main: Extract normal_check from main_loop

The new function contains logic that must be executed after handling input in
normal mode and also before the first main loop iteration. Also rename
`main_loop` to `normal_enter` and move it to normal.c

src/nvim/ex_docmd.c

@@ -6544,7 +6544,7 @@ do_exedit (
         msg_scroll = 0;
         must_redraw = CLEAR;
 
-        main_loop(FALSE, TRUE);
+        normal_enter(false, true);
 
         RedrawingDisabled = rd;
         no_wait_return = nwr;

src/nvim/ex_getln.c

@@ -4943,7 +4943,7 @@ static int ex_window(void)
    * Call the main loop until <CR> or CTRL-C is typed.
    */
   cmdwin_result = 0;
-  main_loop(TRUE, FALSE);
+  normal_enter(true, false);
 
   RedrawingDisabled = i;
 

src/nvim/main.c

@@ -528,228 +528,16 @@ int main(int argc, char **argv)
   }
 
   TIME_MSG("before starting main loop");
+  ILOG("Starting Neovim main loop.");
 
   /*
    * Call the main command loop.  This never returns.
    */
-  main_loop(FALSE, FALSE);
+  normal_enter(false, false);
 
   return 0;
 }
 
-/*
- * Main loop: Execute Normal mode commands until exiting Vim.
- * Also used to handle commands in the command-line window, until the window
- * is closed.
- * Also used to handle ":visual" command after ":global": execute Normal mode
- * commands, return when entering Ex mode.  "noexmode" is TRUE then.
- */
-void
-main_loop (
-    int cmdwin,                 /* TRUE when working in the command-line window */
-    int noexmode               /* TRUE when return on entering Ex mode */
-)
-{
-  oparg_T oa;                                   /* operator arguments */
-  int previous_got_int = FALSE;                 /* "got_int" was TRUE */
-  linenr_T conceal_old_cursor_line = 0;
-  linenr_T conceal_new_cursor_line = 0;
-  int conceal_update_lines = FALSE;
-
-  ILOG("Starting Neovim main loop.");
-
-  clear_oparg(&oa);
-  while (!cmdwin
-      || cmdwin_result == 0
-      ) {
-    if (stuff_empty()) {
-      did_check_timestamps = FALSE;
-      if (need_check_timestamps)
-        check_timestamps(FALSE);
-      if (need_wait_return)             /* if wait_return still needed ... */
-        wait_return(FALSE);             /* ... call it now */
-      if (need_start_insertmode && goto_im()
-          && !VIsual_active
-         ) {
-        need_start_insertmode = FALSE;
-        stuffReadbuff((char_u *)"i");           /* start insert mode next */
-        /* skip the fileinfo message now, because it would be shown
-         * after insert mode finishes! */
-        need_fileinfo = FALSE;
-      }
-    }
-
-    /* Reset "got_int" now that we got back to the main loop.  Except when
-     * inside a ":g/pat/cmd" command, then the "got_int" needs to abort
-     * the ":g" command.
-     * For ":g/pat/vi" we reset "got_int" when used once.  When used
-     * a second time we go back to Ex mode and abort the ":g" command. */
-    if (got_int) {
-      if (noexmode && global_busy && !exmode_active && previous_got_int) {
-        /* Typed two CTRL-C in a row: go back to ex mode as if "Q" was
-         * used and keep "got_int" set, so that it aborts ":g". */
-        exmode_active = EXMODE_NORMAL;
-        State = NORMAL;
-      } else if (!global_busy || !exmode_active) {
-        if (!quit_more)
-          (void)vgetc();                        /* flush all buffers */
-        got_int = FALSE;
-      }
-      previous_got_int = TRUE;
-    } else
-      previous_got_int = FALSE;
-
-    if (!exmode_active)
-      msg_scroll = FALSE;
-    quit_more = FALSE;
-
-    /*
-     * If skip redraw is set (for ":" in wait_return()), don't redraw now.
-     * If there is nothing in the stuff_buffer or do_redraw is TRUE,
-     * update cursor and redraw.
-     */
-    if (skip_redraw || exmode_active)
-      skip_redraw = FALSE;
-    else if (do_redraw || stuff_empty()) {
-      /* Trigger CursorMoved if the cursor moved. */
-      if (!finish_op && (
-            has_cursormoved()
-            ||
-            curwin->w_p_cole > 0
-            )
-          && !equalpos(last_cursormoved, curwin->w_cursor)) {
-        if (has_cursormoved())
-          apply_autocmds(EVENT_CURSORMOVED, NULL, NULL,
-              FALSE, curbuf);
-        if (curwin->w_p_cole > 0) {
-          conceal_old_cursor_line = last_cursormoved.lnum;
-          conceal_new_cursor_line = curwin->w_cursor.lnum;
-          conceal_update_lines = TRUE;
-        }
