This reimplements log view reloading (Ctrl-L), logging of a parent
path (Backspace), and the toggle to show commits on branches (B).

The idea is to reuse the existing log view and change its state, instead
of allocating a new view with a new state and replacing the existing view.

Fixes a segfault that occurs when a parent path is logged with Backspace:

  tog tree -r got.git -c 0.44
  pick tog/tog.c
  'l'
  Backspace
  -> tog will segfault

This segfault is due to s->thread_arg.graph being NULL.

The first change in this diff is a partial fix. The log thread should always
check the 'quit' flag as soon as it wakes from sleep. Otherwise it could try
to load more commits after waking up and before checking the 'quit' flag.
It will then attempt to load commits with a NULL commit graph pointer.

This partial fix by itself is not sufficient to fix the crash, since we'll
now see a bus error in the main thread, instead of a NULL deref in the
log thread. The remainder of the patch fixes this bus error.

ok?

diff f039bcf33a8f964e16c59e2e66675bb6bb481658 c367f73d9195bfdbb50c5b566cea3b63f2e59f68
blob - 7c2c3668d66487cfb8b0e14d90d5e39d59115c9d
blob + 09b2f62935b8f75f2000a46ffd82c9df8323cc0d
--- tog/tog.c
+++ tog/tog.c
@@ -2026,6 +2026,8 @@ log_thread(void *arg)
 				if (errcode)
 					err = got_error_set_errno(errcode,
 					    "pthread_cond_wait");
+				if (*a->quit)
+					done = 1;
 			}
 		}
 
@@ -2348,11 +2350,9 @@ input_log_view(struct tog_view **new_view, struct tog_
 {
 	const struct got_error *err = NULL;
 	struct tog_log_view_state *s = &view->state.log;
-	char *parent_path, *in_repo_path = NULL;
-	struct tog_view *diff_view = NULL, *tree_view = NULL, *lv = NULL;
+	struct tog_view *diff_view = NULL, *tree_view = NULL;
 	struct tog_view *ref_view = NULL;
 	int begin_x = 0;
-	struct got_object_id *start_id;
 
 	switch (ch) {
 	case 'q':
@@ -2473,83 +2473,54 @@ input_log_view(struct tog_view **new_view, struct tog_
 			*new_view = tree_view;
 		break;
 	case KEY_BACKSPACE:
-		if (got_path_cmp(s->in_repo_path, "/",
-		    strlen(s->in_repo_path), 1) == 0)
-			break;
-		err = got_path_dirname(&parent_path, s->in_repo_path);
-		if (err)
-			return err;
-		err = stop_log_thread(s);
-		if (err) {
-			free(parent_path);
-			return err;
-		}
-		lv = view_open(view->nlines, view->ncols,
-		    view->begin_y, view->begin_x, TOG_VIEW_LOG);
-		if (lv == NULL) {
-			free(parent_path);
-			return got_error_from_errno("view_open");
-		}
-		err = open_log_view(lv, s->start_id, s->repo, s->head_ref_name,
-		    parent_path, s->log_branches);
-		free(parent_path);
-		if (err)
-			return err;;
-		view->focussed = 0;
-		lv->focussed = 1;
-		if (view_is_parent_view(view))
-			*new_view = lv;
-		else
-			view_set_child(view->parent, lv);
-		break;
 	case CTRL('l'):
-		err = stop_log_thread(s);
-		if (err)
-			return err;
-		lv = view_open(view->nlines, view->ncols,
-		    view->begin_y, view->begin_x, TOG_VIEW_LOG);
-		if (lv == NULL)
-			return got_error_from_errno("view_open");
-		err = got_repo_match_object_id(&start_id, NULL,
-		    s->head_ref_name ? s->head_ref_name : GOT_REF_HEAD,
-		    GOT_OBJ_TYPE_COMMIT, 1, s->repo);
-		if (err) {
-			view_close(lv);
-			return err;
-		}
-		in_repo_path = strdup(s->in_repo_path);
-		if (in_repo_path == NULL) {
-			free(start_id);
-			view_close(lv);
-			return got_error_from_errno("strdup");
-		}
-		err = open_log_view(lv, start_id, s->repo, s->head_ref_name,
-		    in_repo_path, s->log_branches);
-		if (err) {
-			free(start_id);
-			view_close(lv);
-			return err;;
-		}
-		view->dying = 1;
-		*new_view = lv;
-		break;
 	case 'B':
-		s->log_branches = !s->log_branches;
+		if (ch == KEY_BACKSPACE &&
+		    got_path_is_root_dir(s->in_repo_path))
+			break;
 		err = stop_log_thread(s);
 		if (err)
 			return err;
-		lv = view_open(view->nlines, view->ncols,
-		    view->begin_y, view->begin_x, TOG_VIEW_LOG);
-		if (lv == NULL)
-			return got_error_from_errno("view_open");
-		err = open_log_view(lv, s->start_id, s->repo,
-		    s->head_ref_name, s->in_repo_path, s->log_branches);
-		if (err) {
-			view_close(lv);
-			return err;;
-		}
-		view->dying = 1;
-		*new_view = lv;
+		if (ch == KEY_BACKSPACE) {
+			char *parent_path;
+			err = got_path_dirname(&parent_path, s->in_repo_path);
+			if (err)
+				return err;
+			free(s->in_repo_path);
+			s->in_repo_path = parent_path;
+			s->thread_args.in_repo_path = s->in_repo_path;
+		} else if (ch == CTRL('l')) {
+			struct got_object_id *start_id;
+			err = got_repo_match_object_id(&start_id, NULL,
+			    s->head_ref_name ? s->head_ref_name : GOT_REF_HEAD,
+			    GOT_OBJ_TYPE_COMMIT, 1, s->repo);
+			if (err)
+				return err;
+			free(s->start_id);
+			s->start_id = start_id;
+			s->thread_args.start_id = s->start_id;
+		} else /* 'B' */
+			s->log_branches = !s->log_branches;
+
+		err = got_repo_open(&s->thread_args.repo,
+		    got_repo_get_path(s->repo), NULL);
+		if (err)
+			return err;
+		err = got_commit_graph_open(&s->thread_args.graph,
+		    s->in_repo_path, !s->log_branches);
+		if (err)
+			return err;
+		err = got_commit_graph_iter_start(s->thread_args.graph,
+		    s->start_id, s->repo, NULL, NULL);
+		if (err)
+			return err;
+		free_commits(&s->commits);
+		s->first_displayed_entry = NULL;
+		s->last_displayed_entry = NULL;
+		s->selected_entry = NULL;
+		s->thread_args.log_complete = 0;
+		s->quit = 0;
+		s->thread_args.commits_needed = view->nlines;
 		break;
 	case 'r':
 		if (view_is_parent_view(view))