[PATCH 2/7] add option to only visit the first parent of a equal tree merge

From

BLBernhard R. Link <brlink@debian.org>

Date

Nov 30, 2009, 14:44 UTC

Message-ID

<590501c88c7a7b4a7c0c29543775060d4b0e2316.1259524136.git.brlink@debian.org>

In-Reply-To

<cover.1259524136.git.brlink@debian.org>

TODO:
 - manpage updates
 - check interaction with some of the other options
---
 revision.c |   57 ++++++++++++++++++++++++++++++++++++++++++++++++---------
 revision.h |    1 +
 2 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/revision.c b/revision.c
index a8a3c3a..fb019d6 100644
--- a/revision.c
+++ b/revision.c
@@ -452,6 +452,7 @@ static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 	struct commit_list *parent = commit->parents;
 	unsigned left_flag;
 	struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
+	int first_parent_only;
 
 	if (commit->object.flags & ADDED)
 		return 0;
@@ -499,6 +500,21 @@ static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 
 	left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 
+	if (revs->first_parent_only)
+		first_parent_only = 1;
+	else if (revs->first_equal_tree_only && commit->parents) {
+		for (parent = commit->parents; parent; parent = parent->next) {
+			struct commit *p = parent->item;
+
+			if (parse_commit(p) < 0)
+				return -1;
+			if (p->tree != commit->tree)
+				break;
+		}
+		first_parent_only = !parent;
+	} else
+		first_parent_only = 0;
+
 	for (parent = commit->parents; parent; parent = parent->next) {
 		struct commit *p = parent->item;
 
@@ -511,7 +527,7 @@ static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 			p->object.flags |= SEEN;
 			insert_by_date_cached(p, list, cached_base, cache_ptr);
 		}
-		if (revs->first_parent_only)
+		if (first_parent_only)
 			break;
 	}
 	return 0;
@@ -1067,6 +1083,10 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->min_age = approxidate(arg + 8);
 	} else if (!strcmp(arg, "--first-parent")) {
 		revs->first_parent_only = 1;
+	} else if (!strcmp(arg, "--first-equal-tree-only")) {
+		revs->first_equal_tree_only = 1;
+	} else if (!strcmp(arg, "--all-equal-trees")) {
+		revs->first_equal_tree_only = 0;
 	} else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
 		init_reflog_walk(&revs->reflog_info);
 	} else if (!strcmp(arg, "--default")) {
@@ -1912,6 +1932,16 @@ static void create_boundary_commit_list(struct rev_info *revs)
 	sort_in_topological_order(&revs->commits, revs->lifo);
 }
 
+static inline void add_boundary_commit(struct rev_info *revs, struct commit *c) {
+	struct object *p = &c->object;
+
+	if (p->flags & (CHILD_SHOWN | SHOWN))
+		return;
+	p->flags |= CHILD_SHOWN;
+	gc_boundary(&revs->boundary_commits);
+	add_object_array(p, NULL, &revs->boundary_commits);
+}
+
 static struct commit *get_revision_internal(struct rev_info *revs)
 {
 	struct commit *c = NULL;
@@ -1987,16 +2017,25 @@ static struct commit *get_revision_internal(struct rev_info *revs)
 	 * 'c', we need to mark its parents that they could be boundaries.
 	 */
 
-	for (l = c->parents; l; l = l->next) {
-		struct object *p;
-		p = &(l->item->object);
-		if (p->flags & (CHILD_SHOWN | SHOWN))
-			continue;
-		p->flags |= CHILD_SHOWN;
-		gc_boundary(&revs->boundary_commits);
-		add_object_array(p, NULL, &revs->boundary_commits);
+	if (revs->first_equal_tree_only && c->parents) {
+		for (l = c->parents; l; l = l->next) {
+			struct commit *p = l->item;
+			parse_commit(p);
+			if (c->tree != p->tree)
+				break;
+		}
+		/* if all parents have the same tree as this node,
+		 * it's an equal tree merge, so ignore all but the
+		 * first parent */
+		if (!l) {
+			add_boundary_commit(revs, c->parents->item);
+			return c;
+		}
 	}
 
+	for (l = c->parents; l; l = l->next) {
+		add_boundary_commit(revs, l->item);
+	}
 	return c;
 }
 
diff --git a/revision.h b/revision.h
index d368003..7ac263c 100644
--- a/revision.h
+++ b/revision.h
@@ -64,6 +64,7 @@ struct rev_info {
 			reverse_output_stage:1,
 			cherry_pick:1,
 			bisect:1,
+			first_equal_tree_only:1,
 			first_parent_only:1;
 
 	/* Diff flags */