vis: make core code more robust

The core vis code was originally written under the assumption that there
always exists at least one window. However, when being called from the
Lua configuration file during start up this is not yet the case.

In general, Lua code should always be placed within appropriate event
handlers e.g. vis.events.INIT for global configuration. Invoking API
functions depending on an active window from top level statements is
not supported. Where before the editor simply crashed, these changes
turn such code sections into NOPs.

Fix #561

1 files changed, 27 insertions, 16 deletions

diff --git a/vis-modes.c b/vis-modes.c
index 875d674..2e120aa 100644
--- a/vis-modes.c
+++ b/vis-modes.c
@@ -141,11 +141,14 @@ bool vis_window_mode_map(Win *win, enum VisMode id, bool force, const char *key,
 /** mode switching event handlers */
 
 static void vis_mode_normal_enter(Vis *vis, Mode *old) {
+	Win *win = vis->win;
+	if (!win)
+		return;
 	if (old != mode_get(vis, VIS_MODE_INSERT) && old != mode_get(vis, VIS_MODE_REPLACE))
 		return;
 	if (vis->autoindent && strcmp(vis->key_prev, "<Enter>") == 0) {
-		Text *txt = vis->win->file->text;
-		for (Selection *s = view_selections(vis->win->view); s; s = view_selections_next(s)) {
+		Text *txt = win->file->text;
+		for (Selection *s = view_selections(win->view); s; s = view_selections_next(s)) {
 			size_t pos = view_cursors_pos(s);
 			size_t start = text_line_start(txt, pos);
 			size_t end = text_line_end(txt, pos);
@@ -160,7 +163,7 @@ static void vis_mode_normal_enter(Vis *vis, Mode *old) {
 		}
 	}
 	macro_operator_stop(vis);
-	if (!vis->win->parent && vis->action_prev.op == &vis_operators[VIS_OP_MODESWITCH] &&
+	if (!win->parent && vis->action_prev.op == &vis_operators[VIS_OP_MODESWITCH] &&
 	    vis->action_prev.count > 1) {
 		/* temporarily disable motion, in something like `5atext`
 		 * we should only move the cursor once then insert the text */
@@ -174,7 +177,7 @@ static void vis_mode_normal_enter(Vis *vis, Mode *old) {
 		vis->action_prev.movement = motion;
 	}
 	/* make sure we can recover the current state after an editing operation */
-	vis_file_snapshot(vis, vis->win->file);
+	vis_file_snapshot(vis, win->file);
 }
 
 static void vis_mode_operator_input(Vis *vis, const char *str, size_t len) {
@@ -184,15 +187,17 @@ static void vis_mode_operator_input(Vis *vis, const char *str, size_t len) {
 }
 
 static void vis_mode_visual_enter(Vis *vis, Mode *old) {
-	if (!old->visual) {
-		for (Selection *s = view_selections(vis->win->view); s; s = view_selections_next(s))
+	Win *win = vis->win;
+	if (!old->visual && win) {
+		for (Selection *s = view_selections(win->view); s; s = view_selections_next(s))
 			view_selections_anchor(s, true);
 	}
 }
 
 static void vis_mode_visual_line_enter(Vis *vis, Mode *old) {
-	if (!old->visual) {
-		for (Selection *s = view_selections(vis->win->view); s; s = view_selections_next(s))
+	Win *win = vis->win;
+	if (!old->visual && win) {
+		for (Selection *s = view_selections(win->view); s; s = view_selections_next(s))
 			view_selections_anchor(s, true);
 	}
 	if (!vis->action.op)
@@ -200,25 +205,29 @@ static void vis_mode_visual_line_enter(Vis *vis, Mode *old) {
 }
 
 static void vis_mode_visual_line_leave(Vis *vis, Mode *new) {
+	Win *win = vis->win;
+	if (!win)
+		return;
 	if (!new->visual) {
 		if (!vis->action.op)
-			window_selection_save(vis->win);
-		view_selections_clear_all(vis->win->view);
+			window_selection_save(win);
+		view_selections_clear_all(win->view);
 	} else {
-		view_cursor_to(vis->win->view, view_cursor_get(vis->win->view));
+		view_cursor_to(win->view, view_cursor_get(win->view));
 	}
 }
 
 static void vis_mode_visual_leave(Vis *vis, Mode *new) {
-	if (!new->visual) {
+	Win *win = vis->win;
+	if (!new->visual && win) {
 		if (!vis->action.op)
-			window_selection_save(vis->win);
-		view_selections_clear_all(vis->win->view);
+			window_selection_save(win);
+		view_selections_clear_all(win->view);
 	}
 }
 
 static void vis_mode_insert_replace_enter(Vis *vis, Mode *old) {
-	if (vis->win->parent)
+	if (!vis->win || vis->win->parent)
 		return;
 	if (!vis->action.op) {
 		action_reset(&vis->action_prev);
@@ -229,7 +238,9 @@ static void vis_mode_insert_replace_enter(Vis *vis, Mode *old) {
 }
 
 static void vis_mode_insert_idle(Vis *vis) {
-	vis_file_snapshot(vis, vis->win->file);
+	Win *win = vis->win;
+	if (win)
+		vis_file_snapshot(vis, win->file);
 }
 
 static void vis_mode_insert_input(Vis *vis, const char *str, size_t len) {