'inccommand': Detect "non-interactive", "too slow".

command_line_changed:
  - Check (current_SID == 0) instead of KeyTyped
    - We want to update during mappings (KeyTyped is false then).
  - Check vpeekc_any()
    - Avoids unnecessary work.
    - Avoids triggering live preview during macros.
    - Caveat: This makes the redraw "stutter" if user spams (holds a key)
      in the replace pattern. But that scenario is not important.
  - Update screen if the command is changed to a non-live command.
    (`s->live` goes from true => false) => clears the preview
command_line_execute:
  - Let CTRL-C cancel live preview
do_sub:
  - Enforce a time limit ('redrawtime').
  - Unset 'inccommand' if time limit is reached.

Closes #5602
Closes #5585

runtime/doc/options.txt

@@ -3418,6 +3418,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 
 	Works for |:substitute|, |:smagic|, |:snomagic|. |hl-Substitute|
 
+	If the preview is too slow (exceeds 'redrawtime') then 'inccommand' is
+	automatically disabled until |Command-line-mode| is done.
+
 						*'include'* *'inc'*
 'include' 'inc'		string	(default "^\s*#\s*include")
 			global or local to buffer |global-local|
@@ -4733,8 +4736,8 @@ A jump table for the options with a short description can be found at |Q_op|.
 			global
 			{only available when compiled with the |+reltime|
 			feature}
-	The time in milliseconds for redrawing the display.  This applies to
+	Time in milliseconds for redrawing the display.  Applies to
-	searching for patterns for 'hlsearch' and |:match| highlighting.
+	'hlsearch', 'inccommand' and |:match| highlighting.
 	When redrawing takes more than this many milliseconds no further
 	matches will be highlighted.  This is used to avoid that Vim hangs
 	when using a very complicated pattern.

src/nvim/ex_cmds.c

@@ -3100,8 +3100,6 @@ static char_u *sub_parse_flags(char_u *cmd, subflags_T *subflags,
   return cmd;
 }
 
-/// do_sub()
-///
 /// Perform a substitution from line eap->line1 to line eap->line2 using the
 /// command pointed to by eap->arg which should be of the form:
 ///
@@ -3110,7 +3108,7 @@ static char_u *sub_parse_flags(char_u *cmd, subflags_T *subflags,
 /// The usual escapes are supported as described in the regexp docs.
 ///
 /// @return buffer used for 'inccommand' preview
-buf_T *do_sub(exarg_T *eap)
+static buf_T *do_sub(exarg_T *eap)
 {
   long i = 0;
   regmmatch_T regmatch;
@@ -3139,6 +3137,7 @@ buf_T *do_sub(exarg_T *eap)
   bool endcolumn = false;   // cursor in last column when done
   MatchedLineVec matched_lines = KV_INITIAL_VALUE;
   pos_T old_cursor = curwin->w_cursor;
+  proftime_T timeout = eap->is_live ? profile_setlimit(p_rdt) : profile_zero();
   int start_nsubs;
   int save_ma = 0;
   int save_b_changed = curbuf->b_changed;
@@ -3581,7 +3580,7 @@ buf_T *do_sub(exarg_T *eap)
                 || typed == intr_char
 #endif
                 ) {
-              got_quit = TRUE;
+              got_quit = true;
               break;
             }
             if (typed == 'n')
@@ -3882,6 +3881,10 @@ skip:
     }
 
     line_breakcheck();
+
+    if (profile_passed_limit(timeout)) {
+      got_quit = true;
+    }
   }
 
   if (first_line != 0) {
@@ -3949,10 +3952,15 @@ skip:
 
