);
+
+ Cancel();
+ }
+
+ if ( threadToDelete )
+ threadToDelete->OnDelete();
+
+ // now wait for thread to finish
+ if ( wxThread::IsMain() )
+ {
+ // set flag for wxIsWaitingForThread()
+ gs_waitingForThread = true;
+ }
+
+ // we can't just wait for the thread to terminate because it might be
+ // calling some GUI functions and so it will never terminate before we
+ // process the Windows messages that result from these functions
+ // (note that even in console applications we might have to process
+ // messages if we use wxExecute() or timers or ...)
+ DWORD result wxDUMMY_INITIALIZE(0);
+ do
+ {
+ if ( wxThread::IsMain() )
+ {
+ // give the thread we're waiting for chance to do the GUI call
+ // it might be in
+ if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
+ {
+ wxMutexGuiLeave();
+ }
+ }
+
+ wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits() : NULL;
+ if ( traits )
+ {
+ result = traits->WaitForThread(m_hThread, waitMode);
+ }
+ else // can't wait for the thread
+ {
+ // so kill it below
+ result = 0xFFFFFFFF;
+ }
+
+ switch ( result )
+ {
+ case 0xFFFFFFFF:
+ // error
+ wxLogSysError(_("Cannot wait for thread termination"));
+ Kill();
+ return wxTHREAD_KILLED;
+
+ case WAIT_OBJECT_0:
+ // thread we're waiting for terminated
+ break;
+
+ case WAIT_OBJECT_0 + 1:
+ // new message arrived, process it -- but only if we're the
+ // main thread as we don't support processing messages in
+ // the other ones
+ //
+ // NB: we still must include QS_ALLINPUT even when waiting
+ // in a secondary thread because if it had created some
+ // window somehow (possible not even using wxWidgets)
+ // the system might dead lock then
+ if ( wxThread::IsMain() )
+ {
+ if ( traits && !traits->DoMessageFromThreadWait() )
+ {
+ // WM_QUIT received: kill the thread
+ Kill();
+
+ return wxTHREAD_KILLED;
+ }
+ }
+ break;
+
+ default:
+ wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
+ }
+ } while ( result != WAIT_OBJECT_0 );
+
+ if ( wxThread::IsMain() )
+ {
+ gs_waitingForThread = false;
+ }
+
+
+ // although the thread might be already in the EXITED state it might not
+ // have terminated yet and so we are not sure that it has actually
+ // terminated if the "if" above hadn't been taken
+ for ( ;; )
+ {
+ if ( !::GetExitCodeThread(m_hThread, &rc) )
+ {
+ wxLogLastError(wxT("GetExitCodeThread"));
+
+ rc = THREAD_ERROR_EXIT;
+
+ break;
+ }
+
+ if ( rc != STILL_ACTIVE )
+ break;
+
+ // give the other thread some time to terminate, otherwise we may be
+ // starving it
+ ::Sleep(1);
+ }
+
+ if ( pRc )
+ *pRc = wxUIntToPtr(rc);
+
+ // we don't need the thread handle any more in any case
+ Free();
+
+
+ return rc == THREAD_ERROR_EXIT ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
}
bool wxThreadInternal::Suspend()
DWORD nSuspendCount = ::SuspendThread(m_hThread);
if ( nSuspendCount == (DWORD)-1 )
{
- wxLogSysError(_("Can not suspend thread %x"), m_hThread);
+ wxLogSysError(_("Cannot suspend thread %lx"),
