A few tweaks and cleanups

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

diff --git a/include/wx/thread.h b/include/wx/thread.h
index af59d0db305888bc5cb0537e53e77fcc87344e18..60f5c7c5c44b7f4fdf2c71252a438817fb4b2442 100644 (file)
--- a/include/wx/thread.h
+++ b/include/wx/thread.h
@@ -21,7 +21,8 @@
 #include "wx/setup.h"
 
 #if wxUSE_THREADS
 #include "wx/setup.h"
 
 #if wxUSE_THREADS

-/* otherwise we get undefined references for non-thread case (KB)*/
+
+// only for wxUSE_THREADS - otherwise we'd get undefined symbols

 #ifdef __GNUG__
     #pragma interface "thread.h"
 #endif
 #ifdef __GNUG__
     #pragma interface "thread.h"
 #endif


@@ -37,28 +38,38 @@
 // constants
 // ----------------------------------------------------------------------------
 
 // constants
 // ----------------------------------------------------------------------------
 

-typedef enum
+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
-} wxMutexError;
-
-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
+};
+
+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_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;
+    wxTHREAD_DETACHED,
+    wxTHREAD_JOINABLE
+};

 
 // defines the interval of priority
 
 // defines the interval of priority

-#define WXTHREAD_MIN_PRIORITY     0u
-#define WXTHREAD_DEFAULT_PRIORITY 50u
-#define WXTHREAD_MAX_PRIORITY     100u
+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
 
 // ----------------------------------------------------------------------------
 // A mutex object is a synchronization object whose state is set to signaled


@@ -69,6 +80,7 @@ typedef 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
 {


@@ -88,14 +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;
     // no assignment operator nor copy ctor
     wxMutex(const wxMutex&);
     wxMutex& operator=(const wxMutex&);
 
     int m_locked;

-    wxMutexInternal *p_internal;
+    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:


@@ -129,21 +141,24 @@ private:
 // 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
 // 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
+// mutexes.
+//
+// NB: wxCriticalSection object does not allocate any memory in its ctor
+//     which makes it possible to have static globals of this class

 // ----------------------------------------------------------------------------
 
 // ----------------------------------------------------------------------------
 

-// in order to avoid any overhead under !MSW make all wxCriticalSection class
-// functions inline - but this can't be done under MSW
-#if defined(__WXMSW__)
-    class WXDLLEXPORT wxCriticalSectionInternal;
-    #define WXCRITICAL_INLINE
-#elif defined(__WXMAC__)
-    class WXDLLEXPORT wxCriticalSectionInternal;
-    #define WXCRITICAL_INLINE
-#elif defined(__WXPM__)
-    #define WXCRITICAL_INLINE
-#else // !MSW && !PM
+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 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
 #endif // MSW/!MSW
 
 // you should consider wxCriticalSectionLocker whenever possible instead of


@@ -165,11 +180,18 @@ private:
     wxCriticalSection(const wxCriticalSection&);
     wxCriticalSection& operator=(const wxCriticalSection&);
 
     wxCriticalSection(const wxCriticalSection&);
     wxCriticalSection& operator=(const wxCriticalSection&);
 

-#if defined(__WXMSW__) || defined(__WXMAC__)
-    wxCriticalSectionInternal *m_critsect;
-#else // !MSW
+#if wxCRITSECT_IS_MUTEX

     wxMutex m_mutex;
     wxMutex m_mutex;

-#endif // MSW/!MSW
+#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
 };
 
 // keep your preprocessor name space clean


@@ -192,40 +214,115 @@ private:
 };
 
 // ----------------------------------------------------------------------------
 };
 
 // ----------------------------------------------------------------------------

-// Condition handler.
+// 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();
-  ~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:
 
 private:

-  wxConditionInternal *p_internal;
+    wxConditionInternal *m_internal;

 };
 
 // ----------------------------------------------------------------------------
 };
 
 // ----------------------------------------------------------------------------

-// Thread management class
+// wxSemaphore: a counter limiting the number of threads concurrently accessing
+//              a shared resource

 // ----------------------------------------------------------------------------
 
 // ----------------------------------------------------------------------------
 

-// FIXME Thread termination model is still unclear. Delete() should probably
-//       have a timeout after which the thread must be Kill()ed.
+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)
 
