// Name: thread.h
// Purpose: Thread API
// Author: Guilhem Lavaux
-// Modified by:
+// Modified by: Vadim Zeitlin (modifications partly inspired by omnithreads
+// package from Olivetti & Oracle Research Laboratory)
// Created: 04/13/98
// RCS-ID: $Id$
// Copyright: (c) Guilhem Lavaux
#ifndef __THREADH__
#define __THREADH__
-#ifdef __GNUG__
-#pragma interface "thread.h"
-#endif
-
// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
+
+// get the value of wxUSE_THREADS configuration flag
#include "wx/setup.h"
#if wxUSE_THREADS
+
+// only for wxUSE_THREADS - otherwise we'd get undefined symbols
+#ifdef __GNUG__
+ #pragma interface "thread.h"
+#endif
+
+// Windows headers define it
+#ifdef Yield
+ #undef Yield
+#endif
+
#include "wx/module.h"
// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------
-typedef enum
+enum wxMutexError
{
- wxMUTEX_NO_ERROR = 0,
- wxMUTEX_DEAD_LOCK, // Mutex has been already locked by THE CALLING thread
- wxMUTEX_BUSY, // Mutex has been already locked by ONE thread
- wxMUTEX_UNLOCKED,
- wxMUTEX_MISC_ERROR
-} wxMutexError;
-
-typedef enum
+ wxMUTEX_NO_ERROR = 0,
+ wxMUTEX_DEAD_LOCK, // Mutex has been already locked by THE CALLING thread
+ wxMUTEX_BUSY, // Mutex has been already locked by ONE thread
+ wxMUTEX_UNLOCKED,
+ wxMUTEX_MISC_ERROR
+};
+
+enum wxThreadError
+{
+ wxTHREAD_NO_ERROR = 0, // No error
+ wxTHREAD_NO_RESOURCE, // No resource left to create a new thread
+ wxTHREAD_RUNNING, // The thread is already running
+ wxTHREAD_NOT_RUNNING, // The thread isn't running
+ wxTHREAD_KILLED, // Thread we waited for had to be killed
+ wxTHREAD_MISC_ERROR // Some other error
+};
+
+enum wxThreadKind
{
- wxTHREAD_NO_ERROR = 0, // No error
- wxTHREAD_NO_RESOURCE, // No resource left to create a new thread
- wxTHREAD_RUNNING, // The thread is already running
- wxTHREAD_NOT_RUNNING, // The thread isn't running
- wxTHREAD_MISC_ERROR // Some other error
-} wxThreadError;
-
-/* defines the interval of priority. */
-#define WXTHREAD_MIN_PRIORITY 0
-#define WXTHREAD_DEFAULT_PRIORITY 50
-#define WXTHREAD_MAX_PRIORITY 100
+ wxTHREAD_DETACHED,
+ wxTHREAD_JOINABLE
+};
+
+// defines the interval of priority
+enum
+{
+ WXTHREAD_MIN_PRIORITY = 0u,
+ WXTHREAD_DEFAULT_PRIORITY = 50u,
+ WXTHREAD_MAX_PRIORITY = 100u
+};
// ----------------------------------------------------------------------------
// A mutex object is a synchronization object whose state is set to signaled
// you should consider wxMutexLocker whenever possible instead of directly
// working with wxMutex class - it is safer
+class WXDLLEXPORT wxConditionInternal;
class WXDLLEXPORT wxMutexInternal;
-class WXDLLEXPORT wxMutex
+class WXDLLEXPORT wxMutex
{
public:
- // constructor & destructor
+ // constructor & destructor
wxMutex();
~wxMutex();
bool IsLocked() const { return (m_locked > 0); }
protected:
- friend class wxCondition;
-
// no assignment operator nor copy ctor
wxMutex(const wxMutex&);
wxMutex& operator=(const wxMutex&);
int m_locked;
- wxMutexInternal *p_internal;
+ wxMutexInternal *m_internal;
+
+ friend class wxConditionInternal;
};
// a helper class which locks the mutex in the ctor and unlocks it in the dtor:
{
public:
// lock the mutex in the ctor
- wxMutexLocker(wxMutex *mutex)
- { m_isOk = mutex && ((m_mutex = mutex)->Lock() == wxMUTEX_NO_ERROR); }
+ wxMutexLocker(wxMutex& mutex)
+ : m_isOk(FALSE), m_mutex(mutex)
+ { m_isOk = ( m_mutex.Lock() == wxMUTEX_NO_ERROR ); }
