thodg/libgit2/src/submodule.c

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• Hash : 428f1acf
  Author :
  Date : 2021-06-15T17:33:03
  

  submodule: git submodule dup out and source parameters have become mandatory.

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• src/submodule.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * 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 "submodule.h"
  
  #include "git2/config.h"
  #include "git2/sys/config.h"
  #include "git2/types.h"
  #include "git2/index.h"
  #include "buffer.h"
  #include "vector.h"
  #include "posix.h"
  #include "config_backend.h"
  #include "config.h"
  #include "repository.h"
  #include "tree.h"
  #include "iterator.h"
  #include "path.h"
  #include "index.h"
  #include "worktree.h"
  #include "clone.h"
  
  #define GIT_MODULES_FILE ".gitmodules"
  
  static git_configmap _sm_update_map[] = {
  	{GIT_CONFIGMAP_STRING, "checkout", GIT_SUBMODULE_UPDATE_CHECKOUT},
  	{GIT_CONFIGMAP_STRING, "rebase", GIT_SUBMODULE_UPDATE_REBASE},
  	{GIT_CONFIGMAP_STRING, "merge", GIT_SUBMODULE_UPDATE_MERGE},
  	{GIT_CONFIGMAP_STRING, "none", GIT_SUBMODULE_UPDATE_NONE},
  	{GIT_CONFIGMAP_FALSE, NULL, GIT_SUBMODULE_UPDATE_NONE},
  	{GIT_CONFIGMAP_TRUE, NULL, GIT_SUBMODULE_UPDATE_CHECKOUT},
  };
  
  static git_configmap _sm_ignore_map[] = {
  	{GIT_CONFIGMAP_STRING, "none", GIT_SUBMODULE_IGNORE_NONE},
  	{GIT_CONFIGMAP_STRING, "untracked", GIT_SUBMODULE_IGNORE_UNTRACKED},
  	{GIT_CONFIGMAP_STRING, "dirty", GIT_SUBMODULE_IGNORE_DIRTY},
  	{GIT_CONFIGMAP_STRING, "all", GIT_SUBMODULE_IGNORE_ALL},
  	{GIT_CONFIGMAP_FALSE, NULL, GIT_SUBMODULE_IGNORE_NONE},
  	{GIT_CONFIGMAP_TRUE, NULL, GIT_SUBMODULE_IGNORE_ALL},
  };
  
  static git_configmap _sm_recurse_map[] = {
  	{GIT_CONFIGMAP_STRING, "on-demand", GIT_SUBMODULE_RECURSE_ONDEMAND},
  	{GIT_CONFIGMAP_FALSE, NULL, GIT_SUBMODULE_RECURSE_NO},
  	{GIT_CONFIGMAP_TRUE, NULL, GIT_SUBMODULE_RECURSE_YES},
  };
  
  enum {
  	CACHE_OK = 0,
  	CACHE_REFRESH = 1,
  	CACHE_FLUSH = 2
  };
  enum {
  	GITMODULES_EXISTING = 0,
  	GITMODULES_CREATE = 1,
  };
  
  static int submodule_alloc(git_submodule **out, git_repository *repo, const char *name);
  static git_config_backend *open_gitmodules(git_repository *repo, int gitmod);
  static int gitmodules_snapshot(git_config **snap, git_repository *repo);
  static int get_url_base(git_buf *url, git_repository *repo);
  static int lookup_head_remote_key(git_buf *remote_key, git_repository *repo);
  static int lookup_default_remote(git_remote **remote, git_repository *repo);
  static int submodule_load_each(const git_config_entry *entry, void *payload);
  static int submodule_read_config(git_submodule *sm, git_config *cfg);
  static int submodule_load_from_wd_lite(git_submodule *);
  static void submodule_get_index_status(unsigned int *, git_submodule *);
  static void submodule_get_wd_status(unsigned int *, git_submodule *, git_repository *, git_submodule_ignore_t);
  static void submodule_update_from_index_entry(git_submodule *sm, const git_index_entry *ie);
  static void submodule_update_from_head_data(git_submodule *sm, mode_t mode, const git_oid *id);
  
  static int submodule_cmp(const void *a, const void *b)
  {
  	return strcmp(((git_submodule *)a)->name, ((git_submodule *)b)->name);
  }
  
  static int submodule_config_key_trunc_puts(git_buf *key, const char *suffix)
  {
  	ssize_t idx = git_buf_rfind(key, '.');
  	git_buf_truncate(key, (size_t)(idx + 1));
  	return git_buf_puts(key, suffix);
  }
  
  /*
   * PUBLIC APIS
   */
  
  static void submodule_set_lookup_error(int error, const char *name)
  {
  	if (!error)
  		return;
  
  	git_error_set(GIT_ERROR_SUBMODULE, (error == GIT_ENOTFOUND) ?
  		"no submodule named '%s'" :
  		"submodule '%s' has not been added yet", name);
  }
  
  typedef struct {
  	const char *path;
  	char *name;
  } fbp_data;
  
  static int find_by_path(const git_config_entry *entry, void *payload)
  {
  	fbp_data *data = payload;
  
  	if (!strcmp(entry->value, data->path)) {
  		const char *fdot, *ldot;
  		fdot = strchr(entry->name, '.');
  		ldot = strrchr(entry->name, '.');
  		data->name = git__strndup(fdot + 1, ldot - fdot - 1);
  		GIT_ERROR_CHECK_ALLOC(data->name);
  	}
  
  	return 0;
  }
  
  /*
   * Checks to see if the submodule shares its name with a file or directory that
   * already exists on the index. If so, the submodule cannot be added.
   */
  static int is_path_occupied(bool *occupied, git_repository *repo, const char *path)
  {
  	int error = 0;
  	git_index *index;
  	git_buf dir = GIT_BUF_INIT;
  	*occupied = false;
  
  	if ((error = git_repository_index__weakptr(&index, repo)) < 0)
  		goto out;
  
  	if ((error = git_index_find(NULL, index, path)) != GIT_ENOTFOUND) {
  		if (!error) {
  			git_error_set(GIT_ERROR_SUBMODULE,
  				"File '%s' already exists in the index", path);
  			*occupied = true;
  		}
  		goto out;
  	}
  
  	if ((error = git_buf_sets(&dir, path)) < 0)
  		goto out;
  
  	if ((error = git_path_to_dir(&dir)) < 0)
  		goto out;
  
  	if ((error = git_index_find_prefix(NULL, index, dir.ptr)) != GIT_ENOTFOUND) {
  		if (!error) {
  			git_error_set(GIT_ERROR_SUBMODULE,
  				"Directory '%s' already exists in the index", path);
  			*occupied = true;
  		}
  		goto out;
  	}
  
  	error = 0;
  
  out:
  	git_buf_dispose(&dir);
  	return error;
  }
  
  /**
   * Release the name map returned by 'load_submodule_names'.
   */
  static void free_submodule_names(git_strmap *names)
  {
  	const char *key;
  	char *value;
  
  	if (names == NULL)
  		return;
  
  	git_strmap_foreach(names, key, value, {
  		git__free((char *) key);
  		git__free(value);
  	});
  	git_strmap_free(names);
  
  	return;
  }
  
  /**
   * Map submodule paths to names.
   * TODO: for some use-cases, this might need case-folding on a
   * case-insensitive filesystem
   */
  static int load_submodule_names(git_strmap **out, git_repository *repo, git_config *cfg)
  {
  	const char *key = "submodule\\..*\\.path";
  	git_config_iterator *iter = NULL;
  	git_config_entry *entry;
  	git_buf buf = GIT_BUF_INIT;
  	git_strmap *names;
  	int isvalid, error;
  
  	*out = NULL;
  
  	if ((error = git_strmap_new(&names)) < 0)
  		goto out;
  
  	if ((error = git_config_iterator_glob_new(&iter, cfg, key)) < 0)
  		goto out;
  
  	while ((error = git_config_next(&entry, iter)) == 0) {
  		const char *fdot, *ldot;
  		fdot = strchr(entry->name, '.');
  		ldot = strrchr(entry->name, '.');
  
  		if (git_strmap_exists(names, entry->value)) {
  			git_error_set(GIT_ERROR_SUBMODULE,
  				   "duplicated submodule path '%s'", entry->value);
  			error = -1;
  			goto out;
  		}
  
  		git_buf_clear(&buf);
  		git_buf_put(&buf, fdot + 1, ldot - fdot - 1);
  		isvalid = git_submodule_name_is_valid(repo, buf.ptr, 0);
  		if (isvalid < 0) {
  			error = isvalid;
  			goto out;
  		}
  		if (!isvalid)
  			continue;
  
  		if ((error = git_strmap_set(names, git__strdup(entry->value), git_buf_detach(&buf))) < 0) {
  			git_error_set(GIT_ERROR_NOMEMORY, "error inserting submodule into hash table");
  			error = -1;
  			goto out;
  		}
  	}
  	if (error == GIT_ITEROVER)
  		error = 0;
  
  	*out = names;
  	names = NULL;
  
  out:
  	free_submodule_names(names);
  	git_buf_dispose(&buf);
  	git_config_iterator_free(iter);
  	return error;
  }
  
  int git_submodule_cache_init(git_strmap **out, git_repository *repo)
  {
  	int error = 0;
  	git_strmap *cache = NULL;
  	GIT_ASSERT_ARG(out);
  	GIT_ASSERT_ARG(repo);
  	if ((error = git_strmap_new(&cache)) < 0)
  		return error;
  	if ((error = git_submodule__map(repo, cache)) < 0) {
  		git_submodule_cache_free(cache);
  		return error;
  	}
  	*out = cache;
  	return error;
  }
  
  int git_submodule_cache_free(git_strmap *cache)
  {
  	git_submodule *sm = NULL;
  	if (cache == NULL)
  		return 0;
  	git_strmap_foreach_value(cache, sm, {
  		git_submodule_free(sm);
  	});
  	git_strmap_free(cache);
  	return 0;
  }
  
  int git_submodule_lookup(
  	git_submodule **out, /* NULL if user only wants to test existence */
  	git_repository *repo,
  	const char *name)    /* trailing slash is allowed */
  {
  	return git_submodule__lookup_with_cache(out, repo, name, repo->submodule_cache);
  }
  
  int git_submodule__lookup_with_cache(
  	git_submodule **out, /* NULL if user only wants to test existence */
  	git_repository *repo,
  	const char *name,    /* trailing slash is allowed */
  	git_strmap *cache)
  {
  	int error;
  	unsigned int location;
  	git_submodule *sm;
  
