Merge pull request #1108 from libgit2/ahead-behind-count

Add API to calculate ahead/behind count

include/git2.h

@@ -23,6 +23,7 @@
 #include "git2/repository.h"
 #include "git2/revwalk.h"
 #include "git2/merge.h"
+#include "git2/graph.h"
 #include "git2/refs.h"
 #include "git2/reflog.h"
 #include "git2/revparse.h"

include/git2/graph.h

+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git_graph_h__
+#define INCLUDE_git_graph_h__
+
+#include "common.h"
+#include "types.h"
+#include "oid.h"
+
+/**
+ * @file git2/graph.h
+ * @brief Git graph traversal routines
+ * @defgroup git_revwalk Git graph traversal routines
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Count the number of unique commits between two commit objects
+ *
+ * @param ahead number of commits, starting at `one`, unique from commits in `two`
+ * @param behind number of commits, starting at `two`, unique from commits in `one`
+ * @param repo the repository where the commits exist
+ * @param one one of the commits
+ * @param two the other commit
+ */
+GIT_EXTERN(int) git_graph_ahead_behind(size_t *ahead, size_t *behind, git_repository *repo, const git_oid *one, const git_oid *two);
+
+/** @} */
+GIT_END_DECL
+#endif

src/commit_list.c

@@ -127,7 +127,7 @@ static int commit_quick_parse(git_revwalk *walk, git_commit_list_node *commit, g
 		if (git_oid_fromstr(&oid, (char *)buffer + strlen("parent ")) < 0)
 			return -1;
 
-		commit->parents[i] = commit_lookup(walk, &oid);
+		commit->parents[i] = git_revwalk__commit_lookup(walk, &oid);
 		if (commit->parents[i] == NULL)
 			return -1;
 
@@ -181,9 +181,13 @@ int git_commit_list_parse(git_revwalk *walk, git_commit_list_node *commit)
 
 	if ((error = git_odb_read(&obj, walk->odb, &commit->oid)) < 0)
 		return error;
-	assert(obj->raw.type == GIT_OBJ_COMMIT);
 
-	error = commit_quick_parse(walk, commit, &obj->raw);
+	if (obj->raw.type != GIT_OBJ_COMMIT) {
+		giterr_set(GITERR_INVALID, "Object is no commit object");
+		error = -1;
+	} else
+		error = commit_quick_parse(walk, commit, &obj->raw);
+
 	git_odb_object_free(obj);
 	return error;
 }

src/graph.c

+
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "revwalk.h"
+#include "merge.h"
+#include "git2/graph.h"
+
+static int ahead_behind(git_commit_list_node *one, git_commit_list_node *two,
+	size_t *ahead, size_t *behind)
+{
+	git_commit_list_node *commit;
+	git_pqueue pq;
+	int i;
+	*ahead = 0;
+	*behind = 0;
+
+	if (git_pqueue_init(&pq, 2, git_commit_list_time_cmp) < 0)
+		return -1;
+	if (git_pqueue_insert(&pq, one) < 0)
+		return -1;
+	if (git_pqueue_insert(&pq, two) < 0)
+		return -1;
+
+	while ((commit = git_pqueue_pop(&pq)) != NULL) {
+		if (commit->flags & RESULT ||
+			(commit->flags & (PARENT1 | PARENT2)) == (PARENT1 | PARENT2))
+			continue;
+		else if (commit->flags & PARENT1)
+			(*behind)++;
+		else if (commit->flags & PARENT2)
+			(*ahead)++;
+
+		for (i = 0; i < commit->out_degree; i++) {
+			git_commit_list_node *p = commit->parents[i];
+			if (git_pqueue_insert(&pq, p) < 0)
+				return -1;
+		}
+		commit->flags |= RESULT;
+	}
+
+	return 0;
+}
+
+int git_graph_ahead_behind(size_t *ahead, size_t *behind, git_repository *repo,
+	const git_oid *one, const git_oid *two)
+{
+	git_revwalk *walk;
+	git_vector list;
+	struct git_commit_list *result = NULL;
+	git_commit_list_node *commit1, *commit2;
+	void *contents[1];
+
+	if (git_revwalk_new(&walk, repo) < 0)
+		return -1;
+
+	commit2 = git_revwalk__commit_lookup(walk, two);
+	if (commit2 == NULL)
+		goto on_error;
+
+	/* This is just one value, so we can do it on the stack */
+	memset(&list, 0x0, sizeof(git_vector));
+	contents[0] = commit2;
+	list.length = 1;
+	list.contents = contents;
+
+	commit1 = git_revwalk__commit_lookup(walk, one);
+	if (commit1 == NULL)
+		goto on_error;
+
+	if (git_merge__bases_many(&result, walk, commit1, &list) < 0)
+		goto on_error;
+	if (ahead_behind(commit1, commit2, ahead, behind) < 0)
+		goto on_error;
+
+	if (!result) {
+		git_revwalk_free(walk);
+		return GIT_ENOTFOUND;
+	}
+
+	git_commit_list_free(&result);
+	git_revwalk_free(walk);
+
+	return 0;
+
+on_error:
+	git_revwalk_free(walk);
+	return -1;
+}

