grafts: make the structure self-contained and opaque

In order to increase maintainability in the future, we should try to
make structures as self-contained and opaque to its users as possible.
Thus it is probably not a good idea to just typedef `git_graftmap` to
`git_oidmap`, as that will make it a lot harder in the future to extend
the API in the future, if this need ever arises.

Refactor the code to instead declare a real structure `git_grafts`,
which is completely opaque to its callers.

src/commit.c

@@ -22,7 +22,7 @@
 #include "object.h"
 #include "array.h"
 #include "oidarray.h"
-#include "graft.h"
+#include "grafts.h"
 
 void git_commit__free(void *_commit)
 {
@@ -504,7 +504,7 @@ int git_commit__parse_ext(git_commit *commit, git_odb_object *odb_obj, unsigned
 		return error;
 
 	/* Perform necessary grafts */
-	if (git__graft_for_oid(&graft, repo->grafts, git_odb_object_id(odb_obj)) != GIT_ENOTFOUND) {
+	if (git_grafts_get(&graft, repo->grafts, git_odb_object_id(odb_obj)) != GIT_ENOTFOUND) {
 		size_t idx;
 		git_oid *oid;
 		git_array_clear(commit->parent_ids);

src/graft.c → src/grafts.c

@@ -5,9 +5,53 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "graft.h"
+#include "grafts.h"
 
-int git__graft_register(git_graftmap *grafts, const git_oid *oid, git_array_oid_t parents)
+struct git_grafts {
+	/* Map of `git_commit_graft`s */
+	git_oidmap *commits;
+};
+
+int git_grafts_new(git_grafts **out)
+{
+	git_grafts *grafts;
+
+	grafts = git__calloc(1, sizeof(*grafts));
+	GIT_ERROR_CHECK_ALLOC(grafts);
+
+	if ((git_oidmap_new(&grafts->commits)) < 0) {
+		git__free(grafts);
+		return -1;
+	}
+
+	*out = grafts;
+	return 0;
+}
+
+void git_grafts_free(git_grafts *grafts)
+{
+	if (!grafts)
+		return;
+	git_grafts_clear(grafts);
+	git_oidmap_free(grafts->commits);
+	git__free(grafts);
+}
+
+void git_grafts_clear(git_grafts *grafts)
+{
+	git_commit_graft *graft;
+
+	assert(grafts);
+
+	git_oidmap_foreach_value(grafts->commits, graft, {
+		git__free(graft->parents.ptr);
+		git__free(graft);
+	});
+
+	git_oidmap_clear(grafts->commits);
+}
+
+int git_grafts_add(git_grafts *grafts, const git_oid *oid, git_array_oid_t parents)
 {
 	git_commit_graft *graft;
 	git_oid *parent_oid;
@@ -28,7 +72,7 @@ int git__graft_register(git_graftmap *grafts, const git_oid *oid, git_array_oid_
 	}
 	git_oid_cpy(&graft->oid, oid);
 
-	if ((error = git_oidmap_set(grafts, &graft->oid, graft)) < 0)
+	if ((error = git_oidmap_set(grafts->commits, &graft->oid, graft)) < 0)
 		goto cleanup;
 
 	return 0;
@@ -39,17 +83,17 @@ cleanup:
 	return error;
 }
 
-int git__graft_unregister(git_graftmap *grafts, const git_oid *oid)
+int git_grafts_remove(git_grafts *grafts, const git_oid *oid)
 {
 	git_commit_graft *graft;
 	int error;
 
 	assert(grafts && oid);
 
-	if ((graft = git_oidmap_get(grafts, oid)) == NULL)
+	if ((graft = git_oidmap_get(grafts->commits, oid)) == NULL)
 		return GIT_ENOTFOUND;
 
-	if ((error = git_oidmap_delete(grafts, oid)) < 0)
+	if ((error = git_oidmap_delete(grafts->commits, oid)) < 0)
 		return error;
 
 	git__free(graft);
@@ -57,24 +101,15 @@ int git__graft_unregister(git_graftmap *grafts, const git_oid *oid)
 	return 0;
 }
 
-void git__graft_clear(git_graftmap *grafts)
-{
-	git_commit_graft *graft;
-
-	assert(grafts);
-
-	git_oidmap_foreach_value(grafts, graft, {
-		git__free(graft->parents.ptr);
-		git__free(graft);
-	});
-
-	git_oidmap_clear(grafts);
-}
-
-int git__graft_for_oid(git_commit_graft **out, git_graftmap *grafts, const git_oid *oid)
+int git_grafts_get(git_commit_graft **out, git_grafts *grafts, const git_oid *oid)
 {
 	assert(out && grafts && oid);
-	if ((*out = git_oidmap_get(grafts, oid)) == NULL)
+	if ((*out = git_oidmap_get(grafts->commits, oid)) == NULL)
 		return GIT_ENOTFOUND;
 	return 0;
 }
+
+size_t git_grafts_size(git_grafts *grafts)
+{
+	return git_oidmap_size(grafts->commits);
+}

src/graft.h → src/grafts.h

@@ -17,13 +17,15 @@ typedef struct {
 	git_array_oid_t parents;
 } git_commit_graft;
 
-/* A special type of git_oidmap with git_commit_grafts as values */
-typedef git_oidmap git_graftmap;
+typedef struct git_grafts git_grafts;
 