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(name);
  
  	if (repo->is_bare) {
  		git_error_set(GIT_ERROR_SUBMODULE, "cannot get submodules without a working tree");
  		return -1;
  	}
  
  	if (cache != NULL) {
  		if ((sm = git_strmap_get(cache, name)) != NULL) {
  			if (out) {
  				*out = sm;
  				GIT_REFCOUNT_INC(*out);
  			}
  			return 0;
  		}
  	}
  
  	if ((error = submodule_alloc(&sm, repo, name)) < 0)
  		return error;
  
  	if ((error = git_submodule_reload(sm, false)) < 0) {
  		git_submodule_free(sm);
  		return error;
  	}
  
  	if ((error = git_submodule_location(&location, sm)) < 0) {
  		git_submodule_free(sm);
  		return error;
  	}
  
  	/* If it's not configured or we're looking by path  */
  	if (location == 0 || location == GIT_SUBMODULE_STATUS_IN_WD) {
  		git_config_backend *mods;
  		const char *pattern = "submodule\\..*\\.path";
  		git_buf path = GIT_BUF_INIT;
  		fbp_data data = { NULL, NULL };
  
  		git_buf_puts(&path, name);
  		while (path.ptr[path.size-1] == '/') {
  			path.ptr[--path.size] = '\0';
  		}
  		data.path = path.ptr;
  
  		mods = open_gitmodules(repo, GITMODULES_EXISTING);
  
  		if (mods)
  			error = git_config_backend_foreach_match(mods, pattern, find_by_path, &data);
  
  		git_config_backend_free(mods);
  
  		if (error < 0) {
  			git_submodule_free(sm);
  			git_buf_dispose(&path);
  			return error;
  		}
  
  		if (data.name) {
  			git__free(sm->name);
  			sm->name = data.name;
  			sm->path = git_buf_detach(&path);
  
  			/* Try to load again with the right name */
  			if ((error = git_submodule_reload(sm, false)) < 0) {
  				git_submodule_free(sm);
  				return error;
  			}
  		}
  
  		git_buf_dispose(&path);
  	}
  
  	if ((error = git_submodule_location(&location, sm)) < 0) {
  		git_submodule_free(sm);
  		return error;
  	}
  
  	/* If we still haven't found it, do the WD check */
  	if (location == 0 || location == GIT_SUBMODULE_STATUS_IN_WD) {
  		git_submodule_free(sm);
  		error = GIT_ENOTFOUND;
  
  		/* If it's not configured, we still check if there's a repo at the path */
  		if (git_repository_workdir(repo)) {
  			git_buf path = GIT_BUF_INIT;
  			if (git_buf_join3(&path, '/',
  			                  git_repository_workdir(repo),
  					  name, DOT_GIT) < 0 ||
  			    git_path_validate_workdir_buf(NULL, &path) < 0)
  				return -1;
  
  			if (git_path_exists(path.ptr))
  				error = GIT_EEXISTS;
  
  			git_buf_dispose(&path);
  		}
  
  		submodule_set_lookup_error(error, name);
  		return error;
  	}
  
  	if (out)
  		*out = sm;
  	else
  		git_submodule_free(sm);
  
  	return 0;
  }
  
  int git_submodule_name_is_valid(git_repository *repo, const char *name, int flags)
  {
  	git_buf buf = GIT_BUF_INIT;
  	int error, isvalid;
  
  	if (flags == 0)
  		flags = GIT_PATH_REJECT_FILESYSTEM_DEFAULTS;
  
  	/* Avoid allocating a new string if we can avoid it */
  	if (strchr(name, '\\') != NULL) {
  		if ((error = git_path_normalize_slashes(&buf, name)) < 0)
  			return error;
  	} else {
  		git_buf_attach_notowned(&buf, name, strlen(name));
  	}
  
  	isvalid =  git_path_validate(repo, buf.ptr, 0, flags);
  	git_buf_dispose(&buf);
  
  	return isvalid;
  }
  
  static void submodule_free_dup(void *sm)
  {
  	git_submodule_free(sm);
  }
  
  static int submodule_get_or_create(git_submodule **out, git_repository *repo, git_strmap *map, const char *name)
  {
  	git_submodule *sm = NULL;
  	int error;
  
  	if ((sm = git_strmap_get(map, name)) != NULL)
  		goto done;
  
  	/* if the submodule doesn't exist yet in the map, create it */
  	if ((error = submodule_alloc(&sm, repo, name)) < 0)
  		return error;
  
  	if ((error = git_strmap_set(map, sm->name, sm)) < 0) {
  		git_submodule_free(sm);
  		return error;
  	}
  
  done:
  	GIT_REFCOUNT_INC(sm);
  	*out = sm;
  	return 0;
  }
  
  static int submodules_from_index(git_strmap *map, git_index *idx, git_config *cfg)
  {
  	int error;
  	git_iterator *i = NULL;
  	const git_index_entry *entry;
  	git_strmap *names;
  
  	if ((error = load_submodule_names(&names, git_index_owner(idx), cfg)))
  		goto done;
  
  	if ((error = git_iterator_for_index(&i, git_index_owner(idx), idx, NULL)) < 0)
  		goto done;
  
  	while (!(error = git_iterator_advance(&entry, i))) {
  		git_submodule *sm;
  
  		if ((sm = git_strmap_get(map, entry->path)) != NULL) {
  			if (S_ISGITLINK(entry->mode))
  				submodule_update_from_index_entry(sm, entry);
  			else
  				sm->flags |= GIT_SUBMODULE_STATUS__INDEX_NOT_SUBMODULE;
  		} else if (S_ISGITLINK(entry->mode)) {
  			const char *name;
  
  			if ((name = git_strmap_get(names, entry->path)) == NULL)
  				name = entry->path;
  
  			if (!submodule_get_or_create(&sm, git_index_owner(idx), map, name)) {
  				submodule_update_from_index_entry(sm, entry);
  				git_submodule_free(sm);
  			}
  		}
  	}
  
  	if (error == GIT_ITEROVER)
  		error = 0;
  
  done:
  	git_iterator_free(i);
  	free_submodule_names(names);
  
  	return error;
  }
  
  static int submodules_from_head(git_strmap *map, git_tree *head, git_config *cfg)
  {
  	int error;
  	git_iterator *i = NULL;
  	const git_index_entry *entry;
  	git_strmap *names;
  
  	if ((error = load_submodule_names(&names, git_tree_owner(head), cfg)))
  		goto done;
  
  	if ((error = git_iterator_for_tree(&i, head, NULL)) < 0)
  		goto done;
  
  	while (!(error = git_iterator_advance(&entry, i))) {
  		git_submodule *sm;
  
  		if ((sm = git_strmap_get(map, entry->path)) != NULL) {
  			if (S_ISGITLINK(entry->mode))
  				submodule_update_from_head_data(sm, entry->mode, &entry->id);
  			else
  				sm->flags |= GIT_SUBMODULE_STATUS__HEAD_NOT_SUBMODULE;
  		} else if (S_ISGITLINK(entry->mode)) {
  			const char *name;
  
  			if ((name = git_strmap_get(names, entry->path)) == NULL)
  				name = entry->path;
  
  			if (!submodule_get_or_create(&sm, git_tree_owner(head), map, name)) {
  				submodule_update_from_head_data(
  					sm, entry->mode, &entry->id);
  				git_submodule_free(sm);
  			}
  		}
  	}
  
  	if (error == GIT_ITEROVER)
  		error = 0;
  
  done:
  	git_iterator_free(i);
  	free_submodule_names(names);
  
  	return error;
  }
  
  /* If have_sm is true, sm is populated, otherwise map an repo are. */
  typedef struct {
  	git_config *mods;
  	git_strmap *map;
  	git_repository *repo;
  } lfc_data;
  
  int git_submodule__map(git_repository *repo, git_strmap *map)
  {
  	int error = 0;
  	git_index *idx = NULL;
  	git_tree *head = NULL;
  	git_buf path = GIT_BUF_INIT;
  	git_submodule *sm;
  	git_config *mods = NULL;
  	bool has_workdir;
  
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(map);
  
  	/* get sources that we will need to check */
  	if (git_repository_index(&idx, repo) < 0)
  		git_error_clear();
  	if (git_repository_head_tree(&head, repo) < 0)
  		git_error_clear();
  
  	has_workdir = git_repository_workdir(repo) != NULL;
  
  	if (has_workdir &&
  	    (error = git_repository_workdir_path(&path, repo, GIT_MODULES_FILE)) < 0)
  		goto cleanup;
  
