/*-
 * Copyright (c) 2008-2011 Juan Romero Pardines.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <zlib.h>
#include <xbps_api.h>
#include "xbps_api_impl.h"

/*
 * Takes a compressed data buffer, decompresses it and returns the
 * new buffer uncompressed if all was right.
 */
#define _READ_CHUNK	512

static char *
_xbps_uncompress_plist_data(char *xml, size_t len)
{
	z_stream strm;
	unsigned char out[_READ_CHUNK];
	char *uncomp_xml = NULL;
	size_t have;
	ssize_t totalsize = 0;
	int rv = 0;

	assert(xml != NULL);

	/* Decompress the mmap'ed buffer with zlib */
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;
	strm.avail_in = 0;
	strm.next_in = Z_NULL;

	/* 15+16 to use gzip method */
	if (inflateInit2(&strm, 15+16) != Z_OK)
		return NULL;

	strm.avail_in = len;
	strm.next_in = (unsigned char *)xml;

	/* Output buffer (uncompressed) */
	uncomp_xml = malloc(_READ_CHUNK);
	if (uncomp_xml == NULL) {
		(void)inflateEnd(&strm);
		return NULL;
	}

	/* Inflate the input buffer and copy into 'uncomp_xml' */
	do {
		strm.avail_out = _READ_CHUNK;
		strm.next_out = out;
		rv = inflate(&strm, Z_NO_FLUSH);
		switch (rv) {
		case Z_DATA_ERROR:
			/*
			 * Wrong compressed data or uncompressed, try
			 * normal method as last resort.
			 */
			(void)inflateEnd(&strm);
			free(uncomp_xml);
			errno = EAGAIN;
			return NULL;
		case Z_STREAM_ERROR:
		case Z_NEED_DICT:
		case Z_MEM_ERROR:
			(void)inflateEnd(&strm);
			free(uncomp_xml);
			return NULL;
		}
		have = _READ_CHUNK - strm.avail_out;
		totalsize += have;
		uncomp_xml = realloc(uncomp_xml, totalsize);
		memcpy(uncomp_xml + totalsize - have, out, have);
	} while (strm.avail_out == 0);

	/* we are done */
	(void)inflateEnd(&strm);

	return uncomp_xml;
}
#undef _READ_CHUNK

prop_dictionary_t HIDDEN
xbps_read_dict_from_archive_entry(struct archive *ar,
				  struct archive_entry *entry)
{
	prop_dictionary_t d = NULL;
	size_t buflen = 0;
	ssize_t nbytes = -1;
	char *buf, *uncomp_buf;

	assert(ar != NULL);
	assert(entry != NULL);

	buflen = (size_t)archive_entry_size(entry);
	buf = malloc(buflen);
	if (buf == NULL)
		return NULL;

	nbytes = archive_read_data(ar, buf, buflen);
	if ((size_t)nbytes != buflen) {
		free(buf);
		return NULL;
	}

	uncomp_buf = _xbps_uncompress_plist_data(buf, buflen);
	if (uncomp_buf == NULL) {
		if (errno && errno != EAGAIN) {
			/* Error while decompressing */
			free(buf);
			return NULL;
		} else if (errno == EAGAIN) {
			/* Not a compressed data, try again */
			errno = 0;
			d = prop_dictionary_internalize(buf);
			free(buf);
		}
	} else {
		/* We have the uncompressed data */
		d = prop_dictionary_internalize(uncomp_buf);
		free(uncomp_buf);
		free(buf);
	}

	if (d == NULL)
		return NULL;
	else if (prop_object_type(d) != PROP_TYPE_DICTIONARY) {
		prop_object_release(d);
		return NULL;
	}

	return d;
}