On Fri, Jul 01, 2022 at 03:15:31PM +1000, Mark Jamsek wrote:
> On 22-07-01 12:15am, Stefan Sperling wrote:
> > Make the diff algorithm used by 'tog diff' and 'tog blame' configurable.
> > This allows people (like me) who prefer slow and tidy Patience diffs over
> > quick and ugly Myers diffs to tell tog about this preference.
> > 
> > As a bonus, the diff algorithm can be toggled at run-time, in both the
> > diff view and the blame view, by pressing the A key.
> > 
> > ok?
> 
> Nice! Works as described.
> 
> ok with or without tiny nit below

Thanks!

The previous diff had a problem. When both a blame and a diff view were
displayed, and the diff algorithm was switched in one of the two views,
only the view which was processing input got updated. The other view was
now out of sync with the current diff algorithm setting.

The new patch below does not have this problem. If the diff algorithm is
changed in any view, all relevant views will be regenerated.

diff 4b752015b5208a96c2d1b6c1c6b8589884b8b2b6 026bef347ee0d2a3a411a47420b9aec1a00aec3e
commit - 4b752015b5208a96c2d1b6c1c6b8589884b8b2b6
commit + 026bef347ee0d2a3a411a47420b9aec1a00aec3e
blob - 728ba5ee9e20edbde20ed7f0c2ff1cbabad89c0b
blob + ed0412fd13daaa1ea18139730716db483ba49274
--- tog/tog.1
+++ tog/tog.1
@@ -295,6 +295,12 @@ Find the Nth previous line which matches the current s
 (default: 1).
 .It Cm w
 Toggle display of whitespace-only changes.
+.It Cm A
+Change the diff algorithm.
+Supported diff algorithms are Myers and Patience. 
+This is a global setting which also affects the
+.Cm blame
+view.
 .El
 .Pp
 The options for
@@ -379,6 +385,12 @@ Find the Nth next line which matches the current searc
 .It Cm N
 Find the Nth previous line which matches the current search pattern
 (default: 1).
+.It Cm A
+Change the diff algorithm.
+Supported diff algorithms are Myers and Patience. 
+This is a global setting which also affects the
+.Cm diff
+view.
 .El
 .Pp
 The options for
@@ -560,7 +572,15 @@ work tree, use the repository path associated with thi
 .El
 .El
 .Sh ENVIRONMENT
-.Bl -tag -width TOG_COLORS
+.Bl -tag -width TOG_DIFF_ALGORITHM
+.It Ev TOG_DIFF_ALGORITHM
+Determines the default diff algorithm used by
+.Nm .
+Valid values are
+.Dq patience
+and
+.Dq myers .
+If unset, the Myers diff algorithm will be used by default.
 .It Ev TOG_COLORS
 .Nm
 shows colorized output if this variable is set to a non-empty value.
blob - 800384dacf0faed4893832dd2760af45e28cb8c7
blob + 56481e67ad1e36e598bf01561c6b3ec76fea52c2
--- tog/tog.c
+++ tog/tog.c
@@ -136,6 +136,7 @@ STAILQ_HEAD(tog_colors, tog_color);
 
 static struct got_reflist_head tog_refs = TAILQ_HEAD_INITIALIZER(tog_refs);
 static struct got_reflist_object_id_map *tog_refs_idmap;
+static enum got_diff_algorithm tog_diff_algo = GOT_DIFF_ALGORITHM_MYERS;
 
 static const struct got_error *
 tog_ref_cmp_by_name(void *arg, int *cmp, struct got_reference *re1,
@@ -321,7 +322,6 @@ struct tog_diff_view_state {
 	int first_displayed_line;
 	int last_displayed_line;
 	int eof;
-	enum got_diff_algorithm diff_algo;
 	int diff_context;
 	int ignore_whitespace;
 	int force_text_diff;
@@ -544,6 +544,7 @@ struct tog_view {
 	const struct got_error *(*show)(struct tog_view *);
 	const struct got_error *(*input)(struct tog_view **,
 	    struct tog_view *, int);
+	const struct got_error *(*reset)(struct tog_view *);
 	const struct got_error *(*close)(struct tog_view *);
 
