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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* Chunk I/O
* =========
* Copyright 2018 Eduardo Silva <eduardo@monkey.io>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE
#include <string.h>
#include <chunkio/chunkio_compat.h>
#include <chunkio/chunkio.h>
#include <chunkio/cio_file.h>
#include <chunkio/cio_file_st.h>
#include <chunkio/cio_memfs.h>
#include <chunkio/cio_stream.h>
#include <chunkio/cio_log.h>
/*
* Metadata is an optional information stored before the content of each file
* and can be used for different purposes. Manipulating metadata can have
* some performance impacts depending on 'when' it's added and how often
* is modified.
*
* For performance reasons, we suggest the metadata be stored before to write
* any data to the content area, otherwise if metadata grows in terms of bytes
* we need to move all the content data to a different position which is not
* ideal.
*
* The caller might want to fix the performance penalties setting up some
* empty metadata with specific sizes.
*/
int cio_meta_write(struct cio_chunk *ch, char *buf, size_t size)
{
struct cio_memfs *mf;
if (size > 65535) {
return -1;
}
if (ch->st->type == CIO_STORE_MEM) {
mf = (struct cio_memfs *) ch->backend;
if (mf->meta_data) {
free(mf->meta_data);
}
mf->meta_data = malloc(size);
if (!mf->meta_data) {
cio_errno();
return -1;
}
memcpy(mf->meta_data, buf, size);
mf->meta_len = size;
return 0;
}
else if (ch->st->type == CIO_STORE_FS) {
return cio_file_write_metadata(ch, buf, size);
}
return -1;
}
int cio_meta_size(struct cio_chunk *ch) {
if (ch->st->type == CIO_STORE_MEM) {
struct cio_memfs *mf = (struct cio_memfs *) ch->backend;
return mf->meta_len;
}
else if (ch->st->type == CIO_STORE_FS) {
if (cio_file_read_prepare(ch->ctx, ch)) {
return -1;
}
struct cio_file *cf = ch->backend;
return cio_file_st_get_meta_len(cf->map);
}
return -1;
}
int cio_meta_read(struct cio_chunk *ch, char **meta_buf, int *meta_len)
{
int len;
char *meta;
struct cio_file *cf;
struct cio_memfs *mf;
/* In-memory type */
if (ch->st->type == CIO_STORE_MEM) {
mf = (struct cio_memfs *) ch->backend;
/* no metadata */
if (!mf->meta_data) {
return -1;
}
*meta_buf = mf->meta_data;
*meta_len = mf->meta_len;
return 0;
}
else if (ch->st->type == CIO_STORE_FS) {
if (cio_file_read_prepare(ch->ctx, ch)) {
return -1;
}
cf = ch->backend;
len = cio_file_st_get_meta_len(cf->map);
if (len <= 0) {
return -1;
}
meta = cio_file_st_get_meta(cf->map);
*meta_buf = meta;
*meta_len = len;
return 0;
}
return -1;
}
int cio_meta_cmp(struct cio_chunk *ch, char *meta_buf, int meta_len)
{
int len;
char *meta;
struct cio_file *cf = ch->backend;
struct cio_memfs *mf;
/* In-memory type */
if (ch->st->type == CIO_STORE_MEM) {
mf = (struct cio_memfs *) ch->backend;
/* no metadata */
if (!mf->meta_data) {
return -1;
}
/* different lengths */
if (mf->meta_len != meta_len) {
return -1;
}
/* perfect match */
if (memcmp(mf->meta_data, meta_buf, meta_len) == 0) {
return 0;
}
return -1;
}
if (cio_file_read_prepare(ch->ctx, ch)) {
return -1;
}
/* File system type */
len = cio_file_st_get_meta_len(cf->map);
if (len != meta_len) {
return -1;
}
/* compare metadata */
meta = cio_file_st_get_meta(cf->map);
if (memcmp(meta, meta_buf, meta_len) == 0) {
return 0;
}
return -1;
}
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