X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/75ed1d15d0d866cac78f7c0da176db8dd5288bc8..19e30148e18cc99296b26503c155e5cef59045f4:/include/wx/thread.h diff --git a/include/wx/thread.h b/include/wx/thread.h index 99091a44ab..60f5c7c5c4 100644 --- a/include/wx/thread.h +++ b/include/wx/thread.h @@ -2,7 +2,8 @@ // 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 @@ -12,148 +13,589 @@ #ifndef __THREADH__ #define __THREADH__ +// ---------------------------------------------------------------------------- +// 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" + #pragma interface "thread.h" #endif -#include "wx/object.h" -#include "wx/setup.h" +// Windows headers define it +#ifdef Yield + #undef Yield +#endif + +#include "wx/module.h" + +// ---------------------------------------------------------------------------- +// constants +// ---------------------------------------------------------------------------- + +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 +}; + +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_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 +// when it is not owned by any thread, and nonsignaled when it is owned. Its +// name comes from its usefulness in coordinating mutually-exclusive access to +// a shared resource. Only one thread at a time can own a mutex object. +// ---------------------------------------------------------------------------- -typedef enum { - MUTEX_NO_ERROR=0, - MUTEX_DEAD_LOCK, // Mutex has been already locked by THE CALLING thread - MUTEX_BUSY, // Mutex has been already locked by ONE thread - MUTEX_UNLOCKED -} wxMutexError; - -typedef enum { - THREAD_NO_ERROR=0, // No error - THREAD_NO_RESOURCE, // No resource left to create a new thread - THREAD_RUNNING, // The thread is already running - THREAD_NOT_RUNNING, // The thread isn't running - THREAD_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 - -// --------------------------------------------------------------------------- -// Mutex handler +// 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 - wxMutex(); - ~wxMutex(); - - // Lock the mutex. - wxMutexError Lock(); - // Try to lock the mutex: if it can't, returns immediately with an error. - wxMutexError TryLock(); - // Unlock the mutex. - wxMutexError Unlock(); - - // Returns true if the mutex is locked. - bool IsLocked() const { return (m_locked > 0); } + // constructor & destructor + wxMutex(); + ~wxMutex(); + + // Lock the mutex. + wxMutexError Lock(); + // Try to lock the mutex: if it can't, returns immediately with an error. + wxMutexError TryLock(); + // Unlock the mutex. + wxMutexError Unlock(); + + // Returns true if the mutex is locked. + 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 *m_internal; + + friend class wxConditionInternal; +}; + +// a helper class which locks the mutex in the ctor and unlocks it in the dtor: +// this ensures that mutex is always unlocked, even if the function returns or +// throws an exception before it reaches the end +class WXDLLEXPORT wxMutexLocker +{ +public: + // lock the mutex in the ctor + wxMutexLocker(wxMutex& mutex) : 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; } + + // unlock the mutex in dtor + ~wxMutexLocker() + { if ( IsOk() ) m_mutex.Unlock(); } + +private: + // no assignment operator nor copy ctor + wxMutexLocker(const wxMutexLocker&); + wxMutexLocker& operator=(const wxMutexLocker&); + + bool m_isOk; + 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. +// +// NB: wxCriticalSection object does not allocate any memory in its ctor +// 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_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: + // ctor & dtor + WXCRITICAL_INLINE wxCriticalSection(); + WXCRITICAL_INLINE ~wxCriticalSection(); + + // enter the section (the same as locking a mutex) + WXCRITICAL_INLINE void Enter(); + // leave the critical section (same as unlocking a mutex) + WXCRITICAL_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; +#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: + inline wxCriticalSectionLocker(wxCriticalSection& critsect); + inline ~wxCriticalSectionLocker(); + +private: + // no assignment operator nor copy ctor + wxCriticalSectionLocker(const wxCriticalSectionLocker&); + wxCriticalSectionLocker& operator=(const wxCriticalSectionLocker&); - int m_locked; - wxMutexInternal *p_internal; + wxCriticalSection& m_critsect; }; -// --------------------------------------------------------------------------- -// Condition handler. -class wxConditionInternal; -class WXDLLEXPORT wxCondition { +// ---------------------------------------------------------------------------- +// wxCondition models a POSIX condition variable which allows one (or more) +// thread(s) to wait until some condition is fulfilled +// ---------------------------------------------------------------------------- + +class