thodg/libgit2

diff --git a/src/attr.c b/src/attr.c
index a8848ca..86be084 100644
--- a/src/attr.c
+++ b/src/attr.c
@@ -253,28 +253,43 @@ cleanup:
 	return error;
 }
 
-static int preload_attr_file(
+static int preload_attr_source(
 	git_repository *repo,
 	git_attr_session *attr_session,
-	git_attr_file_source_t source_type,
-	const char *base,
-	const char *file,
-	bool allow_macros)
+	git_attr_file_source *source)
 {
 	int error;
 	git_attr_file *preload = NULL;
 
-	if (!file)
+	if (!source)
 		return 0;
-	if (!(error = git_attr_cache__get(&preload, repo, attr_session,
-	                                  source_type, base, file,
-	                                  git_attr_file__parse_buffer,
-	                                  allow_macros)))
+
+	error = git_attr_cache__get(&preload, repo, attr_session, source,
+	                            git_attr_file__parse_buffer, true);
+
+	if (!error)
 		git_attr_file__free(preload);
 
 	return error;
 }
 
+GIT_INLINE(int) preload_attr_file(
+	git_repository *repo,
+	git_attr_session *attr_session,
+	const char *base,
+	const char *filename)
+{
+	git_attr_file_source source = { GIT_ATTR_FILE_SOURCE_FILE };
+
+	if (!filename)
+		return 0;
+
+	source.base = base;
+	source.filename = filename;
+
+	return preload_attr_source(repo, attr_session, &source);
+}
+
 static int system_attr_file(
 	git_buf *out,
 	git_attr_session *attr_session)
@@ -318,7 +333,9 @@ static int attr_setup(
 	git_attr_session *attr_session,
 	uint32_t flags)
 {
-	git_buf path = GIT_BUF_INIT;
+	git_buf system = GIT_BUF_INIT, info = GIT_BUF_INIT;
+	git_attr_file_source index_source = { GIT_ATTR_FILE_SOURCE_INDEX, NULL, GIT_ATTR_FILE };
+	git_attr_file_source head_source = { GIT_ATTR_FILE_SOURCE_COMMIT, NULL, GIT_ATTR_FILE };
 	git_index *idx = NULL;
 	const char *workdir;
 	int error = 0;
@@ -334,45 +351,44 @@ static int attr_setup(
 	 * definitions will be available for later file parsing.
 	 */
 
-	if ((error = system_attr_file(&path, attr_session)) < 0 ||
-	    (error = preload_attr_file(repo, attr_session, GIT_ATTR_FILE_SOURCE_FILE,
-				       NULL, path.ptr, true)) < 0) {
+	if ((error = system_attr_file(&system, attr_session)) < 0 ||
+	    (error = preload_attr_file(repo, attr_session, NULL, system.ptr)) < 0) {
 		if (error != GIT_ENOTFOUND)
 			goto out;
+
+		error = 0;
 	}
 
-	if ((error = preload_attr_file(repo, attr_session, GIT_ATTR_FILE_SOURCE_FILE,
-				       NULL, git_repository_attr_cache(repo)->cfg_attr_file, true)) < 0)
+	if ((error = preload_attr_file(repo, attr_session, NULL,
+	                               git_repository_attr_cache(repo)->cfg_attr_file)) < 0)
 		goto out;
 
-	git_buf_clear(&path); /* git_repository_item_path expects an empty buffer, because it uses git_buf_set */
-	if ((error = git_repository_item_path(&path, repo, GIT_REPOSITORY_ITEM_INFO)) < 0 ||
-	    (error = preload_attr_file(repo, attr_session, GIT_ATTR_FILE_SOURCE_FILE,
-				       path.ptr, GIT_ATTR_FILE_INREPO, true)) < 0) {
+	if ((error = git_repository_item_path(&info, repo, GIT_REPOSITORY_ITEM_INFO)) < 0 ||
+	    (error = preload_attr_file(repo, attr_session, info.ptr, GIT_ATTR_FILE_INREPO)) < 0) {
 		if (error != GIT_ENOTFOUND)
 			goto out;
+
+		error = 0;
 	}
 
 	if ((workdir = git_repository_workdir(repo)) != NULL &&
-	    (error = preload_attr_file(repo, attr_session, GIT_ATTR_FILE_SOURCE_FILE,
-				       workdir, GIT_ATTR_FILE, true)) < 0)
+	    (error = preload_attr_file(repo, attr_session, workdir, GIT_ATTR_FILE)) < 0)
 			goto out;
 
