Merge pull request #3921 from libgit2/cmn/walk-limit-enough

Improve revision walk preparation logic

CHANGELOG.md

@@ -15,6 +15,8 @@ v0.24 + 1
 
 * Support for reading and writing git index v4 files
 
+* Improve the performance of the revwalk and bring us closer to git's code.
+
 ### API additions
 
 * You can now get the user-agent used by libgit2 using the

include/git2/revwalk.h

@@ -25,17 +25,15 @@ GIT_BEGIN_DECL
  */
 typedef enum {
 	/**
-	 * Sort the repository contents in no particular ordering;
-	 * this sorting is arbitrary, implementation-specific
-	 * and subject to change at any time.
+	 * Sort the output with the same default time-order method from git.
 	 * This is the default sorting for new walkers.
 	 */
 	GIT_SORT_NONE = 0,
 
 	/**
-	 * Sort the repository contents in topological order
-	 * (parents before children); this sorting mode
-	 * can be combined with time sorting.
+	 * Sort the repository contents in topological order (parents before
+	 * children); this sorting mode can be combined with time sorting to
+	 * produce git's "time-order".
 	 */
 	GIT_SORT_TOPOLOGICAL = 1 << 0,
 

src/commit_list.c

@@ -13,10 +13,15 @@
 
 int git_commit_list_time_cmp(const void *a, const void *b)
 {
-	const git_commit_list_node *commit_a = a;
-	const git_commit_list_node *commit_b = b;
+	int64_t time_a = ((git_commit_list_node *) a)->time;
+	int64_t time_b = ((git_commit_list_node *) b)->time;
 
-	return (commit_a->time < commit_b->time);
+	if (time_a < time_b)
+		return 1;
+	if (time_a > time_b)
+		return -1;
+
+	return 0;
 }
 
 git_commit_list *git_commit_list_insert(git_commit_list_node *item, git_commit_list **list_p)

src/commit_list.h

@@ -28,6 +28,7 @@ typedef struct git_commit_list_node {
 			 uninteresting:1,
 			 topo_delay:1,
 			 parsed:1,
+			 added:1,
 			 flags : FLAG_BITS;
 
 	unsigned short in_degree;

src/pqueue.c

@@ -93,7 +93,7 @@ int git_pqueue_insert(git_pqueue *pq, void *item)
 		(void)git_pqueue_pop(pq);
 	}
 
-	if (!(error = git_vector_insert(pq, item)))
+	if (!(error = git_vector_insert(pq, item)) && pq->_cmp)
 		pqueue_up(pq, pq->length - 1);
 
 	return error;
@@ -101,9 +101,15 @@ int git_pqueue_insert(git_pqueue *pq, void *item)
 
 void *git_pqueue_pop(git_pqueue *pq)
 {
-	void *rval = git_pqueue_get(pq, 0);
+	void *rval;
 
-	if (git_pqueue_size(pq) > 1) {
+	if (!pq->_cmp) {
+		rval = git_vector_last(pq);
+	} else {
+		rval = git_pqueue_get(pq, 0);
+	}
+
+	if (git_pqueue_size(pq) > 1 && pq->_cmp) {
 		/* move last item to top of heap, shrink, and push item down */
 		pq->contents[0] = git_vector_last(pq);
 		git_vector_pop(pq);

src/pqueue.h

@@ -35,6 +35,7 @@ extern int git_pqueue_init(
 #define git_pqueue_clear git_vector_clear
 #define git_pqueue_size  git_vector_length
 #define git_pqueue_get   git_vector_get
+#define git_pqueue_reverse git_vector_reverse
 
 /**
  * Insert a new item into the queue

src/rebase.c

@@ -586,7 +586,7 @@ static int rebase_init_operations(
 		(error = git_revwalk_hide(revwalk, git_annotated_commit_id(upstream))) < 0)
 		goto done;
 
-	git_revwalk_sorting(revwalk, GIT_SORT_REVERSE | GIT_SORT_TIME);
+	git_revwalk_sorting(revwalk, GIT_SORT_REVERSE);
 
 	while ((error = git_revwalk_next(&id, revwalk)) == 0) {
 		if ((error = git_commit_lookup(&commit, repo, &id)) < 0)

src/vector.c

@@ -401,3 +401,19 @@ int git_vector_verify_sorted(const git_vector *v)
 
 	return 0;
 }
+
+void git_vector_reverse(git_vector *v)
+{
+	size_t a, b;
+
+	a = 0;
+	b = v->length - 1;
+
+	while (a < b) {
+		void *tmp = v->contents[a];
+		v->contents[a] = v->contents[b];
+		v->contents[b] = tmp;
+		a++;
+		b--;
+	}
+}

src/vector.h

@@ -118,4 +118,9 @@ GIT_INLINE(void) git_vector_set_cmp(git_vector *v, git_vector_cmp cmp)
 /* Just use this in tests, not for realz. returns -1 if not sorted */
 int git_vector_verify_sorted(const git_vector *v);
 
