Consolidate timeout handling across platforms (#379)

Add Fl_Timeout class

Move platform independent code of Fl::wait() to main part

- basic timeout handling
- Fl::run_checks()
- Fl::run_idle()
- Fl::idle()
- waiting time calculation (next timeout)
- remove platform dependent "screen driver" stuff

6 files changed, 14 insertions, 456 deletions

diff --git a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
index dcd5c4f57..7dd6fc14a 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
+++ b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
@@ -2,7 +2,7 @@
 // Definition of Apple Cocoa Screen interface
 // for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2018 by Bill Spitzak and others.
+// Copyright 2010-2022 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -80,11 +80,6 @@ public:
   virtual void grab(Fl_Window* win);
   // --- global colors
   virtual void get_system_colors();
-  // --- global timers
-  virtual void add_timeout(double time, Fl_Timeout_Handler cb, void *argp);
-  virtual void repeat_timeout(double time, Fl_Timeout_Handler cb, void *argp);
-  virtual int has_timeout(Fl_Timeout_Handler cb, void *argp);
-  virtual void remove_timeout(Fl_Timeout_Handler cb, void *argp);
   virtual int has_marked_text() const;
   static void reset_marked_text();
   static void insertion_point_location(int x, int y, int height);
diff --git a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
index 1a36149e2..e213e5fd0 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
+++ b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
@@ -1,7 +1,7 @@
 //
 // Definition of Apple Cocoa Screen interface.
 //
-// Copyright 1998-2018 by Bill Spitzak and others.
+// Copyright 1998-2022 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -401,143 +401,3 @@ Fl_RGB_Image *Fl_Cocoa_Screen_Driver::read_win_rectangle(int X, int Y, int w, in
   rgb->alloc_array = 1;
   return rgb;
 }
-
-//
-// MacOS X timers
-//
-
-struct MacTimeout {
-  Fl_Timeout_Handler callback;
-  void* data;
-  CFRunLoopTimerRef timer;
-  char pending;
-  CFAbsoluteTime next_timeout; // scheduled time for this timer
-};
-static MacTimeout* mac_timers;
-static int mac_timer_alloc;
-static int mac_timer_used;
-static MacTimeout* current_timer;  // the timer that triggered its callback function
-
-static void realloc_timers()
-{
-  if (mac_timer_alloc == 0) {
-    mac_timer_alloc = 8;
-    fl_open_display(); // needed because the timer creates an event
-  }
-  mac_timer_alloc *= 2;
-  MacTimeout* new_timers = new MacTimeout[mac_timer_alloc];
-  memset(new_timers, 0, sizeof(MacTimeout)*mac_timer_alloc);
-  memcpy(new_timers, mac_timers, sizeof(MacTimeout) * mac_timer_used);
-  if (current_timer) {
-    MacTimeout* newCurrent = new_timers + (current_timer - mac_timers);
-    current_timer = newCurrent;
-  }
-  MacTimeout* delete_me = mac_timers;
-  mac_timers = new_timers;
-  delete [] delete_me;
-}
-
-static void delete_timer(MacTimeout& t)
-{
-  if (t.timer) {
-    CFRunLoopRemoveTimer(CFRunLoopGetCurrent(),
-                         t.timer,
-                         kCFRunLoopDefaultMode);
-    CFRelease(t.timer);
-    memset(&t, 0, sizeof(MacTimeout));
-  }
-}
-
-static void do_timer(CFRunLoopTimerRef timer, void* data)
-{
-  fl_lock_function();
-  fl_intptr_t timerId = (fl_intptr_t)data;
-  current_timer = &mac_timers[timerId];
-  current_timer->pending = 0;
-  (current_timer->callback)(current_timer->data);
-  if (current_timer && current_timer->pending == 0)
-    delete_timer(*current_timer);
-  current_timer = NULL;
-
-  Fl_Cocoa_Screen_Driver::breakMacEventLoop();
-  fl_unlock_function();
-}
-
-void Fl_Cocoa_Screen_Driver::add_timeout(double time, Fl_Timeout_Handler cb, void* data)
-{
-  // always create a new timer entry
-  fl_intptr_t timer_id = -1;
-  // find an empty slot in the timer array
-  for (int i = 0; i < mac_timer_used; ++i) {
-    if ( !mac_timers[i].timer ) {
-      timer_id = i;
-      break;
-    }
-  }
