// 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
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-#ifndef _WX_THREADH__
-#define _WX_THREADH__
+#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
-} wxThreadError;
-
-// defines the interval of priority.
-#define WXTHREAD_MIN_PRIORITY 0
-#define WXTHREAD_DEFAULT_PRIORITY 50
-#define WXTHREAD_MAX_PRIORITY 100
-
-// ---------------------------------------------------------------------------
-// Mutex handler
-class wxMutexInternal;
-class WXDLLEXPORT wxMutex {
+// you should consider wxMutexLocker whenever possible instead of directly
+// working with wxMutex class - it is safer
+class WXDLLEXPORT wxMutexInternal;
+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;
+ friend class wxCondition;
- int m_locked;
- wxMutexInternal *p_internal;
+ // no assignment operator nor copy ctor
+ wxMutex(const wxMutex&);
+ wxMutex& operator=(const wxMutex&);
+
+ int m_locked;
+ wxMutexInternal *m_internal;
};
-// ---------------------------------------------------------------------------
-// Condition handler.
+// 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&);
+
+ wxCriticalSection& m_critsect;
+};
+
+// ----------------------------------------------------------------------------
+// Condition variable: allows to block the thread execution until something
+// happens (== condition is signaled)
+// ----------------------------------------------------------------------------
+
class wxConditionInternal;
-class WXDLLEXPORT wxCondition {
+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 & destructor
+ wxCondition();
+ ~wxCondition();
+
+ // wait until the condition is signaled
+ // waits indefinitely.
+ void Wait();
+ // waits until a signal is raised or the timeout elapses
+ bool Wait(unsigned long sec, unsigned long nsec);
+
+ // signal the condition
+ // wakes up one (and only one) of the waiting threads
+ void Signal();
+ // wakes up all threads waiting onthis condition
+ void Broadcast();
+
private:
- wxConditionInternal *p_internal;
+ wxConditionInternal *m_internal;
};
-// ---------------------------------------------------------------------------
-// Thread management class
+// ----------------------------------------------------------------------------
+// Thread class
+// ----------------------------------------------------------------------------
+
+// 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)
+
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();
+
+ // 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();
+
+ // 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 - call Run() to start it
+ wxThreadError Create();
- // Create a new thread, this method should check there is only one thread
- // running by object.
- wxThreadError Create();
+ // 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();
- // Destroys the thread immediately if the defer flag isn't true.
- wxThreadError Destroy();
+ // 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);
- // Switches on the defer flag.
- void DeferDestroy(bool on);
+ // 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();
- // Waits for the termination of the thread.
- void *Join();
+ // 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();
- // 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;
+ // pause a running thread: as Delete(), this only works if the thread
+ // calls TestDestroy() regularly
+ wxThreadError Pause();
- // Get the thread ID
- unsigned long GetID() const;
+ // resume a paused thread
+ wxThreadError Resume();
- // Returns true if the thread is alive.
- bool IsAlive() const;
- // Returns true if the thread is the main thread (aka the GUI thread).
- static bool IsMain();
+ // 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
+#ifdef __VMS
+ unsigned long long GetId() const;
+#else
+ unsigned long GetId() const;
+#endif
+
+ // 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();
- // Called when thread exits.
- virtual void OnExit();
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.
-WXDLLEXPORT_DATA(extern wxMutex) wxMainMutex;
+// 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__
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