// 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
{
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:
{
public:
// lock the mutex in the ctor
- wxMutexLocker(wxMutex& mutex) : m_mutex(mutex)
- { m_isOk = m_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
};
// ----------------------------------------------------------------------------
-// Condition variable: allows to block the thread execution until something
-// happens (== condition is signaled)
+// 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
{
+ DECLARE_NO_COPY_CLASS(wxCondition)
+
public:
- // constructor & destructor
- wxCondition();
+ // 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();
- // wait until the condition is signaled
- // waits indefinitely.
+ // 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();
- // 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
+ // 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();
- // wakes up all threads waiting on this condition
+
+ // 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:
};
// ----------------------------------------------------------------------------
-// Thread class
+// wxSemaphore: a counter limiting the number of threads concurrently accessing
+// 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
+ 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)
// wxApp then should block all "dangerous" messages
extern bool WXDLLEXPORT wxIsWaitingForThread();
#elif defined(__WXMAC__)
- extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
+ extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
// returns TRUE if the main thread has GUI lock
extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
extern bool WXDLLEXPORT wxIsWaitingForThread();
// implement wxCriticalSection using mutexes
- inline wxCriticalSection::wxCriticalSection() { }
+ inline wxCriticalSection::wxCriticalSection() : m_mutex() { }
inline wxCriticalSection::~wxCriticalSection() { }
inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
#endif // __THREADH__
-// vi:sts=4:sw=4:et
projects / wxWidgets.git / blobdiff