   // Show 'inccommand' preview if there are matched lines.
   buf_T *preview_buf = NULL;
-  if (eap->is_live && *p_icm != NUL && matched_lines.size != 0 && pat != NULL) {
+  if (eap->is_live && !aborting()) {
+    if (got_quit) {  // Substitution is too slow, disable 'inccommand'.
+      set_string_option_direct((char_u *)"icm", -1, (char_u *)"", OPT_FREE,
+                               SID_NONE);
+    } else if (*p_icm != NUL && matched_lines.size != 0 && pat != NULL) {
       curbuf->b_changed = save_b_changed;  // preserve 'modified' during preview
       preview_buf = show_sub(eap, old_cursor, pat, sub, &matched_lines);
     }
+  }
 
   for (MatchedLine m; kv_size(matched_lines);) {
     m = kv_pop(matched_lines);
@@ -6017,7 +6025,8 @@ static buf_T *show_sub(exarg_T *eap, pos_T old_cusr, char_u *pat, char_u *sub,
   cmdmod.tab = 0;                 // disable :tab modifier
   cmdmod.noswapfile = true;       // disable swap for preview buffer
   // disable file info message
-  set_option_value((char_u *)"shm", 0L, (char_u *)"F", 0);
+  set_string_option_direct((char_u *)"shm", -1, (char_u *)"F", OPT_FREE,
+                           SID_NONE);
 
   bool outside_curline = (eap->line1 != old_cusr.lnum
                           || eap->line2 != old_cusr.lnum);
@@ -6096,7 +6105,7 @@ static buf_T *show_sub(exarg_T *eap, pos_T old_cusr, char_u *pat, char_u *sub,
   win_size_restore(&save_winsizes);
   ga_clear(&save_winsizes);
 
-  set_option_value((char_u *)"shm", 0L, save_shm_p, 0);
+  set_string_option_direct((char_u *)"shm", -1, save_shm_p, OPT_FREE, SID_NONE);
   xfree(save_shm_p);
 
   // Update screen now. Must do this _before_ close_windows().

src/nvim/ex_getln.c

@@ -103,11 +103,13 @@ typedef struct command_line_state {
   linenr_T  old_botline;
   int did_incsearch;
   int incsearch_postponed;
+  bool live;                            // performing 'inccommand' preview
   int did_wild_list;                    // did wild_list() recently
   int wim_index;                        // index in wim_flags[]
   int res;
   int       save_msg_scroll;
   int       save_State;                 // remember State when called
+  char_u   *save_p_icm;
   int some_key_typed;                   // one of the keys was typed
   // mouse drag and release events are ignored, unless they are
   // preceded with a mouse down event
@@ -159,6 +161,7 @@ static uint8_t *command_line_enter(int firstc, long count, int indent)
   s->indent = indent;
   s->save_msg_scroll = msg_scroll;
   s->save_State = State;
+  s->save_p_icm = vim_strsave(p_icm);
   s->ignore_drag_release = true;
 
   if (s->firstc == -1) {
@@ -323,9 +326,12 @@ static uint8_t *command_line_enter(int firstc, long count, int indent)
     need_wait_return = false;
   }
 
+  set_string_option_direct((char_u *)"icm", -1, s->save_p_icm, OPT_FREE,
+                           SID_NONE);
   State = s->save_State;
   setmouse();
   ui_cursor_shape();            // may show different cursor shape
+  xfree(s->save_p_icm);
 
   {
     char_u *p = ccline.cmdbuff;
@@ -394,7 +400,8 @@ static int command_line_execute(VimState *state, int key)
   if ((s->c == Ctrl_C)
       && s->firstc != '@'
       && !s->break_ctrl_c
-      && !global_busy) {
+      && !global_busy
+      && !cmd_is_live(ccline.cmdbuff)) {
     got_int = false;
   }
 
@@ -981,7 +988,6 @@ static int command_line_handle_key(CommandLineState *s)
     status_redraw_curbuf();
     return command_line_not_changed(s);
 
-  // case '@':   only in very old vi
   case Ctrl_U:
     // delete all characters left of the cursor
     s->j = ccline.cmdpos;
@@ -996,7 +1002,6 @@ static int command_line_handle_key(CommandLineState *s)
     redrawcmd();
     return command_line_changed(s);
 
