Rework how reference labels are rendered in the tog log view.

Draw reference labels and log message as separate strings. The previous
code contained calculations mixing variables which represent an amount
of wide characters in a string vs the display width of the string. We
can avoid such nonsense by keeping the strings separate, though we have
to be a bit careful about keeping horizontal scrolling intact.

Also fix a bug where we failed to account for reference labels while
setting view->maxx which made the $ key not scroll far enough.

ok?

diff 77fc0a255189c6c18e1ea0d6ea82ae1d0ddb4ea7 9bf6d2828e3118620e1be58bbed4fe5248b6a93a
commit - 77fc0a255189c6c18e1ea0d6ea82ae1d0ddb4ea7
commit + 9bf6d2828e3118620e1be58bbed4fe5248b6a93a
blob - 96f7de49f09ae8cf589aa33bf8856131995de5fb
blob + 2967045d820cd7a35bca8f83bb6ba88e886e81fe
--- tog/tog.c
+++ tog/tog.c
@@ -2407,11 +2407,10 @@ draw_commit(struct tog_view *view, struct got_commit_o
 	char *refs_str = NULL;
 	char *logmsg0 = NULL, *logmsg = NULL;
 	char *author = NULL;
-	wchar_t *wlogmsg = NULL, *wauthor = NULL;
-	int author_width, logmsg_width;
-	size_t wrefstr_len = 0;
+	wchar_t *wrefstr = NULL, *wlogmsg = NULL, *wauthor = NULL;
+	int author_width, refstr_width, logmsg_width;
 	char *newline, *line = NULL;
-	int col, limit, scrollx;
+	int col, limit, scrollx, logmsg_x;
 	const int avail = view->ncols;
 	struct tm tm;
 	time_t committer_time;
@@ -2497,57 +2496,70 @@ draw_commit(struct tog_view *view, struct got_commit_o
 	if (newline)
 		*newline = '\0';
 
+	limit = avail - col;
+	if (view->child && !view_is_hsplit_top(view) && limit > 0)
+		limit--;	/* for the border */
+
 	/* Prepend reference labels to log message if possible .*/
 	refs = got_reflist_object_id_map_lookup(tog_refs_idmap, id);
 	err = build_refs_str(&refs_str, refs, id, s->repo);
 	if (err)
 		goto done;
 	if (refs_str) {
-		char *newlogmsg;
-		wchar_t *ws;
+		char *rs;
 
-		/*
-		 * The length of this wide-char sub-string will be
-		 * needed later for colorization.
-		 */
-		err = mbs2ws(&ws, &wrefstr_len, refs_str);
-		if (err)
-			goto done;
-		free(ws);
-
-		wrefstr_len += 2; /* account for '[' and ']' */
-
-		if (asprintf(&newlogmsg, "[%s] %s", refs_str, logmsg) == -1) {
+		if (asprintf(&rs, "[%s]", refs_str) == -1) {
 			err = got_error_from_errno("asprintf");
 			goto done;
 		}
+		err = format_line(&wrefstr, &refstr_width,
+		    &scrollx, rs, view->x, limit, col, 1);
+		free(rs);
+		if (err)
+			goto done;
+		tc = get_color(&s->colors, TOG_COLOR_COMMIT);
+		if (tc)
+			wattr_on(view->window,
+			    COLOR_PAIR(tc->colorpair), NULL);
+		waddwstr(view->window, &wrefstr[scrollx]);
+		if (tc)
+			wattr_off(view->window,
+			    COLOR_PAIR(tc->colorpair), NULL);
+		col += MAX(refstr_width, 0);
+		if (col > avail)
+			goto done;
 
-		free(logmsg0);
-		logmsg0 = newlogmsg;
-		logmsg = logmsg0;
-	}
+		if (col < avail) {
+			waddch(view->window, ' ');
+			col++;
+		}
 