  	/* add submodule information from .gitmodules */
  	if (has_workdir) {
  		lfc_data data = { 0 };
  		data.map = map;
  		data.repo = repo;
  
  		if ((error = gitmodules_snapshot(&mods, repo)) < 0) {
  			if (error == GIT_ENOTFOUND)
  				error = 0;
  			goto cleanup;
  		}
  
  		data.mods = mods;
  		if ((error = git_config_foreach(
  			    mods, submodule_load_each, &data)) < 0)
  			goto cleanup;
  	}
  	/* add back submodule information from index */
  	if (mods && idx) {
  		if ((error = submodules_from_index(map, idx, mods)) < 0)
  			goto cleanup;
  	}
  	/* add submodule information from HEAD */
  	if (mods && head) {
  		if ((error = submodules_from_head(map, head, mods)) < 0)
  			goto cleanup;
  	}
  	/* shallow scan submodules in work tree as needed */
  	if (has_workdir) {
  		git_strmap_foreach_value(map, sm, {
  				submodule_load_from_wd_lite(sm);
  			});
  	}
  
  cleanup:
  	git_config_free(mods);
  	/* TODO: if we got an error, mark submodule config as invalid? */
  	git_index_free(idx);
  	git_tree_free(head);
  	git_buf_dispose(&path);
  	return error;
  }
  
  int git_submodule_foreach(
  	git_repository *repo,
  	git_submodule_cb callback,
  	void *payload)
  {
  	git_vector snapshot = GIT_VECTOR_INIT;
  	git_strmap *submodules;
  	git_submodule *sm;
  	int error;
  	size_t i;
  
  	if (repo->is_bare) {
  		git_error_set(GIT_ERROR_SUBMODULE, "cannot get submodules without a working tree");
  		return -1;
  	}
  
  	if ((error = git_strmap_new(&submodules)) < 0)
  		return error;
  
  	if ((error = git_submodule__map(repo, submodules)) < 0)
  		goto done;
  
  	if (!(error = git_vector_init(
  			&snapshot, git_strmap_size(submodules), submodule_cmp))) {
  
  		git_strmap_foreach_value(submodules, sm, {
  			if ((error = git_vector_insert(&snapshot, sm)) < 0)
  				break;
  			GIT_REFCOUNT_INC(sm);
  		});
  	}
  
  	if (error < 0)
  		goto done;
  
  	git_vector_uniq(&snapshot, submodule_free_dup);
  
  	git_vector_foreach(&snapshot, i, sm) {
  		if ((error = callback(sm, sm->name, payload)) != 0) {
  			git_error_set_after_callback(error);
  			break;
  		}
  	}
  
  done:
  	git_vector_foreach(&snapshot, i, sm)
  		git_submodule_free(sm);
  	git_vector_free(&snapshot);
  
  	git_strmap_foreach_value(submodules, sm, {
  		git_submodule_free(sm);
  	});
  	git_strmap_free(submodules);
  
  	return error;
  }
  
  static int submodule_repo_init(
  	git_repository **out,
  	git_repository *parent_repo,
  	const char *path,
  	const char *url,
  	bool use_gitlink)
  {
  	int error = 0;
  	git_buf workdir = GIT_BUF_INIT, repodir = GIT_BUF_INIT;
  	git_repository_init_options initopt = GIT_REPOSITORY_INIT_OPTIONS_INIT;
  	git_repository *subrepo = NULL;
  
  	error = git_repository_workdir_path(&workdir, parent_repo, path);
  	if (error < 0)
  		goto cleanup;
  
  	initopt.flags = GIT_REPOSITORY_INIT_MKPATH | GIT_REPOSITORY_INIT_NO_REINIT;
  	initopt.origin_url = url;
  
  	/* init submodule repository and add origin remote as needed */
  
  	/* New style: sub-repo goes in <repo-dir>/modules/<name>/ with a
  	 * gitlink in the sub-repo workdir directory to that repository
  	 *
  	 * Old style: sub-repo goes directly into repo/<name>/.git/
  	 */
  	 if (use_gitlink) {
  		error = git_repository_item_path(&repodir, parent_repo, GIT_REPOSITORY_ITEM_MODULES);
  		if (error < 0)
  			goto cleanup;
  		error = git_buf_joinpath(&repodir, repodir.ptr, path);
  		if (error < 0)
  			goto cleanup;
  
  		initopt.workdir_path = workdir.ptr;
  		initopt.flags |=
  			GIT_REPOSITORY_INIT_NO_DOTGIT_DIR |
  			GIT_REPOSITORY_INIT_RELATIVE_GITLINK;
  
  		error = git_repository_init_ext(&subrepo, repodir.ptr, &initopt);
  	} else
  		error = git_repository_init_ext(&subrepo, workdir.ptr, &initopt);
  
  cleanup:
  	git_buf_dispose(&workdir);
  	git_buf_dispose(&repodir);
  
  	*out = subrepo;
  
  	return error;
  }
  
  int git_submodule_add_setup(
  	git_submodule **out,
  	git_repository *repo,
  	const char *url,
  	const char *path,
  	int use_gitlink)
  {
  	int error = 0;
  	git_config_backend *mods = NULL;
  	git_submodule *sm = NULL;
  	git_buf name = GIT_BUF_INIT, real_url = GIT_BUF_INIT;
  	git_repository *subrepo = NULL;
  	bool path_occupied;
  
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(url);
  	GIT_ASSERT_ARG(path);
  
  	/* see if there is already an entry for this submodule */
  
  	if (git_submodule_lookup(NULL, repo, path) < 0)
  		git_error_clear();
  	else {
  		git_error_set(GIT_ERROR_SUBMODULE,
  			"attempt to add submodule '%s' that already exists", path);
  		return GIT_EEXISTS;
  	}
  
  	/* validate and normalize path */
  
  	if (git__prefixcmp(path, git_repository_workdir(repo)) == 0)
  		path += strlen(git_repository_workdir(repo));
  
  	if (git_path_root(path) >= 0) {
  		git_error_set(GIT_ERROR_SUBMODULE, "submodule path must be a relative path");
  		error = -1;
  		goto cleanup;
  	}
  
  	if ((error = is_path_occupied(&path_occupied, repo, path)) < 0)
  		goto cleanup;
  
  	if (path_occupied) {
  		error = GIT_EEXISTS;
  		goto cleanup;
  	}
  
  	/* update .gitmodules */
  
  	if (!(mods = open_gitmodules(repo, GITMODULES_CREATE))) {
  		git_error_set(GIT_ERROR_SUBMODULE,
  			"adding submodules to a bare repository is not supported");
  		return -1;
  	}
  
  	if ((error = git_buf_printf(&name, "submodule.%s.path", path)) < 0 ||
  		(error = git_config_backend_set_string(mods, name.ptr, path)) < 0)
  		goto cleanup;
  
  	if ((error = submodule_config_key_trunc_puts(&name, "url")) < 0 ||
  		(error = git_config_backend_set_string(mods, name.ptr, url)) < 0)
  		goto cleanup;
  
  	git_buf_clear(&name);
  
  	/* init submodule repository and add origin remote as needed */
  
  	error = git_repository_workdir_path(&name, repo, path);
  	if (error < 0)
  		goto cleanup;
  
  	/* if the repo does not already exist, then init a new repo and add it.
  	 * Otherwise, just add the existing repo.
  	 */
  	if (!(git_path_exists(name.ptr) &&
  		git_path_contains(&name, DOT_GIT))) {
  
  		/* resolve the actual URL to use */
  		if ((error = git_submodule_resolve_url(&real_url, repo, url)) < 0)
  			goto cleanup;
  
  		 if ((error = submodule_repo_init(&subrepo, repo, path, real_url.ptr, use_gitlink)) < 0)
  			goto cleanup;
  	}
  
  	if ((error = git_submodule_lookup(&sm, repo, path)) < 0)
  		goto cleanup;
  
  	error = git_submodule_init(sm, false);
  
  cleanup:
  	if (error && sm) {
  		git_submodule_free(sm);
  		sm = NULL;
  	}
  	if (out != NULL)
  		*out = sm;
  
  	git_config_backend_free(mods);
  	git_repository_free(subrepo);
  	git_buf_dispose(&real_url);
  	git_buf_dispose(&name);
  
  	return error;
  }
  
  int git_submodule_repo_init(
  	git_repository **out,
  	const git_submodule *sm,
  	int use_gitlink)
  {
  	int error;
  	git_repository *sub_repo = NULL;
  	const char *configured_url;
  	git_config *cfg = NULL;
  	git_buf buf = GIT_BUF_INIT;
  
  	GIT_ASSERT_ARG(out);
  	GIT_ASSERT_ARG(sm);
  
  	/* get the configured remote url of the submodule */
  	if ((error = git_buf_printf(&buf, "submodule.%s.url", sm->name)) < 0 ||
  		(error = git_repository_config_snapshot(&cfg, sm->repo)) < 0 ||
  		(error = git_config_get_string(&configured_url, cfg, buf.ptr)) < 0 ||
  		(error = submodule_repo_init(&sub_repo, sm->repo, sm->path, configured_url, use_gitlink)) < 0)
  		goto done;
  
  	*out = sub_repo;
  
  done:
  	git_config_free(cfg);
  	git_buf_dispose(&buf);
  	return error;
  }
  
  static int clone_return_origin(git_remote **out, git_repository *repo, const char *name, const char *url, void *payload)
  {
  	GIT_UNUSED(url);
  	GIT_UNUSED(payload);
  	return git_remote_lookup(out, repo, name);
  }
  
  static int clone_return_repo(git_repository **out, const char *path, int bare, void *payload)
  {
  	git_submodule *sm = payload;
  
  	GIT_UNUSED(path);
  	GIT_UNUSED(bare);
  	return git_submodule_open(out, sm);
  }
  
  int git_submodule_clone(git_repository **out, git_submodule *submodule, const git_submodule_update_options *given_opts)
  {
  	int error;
  	git_repository *clone;
  	git_buf rel_path = GIT_BUF_INIT;
  	git_submodule_update_options sub_opts = GIT_SUBMODULE_UPDATE_OPTIONS_INIT;
  	git_clone_options opts = GIT_CLONE_OPTIONS_INIT;
  
  	GIT_ASSERT_ARG(submodule);
  
  	if (given_opts)
  		memcpy(&sub_opts, given_opts, sizeof(sub_opts));
  
  	GIT_ERROR_CHECK_VERSION(&sub_opts, GIT_SUBMODULE_UPDATE_OPTIONS_VERSION, "git_submodule_update_options");
  
  	memcpy(&opts.checkout_opts, &sub_opts.checkout_opts, sizeof(sub_opts.checkout_opts));
  	memcpy(&opts.fetch_opts, &sub_opts.fetch_opts, sizeof(sub_opts.fetch_opts));
  	opts.repository_cb = clone_return_repo;
  	opts.repository_cb_payload = submodule;
  	opts.remote_cb = clone_return_origin;
  	opts.remote_cb_payload = submodule;
  
  	error = git_repository_workdir_path(&rel_path, git_submodule_owner(submodule), git_submodule_path(submodule));
  	if (error < 0)
  		goto cleanup;
  
  	error = git_clone__submodule(&clone, git_submodule_url(submodule), git_buf_cstr(&rel_path), &opts);
  	if (error < 0)
  		goto cleanup;
  
  	if (!out)
  		git_repository_free(clone);
  	else
  		*out = clone;
  
  cleanup:
  	git_buf_dispose(&rel_path);
  
  	return error;
  }
  
  int git_submodule_add_finalize(git_submodule *sm)
  {
  	int error;
  	git_index *index;
  