-
   case ESC:           // get here if p_wc != ESC or when ESC typed twice
   case Ctrl_C:
     // In exmode it doesn't make sense to return.  Except when
@@ -1489,11 +1494,11 @@ static int command_line_handle_key(CommandLineState *s)
 
 static int command_line_not_changed(CommandLineState *s)
 {
-  // This part implements incremental searches for "/" and "?" Jump to
+  // Incremental searches for "/" and "?":
-  // cmdline_not_changed when a character has been read but the command line
+  // Enter command_line_not_changed() when a character has been read but the
-  // did not change. Then we only search and redraw if something changed in
+  // command line did not change. Then we only search and redraw if something
-  // the past.  Jump to cmdline_changed when the command line did change.
+  // changed in the past.
-  // (Sorry for the goto's, I know it is ugly).
+  // Enter command_line_changed() when the command line did change.
   if (!s->incsearch_postponed) {
     return 1;
   }
@@ -1592,11 +1597,13 @@ static int command_line_changed(CommandLineState *s)
     redrawcmdline();
     s->did_incsearch = true;
   } else if (s->firstc == ':'
-             && KeyTyped            // only if interactive
+             && current_SID == 0    // only if interactive
              && *p_icm != NUL       // 'inccommand' is set
              && curbuf->b_p_ma      // buffer is modifiable
              && cmdline_star == 0   // not typing a password
-             && cmd_is_live(ccline.cmdbuff)) {
+             && cmd_is_live(ccline.cmdbuff)
+             && !vpeekc_any()) {
+    s->live = true;
     // process a "live" command ('inccommand')
     do_cmdline(ccline.cmdbuff, NULL, NULL, DOCMD_KEEPLINE|DOCMD_LIVE);
 
@@ -1610,6 +1617,9 @@ static int command_line_changed(CommandLineState *s)
     update_topline();
 
     redrawcmdline();
+  } else if (s->live) {
+    s->live = false;
+    update_screen(SOME_VALID);  // Clear 'inccommand' preview.
   }
 
   if (cmdmsg_rl || (p_arshape && !p_tbidi && enc_utf8)) {

src/nvim/getchar.c

@@ -1583,29 +1583,27 @@ vungetc ( /* unget one character (can only be done once!) */
   old_mouse_col = mouse_col;
 }
 
-/*
+/// get a character:
- * get a character:
+/// 1. from the stuffbuffer
- * 1. from the stuffbuffer
+///    This is used for abbreviated commands like "D" -> "d$".
- *	This is used for abbreviated commands like "D" -> "d$".
+///    Also used to redo a command for ".".
- *	Also used to redo a command for ".".
+/// 2. from the typeahead buffer
- * 2. from the typeahead buffer
+///    Stores text obtained previously but not used yet.
- *	Stores text obtained previously but not used yet.
+///    Also stores the result of mappings.
- *	Also stores the result of mappings.
+///    Also used for the ":normal" command.
- *	Also used for the ":normal" command.
+/// 3. from the user
- * 3. from the user
+///    This may do a blocking wait if "advance" is TRUE.
- *	This may do a blocking wait if "advance" is TRUE.
+///
- *
+/// if "advance" is TRUE (vgetc()):
- * if "advance" is TRUE (vgetc()):
+///    really get the character.
- *	really get the character.
+///    KeyTyped is set to TRUE in the case the user typed the key.
- *	KeyTyped is set to TRUE in the case the user typed the key.
+///    KeyStuffed is TRUE if the character comes from the stuff buffer.
- *	KeyStuffed is TRUE if the character comes from the stuff buffer.
+/// if "advance" is FALSE (vpeekc()):
- * if "advance" is FALSE (vpeekc()):
+///    just look whether there is a character available.
- *	just look whether there is a character available.
+///
- *
+/// When "no_mapping" is zero, checks for mappings in the current mode.
- * When "no_mapping" is zero, checks for mappings in the current mode.
+/// Only returns one byte (of a multi-byte character).
- * Only returns one byte (of a multi-byte character).
+/// K_SPECIAL and CSI may be escaped, need to get two more bytes then.
- * K_SPECIAL and CSI may be escaped, need to get two more bytes then.
- */
 static int vgetorpeek(int advance)
 {
   int c, c1;