vis: perform undo snapshotting more rarerly

Do not take snapshots after every operation in insert/replace mode.
As an example up until now we would take a snapshot after every
<Backspace>/<Delete> press, hence when undoing changes each character
would be restored individually. The same applies for <C-w> and related
actions.

From now on we only snaphost when:

 - transitioning from insert/replace mode to normal mode (but not when
   switching to operator pending mode)

 - an operation takes place from normal mode

 - an idle time expires in normal/replace mode

1 files changed, 8 insertions, 6 deletions

diff --git a/vis-modes.c b/vis-modes.c
index a10d214..7008161 100644
--- a/vis-modes.c
+++ b/vis-modes.c
@@ -132,10 +132,11 @@ static void vis_mode_insert_enter(Vis *vis, Mode *old) {
 }
 
 static void vis_mode_insert_leave(Vis *vis, Mode *new) {
-	/* make sure we can recover the current state after an editing operation */
-	text_snapshot(vis->win->file->text);
-	if (new == mode_get(vis, VIS_MODE_NORMAL))
+	if (new == mode_get(vis, VIS_MODE_NORMAL)) {
+		/* make sure we can recover the current state after an editing operation */
+		text_snapshot(vis->win->file->text);
 		macro_operator_stop(vis);
+	}
 }
 
 static void vis_mode_insert_idle(Vis *vis) {
@@ -161,10 +162,11 @@ static void vis_mode_replace_enter(Vis *vis, Mode *old) {
 }
 
 static void vis_mode_replace_leave(Vis *vis, Mode *new) {
-	/* make sure we can recover the current state after an editing operation */
-	text_snapshot(vis->win->file->text);
-	if (new == mode_get(vis, VIS_MODE_NORMAL))
+	if (new == mode_get(vis, VIS_MODE_NORMAL)) {
+		/* make sure we can recover the current state after an editing operation */
+		text_snapshot(vis->win->file->text);
 		macro_operator_stop(vis);
+	}
 }
 
 static void vis_mode_replace_input(Vis *vis, const char *str, size_t len) {