+ static_cast<unsigned long>(wxPtrToUInt(m_hThread)));
- return FALSE;
+ return false;
}
m_state = STATE_PAUSED;
- return TRUE;
+ return true;
}
bool wxThreadInternal::Resume()
DWORD nSuspendCount = ::ResumeThread(m_hThread);
if ( nSuspendCount == (DWORD)-1 )
{
- wxLogSysError(_("Can not resume thread %x"), m_hThread);
+ wxLogSysError(_("Cannot resume thread %lx"),
+ static_cast<unsigned long>(wxPtrToUInt(m_hThread)));
- return FALSE;
+ return false;
}
// don't change the state from STATE_EXITED because it's special and means
// we are going to terminate without running any user code - if we did it,
- // the codei n Delete() wouldn't work
+ // the code in WaitForTerminate() wouldn't work
if ( m_state != STATE_EXITED )
{
m_state = STATE_RUNNING;
}
- return TRUE;
+ return true;
}
// static functions
return thread;
}
-bool wxThread::IsMain()
-{
- return ::GetCurrentThreadId() == gs_idMainThread;
-}
-
-#ifdef Yield
-#undef Yield
-#endif
-
void wxThread::Yield()
{
// 0 argument to Sleep() is special and means to just give away the rest of
::Sleep(0);
}
-void wxThread::Sleep(unsigned long milliseconds)
-{
- ::Sleep(milliseconds);
-}
-
int wxThread::GetCPUCount()
{
SYSTEM_INFO si;
return si.dwNumberOfProcessors;
}
-bool wxThread::SetConcurrency(size_t level)
+unsigned long wxThread::GetCurrentId()
{
- wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
+ return (unsigned long)::GetCurrentThreadId();
+}
+
+bool wxThread::SetConcurrency(size_t WXUNUSED_IN_WINCE(level))
+{
+#ifdef __WXWINCE__
+ return false;
+#else
+ wxASSERT_MSG( IsMain(), wxT("should only be called from the main thread") );
// ok only for the default one
if ( level == 0 )
// get system affinity mask first
HANDLE hProcess = ::GetCurrentProcess();
- DWORD dwProcMask, dwSysMask;
+ DWORD_PTR dwProcMask, dwSysMask;
if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
{
- wxLogLastError(_T("GetProcessAffinityMask"));
+ wxLogLastError(wxT("GetProcessAffinityMask"));
- return FALSE;
+ return false;
}
// how many CPUs have we got?
dwProcMask |= bit;
// another process added
- if ( !--level )
+ if ( --level == 0 )
{
// and that's enough
break;
// could we set all bits?
if ( level != 0 )
{
- wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
+ wxLogDebug(wxT("bad level %u in wxThread::SetConcurrency()"), level);
- return FALSE;
+ return false;
}
// set it: we can't link to SetProcessAffinityMask() because it doesn't
// exist in Win9x, use RT binding instead
- typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
+ typedef BOOL (WINAPI *SETPROCESSAFFINITYMASK)(HANDLE, DWORD_PTR);
// can use static var because we're always in the main thread here
static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
if ( !pfnSetProcessAffinityMask )
{
- HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
+ HMODULE hModKernel = ::LoadLibrary(wxT("kernel32"));
if ( hModKernel )
{
pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
// we've discovered a MT version of Win9x!
