Non-blocking reading before timeout after keystroke

ChangeLog

@@ -1,3 +1,7 @@
+2020-11-02  Markus Gans  <guru.mail@muenster.de>
+	* Non-blocking reading before timeout after keystroke
+	* Every fourth event processing causes a terminal flush
+
 2020-11-01  Markus Gans  <guru.mail@muenster.de>
 	* Now FINAL CUT queues keyboard and mouse input to speed up 
 	  the processing of widget events

examples/hello.cpp

@@ -28,6 +28,9 @@ int main (int argc, char* argv[])
   // Create the application object
   finalcut::FApplication app{argc, argv};
 
+  // Enable the non-blocking reading mode
+  //app.setNonBlockingRead();
+
   // Create a simple dialog box
   finalcut::FMessageBox mbox{&app};
   mbox.setText("Hello world");

src/fapplication.cpp

@@ -73,7 +73,7 @@ FMouseControl* FApplication::mouse           {nullptr};  // mouse control
 int            FApplication::loop_level      {0};        // event loop level
 int            FApplication::quit_code       {EXIT_SUCCESS};
 bool           FApplication::quit_now        {false};
-uInt64         FApplication::next_event_wait {5000};     // preset to 5 ms (200 Hz)
+uInt64         FApplication::next_event_wait {5000};     // 5 ms (200 Hz)
 struct timeval FApplication::time_last_event {};
 
 
@@ -693,7 +693,7 @@ void FApplication::escapeKeyPressed() const
 }
 
 //----------------------------------------------------------------------
-void FApplication::mouseTracking()
+void FApplication::mouseTracking() const
 {
   performMouseAction();
 }
@@ -1231,6 +1231,16 @@ void FApplication::sendWheelEvent ( const FMouseData& md
   }
 }
 
+//----------------------------------------------------------------------
+inline void FApplication::flushTerminal()
+{
+  if ( flush_count == 0 || flush_count % 4 != 0 )
+    return;
+
+  flush();
+  flush_count = 0;
+}
+
 //----------------------------------------------------------------------
 FWidget* FApplication::processParameters (const int& argc, char* argv[])
 {
@@ -1312,7 +1322,8 @@ bool FApplication::processNextEvent()
     processResizeEvent();
     processCloseWidget();
     processTerminalUpdate();  // after terminal changes
-    flush();
+    flushTerminal();
+    flush_count++;
     processLogger();
   }
 

src/fkeyboard.cpp

@@ -46,8 +46,10 @@ namespace finalcut
 {
 
 // static class attributes
-uInt64 FKeyboard::read_blocking_time{100000};  // preset to 100 ms (10 Hz)
+uInt64 FKeyboard::key_timeout{100000};             // 100 ms  (10 Hz)
-uInt64 FKeyboard::key_timeout{100000};         // preset to 100 ms (10 Hz)
+uInt64 FKeyboard::read_blocking_time{100000};      // 100 ms  (10 Hz)
+uInt64 FKeyboard::read_blocking_time_short{5000};  //   5 ms (200 Hz)
+bool   FKeyboard::non_blocking_input_support{true};
 struct timeval FKeyboard::time_keypressed{};
 
 #if defined(__linux__)
@@ -163,7 +165,7 @@ bool FKeyboard::isKeyPressed (uInt64 blocking_time)
   tv.tv_sec = tv.tv_usec = 0;  // Non-blocking input
 
   if ( blocking_time > 0
-     && term_detection->hasNonBlockingInputSupport()
+     && non_blocking_input_support
      && select(stdin_no + 1, &ifds, nullptr, nullptr, &tv) > 0
      && FD_ISSET(stdin_no, &ifds) )
   {
@@ -172,7 +174,10 @@ bool FKeyboard::isKeyPressed (uInt64 blocking_time)
     tv.tv_sec = 0;
   }
 
-  tv.tv_usec = suseconds_t(blocking_time);  // preset to 100 ms
+  if ( isKeypressTimeout() || ! non_blocking_input_support )
+    tv.tv_usec = suseconds_t(blocking_time);
+  else
+    tv.tv_usec = suseconds_t(read_blocking_time_short);
 
   if ( ! has_pending_input
     && select(stdin_no + 1, &ifds, nullptr, nullptr, &tv) > 0

src/ftermdetection.cpp

@@ -60,7 +60,7 @@ FKeyboard*                    FTermDetection::keyboard{nullptr};
 char                          FTermDetection::termtype[256]{};
 char                          FTermDetection::ttytypename[256]{};
 bool                          FTermDetection::decscusr_support{};
-bool                          FTermDetection::non_blocking_input_support{};
+
 bool                          FTermDetection::terminal_detection{};
 bool                          FTermDetection::color256{};
 const FString*                FTermDetection::answer_back{nullptr};
@@ -84,7 +84,6 @@ FTermDetection::FTermDetection()
 {
   // Preset to true
   terminal_detection = true;
-  non_blocking_input_support = true;
 
