Fix issues in the command prompt: set PROMPT_QUOTENEXT after quoting

than before, meaning that accidentally scrolling the mouse wheel doesn't
break quoting; and move the cursor correctly over wide characters. From
Alexander Arch in GitHub issue 4212.

status.c

@@ -728,6 +728,55 @@ status_prompt_update(struct client *c, const char *msg, const char *input)
 	format_free(ft);
 }
 
+/* Redraw character. Return 1 if can continue redrawing, 0 otherwise. */
+static int
+status_prompt_redraw_character(struct screen_write_ctx *ctx, u_int offset,
+    u_int pwidth, u_int *width, struct grid_cell *gc,
+    const struct utf8_data *ud)
+{
+	u_char	ch;
+
+	if (*width < offset) {
+		*width += ud->width;
+		return (1);
+	}
+	if (*width >= offset + pwidth)
+		return (0);
+	*width += ud->width;
+	if (*width > offset + pwidth)
+		return (0);
+
+	ch = *ud->data;
+	if (ud->size == 1 && (ch <= 0x1f || ch == 0x7f)) {
+		gc->data.data[0] = '^';
+		gc->data.data[1] = (ch == 0x7f) ? '?' : ch|0x40;
+		gc->data.size = gc->data.have = 2;
+		gc->data.width = 2;
+	} else
+		utf8_copy(&gc->data, ud);
+	screen_write_cell(ctx, gc);
+	return (1);
+}
+
+/*
+ * Redraw quote indicator '^' if necessary. Return 1 if can continue redrawing,
+ * 0 otherwise.
+ */
+static int
+status_prompt_redraw_quote(const struct client *c, u_int pcursor,
+    struct screen_write_ctx *ctx, u_int offset, u_int pwidth, u_int *width,
+    struct grid_cell *gc)
+{
+	struct utf8_data	ud;
+
+	if (c->prompt_flags & PROMPT_QUOTENEXT && ctx->s->cx == pcursor + 1) {
+		utf8_set(&ud, '^');
+		return (status_prompt_redraw_character(ctx, offset, pwidth,
+		    width, gc, &ud));
+	}
+	return (1);
+}
+
 /* Draw client prompt on status line of present else on last line. */
 int
 status_prompt_redraw(struct client *c)
@@ -740,8 +789,6 @@ status_prompt_redraw(struct client *c)
 	u_int			 pcursor, pwidth, promptline;
 	struct grid_cell	 gc;
 	struct format_tree	*ft;
-	u_char			 ch;
-	struct utf8_data	*ud;
 
 	if (c->tty.sx == 0 || c->tty.sy == 0)
 		return (0);
@@ -788,6 +835,8 @@ status_prompt_redraw(struct client *c)
 
 	pcursor = utf8_strwidth(c->prompt_buffer, c->prompt_index);
 	pwidth = utf8_strwidth(c->prompt_buffer, -1);
+	if (c->prompt_flags & PROMPT_QUOTENEXT)
+		pwidth++;
 	if (pcursor >= left) {
 		/*
 		 * The cursor would be outside the screen so start drawing
@@ -799,31 +848,19 @@ status_prompt_redraw(struct client *c)
 		offset = 0;
 	if (pwidth > left)
 		pwidth = left;
-	c->prompt_cursor = start + c->prompt_index - offset;
+	c->prompt_cursor = start + pcursor - offset;
 
 	width = 0;
 	for (i = 0; c->prompt_buffer[i].size != 0; i++) {
-		ud = &c->prompt_buffer[i];
+		if (!status_prompt_redraw_quote(c, pcursor, &ctx, offset,
-		if (width < offset) {
+		    pwidth, &width, &gc))
-			width += ud->width;
-			continue;
-		}
-		if (width >= offset + pwidth)
 			break;
-		width += ud->width;
+		if (!status_prompt_redraw_character(&ctx, offset, pwidth,
-		if (width > offset + pwidth)
+		    &width, &gc, &c->prompt_buffer[i]))
 			break;
-
-		ch = *ud->data;
-		if (ud->size == 1 && (ch <= 0x1f || ch == 0x7f)) {
-			gc.data.data[0] = '^';
-			gc.data.data[1] = (ch == 0x7f) ? '?' : ch|0x40;
-			gc.data.size = gc.data.have = 2;
-			gc.data.width = 2;
-		} else
-			utf8_copy(&gc.data, ud);
-		screen_write_cell(&ctx, &gc);
 	}
+	status_prompt_redraw_quote(c, pcursor, &ctx, offset, pwidth, &width,
+	    &gc);
 
 finished:
 	screen_write_stop(&ctx);
@@ -1274,7 +1311,6 @@ status_prompt_key(struct client *c, key_code key)
 	key &= ~KEYC_MASK_FLAGS;
 
 	if (c->prompt_flags & (PROMPT_SINGLE|PROMPT_QUOTENEXT)) {
-		c->prompt_flags &= ~PROMPT_QUOTENEXT;
 		if ((key & KEYC_MASK_KEY) == KEYC_BSPACE)
 			key = 0x7f;
 		else if ((key & KEYC_MASK_KEY) > 0x7f) {
@@ -1283,6 +1319,7 @@ status_prompt_key(struct client *c, key_code key)
 			key &= KEYC_MASK_KEY;
 		} else
 			key &= (key & KEYC_CTRL) ? 0x1f : KEYC_MASK_KEY;
+		c->prompt_flags &= ~PROMPT_QUOTENEXT;
 		goto append_key;
 	}