X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/be52b34172dede7460990c54b9f7e2dad3a6f876..c17ba76f38f7ef27a8a8f3710727a365e9c23de1:/include/wx/thread.h diff --git a/include/wx/thread.h b/include/wx/thread.h index 319829ba71..8652d6cbf8 100644 --- a/include/wx/thread.h +++ b/include/wx/thread.h @@ -1,5 +1,5 @@ ///////////////////////////////////////////////////////////////////////////// -// Name: thread.h +// Name: wx/thread.h // Purpose: Thread API // Author: Guilhem Lavaux // Modified by: Vadim Zeitlin (modifications partly inspired by omnithreads @@ -10,20 +10,20 @@ // Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// -#ifndef __THREADH__ -#define __THREADH__ +#ifndef _WX_THREAD_H_ +#define _WX_THREAD_H_ // ---------------------------------------------------------------------------- // headers // ---------------------------------------------------------------------------- // get the value of wxUSE_THREADS configuration flag -#include "wx/setup.h" +#include "wx/defs.h" #if wxUSE_THREADS // only for wxUSE_THREADS - otherwise we'd get undefined symbols -#ifdef __GNUG__ +#if defined(__GNUG__) && !defined(__APPLE__) #pragma interface "thread.h" #endif @@ -40,11 +40,30 @@ 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 + wxMUTEX_NO_ERROR = 0, // operation completed successfully + wxMUTEX_INVALID, // mutex hasn't been initialized + wxMUTEX_DEAD_LOCK, // mutex is already locked by the calling thread + wxMUTEX_BUSY, // mutex is already locked by another thread + wxMUTEX_UNLOCKED, // attempt to unlock a mutex which is not locked + wxMUTEX_MISC_ERROR // any other error +}; + +enum wxCondError +{ + wxCOND_NO_ERROR = 0, + wxCOND_INVALID, + wxCOND_TIMEOUT, // WaitTimeout() has timed out + wxCOND_MISC_ERROR +}; + +enum wxSemaError +{ + wxSEMA_NO_ERROR = 0, + wxSEMA_INVALID, // semaphore hasn't been initialized successfully + wxSEMA_BUSY, // returned by TryWait() if Wait() would block + wxSEMA_TIMEOUT, // returned by WaitTimeout() + wxSEMA_OVERFLOW, // Post() would increase counter past the max + wxSEMA_MISC_ERROR }; enum wxThreadError @@ -71,6 +90,37 @@ enum WXTHREAD_MAX_PRIORITY = 100u }; +// There are 2 types of mutexes: normal mutexes and recursive ones. The attempt +// to lock a normal mutex by a thread which already owns it results in +// undefined behaviour (it always works under Windows, it will almost always +// result in a deadlock under Unix). Locking a recursive mutex in such +// situation always succeeds and it must be unlocked as many times as it has +// been locked. +// +// However recursive mutexes have several important drawbacks: first, in the +// POSIX implementation, they're less efficient. Second, and more importantly, +// they CAN NOT BE USED WITH CONDITION VARIABLES under Unix! Using them with +// wxCondition will work under Windows and some Unices (notably Linux) but will +// deadlock under other Unix versions (e.g. Solaris). As it might be difficult +// to ensure that a recursive mutex is not used with wxCondition, it is a good +// idea to avoid using recursive mutexes at all. Also, the last problem with +// them is that some (older) Unix versions don't support this at all -- which +// results in a configure warning when building and a deadlock when using them. +enum wxMutexType +{ + // normal mutex: try to always use this one + wxMUTEX_DEFAULT, + + // recursive mutex: don't use these ones with wxCondition + wxMUTEX_RECURSIVE +}; + +// forward declarations +class WXDLLEXPORT wxConditionInternal; +class WXDLLEXPORT wxMutexInternal; +class WXDLLEXPORT wxSemaphoreInternal; +class WXDLLEXPORT wxThreadInternal; + // ---------------------------------------------------------------------------- // A mutex object is a synchronization object whose state is set to signaled // when it is not owned by any thread, and nonsignaled when it is owned. Its @@ -80,34 +130,44 @@ enum // 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 { public: // constructor & destructor - wxMutex(); + // ------------------------ + + // create either default (always safe) or recursive mutex + wxMutex(wxMutexType mutexType = wxMUTEX_DEFAULT); + + // destroys the mutex kernel object ~wxMutex(); - // Lock the mutex. + // test if the mutex has been created successfully + bool IsOk() const; + + // mutex operations + // ---------------- + + // Lock the mutex, blocking on it until it is unlocked by the other thread. + // The result