  	GIT_ASSERT_ARG(sm);
  
  	if ((error = git_repository_index__weakptr(&index, sm->repo)) < 0 ||
  		(error = git_index_add_bypath(index, GIT_MODULES_FILE)) < 0)
  		return error;
  
  	return git_submodule_add_to_index(sm, true);
  }
  
  int git_submodule_add_to_index(git_submodule *sm, int write_index)
  {
  	int error;
  	git_repository *sm_repo = NULL;
  	git_index *index;
  	git_buf path = GIT_BUF_INIT;
  	git_commit *head;
  	git_index_entry entry;
  	struct stat st;
  
  	GIT_ASSERT_ARG(sm);
  
  	/* force reload of wd OID by git_submodule_open */
  	sm->flags = sm->flags & ~GIT_SUBMODULE_STATUS__WD_OID_VALID;
  
  	if ((error = git_repository_index__weakptr(&index, sm->repo)) < 0 ||
  	    (error = git_repository_workdir_path(&path, sm->repo, sm->path)) < 0 ||
  	    (error = git_submodule_open(&sm_repo, sm)) < 0)
  		goto cleanup;
  
  	/* read stat information for submodule working directory */
  	if (p_stat(path.ptr, &st) < 0) {
  		git_error_set(GIT_ERROR_SUBMODULE,
  			"cannot add submodule without working directory");
  		error = -1;
  		goto cleanup;
  	}
  
  	memset(&entry, 0, sizeof(entry));
  	entry.path = sm->path;
  	git_index_entry__init_from_stat(
  		&entry, &st, !(git_index_caps(index) & GIT_INDEX_CAPABILITY_NO_FILEMODE));
  
  	/* calling git_submodule_open will have set sm->wd_oid if possible */
  	if ((sm->flags & GIT_SUBMODULE_STATUS__WD_OID_VALID) == 0) {
  		git_error_set(GIT_ERROR_SUBMODULE,
  			"cannot add submodule without HEAD to index");
  		error = -1;
  		goto cleanup;
  	}
  	git_oid_cpy(&entry.id, &sm->wd_oid);
  
  	if ((error = git_commit_lookup(&head, sm_repo, &sm->wd_oid)) < 0)
  		goto cleanup;
  
  	entry.ctime.seconds = (int32_t)git_commit_time(head);
  	entry.ctime.nanoseconds = 0;
  	entry.mtime.seconds = (int32_t)git_commit_time(head);
  	entry.mtime.nanoseconds = 0;
  
  	git_commit_free(head);
  
  	/* add it */
  	error = git_index_add(index, &entry);
  
  	/* write it, if requested */
  	if (!error && write_index) {
  		error = git_index_write(index);
  
  		if (!error)
  			git_oid_cpy(&sm->index_oid, &sm->wd_oid);
  	}
  
  cleanup:
  	git_repository_free(sm_repo);
  	git_buf_dispose(&path);
  	return error;
  }
  
  static const char *submodule_update_to_str(git_submodule_update_t update)
  {
  	int i;
  	for (i = 0; i < (int)ARRAY_SIZE(_sm_update_map); ++i)
  		if (_sm_update_map[i].map_value == (int)update)
  			return _sm_update_map[i].str_match;
  	return NULL;
  }
  
  git_repository *git_submodule_owner(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  	return submodule->repo;
  }
  
  const char *git_submodule_name(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  	return submodule->name;
  }
  
  const char *git_submodule_path(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  	return submodule->path;
  }
  
  const char *git_submodule_url(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  	return submodule->url;
  }
  
  int git_submodule_resolve_url(git_buf *out, git_repository *repo, const char *url)
  {
  	int error = 0;
  	git_buf normalized = GIT_BUF_INIT;
  
  	GIT_ASSERT_ARG(out);
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(url);
  
  	if ((error = git_buf_sanitize(out)) < 0)
  		return error;
  
  	/* We do this in all platforms in case someone on Windows created the .gitmodules */
  	if (strchr(url, '\\')) {
  		if ((error = git_path_normalize_slashes(&normalized, url)) < 0)
  			return error;
  
  		url = normalized.ptr;
  	}
  
  
  	if (git_path_is_relative(url)) {
  		if (!(error = get_url_base(out, repo)))
  			error = git_path_apply_relative(out, url);
  	} else if (strchr(url, ':') != NULL || url[0] == '/') {
  		error = git_buf_sets(out, url);
  	} else {
  		git_error_set(GIT_ERROR_SUBMODULE, "invalid format for submodule URL");
  		error = -1;
  	}
  
  	git_buf_dispose(&normalized);
  	return error;
  }
  
  static int write_var(git_repository *repo, const char *name, const char *var, const char *val)
  {
  	git_buf key = GIT_BUF_INIT;
  	git_config_backend *mods;
  	int error;
  
  	mods = open_gitmodules(repo, GITMODULES_CREATE);
  	if (!mods)
  		return -1;
  
  	if ((error = git_buf_printf(&key, "submodule.%s.%s", name, var)) < 0)
  		goto cleanup;
  
  	if (val)
  		error = git_config_backend_set_string(mods, key.ptr, val);
  	else
  		error = git_config_backend_delete(mods, key.ptr);
  
  	git_buf_dispose(&key);
  
  cleanup:
  	git_config_backend_free(mods);
  	return error;
  }
  
  static int write_mapped_var(git_repository *repo, const char *name, git_configmap *maps, size_t nmaps, const char *var, int ival)
  {
  	git_configmap_t type;
  	const char *val;
  
  	if (git_config_lookup_map_enum(&type, &val, maps, nmaps, ival) < 0) {
  		git_error_set(GIT_ERROR_SUBMODULE, "invalid value for %s", var);
  		return -1;
  	}
  
  	if (type == GIT_CONFIGMAP_TRUE)
  		val = "true";
  
  	return write_var(repo, name, var, val);
  }
  
  const char *git_submodule_branch(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  	return submodule->branch;
  }
  
  int git_submodule_set_branch(git_repository *repo, const char *name, const char *branch)
  {
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(name);
  
  	return write_var(repo, name, "branch", branch);
  }
  
  int git_submodule_set_url(git_repository *repo, const char *name, const char *url)
  {
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(name);
  	GIT_ASSERT_ARG(url);
  
  	return write_var(repo, name, "url", url);
  }
  
  const git_oid *git_submodule_index_id(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  
  	if (submodule->flags & GIT_SUBMODULE_STATUS__INDEX_OID_VALID)
  		return &submodule->index_oid;
  	else
  		return NULL;
  }
  
  const git_oid *git_submodule_head_id(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  
  	if (submodule->flags & GIT_SUBMODULE_STATUS__HEAD_OID_VALID)
  		return &submodule->head_oid;
  	else
  		return NULL;
  }
  
  const git_oid *git_submodule_wd_id(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, NULL);
  
  	/* load unless we think we have a valid oid */
  	if (!(submodule->flags & GIT_SUBMODULE_STATUS__WD_OID_VALID)) {
  		git_repository *subrepo;
  
  		/* calling submodule open grabs the HEAD OID if possible */
  		if (!git_submodule_open_bare(&subrepo, submodule))
  			git_repository_free(subrepo);
  		else
  			git_error_clear();
  	}
  
  	if (submodule->flags & GIT_SUBMODULE_STATUS__WD_OID_VALID)
  		return &submodule->wd_oid;
  	else
  		return NULL;
  }
  
  git_submodule_ignore_t git_submodule_ignore(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, GIT_SUBMODULE_IGNORE_UNSPECIFIED);
  
  	return (submodule->ignore < GIT_SUBMODULE_IGNORE_NONE) ?
  		GIT_SUBMODULE_IGNORE_NONE : submodule->ignore;
  }
  
  int git_submodule_set_ignore(git_repository *repo, const char *name, git_submodule_ignore_t ignore)
  {
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(name);
  
  	return write_mapped_var(repo, name, _sm_ignore_map, ARRAY_SIZE(_sm_ignore_map), "ignore", ignore);
  }
  
  git_submodule_update_t git_submodule_update_strategy(git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, GIT_SUBMODULE_UPDATE_NONE);
  
  	return (submodule->update < GIT_SUBMODULE_UPDATE_CHECKOUT) ?
  		GIT_SUBMODULE_UPDATE_CHECKOUT : submodule->update;
  }
  
  int git_submodule_set_update(git_repository *repo, const char *name, git_submodule_update_t update)
  {
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(name);
  
  	return write_mapped_var(repo, name, _sm_update_map, ARRAY_SIZE(_sm_update_map), "update", update);
  }
  
  git_submodule_recurse_t git_submodule_fetch_recurse_submodules(
  	git_submodule *submodule)
  {
  	GIT_ASSERT_ARG_WITH_RETVAL(submodule, GIT_SUBMODULE_RECURSE_NO);
  	return submodule->fetch_recurse;
  }
  
  int git_submodule_set_fetch_recurse_submodules(git_repository *repo, const char *name, git_submodule_recurse_t recurse)
  {
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(name);
  
  	return write_mapped_var(repo, name, _sm_recurse_map, ARRAY_SIZE(_sm_recurse_map), "fetchRecurseSubmodules", recurse);
  }
  
  static int submodule_repo_create(
  	git_repository **out,
  	git_repository *parent_repo,
  	const char *path)
  {
  	int error = 0;
  	git_buf workdir = GIT_BUF_INIT, repodir = GIT_BUF_INIT;
  	git_repository_init_options initopt = GIT_REPOSITORY_INIT_OPTIONS_INIT;
  	git_repository *subrepo = NULL;
  
  	initopt.flags =
  		GIT_REPOSITORY_INIT_MKPATH |
  		GIT_REPOSITORY_INIT_NO_REINIT |
  		GIT_REPOSITORY_INIT_NO_DOTGIT_DIR |
  		GIT_REPOSITORY_INIT_RELATIVE_GITLINK;
  