 // 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 wxThreadInternal;
 class WXDLLEXPORT wxThread
 {


@@ -252,34 +349,75 @@ public:
         // NB: at least under MSW worker threads can not call ::wxSleep()!
     static void Sleep(unsigned long milliseconds);
 
         // NB: at least under MSW worker threads can not call ::wxSleep()!
     static void Sleep(unsigned long milliseconds);
 

-    // default constructor
-    wxThread();
+        // 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();
+
+        // 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
+        // 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

 
 

-    // function that change the thread state
-        // 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)

 
 

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

         // shouldn't suppose that it starts after (or before) Run() returns.
     wxThreadError Run();
 
         // shouldn't suppose that it starts after (or before) Run() returns.
     wxThreadError Run();
 

-        // 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();
+        // 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
 
         // 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).
+        // 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();
 
     wxThreadError Kill();
 

-        // pause a running thread
+        // pause a running thread: as Delete(), this only works if the thread
+        // calls TestDestroy() regularly

     wxThreadError Pause();
 
         // resume a paused thread
     wxThreadError Pause();
 
         // resume a paused thread


@@ -294,10 +432,6 @@ public:
         // Get the current priority.
     unsigned int GetPriority() const;
 
         // 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;
     // thread status inquiries
         // Returns true if the thread is alive: i.e. running or suspended
     bool IsAlive() const;


@@ -306,11 +440,22 @@ public:
         // Returns true if the thread is suspended
     bool IsPaused() 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() { }
 
     // 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();
+

 protected:
     // 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
 protected:
     // 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


@@ -318,14 +463,7 @@ protected:
     bool TestDestroy();
 
     // exits from the current thread - can be called only from this thread
     bool TestDestroy();
 
     // 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();
+    void Exit(ExitCode exitcode = 0);

 
     // entry point for the thread - called by Run() and executes in the context
     // of this thread.
 
     // entry point for the thread - called by Run() and executes in the context
     // of this thread.


@@ -339,10 +477,13 @@ private:
     friend class wxThreadInternal;
 
     // the (platform-dependent) thread class implementation
     friend class wxThreadInternal;
 
     // the (platform-dependent) thread class implementation

-    wxThreadInternal *p_internal;
+    wxThreadInternal *m_internal;

 
     // protects access to any methods of wxThreadInternal object
     wxCriticalSection m_critsect;
 
     // 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;

 };
 
 // ----------------------------------------------------------------------------
 };
 
 // ----------------------------------------------------------------------------


@@ -355,9 +496,10 @@ void WXDLLEXPORT wxMutexGuiLeave();
 
 // macros for entering/leaving critical sections which may be used without
 // having to take them inside "#if wxUSE_THREADS"
 
 // 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_LOCKER(name, cs)  wxCriticalSectionLocker name(*cs)
+#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
 
 
 #else // !wxUSE_THREADS
 


@@ -371,6 +513,7 @@ inline void WXDLLEXPORT wxMutexGuiLeave() { }
 // having to take them inside "#if wxUSE_THREADS"
 #define wxENTER_CRIT_SECT(cs)
 #define wxLEAVE_CRIT_SECT(cs)
 // 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
 #define wxCRIT_SECT_LOCKER(name, cs)
 
 #endif // wxUSE_THREADS


@@ -405,7 +548,7 @@ public:
     // wxApp then should block all "dangerous" messages
     extern bool WXDLLEXPORT wxIsWaitingForThread();
 #elif defined(__WXMAC__)
     // 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();
 
     // returns TRUE if the main thread has GUI lock
     extern bool WXDLLEXPORT wxGuiOwnedByMainThread();


@@ -416,6 +559,13 @@ public:
     // return TRUE if the main thread is waiting for some other to terminate:
     // wxApp then should block all "dangerous" messages
     extern bool WXDLLEXPORT wxIsWaitingForThread();
     // 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
 #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


@@ -448,3 +598,4 @@ public:
 #endif // wxUSE_THREADS
 
 #endif // __THREADH__
 #endif // wxUSE_THREADS
 
 #endif // __THREADH__

+