of locking a mutex already locked by the current thread + // depend on the mutex type. + // + // The caller must call Unlock() later if Lock() returned wxMUTEX_NO_ERROR. wxMutexError Lock(); - // Try to lock the mutex: if it can't, returns immediately with an error. + + // Try to lock the mutex: if it is currently locked, return immediately + // with an error. Otherwise the caller must call Unlock(). wxMutexError TryLock(); - // Unlock the mutex. - wxMutexError Unlock(); - // Returns true if the mutex is locked. - bool IsLocked() const { return (m_locked > 0); } + // Unlock the mutex. It is an error to unlock an already unlocked mutex + wxMutexError Unlock(); protected: - // no assignment operator nor copy ctor - wxMutex(const wxMutex&); - wxMutex& operator=(const wxMutex&); - - int m_locked; wxMutexInternal *m_internal; friend class wxConditionInternal; + + DECLARE_NO_COPY_CLASS(wxMutex) }; // a helper class which locks the mutex in the ctor and unlocks it in the dtor: @@ -148,18 +208,16 @@ private: // which makes it possible to have static globals of this class // ---------------------------------------------------------------------------- -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_INLINE inline +#else // MSW || OS2 #define wxCRITSECT_IS_MUTEX 0 + + #define wxCRITSECT_INLINE #endif // MSW/!MSW // you should consider wxCriticalSectionLocker whenever possible instead of @@ -168,50 +226,77 @@ class WXDLLEXPORT wxCriticalSection { public: // ctor & dtor - WXCRITICAL_INLINE wxCriticalSection(); - WXCRITICAL_INLINE ~wxCriticalSection(); + wxCRITSECT_INLINE wxCriticalSection(); + wxCRITSECT_INLINE ~wxCriticalSection(); // enter the section (the same as locking a mutex) - WXCRITICAL_INLINE void Enter(); + wxCRITSECT_INLINE void Enter(); + // leave the critical section (same as unlocking a mutex) - WXCRITICAL_INLINE void Leave(); + wxCRITSECT_INLINE void Leave(); private: - // no assignment operator nor copy ctor - wxCriticalSection(const wxCriticalSection&); - wxCriticalSection& operator=(const wxCriticalSection&); - #if wxCRITSECT_IS_MUTEX wxMutex m_mutex; #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; + // include windows.h from this public header and we also have to use the + // union to force the correct (i.e. maximal) alignment + // + // if CRITICAL_SECTION size changes in Windows, you'll get an assert from + // thread.cpp and will need to increase the buffer size + // + // finally, we need this typedef instead of declaring m_buffer directly + // because otherwise the assert mentioned above wouldn't compile with some + // compilers (notably CodeWarrior 8) + typedef char wxCritSectBuffer[24]; + union + { + unsigned long m_dummy1; + void *m_dummy2; + + wxCritSectBuffer m_buffer; + }; #else // nothing for OS/2 -#endif // !Unix/Unix +#endif // Unix/Win32/OS2 + + DECLARE_NO_COPY_CLASS(wxCriticalSection) }; -// keep your preprocessor name space clean -#undef WXCRITICAL_INLINE +#if wxCRITSECT_IS_MUTEX + // 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 // wxCRITSECT_IS_MUTEX + +#undef wxCRITSECT_INLINE +#undef wxCRITSECT_IS_MUTEX // wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is // to th mutexes class WXDLLEXPORT wxCriticalSectionLocker { public: - inline wxCriticalSectionLocker(wxCriticalSection& critsect); - inline ~wxCriticalSectionLocker(); + wxCriticalSectionLocker(wxCriticalSection& cs) + : m_critsect(cs) + { + m_critsect.Enter(); + } -private: - // no assignment operator nor copy ctor - wxCriticalSectionLocker(const wxCriticalSectionLocker&); - wxCriticalSectionLocker& operator=(const wxCriticalSectionLocker&); + ~wxCriticalSectionLocker() + { + m_critsect.Leave(); + } +private: wxCriticalSection& m_critsect; + + DECLARE_NO_COPY_CLASS(wxCriticalSectionLocker) }; // ---------------------------------------------------------------------------- @@ -221,25 +306,24 @@ private: class WXDLLEXPORT wxCondition { - DECLARE_NO_COPY_CLASS(wxCondition) - public: - // constructor and destructor - - // Each wxCondition object is associated with with a wxMutex object The - // mutex object MUST be locked before calling Wait() + // Each wxCondition object is associated with a (single) 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(); + // return TRUE if the condition has been created successfully + bool IsOk() const; + // 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(); + wxCondError 