  	/* Workdir: path to sub-repo working directory */
  	error = git_repository_workdir_path(&workdir, parent_repo, path);
  	if (error < 0)
  		goto cleanup;
  
  	initopt.workdir_path = workdir.ptr;
  
  	/**
  	 * Repodir: path to the sub-repo. sub-repo goes in:
  	 * <repo-dir>/modules/<name>/ with a gitlink in the
  	 * sub-repo workdir directory to that repository.
  	 */
  	error = git_repository_item_path(&repodir, parent_repo, GIT_REPOSITORY_ITEM_MODULES);
  	if (error < 0)
  		goto cleanup;
  	error = git_buf_joinpath(&repodir, repodir.ptr, path);
  	if (error < 0)
  		goto cleanup;
  
  	error = git_repository_init_ext(&subrepo, repodir.ptr, &initopt);
  
  cleanup:
  	git_buf_dispose(&workdir);
  	git_buf_dispose(&repodir);
  
  	*out = subrepo;
  
  	return error;
  }
  
  /**
   * Callback to override sub-repository creation when
   * cloning a sub-repository.
   */
  static int git_submodule_update_repo_init_cb(
  	git_repository **out,
  	const char *path,
  	int bare,
  	void *payload)
  {
  	git_submodule *sm;
  
  	GIT_UNUSED(bare);
  
  	sm = payload;
  
  	return submodule_repo_create(out, sm->repo, path);
  }
  
  int git_submodule_update_options_init(git_submodule_update_options *opts, unsigned int version)
  {
  	GIT_INIT_STRUCTURE_FROM_TEMPLATE(
  		opts, version, git_submodule_update_options, GIT_SUBMODULE_UPDATE_OPTIONS_INIT);
  	return 0;
  }
  
  #ifndef GIT_DEPRECATE_HARD
  int git_submodule_update_init_options(git_submodule_update_options *opts, unsigned int version)
  {
  	return git_submodule_update_options_init(opts, version);
  }
  #endif
  
  int git_submodule_update(git_submodule *sm, int init, git_submodule_update_options *_update_options)
  {
  	int error;
  	unsigned int submodule_status;
  	git_config *config = NULL;
  	const char *submodule_url;
  	git_repository *sub_repo = NULL;
  	git_remote *remote = NULL;
  	git_object *target_commit = NULL;
  	git_buf buf = GIT_BUF_INIT;
  	git_submodule_update_options update_options = GIT_SUBMODULE_UPDATE_OPTIONS_INIT;
  	git_clone_options clone_options = GIT_CLONE_OPTIONS_INIT;
  
  	GIT_ASSERT_ARG(sm);
  
  	if (_update_options)
  		memcpy(&update_options, _update_options, sizeof(git_submodule_update_options));
  
  	GIT_ERROR_CHECK_VERSION(&update_options, GIT_SUBMODULE_UPDATE_OPTIONS_VERSION, "git_submodule_update_options");
  
  	/* Copy over the remote callbacks */
  	memcpy(&clone_options.fetch_opts, &update_options.fetch_opts, sizeof(git_fetch_options));
  
  	/* Get the status of the submodule to determine if it is already initialized  */
  	if ((error = git_submodule_status(&submodule_status, sm->repo, sm->name, GIT_SUBMODULE_IGNORE_UNSPECIFIED)) < 0)
  		goto done;
  
  	/*
  	 * If submodule work dir is not already initialized, check to see
  	 * what we need to do (initialize, clone, return error...)
  	 */
  	if (submodule_status & GIT_SUBMODULE_STATUS_WD_UNINITIALIZED) {
  		/*
  		 * Work dir is not initialized, check to see if the submodule
  		 * info has been copied into .git/config
  		 */
  		if ((error = git_repository_config_snapshot(&config, sm->repo)) < 0 ||
  			(error = git_buf_printf(&buf, "submodule.%s.url", git_submodule_name(sm))) < 0)
  			goto done;
  
  		if ((error = git_config_get_string(&submodule_url, config, git_buf_cstr(&buf))) < 0) {
  			/*
  			 * If the error is not "not found" or if it is "not found" and we are not
  			 * initializing the submodule, then return error.
  			 */
  			if (error != GIT_ENOTFOUND)
  				goto done;
  
  			if (!init) {
  				git_error_set(GIT_ERROR_SUBMODULE, "submodule is not initialized");
  				error = GIT_ERROR;
  				goto done;
  			}
  
  			/* The submodule has not been initialized yet - initialize it now.*/
  			if ((error = git_submodule_init(sm, 0)) < 0)
  				goto done;
  
  			git_config_free(config);
  			config = NULL;
  
  			if ((error = git_repository_config_snapshot(&config, sm->repo)) < 0 ||
  				(error = git_config_get_string(&submodule_url, config, git_buf_cstr(&buf))) < 0)
  				goto done;
  		}
  
  		/** submodule is initialized - now clone it **/
  		/* override repo creation */
  		clone_options.repository_cb = git_submodule_update_repo_init_cb;
  		clone_options.repository_cb_payload = sm;
  
  		/*
  		 * Do not perform checkout as part of clone, instead we
  		 * will checkout the specific commit manually.
  		 */
  		clone_options.checkout_opts.checkout_strategy = GIT_CHECKOUT_NONE;
  
  		if ((error = git_clone(&sub_repo, submodule_url, sm->path, &clone_options)) < 0 ||
  			(error = git_repository_set_head_detached(sub_repo, git_submodule_index_id(sm))) < 0 ||
  			(error = git_checkout_head(sub_repo, &update_options.checkout_opts)) != 0)
  			goto done;
  	} else {
  		const git_oid *oid;
  
  		/**
  		 * Work dir is initialized - look up the commit in the parent repository's index,
  		 * update the workdir contents of the subrepository, and set the subrepository's
  		 * head to the new commit.
  		 */
  		if ((error = git_submodule_open(&sub_repo, sm)) < 0)
  			goto done;
  
  		if ((oid = git_submodule_index_id(sm)) == NULL) {
  			git_error_set(GIT_ERROR_SUBMODULE, "could not get ID of submodule in index");
  			error = -1;
  			goto done;
  		}
  
  		/* Look up the target commit in the submodule. */
  		if ((error = git_object_lookup(&target_commit, sub_repo, oid, GIT_OBJECT_COMMIT)) < 0) {
  			/* If it isn't found then fetch and try again. */
  			if (error != GIT_ENOTFOUND || !update_options.allow_fetch ||
  				(error = lookup_default_remote(&remote, sub_repo)) < 0 ||
  				(error = git_remote_fetch(remote, NULL, &update_options.fetch_opts, NULL)) < 0 ||
  				(error = git_object_lookup(&target_commit, sub_repo, git_submodule_index_id(sm), GIT_OBJECT_COMMIT)) < 0)
  				goto done;
  		}
  
  		if ((error = git_checkout_tree(sub_repo, target_commit, &update_options.checkout_opts)) != 0 ||
  			(error = git_repository_set_head_detached(sub_repo, git_submodule_index_id(sm))) < 0)
  			goto done;
  
  		/* Invalidate the wd flags as the workdir has been updated. */
  		sm->flags = sm->flags &
  			~(GIT_SUBMODULE_STATUS_IN_WD |
  		  	GIT_SUBMODULE_STATUS__WD_OID_VALID |
  		  	GIT_SUBMODULE_STATUS__WD_SCANNED);
  	}
  
  done:
  	git_buf_dispose(&buf);
  	git_config_free(config);
  	git_object_free(target_commit);
  	git_remote_free(remote);
  	git_repository_free(sub_repo);
  
  	return error;
  }
  
  int git_submodule_init(git_submodule *sm, int overwrite)
  {
  	int error;
  	const char *val;
  	git_buf key = GIT_BUF_INIT, effective_submodule_url = GIT_BUF_INIT;
  	git_config *cfg = NULL;
  
  	if (!sm->url) {
  		git_error_set(GIT_ERROR_SUBMODULE,
  			"no URL configured for submodule '%s'", sm->name);
  		return -1;
  	}
  
  	if ((error = git_repository_config(&cfg, sm->repo)) < 0)
  		return error;
  
  	/* write "submodule.NAME.url" */
  
  	if ((error = git_submodule_resolve_url(&effective_submodule_url, sm->repo, sm->url)) < 0 ||
  		(error = git_buf_printf(&key, "submodule.%s.url", sm->name)) < 0 ||
  		(error = git_config__update_entry(
  			cfg, key.ptr, effective_submodule_url.ptr, overwrite != 0, false)) < 0)
  		goto cleanup;
  
  	/* write "submodule.NAME.update" if not default */
  
  	val = (sm->update == GIT_SUBMODULE_UPDATE_CHECKOUT) ?
  		NULL : submodule_update_to_str(sm->update);
  
  	if ((error = git_buf_printf(&key, "submodule.%s.update", sm->name)) < 0 ||
  		(error = git_config__update_entry(
  			cfg, key.ptr, val, overwrite != 0, false)) < 0)
  		goto cleanup;
  
  	/* success */
  
  cleanup:
  	git_config_free(cfg);
  	git_buf_dispose(&key);
  	git_buf_dispose(&effective_submodule_url);
  
  	return error;
  }
  
  int git_submodule_sync(git_submodule *sm)
  {
  	git_buf key = GIT_BUF_INIT, url = GIT_BUF_INIT, remote_name = GIT_BUF_INIT;
  	git_repository *smrepo = NULL;
  	git_config *cfg = NULL;
  	int error = 0;
  
  	if (!sm->url) {
  		git_error_set(GIT_ERROR_SUBMODULE, "no URL configured for submodule '%s'", sm->name);
  		return -1;
  	}
  
  	/* copy URL over to config only if it already exists */
  	if ((error = git_repository_config__weakptr(&cfg, sm->repo)) < 0 ||
  	    (error = git_buf_printf(&key, "submodule.%s.url", sm->name)) < 0 ||
  	    (error = git_submodule_resolve_url(&url, sm->repo, sm->url)) < 0 ||
  	    (error = git_config__update_entry(cfg, key.ptr, url.ptr, true, true)) < 0)
  		goto out;
  
  	if (!(sm->flags & GIT_SUBMODULE_STATUS_IN_WD))
  		goto out;
  
