always use wxString::operator[](size_t) - wxWin doesn't compile without it anyhow

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

diff --git a/include/wx/thread.h b/include/wx/thread.h
index 9700b4ddfd7214b4df86930347d520cba6270e9f..c47aca344955d9bd717e52dad4c1e72afaa4e62b 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


@@ -12,62 +13,188 @@
 #ifndef __THREADH__
 #define __THREADH__
 
 #ifndef __THREADH__
 #define __THREADH__
 

+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+// get the value of wxUSE_THREADS configuration flag
+#include "wx/setup.h"
+
+#if wxUSE_THREADS
+/* otherwise we get undefined references for non-thread case (KB)*/

 #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

 
 

-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
+#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;
 
 } 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;
 
 } 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 wxMutexInternal;

-class WXDLLEXPORT wxMutex {
+class WXDLLEXPORT wxMutex
+{

 public:
 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:
 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
+#if defined(__WXMSW__) || defined(__WXPM__)
+    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)
+    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 defined(__WXMSW__) || defined(__WXPM__)
+    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.
 // Condition handler.

+// ----------------------------------------------------------------------------
+

 class wxConditionInternal;
 class wxConditionInternal;

-class WXDLLEXPORT wxCondition {
+class WXDLLEXPORT wxCondition
+{

 public:
   // constructor & destructor
   wxCondition();
 public:
   // constructor & destructor
   wxCondition();


@@ -81,78 +208,205 @@ public:
   void Signal();
   // Broadcasts to all "Waiters".
   void Broadcast();
   void Signal();
   // Broadcasts to all "Waiters".
   void Broadcast();

+

 private:
   wxConditionInternal *p_internal;
 };
 
 private:
   wxConditionInternal *p_internal;
 };
 

-// ---------------------------------------------------------------------------
+// ----------------------------------------------------------------------------

 // Thread management class
 // 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 wxThreadInternal;

-class WXDLLEXPORT wxThread {
+class WXDLLEXPORT wxThread
+{

 public:
 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();
+
+        // 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();

 
 

-  // Create a new thread, this method should check there is only one thread
-  // running by object.
-  wxThreadError Create();
+        // 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);

 
 

-  // Destroys the thread immediately if the defer flag isn't true.
-  wxThreadError Destroy();
+    // default constructor
+    wxThread();

 
 

-  // Pause a running thread
-  wxThreadError Pause();
+    // function that change the thread state
+        // create a new thread - call Run() to start it
+    wxThreadError Create();

 
 

-  // Resume a paused thread
-  wxThreadError Resume();
+        // 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();

 
 

-  // Switches on the defer flag.
-  void DeferDestroy(bool on);
+        // 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();

 
 

-  // Waits for the termination of the thread.
-  void *Join();
+        // 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();

 
 

-  // 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;
+        // pause a running thread
+    wxThreadError Pause();

 
 

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

 
 

-  // 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();
+    // 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);

 
 

-  // Called when thread exits.
-  virtual void OnExit();
+        // 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;
+
+    // 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:
 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();
+
+    // 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:
 
 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.
-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_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_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__) || 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();
+
+    // 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__