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 @@ -248,7 +332,7 @@ public: // // the timeeout parameter specifies a interval that needs to be waited in // milliseconds - bool Wait( unsigned long timeout_millis ); + wxCondError WaitTimeout(unsigned long milliseconds); // NB: the associated mutex may or may not be locked by the calling thread // @@ -256,7 +340,7 @@ public: // 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(); + wxCondError Signal(); // NB: the associated mutex may or may not be locked by the calling thread // @@ -264,10 +348,17 @@ public: // 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(); + wxCondError Broadcast(); + + + // deprecated version, don't use + bool Wait(unsigned long milliseconds) + { return WaitTimeout(milliseconds) == wxCOND_NO_ERROR; } private: wxConditionInternal *m_internal; + + DECLARE_NO_COPY_CLASS(wxCondition) }; // ---------------------------------------------------------------------------- @@ -275,11 +366,8 @@ private: // a shared resource // ---------------------------------------------------------------------------- -class WXDLLEXPORT wxSemaphoreInternal; class WXDLLEXPORT wxSemaphore { - DECLARE_NO_COPY_CLASS(wxSemaphore) - public: // 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 @@ -288,24 +376,29 @@ public: // dtor is not virtual, don't use this class polymorphically ~wxSemaphore(); + // return TRUE if the semaphore has been created successfully + bool IsOk() const; + // wait indefinitely, until the semaphore count goes beyond 0 // and then decrement it and return (this method might have been called // Acquire()) - void Wait(); + wxSemaError Wait(); - // same as Wait(), but does not block, returns TRUE if successful and - // FALSE if the count is zero - bool TryWait(); + // same as Wait(), but does not block, returns wxSEMA_NO_ERROR if + // successful and wxSEMA_BUSY if the count is currently zero + wxSemaError TryWait(); - // 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 ); + // same as Wait(), but as a timeout limit, returns wxSEMA_NO_ERROR if the + // semaphore was acquired and wxSEMA_TIMEOUT if the timeout has ellapsed + wxSemaError WaitTimeout(unsigned long milliseconds); // increments the semaphore count and signals one of the waiting threads - void Post(); + wxSemaError Post(); private: wxSemaphoreInternal *m_internal; + + DECLARE_NO_COPY_CLASS(wxSemaphore) }; // ---------------------------------------------------------------------------- @@ -328,7 +421,6 @@ private: typedef unsigned long wxThreadIdType; #endif -class wxThreadInternal; class WXDLLEXPORT wxThread { public: @@ -508,8 +600,6 @@ void WXDLLEXPORT wxMutexGuiLeave(); #else // !wxUSE_THREADS -#include "wx/defs.h" // for WXDLLEXPORT - // no thread support inline void WXDLLEXPORT wxMutexGuiEnter() { } inline void WXDLLEXPORT wxMutexGuiLeave() { } @@ -521,9 +611,30 @@ inline void WXDLLEXPORT wxMutexGuiLeave() { } #define wxCRIT_SECT_DECLARE(cs) #define wxCRIT_SECT_LOCKER(name, cs) -#endif // wxUSE_THREADS +#endif // wxUSE_THREADS/!wxUSE_THREADS -// automatically unlock GUI mutex in dtor +// mark part of code as being a critical section: this macro declares a +// critical section with the given name and enters it immediately and leaves +// it at the end of the current scope +// +// example: +// +// int Count() +// { +// static int s_counter = 0; +// +// wxCRITICAL_SECTION(counter); +// +// return ++s_counter; +// } +// +// this function is MT-safe in presence of the threads but there is no +// overhead when the library is compiled without threads +#define wxCRITICAL_SECTION(name) \ + wxCRIT_SECT_DECLARE(s_cs##name); \ + wxCRIT_SECT_LOCKER(cs##name##Locker, s_cs##name) + +// automatically lock GUI mutex in ctor and unlock it in dtor class WXDLLEXPORT wxMutexGuiLocker { public: @@ -537,7 +648,7 @@ public: #if wxUSE_THREADS -#if defined(__WXMSW__) +#if defined(__WXMSW__) || defined(__WXMAC__) || 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 @@ -546,61 +657,17 @@ public: // returns TRUE if the main thread has GUI lock extern bool WXDLLEXPORT wxGuiOwnedByMainThread(); +#ifndef __WXPM__ // wakes up the main thread if it's sleeping inside ::GetMessage() extern void WXDLLEXPORT wxWakeUpMainThread(); +#endif // !OS/2 // 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 +#endif // MSW, Mac, OS/2 - // 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__ +#endif // _WX_THREAD_H_