src/merge.c

@@ -71,14 +71,14 @@ int git_merge_base_many(git_oid *out, git_repository *repo, const git_oid input_
 		goto cleanup;
 
 	for (i = 1; i < length; i++) {
-		commit = commit_lookup(walk, &input_array[i]);
+		commit = git_revwalk__commit_lookup(walk, &input_array[i]);
 		if (commit == NULL)
 			goto cleanup;
 
 		git_vector_insert(&list, commit);
 	}
 
-	commit = commit_lookup(walk, &input_array[0]);
+	commit = git_revwalk__commit_lookup(walk, &input_array[0]);
 	if (commit == NULL)
 		goto cleanup;
 
@@ -112,7 +112,7 @@ int git_merge_base(git_oid *out, git_repository *repo, const git_oid *one, const
 	if (git_revwalk_new(&walk, repo) < 0)
 		return -1;
 
-	commit = commit_lookup(walk, two);
+	commit = git_revwalk__commit_lookup(walk, two);
 	if (commit == NULL)
 		goto on_error;
 
@@ -122,7 +122,7 @@ int git_merge_base(git_oid *out, git_repository *repo, const git_oid *one, const
 	list.length = 1;
 	list.contents = contents;
 
-	commit = commit_lookup(walk, one);
+	commit = git_revwalk__commit_lookup(walk, one);
 	if (commit == NULL)
 		goto on_error;
 
@@ -241,4 +241,3 @@ int git_merge__bases_many(git_commit_list **out, git_revwalk *walk, git_commit_l
 	*out = result;
 	return 0;
 }
-

src/revwalk.c

@@ -15,7 +15,8 @@
 
 #include <regex.h>
 
-git_commit_list_node *commit_lookup(git_revwalk *walk, const git_oid *oid)
+git_commit_list_node *git_revwalk__commit_lookup(
+	git_revwalk *walk, const git_oid *oid)
 {
 	git_commit_list_node *commit;
 	khiter_t pos;
@@ -101,7 +102,7 @@ static int push_commit(git_revwalk *walk, const git_oid *oid, int uninteresting)
 		return -1;
 	}
 
-	commit = commit_lookup(walk, oid);
+	commit = git_revwalk__commit_lookup(walk, oid);
 	if (commit == NULL)
 		return -1; /* error already reported by failed lookup */
 

src/revwalk.h

@@ -39,6 +39,6 @@ struct git_revwalk {
 	git_vector twos;
 };
 
-git_commit_list_node *commit_lookup(git_revwalk *walk, const git_oid *oid);
+git_commit_list_node *git_revwalk__commit_lookup(git_revwalk *walk, const git_oid *oid);
 
 #endif

tests-clar/resources/twowaymerge.git/HEAD

+ref: refs/heads/master

tests-clar/resources/twowaymerge.git/config

+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+	ignorecase = true

tests-clar/resources/twowaymerge.git/description

+Unnamed repository; edit this file 'description' to name the repository.

tests-clar/resources/twowaymerge.git/info/exclude

+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~

tests-clar/resources/twowaymerge.git/refs/heads/first-branch

+2224e191514cb4bd8c566d80dac22dfcb1e9bb83

tests-clar/resources/twowaymerge.git/refs/heads/master

+1c30b88f5f3ee66d78df6520a7de9e89b890818b

tests-clar/resources/twowaymerge.git/refs/heads/second-branch

+9b219343610c88a1187c996d0dc58330b55cee28

tests-clar/revwalk/mergebase.c

@@ -3,10 +3,12 @@
 #include <stdarg.h>
 
 static git_repository *_repo;
+static git_repository *_repo2;
 
