grafts: move refresh logic into grafts code

The refresh logic for both "normal" and shallow grafts are currently
part of the repository code and implemented twice. Unify them into the
grafts code by introducing two new functions to create grafts from a
file and to refresh a grafts structure.

src/grafts.c

@@ -7,12 +7,17 @@
 
 #include "grafts.h"
 
+#include "futils.h"
 #include "oidarray.h"
 #include "parse.h"
 
 struct git_grafts {
 	/* Map of `git_commit_graft`s */
 	git_oidmap *commits;
+
+	/* File backing the graft. NULL if it's an in-memory graft */
+	char *path;
+	git_oid path_checksum;
 };
 
 int git_grafts_new(git_grafts **out)
@@ -31,10 +36,32 @@ int git_grafts_new(git_grafts **out)
 	return 0;
 }
 
+int git_grafts_from_file(git_grafts **out, const char *path)
+{
+	git_grafts *grafts = NULL;
+	int error;
+
+	if ((error = git_grafts_new(&grafts)) < 0)
+		goto error;
+
+	grafts->path = git__strdup(path);
+	GIT_ERROR_CHECK_ALLOC(grafts->path);
+
+	if ((error = git_grafts_refresh(grafts)) < 0)
+		goto error;
+
+	*out = grafts;
+error:
+	if (error < 0)
+		git_grafts_free(grafts);
+	return error;
+}
+
 void git_grafts_free(git_grafts *grafts)
 {
 	if (!grafts)
 		return;
+	git__free(grafts->path);
 	git_grafts_clear(grafts);
 	git_oidmap_free(grafts->commits);
 	git__free(grafts);
@@ -54,6 +81,34 @@ void git_grafts_clear(git_grafts *grafts)
 	git_oidmap_clear(grafts->commits);
 }
 
+int git_grafts_refresh(git_grafts *grafts)
+{
+	git_buf contents = GIT_BUF_INIT;
+	int error, updated = 0;
+
+	assert(grafts);
+
+	if (!grafts->path)
+		return 0;
+
+	error = git_futils_readbuffer_updated(&contents, grafts->path,
+					      &grafts->path_checksum, &updated);
+	if (error < 0 || error == GIT_ENOTFOUND || !updated) {
+		if (error == GIT_ENOTFOUND) {
+			git_grafts_clear(grafts);
+			error = 0;
+		}
+		goto cleanup;
+	}
+
+	if ((error = git_grafts_parse(grafts, contents.ptr, contents.size)) < 0)
+		goto cleanup;
+
+cleanup:
+	git_buf_dispose(&contents);
+	return error;
+}
+
 int git_grafts_parse(git_grafts *grafts, const char *content, size_t contentlen)
 {
 	git_array_oid_t parents = GIT_ARRAY_INIT;

src/grafts.h

@@ -20,9 +20,11 @@ typedef struct {
 typedef struct git_grafts git_grafts;
 
 int git_grafts_new(git_grafts **out);
+int git_grafts_from_file(git_grafts **out, const char *path);
 void git_grafts_free(git_grafts *grafts);
 void git_grafts_clear(git_grafts *grafts);
 
+int git_grafts_refresh(git_grafts *grafts);
 int git_grafts_parse(git_grafts *grafts, const char *content, size_t contentlen);
 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);

src/repository.c

@@ -256,9 +256,6 @@ 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_grafts_new(&repo->grafts) < 0)
-		goto on_error;
-
 	return repo;
 
 on_error:
@@ -581,47 +578,23 @@ out:
 
 static int load_grafts(git_repository *repo)
 {
-	git_buf graft_path = GIT_BUF_INIT;
-	git_buf contents = GIT_BUF_INIT;
-	int error, updated;
-
-	if ((error = git_repository_item_path(&graft_path, repo, GIT_REPOSITORY_ITEM_INFO)) < 0)
-		return error;
-
-	if (git_buf_joinpath(&graft_path, graft_path.ptr, "grafts")) {
-		git_buf_dispose(&graft_path);
-		return error;
-	}
-
-	error = git_futils_readbuffer_updated(&contents, git_buf_cstr(&graft_path),
-					      &repo->graft_checksum, &updated);
-	if (error < 0 || error == GIT_ENOTFOUND || !updated) {
-		if (error == GIT_ENOTFOUND)
-			error = 0;
-		goto cleanup;
-	}
-
-	if ((error = git_grafts_parse(repo->grafts, contents.ptr, contents.size)) < 0)
-		goto cleanup;
+	git_buf path = GIT_BUF_INIT;
+	int error;
 
-cleanup:
-	git_buf_dispose(&contents);
-	git_buf_dispose(&graft_path);
+	if ((error = git_repository_item_path(&path, repo, GIT_REPOSITORY_ITEM_INFO)) < 0 ||
+	    (error = git_buf_joinpath(&path, path.ptr, "grafts")) < 0 ||
+	    (error = git_grafts_from_file(&repo->grafts, path.ptr)) < 0)
+		goto error;
 
-	return error;
-}
+	git_buf_clear(&path);
 
-static int load_shallow(git_repository *repo)
-{
-	git_oidarray roots;
-	int error;
+	if ((error = git_buf_joinpath(&path, repo->gitdir, "shallow")) < 0 ||
+	    (error = git_grafts_from_file(&repo->shallow_grafts, path.ptr)) < 0)
+		goto error;
 
-	/* Graft shallow roots */
-	if ((error = git_repository_shallow_roots(&roots, repo)) < 0)
+error:
+	git_buf_dispose(&path);
 	return error;
-
-	git_oidarray_free(&roots);
-	return 0;
 }
 
 int git_repository_open_bare(
@@ -916,9 +889,6 @@ int git_repository_open_ext(
 	if ((error = load_grafts(repo)) < 0)
 		goto cleanup;
 
-	if ((error = load_shallow(repo)) < 0)
-		goto cleanup;
-
 	if ((flags & GIT_REPOSITORY_OPEN_BARE) != 0)
 		repo->is_bare = 1;
 	else {
@@ -2956,27 +2926,14 @@ int git_repository_state_cleanup(git_repository *repo)
 int git_repository_shallow_roots(git_oidarray *out, git_repository *repo)
 {
 	git_buf path = GIT_BUF_INIT, contents = GIT_BUF_INIT;
-	int error, updated = 0;
+	int error;
 
 	assert(out && repo);
 
 	memset(out, 0, sizeof(*out));
 
-	if (!repo->shallow_grafts && (error = git_grafts_new(&repo->shallow_grafts)) < 0)
-		goto error;
-
-	if ((error = git_buf_joinpath(&path, repo->gitdir, "shallow")) < 0 ||
-	    (error = git_futils_readbuffer_updated(&contents, git_buf_cstr(&path),
-						   &repo->shallow_checksum, &updated)) < 0) {
-		if (error == GIT_ENOTFOUND)
-			error = 0;
-		goto error;
-	}
-
-	if (updated && (error = git_grafts_parse(repo->shallow_grafts, contents.ptr, contents.size)) < 0)
-		goto error;
-
-	if ((error = git_grafts_get_oids(out, repo->shallow_grafts)) < 0)
+	if ((error = git_grafts_refresh(repo->shallow_grafts)) < 0 ||
+	    (error = git_grafts_get_oids(out, repo->shallow_grafts)) < 0)
 		goto error;
 
 error:

src/repository.h

@@ -155,10 +155,7 @@ struct git_repository {
 	unsigned int lru_counter;
 
 	git_grafts *grafts;
-	git_oid graft_checksum;
-
 	git_grafts *shallow_grafts;
-	git_oid shallow_checksum;
 
 	git_atomic attr_session_key;