[Emacs-diffs] master efa750e: Simplify read_key_sequence

[Paul Eggert]

branch: master
commit efa750e68466fb1bab03028701350a745e0504b6
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>

    Simplify read_key_sequence
    
    * src/keyboard.c (READ_KEY_ELTS): New constant.
    (keyremap_step, read_key_sequence): Omit BUFSIZE arg, since it's
    always READ_KEY_ELTS.  All callers changed.
    (grow_bool_vector): Remove; no longer needed.
    (read_key_sequence): Use a bool array instead of a Lisp bool
    vector, since it's small and this puts less pressure on the GC.
---
 src/keyboard.c | 98 ++++++++++++++++++----------------------------------------
 1 file changed, 30 insertions(+), 68 deletions(-)

diff --git a/src/keyboard.c b/src/keyboard.c
index c92684d..e6b5cf7 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -1251,7 +1251,8 @@ some_mouse_moved (void)
 /* This is the actual command reading loop,
    sans error-handling encapsulation.  */
 
-static int read_key_sequence (Lisp_Object *, int, Lisp_Object,
+enum { READ_KEY_ELTS = 30 };
+static int read_key_sequence (Lisp_Object *, Lisp_Object,
                               bool, bool, bool, bool);
 static void adjust_point_for_property (ptrdiff_t, bool);
 
@@ -1299,11 +1300,9 @@ command_loop_1 (void)
   if (!CONSP (last_command_event))
     kset_last_repeatable_command (current_kboard, Vreal_this_command);
 
-  while (1)
+  while (true)
     {
       Lisp_Object cmd;
-      Lisp_Object keybuf[30];
-      int i;
 
       if (! FRAME_LIVE_P (XFRAME (selected_frame)))
        Fkill_emacs (Qnil);
@@ -1367,8 +1366,8 @@ command_loop_1 (void)
 
       /* Read next key sequence; i gets its length.  */
       raw_keybuf_count = 0;
-      i = read_key_sequence (keybuf, ARRAYELTS (keybuf),
-                            Qnil, 0, 1, 1, 0);
+      Lisp_Object keybuf[READ_KEY_ELTS];
+      int i = read_key_sequence (keybuf, Qnil, false, true, true, false);
 
       /* A filter may have run while we were reading the input.  */
       if (! FRAME_LIVE_P (XFRAME (selected_frame)))
@@ -1604,16 +1603,14 @@ command_loop_1 (void)
 Lisp_Object
 read_menu_command (void)
 {
-  Lisp_Object keybuf[30];
   ptrdiff_t count = SPECPDL_INDEX ();
-  int i;
 
   /* We don't want to echo the keystrokes while navigating the
      menus.  */
   specbind (Qecho_keystrokes, make_number (0));
 
-  i = read_key_sequence (keybuf, ARRAYELTS (keybuf),
-                        Qnil, 0, 1, 1, 1);
+  Lisp_Object keybuf[READ_KEY_ELTS];
+  int i = read_key_sequence (keybuf, Qnil, false, true, true, true);
 
   unbind_to (count, Qnil);
 
@@ -8778,8 +8775,7 @@ access_keymap_keyremap (Lisp_Object map, Lisp_Object key, 
Lisp_Object prompt,
 
 /* Do one step of the key remapping used for function-key-map and
    key-translation-map:
-   KEYBUF is the buffer holding the input events.
-   BUFSIZE is its maximum size.
+   KEYBUF is the READ_KEY_ELTS-size buffer holding the input events.
    FKEY is a pointer to the keyremap structure to use.
    INPUT is the index of the last element in KEYBUF.
    DOIT if true says that the remapping can actually take place.
@@ -8789,7 +8785,7 @@ access_keymap_keyremap (Lisp_Object map, Lisp_Object key, 
Lisp_Object prompt,
    Return true if the remapping actually took place.  */
 
 static bool
-keyremap_step (Lisp_Object *keybuf, int bufsize, volatile keyremap *fkey,
+keyremap_step (Lisp_Object *keybuf, volatile keyremap *fkey,
               int input, bool doit, int *diff, Lisp_Object prompt)
 {
   Lisp_Object next, key;
@@ -8811,7 +8807,7 @@ keyremap_step (Lisp_Object *keybuf, int bufsize, volatile 
keyremap *fkey,
 
