From: Christian Weisgerber <naddy@mips.inka.de>
Subject: Re: tog: handle Home/End for log and diff views
To: Jasper Lievisse Adriaanse <j@jasper.la>
Cc: gameoftrees@openbsd.org
Date: Sat, 4 Sep 2021 12:33:40 +0200

Jasper Lievisse Adriaanse:

> The 'End' handling for the log view was the trickiest because of the
> way new commits are progressively discovered. I think the approach below
> might be the quickest way we currently can do.

Sorry for doing this so piecemeal, but I'd like to revise the jump
to the end, too:

> +	case 'G':
> +	case KEY_END: {
> +		/* We don't know yet how many commits, so we're forced to
> +		 * traverse them all. */
> +		while (1) {
> +			if (s->thread_args.log_complete)
> +				break;
> +
> +			s->thread_args.commits_needed++;
> +			trigger_log_thread(view, 1);
> +		}
> +
> +		log_scroll_down(view, s->commits.ncommits);

Since this doesn't account for the current position in the queue,
it is really an upper bound.  log_scroll_down(view, INT_MAX) would
do the same.  While traversing the queue is not a problem in practice,
it is inelegant.

> +		s->selected = MIN(view->nlines - 2, s->commits.ncommits - 1);
> +		select_commit(s);
> +		break;
> +	}

I would like to copy the approach from the tree and ref views:
Start at the tail and traverse backwards as far as required.
OK?

diff refs/heads/main refs/heads/tweak
blob - bca3ff788bde20700e3c2568236079a6d5be3970
blob + a61b2885188ca56c732c41d2f597ad00ab285533
--- tog/tog.c
+++ tog/tog.c
@@ -2387,7 +2387,8 @@ input_log_view(struct tog_view **new_view, struct tog_
 	struct tog_log_view_state *s = &view->state.log;
 	struct tog_view *diff_view = NULL, *tree_view = NULL;
 	struct tog_view *ref_view = NULL;
-	int begin_x = 0;
+	struct commit_queue_entry *entry;
+	int begin_x = 0, n;
 
 	if (s->thread_args.load_all) {
 		if (ch == KEY_BACKSPACE)
@@ -2459,8 +2460,16 @@ input_log_view(struct tog_view **new_view, struct tog_
 			return trigger_log_thread(view, 0);
 		}
 
-		log_scroll_down(view, s->commits.ncommits);
-		s->selected = MIN(view->nlines - 2, s->commits.ncommits - 1);
+		s->selected = 0;
+		entry = TAILQ_LAST(&s->commits.head, commit_queue_head);
+		for (n = 0; n < view->nlines - 1; n++) {
+			if (entry == NULL)
+				break;
+			s->first_displayed_entry = entry;
+			entry = TAILQ_PREV(entry, commit_queue_head, entry);
+		}
+		if (n > 0)
+			s->selected = n - 1;
 		select_commit(s);
 		break;
 	}

-- 
Christian "naddy" Weisgerber                          naddy@mips.inka.de