Merge branch 'lt/rev-list-interactive'

* lt/rev-list-interactive:
  Fix parent rewriting in --early-output
  revision walker: mini clean-up
  Enhance --early-output format
  Add "--early-output" log flag for interactive GUI use
  Simplify topo-sort logic

builtin-fmt-merge-msg.c

@@ -176,7 +176,7 @@ static void shortlog(const char *name, unsigned char *sha1,
 	struct commit *commit;
 	struct object *branch;
 	struct list subjects = { NULL, NULL, 0, 0 };
-	int flags = UNINTERESTING | TREECHANGE | SEEN | SHOWN | ADDED;
+	int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 
 	branch = deref_tag(parse_object(sha1), sha1_to_hex(sha1), 40);
 	if (!branch || branch->type != OBJ_COMMIT)

builtin-log.c

@@ -77,11 +77,134 @@ static void cmd_log_init(int argc, const char **argv, const char *prefix,
 	}
 }
 
+/*
+ * This gives a rough estimate for how many commits we
+ * will print out in the list.
+ */
+static int estimate_commit_count(struct rev_info *rev, struct commit_list *list)
+{
+	int n = 0;
+
+	while (list) {
+		struct commit *commit = list->item;
+		unsigned int flags = commit->object.flags;
+		list = list->next;
+		if (!(flags & (TREESAME | UNINTERESTING)))
+			n++;
+	}
+	return n;
+}
+
+static void show_early_header(struct rev_info *rev, const char *stage, int nr)
+{
+	if (rev->shown_one) {
+		rev->shown_one = 0;
+		if (rev->commit_format != CMIT_FMT_ONELINE)
+			putchar(rev->diffopt.line_termination);
+	}
+	printf("Final output: %d %s\n", nr, stage);
+}
+
+struct itimerval early_output_timer;
+
+static void log_show_early(struct rev_info *revs, struct commit_list *list)
+{
+	int i = revs->early_output;
+	int show_header = 1;
+
+	sort_in_topological_order(&list, revs->lifo);
+	while (list && i) {
+		struct commit *commit = list->item;
+		switch (simplify_commit(revs, commit)) {
+		case commit_show:
+			if (show_header) {
+				int n = estimate_commit_count(revs, list);
+				show_early_header(revs, "incomplete", n);
+				show_header = 0;
+			}
+			log_tree_commit(revs, commit);
+			i--;
+			break;
+		case commit_ignore:
+			break;
+		case commit_error:
+			return;
+		}
+		list = list->next;
+	}
+
+	/* Did we already get enough commits for the early output? */
+	if (!i)
+		return;
+
+	/*
+	 * ..if no, then repeat it twice a second until we
+	 * do.
+	 *
+	 * NOTE! We don't use "it_interval", because if the
+	 * reader isn't listening, we want our output to be
+	 * throttled by the writing, and not have the timer
+	 * trigger every second even if we're blocked on a
+	 * reader!
+	 */
+	early_output_timer.it_value.tv_sec = 0;
+	early_output_timer.it_value.tv_usec = 500000;
+	setitimer(ITIMER_REAL, &early_output_timer, NULL);
+}
+
+static void early_output(int signal)
+{
+	show_early_output = log_show_early;
+}
+
+static void setup_early_output(struct rev_info *rev)
+{
+	struct sigaction sa;
+
+	/*
+	 * Set up the signal handler, minimally intrusively:
+	 * we only set a single volatile integer word (not
+	 * using sigatomic_t - trying to avoid unnecessary
+	 * system dependencies and headers), and using
+	 * SA_RESTART.
+	 */
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = early_output;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = SA_RESTART;
+	sigaction(SIGALRM, &sa, NULL);
+
+	/*
+	 * If we can get the whole output in less than a
+	 * tenth of a second, don't even bother doing the
+	 * early-output thing..
+	 *
+	 * This is a one-time-only trigger.
+	 */
+	early_output_timer.it_value.tv_sec = 0;
+	early_output_timer.it_value.tv_usec = 100000;
+	setitimer(ITIMER_REAL, &early_output_timer, NULL);
+}
+
+static void finish_early_output(struct rev_info *rev)
+{
+	int n = estimate_commit_count(rev, rev->commits);
+	signal(SIGALRM, SIG_IGN);
+	show_early_header(rev, "done", n);
+}
+
 static int cmd_log_walk(struct rev_info *rev)
 {
 	struct commit *commit;
 
+	if (rev->early_output)
+		setup_early_output(rev);
+
 	prepare_revision_walk(rev);
+
+	if (rev->early_output)
+		finish_early_output(rev);
+
 	while ((commit = get_revision(rev)) != NULL) {
 		log_tree_commit(rev, commit);
 		if (!rev->reflog_info) {

builtin-rev-list.c

@@ -153,7 +153,7 @@ static int count_distance(struct commit_list *entry)
 
 		if (commit->object.flags & (UNINTERESTING | COUNTED))
 			break;
-		if (!revs.prune_fn || (commit->object.flags & TREECHANGE))
+		if (!(commit->object.flags & TREESAME))
 			nr++;
 		commit->object.flags |= COUNTED;
 		p = commit->parents;
@@ -209,7 +209,7 @@ static inline int halfway(struct commit_list *p, int nr)
 	/*
 	 * Don't short-cut something we are not going to return!
 	 */
-	if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
+	if (p->item->object.flags & TREESAME)
 		return 0;
 	if (DEBUG_BISECT)
 		return 0;
@@ -245,7 +245,7 @@ static void show_list(const char *debug, int counted, int nr,
 		char *ep, *sp;
 
 		fprintf(stderr, "%c%c%c ",
-			(flags & TREECHANGE) ? 'T' : ' ',
+			(flags & TREESAME) ? ' ' : 'T',
 			(flags & UNINTERESTING) ? 'U' : ' ',
 			(flags & COUNTED) ? 'C' : ' ');
 		if (commit->util)
@@ -279,7 +279,7 @@ static struct commit_list *best_bisection(struct commit_list *list, int nr)
 		int distance;
 		unsigned flags = p->item->object.flags;
 
-		if (revs.prune_fn && !(flags & TREECHANGE))
+		if (flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -319,7 +319,7 @@ static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
 		int distance;
 		unsigned flags = p->item->object.flags;
 
-		if (revs.prune_fn && !(flags & TREECHANGE))
+		if (flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -373,7 +373,7 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 		p->item->util = &weights[n++];
 		switch (count_interesting_parents(commit)) {
 		case 0:
-			if (!revs.prune_fn || (flags & TREECHANGE)) {
+			if (!(flags & TREESAME)) {
 				weight_set(p, 1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -446,7 +446,7 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 			 * add one for p itself if p is to be counted,
 			 * otherwise inherit it from q directly.
 			 */
-			if (!revs.prune_fn || (flags & TREECHANGE)) {
+			if (!(flags & TREESAME)) {
 				weight_set(p, weight(q)+1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -493,7 +493,7 @@ static struct commit_list *find_bisection(struct commit_list *list,
 			continue;
 		p->next = last;
 		last = p;
-		if (!revs.prune_fn || (flags & TREECHANGE))
+		if (!(flags & TREESAME))
 			nr++;
 		on_list++;
 	}