WXDLLEXPORT 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 WXDLLEXPORT wxSemaphoreInternal; +class WXDLLEXPORT 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 + wxSemaphore( int initialcount = 0, int maxcount = 0 ); + + // dtor is not virtual, don't use this class polymorphically + ~wxSemaphore(); + + // wait indefinitely, until the semaphore count goes beyond 0 + // and then decrement it and return (this method might have been called + // Acquire()) + void 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 as a timeout limit, returns TRUE if the semaphore + // was acquired and FALSE if the timeout has ellapsed + bool Wait( unsigned long timeout_millis ); + + // increments the semaphore count and signals one of the waiting threads + void Post(); + +private: + wxSemaphoreInternal *m_internal; +}; + +// ---------------------------------------------------------------------------- +// wxThread: class encpasulating a thread of execution +// ---------------------------------------------------------------------------- + +// 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. + +// 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) + +// 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 + class wxThreadInternal; -class WXDLLEXPORT wxThread { +class WXDLLEXPORT wxThread +{ public: - // constructor & destructor. - wxThread(); - virtual ~wxThread(); + // 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(); - // Create a new thread, this method should check there is only one thread - // running by object. - wxThreadError Create(); + // 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); - // Destroys the thread immediately if the defer flag isn't true. - wxThreadError Destroy(); + // 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(); - // Pause a running thread - wxThreadError Pause(); + // 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(); - // Resume a paused thread - wxThreadError Resume(); + // 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); - // Switches on the defer flag. - void DeferDestroy(bool on); + // constructor only creates the C++ thread object and doesn't create (or + // start) the real thread + wxThread(wxThreadKind kind = wxTHREAD_DETACHED); - // Waits for the termination of the thread. - void *Join(); + // 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 - // 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; + // 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) - // Get the thread ID - unsigned long GetID() const; + wxThreadError Create(unsigned int stackSize = 0); - // 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 the main thread (aka the GUI thread). - static bool IsMain(); + // 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(); - // Called when thread exits. - virtual void OnExit(); + // 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(); - // Returns the wxThread object which corresponds to the ID. - static wxThread *GetThreadFromID(unsigned long id); protected: - // In case, the DIFFER flag is true, enables another thread to kill this one. - void TestDestroy(); - // Exits from the current thread. - void Exit(void *status = NULL); -private: - // Entry point for the thread. - virtual void *Entry() = 0; + // 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 - can be called only from this thread + void Exit(ExitCode exitcode = 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; - wxThreadInternal *p_internal; + // the (platform-dependent) thread class implementation + wxThreadInternal *m_internal; + + // protects access to any methods of wxThreadInternal object + wxCriticalSection m_critsect; + + // true if the thread is detached, false if it is joinable + bool m_isDetached; }; -// --------------------------------------------------------------------------- -// Global variables +// ---------------------------------------------------------------------------- +// Automatic initialization +// ---------------------------------------------------------------------------- // GUI mutex handling. void WXDLLEXPORT wxMutexGuiEnter(); void WXDLLEXPORT wxMutexGuiLeave(); -#endif +// 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 +class WXDLLEXPORT wxMutexGuiLocker +{ +public: + wxMutexGuiLocker() { wxMutexGuiEnter(); } + ~wxMutexGuiLocker() { wxMutexGuiLeave(); } +}; + +// ----------------------------------------------------------------------------- +// implementation only until the end of file +// ----------------------------------------------------------------------------- + +#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 + 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(); +#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() { } + 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__ +