+/**
+ * Reverse the vector in-place.
+ */
+void git_vector_reverse(git_vector *v);
+
 #endif

tests/core/vector.c

@@ -376,3 +376,32 @@ void test_core_vector__grow_and_shrink(void)
 
 	git_vector_free(&x);
 }
+
+void test_core_vector__reverse(void)
+{
+	git_vector v = GIT_VECTOR_INIT;
+	size_t i;
+
+	void *in1[] = {(void *) 0x0, (void *) 0x1, (void *) 0x2, (void *) 0x3};
+	void *out1[] = {(void *) 0x3, (void *) 0x2, (void *) 0x1, (void *) 0x0};
+
+	void *in2[] = {(void *) 0x0, (void *) 0x1, (void *) 0x2, (void *) 0x3, (void *) 0x4};
+	void *out2[] = {(void *) 0x4, (void *) 0x3, (void *) 0x2, (void *) 0x1, (void *) 0x0};
+
+	for (i = 0; i < 4; i++)
+		cl_git_pass(git_vector_insert(&v, in1[i]));
+
+	git_vector_reverse(&v);
+
+	for (i = 0; i < 4; i++)
+		cl_assert_equal_p(out1[i], git_vector_get(&v, i));
+
+	git_vector_clear(&v);
+	for (i = 0; i < 5; i++)
+		cl_git_pass(git_vector_insert(&v, in2[i]));
+
+	git_vector_reverse(&v);
+
+	for (i = 0; i < 5; i++)
+		cl_assert_equal_p(out2[i], git_vector_get(&v, i));
+}

tests/odb/foreach.c

@@ -28,8 +28,8 @@ static int foreach_cb(const git_oid *oid, void *data)
 
 /*
  * $ git --git-dir tests/resources/testrepo.git count-objects --verbose
- * count: 47
- * size: 4
+ * count: 60
+ * size: 240
  * in-pack: 1640
  * packs: 3
  * size-pack: 425
@@ -44,7 +44,7 @@ void test_odb_foreach__foreach(void)
 	git_repository_odb(&_odb, _repo);
 
 	cl_git_pass(git_odb_foreach(_odb, foreach_cb, &nobj));
-	cl_assert_equal_i(47 + 1640, nobj); /* count + in-pack */
+	cl_assert_equal_i(60 + 1640, nobj); /* count + in-pack */
 }
 
 void test_odb_foreach__one_pack(void)
@@ -118,7 +118,7 @@ void test_odb_foreach__files_in_objects_dir(void)
 
 	cl_git_pass(git_repository_odb(&odb, repo));
 	cl_git_pass(git_odb_foreach(odb, foreach_cb, &nobj));
-	cl_assert_equal_i(47 + 1640, nobj); /* count + in-pack */
+	cl_assert_equal_i(60 + 1640, nobj); /* count + in-pack */
 
 	git_odb_free(odb);
 	git_repository_free(repo);

tests/revwalk/basic.c

@@ -38,8 +38,9 @@ static const int commit_sorting_time_reverse[][6] = {
 	{4, 5, 2, 1, 3, 0}
 };
 
+/* This is specified unsorted, so both combinations are possible */
 static const int commit_sorting_segment[][6] = {
-	{1, 2, -1, -1, -1, -1}
+	{1, 2, -1, -1, -1, -1}, {2, 1, -1, -1, -1, -1}
 };
 
 #define commit_count 6
@@ -155,9 +156,8 @@ void test_revwalk_basic__glob_heads(void)
 
 	cl_git_pass(git_revwalk_push_glob(_walk, "heads"));
 
-	while (git_revwalk_next(&oid, _walk) == 0) {
+	while (git_revwalk_next(&oid, _walk) == 0)
 		i++;
-	}
 