// returns TRUE if mutex was successfully locked in ctor
- bool IsOk() const { return m_isOk; }
+ bool IsOk() const
+ { return m_isOk; }
// unlock the mutex in dtor
- ~wxMutexLocker() { if ( IsOk() ) m_mutex->Unlock(); }
+ ~wxMutexLocker()
+ { if ( IsOk() ) m_mutex.Unlock(); }
private:
// no assignment operator nor copy ctor
wxMutexLocker& operator=(const wxMutexLocker&);
bool m_isOk;
- wxMutex *m_mutex;
+ wxMutex& m_mutex;
};
// ----------------------------------------------------------------------------
// Critical section: this is the same as mutex but is only visible to the
// threads of the same process. For the platforms which don't have native
// support for critical sections, they're implemented entirely in terms of
-// mutexes
+// mutexes.
+//
+// NB: wxCriticalSection object does not allocate any memory in its ctor
+// which makes it possible to have static globals of this class
// ----------------------------------------------------------------------------
-// you should consider wxCriticalSectionLocker whenever possible instead of
-// directly working with wxCriticalSection class - it is safer
-#ifdef __WXMSW__
- class WXDLLEXPORT wxCriticalSectionInternal;
- #define WXCRITICAL_INLINE
-#else // !MSW
+class WXDLLEXPORT wxCriticalSectionInternal;
+
+// in order to avoid any overhead under platforms where critical sections are
+// just mutexes make all wxCriticalSection class functions inline
+#if !defined(__WXMSW__) && !defined(__WXPM__)
#define WXCRITICAL_INLINE inline
+
+ #define wxCRITSECT_IS_MUTEX 1
+#else // MSW || OS2
+ #define WXCRITICAL_INLINE
+
+ #define wxCRITSECT_IS_MUTEX 0
#endif // MSW/!MSW
+
+// you should consider wxCriticalSectionLocker whenever possible instead of
+// directly working with wxCriticalSection class - it is safer
class WXDLLEXPORT wxCriticalSection
{
public:
WXCRITICAL_INLINE ~wxCriticalSection();
// enter the section (the same as locking a mutex)
- void WXCRITICAL_INLINE Enter();
+ WXCRITICAL_INLINE void Enter();
// leave the critical section (same as unlocking a mutex)
- void WXCRITICAL_INLINE Leave();
+ WXCRITICAL_INLINE void Leave();
private:
// no assignment operator nor copy ctor
wxCriticalSection(const wxCriticalSection&);
wxCriticalSection& operator=(const wxCriticalSection&);
-#ifdef __WXMSW__
- wxCriticalSectionInternal *m_critsect;
-#else // !MSW
+#if wxCRITSECT_IS_MUTEX
wxMutex m_mutex;
-#endif // MSW/!MSW
+#elif defined(__WXMSW__)
+ // we can't allocate any memory in the ctor, so use placement new -
+ // unfortunately, we have to hardcode the sizeof() here because we can't
+ // include windows.h from this public header
+ char m_buffer[24];
+#elif !defined(__WXPM__)
+ wxCriticalSectionInternal *m_critsect;
+#else
+ // nothing for OS/2
+#endif // !Unix/Unix
};
+// keep your preprocessor name space clean
+#undef WXCRITICAL_INLINE
+
// wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
// to th mutexes
class WXDLLEXPORT wxCriticalSectionLocker
{
public:
- wxCriticalSectionLocker(wxCriticalSection& critsect) : m_critsect(critsect)
- { m_critsect.Enter(); }
- ~wxCriticalSectionLocker()
- { m_critsect.Leave(); }
+ inline wxCriticalSectionLocker(wxCriticalSection& critsect);
+ inline ~wxCriticalSectionLocker();
private:
// no assignment operator nor copy ctor
};
// ----------------------------------------------------------------------------
-// Condition handler.