-        last_cursormoved = curwin->w_cursor;
-      }
-
-      /* Trigger TextChanged if b_changedtick differs. */
-      if (!finish_op && has_textchanged()
-          && last_changedtick != curbuf->b_changedtick) {
-        if (last_changedtick_buf == curbuf)
-          apply_autocmds(EVENT_TEXTCHANGED, NULL, NULL,
-              FALSE, curbuf);
-        last_changedtick_buf = curbuf;
-        last_changedtick = curbuf->b_changedtick;
-      }
-
-      /* Scroll-binding for diff mode may have been postponed until
-       * here.  Avoids doing it for every change. */
-      if (diff_need_scrollbind) {
-        check_scrollbind((linenr_T)0, 0L);
-        diff_need_scrollbind = FALSE;
-      }
-      /* Include a closed fold completely in the Visual area. */
-      foldAdjustVisual();
-      /*
-       * When 'foldclose' is set, apply 'foldlevel' to folds that don't
-       * contain the cursor.
-       * When 'foldopen' is "all", open the fold(s) under the cursor.
-       * This may mark the window for redrawing.
-       */
-      if (hasAnyFolding(curwin) && !char_avail()) {
-        foldCheckClose();
-        if (fdo_flags & FDO_ALL)
-          foldOpenCursor();
-      }
-
-      /*
-       * Before redrawing, make sure w_topline is correct, and w_leftcol
-       * if lines don't wrap, and w_skipcol if lines wrap.
-       */
-      update_topline();
-      validate_cursor();
-
-      if (VIsual_active)
-        update_curbuf(INVERTED);        /* update inverted part */
-      else if (must_redraw)
-        update_screen(0);
-      else if (redraw_cmdline || clear_cmdline)
-        showmode();
-      redraw_statuslines();
-      if (need_maketitle)
-        maketitle();
-      /* display message after redraw */
-      if (keep_msg != NULL) {
-        char_u *p;
-
-        // msg_attr_keep() will set keep_msg to NULL, must free the string
-        // here. Don't reset keep_msg, msg_attr_keep() uses it to check for
-        // duplicates.
-        p = keep_msg;
-        msg_attr(p, keep_msg_attr);
-        xfree(p);
-      }
-      if (need_fileinfo) {              /* show file info after redraw */
-        fileinfo(FALSE, TRUE, FALSE);
-        need_fileinfo = FALSE;
-      }
-
-      emsg_on_display = FALSE;          /* can delete error message now */
-      did_emsg = FALSE;
-      msg_didany = FALSE;               /* reset lines_left in msg_start() */
-      may_clear_sb_text();              /* clear scroll-back text on next msg */
-      showruler(FALSE);
-
-      if (conceal_update_lines
-          && (conceal_old_cursor_line != conceal_new_cursor_line
-            || conceal_cursor_line(curwin)
-            || need_cursor_line_redraw)) {
-        if (conceal_old_cursor_line != conceal_new_cursor_line
-            && conceal_old_cursor_line
-            <= curbuf->b_ml.ml_line_count)
-          update_single_line(curwin, conceal_old_cursor_line);
-        update_single_line(curwin, conceal_new_cursor_line);
-        curwin->w_valid &= ~VALID_CROW;
-      }
-      setcursor();
-
-      do_redraw = FALSE;
-
-      /* Now that we have drawn the first screen all the startup stuff
-       * has been done, close any file for startup messages. */
-      if (time_fd != NULL) {
-        TIME_MSG("first screen update");
-        TIME_MSG("--- NVIM STARTED ---");
-        fclose(time_fd);
-        time_fd = NULL;
-      }
-    }
-
-    /*
-     * Update w_curswant if w_set_curswant has been set.
-     * Postponed until here to avoid computing w_virtcol too often.
-     */
-    update_curswant();
-
-    /*
-     * May perform garbage collection when waiting for a character, but
-     * only at the very toplevel.  Otherwise we may be using a List or
-     * Dict internally somewhere.
-     * "may_garbage_collect" is reset in vgetc() which is invoked through
-     * do_exmode() and normal_cmd().
-     */
-    may_garbage_collect = (!cmdwin && !noexmode);
-    /*
-     * If we're invoked as ex, do a round of ex commands.
-     * Otherwise, get and execute a normal mode command.
-     */
-    if (exmode_active) {
-      if (noexmode)         /* End of ":global/path/visual" commands */
-        return;
-      do_exmode(exmode_active == EXMODE_VIM);
-    } else
-      normal_cmd(&oa, TRUE);
-  }
-}
-
-
 /* Exit properly */
 void getout(int exitval)
 {
@@ -2075,3 +1863,5 @@ static void check_swap_exists_action(void)
     getout(1);
   handle_swap_exists(NULL);
 }
+
+