-	limit = avail - col;
-	if (view->child && !view_is_hsplit_top(view) && limit > 0)
-		limit--;	/* for the border */
-	err = format_line(&wlogmsg, &logmsg_width, &scrollx, logmsg, view->x,
+		if (refstr_width > 0)
+			logmsg_x = 0;
+		else {
+			int unscrolled_refstr_width;
+			size_t len = wcslen(wrefstr);
+
+			/*
+			 * No need to check for -1 return value here since
+			 * unprintables have been replaced by span_wline().
+			 */
+			unscrolled_refstr_width = wcswidth(wrefstr, len);
+			unscrolled_refstr_width += 1; /* trailing space */
+			logmsg_x = view->x - unscrolled_refstr_width;
+		}
+
+		limit = avail - col;
+		if (view->child && !view_is_hsplit_top(view) && limit > 0)
+			limit--;	/* for the border */
+	} else
+		logmsg_x = view->x;
+
+	err = format_line(&wlogmsg, &logmsg_width, &scrollx, logmsg, logmsg_x,
 	    limit, col, 1);
 	if (err)
 		goto done;
-	if (wrefstr_len > 0 && scrollx < wrefstr_len) {
-		tc = get_color(&s->colors, TOG_COLOR_COMMIT);
-		if (tc)
-			wattr_on(view->window,
-			    COLOR_PAIR(tc->colorpair), NULL);
-		waddnwstr(view->window, &wlogmsg[scrollx],
-		    MIN(logmsg_width, wrefstr_len - scrollx));
-		if (tc)
-			wattr_off(view->window,
-			    COLOR_PAIR(tc->colorpair), NULL);
-		if (col + MIN(logmsg_width, wrefstr_len - scrollx) < avail)
-			waddwstr(view->window, &wlogmsg[wrefstr_len]);
-	} else
-		waddwstr(view->window, &wlogmsg[scrollx]);
+	waddwstr(view->window, &wlogmsg[scrollx]);
 	col += MAX(logmsg_width, 0);
 	while (col < avail) {
 		waddch(view->window, ' ');
@@ -2556,6 +2568,7 @@ done:
 done:
 	free(logmsg0);
 	free(wlogmsg);
+	free(wrefstr);
 	free(refs_str);
 	free(author);
 	free(wauthor);
@@ -2762,19 +2775,19 @@ draw_commits(struct tog_view *view)
 	struct commit_queue_entry *entry = s->selected_entry;
 	int limit = view->nlines;
 	int width;
-	int ncommits, author_cols = 4;
+	int ncommits, author_cols = 4, refstr_cols;
 	char *id_str = NULL, *header = NULL, *ncommits_str = NULL;
 	char *refs_str = NULL;
 	wchar_t *wline;
 	struct tog_color *tc;
 	static const size_t date_display_cols = 12;
+	struct got_reflist_head *refs;
 
 	if (view_is_hsplit_top(view))
 		--limit;  /* account for border */
 
 	if (s->selected_entry &&
 	    !(view->searching && view->search_next_done == 0)) {
-		struct got_reflist_head *refs;
 		err = got_object_id_str(&id_str, s->selected_entry->id);
 		if (err)
 			return err;
@@ -2888,6 +2901,21 @@ draw_commits(struct tog_view *view)
 		free(author);
 		if (err)
 			goto done;
+		refs = got_reflist_object_id_map_lookup(tog_refs_idmap,
+		    entry->id);
+		err = build_refs_str(&refs_str, refs, entry->id, s->repo);
+		if (err)
+			goto done;
+		if (refs_str) {
+			wchar_t *ws;
+			err = format_line(&ws, &width, NULL, refs_str,
+			    0, INT_MAX, date_display_cols + author_cols, 0);
+			free(ws);
+			if (err)
+				goto done;
+			refstr_cols = width + 3; /* account for [ ] + space */
+		} else
+			refstr_cols = 0;
 		err = got_object_commit_get_logmsg(&msg0, c);
 		if (err)
 			goto done;
@@ -2897,10 +2925,10 @@ draw_commits(struct tog_view *view)
 		if ((eol = strchr(msg, '\n')))
 			*eol = '\0';
 		err = format_line(&wmsg, &width, NULL, msg, 0, INT_MAX,
-		    date_display_cols + author_cols, 0);
+		    date_display_cols + author_cols + refstr_cols, 0);
 		if (err)
 			goto done;
-		view->maxx = MAX(view->maxx, width);
+		view->maxx = MAX(view->maxx, width + refstr_cols);
 		free(msg0);
 		free(wmsg);
 		ncommits++;