/*
 * This file is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2,
 * as published by the Free Software Foundation.
 *
 * In addition to the permissions in the GNU General Public License,
 * the authors give you unlimited permission to link the compiled
 * version of this file into combinations with other programs,
 * and to distribute those combinations without any restriction
 * coming from the use of this file.  (The General Public License
 * restrictions do apply in other respects; for example, they cover
 * modification of the file, and distribution when not linked into
 * a combined executable.)
 *
 * This file is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "common.h"
#include "commit.h"
#include "revwalk.h"
#include "tree.h"

void git_tree__free(git_tree *tree)
{
	free(tree);
}

const git_oid *git_tree_id(git_tree *tree)
{
	return &tree->object.id;
}

git_tree *git_tree_lookup(git_revpool *pool, const git_oid *id)
{
	git_tree *tree = NULL;

	if (pool == NULL)
		return NULL;

	tree = (git_tree *)git_revpool_table_lookup(pool->objects, id);
	if (tree != NULL)
		return tree;

	tree = git__malloc(sizeof(git_tree));

	if (tree == NULL)
		return NULL;

	memset(tree, 0x0, sizeof(git_tree));

	/* Initialize parent object */
	git_oid_cpy(&tree->object.id, id);
	tree->object.pool = pool;
	tree->object.type = GIT_OBJ_TREE;

	git_revpool_table_insert(pool->objects, (git_revpool_object *)tree);

	return tree;
}


git_tree *git_tree_parse(git_revpool *pool, const git_oid *id)
{
	git_tree *tree = NULL;

	if ((tree = git_tree_lookup(pool, id)) == NULL)
		return NULL;

	if (git_tree__parse(tree) < 0)
		goto error_cleanup;

	return tree;

error_cleanup:
	/* FIXME: do not free; the tree is owned by the revpool */
	free(tree);
	return NULL;
}

int git_tree__parse(git_tree *tree)
{
	static const char tree_header[] = {'t', 'r', 'e', 'e', ' '};

	int error = 0;
	git_obj odb_object;
	char *buffer, *buffer_end;

	error = git_odb_read(&odb_object, tree->object.pool->db, &tree->object.id);
	if (error < 0)
		return error;

	buffer = odb_object.data;
	buffer_end = odb_object.data + odb_object.len;

	if (memcmp(buffer, tree_header, 5) != 0)
		return GIT_EOBJCORRUPTED;

	buffer += 5;

	tree->byte_size = strtol(buffer, &buffer, 10);

	if (*buffer++ != 0)
		return GIT_EOBJCORRUPTED;

	while (buffer < buffer_end) {
		git_tree_entry *entry;

		entry = git__malloc(sizeof(git_tree_entry));
		entry->next = tree->entries;

		entry->attr = strtol(buffer, &buffer, 10);

		if (*buffer++ != ' ') {
			error = GIT_EOBJCORRUPTED;
			break;
		}

		entry->filename = git__strdup(buffer);

		if (entry->filename == NULL) {
			error = GIT_EOBJCORRUPTED;
			break;
		}
		buffer += strlen(entry->filename);

		git_oid_mkraw(&entry->oid, (const unsigned char *)buffer);
		buffer += GIT_OID_RAWSZ;

		tree->entries = entry;
	}

	return error;
}