   // Preset to false
   decscusr_support = false;
@@ -411,8 +410,9 @@ void FTermDetection::detectTerminal()
 #if defined(__CYGWIN__)
   const auto& termfilename = fterm_data->getTermFileName();
 
+  // Fixes problem with mouse input
   if ( std::strncmp(termfilename, "/dev/cons", 9) == 0 )
-    non_blocking_input_support = false;  // Fixes problem with mouse input
+    FKeyboard::setNonBlockingInputSupport(false);
 #endif
 }
 

src/fvterm.cpp

@@ -217,7 +217,10 @@ void FVTerm::setNonBlockingRead (bool enable)
     termfilename[0] = '\0';
 
   if ( std::strncmp(termfilename, "/dev/cons", 9) == 0 )
+  {
+    FKeyboard::setNonBlockingInputSupport(false);
     return;
+  }
 #endif
 
   uInt64 blocking_time = (enable) ? 5000 : 100000;  // 5 or 100 ms

src/include/final/fapplication.h

@@ -182,7 +182,7 @@ class FApplication : public FWidget
     void                  keyPressed();
     void                  keyReleased() const;
     void                  escapeKeyPressed() const;
-    void                  mouseTracking();
+    void                  mouseTracking() const;
     void                  performKeyboardAction();
     void                  performMouseAction() const;
     void                  mouseEvent (const FMouseData&);
@@ -222,6 +222,7 @@ class FApplication : public FWidget
     void                  sendWheelEvent ( const FMouseData&
                                          , const FPoint&
                                          , const FPoint& ) const;
+    void                  flushTerminal();
     static FWidget*       processParameters (const int&, char*[]);
     void                  processResizeEvent() const;
     void                  processCloseWidget();
@@ -239,6 +240,7 @@ class FApplication : public FWidget
     std::streambuf*       default_clog_rdbuf{std::clog.rdbuf()};
     FWidget*              clicked_widget{};
     FEventQueue           event_queue{};
+    int                   flush_count{0};
     static uInt64         next_event_wait;
     static timeval        time_last_event;
     static int            quit_code;

src/include/final/fkeyboard.h

@@ -119,6 +119,7 @@ class FKeyboard final
     void                  setTermcapMap (const T&);
     static void           setKeypressTimeout (const uInt64);
     static void           setReadBlockingTime (const uInt64);
+    static void           setNonBlockingInputSupport (bool);
     bool                  setNonBlockingInput (bool);
     bool                  setNonBlockingInput();
     bool                  unsetNonBlockingInput();
@@ -189,7 +190,9 @@ class FKeyboard final
     FTermDetection*       term_detection{nullptr};
     static timeval        time_keypressed;
     static uInt64         read_blocking_time;
+    static uInt64         read_blocking_time_short;
     static uInt64         key_timeout;
+    static bool           non_blocking_input_support;
     FKeyMapPtr            key_map{};
     std::queue<FKey>      fkey_queue{};
     FKey                  fkey{0};
@@ -244,6 +247,10 @@ inline void FKeyboard::setKeypressTimeout (const uInt64 timeout)
 inline void FKeyboard::setReadBlockingTime (const uInt64 blocking_time)
 { read_blocking_time = blocking_time; }
 
+//----------------------------------------------------------------------
+inline void FKeyboard::setNonBlockingInputSupport (bool enable)
+{ non_blocking_input_support = enable; }
+
 //----------------------------------------------------------------------
 inline bool FKeyboard::setNonBlockingInput()
 { return setNonBlockingInput(true); }

src/include/final/ftermdetection.h

@@ -128,7 +128,6 @@ class FTermDetection final
     static bool           isMltermTerminal();
     static bool           canDisplay256Colors();
     static bool           hasTerminalDetection();
-    static bool           hasNonBlockingInputSupport();
     static bool           hasSetCursorStyleSupport();
 
     // Mutators
@@ -204,7 +203,6 @@ class FTermDetection final
     static char           termtype[256];
     static char           ttytypename[256];
     static bool           decscusr_support;
-    static bool           non_blocking_input_support;
     static bool           terminal_detection;
     static bool           color256;
     static int            gnome_terminal_id;
@@ -279,10 +277,6 @@ inline const char* FTermDetection::getTermType_SecDA()
 inline bool FTermDetection::canDisplay256Colors()
 { return color256; }
 
-//----------------------------------------------------------------------
-inline bool FTermDetection::hasNonBlockingInputSupport()
-{ return non_blocking_input_support; }
-
 //----------------------------------------------------------------------
 inline bool FTermDetection::hasSetCursorStyleSupport()
 { return decscusr_support; }