  	/* if submodule exists in the working directory, update remote url */
  	if ((error = git_submodule_open(&smrepo, sm)) < 0 ||
  	    (error = git_repository_config__weakptr(&cfg, smrepo)) < 0)
  		goto out;
  
  	if (lookup_head_remote_key(&remote_name, smrepo) == 0) {
  		if ((error = git_buf_join3(&key, '.', "remote", remote_name.ptr, "url")) < 0)
  			goto out;
  	} else if ((error = git_buf_sets(&key, "remote.origin.url")) < 0) {
  		goto out;
  	}
  
  	if ((error = git_config__update_entry(cfg, key.ptr, url.ptr, true, false)) < 0)
  		goto out;
  
  out:
  	git_repository_free(smrepo);
  	git_buf_dispose(&remote_name);
  	git_buf_dispose(&key);
  	git_buf_dispose(&url);
  	return error;
  }
  
  static int git_submodule__open(
  	git_repository **subrepo, git_submodule *sm, bool bare)
  {
  	int error;
  	git_buf path = GIT_BUF_INIT;
  	unsigned int flags = GIT_REPOSITORY_OPEN_NO_SEARCH;
  	const char *wd;
  
  	GIT_ASSERT_ARG(sm);
  	GIT_ASSERT_ARG(subrepo);
  
  	if (git_repository__ensure_not_bare(
  			sm->repo, "open submodule repository") < 0)
  		return GIT_EBAREREPO;
  
  	wd = git_repository_workdir(sm->repo);
  
  	if (git_buf_join3(&path, '/', wd, sm->path, DOT_GIT) < 0)
  		return -1;
  
  	sm->flags = sm->flags &
  		~(GIT_SUBMODULE_STATUS_IN_WD |
  		  GIT_SUBMODULE_STATUS__WD_OID_VALID |
  		  GIT_SUBMODULE_STATUS__WD_SCANNED);
  
  	if (bare)
  		flags |= GIT_REPOSITORY_OPEN_BARE;
  
  	error = git_repository_open_ext(subrepo, path.ptr, flags, wd);
  
  	/* if we opened the submodule successfully, grab HEAD OID, etc. */
  	if (!error) {
  		sm->flags |= GIT_SUBMODULE_STATUS_IN_WD |
  			GIT_SUBMODULE_STATUS__WD_SCANNED;
  
  		if (!git_reference_name_to_id(&sm->wd_oid, *subrepo, GIT_HEAD_FILE))
  			sm->flags |= GIT_SUBMODULE_STATUS__WD_OID_VALID;
  		else
  			git_error_clear();
  	} else if (git_path_exists(path.ptr)) {
  		sm->flags |= GIT_SUBMODULE_STATUS__WD_SCANNED |
  			GIT_SUBMODULE_STATUS_IN_WD;
  	} else {
  		git_buf_rtruncate_at_char(&path, '/'); /* remove "/.git" */
  
  		if (git_path_isdir(path.ptr))
  			sm->flags |= GIT_SUBMODULE_STATUS__WD_SCANNED;
  	}
  
  	git_buf_dispose(&path);
  
  	return error;
  }
  
  int git_submodule_open_bare(git_repository **subrepo, git_submodule *sm)
  {
  	return git_submodule__open(subrepo, sm, true);
  }
  
  int git_submodule_open(git_repository **subrepo, git_submodule *sm)
  {
  	return git_submodule__open(subrepo, sm, false);
  }
  
  static void submodule_update_from_index_entry(
  	git_submodule *sm, const git_index_entry *ie)
  {
  	bool already_found = (sm->flags & GIT_SUBMODULE_STATUS_IN_INDEX) != 0;
  
  	if (!S_ISGITLINK(ie->mode)) {
  		if (!already_found)
  			sm->flags |= GIT_SUBMODULE_STATUS__INDEX_NOT_SUBMODULE;
  	} else {
  		if (already_found)
  			sm->flags |= GIT_SUBMODULE_STATUS__INDEX_MULTIPLE_ENTRIES;
  		else
  			git_oid_cpy(&sm->index_oid, &ie->id);
  
  		sm->flags |= GIT_SUBMODULE_STATUS_IN_INDEX |
  			GIT_SUBMODULE_STATUS__INDEX_OID_VALID;
  	}
  }
  
  static int submodule_update_index(git_submodule *sm)
  {
  	git_index *index;
  	const git_index_entry *ie;
  
  	if (git_repository_index__weakptr(&index, sm->repo) < 0)
  		return -1;
  
  	sm->flags = sm->flags &
  		~(GIT_SUBMODULE_STATUS_IN_INDEX |
  		  GIT_SUBMODULE_STATUS__INDEX_OID_VALID);
  
  	if (!(ie = git_index_get_bypath(index, sm->path, 0)))
  		return 0;
  
  	submodule_update_from_index_entry(sm, ie);
  
  	return 0;
  }
  
  static void submodule_update_from_head_data(
  	git_submodule *sm, mode_t mode, const git_oid *id)
  {
  	if (!S_ISGITLINK(mode))
  		sm->flags |= GIT_SUBMODULE_STATUS__HEAD_NOT_SUBMODULE;
  	else {
  		git_oid_cpy(&sm->head_oid, id);
  
  		sm->flags |= GIT_SUBMODULE_STATUS_IN_HEAD |
  			GIT_SUBMODULE_STATUS__HEAD_OID_VALID;
  	}
  }
  
  static int submodule_update_head(git_submodule *submodule)
  {
  	git_tree *head = NULL;
  	git_tree_entry *te = NULL;
  
  	submodule->flags = submodule->flags &
  		~(GIT_SUBMODULE_STATUS_IN_HEAD |
  		  GIT_SUBMODULE_STATUS__HEAD_OID_VALID);
  
  	/* if we can't look up file in current head, then done */
  	if (git_repository_head_tree(&head, submodule->repo) < 0 ||
  		git_tree_entry_bypath(&te, head, submodule->path) < 0)
  		git_error_clear();
  	else
  		submodule_update_from_head_data(submodule, te->attr, git_tree_entry_id(te));
  
  	git_tree_entry_free(te);
  	git_tree_free(head);
  	return 0;
  }
  
  int git_submodule_reload(git_submodule *sm, int force)
  {
  	git_config *mods = NULL;
  	int error;
  
  	GIT_UNUSED(force);
  
  	GIT_ASSERT_ARG(sm);
  
  	if ((error = git_submodule_name_is_valid(sm->repo, sm->name, 0)) <= 0)
  		/* This should come with a warning, but we've no API for that */
  		goto out;
  
  	if (git_repository_is_bare(sm->repo))
  		goto out;
  
  	/* refresh config data */
  	if ((error = gitmodules_snapshot(&mods, sm->repo)) < 0 && error != GIT_ENOTFOUND)
  		goto out;
  
  	if (mods != NULL && (error = submodule_read_config(sm, mods)) < 0)
  		goto out;
  
  	/* refresh wd data */
  	sm->flags &=
  		~(GIT_SUBMODULE_STATUS_IN_WD |
  		  GIT_SUBMODULE_STATUS__WD_OID_VALID |
  		  GIT_SUBMODULE_STATUS__WD_FLAGS);
  
  	if ((error = submodule_load_from_wd_lite(sm)) < 0 ||
  	    (error = submodule_update_index(sm)) < 0 ||
  	    (error = submodule_update_head(sm)) < 0)
  		goto out;
  
  out:
  	git_config_free(mods);
  	return error;
  }
  
  static void submodule_copy_oid_maybe(
  	git_oid *tgt, const git_oid *src, bool valid)
  {
  	if (tgt) {
  		if (valid)
  			memcpy(tgt, src, sizeof(*tgt));
  		else
  			memset(tgt, 0, sizeof(*tgt));
  	}
  }
  
  int git_submodule__status(
  	unsigned int *out_status,
  	git_oid *out_head_id,
  	git_oid *out_index_id,
  	git_oid *out_wd_id,
  	git_submodule *sm,
  	git_submodule_ignore_t ign)
  {
  	unsigned int status;
  	git_repository *smrepo = NULL;
  
  	if (ign == GIT_SUBMODULE_IGNORE_UNSPECIFIED)
  		ign = sm->ignore;
  
  	/* only return location info if ignore == all */
  	if (ign == GIT_SUBMODULE_IGNORE_ALL) {
  		*out_status = (sm->flags & GIT_SUBMODULE_STATUS__IN_FLAGS);
  		return 0;
  	}
  
  	/* If the user has requested caching submodule state, performing these
  	 * expensive operations (especially `submodule_update_head`, which is
  	 * bottlenecked on `git_repository_head_tree`) eliminates much of the
  	 * advantage.  We will, therefore, interpret the request for caching to
  	 * apply here to and skip them.
  	 */
  
  	if (sm->repo->submodule_cache == NULL) {
  		/* refresh the index OID */
  		if (submodule_update_index(sm) < 0)
  			return -1;
  
  		/* refresh the HEAD OID */
  		if (submodule_update_head(sm) < 0)
  			return -1;
  	}
  
  	/* for ignore == dirty, don't scan the working directory */
  	if (ign == GIT_SUBMODULE_IGNORE_DIRTY) {
  		/* git_submodule_open_bare will load WD OID data */
  		if (git_submodule_open_bare(&smrepo, sm) < 0)
  			git_error_clear();
  		else
  			git_repository_free(smrepo);
  		smrepo = NULL;
  	} else if (git_submodule_open(&smrepo, sm) < 0) {
  		git_error_clear();
  		smrepo = NULL;
  	}
  
  	status = GIT_SUBMODULE_STATUS__CLEAR_INTERNAL(sm->flags);
  
  	submodule_get_index_status(&status, sm);
  	submodule_get_wd_status(&status, sm, smrepo, ign);
  
  	git_repository_free(smrepo);
  