 void test_revwalk_mergebase__initialize(void)
 {
 	cl_git_pass(git_repository_open(&_repo, cl_fixture("testrepo.git")));
+	cl_git_pass(git_repository_open(&_repo2, cl_fixture("twowaymerge.git")));
 }
 
 void test_revwalk_mergebase__cleanup(void)
@@ -18,6 +20,7 @@ void test_revwalk_mergebase__cleanup(void)
 void test_revwalk_mergebase__single1(void)
 {
 	git_oid result, one, two, expected;
+	size_t ahead, behind;
 
 	cl_git_pass(git_oid_fromstr(&one, "c47800c7266a2be04c571c04d5a6614691ea99bd "));
 	cl_git_pass(git_oid_fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
@@ -25,11 +28,20 @@ void test_revwalk_mergebase__single1(void)
 
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert(git_oid_cmp(&result, &expected) == 0);
+
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &one, &two));
+	cl_assert_equal_i(ahead, 2);
+	cl_assert_equal_i(behind, 1);
+
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &two, &one));
+	cl_assert_equal_i(ahead,  1);
+	cl_assert_equal_i(behind,  2);
 }
 
 void test_revwalk_mergebase__single2(void)
 {
 	git_oid result, one, two, expected;
+	size_t ahead, behind;
 
 	cl_git_pass(git_oid_fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af"));
 	cl_git_pass(git_oid_fromstr(&two, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
@@ -37,11 +49,20 @@ void test_revwalk_mergebase__single2(void)
 
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert(git_oid_cmp(&result, &expected) == 0);
+
+	cl_git_pass(git_graph_ahead_behind( &ahead, &behind, _repo, &one, &two));
+	cl_assert_equal_i(ahead,  4);
+	cl_assert_equal_i(behind,  1);
+
+	cl_git_pass(git_graph_ahead_behind( &ahead, &behind, _repo, &two, &one));
+	cl_assert_equal_i(ahead,  1);
+	cl_assert_equal_i(behind,  4);
 }
 
 void test_revwalk_mergebase__merged_branch(void)
 {
 	git_oid result, one, two, expected;
+	size_t ahead, behind;
 
 	cl_git_pass(git_oid_fromstr(&one, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
 	cl_git_pass(git_oid_fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
@@ -52,11 +73,38 @@ void test_revwalk_mergebase__merged_branch(void)
 
 	cl_git_pass(git_merge_base(&result, _repo, &two, &one));
 	cl_assert(git_oid_cmp(&result, &expected) == 0);
+
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &one, &two));
+	cl_assert_equal_i(ahead,  0);
+	cl_assert_equal_i(behind,  3);
+
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &two, &one));
+	cl_assert_equal_i(ahead,  3);
+	cl_assert_equal_i(behind,  0);
+}
+
+void test_revwalk_mergebase__two_way_merge(void)
+{
+	git_oid one, two;
+	size_t ahead, behind;
+
+	cl_git_pass(git_oid_fromstr(&one, "9b219343610c88a1187c996d0dc58330b55cee28"));
+	cl_git_pass(git_oid_fromstr(&two, "a953a018c5b10b20c86e69fef55ebc8ad4c5a417"));
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo2, &one, &two));
+
+	cl_assert_equal_i(ahead,  2);
+	cl_assert_equal_i(behind,  8);
+
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo2, &two, &one));
+
+	cl_assert_equal_i(ahead,  8);
+	cl_assert_equal_i(behind,  2);
 }
 
 void test_revwalk_mergebase__no_common_ancestor_returns_ENOTFOUND(void)
 {
 	git_oid result, one, two;
+	size_t ahead, behind;
 	int error;
 
 	cl_git_pass(git_oid_fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af"));
@@ -66,6 +114,11 @@ void test_revwalk_mergebase__no_common_ancestor_returns_ENOTFOUND(void)
 	cl_git_fail(error);
 
 	cl_assert_equal_i(GIT_ENOTFOUND, error);
+
+	cl_git_fail(git_graph_ahead_behind(&ahead, &behind, _repo, &one, &two));
+	cl_git_fail(error);
+
+	cl_assert_equal_i(GIT_ENOTFOUND, error);
 }
 
 void test_revwalk_mergebase__no_off_by_one_missing(void)
@@ -143,7 +196,7 @@ void test_revwalk_mergebase__many_merge_branch(void)
 }
 