 	/* git log --branches --oneline | wc -l => 14 */
 	cl_assert_equal_i(i, 14);
@@ -338,7 +338,7 @@ void test_revwalk_basic__push_range(void)
 	git_revwalk_reset(_walk);
 	git_revwalk_sorting(_walk, 0);
 	cl_git_pass(git_revwalk_push_range(_walk, "9fd738e~2..9fd738e"));
-	cl_git_pass(test_walk_only(_walk, commit_sorting_segment, 1));
+	cl_git_pass(test_walk_only(_walk, commit_sorting_segment, 2));
 }
 
 void test_revwalk_basic__push_mixed(void)
@@ -473,3 +473,51 @@ void test_revwalk_basic__big_timestamp(void)
 	git_signature_free(sig);
 
 }
+
+/* Ensure that we correctly hide a commit that is (timewise) older
+ * than the commits that we are showing.
+ *
+ * % git rev-list 8e73b76..bd75801
+ * bd758010071961f28336333bc41e9c64c9a64866
+ */
+void test_revwalk_basic__old_hidden_commit_one(void)
+{
+	git_oid new_id, old_id, oid;
+
+	revwalk_basic_setup_walk("testrepo.git");
+
+	cl_git_pass(git_oid_fromstr(&new_id, "bd758010071961f28336333bc41e9c64c9a64866"));
+	cl_git_pass(git_revwalk_push(_walk, &new_id));
+
+	cl_git_pass(git_oid_fromstr(&old_id, "8e73b769e97678d684b809b163bebdae2911720f"));
+	cl_git_pass(git_revwalk_hide(_walk, &old_id));
+
+	cl_git_pass(git_revwalk_next(&oid, _walk));
+	cl_assert(!git_oid_streq(&oid, "bd758010071961f28336333bc41e9c64c9a64866"));
+
+	cl_git_fail_with(GIT_ITEROVER, git_revwalk_next(&oid, _walk));
+}
+
+/* Ensure that we correctly hide a commit that is (timewise) older
+ * than the commits that we are showing.
+ *
+ * % git rev-list bd75801 ^b91e763
+ * bd758010071961f28336333bc41e9c64c9a64866
+ */
+void test_revwalk_basic__old_hidden_commit_two(void)
+{
+	git_oid new_id, old_id, oid;
+
+	revwalk_basic_setup_walk("testrepo.git");
+
+	cl_git_pass(git_oid_fromstr(&new_id, "bd758010071961f28336333bc41e9c64c9a64866"));
+	cl_git_pass(git_revwalk_push(_walk, &new_id));
+
+	cl_git_pass(git_oid_fromstr(&old_id, "b91e763008b10db366442469339f90a2b8400d0a"));
+	cl_git_pass(git_revwalk_hide(_walk, &old_id));
+
+	cl_git_pass(git_revwalk_next(&oid, _walk));
+	cl_assert(!git_oid_streq(&oid, "bd758010071961f28336333bc41e9c64c9a64866"));
+
+	cl_git_fail_with(GIT_ITEROVER, git_revwalk_next(&oid, _walk));
+}

tests/revwalk/hidecb.c

@@ -158,6 +158,7 @@ void test_revwalk_hidecb__hide_some_commits(void)
 
 	cl_git_pass(git_revwalk_new(&walk, _repo));
 	cl_git_pass(git_revwalk_push(walk, &_head_id));
+	git_revwalk_sorting(walk, GIT_SORT_TOPOLOGICAL);
 
 	/* Add hide callback */
 	cl_git_pass(git_revwalk_add_hide_cb(walk, hide_commit_cb, NULL));
@@ -182,6 +183,7 @@ void test_revwalk_hidecb__test_payload(void)
 
 	cl_git_pass(git_revwalk_new(&walk, _repo));
 	cl_git_pass(git_revwalk_push(walk, &_head_id));
+	git_revwalk_sorting(walk, GIT_SORT_TOPOLOGICAL);
 
 	/* Add hide callback, pass id of parent of initial commit as payload data */
 	cl_git_pass(git_revwalk_add_hide_cb(walk, hide_commit_use_payload_cb, &commit_ids[5]));

tests/revwalk/simplify.c

@@ -40,6 +40,7 @@ void test_revwalk_simplify__first_parent(void)
 
 	git_oid_fromstr(&id, commit_head);
 	cl_git_pass(git_revwalk_push(walk, &id));
+	git_revwalk_sorting(walk, GIT_SORT_TOPOLOGICAL);
 	git_revwalk_simplify_first_parent(walk);
 
 	i = 0;