wxASSERT_MSG( pfnSetProcessAffinityMask,
- _T("this system has several CPUs but no SetProcessAffinityMask function?") );
+ wxT("this system has several CPUs but no SetProcessAffinityMask function?") );
}
if ( !pfnSetProcessAffinityMask )
{
// msg given above - do it only once
- return FALSE;
+ return false;
}
if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
{
- wxLogLastError(_T("SetProcessAffinityMask"));
+ wxLogLastError(wxT("SetProcessAffinityMask"));
- return FALSE;
+ return false;
}
- return TRUE;
+ return true;
+#endif // __WXWINCE__/!__WXWINCE__
}
// ctor and dtor
wxThread::wxThread(wxThreadKind kind)
{
- m_internal = new wxThreadInternal();
+ m_internal = new wxThreadInternal(this);
m_isDetached = kind == wxTHREAD_DETACHED;
}
// create/start thread
// -------------------
-wxThreadError wxThread::Create()
+wxThreadError wxThread::Create(unsigned int stackSize)
{
wxCriticalSectionLocker lock(m_critsect);
- if ( !m_internal->Create(this) )
+ if ( !m_internal->Create(this, stackSize) )
return wxTHREAD_NO_RESOURCE;
return wxTHREAD_NO_ERROR;
{
wxCriticalSectionLocker lock(m_critsect);
- if ( m_internal->GetState() != STATE_NEW )
+ // Create the thread if it wasn't created yet with an explicit
+ // Create() call:
+ if ( !m_internal->GetHandle() )
{
- // actually, it may be almost any state at all, not only STATE_RUNNING
- return wxTHREAD_RUNNING;
+ if ( !m_internal->Create(this, 0) )
+ return wxTHREAD_NO_RESOURCE;
}
+ wxCHECK_MSG( m_internal->GetState() == STATE_NEW, wxTHREAD_RUNNING,
+ wxT("thread may only be started once after Create()") );
+
// the thread has just been created and is still suspended - let it run
return Resume();
}
// stopping thread
// ---------------
-wxThread::ExitCode wxThread::Wait()
+wxThread::ExitCode wxThread::Wait(wxThreadWait waitMode)
{
+ ExitCode rc = wxUIntToPtr(THREAD_ERROR_EXIT);
+
// although under Windows we can wait for any thread, it's an error to
// wait for a detached one in wxWin API
- wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
- _T("can't wait for detached thread") );
-
- ExitCode rc = (ExitCode)-1;
+ wxCHECK_MSG( !IsDetached(), rc,
+ wxT("wxThread::Wait(): can't wait for detached thread") );
- (void)Delete(&rc);
-
- m_internal->Free();
+ (void)m_internal->WaitForTerminate(m_critsect, &rc, waitMode);
return rc;
}
-wxThreadError wxThread::Delete(ExitCode *pRc)
+wxThreadError wxThread::Delete(ExitCode *pRc, wxThreadWait waitMode)
{
- ExitCode rc = 0;
-
- // Delete() is always safe to call, so consider all possible states
-
- // we might need to resume the thread, but we might also not need to cancel
- // it if it doesn't run yet
- bool shouldResume = FALSE,
- shouldCancel = TRUE,
- isRunning = FALSE;
-
- // check if the thread already started to run
- {
- wxCriticalSectionLocker lock(m_critsect);
-
- if ( m_internal->GetState() == STATE_NEW )
- {
- // WinThreadStart() will see it and terminate immediately, no need
- // to cancel the thread - but we still need to resume it to let it
- // run
- m_internal->SetState(STATE_EXITED);
-
- Resume(); // it knows about STATE_EXITED special case
-
- shouldCancel = FALSE;
- isRunning = TRUE;
-
- // shouldResume is correctly set to FALSE here
- }
- else
- {
- shouldResume = IsPaused();
- }
- }
-
- // resume the thread if it is paused
- if ( shouldResume )
- Resume();
-
- HANDLE hThread = m_internal->GetHandle();
-
- // does is still run?