-  // if there was no empty slot, append a new timer
-  if (timer_id == -1) {
-    // make space if needed
-    if (mac_timer_used == mac_timer_alloc) {
-      realloc_timers();
-    }
-    timer_id = mac_timer_used++;
-  }
-  // now install a brand new timer
-  MacTimeout& t = mac_timers[timer_id];
-  CFRunLoopTimerContext context = {0, (void*)timer_id, NULL,NULL,NULL};
-  CFRunLoopTimerRef timerRef = CFRunLoopTimerCreate(kCFAllocatorDefault,
-                                                    CFAbsoluteTimeGetCurrent() + time,
-                                                    1E30,
-                                                    0,
-                                                    0,
-                                                    do_timer,
-                                                    &context
-                                                    );
-  if (timerRef) {
-    CFRunLoopAddTimer(CFRunLoopGetCurrent(),
-                      timerRef,
-                      kCFRunLoopDefaultMode);
-    t.callback = cb;
-    t.data     = data;
-    t.timer    = timerRef;
-    t.pending  = 1;
-    t.next_timeout = CFRunLoopTimerGetNextFireDate(timerRef);
-  }
-}
-
-void Fl_Cocoa_Screen_Driver::repeat_timeout(double time, Fl_Timeout_Handler cb, void* data)
-{
-  if (!current_timer) {
-    add_timeout(time, cb, data);
-    return;
-  }
-  // k = how many times 'time' seconds after the last scheduled timeout until the future
-  double k = ceil( (CFAbsoluteTimeGetCurrent() - current_timer->next_timeout) / time);
-  if (k < 1) k = 1;
-  current_timer->next_timeout += k * time;
-  CFRunLoopTimerSetNextFireDate(current_timer->timer, current_timer->next_timeout );
-  current_timer->callback = cb;
-  current_timer->data = data;
-  current_timer->pending = 1;
-}
-
-int Fl_Cocoa_Screen_Driver::has_timeout(Fl_Timeout_Handler cb, void* data)
-{
-  for (int i = 0; i < mac_timer_used; ++i) {
-    MacTimeout& t = mac_timers[i];
-    if (t.callback == cb  &&  t.data == data && t.pending) {
-      return 1;
-    }
-  }
-  return 0;
-}
-
-void Fl_Cocoa_Screen_Driver::remove_timeout(Fl_Timeout_Handler cb, void* data)
-{
-  for (int i = 0; i < mac_timer_used; ++i) {
-    MacTimeout& t = mac_timers[i];
-    if (t.callback == cb  && ( t.data == data || data == NULL)) {
-      delete_timer(t);
-    }
-  }
-}
diff --git a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
index 9bd8485a3..c621f7e5e 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
+++ b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
@@ -1,8 +1,7 @@
 //
-// Definition of Windows screen interface
-// for the Fast Light Tool Kit (FLTK).
+// Windows screen interface for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2018 by Bill Spitzak and others.
+// Copyright 2010-2022 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -67,11 +66,6 @@ public:
   virtual void grab(Fl_Window* win);
   // --- global colors
   virtual void get_system_colors();
-  // --- global timers
-  virtual void add_timeout(double time, Fl_Timeout_Handler cb, void *argp);
-  virtual void repeat_timeout(double time, Fl_Timeout_Handler cb, void *argp);
-  virtual int has_timeout(Fl_Timeout_Handler cb, void *argp);
-  virtual void remove_timeout(Fl_Timeout_Handler cb, void *argp);
   virtual int dnd(int unused);
   virtual int compose(int &del);
   virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h, Fl_Window *win, bool may_capture_subwins, bool *did_capture_subwins);
diff --git a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
index 5747f16a4..489e7fe8d 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
+++ b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
@@ -1,7 +1,7 @@
 //
 // Windows screen interface for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2018 by Bill Spitzak and others.
+// Copyright 1998-2022 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -328,149 +328,6 @@ void Fl_WinAPI_Screen_Driver::get_system_colors()
 }
 