       *diff = len - (fkey->end - fkey->start);
 
-      if (bufsize - input <= *diff)
+      if (READ_KEY_ELTS - input <= *diff)
        error ("Key sequence too long");
 
       /* Shift the keys that follow fkey->end.  */
@@ -8858,33 +8854,8 @@ void init_raw_keybuf_count (void)
   raw_keybuf_count = 0;
 }
 
-/* Grow a vector to fit.
-
-  On entry, *VECTOR is nil or a bool vector.  Upon return, *VECTOR
-  contains a bool vector of size at least NEEDED_LENGTH, with any new
-  values to false.  Return the new value of *VECTOR.  */
-static Lisp_Object
-grow_bool_vector (Lisp_Object *vector, int needed_length)
-{
-  EMACS_INT old_length = NILP (*vector) ? 0 : bool_vector_size (*vector);
-  if (NILP (*vector) || old_length < needed_length)
-    {
-      EMACS_INT new_length = old_length ? old_length : 64;
-      while (new_length < needed_length)
-        new_length *= 2;
-      Lisp_Object new_vector =
-        Fmake_bool_vector (make_number (needed_length), Qnil);
-      if (old_length)
-        memcpy (bool_vector_data (new_vector),
-                bool_vector_data (*vector),
-                bool_vector_bytes (old_length));
-      *vector = new_vector;
-    }
-  return *vector;
-}
-
 /* Read a sequence of keys that ends with a non prefix character,
-   storing it in KEYBUF, a buffer of size BUFSIZE.
+   storing it in KEYBUF, a buffer of size READ_KEY_ELTS.
    Prompt with PROMPT.
    Return the length of the key sequence stored.
    Return -1 if the user rejected a command menu.
@@ -8924,7 +8895,7 @@ grow_bool_vector (Lisp_Object *vector, int needed_length)
    from the selected window's buffer.  */
 
 static int
-read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
+read_key_sequence (Lisp_Object *keybuf, Lisp_Object prompt,
                   bool dont_downcase_last, bool can_return_switch_frame,
                   bool fix_current_buffer, bool prevent_redisplay)
 {
@@ -8959,10 +8930,8 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
      reading characters from the keyboard.  */
   int mock_input = 0;
 
-  /* This bool vector remembers whether each event in the mocked input
-     came from a mouse menu.  We ordinarily leave it nil and create it
-     the first time we remember a mouse event.  */
-  Lisp_Object used_mouse_menu_history = Qnil;
+  /* Whether each event in the mocked input came from a mouse menu.  */
+  bool used_mouse_menu_history[READ_KEY_ELTS] = {0};
 
   /* Distinguish first time through from replay with mock_input == 0.  */
   bool is_replay = false;
@@ -9057,7 +9026,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
  replay_sequence:
 
   starting_buffer = current_buffer;
-  first_unbound = bufsize + 1;
+  first_unbound = READ_KEY_ELTS + 1;
   Lisp_Object first_event = mock_input > 0 ? keybuf[0] : Qnil;
   Lisp_Object second_event = mock_input > 1 ? keybuf[1] : Qnil;
 
@@ -9139,7 +9108,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
          goto replay_sequence;
        }
 
-      if (t >= bufsize)
+      if (t >= READ_KEY_ELTS)
        error ("Key sequence too long");
 
       if (INTERACTIVE)
@@ -9170,9 +9139,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
              current_kboard->immediate_echo = false;
              echo_now ();
            }
-          used_mouse_menu = !NILP (used_mouse_menu_history) &&
-            t < bool_vector_size (used_mouse_menu_history) &&
-            bool_vector_bitref (used_mouse_menu_history, t);
+         used_mouse_menu = used_mouse_menu_history[t];
        }
 