 /*
- * $ git log --graph --all
+ * testrepo.git $ git log --graph --all
  * * commit 763d71aadf09a7951596c9746c024e7eece7c7af
  * | Author: nulltoken <emeric.fermas@gmail.com>
  * | Date:   Sun Oct 9 12:54:47 2011 +0200
@@ -222,3 +275,104 @@ void test_revwalk_mergebase__many_merge_branch(void)
  * 
  *       packed commit one
  */
+
+/*
+ * twowaymerge.git $ git log --graph --all
+ * *   commit 9b219343610c88a1187c996d0dc58330b55cee28
+ * |\  Merge: c37a783 2224e19
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:31:04 2012 -0800
+ * | | 
+ * | |     Merge branch 'first-branch' into second-branch
+ * | |   
+ * | * commit 2224e191514cb4bd8c566d80dac22dfcb1e9bb83
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:28:51 2012 -0800
+ * | | 
+ * | |     j
+ * | |   
+ * | * commit a41a49f8f5cd9b6cb14a076bf8394881ed0b4d19
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:28:39 2012 -0800
+ * | | 
+ * | |     i
+ * | |   
+ * | * commit 82bf9a1a10a4b25c1f14c9607b60970705e92545
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:28:28 2012 -0800
+ * | | 
+ * | |     h
+ * | |   
+ * * | commit c37a783c20d92ac92362a78a32860f7eebf938ef
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:30:57 2012 -0800
+ * | | 
+ * | |     n
+ * | |   
+ * * | commit 8b82fb1794cb1c8c7f172ec730a4c2db0ae3e650
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:30:43 2012 -0800
+ * | | 
+ * | |     m
+ * | |   
+ * * | commit 6ab5d28acbf3c3bdff276f7ccfdf29c1520e542f
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:30:38 2012 -0800
+ * | | 
+ * | |     l
+ * | |   
+ * * | commit 7b8c336c45fc6895c1c60827260fe5d798e5d247
+ * | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | Date:   Tue Nov 27 20:30:24 2012 -0800
+ * | | 
+ * | |     k
+ * | |     
+ * | | * commit 1c30b88f5f3ee66d78df6520a7de9e89b890818b
+ * | | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | | Date:   Tue Nov 27 20:28:10 2012 -0800
+ * | | | 
+ * | | |     e
+ * | | |    
+ * | | * commit 42b7311aa626e712891940c1ec5d5cba201946a4
+ * | | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | | Date:   Tue Nov 27 20:28:06 2012 -0800
+ * | | | 
+ * | | |     d
+ * | | |      
+ * | | *   commit a953a018c5b10b20c86e69fef55ebc8ad4c5a417
+ * | | |\  Merge: bd1732c cdf97fd
+ * | | |/  Author: Scott J. Goldman <scottjg@github.com>
+ * | |/|   Date:   Tue Nov 27 20:26:43 2012 -0800
+ * | | |   
+ * | | |       Merge branch 'first-branch'
+ * | | |    
+ * | * | commit cdf97fd3bb48eb3827638bb33d208f5fd32d0aa6
+ * | | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | | Date:   Tue Nov 27 20:24:46 2012 -0800
+ * | | | 
+ * | | |     g
+ * | | |    
+ * | * | commit ef0488f0b722f0be8bcb90a7730ac7efafd1d694
+ * | | | Author: Scott J. Goldman <scottjg@github.com>
+ * | | | Date:   Tue Nov 27 20:24:39 2012 -0800
+ * | | | 
+ * | | |     f
+ * | | |    
+ * | | * commit bd1732c43c68d712ad09e1d872b9be6d4b9efdc4
+ * | |/  Author: Scott J. Goldman <scottjg@github.com>
+ * | |   Date:   Tue Nov 27 17:43:58 2012 -0800
+ * | |   
+ * | |       c
+ * | |   
+ * | * commit 0c8a3f1f3d5f421cf83048c7c73ee3b55a5e0f29
+ * |/  Author: Scott J. Goldman <scottjg@github.com>
+ * |   Date:   Tue Nov 27 17:43:48 2012 -0800
+ * |   
+ * |       b
+ * |  
+ * * commit 1f4c0311a24b63f6fc209a59a1e404942d4a5006
+ *   Author: Scott J. Goldman <scottjg@github.com>
+ *   Date:   Tue Nov 27 17:43:41 2012 -0800
+ *
+ *       a
+ */