repo: load shallow roots

include/git2/repository.h

@@ -11,6 +11,7 @@
 #include "types.h"
 #include "oid.h"
 #include "buffer.h"
+#include "oidarray.h"
 
 /**
  * @file git2/repository.h
@@ -875,6 +876,17 @@ GIT_EXTERN(const char *) git_repository_get_namespace(git_repository *repo);
 GIT_EXTERN(int) git_repository_is_shallow(git_repository *repo);
 
 /**
+ * Determine the shallow roots of the repository
+ *
+ * This oidarray is owned by the library. Do not free it.
+ *
+ * @param out An array of shallow oids.
+ * @param repo The repository
+ * @return 0 on success, an error otherwise.
+ */
+GIT_EXTERN(int) git_repository_shallow_roots(git_oidarray *out, git_repository *repo);
+
+/**
  * Retrieve the configured identity to use for reflogs
  *
  * The memory is owned by the repository and must not be freed by the

src/repository.c

@@ -151,6 +151,8 @@ int git_repository__cleanup(git_repository *repo)
 	git__graft_clear(repo->grafts);
 	git_oidmap_free(repo->grafts);
 
+	git_array_clear(repo->shallow_oids);
+
 	set_config(repo, NULL);
 	set_index(repo, NULL);
 	set_odb(repo, NULL);
@@ -2978,6 +2980,79 @@ int git_repository_state_cleanup(git_repository *repo)
 	return git_repository__cleanup_files(repo, state_files, ARRAY_SIZE(state_files));
 }
 
+int git_repository__shallow_roots(git_array_oid_t *out, git_repository *repo)
+{
+	git_buf path = GIT_BUF_INIT;
+	git_buf contents = GIT_BUF_INIT;
+	int error, updated, line_num = 1;
+	char *line;
+	char *buffer;
+
+    assert(out && repo);
+
+	if ((error = git_buf_joinpath(&path, repo->gitdir, "shallow")) < 0)
+		return error;
+
+	error = git_futils_readbuffer_updated(&contents, git_buf_cstr(&path), &repo->shallow_checksum, &updated);
+	git_buf_dispose(&path);
+
+	if (error < 0 && error != GIT_ENOTFOUND)
+		return error;
+
+	/* cancel out GIT_ENOTFOUND */
+	git_error_clear();
+	error = 0;
+
+	if (!updated) {
+		*out = repo->shallow_oids;
+		goto cleanup;
+	}
+
+	git_array_clear(repo->shallow_oids);
+
+	buffer = contents.ptr;
+	while ((line = git__strsep(&buffer, "\n")) != NULL) {
+		git_oid *oid = git_array_alloc(repo->shallow_oids);
+
+		error = git_oid_fromstr(oid, line);
+		if (error < 0) {
+			git_error_set(GIT_ERROR_REPOSITORY, "Invalid OID at line %d", line_num);
+			git_array_clear(repo->shallow_oids);
+			error = -1;
+			goto cleanup;
+		}
+		++line_num;
+	}
+
+	if (*buffer) {
+		git_error_set(GIT_ERROR_REPOSITORY, "No EOL at line %d", line_num);
+		git_array_clear(repo->shallow_oids);
+		error = -1;
+		goto cleanup;
+	}
+
+	*out = repo->shallow_oids;
+
+cleanup:
+	git_buf_dispose(&contents);
+
+	return error;
+}
+
+int git_repository_shallow_roots(git_oidarray *out, git_repository *repo)
+{
+	int ret;
+	git_array_oid_t array = GIT_ARRAY_INIT;
+
+	assert(out);
+
+	ret = git_repository__shallow_roots(&array, repo);
+
+	git_oidarray__from_array(out, &array);
+
+	return ret;
+}
+
 int git_repository_is_shallow(git_repository *repo)
 {
 	git_buf path = GIT_BUF_INIT;

src/repository.h

@@ -25,6 +25,7 @@
 #include "submodule.h"
 #include "diff_driver.h"
 #include "graft.h"
+#include "oidarray.h"
 
 #define DOT_GIT ".git"
 #define GIT_DIR DOT_GIT "/"
@@ -156,6 +157,9 @@ struct git_repository {
 	git_graftmap *grafts;
 	git_oid graft_checksum;
 
+	git_oid shallow_checksum;
+	git_array_oid_t shallow_oids;
+
 	git_atomic attr_session_key;
 
 	git_configmap_value configmap_cache[GIT_CONFIGMAP_CACHE_MAX];
@@ -259,4 +263,6 @@ extern size_t git_repository__reserved_names_posix_len;
 bool git_repository__reserved_names(
 	git_buf **out, size_t *outlen, git_repository *repo, bool include_ntfs);
 
+int git_repository__shallow_roots(git_array_oid_t *out, git_repository *repo);
+
 #endif