 
-// ---- timers
-
-
-struct Win32Timer
-{
-  UINT_PTR handle;
-  Fl_Timeout_Handler callback;
-  void *data;
-};
-static Win32Timer* win32_timers;
-static int win32_timer_alloc;
-static int win32_timer_used;
-static HWND s_TimerWnd;
-
-
-static void realloc_timers()
-{
-  if (win32_timer_alloc == 0) {
-    win32_timer_alloc = 8;
-  }
-  win32_timer_alloc *= 2;
-  Win32Timer* new_timers = new Win32Timer[win32_timer_alloc];
-  memset(new_timers, 0, sizeof(Win32Timer) * win32_timer_used);
-  memcpy(new_timers, win32_timers, sizeof(Win32Timer) * win32_timer_used);
-  Win32Timer* delete_me = win32_timers;
-  win32_timers = new_timers;
-  delete [] delete_me;
-}
-
-
-static void delete_timer(Win32Timer& t)
-{
-  KillTimer(s_TimerWnd, t.handle);
-  memset(&t, 0, sizeof(Win32Timer));
-}
-
-
-static LRESULT CALLBACK s_TimerProc(HWND hwnd, UINT msg,
-                                    WPARAM wParam, LPARAM lParam)
-{
-  switch (msg) {
-    case WM_TIMER:
-    {
-      unsigned int id = (unsigned) (wParam - 1);
-      if (id < (unsigned int)win32_timer_used && win32_timers[id].handle) {
-        Fl_Timeout_Handler cb   = win32_timers[id].callback;
-        void*              data = win32_timers[id].data;
-        delete_timer(win32_timers[id]);
-        if (cb) {
-          (*cb)(data);
-        }
-      }
-    }
-      return 0;
-
-    default:
-      break;
-  }
-  return DefWindowProc(hwnd, msg, wParam, lParam);
-}
-
-
-void Fl_WinAPI_Screen_Driver::add_timeout(double time, Fl_Timeout_Handler cb, void* data)
-{
-  repeat_timeout(time, cb, data);
-}
-
-
-void Fl_WinAPI_Screen_Driver::repeat_timeout(double time, Fl_Timeout_Handler cb, void* data)
-{
-  int timer_id = -1;
-  for (int i = 0;  i < win32_timer_used;  ++i) {
-    if ( !win32_timers[i].handle ) {
-      timer_id = i;
-      break;
-    }
-  }
-  if (timer_id == -1) {
-    if (win32_timer_used == win32_timer_alloc) {
-      realloc_timers();
-    }
-    timer_id = win32_timer_used++;
-  }
-  unsigned int elapsed = (unsigned int)(time * 1000);
-
-  if ( !s_TimerWnd ) {
-    const char* timer_class = "FLTimer";
-    WNDCLASSEX wc;
-    memset(&wc, 0, sizeof(wc));
-    wc.cbSize = sizeof (wc);
-    wc.style = CS_CLASSDC;
-    wc.lpfnWndProc = (WNDPROC)s_TimerProc;
-    wc.hInstance = fl_display;
-    wc.lpszClassName = timer_class;
-    /*ATOM atom =*/ RegisterClassEx(&wc);
-    // create a zero size window to handle timer events
-    s_TimerWnd = CreateWindowEx(WS_EX_LEFT | WS_EX_TOOLWINDOW,
-                                timer_class, "",
-                                WS_POPUP,
-                                0, 0, 0, 0,
-                                NULL, NULL, fl_display, NULL);
-    // just in case this OS won't let us create a 0x0 size window:
-    if (!s_TimerWnd)
-      s_TimerWnd = CreateWindowEx(WS_EX_LEFT | WS_EX_TOOLWINDOW,
-                                  timer_class, "",
-                                  WS_POPUP,
-                                  0, 0, 1, 1,
-                                  NULL, NULL, fl_display, NULL);
-    ShowWindow(s_TimerWnd, SW_SHOWNOACTIVATE);
-  }
-
-  win32_timers[timer_id].callback = cb;
-  win32_timers[timer_id].data     = data;
-
-  win32_timers[timer_id].handle =
-  SetTimer(s_TimerWnd, timer_id + 1, elapsed, NULL);
-}
-
-
-int Fl_WinAPI_Screen_Driver::has_timeout(Fl_Timeout_Handler cb, void* data)
-{
-  for (int i = 0;  i < win32_timer_used;  ++i) {
-    Win32Timer& t = win32_timers[i];
-    if (t.handle  &&  t.callback == cb  &&  t.data == data) {
-      return 1;
-    }
-  }
-  return 0;
-}
-
-
-void Fl_WinAPI_Screen_Driver::remove_timeout(Fl_Timeout_Handler cb, void* data)
-{
-  int i;
-  for (i = 0;  i < win32_timer_used;  ++i) {
-    Win32Timer& t = win32_timers[i];
-    if (t.handle  &&  t.callback == cb  &&
-        (t.data == data  ||  data == NULL)) {
-      delete_timer(t);
-    }
-  }
-}
-
 int Fl_WinAPI_Screen_Driver::compose(int &del) {
   unsigned char ascii = (unsigned char)Fl::e_text[0];
   int condition = (Fl::e_state & (FL_ALT | FL_META)) && !(ascii & 128) ;
diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.H b/src/drivers/X11/Fl_X11_Screen_Driver.H
index 7d665dbb4..c8676f347 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.H
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.H
@@ -85,11 +85,6 @@ public:
   virtual int parse_color(const char* p, uchar& r, uchar& g, uchar& b);
   virtual void get_system_colors();
   virtual const char *get_system_scheme();
-  // --- global timers
-  virtual void add_timeout(double time, Fl_Timeout_Handler cb, void *argp);
-  virtual void repeat_timeout(double time, Fl_Timeout_Handler cb, void *argp);
-  virtual int has_timeout(Fl_Timeout_Handler cb, void *argp);
-  virtual void remove_timeout(Fl_Timeout_Handler cb, void *argp);
   virtual int dnd(int unused);
   virtual int compose(int &del);
   virtual void compose_reset();
diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.cxx b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
index beb30df83..3e7edf872 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
@@ -31,6 +31,8 @@
 #include <FL/filename.H>
 #include <sys/time.h>
 