 	if ((error = git_repository_index__weakptr(&idx, repo)) < 0 ||
-	    (error = preload_attr_file(repo, attr_session, GIT_ATTR_FILE_SOURCE_INDEX,
-				       NULL, GIT_ATTR_FILE, true)) < 0)
+	    (error = preload_attr_source(repo, attr_session, &index_source)) < 0)
 			goto out;
 
 	if ((flags & GIT_ATTR_CHECK_INCLUDE_HEAD) != 0 &&
-	    (error = preload_attr_file(repo, attr_session, GIT_ATTR_FILE_SOURCE_HEAD,
-				       NULL, GIT_ATTR_FILE, true)) < 0)
+	    (error = preload_attr_source(repo, attr_session, &head_source)) < 0)
 		goto out;
 
 	if (attr_session)
 		attr_session->init_setup = 1;
 
 out:
-	git_buf_dispose(&path);
+	git_buf_dispose(&system);
+	git_buf_dispose(&info);
 
 	return error;
 }
@@ -451,25 +467,23 @@ static int attr_decide_sources(
 	}
 
 	if ((flags & GIT_ATTR_CHECK_INCLUDE_HEAD) != 0)
-		srcs[count++] = GIT_ATTR_FILE_SOURCE_HEAD;
+		srcs[count++] = GIT_ATTR_FILE_SOURCE_COMMIT;
 
 	return count;
 }
 
-static int push_attr_file(
+static int push_attr_source(
 	git_repository *repo,
 	git_attr_session *attr_session,
 	git_vector *list,
-	git_attr_file_source_t source_type,
-	const char *base,
-	const char *filename,
+	git_attr_file_source *source,
 	bool allow_macros)
 {
 	int error = 0;
 	git_attr_file *file = NULL;
 
 	error = git_attr_cache__get(&file, repo, attr_session,
-	                            source_type, base, filename,
+	                            source,
 	                            git_attr_file__parse_buffer,
 	                            allow_macros);
 
@@ -484,6 +498,17 @@ static int push_attr_file(
 	return error;
 }
 
+GIT_INLINE(int) push_attr_file(
+	git_repository *repo,
+	git_attr_session *attr_session,
+	git_vector *list,
+	const char *base,
+	const char *filename)
+{
+	git_attr_file_source source = { GIT_ATTR_FILE_SOURCE_FILE, base, filename };
+	return push_attr_source(repo, attr_session, list, &source, true);
+}
+
 static int push_one_attr(void *ref, const char *path)
 {
 	attr_walk_up_info *info = (attr_walk_up_info *)ref;
@@ -495,9 +520,12 @@ static int push_one_attr(void *ref, const char *path)
 		info->flags, info->workdir != NULL, info->index != NULL, src);
 	allow_macros = info->workdir ? !strcmp(info->workdir, path) : false;
 
-	for (i = 0; !error && i < n_src; ++i)
-		error = push_attr_file(info->repo, info->attr_session, info->files,
-				       src[i], path, GIT_ATTR_FILE, allow_macros);
+	for (i = 0; !error && i < n_src; ++i) {
+		git_attr_file_source source = { src[i], path, GIT_ATTR_FILE };
+
+		error = push_attr_source(info->repo, info->attr_session, info->files,
+		                       &source, allow_macros);
+	}
 
 	return error;
 }
@@ -549,8 +577,7 @@ static int collect_attr_files(
 	 */
 
 	if ((error = git_repository_item_path(&attrfile, repo, GIT_REPOSITORY_ITEM_INFO)) < 0 ||
-	    (error = push_attr_file(repo, attr_session, files, GIT_ATTR_FILE_SOURCE_FILE,
-				    attrfile.ptr, GIT_ATTR_FILE_INREPO, true)) < 0) {
+	    (error = push_attr_file(repo, attr_session, files, attrfile.ptr, GIT_ATTR_FILE_INREPO)) < 0) {
 		if (error != GIT_ENOTFOUND)
 			goto cleanup;
 	}
@@ -572,8 +599,7 @@ static int collect_attr_files(
 		goto cleanup;
 
 	if (git_repository_attr_cache(repo)->cfg_attr_file != NULL) {
-		error = push_attr_file(repo, attr_session, files, GIT_ATTR_FILE_SOURCE_FILE,
-				       NULL, git_repository_attr_cache(repo)->cfg_attr_file, true);
+		error = push_attr_file(repo, attr_session, files, NULL, git_repository_attr_cache(repo)->cfg_attr_file);
 		if (error < 0)
 			goto cleanup;
 	}
@@ -582,8 +608,7 @@ static int collect_attr_files(
 		error = system_attr_file(&dir, attr_session);
 