src/nvim/normal.c

@@ -65,6 +65,19 @@
 #include "nvim/os/time.h"
 #include "nvim/os/input.h"
 
+typedef struct normal_state {
+  linenr_T conceal_old_cursor_line;
+  linenr_T conceal_new_cursor_line;
+  bool conceal_update_lines;
+  bool previous_got_int;             // `got_int` was true
+  bool cmdwin;                       // command-line window normal mode
+  bool noexmode;                     // true if the normal mode was pushed from
+                                     // ex mode(:global or :visual for example)
+  bool toplevel;                     // top-level normal mode
+  oparg_T oa;                        // operator arguments
+  cmdarg_T ca;                       // command arguments
+} NormalState;
+
 /*
  * The Visual area is remembered for reselection.
  */
@@ -79,6 +92,12 @@ static int restart_VIsual_select = 0;
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "normal.c.generated.h"
 #endif
+
+static inline void normal_state_init(NormalState *s)
+{
+  memset(s, 0, sizeof(NormalState));
+}
+
 /*
  * nv_*(): functions called to handle Normal and Visual mode commands.
  * n_*(): functions called to handle Normal mode commands.
@@ -418,6 +437,34 @@ static int find_command(int cmdchar)
   return idx;
 }
 
+// Normal state entry point. This is called on:
+//
+// - Startup, In this case the function never returns.
+// - The command-line window is opened(`q:`). Returns when `cmdwin_result` != 0.
+// - The :visual command is called from :global in ex mode, `:global/PAT/visual`
+//   for example. Returns when re-entering ex mode(because ex mode recursion is
+//   not allowed)
+//
+// This used to be called main_loop on main.c
+void normal_enter(bool cmdwin, bool noexmode)
+{
+  NormalState state;
+  normal_state_init(&state);
+  state.cmdwin = cmdwin;
+  state.noexmode = noexmode;
+  state.toplevel = !cmdwin && !noexmode;
+
+  for (;;) {
+    int check_result = normal_check(&state);
+    if (!check_result) {
+      break;
+    } else if (check_result == -1) {
+      continue;
+    }
+    normal_cmd(&state.oa, true);
+  }
+}
+
 /*
  * Execute a command in Normal mode.
  */
@@ -1064,6 +1111,209 @@ normal_end:
   opcount = ca.opcount;
 }
 