 	const struct got_error *(*search_start)(struct tog_view *);
@@ -567,6 +568,7 @@ static const struct got_error *open_diff_view(struct t
 static const struct got_error *show_diff_view(struct tog_view *);
 static const struct got_error *input_diff_view(struct tog_view **,
     struct tog_view *, int);
+static const struct got_error *reset_diff_view(struct tog_view *);
 static const struct got_error* close_diff_view(struct tog_view *);
 static const struct got_error *search_start_diff_view(struct tog_view *);
 static const struct got_error *search_next_diff_view(struct tog_view *);
@@ -586,6 +588,7 @@ static const struct got_error *open_blame_view(struct 
 static const struct got_error *show_blame_view(struct tog_view *);
 static const struct got_error *input_blame_view(struct tog_view **,
     struct tog_view *, int);
+static const struct got_error *reset_blame_view(struct tog_view *);
 static const struct got_error *close_blame_view(struct tog_view *);
 static const struct got_error *search_start_blame_view(struct tog_view *);
 static const struct got_error *search_next_blame_view(struct tog_view *);
@@ -651,7 +654,6 @@ tog_fatal_signal_received(void)
 	    tog_sigint_received || tog_sigint_received);
 }
 
-
 static const struct got_error *
 view_close(struct tog_view *view)
 {
@@ -1217,6 +1219,24 @@ view_input(struct tog_view **new, int *done, struct to
 		} else
 			err = view->input(new, view, ch);
 		break;
+	case 'A':
+		if (tog_diff_algo == GOT_DIFF_ALGORITHM_MYERS)
+			tog_diff_algo = GOT_DIFF_ALGORITHM_PATIENCE;
+		else
+			tog_diff_algo = GOT_DIFF_ALGORITHM_MYERS;
+		TAILQ_FOREACH(v, views, entry) {
+			if (v->reset) {
+				err = v->reset(v);
+				if (err)
+					return err;
+			}
+			if (v->child && v->child->reset) {
+				err = v->child->reset(v->child);
+				if (err)
+					return err;
+			}
+		}
+		break;
 	default:
 		err = view->input(new, view, ch);
 		break;
@@ -3966,13 +3986,13 @@ create_diff(struct tog_diff_view_state *s)
 	case GOT_OBJ_TYPE_BLOB:
 		err = got_diff_objects_as_blobs(&s->line_offsets, &s->nlines,
 		    s->f1, s->f2, s->fd1, s->fd2, s->id1, s->id2,
-		    s->label1, s->label2, s->diff_algo, s->diff_context,
+		    s->label1, s->label2, tog_diff_algo, s->diff_context,
 		    s->ignore_whitespace, s->force_text_diff, s->repo, s->f);
 		break;
 	case GOT_OBJ_TYPE_TREE:
 		err = got_diff_objects_as_trees(&s->line_offsets, &s->nlines,
 		    s->f1, s->f2, s->fd1, s->fd2, s->id1, s->id2, NULL, "", "",
-		    s->diff_algo, s->diff_context, s->ignore_whitespace,
+		    tog_diff_algo, s->diff_context, s->ignore_whitespace,
 		    s->force_text_diff, s->repo, s->f);
 		break;
 	case GOT_OBJ_TYPE_COMMIT: {
@@ -4008,7 +4028,7 @@ create_diff(struct tog_diff_view_state *s)
 
 		err = got_diff_objects_as_commits(&s->line_offsets, &s->nlines,
 		    s->f1, s->f2, s->fd1, s->fd2, s->id1, s->id2, NULL,
-		    s->diff_algo, s->diff_context, s->ignore_whitespace,
+		    tog_diff_algo, s->diff_context, s->ignore_whitespace,
 		    s->force_text_diff, s->repo, s->f);
 		break;
 	}
@@ -4219,7 +4239,6 @@ open_diff_view(struct tog_view *view, struct got_objec
 
 	s->first_displayed_line = 1;
 	s->last_displayed_line = view->nlines;
-	s->diff_algo = GOT_DIFF_ALGORITHM_MYERS;
 	s->diff_context = diff_context;
 	s->ignore_whitespace = ignore_whitespace;
 	s->force_text_diff = force_text_diff;
@@ -4273,6 +4292,7 @@ open_diff_view(struct tog_view *view, struct got_objec
 