+// wxCondition models a POSIX condition variable which allows one (or more)
+// thread(s) to wait until some condition is fulfilled
// ----------------------------------------------------------------------------
-class wxConditionInternal;
-class WXDLLEXPORT wxCondition
+class WXDLLEXPORT wxCondition
{
+ DECLARE_NO_COPY_CLASS(wxCondition)
+
public:
- // constructor & destructor
- wxCondition();
- ~wxCondition();
-
- // Waits indefinitely.
- void Wait(wxMutex& mutex);
- // Waits until a signal is raised or the timeout is elapsed.
- bool Wait(wxMutex& mutex, unsigned long sec, unsigned long nsec);
- // Raises a signal: only one "Waiter" is released.
- void Signal();
- // Broadcasts to all "Waiters".
- void Broadcast();
+ // constructor and destructor
+
+ // Each wxCondition object is associated with with a wxMutex object The
+ // mutex object MUST be locked before calling Wait()
+ wxCondition(wxMutex& mutex);
+
+ // dtor is not virtual, don't use this class polymorphically
+ ~wxCondition();
+
+ // NB: the associated mutex MUST be locked beforehand by the calling thread
+ //
+ // it atomically releases the lock on the associated mutex
+ // and starts waiting to be woken up by a Signal()/Broadcast()
+ // once its signaled, then it will wait until it can reacquire
+ // the lock on the associated mutex object, before returning.
+ void Wait();
+
+ // exactly as Wait() except that it may also return if the specified
+ // timeout ellapses even if the condition hasn't been signalled: in this
+ // case, the return value is FALSE, otherwise (i.e. in case of a normal
+ // return) it is TRUE
+ //
+ // the timeeout parameter specifies a interval that needs to be waited in
+ // milliseconds
+ bool Wait( unsigned long timeout_millis );
+
+ // NB: the associated mutex may or may not be locked by the calling thread
+ //
+ // this method unblocks one thread if any are blocking on the condition.
+ // if no thread is blocking in Wait(), then the signal is NOT remembered
+ // The thread which was blocking on Wait(), will then reacquire the lock
+ // on the associated mutex object before returning
+ void Signal();
+
+ // NB: the associated mutex may or may not be locked by the calling thread
+ //
+ // this method unblocks all threads if any are blocking on the condition.
+ // if no thread is blocking in Wait(), then the signal is NOT remembered
+ // The threads which were blocking on Wait(), will then reacquire the lock
+ // on the associated mutex object before returning.
+ void Broadcast();
private:
- wxConditionInternal *p_internal;
+ wxConditionInternal *m_internal;
};
// ----------------------------------------------------------------------------
-// Thread management class
+// wxSemaphore: a counter limiting the number of threads concurrently accessing
+// a shared resource
// ----------------------------------------------------------------------------
-class wxThreadInternal;
-class WXDLLEXPORT wxThread
+class WXDLLEXPORT wxSemaphoreInternal;
+class WXDLLEXPORT wxSemaphore
{
+ DECLARE_NO_COPY_CLASS(wxSemaphore)
+
public:
- // constructor & destructor.
- wxThread();
- virtual ~wxThread();
+ // specifying a maxcount of 0 actually makes wxSemaphore behave as if there
+ // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex
+ wxSemaphore( int initialcount = 0, int maxcount = 0 );
- // Create a new thread, this method should check there is only one thread
- // running by object.
- wxThreadError Create();
+ // dtor is not virtual, don't use this class polymorphically
+ ~wxSemaphore();
- // Destroys the thread immediately if the defer flag isn't true.