+// Function executed before each iteration of normal mode.
+// Return:
+//   1 if the iteration should continue normally
+//   -1 if the iteration should be skipped
+//   0 if the main loop must exit
+static int normal_check(NormalState *s)
+{
+  if (stuff_empty()) {
+    did_check_timestamps = false;
+
+    if (need_check_timestamps) {
+      check_timestamps(false);
+    }
+
+    if (need_wait_return) {
+      // if wait_return still needed call it now
+      wait_return(false);
+    }
+
+    if (need_start_insertmode && goto_im() && !VIsual_active) {
+      need_start_insertmode = false;
+      stuffReadbuff((uint8_t *)"i");  // start insert mode next
+      // skip the fileinfo message now, because it would be shown
+      // after insert mode finishes!
+      need_fileinfo = false;
+    }
+  }
+
+  // Reset "got_int" now that we got back to the main loop.  Except when
+  // inside a ":g/pat/cmd" command, then the "got_int" needs to abort
+  // the ":g" command.
+  // For ":g/pat/vi" we reset "got_int" when used once.  When used
+  // a second time we go back to Ex mode and abort the ":g" command.
+  if (got_int) {
+    if (s->noexmode && global_busy && !exmode_active
+        && s->previous_got_int) {
+      // Typed two CTRL-C in a row: go back to ex mode as if "Q" was
+      // used and keep "got_int" set, so that it aborts ":g".
+      exmode_active = EXMODE_NORMAL;
+      State = NORMAL;
+    } else if (!global_busy || !exmode_active) {
+      if (!quit_more) {
+        // flush all buffers
+        (void)vgetc();
+      }
+      got_int = false;
+    }
+    s->previous_got_int = true;
+  } else {
+    s->previous_got_int = false;
+  }
+
+  if (!exmode_active) {
+    msg_scroll = false;
+  }
+  quit_more = false;
+
+  // If skip redraw is set (for ":" in wait_return()), don't redraw now.
+  // If there is nothing in the stuff_buffer or do_redraw is TRUE,
+  // update cursor and redraw.
+  if (skip_redraw || exmode_active) {
+    skip_redraw = false;
+  } else if (do_redraw || stuff_empty()) {
+    // Trigger CursorMoved if the cursor moved.
+    if (!finish_op && (has_cursormoved() || curwin->w_p_cole > 0)
+        && !equalpos(last_cursormoved, curwin->w_cursor)) {
+      if (has_cursormoved()) {
+        apply_autocmds(EVENT_CURSORMOVED, NULL, NULL, false, curbuf);
+      }
+
+      if (curwin->w_p_cole > 0) {
+        s->conceal_old_cursor_line = last_cursormoved.lnum;
+        s->conceal_new_cursor_line = curwin->w_cursor.lnum;
+        s->conceal_update_lines = true;
+      }
+
+      last_cursormoved = curwin->w_cursor;
+    }
+
+    // Trigger TextChanged if b_changedtick differs.
+    if (!finish_op && has_textchanged()
+        && last_changedtick != curbuf->b_changedtick) {
+      if (last_changedtick_buf == curbuf) {
+        apply_autocmds(EVENT_TEXTCHANGED, NULL, NULL, false, curbuf);
+      }
+
+      last_changedtick_buf = curbuf;
+      last_changedtick = curbuf->b_changedtick;
+    }
+
+    // Scroll-binding for diff mode may have been postponed until
+    // here.  Avoids doing it for every change.
+    if (diff_need_scrollbind) {
+      check_scrollbind((linenr_T)0, 0L);
+      diff_need_scrollbind = false;
+    }
+
+    // Include a closed fold completely in the Visual area.
+    foldAdjustVisual();
+