       /* If not, we should actually read a character.  */
@@ -9186,10 +9153,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
            key = read_char (prevent_redisplay ? -2 : NILP (prompt),
                             current_binding, last_nonmenu_event,
                              &used_mouse_menu, NULL);
-            if (used_mouse_menu || !NILP (used_mouse_menu_history))
-              bool_vector_set (
-                grow_bool_vector (&used_mouse_menu_history, t + 1),
-                t, used_mouse_menu);
+           used_mouse_menu_history[t] = used_mouse_menu;
            if ((INTEGERP (key) && XINT (key) == -2) /* wrong_kboard_jmpbuf */
                /* When switching to a new tty (with a new keyboard),
                   read_char returns the new buffer, rather than -2
@@ -9417,7 +9381,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
                  && (NILP (fake_prefixed_keys)
                      || NILP (Fmemq (key, fake_prefixed_keys))))
                {
-                 if (bufsize - t <= 1)
+                 if (READ_KEY_ELTS - t <= 1)
                    error ("Key sequence too long");
 
                  keybuf[t]     = posn;
@@ -9443,7 +9407,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
                 insert the dummy prefix event `menu-bar'.  */
              if (EQ (posn, Qmenu_bar) || EQ (posn, Qtool_bar))
                {
-                 if (bufsize - t <= 1)
+                 if (READ_KEY_ELTS - t <= 1)
                    error ("Key sequence too long");
                  keybuf[t] = posn;
                  keybuf[t + 1] = key;
@@ -9646,8 +9610,8 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
          bool done;
          int diff;
 
-         done = keyremap_step (keybuf, bufsize, &indec, max (t, mock_input),
-                               1, &diff, prompt);
+         done = keyremap_step (keybuf, &indec, max (t, mock_input),
+                               true, &diff, prompt);
          if (done)
            {
              mock_input = diff + max (t, mock_input);
@@ -9677,13 +9641,13 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
            bool done;
            int diff;
 
-           done = keyremap_step (keybuf, bufsize, &fkey,
+           done = keyremap_step (keybuf, &fkey,
                                  max (t, mock_input),
                                  /* If there's a binding (i.e.
                                     first_binding >= nmaps) we don't want
                                     to apply this function-key-mapping.  */
-                                 fkey.end + 1 == t
-                                 && (test_undefined (current_binding)),
+                                 (fkey.end + 1 == t
+                                  && test_undefined (current_binding)),
                                  &diff, prompt);
            if (done)
              {
@@ -9703,8 +9667,8 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, 
Lisp_Object prompt,
          bool done;
          int diff;
 
-         done = keyremap_step (keybuf, bufsize, &keytran, max (t, mock_input),
-                               1, &diff, prompt);
+         done = keyremap_step (keybuf, &keytran, max (t, mock_input),
+                               true, &diff, prompt);
          if (done)
            {
              mock_input = diff + max (t, mock_input);
@@ -9857,8 +9821,6 @@ read_key_sequence_vs (Lisp_Object prompt, Lisp_Object 
continue_echo,
                      Lisp_Object can_return_switch_frame,
                      Lisp_Object cmd_loop, bool allow_string)
 {
-  Lisp_Object keybuf[30];
-  int i;
   ptrdiff_t count = SPECPDL_INDEX ();
 
   if (!NILP (prompt))
@@ -9882,9 +9844,9 @@ read_key_sequence_vs (Lisp_Object prompt, Lisp_Object 
continue_echo,
 #endif
 
   raw_keybuf_count = 0;
-  i = read_key_sequence (keybuf, ARRAYELTS (keybuf),
-                        prompt, ! NILP (dont_downcase_last),
-                        ! NILP (can_return_switch_frame), 0, 0);
+  Lisp_Object keybuf[READ_KEY_ELTS];
+  int i = read_key_sequence (keybuf, prompt, ! NILP (dont_downcase_last),
+                            ! NILP (can_return_switch_frame), false, false);
 
 #if 0  /* The following is fine for code reading a key sequence and
          then proceeding with a lengthy computation, but it's not good