- wxThreadError Destroy();
+ // wait indefinitely, until the semaphore count goes beyond 0
+ // and then decrement it and return (this method might have been called
+ // Acquire())
+ void Wait();
- // Pause a running thread
- wxThreadError Pause();
+ // same as Wait(), but does not block, returns TRUE if successful and
+ // FALSE if the count is zero
+ bool TryWait();
- // Resume a paused thread
- wxThreadError Resume();
+ // same as Wait(), but as a timeout limit, returns TRUE if the semaphore
+ // was acquired and FALSE if the timeout has ellapsed
+ bool Wait( unsigned long timeout_millis );
- // Switches on the defer flag.
- void DeferDestroy(bool on);
+ // increments the semaphore count and signals one of the waiting threads
+ void Post();
- // Waits for the termination of the thread.
- void *Join();
+private:
+ wxSemaphoreInternal *m_internal;
+};
- // Sets the priority to "prio". (Warning: The priority can only be set before
- // the thread is created)
- void SetPriority(int prio);
- // Get the current priority.
- int GetPriority() const;
+// ----------------------------------------------------------------------------
+// wxThread: class encpasulating a thread of execution
+// ----------------------------------------------------------------------------
- // Get the thread ID
- unsigned long GetID() const;
+// there are two different kinds of threads: joinable and detached (default)
+// ones. Only joinable threads can return a return code and only detached
+// threads auto-delete themselves - the user should delete the joinable
+// threads manually.
- // Returns true if the thread is alive.
- bool IsAlive() const;
- // Returns true if the thread is running (not paused, not killed).
- bool IsRunning() const;
- // Returns true if the thread is suspended
- bool IsPaused() const { return IsAlive() && !IsRunning(); }
+// NB: in the function descriptions the words "this thread" mean the thread
+// created by the wxThread object while "main thread" is the thread created
+// during the process initialization (a.k.a. the GUI thread)
- // Returns true if current thread is the main thread (aka the GUI thread)
- static bool IsMain();
+// On VMS thread pointers are 64 bits (also needed for other systems???
+#ifdef __VMS
+ typedef unsigned long long wxThreadIdType;
+#else
+ typedef unsigned long wxThreadIdType;
+#endif
- // Called when thread exits.
- virtual void OnExit();
+class wxThreadInternal;
+class WXDLLEXPORT wxThread
+{
+public:
+ // the return type for the thread function
+ typedef void *ExitCode;
+
+ // static functions
+ // Returns the wxThread object for the calling thread. NULL is returned
+ // if the caller is the main thread (but it's recommended to use
+ // IsMain() and only call This() for threads other than the main one
+ // because NULL is also returned on error). If the thread wasn't
+ // created with wxThread class, the returned value is undefined.
+ static wxThread *This();
+
+ // Returns true if current thread is the main thread.
+ static bool IsMain();
+
+ // Release the rest of our time slice leting the other threads run
+ static void Yield();
+
+ // Sleep during the specified period of time in milliseconds
+ //
+ // NB: at least under MSW worker threads can not call ::wxSleep()!
+ static void Sleep(unsigned long milliseconds);
+
+ // get the number of system CPUs - useful with SetConcurrency()
+ // (the "best" value for it is usually number of CPUs + 1)
+ //
+ // Returns -1 if unknown, number of CPUs otherwise
+ static int GetCPUCount();
+
+ // Get the platform specific thread ID and return as a long. This
+ // can be used to uniquely identify threads, even if they are not
+ // wxThreads. This is used by wxPython.
+ static wxThreadIdType GetCurrentId();
+
+ // sets the concurrency level: this is, roughly, the number of threads
+ // the system tries to schedule to run in parallel. 0 means the
+ // default value (usually acceptable, but may not yield the best
+ // performance for this process)
+ //
+ // Returns TRUE on success, FALSE otherwise (if not implemented, for
+ // example)
+ static bool SetConcurrency(size_t level);
+
+ // constructor only creates the C++ thread object and doesn't create (or
+ // start) the real thread
+ wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
+
+ // functions that change the thread state: all these can only be called
+ // from _another_ thread (typically the thread that created this one, e.g.