-int git__graft_register(git_graftmap *grafts, const git_oid *oid, git_array_oid_t parents);
-int git__graft_unregister(git_graftmap *grafts, const git_oid *oid);
-void git__graft_clear(git_graftmap *grafts);
+int git_grafts_new(git_grafts **out);
+void git_grafts_free(git_grafts *grafts);
+void git_grafts_clear(git_grafts *grafts);
 
-int git__graft_for_oid(git_commit_graft **out, git_graftmap *grafts, const git_oid *oid);
+int git_grafts_add(git_grafts *grafts, const git_oid *oid, git_array_oid_t parents);
+int git_grafts_remove(git_grafts *grafts, const git_oid *oid);
+int git_grafts_get(git_commit_graft **out, git_grafts *grafts, const git_oid *oid);
+size_t git_grafts_size(git_grafts *grafts);
 
 #endif

src/repository.c

@@ -147,10 +147,7 @@ int git_repository__cleanup(git_repository *repo)
 	git_repository_submodule_cache_clear(repo);
 	git_cache_clear(&repo->objects);
 	git_attr_cache_flush(repo);
-
-	git__graft_clear(repo->grafts);
-	git_oidmap_free(repo->grafts);
-
+	git_grafts_free(repo->grafts);
 	git_array_clear(repo->shallow_oids);
 
 	set_config(repo, NULL);
@@ -259,7 +256,7 @@ static git_repository *repository_alloc(void)
 	/* set all the entries in the configmap cache to `unset` */
 	git_repository__configmap_lookup_cache_clear(repo);
 
-	if (git_oidmap_new(&repo->grafts) < 0)
+	if (git_grafts_new(&repo->grafts) < 0)
 		goto on_error;
 
 	return repo;
@@ -610,9 +607,8 @@ static int load_grafts(git_repository *repo)
 	if (error < 0)
 		goto cleanup;
 
-	if (updated) {
-		git__graft_clear(repo->grafts);
-	}
+	if (updated)
+		git_grafts_clear(repo->grafts);
 
 	dup_contents.ptr = contents.ptr;
 	git_buf_foreach_line(line_start, line_end, line_num, &dup_contents) {
@@ -638,7 +634,7 @@ static int load_grafts(git_repository *repo)
 			}
 		}
 
-		if (git__graft_register(repo->grafts, &graft_oid, parents) < 0) {
+		if (git_grafts_add(repo->grafts, &graft_oid, parents) < 0) {
 			git_error_set(GIT_ERROR_REPOSITORY, "Invalid graft at line %d", line_num);
 			error = -1;
 			goto cleanup;
@@ -668,9 +664,8 @@ static int load_shallow(git_repository *repo)
 	}
 
 	git_array_foreach(roots, i, graft_oid) {
-		if ((error = git__graft_register(repo->grafts, graft_oid, parents)) < 0) {
+		if ((error = git_grafts_add(repo->grafts, graft_oid, parents)) < 0)
 			return error;
-		}
 	}
 	return 0;
 }

src/repository.h

@@ -24,7 +24,7 @@
 #include "attrcache.h"
 #include "submodule.h"
 #include "diff_driver.h"
-#include "graft.h"
+#include "grafts.h"
 #include "oidarray.h"
 
 #define DOT_GIT ".git"
@@ -154,7 +154,7 @@ struct git_repository {
 
 	unsigned int lru_counter;
 
-	git_graftmap *grafts;
+	git_grafts *grafts;
 	git_oid graft_checksum;
 
 	git_oid shallow_checksum;

tests/grafts/basic.c

 #include "clar_libgit2.h"
 
 #include "futils.h"
-#include "graft.h"
+#include "grafts.h"
 
 static git_repository *g_repo;
 
@@ -17,29 +17,28 @@ void test_grafts_basic__cleanup(void)
 
 void test_grafts_basic__graft_add(void)
 {
+	git_array_oid_t parents = GIT_ARRAY_INIT;
 	git_oid oid_src, *oid1;
 	git_commit_graft *graft;
-	git_graftmap *grafts;
-	git_array_oid_t parents = GIT_ARRAY_INIT;
+	git_grafts *grafts;
 
-	cl_git_pass(git_oidmap_new(&grafts));
+	cl_git_pass(git_grafts_new(&grafts));
 
 	cl_assert(oid1 = git_array_alloc(parents));
 	cl_git_pass(git_oid_fromstr(&oid_src, "2f3053cbff8a4ca2f0666de364ddb734a28a31a9"));
 	git_oid_cpy(oid1, &oid_src);
 
 	git_oid_fromstr(&oid_src, "f503807ffa920e407a600cfaee96b7152259acc7");
-	cl_git_pass(git__graft_register(grafts, &oid_src, parents));
+	cl_git_pass(git_grafts_add(grafts, &oid_src, parents));
 	git_array_clear(parents);
 
-	cl_assert_equal_i(1, git_oidmap_size(grafts));
-	cl_git_pass(git__graft_for_oid(&graft, grafts, &oid_src));
+	cl_assert_equal_i(1, git_grafts_size(grafts));
+	cl_git_pass(git_grafts_get(&graft, grafts, &oid_src));
 	cl_assert_equal_s("f503807ffa920e407a600cfaee96b7152259acc7", git_oid_tostr_s(&graft->oid));
 	cl_assert_equal_i(1, git_array_size(graft->parents));
 	cl_assert_equal_s("2f3053cbff8a4ca2f0666de364ddb734a28a31a9", git_oid_tostr_s(git_array_get(graft->parents, 0)));
 
-	git__graft_clear(grafts);
-	git_oidmap_free(grafts);
+	git_grafts_free(grafts);
 }
 
 void test_grafts_basic__grafted_revwalk(void)