+    // When 'foldclose' is set, apply 'foldlevel' to folds that don't
+    // contain the cursor.
+    // When 'foldopen' is "all", open the fold(s) under the cursor.
+    // This may mark the window for redrawing.
+    if (hasAnyFolding(curwin) && !char_avail()) {
+      foldCheckClose();
+
+      if (fdo_flags & FDO_ALL) {
+        foldOpenCursor();
+      }
+    }
+
+    // Before redrawing, make sure w_topline is correct, and w_leftcol
+    // if lines don't wrap, and w_skipcol if lines wrap.
+    update_topline();
+    validate_cursor();
+
+    if (VIsual_active) {
+      update_curbuf(INVERTED);  // update inverted part
+    } else if (must_redraw) {
+      update_screen(0);
+    } else if (redraw_cmdline || clear_cmdline) {
+      showmode();
+    }
+
+    redraw_statuslines();
+
+    if (need_maketitle) {
+      maketitle();
+    }
+
+    // display message after redraw
+    if (keep_msg != NULL) {
+      // msg_attr_keep() will set keep_msg to NULL, must free the string here.
+      // Don't reset keep_msg, msg_attr_keep() uses it to check for duplicates.
+      char *p = (char *)keep_msg;
+      msg_attr((uint8_t *)p, keep_msg_attr);
+      xfree(p);
+    }
+
+    if (need_fileinfo) {  // show file info after redraw
+      fileinfo(false, true, false);
+      need_fileinfo = false;
+    }
+
+    emsg_on_display = false;  // can delete error message now
+    did_emsg = false;
+    msg_didany = false;  // reset lines_left in msg_start()
+    may_clear_sb_text();  // clear scroll-back text on next msg
+    showruler(false);
+
+    if (s->conceal_update_lines
+        && (s->conceal_old_cursor_line !=
+          s->conceal_new_cursor_line
+          || conceal_cursor_line(curwin)
+          || need_cursor_line_redraw)) {
+      if (s->conceal_old_cursor_line !=
+          s->conceal_new_cursor_line
+          && s->conceal_old_cursor_line <=
+          curbuf->b_ml.ml_line_count) {
+        update_single_line(curwin, s->conceal_old_cursor_line);
+      }
+
+      update_single_line(curwin, s->conceal_new_cursor_line);
+      curwin->w_valid &= ~VALID_CROW;
+    }
+
+    setcursor();
+
+    do_redraw = false;
+
+    // Now that we have drawn the first screen all the startup stuff
+    // has been done, close any file for startup messages.
+    if (time_fd != NULL) {
+      TIME_MSG("first screen update");
+      TIME_MSG("--- NVIM STARTED ---");
+      fclose(time_fd);
+      time_fd = NULL;
+    }
+  }
+
+  // May perform garbage collection when waiting for a character, but
+  // only at the very toplevel.  Otherwise we may be using a List or
+  // Dict internally somewhere.
+  // "may_garbage_collect" is reset in vgetc() which is invoked through
+  // do_exmode() and normal_cmd().
+  may_garbage_collect = s->toplevel;
+
+  // Update w_curswant if w_set_curswant has been set.
+  // Postponed until here to avoid computing w_virtcol too often.
+  update_curswant();
+
+  if (exmode_active) {
+    if (s->noexmode) {
+      return 0;
+    }
+    do_exmode(exmode_active == EXMODE_VIM);
+    return -1;
+  }
+
+  return !s->cmdwin || cmdwin_result == 0;
+}
+
 /*
  * Set v:count and v:count1 according to "cap".
  * Set v:prevcount only when "set_prevcount" is true.
@@ -7376,3 +7626,4 @@ static int mouse_model_popup(void)
 {
   return p_mousem[0] == 'p';
 }
+