+ // the main thread), not from the thread itself
+
+ // create a new thread and optionally set the stack size on
+ // platforms that support that - call Run() to start it
+ // (special cased for watcom which won't accept 0 default)
+
+ wxThreadError Create(unsigned int stackSize = 0);
+
+ // starts execution of the thread - from the moment Run() is called
+ // the execution of wxThread::Entry() may start at any moment, caller
+ // shouldn't suppose that it starts after (or before) Run() returns.
+ wxThreadError Run();
+
+ // stops the thread if it's running and deletes the wxThread object if
+ // this is a detached thread freeing its memory - otherwise (for
+ // joinable threads) you still need to delete wxThread object
+ // yourself.
+ //
+ // this function only works if the thread calls TestDestroy()
+ // periodically - the thread will only be deleted the next time it
+ // does it!
+ //
+ // will fill the rc pointer with the thread exit code if it's !NULL
+ wxThreadError Delete(ExitCode *rc = (ExitCode *)NULL);
+
+ // waits for a joinable thread to finish and returns its exit code
+ //
+ // Returns (ExitCode)-1 on error (for example, if the thread is not
+ // joinable)
+ ExitCode Wait();
+
+ // kills the thread without giving it any chance to clean up - should
+ // not be used in normal circumstances, use Delete() instead. It is a
+ // dangerous function that should only be used in the most extreme
+ // cases!
+ //
+ // The wxThread object is deleted by Kill() if the thread is
+ // detachable, but you still have to delete it manually for joinable
+ // threads.
+ wxThreadError Kill();
+
+ // pause a running thread: as Delete(), this only works if the thread
+ // calls TestDestroy() regularly
+ wxThreadError Pause();
+
+ // resume a paused thread
+ wxThreadError Resume();
+
+ // priority
+ // Sets the priority to "prio": see WXTHREAD_XXX_PRIORITY constants
+ //
+ // NB: the priority can only be set before the thread is created
+ void SetPriority(unsigned int prio);
+
+ // Get the current priority.
+ unsigned int GetPriority() const;
+
+ // thread status inquiries
+ // Returns true if the thread is alive: i.e. running or suspended
+ bool IsAlive() const;
+ // Returns true if the thread is running (not paused, not killed).
+ bool IsRunning() const;
+ // Returns true if the thread is suspended
+ bool IsPaused() const;
+
+ // is the thread of detached kind?
+ bool IsDetached() const { return m_isDetached; }
+
+ // Get the thread ID - a platform dependent number which uniquely
+ // identifies a thread inside a process
+ wxThreadIdType GetId() const;
+
+ // called when the thread exits - in the context of this thread
+ //
+ // NB: this function will not be called if the thread is Kill()ed
+ virtual void OnExit() { }
+
+ // dtor is public, but the detached threads should never be deleted - use
+ // Delete() instead (or leave the thread terminate by itself)
+ virtual ~wxThread();
protected:
- // Returns TRUE if the thread was asked to terminate
- bool TestDestroy();
+ // Returns TRUE if the thread was asked to terminate: this function should
+ // be called by the thread from time to time, otherwise the main thread
+ // will be left forever in Delete()!
+ bool TestDestroy();
- // Exits from the current thread.
- void Exit(void *status = NULL);
+ // exits from the current thread - can be called only from this thread
+ void Exit(ExitCode exitcode = 0);
-private:
- // Entry point for the thread.
- virtual void *Entry() = 0;
+ // entry point for the thread - called by Run() and executes in the context
+ // of this thread.