+#include "../../Fl_Timeout.h"
+
 #if HAVE_XINERAMA
 #  include <X11/extensions/Xinerama.h>
 #endif
@@ -55,52 +57,6 @@ extern const char *fl_bg;
 extern const char *fl_bg2;
 // end of extern additions workaround
 
-//
-// X11 timers
-//
-
-
-////////////////////////////////////////////////////////////////////////
-// Timeouts are stored in a sorted list (*first_timeout), so only the
-// first one needs to be checked to see if any should be called.
-// Allocated, but unused (free) Timeout structs are stored in another
-// linked list (*free_timeout).
-
-struct Timeout {
-  double time;
-  void (*cb)(void*);
-  void* arg;
-  Timeout* next;
-};
-static Timeout* first_timeout, *free_timeout;
-
-// I avoid the overhead of getting the current time when we have no
-// timeouts by setting this flag instead of getting the time.
-// In this case calling elapse_timeouts() does nothing, but records
-// the current time, and the next call will actually elapse time.
-static char reset_clock = 1;
-
-static void elapse_timeouts() {
-  static struct timeval prevclock;
-  struct timeval newclock;
-  gettimeofday(&newclock, NULL);
-  double elapsed = newclock.tv_sec - prevclock.tv_sec +
-    (newclock.tv_usec - prevclock.tv_usec)/1000000.0;
-  prevclock.tv_sec = newclock.tv_sec;
-  prevclock.tv_usec = newclock.tv_usec;
-  if (reset_clock) {
-    reset_clock = 0;
-  } else if (elapsed > 0) {
-    for (Timeout* t = first_timeout; t; t = t->next) t->time -= elapsed;
-  }
-}
-
-
-// Continuously-adjusted error value, this is a number <= 0 for how late
-// we were at calling the last timeout. This appears to make repeat_timeout
-// very accurate even when processing takes a significant portion of the
-// time interval:
-static double missed_timeout_by;
 
 /**
  Creates a driver that manages all screen and display related calls.
@@ -411,39 +367,6 @@ void Fl_X11_Screen_Driver::flush()
 
