// 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
#define __THREADH__
#ifdef __GNUG__
-#pragma interface "thread.h"
+ #pragma interface "thread.h"
#endif
-#include "wx/object.h"
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+// get the value of wxUSE_THREADS configuration flag
#include "wx/setup.h"
-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
+#if wxUSE_THREADS
+
+// Windows headers define it
+#ifdef Yield
+ #undef Yield
+#endif
+
+#include "wx/module.h"
+
+// ----------------------------------------------------------------------------
+// constants
+// ----------------------------------------------------------------------------
+
+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
} 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
+typedef enum
+{
+ 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
+// defines the interval of priority
+#define WXTHREAD_MIN_PRIORITY 0u
+#define WXTHREAD_DEFAULT_PRIORITY 50u
+#define WXTHREAD_MAX_PRIORITY 100u
-// ---------------------------------------------------------------------------
-// Mutex handler
+// ----------------------------------------------------------------------------
+// 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.
+// ----------------------------------------------------------------------------
+
+// you should consider wxMutexLocker whenever possible instead of directly
+// working with wxMutex class - it is safer
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;
+ friend class wxCondition;
+
+ // no assignment operator nor copy ctor
+ wxMutex(const wxMutex&);
+ wxMutex& operator=(const wxMutex&);
+
+ int m_locked;
+ wxMutexInternal *p_internal;
+};
+
+// 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; }
- int m_locked;
- wxMutexInternal *p_internal;
+ // 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
+// ----------------------------------------------------------------------------
+
+// in order to avoid any overhead under !MSW make all wxCriticalSection class
+// functions inline - but this can't be done under MSW
+#ifdef __WXMSW__
+ class WXDLLEXPORT wxCriticalSectionInternal;
+ #define WXCRITICAL_INLINE
+#else // !MSW
+ #define WXCRITICAL_INLINE inline
+#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)
+ void WXCRITICAL_INLINE Enter();
+ // leave the critical section (same as unlocking a mutex)
+ void WXCRITICAL_INLINE Leave();
+
+private:
+ // no assignment operator nor copy ctor
+ wxCriticalSection(const wxCriticalSection&);
+ wxCriticalSection& operator=(const wxCriticalSection&);
+
+#ifdef __WXMSW__
+ wxCriticalSectionInternal *m_critsect;
+#else // !MSW
+ wxMutex m_mutex;
+#endif // MSW/!MSW
};
-// ---------------------------------------------------------------------------
+// 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(); }
+
+private:
+ // no assignment operator nor copy ctor
+ wxCriticalSectionLocker(const wxCriticalSectionLocker&);
+ wxCriticalSectionLocker& operator=(const wxCriticalSectionLocker&);
+
+ wxCriticalSection& m_critsect;
+};
+
+// ----------------------------------------------------------------------------
// Condition handler.
+// ----------------------------------------------------------------------------
+
class wxConditionInternal;
-class WXDLLEXPORT wxCondition {
+class WXDLLEXPORT wxCondition
+{
public:
// constructor & destructor
wxCondition();
void Signal();
// Broadcasts to all "Waiters".
void Broadcast();
+
private:
wxConditionInternal *p_internal;
};
-// ---------------------------------------------------------------------------
+// ----------------------------------------------------------------------------
// Thread management class
+// ----------------------------------------------------------------------------
+
+// FIXME Thread termination model is still unclear. Delete() should probably
+// have a timeout after which the thread must be Kill()ed.
+
+// 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();
- // Create a new thread, this method should check there is only one thread
- // running by object.
- wxThreadError Create();
+ // Returns true if current thread is the main thread.
+ static bool IsMain();
- // Destroys the thread immediately if the defer flag isn't true.
- wxThreadError Destroy();
+ // Release the rest of our time slice leting the other threads run
+ static void Yield();
- // Pause a running thread
- wxThreadError Pause();
+ // 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);
- // Resume a paused thread
- wxThreadError Resume();
+ // default constructor
+ wxThread();
- // Switches on the defer flag.
- void DeferDestroy(bool on);
+ // function that change the thread state
+ // create a new thread - call Run() to start it
+ wxThreadError Create();
- // Waits for the termination of the thread.
- void *Join();
+ // 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();
- // 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;
+ // stops the thread if it's running and deletes the wxThread object
+ // freeing its memory. This function should also be called if the
+ // Create() or Run() fails to free memory (otherwise it will be done by
+ // the thread itself when it terminates). The return value is the
+ // thread exit code if the thread was gracefully terminated, 0 if it
+ // wasn't running and -1 if an error occured.
+ ExitCode Delete();
- // Get the thread ID
- unsigned long GetID() const;
+ // 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 thread was
+ // killed (i.e. no errors occured).
+ wxThreadError Kill();
- // 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();
+ // pause a running thread
+ wxThreadError Pause();
- // Called when thread exits.
- virtual void OnExit();
+ // 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;
+
+ // Get the thread ID - a platform dependent number which uniquely
+ // identifies a thread inside a process
+ unsigned long GetID() 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 { return IsAlive() && !IsRunning(); }
+
+ // 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() { }
- // 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() const;
+
+ // exits from the current thread - can be called only from this thread
+ void Exit(void *exitcode = 0);
+
+ // destructor is private - user code can't delete thread objects, they will
+ // auto-delete themselves (and thus must be always allocated on the heap).
+ // Use Delete() or Kill() instead.
+ //
+ // NB: derived classes dtors shouldn't be public neither!
+ virtual ~wxThread();
+
+ // 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 *p_internal;
+
+ // protects access to any methods of wxThreadInternal object
+ wxCriticalSection m_critsect;
};
-// ---------------------------------------------------------------------------
-// Global variables
+// ----------------------------------------------------------------------------
+// Automatic initialization
+// ----------------------------------------------------------------------------
// GUI mutex handling.
void WXDLLEXPORT wxMutexGuiEnter();
void WXDLLEXPORT wxMutexGuiLeave();
-#endif
+#else // !wxUSE_THREADS
+
+// no thread support
+inline void WXDLLEXPORT wxMutexGuiEnter() { }
+inline void WXDLLEXPORT wxMutexGuiLeave() { }
+
+#endif // wxUSE_THREADS
+
+// automatically unlock GUI mutex in dtor
+class WXDLLEXPORT wxMutexGuiLocker
+{
+public:
+ wxMutexGuiLocker() { wxMutexGuiEnter(); }
+ ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
+};
+
+// -----------------------------------------------------------------------------
+// implementation only until the end of file
+// -----------------------------------------------------------------------------
+#ifdef wxUSE_THREADS
+#ifdef __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();
+#else // !MSW
+ // 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 // wxUSE_THREADS
+
+#endif // __THREADH__
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