  	*out_status = status;
  
  	submodule_copy_oid_maybe(out_head_id, &sm->head_oid,
  		(sm->flags & GIT_SUBMODULE_STATUS__HEAD_OID_VALID) != 0);
  	submodule_copy_oid_maybe(out_index_id, &sm->index_oid,
  		(sm->flags & GIT_SUBMODULE_STATUS__INDEX_OID_VALID) != 0);
  	submodule_copy_oid_maybe(out_wd_id, &sm->wd_oid,
  		(sm->flags & GIT_SUBMODULE_STATUS__WD_OID_VALID) != 0);
  
  	return 0;
  }
  
  int git_submodule_status(unsigned int *status, git_repository *repo, const char *name, git_submodule_ignore_t ignore)
  {
  	git_submodule *sm;
  	int error;
  
  	GIT_ASSERT_ARG(status);
  	GIT_ASSERT_ARG(repo);
  	GIT_ASSERT_ARG(name);
  
  	if ((error = git_submodule_lookup(&sm, repo, name)) < 0)
  		return error;
  
  	error = git_submodule__status(status, NULL, NULL, NULL, sm, ignore);
  	git_submodule_free(sm);
  
  	return error;
  }
  
  int git_submodule_location(unsigned int *location, git_submodule *sm)
  {
  	GIT_ASSERT_ARG(location);
  	GIT_ASSERT_ARG(sm);
  
  	return git_submodule__status(
  		location, NULL, NULL, NULL, sm, GIT_SUBMODULE_IGNORE_ALL);
  }
  
  /*
   * INTERNAL FUNCTIONS
   */
  
  static int submodule_alloc(
  	git_submodule **out, git_repository *repo, const char *name)
  {
  	size_t namelen;
  	git_submodule *sm;
  
  	if (!name || !(namelen = strlen(name))) {
  		git_error_set(GIT_ERROR_SUBMODULE, "invalid submodule name");
  		return -1;
  	}
  
  	sm = git__calloc(1, sizeof(git_submodule));
  	GIT_ERROR_CHECK_ALLOC(sm);
  
  	sm->name = sm->path = git__strdup(name);
  	if (!sm->name) {
  		git__free(sm);
  		return -1;
  	}
  
  	GIT_REFCOUNT_INC(sm);
  	sm->ignore = sm->ignore_default = GIT_SUBMODULE_IGNORE_NONE;
  	sm->update = sm->update_default = GIT_SUBMODULE_UPDATE_CHECKOUT;
  	sm->fetch_recurse = sm->fetch_recurse_default = GIT_SUBMODULE_RECURSE_NO;
  	sm->repo   = repo;
  	sm->branch = NULL;
  
  	*out = sm;
  	return 0;
  }
  
  static void submodule_release(git_submodule *sm)
  {
  	if (!sm)
  		return;
  
  	if (sm->repo) {
  		sm->repo = NULL;
  	}
  
  	if (sm->path != sm->name)
  		git__free(sm->path);
  	git__free(sm->name);
  	git__free(sm->url);
  	git__free(sm->branch);
  	git__memzero(sm, sizeof(*sm));
  	git__free(sm);
  }
  
  int git_submodule_dup(git_submodule **out, git_submodule *source)
  {
  	GIT_ASSERT_ARG(out);
  	GIT_ASSERT_ARG(source);
  
  	GIT_REFCOUNT_INC(source);
  
  	*out = source;
  	return 0;
  }
  
  void git_submodule_free(git_submodule *sm)
  {
  	if (!sm)
  		return;
  	GIT_REFCOUNT_DEC(sm, submodule_release);
  }
  
  static int submodule_config_error(const char *property, const char *value)
  {
  	git_error_set(GIT_ERROR_INVALID,
  		"invalid value for submodule '%s' property: '%s'", property, value);
  	return -1;
  }
  
  int git_submodule_parse_ignore(git_submodule_ignore_t *out, const char *value)
  {
  	int val;
  
  	if (git_config_lookup_map_value(
  			&val, _sm_ignore_map, ARRAY_SIZE(_sm_ignore_map), value) < 0) {
  		*out = GIT_SUBMODULE_IGNORE_NONE;
  		return submodule_config_error("ignore", value);
  	}
  
  	*out = (git_submodule_ignore_t)val;
  	return 0;
  }
  
  int git_submodule_parse_update(git_submodule_update_t *out, const char *value)
  {
  	int val;
  
  	if (git_config_lookup_map_value(
  			&val, _sm_update_map, ARRAY_SIZE(_sm_update_map), value) < 0) {
  		*out = GIT_SUBMODULE_UPDATE_CHECKOUT;
  		return submodule_config_error("update", value);
  	}
  
  	*out = (git_submodule_update_t)val;
  	return 0;
  }
  
  static int submodule_parse_recurse(git_submodule_recurse_t *out, const char *value)
  {
  	int val;
  
  	if (git_config_lookup_map_value(
  			&val, _sm_recurse_map, ARRAY_SIZE(_sm_recurse_map), value) < 0) {
  		*out = GIT_SUBMODULE_RECURSE_YES;
  		return submodule_config_error("recurse", value);
  	}
  
  	*out = (git_submodule_recurse_t)val;
  	return 0;
  }
  
  static int get_value(const char **out, git_config *cfg, git_buf *buf, const char *name, const char *field)
  {
  	int error;
  
  	git_buf_clear(buf);
  
  	if ((error = git_buf_printf(buf, "submodule.%s.%s", name, field)) < 0 ||
  	    (error = git_config_get_string(out, cfg, buf->ptr)) < 0)
  		return error;
  
  	return error;
  }
  
  static bool looks_like_command_line_option(const char *s)
  {
  	if (s && s[0] == '-')
  		return true;
  
  	return false;
  }
  
  static int submodule_read_config(git_submodule *sm, git_config *cfg)
  {
  	git_buf key = GIT_BUF_INIT;
  	const char *value;
  	int error, in_config = 0;
  
  	/*
  	 * TODO: Look up path in index and if it is present but not a GITLINK
  	 * then this should be deleted (at least to match git's behavior)
  	 */
  
  	if ((error = get_value(&value, cfg, &key, sm->name, "path")) == 0) {
  		in_config = 1;
  		/* We would warn here if we had that API */
  		if (!looks_like_command_line_option(value)) {
  	/*
  	 * TODO: if case insensitive filesystem, then the following strcmp
  	 * should be strcasecmp
  	 */
  			if (strcmp(sm->name, value) != 0) {
  				if (sm->path != sm->name)
  					git__free(sm->path);
  				sm->path = git__strdup(value);
  				GIT_ERROR_CHECK_ALLOC(sm->path);
  			}
  
  		}
  	} else if (error != GIT_ENOTFOUND) {
  		goto cleanup;
  	}
  
  	if ((error = get_value(&value, cfg, &key, sm->name, "url")) == 0) {
  		/* We would warn here if we had that API */
  		if (!looks_like_command_line_option(value)) {
  			in_config = 1;
  			sm->url = git__strdup(value);
  			GIT_ERROR_CHECK_ALLOC(sm->url);
  		}
  	} else if (error != GIT_ENOTFOUND) {
  		goto cleanup;
  	}
  
  	if ((error = get_value(&value, cfg, &key, sm->name, "branch")) == 0) {
  		in_config = 1;
  		sm->branch = git__strdup(value);
  		GIT_ERROR_CHECK_ALLOC(sm->branch);
  	} else if (error != GIT_ENOTFOUND) {
  		goto cleanup;
  	}
  
  	if ((error = get_value(&value, cfg, &key, sm->name, "update")) == 0) {
  		in_config = 1;
  		if ((error = git_submodule_parse_update(&sm->update, value)) < 0)
  			goto cleanup;
  		sm->update_default = sm->update;
  	} else if (error != GIT_ENOTFOUND) {
  		goto cleanup;
  	}
  
  	if ((error = get_value(&value, cfg, &key, sm->name, "fetchRecurseSubmodules")) == 0) {
  		in_config = 1;
  		if ((error = submodule_parse_recurse(&sm->fetch_recurse, value)) < 0)
  			goto cleanup;
  		sm->fetch_recurse_default = sm->fetch_recurse;
  	} else if (error != GIT_ENOTFOUND) {
  		goto cleanup;
  	}
  
  	if ((error = get_value(&value, cfg, &key, sm->name, "ignore")) == 0) {
  		in_config = 1;
  		if ((error = git_submodule_parse_ignore(&sm->ignore, value)) < 0)
  			goto cleanup;
  		sm->ignore_default = sm->ignore;
  	} else if (error != GIT_ENOTFOUND) {
  		goto cleanup;
  	}
  
  	if (in_config)
  		sm->flags |= GIT_SUBMODULE_STATUS_IN_CONFIG;
  
  	error = 0;
  
  cleanup:
  	git_buf_dispose(&key);
  	return error;
  }
  
  static int submodule_load_each(const git_config_entry *entry, void *payload)
  {
  	lfc_data *data = payload;
  	const char *namestart, *property;
  	git_strmap *map = data->map;
  	git_buf name = GIT_BUF_INIT;
  	git_submodule *sm;
  	int error, isvalid;
  
  	if (git__prefixcmp(entry->name, "submodule.") != 0)
  		return 0;
  
  	namestart = entry->name + strlen("submodule.");
  	property  = strrchr(namestart, '.');
  
  	if (!property || (property == namestart))
  		return 0;
  
  	property++;
  
  	if ((error = git_buf_set(&name, namestart, property - namestart -1)) < 0)
  		return error;
  
  	isvalid = git_submodule_name_is_valid(data->repo, name.ptr, 0);
  	if (isvalid <= 0) {
  		error = isvalid;
  		goto done;
  	}
  