 double Fl_X11_Screen_Driver::wait(double time_to_wait)
 {
-  static char in_idle;
-
-  if (first_timeout) {
-    elapse_timeouts();
-    Timeout *t;
-    while ((t = first_timeout)) {
-      if (t->time > 0) break;
-      // The first timeout in the array has expired.
-      missed_timeout_by = t->time;
-      // We must remove timeout from array before doing the callback:
-      void (*cb)(void*) = t->cb;
-      void *argp = t->arg;
-      first_timeout = t->next;
-      t->next = free_timeout;
-      free_timeout = t;
-      // Now it is safe for the callback to do add_timeout:
-      cb(argp);
-    }
-  } else {
-    reset_clock = 1; // we are not going to check the clock
-  }
-  Fl::run_checks();
-  if (Fl::idle) {
-    if (!in_idle) {
-      in_idle = 1;
-      Fl::idle();
-      in_idle = 0;
-    }
-    // the idle function may turn off idle, we can then wait:
-    if (Fl::idle) time_to_wait = 0.0;
-  }
-  if (first_timeout && first_timeout->time < time_to_wait)
-    time_to_wait = first_timeout->time;
   if (time_to_wait <= 0.0) {
     // do flush second so that the results of events are visible:
     int ret = this->poll_or_select_with_delay(0.0);
@@ -452,25 +375,20 @@ double Fl_X11_Screen_Driver::wait(double time_to_wait)
   } else {
     // do flush first so that user sees the display:
     Fl::flush();
-    if (Fl::idle && !in_idle) // 'idle' may have been set within flush()
+    if (Fl::idle) // 'idle' may have been set within flush()
       time_to_wait = 0.0;
-    else if (first_timeout && first_timeout->time < time_to_wait) {
-      // another timeout may have been queued within flush(), see STR #3188
-      time_to_wait = first_timeout->time >= 0.0 ? first_timeout->time : 0.0;
+    else {
+      Fl_Timeout::elapse_timeouts();
+      time_to_wait = Fl_Timeout::time_to_wait(time_to_wait);
     }
     return this->poll_or_select_with_delay(time_to_wait);
   }
 }
 
 
-int Fl_X11_Screen_Driver::ready()
-{
-  if (first_timeout) {
-    elapse_timeouts();
-    if (first_timeout->time <= 0) return 1;
-  } else {
-    reset_clock = 1;
-  }
+int Fl_X11_Screen_Driver::ready() {
+  Fl_Timeout::elapse_timeouts();
+  if (Fl_Timeout::time_to_wait(1.0) <= 0.0) return 1;
   return this->poll_or_select();
 }
 
@@ -598,67 +516,6 @@ const char *Fl_X11_Screen_Driver::get_system_scheme()
   return s;
 }
 
-// ######################   *FIXME*   ########################
-// ######################   *FIXME*   ########################
-// ######################   *FIXME*   ########################
-
-
-//
-// X11 timers
-//
-
-void Fl_X11_Screen_Driver::add_timeout(double time, Fl_Timeout_Handler cb, void *argp) {
-  elapse_timeouts();
-  missed_timeout_by = 0;
-  repeat_timeout(time, cb, argp);
-}
-
-void Fl_X11_Screen_Driver::repeat_timeout(double time, Fl_Timeout_Handler cb, void *argp) {
-  time += missed_timeout_by; if (time < -.05) time = 0;
-  Timeout* t = free_timeout;
-  if (t) {
-      free_timeout = t->next;
-  } else {
-      t = new Timeout;
-  }
-  t->time = time;
-  t->cb = cb;
-  t->arg = argp;
-  // insert-sort the new timeout:
-  Timeout** p = &first_timeout;
-  while (*p && (*p)->time <= time) p = &((*p)->next);
-  t->next = *p;
-  *p = t;
-}
-
-/**
-  Returns true if the timeout exists and has not been called yet.
-*/
-int Fl_X11_Screen_Driver::has_timeout(Fl_Timeout_Handler cb, void *argp) {
-  for (Timeout* t = first_timeout; t; t = t->next)
-    if (t->cb == cb && t->arg == argp) return 1;
-  return 0;
-}
-
-/**
-  Removes a timeout callback. It is harmless to remove a timeout
-  callback that no longer exists.
-
-  \note This version removes all matching timeouts, not just the first one.
-        This may change in the future.
-*/
-void Fl_X11_Screen_Driver::remove_timeout(Fl_Timeout_Handler cb, void *argp) {
-  for (Timeout** p = &first_timeout; *p;) {
-    Timeout* t = *p;
-    if (t->cb == cb && (t->arg == argp || !argp)) {
-      *p = t->next;
-      t->next = free_timeout;
-      free_timeout = t;
-    } else {
-      p = &(t->next);
-    }
-  }
-}
 
 int Fl_X11_Screen_Driver::compose(int& del) {
   int condition;