 	view->show = show_diff_view;
 	view->input = input_diff_view;
+	view->reset = reset_diff_view;
 	view->close = close_diff_view;
 	view->search_start = search_start_diff_view;
 	view->search_next = search_next_diff_view;
@@ -4343,6 +4363,22 @@ set_selected_commit(struct tog_diff_view_state *s,
 }
 
 static const struct got_error *
+reset_diff_view(struct tog_view *view)
+{
+	struct tog_diff_view_state *s = &view->state.diff;
+
+	fprintf(stderr, "%s\n", __func__);
+
+	view->count = 0;
+	wclear(view->window);
+	s->first_displayed_line = 1;
+	s->last_displayed_line = view->nlines;
+	s->matched_line = 0;
+	diff_view_indicate_progress(view);
+	return create_diff(s);
+}
+
+static const struct got_error *
 input_diff_view(struct tog_view **new_view, struct tog_view *view, int ch)
 {
 	const struct got_error *err = NULL;
@@ -4381,13 +4417,7 @@ input_diff_view(struct tog_view **new_view, struct tog
 			s->force_text_diff = !s->force_text_diff;
 		if (ch == 'w')
 			s->ignore_whitespace = !s->ignore_whitespace;
-		wclear(view->window);
-		s->first_displayed_line = 1;
-		s->last_displayed_line = view->nlines;
-		s->matched_line = 0;
-		diff_view_indicate_progress(view);
-		err = create_diff(s);
-		view->count = 0;
+		err = reset_diff_view(view);
 		break;
 	case 'g':
 	case KEY_HOME:
@@ -4950,7 +4980,7 @@ blame_thread(void *arg)
 		goto done;
 
 	err = got_blame(ta->path, a->commit_id, ta->repo,
-	    GOT_DIFF_ALGORITHM_MYERS, blame_cb, ta->cb_args,
+	    tog_diff_algo, blame_cb, ta->cb_args,
 	    ta->cancel_cb, ta->cancel_arg, fd1, fd2, f1, f2);
 	if (err && err->code == GOT_ERR_CANCELLED)
 		err = NULL;
@@ -5225,6 +5255,7 @@ open_blame_view(struct tog_view *view, char *path,
 
 	view->show = show_blame_view;
 	view->input = input_blame_view;
+	view->reset = reset_blame_view;
 	view->close = close_blame_view;
 	view->search_start = search_start_blame_view;
 	view->search_next = search_next_blame_view;
@@ -5641,6 +5672,22 @@ input_blame_view(struct tog_view **new_view, struct to
 }
 
 static const struct got_error *
+reset_blame_view(struct tog_view *view)
+{
+	const struct got_error *err;
+	struct tog_blame_view_state *s = &view->state.blame;
+
+	fprintf(stderr, "%s\n", __func__);
+	view->count = 0;
+	s->done = 1;
+	err = stop_blame(&s->blame);
+	s->done = 0;
+	if (err)
+		return err;
+	return run_blame(view);
+}
+
+static const struct got_error *
 cmd_blame(int argc, char *argv[])
 {
 	const struct got_error *error;
@@ -7839,6 +7886,7 @@ main(int argc, char *argv[])
 	    { "version", no_argument, NULL, 'V' },
 	    { NULL, 0, NULL, 0}
 	};
+	char *diff_algo_str = NULL;
 
 	setlocale(LC_CTYPE, "");
 
@@ -7892,6 +7940,14 @@ main(int argc, char *argv[])
 		}
 	}
 
+	diff_algo_str = getenv("TOG_DIFF_ALGORITHM");
+	if (diff_algo_str) {
+		if (strcasecmp(diff_algo_str, "patience") == 0)
+			tog_diff_algo = GOT_DIFF_ALGORITHM_PATIENCE;
+		if (strcasecmp(diff_algo_str, "myers") == 0)
+			tog_diff_algo = GOT_DIFF_ALGORITHM_MYERS;
+	}
+
 	if (cmd == NULL) {
 		if (argc != 1)
 			usage(0, 1);