Change the way input is read

Before rp used xgrabkeyboard to read a key. Instead, the keyboard is
frozen when a top level key is read. Then when rp reads a key it first
sets the input focus to a suitable location such as key_window or
input_window, then thaws the keyboard and waits for a keypress. When a
key is pressed the keyboard is frozen again and the process repeats
until ratpoison is done reading input. At that point the keyboard is
thawed in a way that future keystrokes do not refreeze the keyboard.

4 files changed, 51 insertions, 29 deletions

diff --git a/src/actions.c b/src/actions.c
index 0de31ed..6bf53d3 100644
--- a/src/actions.c
+++ b/src/actions.c
@@ -1739,9 +1739,7 @@ read_frame (struct argspec *spec, struct sbuf *s,  struct cmdarg **arg)
       XSync (dpy, False);
 
       /* Read a key. */
-      XGrabKeyboard (dpy, current_screen()->key_window, False, GrabModeSync, GrabModeAsync, CurrentTime);
-      read_key (&c, &mod, keysym_buf, keysym_bufsize);
-      XUngrabKeyboard (dpy, CurrentTime);
+      read_single_key (&c, &mod, keysym_buf, keysym_bufsize);
 
       /* Destroy our number windows and free the array. */
       for (i=0; i<frames; i++)
@@ -2966,17 +2964,21 @@ cmd_resize (int interactive, struct cmdarg **args)
       unsigned int mod;
       KeySym c;
       struct list_head *bk;
+      Window focus;
+      int revert;
 
       /* If we haven't got at least 2 frames, there isn't anything to
          scale. */
       if (num_frames (s) < 2)
         return cmdret_new (RET_FAILURE, NULL);
 
-      XGrabKeyboard (dpy, s->key_window, False, GrabModeSync, GrabModeAsync, CurrentTime);
-
       /* Save the frameset in case the user aborts. */
       bk = screen_copy_frameset (s);
 
+      /* Get ready to read keys. */
+      XGetInputFocus (dpy, &focus, &revert);
+      set_window_focus (s->key_window);
+
       while (1)
         {
           struct resize_binding *binding;
@@ -3025,7 +3027,7 @@ cmd_resize (int interactive, struct cmdarg **args)
       free (bk);
 
       hide_frame_indicator ();
-      XUngrabKeyboard (dpy, CurrentTime);
+      set_window_focus (focus);
     }
   else
     {
@@ -3144,7 +3146,6 @@ cmdret *
 cmd_license (int interactive, struct cmdarg **args)
 {
   rp_screen *s = current_screen();
-  XEvent ev;
   int x = 10;
   int y = 10;
   int i;
@@ -3181,7 +3182,6 @@ cmd_license (int interactive, struct cmdarg **args)
   XInstallColormap (dpy, s->def_cmap);
 
   XMapRaised (dpy, s->help_window);
-  XGrabKeyboard (dpy, s->help_window, False, GrabModeSync, GrabModeAsync, CurrentTime);
 
   /* Find the longest line. */
   for(i=0; license_text[i]; i++)
@@ -3210,10 +3210,7 @@ cmd_license (int interactive, struct cmdarg **args)
   }
 
   /* Wait for a key press. */
-  XMaskEvent (dpy, KeyPressMask, &ev);
-
-  /* Revert focus. */
-  XUngrabKeyboard (dpy, CurrentTime);
+  read_any_key ();
   XUnmapWindow (dpy, s->help_window);
 
   /* Possibly restore colormap. */
@@ -3243,7 +3240,6 @@ cmd_help (int interactive, struct cmdarg **args)
   if (interactive)
     {
       rp_screen *s = current_screen();
-      XEvent ev;
       int i, old_i;
       int x = 10;
       int y = 0;
@@ -3257,7 +3253,6 @@ cmd_help (int interactive, struct cmdarg **args)
       XInstallColormap (dpy, s->def_cmap);
 
       XMapRaised (dpy, s->help_window);
-      XGrabKeyboard (dpy, s->help_window, False, GrabModeSync, GrabModeAsync, CurrentTime);
 
       XmbDrawString (dpy, s->help_window, defaults.font, s->normal_gc,
 		     10, y + rp_font_ascent,
@@ -3342,8 +3337,7 @@ cmd_help (int interactive, struct cmdarg **args)
             }
         }
 
-      XMaskEvent (dpy, KeyPressMask, &ev);
-      XUngrabKeyboard (dpy, CurrentTime);
+      read_any_key();
       XUnmapWindow (dpy, s->help_window);
 
       /* Possibly restore colormap. */
@@ -4953,8 +4947,6 @@ cmd_readkey (int interactive, struct cmdarg **args)
 
   map = ARG(0,keymap);
 
-  XGrabKeyboard (dpy, current_screen()->key_window, False, GrabModeSync, GrabModeAsync, CurrentTime);
-
   /* Change the mouse icon to indicate to the user we are waiting for
      more keystrokes */
   if (defaults.wait_for_key_cursor)
@@ -4963,8 +4955,7 @@ cmd_readkey (int interactive, struct cmdarg **args)
       rat_grabbed = 1;
     }
 
-  read_key (&keysym, &mod, NULL, 0);
-  XUngrabKeyboard (dpy, CurrentTime);
+  read_single_key (&keysym, &mod, NULL, 0);
 
   if (rat_grabbed)
     ungrab_rat();
@@ -5506,8 +5497,6 @@ cmd_describekey (int interactive, struct cmdarg **args)
 
   map = ARG(0,keymap);
 