+ virtual void *Entry() = 0;
private:
- friend class wxThreadInternal;
+ // no copy ctor/assignment operator
+ wxThread(const wxThread&);
+ wxThread& operator=(const wxThread&);
+
+ friend class wxThreadInternal;
+
+ // the (platform-dependent) thread class implementation
+ wxThreadInternal *m_internal;
+
+ // protects access to any methods of wxThreadInternal object
+ wxCriticalSection m_critsect;
- wxThreadInternal *p_internal;
+ // true if the thread is detached, false if it is joinable
+ bool m_isDetached;
};
// ----------------------------------------------------------------------------
void WXDLLEXPORT wxMutexGuiEnter();
void WXDLLEXPORT wxMutexGuiLeave();
+// macros for entering/leaving critical sections which may be used without
+// having to take them inside "#if wxUSE_THREADS"
+#define wxENTER_CRIT_SECT(cs) (cs).Enter()
+#define wxLEAVE_CRIT_SECT(cs) (cs).Leave()
+#define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
+#define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs)
+
#else // !wxUSE_THREADS
+#include "wx/defs.h" // for WXDLLEXPORT
+
// no thread support
inline void WXDLLEXPORT wxMutexGuiEnter() { }
inline void WXDLLEXPORT wxMutexGuiLeave() { }
+// macros for entering/leaving critical sections which may be used without
+// having to take them inside "#if wxUSE_THREADS"
+#define wxENTER_CRIT_SECT(cs)
+#define wxLEAVE_CRIT_SECT(cs)
+#define wxCRIT_SECT_DECLARE(cs)
+#define wxCRIT_SECT_LOCKER(name, cs)
+
#endif // wxUSE_THREADS
// automatically unlock GUI mutex in dtor
// -----------------------------------------------------------------------------
// implementation only until the end of file
// -----------------------------------------------------------------------------
-#ifdef wxUSE_THREADS
-#ifdef __WXMSW__
+
+#if wxUSE_THREADS
+
+#if defined(__WXMSW__)
// unlock GUI if there are threads waiting for and lock it back when
// there are no more of them - should be called periodically by the main
// thread
- void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
+ extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
// returns TRUE if the main thread has GUI lock
- bool WXDLLEXPORT wxGuiOwnedByMainThread();
+ extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
// wakes up the main thread if it's sleeping inside ::GetMessage()
- void WXDLLEXPORT wxWakeUpMainThread();
-#else // !MSW
+ extern void WXDLLEXPORT wxWakeUpMainThread();
+
+ // return TRUE if the main thread is waiting for some other to terminate:
+ // wxApp then should block all "dangerous" messages
+ extern bool WXDLLEXPORT wxIsWaitingForThread();
+#elif defined(__WXMAC__)
+ extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
+
+ // returns TRUE if the main thread has GUI lock
+ extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
+
+ // wakes up the main thread if it's sleeping inside ::GetMessage()
+ extern void WXDLLEXPORT wxWakeUpMainThread();
+
+ // return TRUE if the main thread is waiting for some other to terminate:
+ // wxApp then should block all "dangerous" messages
+ extern bool WXDLLEXPORT wxIsWaitingForThread();
+
+ // implement wxCriticalSection using mutexes
+ inline wxCriticalSection::wxCriticalSection() : m_mutex() { }
+ inline wxCriticalSection::~wxCriticalSection() { }
+
+ inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
+ inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
+#elif defined(__WXPM__)
+ // unlock GUI if there are threads waiting for and lock it back when
+ // there are no more of them - should be called periodically by the main
+ // thread
+ extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
+
+ // returns TRUE if the main thread has GUI lock
+ extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
+
+ // return TRUE if the main thread is waiting for some other to terminate:
+ // wxApp then should block all "dangerous" messages
+ extern bool WXDLLEXPORT wxIsWaitingForThread();
+
+#else // !MSW && !PM
// implement wxCriticalSection using mutexes
inline wxCriticalSection::wxCriticalSection() { }
inline wxCriticalSection::~wxCriticalSection() { }
inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
#endif // MSW/!MSW
+
+ // we can define these inline functions now (they should be defined after
+ // wxCriticalSection::Enter/Leave)
+ inline
+ wxCriticalSectionLocker:: wxCriticalSectionLocker(wxCriticalSection& cs)
+ : m_critsect(cs) { m_critsect.Enter(); }
+ inline
+ wxCriticalSectionLocker::~wxCriticalSectionLocker() { m_critsect.Leave(); }
#endif // wxUSE_THREADS
#endif // __THREADH__
+
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