A few tweaks and cleanups

[wxWidgets.git] / include / wx / thread.h

diff --git a/include/wx/thread.h b/include/wx/thread.h
index d4af63db350620da9e63286c6637b11a02da27c6..60f5c7c5c44b7f4fdf2c71252a438817fb4b2442 100644 (file)
--- a/include/wx/thread.h
+++ b/include/wx/thread.h
@@ -80,6 +80,7 @@ enum
 
 // you should consider wxMutexLocker whenever possible instead of directly
 // working with wxMutex class - it is safer
 
 // 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 wxMutexInternal;
 class WXDLLEXPORT wxMutex
 {


@@ -99,14 +100,14 @@ public:
     bool IsLocked() const { return (m_locked > 0); }
 
 protected:
     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;
     // 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:
 };
 
 // a helper class which locks the mutex in the ctor and unlocks it in the dtor:


@@ -213,28 +214,53 @@ private:
 };
 
 // ----------------------------------------------------------------------------
 };
 
 // ----------------------------------------------------------------------------

-// 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
 {
 public:
 class WXDLLEXPORT 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();
 
     ~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();
     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();
     void Signal();

-        // wakes up all threads waiting onthis 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:
     void Broadcast();
 
 private:


@@ -242,7 +268,43 @@ private:
 };
 
 // ----------------------------------------------------------------------------
 };
 
 // ----------------------------------------------------------------------------

-// Thread 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)
 // ----------------------------------------------------------------------------
 
 // there are two different kinds of threads: joinable and detached (default)


@@ -254,6 +316,13 @@ private:
 //     created by the wxThread object while "main thread" is the thread created
 //     during the process initialization (a.k.a. the GUI 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 wxThreadInternal;
 class WXDLLEXPORT wxThread
 {


@@ -286,6 +355,11 @@ public:
         // Returns -1 if unknown, number of CPUs otherwise
     static int GetCPUCount();
 
         // Returns -1 if unknown, number of CPUs otherwise
     static int GetCPUCount();
 

+        // 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();
+

         // 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
         // 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


@@ -303,8 +377,11 @@ public:
     // from _another_ thread (typically the thread that created this one, e.g.
     // the main thread), not from the thread itself
 
     // 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 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)
+
+    wxThreadError Create(unsigned int stackSize = 0);

 
         // starts execution of the thread - from the moment Run() is called
         // the execution of wxThread::Entry() may start at any moment, caller
 
         // starts execution of the thread - from the moment Run() is called
         // the execution of wxThread::Entry() may start at any moment, caller


@@ -368,7 +445,7 @@ public:
 
     // Get the thread ID - a platform dependent number which uniquely
     // identifies a thread inside a process
 
     // Get the thread ID - a platform dependent number which uniquely
     // identifies a thread inside a process

-    unsigned long GetId() const;
+    wxThreadIdType GetId() const;

 
     // called when the thread exits - in the context of this thread
     //
 
     // called when the thread exits - in the context of this thread
     //


@@ -521,3 +598,4 @@ public:
 #endif // wxUSE_THREADS
 
 #endif // __THREADH__
 #endif // wxUSE_THREADS
 
 #endif // __THREADH__

+