- if ( isRunning || IsRunning() )
- {
- if ( IsMain() )
- {
- // set flag for wxIsWaitingForThread()
- gs_waitingForThread = TRUE;
-
-#if wxUSE_GUI
- wxBeginBusyCursor();
-#endif // wxUSE_GUI
- }
-
- // ask the thread to terminate
- if ( shouldCancel )
- {
- wxCriticalSectionLocker lock(m_critsect);
-
- m_internal->Cancel();
- }
-
-#if wxUSE_GUI
- // we can't just wait for the thread to terminate because it might be
- // calling some GUI functions and so it will never terminate before we
- // process the Windows messages that result from these functions
- DWORD result;
- do
- {
- result = ::MsgWaitForMultipleObjects
- (
- 1, // number of objects to wait for
- &hThread, // the objects
- FALSE, // don't wait for all objects
- INFINITE, // no timeout
- QS_ALLEVENTS // return as soon as there are any events
- );
-
- switch ( result )
- {
- case 0xFFFFFFFF:
- // error
- wxLogSysError(_("Can not wait for thread termination"));
- Kill();
- return wxTHREAD_KILLED;
-
- case WAIT_OBJECT_0:
- // thread we're waiting for terminated
- break;
-
- case WAIT_OBJECT_0 + 1:
- // new message arrived, process it
- if ( !wxTheApp->DoMessage() )
- {
- // WM_QUIT received: kill the thread
- Kill();
-
- return wxTHREAD_KILLED;
- }
-
- if ( IsMain() )
- {
- // give the thread we're waiting for chance to exit
- // from the GUI call it might have been in
- if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
- {
- wxMutexGuiLeave();
- }
- }
-
- break;
-
- default:
- wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
- }
- } while ( result != WAIT_OBJECT_0 );
-#else // !wxUSE_GUI
- // simply wait for the thread to terminate
- //
- // OTOH, even console apps create windows (in wxExecute, for WinSock
- // &c), so may be use MsgWaitForMultipleObject() too here?
- if ( WaitForSingleObject(hThread, INFINITE) != WAIT_OBJECT_0 )
- {
- wxFAIL_MSG(wxT("unexpected result of WaitForSingleObject"));
- }
-#endif // wxUSE_GUI/!wxUSE_GUI
-
- if ( IsMain() )
- {
- gs_waitingForThread = FALSE;
-
-#if wxUSE_GUI
- wxEndBusyCursor();
-#endif // wxUSE_GUI
- }
- }
-
- if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
- {
- wxLogLastError(wxT("GetExitCodeThread"));
-
- rc = (ExitCode)-1;
- }
-
- if ( IsDetached() )
- {
- // if the thread exits normally, this is done in WinThreadStart, but in
- // this case it would have been too early because
- // MsgWaitForMultipleObject() would fail if the thread handle was
- // closed while we were waiting on it, so we must do it here
- delete this;
- }
-
- wxASSERT_MSG( (DWORD)rc != STILL_ACTIVE,
- wxT("thread must be already terminated.") );
-
- if ( pRc )
- *pRc = rc;
-
- return rc == (ExitCode)-1 ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
+ return m_internal->WaitForTerminate(m_critsect, pRc, waitMode, this);
}
wxThreadError wxThread::Kill()
if ( !IsRunning() )
return wxTHREAD_NOT_RUNNING;
- if ( !::TerminateThread(m_internal->GetHandle(), (DWORD)-1) )
- {
- wxLogSysError(_("Couldn't terminate thread"));
-
- return wxTHREAD_MISC_ERROR;
- }
-
- m_internal->Free();
+ wxThreadError rc = m_internal->Kill();
if ( IsDetached() )
{
delete this;
}
+ else // joinable
+ {
+ // update the status of the joinable thread
+ wxCriticalSectionLocker lock(m_critsect);
+ m_internal->SetState(STATE_EXITED);
+ }
- return wxTHREAD_NO_ERROR;
+ return rc;
}
void wxThread::Exit(ExitCode status)
{
+ wxThreadInternal::DoThreadOnExit(this);
+
m_internal->Free();
if ( IsDetached() )
{
delete this;
}
+ else // joinable
+ {
+ // update the status of the joinable thread
+ wxCriticalSectionLocker lock(m_critsect);
+ m_internal->SetState(STATE_EXITED);
+ }
#ifdef wxUSE_BEGIN_THREAD
- _endthreadex((unsigned)status);
+ _endthreadex(wxPtrToUInt(status));
#else // !VC++
::ExitThread((DWORD)status);
#endif // VC++/!VC++
unsigned int wxThread::GetPriority() const
{
- wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+ wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
return m_internal->GetPriority();
}
unsigned long wxThread::GetId() const
{
- wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+ wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
return (unsigned long)m_internal->GetId();
}
bool wxThread::IsRunning() const
{
- wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+ wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
return m_internal->GetState() == STATE_RUNNING;
}
bool wxThread::IsAlive() const
{
- wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+ wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
return (m_internal->GetState() == STATE_RUNNING) ||
(m_internal->GetState() == STATE_PAUSED);
bool wxThread::IsPaused() const
{
- wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+ wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
return m_internal->GetState() == STATE_PAUSED;
}
bool wxThread::TestDestroy()
{
- wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+ wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
return m_internal->GetState() == STATE_CANCELED;
}
// words, this should never happen
wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
- return FALSE;
+ return false;
}
// main thread doesn't have associated wxThread object, so store 0 in the
::TlsFree(gs_tlsThisThread);
gs_tlsThisThread = 0xFFFFFFFF;
- wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
+ wxLogSysError(_("Thread module initialization failed: cannot store value in thread local storage"));
- return FALSE;
+ return false;
}
gs_critsectWaitingForGui = new wxCriticalSection();
gs_critsectGui = new wxCriticalSection();
gs_critsectGui->Enter();
- // no error return for GetCurrentThreadId()
- gs_idMainThread = ::GetCurrentThreadId();
+ gs_critsectThreadDelete = new wxCriticalSection;
- return TRUE;
+ wxThread::ms_idMainThread = wxThread::GetCurrentId();
+
+ return true;
}
void wxThreadModule::OnExit()
wxLogLastError(wxT("TlsFree failed."));
}
+ wxDELETE(gs_critsectThreadDelete);
+
if ( gs_critsectGui )
{
gs_critsectGui->Leave();
- delete gs_critsectGui;
- gs_critsectGui = NULL;
+ wxDELETE(gs_critsectGui);
}
- delete gs_critsectWaitingForGui;
- gs_critsectWaitingForGui = NULL;
+ wxDELETE(gs_critsectWaitingForGui);
}
// ----------------------------------------------------------------------------
// not a mutex, so the names are a bit confusing
// ----------------------------------------------------------------------------
-void WXDLLEXPORT wxMutexGuiEnter()
+void wxMutexGuiEnterImpl()
{
// this would dead lock everything...
wxASSERT_MSG( !wxThread::IsMain(),
gs_critsectGui->Enter();
}
-void WXDLLEXPORT wxMutexGuiLeave()
+void wxMutexGuiLeaveImpl()
{
wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
if ( wxThread::IsMain() )
{
- gs_bGuiOwnedByMainThread = FALSE;
+ gs_bGuiOwnedByMainThread = false;
}
else
{
gs_critsectGui->Leave();
}
-void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
+void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
{
wxASSERT_MSG( wxThread::IsMain(),
wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
{
gs_critsectGui->Enter();
- gs_bGuiOwnedByMainThread = TRUE;
+ gs_bGuiOwnedByMainThread = true;
}
//else: already have it, nothing to do
}
}
}
-bool WXDLLEXPORT wxGuiOwnedByMainThread()
+bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
{
return gs_bGuiOwnedByMainThread;
}
// wake up the main thread if it's in ::GetMessage()
-void WXDLLEXPORT wxWakeUpMainThread()
+void WXDLLIMPEXP_BASE wxWakeUpMainThread()
{
// sending any message would do - hopefully WM_NULL is harmless enough
- if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
+ if ( !::PostThreadMessage(wxThread::GetMainId(), WM_NULL, 0, 0) )
{
// should never happen
wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
}
}
-bool WXDLLEXPORT wxIsWaitingForThread()
+bool WXDLLIMPEXP_BASE wxIsWaitingForThread()
{
return gs_waitingForThread;
}
+// ----------------------------------------------------------------------------
+// include common implementation code
+// ----------------------------------------------------------------------------
+
+#include "wx/thrimpl.cpp"
+
#endif // wxUSE_THREADS
projects / wxWidgets.git / blobdiff