 		if (!error)
-			error = push_attr_file(repo, attr_session, files, GIT_ATTR_FILE_SOURCE_FILE,
-					       NULL, dir.ptr, true);
+			error = push_attr_file(repo, attr_session, files, NULL, dir.ptr);
 		else if (error == GIT_ENOTFOUND)
 			error = 0;
 	}
diff --git a/src/attr_file.c b/src/attr_file.c
index db16a47..b586023 100644
--- a/src/attr_file.c
+++ b/src/attr_file.c
@@ -162,7 +162,7 @@ int git_attr_file__load(
 
 		break;
 	}
-	case GIT_ATTR_FILE_SOURCE_HEAD: {
+	case GIT_ATTR_FILE_SOURCE_COMMIT: {
 		if ((error = git_repository_head_tree(&tree, repo)) < 0 ||
 		    (error = git_tree_entry_bypath(&tree_entry, tree, entry->path)) < 0 ||
 		    (error = git_blob_lookup(&blob, repo, git_tree_entry_id(tree_entry))) < 0)
@@ -212,7 +212,7 @@ int git_attr_file__load(
 		file->nonexistent = 1;
 	else if (source->type == GIT_ATTR_FILE_SOURCE_INDEX)
 		git_oid_cpy(&file->cache_data.oid, git_blob_id(blob));
-	else if (source->type == GIT_ATTR_FILE_SOURCE_HEAD)
+	else if (source->type == GIT_ATTR_FILE_SOURCE_COMMIT)
 		git_oid_cpy(&file->cache_data.oid, git_tree_id(tree));
 	else if (source->type == GIT_ATTR_FILE_SOURCE_FILE)
 		git_futils_filestamp_set_from_stat(&file->cache_data.stamp, &st);
@@ -264,7 +264,7 @@ int git_attr_file__out_of_date(
 		return (git_oid__cmp(&file->cache_data.oid, &id) != 0);
 	}
 
-	case GIT_ATTR_FILE_SOURCE_HEAD: {
+	case GIT_ATTR_FILE_SOURCE_COMMIT: {
 		git_tree *tree;
 		int error;
 
diff --git a/src/attr_file.h b/src/attr_file.h
index 6f5318d..691dbda 100644
--- a/src/attr_file.h
+++ b/src/attr_file.h
@@ -40,13 +40,21 @@ typedef enum {
 	GIT_ATTR_FILE_SOURCE_MEMORY = 0,
 	GIT_ATTR_FILE_SOURCE_FILE   = 1,
 	GIT_ATTR_FILE_SOURCE_INDEX  = 2,
-	GIT_ATTR_FILE_SOURCE_HEAD   = 3,
+	GIT_ATTR_FILE_SOURCE_COMMIT = 3,
 
 	GIT_ATTR_FILE_NUM_SOURCES   = 4
 } git_attr_file_source_t;
 
 typedef struct {
+	/* The source location for the attribute file. */
 	git_attr_file_source_t type;
+
+	/*
+	 * The filename of the attribute file to read (relative to the
+	 * given base path).
+	 */
+	const char *base;
+	const char *filename;
 } git_attr_file_source;
 
 extern const char *git_attr__true;
diff --git a/src/attrcache.c b/src/attrcache.c
index 1f842c6..f077127 100644
--- a/src/attrcache.c
+++ b/src/attrcache.c
@@ -158,41 +158,42 @@ static int attr_cache_lookup(
 	git_attr_file_entry **out_entry,
 	git_repository *repo,
 	git_attr_session *attr_session,
-	git_attr_file_source_t source_type,
-	const char *base,
-	const char *filename)
+	git_attr_file_source *source)
 {
 	int error = 0;
 	git_buf path = GIT_BUF_INIT;
-	const char *wd = git_repository_workdir(repo), *relfile;
+	const char *wd = git_repository_workdir(repo);
+	const char *filename;
 	git_attr_cache *cache = git_repository_attr_cache(repo);
 	git_attr_file_entry *entry = NULL;
 	git_attr_file *file = NULL;
 
 	/* join base and path as needed */
-	if (base != NULL && git_path_root(filename) < 0) {
+	if (source->base != NULL && git_path_root(source->filename) < 0) {
 		git_buf *p = attr_session ? &attr_session->tmp : &path;
 
-		if (git_buf_joinpath(p, base, filename) < 0 ||
+		if (git_buf_joinpath(p, source->base, source->filename) < 0 ||
 		    git_path_validate_workdir_buf(repo, p) < 0)
 			return -1;
 
 		filename = p->ptr;
+	} else {
+		filename = source->filename;
 	}
 
-	relfile = filename;
-	if (wd && !git__prefixcmp(relfile, wd))
-		relfile += strlen(wd);
+	if (wd && !git__prefixcmp(filename, wd))
+		filename += strlen(wd);
 