  	/*
  	 * Now that we have the submodule's name, we can use that to
  	 * figure out whether it's in the map. If it's not, we create
  	 * a new submodule, load the config and insert it. If it's
  	 * already inserted, we've already loaded it, so we skip.
  	 */
  	if (git_strmap_exists(map, name.ptr)) {
  		error = 0;
  		goto done;
  	}
  
  	if ((error = submodule_alloc(&sm, data->repo, name.ptr)) < 0)
  		goto done;
  
  	if ((error = submodule_read_config(sm, data->mods)) < 0) {
  		git_submodule_free(sm);
  		goto done;
  	}
  
  	if ((error = git_strmap_set(map, sm->name, sm)) < 0)
  		goto done;
  
  	error = 0;
  
  done:
  	git_buf_dispose(&name);
  	return error;
  }
  
  static int submodule_load_from_wd_lite(git_submodule *sm)
  {
  	git_buf path = GIT_BUF_INIT;
  
  	if (git_repository_workdir_path(&path, sm->repo, sm->path) < 0)
  		return -1;
  
  	if (git_path_isdir(path.ptr))
  		sm->flags |= GIT_SUBMODULE_STATUS__WD_SCANNED;
  
  	if (git_path_contains(&path, DOT_GIT))
  		sm->flags |= GIT_SUBMODULE_STATUS_IN_WD;
  
  	git_buf_dispose(&path);
  	return 0;
  }
  
  /**
   * Requests a snapshot of $WORK_TREE/.gitmodules.
   *
   * Returns GIT_ENOTFOUND in case no .gitmodules file exist
   */
  static int gitmodules_snapshot(git_config **snap, git_repository *repo)
  {
  	git_config *mods = NULL;
  	git_buf path = GIT_BUF_INIT;
  	int error;
  
  	if (git_repository_workdir(repo) == NULL)
  		return GIT_ENOTFOUND;
  
  	if ((error = git_repository_workdir_path(&path, repo, GIT_MODULES_FILE)) < 0)
  		return error;
  
  	if ((error = git_config_open_ondisk(&mods, path.ptr)) < 0)
  		goto cleanup;
  	git_buf_dispose(&path);
  
  	if ((error = git_config_snapshot(snap, mods)) < 0)
  		goto cleanup;
  
  	error = 0;
  
  cleanup:
  	if (mods)
  		git_config_free(mods);
  	git_buf_dispose(&path);
  
  	return error;
  }
  
  static git_config_backend *open_gitmodules(
  	git_repository *repo,
  	int okay_to_create)
  {
  	git_buf path = GIT_BUF_INIT;
  	git_config_backend *mods = NULL;
  
  	if (git_repository_workdir(repo) != NULL) {
  		if (git_repository_workdir_path(&path, repo, GIT_MODULES_FILE) != 0)
  			return NULL;
  
  		if (okay_to_create || git_path_isfile(path.ptr)) {
  			/* git_config_backend_from_file should only fail if OOM */
  			if (git_config_backend_from_file(&mods, path.ptr) < 0)
  				mods = NULL;
  			/* open should only fail here if the file is malformed */
  			else if (git_config_backend_open(mods, GIT_CONFIG_LEVEL_LOCAL, repo) < 0) {
  				git_config_backend_free(mods);
  				mods = NULL;
  			}
  		}
  	}
  
  	git_buf_dispose(&path);
  
  	return mods;
  }
  
  /* Lookup name of remote of the local tracking branch HEAD points to */
  static int lookup_head_remote_key(git_buf *remote_name, git_repository *repo)
  {
  	int error;
  	git_reference *head = NULL;
  	git_buf upstream_name = GIT_BUF_INIT;
  
  	/* lookup and dereference HEAD */
  	if ((error = git_repository_head(&head, repo)) < 0)
  		return error;
  
  	/**
  	 * If head does not refer to a branch, then return
  	 * GIT_ENOTFOUND to indicate that we could not find
  	 * a remote key for the local tracking branch HEAD points to.
  	 **/
  	if (!git_reference_is_branch(head)) {
  		git_error_set(GIT_ERROR_INVALID,
  			"HEAD does not refer to a branch.");
  		error = GIT_ENOTFOUND;
  		goto done;
  	}
  
  	/* lookup remote tracking branch of HEAD */
  	if ((error = git_branch_upstream_name(
  		&upstream_name,
  		repo,
  		git_reference_name(head))) < 0)
  		goto done;
  
  	/* lookup remote of remote tracking branch */
  	if ((error = git_branch_remote_name(remote_name, repo, upstream_name.ptr)) < 0)
  		goto done;
  
  done:
  	git_buf_dispose(&upstream_name);
  	git_reference_free(head);
  
  	return error;
  }
  
  /* Lookup the remote of the local tracking branch HEAD points to */
  static int lookup_head_remote(git_remote **remote, git_repository *repo)
  {
  	int error;
  	git_buf remote_name = GIT_BUF_INIT;
  
  	/* lookup remote of remote tracking branch name */
  	if (!(error = lookup_head_remote_key(&remote_name, repo)))
  		error = git_remote_lookup(remote, repo, remote_name.ptr);
  
  	git_buf_dispose(&remote_name);
  
  	return error;
  }
  
  /* Lookup remote, either from HEAD or fall back on origin */
  static int lookup_default_remote(git_remote **remote, git_repository *repo)
  {
  	int error = lookup_head_remote(remote, repo);
  
  	/* if that failed, use 'origin' instead */
  	if (error == GIT_ENOTFOUND || error == GIT_EUNBORNBRANCH)
  		error = git_remote_lookup(remote, repo, "origin");
  
  	if (error == GIT_ENOTFOUND)
  		git_error_set(
  			GIT_ERROR_SUBMODULE,
  			"cannot get default remote for submodule - no local tracking "
  			"branch for HEAD and origin does not exist");
  
  	return error;
  }
  
  static int get_url_base(git_buf *url, git_repository *repo)
  {
  	int error;
  	git_worktree *wt = NULL;
  	git_remote *remote = NULL;
  
  	if ((error = lookup_default_remote(&remote, repo)) == 0) {
  		error = git_buf_sets(url, git_remote_url(remote));
  		goto out;
  	} else if (error != GIT_ENOTFOUND)
  		goto out;
  	else
  		git_error_clear();
  
  	/* if repository does not have a default remote, use workdir instead */
  	if (git_repository_is_worktree(repo)) {
  		if ((error = git_worktree_open_from_repository(&wt, repo)) < 0)
  			goto out;
  		error = git_buf_sets(url, wt->parent_path);
  	} else {
  		error = git_buf_sets(url, git_repository_workdir(repo));
  	}
  
  out:
  	git_remote_free(remote);
  	git_worktree_free(wt);
  
  	return error;
  }
  
  static void submodule_get_index_status(unsigned int *status, git_submodule *sm)
  {
  	const git_oid *head_oid  = git_submodule_head_id(sm);
  	const git_oid *index_oid = git_submodule_index_id(sm);
  
  	*status = *status & ~GIT_SUBMODULE_STATUS__INDEX_FLAGS;
  
  	if (!head_oid) {
  		if (index_oid)
  			*status |= GIT_SUBMODULE_STATUS_INDEX_ADDED;
  	}
  	else if (!index_oid)
  		*status |= GIT_SUBMODULE_STATUS_INDEX_DELETED;
  	else if (!git_oid_equal(head_oid, index_oid))
  		*status |= GIT_SUBMODULE_STATUS_INDEX_MODIFIED;
  }
  
  
  static void submodule_get_wd_status(
  	unsigned int *status,
  	git_submodule *sm,
  	git_repository *sm_repo,
  	git_submodule_ignore_t ign)
  {
  	const git_oid *index_oid = git_submodule_index_id(sm);
  	const git_oid *wd_oid =
  		(sm->flags & GIT_SUBMODULE_STATUS__WD_OID_VALID) ? &sm->wd_oid : NULL;
  	git_tree *sm_head = NULL;
  	git_index *index = NULL;
  	git_diff_options opt = GIT_DIFF_OPTIONS_INIT;
  	git_diff *diff;
  
  	*status = *status & ~GIT_SUBMODULE_STATUS__WD_FLAGS;
  
  	if (!index_oid) {
  		if (wd_oid)
  			*status |= GIT_SUBMODULE_STATUS_WD_ADDED;
  	}
  	else if (!wd_oid) {
  		if ((sm->flags & GIT_SUBMODULE_STATUS__WD_SCANNED) != 0 &&
  			(sm->flags & GIT_SUBMODULE_STATUS_IN_WD) == 0)
  			*status |= GIT_SUBMODULE_STATUS_WD_UNINITIALIZED;
  		else
  			*status |= GIT_SUBMODULE_STATUS_WD_DELETED;
  	}
  	else if (!git_oid_equal(index_oid, wd_oid))
  		*status |= GIT_SUBMODULE_STATUS_WD_MODIFIED;
  
  	/* if we have no repo, then we're done */
  	if (!sm_repo)
  		return;
  
  	/* the diffs below could be optimized with an early termination
  	 * option to the git_diff functions, but for now this is sufficient
  	 * (and certainly no worse that what core git does).
  	 */
  
  	if (ign == GIT_SUBMODULE_IGNORE_NONE)
  		opt.flags |= GIT_DIFF_INCLUDE_UNTRACKED;
  
  	(void)git_repository_index__weakptr(&index, sm_repo);
  
  	/* if we don't have an unborn head, check diff with index */
  	if (git_repository_head_tree(&sm_head, sm_repo) < 0)
  		git_error_clear();
  	else {
  		/* perform head to index diff on submodule */
  		if (git_diff_tree_to_index(&diff, sm_repo, sm_head, index, &opt) < 0)
  			git_error_clear();
  		else {
  			if (git_diff_num_deltas(diff) > 0)
  				*status |= GIT_SUBMODULE_STATUS_WD_INDEX_MODIFIED;
  			git_diff_free(diff);
  			diff = NULL;
  		}
  
  		git_tree_free(sm_head);
  	}
  
  	/* perform index-to-workdir diff on submodule */
  	if (git_diff_index_to_workdir(&diff, sm_repo, index, &opt) < 0)
  		git_error_clear();
  	else {
  		size_t untracked =
  			git_diff_num_deltas_of_type(diff, GIT_DELTA_UNTRACKED);
  
  		if (untracked > 0)
  			*status |= GIT_SUBMODULE_STATUS_WD_UNTRACKED;
  
  		if (git_diff_num_deltas(diff) != untracked)
  			*status |= GIT_SUBMODULE_STATUS_WD_WD_MODIFIED;
  
  		git_diff_free(diff);
  		diff = NULL;
  	}
  }
  

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