Trying to hide evidence of my negative programming skills...

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

diff --git a/include/wx/thread.h b/include/wx/thread.h
index 1041ed5db740b0ff6860475effc9779193a3cd19..d4af63db350620da9e63286c6637b11a02da27c6 100644 (file)
--- a/include/wx/thread.h
+++ b/include/wx/thread.h
@@ -2,7 +2,8 @@
 // Name:        thread.h
 // Purpose:     Thread API
 // Author:      Guilhem Lavaux
 // 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
 // Created:     04/13/98
 // RCS-ID:      $Id$
 // Copyright:   (c) Guilhem Lavaux


@@ -12,134 +13,511 @@
 #ifndef __THREADH__
 #define __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__
 #ifdef __GNUG__

-#pragma interface "thread.h"
+    #pragma interface "thread.h"

 #endif
 
 #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
-} 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:
 public:

-  // constructor & destructor 
-  wxMutex(void);
-  ~wxMutex(void);
-
-  // Lock the mutex.
-  wxMutexError Lock(void);
-  // Try to lock the mutex: if it can't, returns immediately with an error.
-  wxMutexError TryLock(void);
-  // Unlock the mutex.
-  wxMutexError Unlock(void);
-
-  // Returns true if the mutex is locked.
-  bool IsLocked(void) { 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:
 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 wxConditionInternal;

-class WXDLLEXPORT wxCondition {
+class WXDLLEXPORT wxCondition
+{

 public:
 public:

-  // constructor & destructor
-  wxCondition(void);
-  ~wxCondition(void);
-
-  // Waits undefinitely.
-  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(void);
-  // Broadcasts to all "Waiters".
-  void Broadcast(void);
+    // 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:
 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 wxThreadInternal;

-class WXDLLEXPORT wxThread {
+class WXDLLEXPORT wxThread
+{

 public:
 public:

-  // constructor & destructor.
-  wxThread(void);
-  virtual ~wxThread(void);
+    // 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(void);
+        // 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 flag DIFFER isn't true.
-  wxThreadError Destroy(void);
+        // 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 DIFFER 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(void);
+        // 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(void);
+        // pause a running thread: as Delete(), this only works if the thread
+        // calls TestDestroy() regularly
+    wxThreadError Pause();

 
 

-  // Get the thread ID
-  unsigned long GetID(void);
+        // resume a paused thread
+    wxThreadError Resume();

 
 

-  // Returns true if the thread is alive.
-  bool IsAlive(void);
-  // Returns true if the thread is the main thread (aka the GUI thread).
-  static bool IsMain(void);
+    // 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
+    unsigned long 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() { }
+
+    // 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(void);

 protected:
 protected:

-  // In case, the DIFFER flag is true, enables another thread to kill this one.
-  void TestDestroy(void);
-  // Exits from the current thread.
-  void Exit(void *status = NULL);
-private:
-  // Entry point for the thread.
-  virtual void *Entry(void) = 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:
 
 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__