 	/* check cache for existing entry */
 	if ((error = attr_cache_lock(cache)) < 0)
 		goto cleanup;
 
-	entry = attr_cache_lookup_entry(cache, relfile);
-	if (!entry)
-		error = attr_cache_make_entry(&entry, repo, relfile);
-	else if (entry->file[source_type] != NULL) {
-		file = entry->file[source_type];
+	entry = attr_cache_lookup_entry(cache, filename);
+
+	if (!entry) {
+		error = attr_cache_make_entry(&entry, repo, filename);
+	} else if (entry->file[source->type] != NULL) {
+		file = entry->file[source->type];
 		GIT_REFCOUNT_INC(file);
 	}
 
@@ -210,9 +211,7 @@ int git_attr_cache__get(
 	git_attr_file **out,
 	git_repository *repo,
 	git_attr_session *attr_session,
-	git_attr_file_source_t source_type,
-	const char *base,
-	const char *filename,
+	git_attr_file_source *source,
 	git_attr_file_parser parser,
 	bool allow_macros)
 {
@@ -220,16 +219,14 @@ int git_attr_cache__get(
 	git_attr_cache *cache = git_repository_attr_cache(repo);
 	git_attr_file_entry *entry = NULL;
 	git_attr_file *file = NULL, *updated = NULL;
-	git_attr_file_source source = { source_type };
 
-	if ((error = attr_cache_lookup(&file, &entry, repo, attr_session,
-	                               source_type, base, filename)) < 0)
+	if ((error = attr_cache_lookup(&file, &entry, repo, attr_session, source)) < 0)
 		return error;
 
 	/* load file if we don't have one or if existing one is out of date */
 	if (!file || (error = git_attr_file__out_of_date(repo, attr_session, file)) > 0)
 		error = git_attr_file__load(&updated, repo, attr_session,
-		                            entry, &source, parser,
+		                            entry, source, parser,
 		                            allow_macros);
 
 	/* if we loaded the file, insert into and/or update cache */
diff --git a/src/attrcache.h b/src/attrcache.h
index 6d1d968..b13e0e8 100644
--- a/src/attrcache.h
+++ b/src/attrcache.h
@@ -31,16 +31,14 @@ extern int git_attr_cache__get(
 	git_attr_file **file,
 	git_repository *repo,
 	git_attr_session *attr_session,
-	git_attr_file_source_t source_type,
-	const char *base,
-	const char *filename,
+	git_attr_file_source *source,
 	git_attr_file_parser parser,
 	bool allow_macros);
 
 extern bool git_attr_cache__is_cached(
 	git_repository *repo,
 	git_attr_file_source_t source_type,
-	const char *path);
+	const char *filename);
 
 extern int git_attr_cache__alloc_file_entry(
 	git_attr_file_entry **out,
diff --git a/src/ignore.c b/src/ignore.c
index db34289..f7551cd 100644
--- a/src/ignore.c
+++ b/src/ignore.c
@@ -247,12 +247,11 @@ static int push_ignore_file(
 	const char *base,
 	const char *filename)
 {
-	int error = 0;
+	git_attr_file_source source = { GIT_ATTR_FILE_SOURCE_FILE, base, filename };
 	git_attr_file *file = NULL;
+	int error = 0;
 
-	error = git_attr_cache__get(&file, ignores->repo, NULL,
-	                            GIT_ATTR_FILE_SOURCE_FILE, base,
-				    filename, parse_ignore_file, false);
+	error = git_attr_cache__get(&file, ignores->repo, NULL, &source, parse_ignore_file, false);
 
 	if (error < 0)
 		return error;
@@ -274,14 +273,13 @@ static int push_one_ignore(void *payload, const char *path)
 
 static int get_internal_ignores(git_attr_file **out, git_repository *repo)
 {
+	git_attr_file_source source = { GIT_ATTR_FILE_SOURCE_MEMORY, NULL, GIT_IGNORE_INTERNAL };
 	int error;
 
 	if ((error = git_attr_cache__init(repo)) < 0)
 		return error;
 
-	error = git_attr_cache__get(out, repo, NULL,
-	                            GIT_ATTR_FILE_SOURCE_MEMORY, NULL,
-	                            GIT_IGNORE_INTERNAL, NULL, false);
+	error = git_attr_cache__get(out, repo, NULL, &source, NULL, false);
 
 	/* if internal rules list is empty, insert default rules */
 	if (!error && !(*out)->rules.length)