-  XGrabKeyboard (dpy, current_screen()->key_window, False, GrabModeSync, GrabModeAsync, CurrentTime);
-
   /* Change the mouse icon to indicate to the user we are waiting for
      more keystrokes */
   if (defaults.wait_for_key_cursor)
@@ -5516,8 +5505,7 @@ cmd_describekey (int interactive, struct cmdarg **args)
       rat_grabbed = 1;
     }
 
-  read_key (&keysym, &mod, NULL, 0);
-  XUngrabKeyboard (dpy, CurrentTime);
+  read_single_key (&keysym, &mod, NULL, 0);
 
   if (rat_grabbed)
     ungrab_rat();
diff --git a/src/events.c b/src/events.c
index bdc288f..ec26ceb 100644
--- a/src/events.c
+++ b/src/events.c
@@ -427,6 +427,8 @@ handle_key (KeySym ks, unsigned int mod, rp_screen *s)
     {
       PRINT_DEBUG(("Impossible: No matching key"));
     }
+
+  /* All keys have been read so now we let the keyboard go. */
   XAllowEvents (dpy, AsyncKeyboard, CurrentTime);
 }
 
diff --git a/src/input.c b/src/input.c
index 3350341..3297ac7 100644
--- a/src/input.c
+++ b/src/input.c
@@ -377,6 +377,30 @@ cook_keycode (XKeyEvent *ev, KeySym *keysym, unsigned int *mod, char *keysym_nam
   return nbytes;
 }
 
+/* Wait for a key and discard it. */
+void
+read_any_key ()
+{
+  char buffer[513];
+  unsigned int mod;
+  KeySym c;
+
+  read_single_key (&c, &mod, buffer, sizeof (buffer));
+}
+
+/* The same as read_key, but handle focusing the key_window and reverting focus. */
+int
+read_single_key (KeySym *keysym, unsigned int *modifiers, char *keysym_name, int len)
+{
+  Window focus;
+  int revert;
+
+  XGetInputFocus (dpy, &focus, &revert);
+  set_window_focus (current_screen()->key_window);
+  read_key (keysym, modifiers, keysym_name, len);
+  set_window_focus (focus);
+}
+
 int
 read_key (KeySym *keysym, unsigned int *modifiers, char *keysym_name, int len)
 {
@@ -386,10 +410,13 @@ read_key (KeySym *keysym, unsigned int *modifiers, char *keysym_name, int len)
   /* Read a key from the keyboard. */
   do
     {
-      XMaskEvent (dpy, KeyPressMask, &ev);
+      /* The keyboard is frozen, so unfreeze it and allow another key to come in. */
+      XAllowEvents (dpy, SyncKeyboard, CurrentTime);
+
+      XMaskEvent (dpy, KeyPressMask|KeyRelease, &ev);
       *modifiers = ev.xkey.state;
       nbytes = cook_keycode (&ev.xkey, keysym, modifiers, keysym_name, len, 0);
-    } while (IsModifierKey (*keysym));
+    } while (IsModifierKey (*keysym) || ev.xkey.type == KeyRelease);
 
   return nbytes;
 }
@@ -503,6 +530,8 @@ get_more_input (char *prompt, char *preinput,
   rp_input_line *line;
   char *final_input;
   edit_status status;
+  Window focus;
+  int revert;
 
 #ifdef HAVE_HISTORY
   history_reset();
@@ -522,12 +551,13 @@ get_more_input (char *prompt, char *preinput,
   XMapWindow (dpy, s->input_window);
   XRaiseWindow (dpy, s->input_window);
   XClearWindow (dpy, s->input_window);
+  /* Switch focus to our input window to read the next key events. */
+  XGetInputFocus (dpy, &focus, &revert);
+  set_window_focus (s->input_window);
   XSync (dpy, False);
 
   update_input_window (s, line);
 
-  XGrabKeyboard (dpy, s->input_window, False, GrabModeSync, GrabModeAsync, CurrentTime);
-
   for (;;)
     {
       nbytes = read_key (&ch, &modifier, keysym_buf, keysym_bufsize);
@@ -566,7 +596,7 @@ get_more_input (char *prompt, char *preinput,
   input_line_free (line);
 
   /* Revert focus. */
-  XUngrabKeyboard (dpy, CurrentTime);
+  set_window_focus (focus);
   XUnmapWindow (dpy, s->input_window);
 
   /* Possibly restore colormap. */
diff --git a/src/input.h b/src/input.h
index f3da6bc..676c6e7 100644
--- a/src/input.h
+++ b/src/input.h
@@ -26,6 +26,8 @@ char *keysym_to_string (KeySym keysym, unsigned int modifier);
 int cook_keycode (XKeyEvent *ev, KeySym *keysym, unsigned int *mod, char *keysym_name, int len, int ignore_bad_mods);
 char *get_input (char *prompt, completion_fn fn);
 char *get_more_input (char *prompt, char *preinput, completion_fn fn);
+void read_any_key ();
+int read_single_key (KeySym *keysym, unsigned int *modifiers, char *keysym_name, int len);
 int read_key (KeySym *keysym, unsigned int *modifiers, char *keysym_name, int len);
 unsigned int x11_mask_to_rp_mask (unsigned int mask);
 unsigned int rp_mask_to_x11_mask (unsigned int mask);