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#include "cache.h"
#include "chunk-format.h"
#include "csum-file.h"
/*
* When writing a chunk-based file format, collect the chunks in
* an array of chunk_info structs. The size stores the _expected_
* amount of data that will be written by write_fn.
*/
struct chunk_info {
uint32_t id;
uint64_t size;
chunk_write_fn write_fn;
const void *start;
};
struct chunkfile {
struct hashfile *f;
struct chunk_info *chunks;
size_t chunks_nr;
size_t chunks_alloc;
};
struct chunkfile *init_chunkfile(struct hashfile *f)
{
struct chunkfile *cf = xcalloc(1, sizeof(*cf));
cf->f = f;
return cf;
}
void free_chunkfile(struct chunkfile *cf)
{
if (!cf)
return;
free(cf->chunks);
free(cf);
}
int get_num_chunks(struct chunkfile *cf)
{
return cf->chunks_nr;
}
void add_chunk(struct chunkfile *cf,
uint32_t id,
size_t size,
chunk_write_fn fn)
{
ALLOC_GROW(cf->chunks, cf->chunks_nr + 1, cf->chunks_alloc);
cf->chunks[cf->chunks_nr].id = id;
cf->chunks[cf->chunks_nr].write_fn = fn;
cf->chunks[cf->chunks_nr].size = size;
cf->chunks_nr++;
}
int write_chunkfile(struct chunkfile *cf, void *data)
{
int i, result = 0;
uint64_t cur_offset = hashfile_total(cf->f);
trace2_region_enter("chunkfile", "write", the_repository);
/* Add the table of contents to the current offset */
cur_offset += (cf->chunks_nr + 1) * CHUNK_TOC_ENTRY_SIZE;
for (i = 0; i < cf->chunks_nr; i++) {
hashwrite_be32(cf->f, cf->chunks[i].id);
hashwrite_be64(cf->f, cur_offset);
cur_offset += cf->chunks[i].size;
}
/* Trailing entry marks the end of the chunks */
hashwrite_be32(cf->f, 0);
hashwrite_be64(cf->f, cur_offset);
for (i = 0; i < cf->chunks_nr; i++) {
off_t start_offset = hashfile_total(cf->f);
result = cf->chunks[i].write_fn(cf->f, data);
if (result)
goto cleanup;
if (hashfile_total(cf->f) - start_offset != cf->chunks[i].size)
BUG("expected to write %"PRId64" bytes to chunk %"PRIx32", but wrote %"PRId64" instead",
cf->chunks[i].size, cf->chunks[i].id,
hashfile_total(cf->f) - start_offset);
}
cleanup:
trace2_region_leave("chunkfile", "write", the_repository);
return result;
}
int read_table_of_contents(struct chunkfile *cf,
const unsigned char *mfile,
size_t mfile_size,
uint64_t toc_offset,
int toc_length)
{
int i;
uint32_t chunk_id;
const unsigned char *table_of_contents = mfile + toc_offset;
ALLOC_GROW(cf->chunks, toc_length, cf->chunks_alloc);
while (toc_length--) {
uint64_t chunk_offset, next_chunk_offset;
chunk_id = get_be32(table_of_contents);
chunk_offset = get_be64(table_of_contents + 4);
if (!chunk_id) {
error(_("terminating chunk id appears earlier than expected"));
return 1;
}
table_of_contents += CHUNK_TOC_ENTRY_SIZE;
next_chunk_offset = get_be64(table_of_contents + 4);
if (next_chunk_offset < chunk_offset ||
next_chunk_offset > mfile_size - the_hash_algo->rawsz) {
error(_("improper chunk offset(s) %"PRIx64" and %"PRIx64""),
chunk_offset, next_chunk_offset);
return -1;
}
for (i = 0; i < cf->chunks_nr; i++) {
if (cf->chunks[i].id == chunk_id) {
error(_("duplicate chunk ID %"PRIx32" found"),
chunk_id);
return -1;
}
}
cf->chunks[cf->chunks_nr].id = chunk_id;
cf->chunks[cf->chunks_nr].start = mfile + chunk_offset;
cf->chunks[cf->chunks_nr].size = next_chunk_offset - chunk_offset;
cf->chunks_nr++;
}
chunk_id = get_be32(table_of_contents);
if (chunk_id) {
error(_("final chunk has non-zero id %"PRIx32""), chunk_id);
return -1;
}
return 0;
}
static int pair_chunk_fn(const unsigned char *chunk_start,
size_t chunk_size,
void *data)
{
const unsigned char **p = data;
*p = chunk_start;
return 0;
}
int pair_chunk(struct chunkfile *cf,
uint32_t chunk_id,
const unsigned char **p)
{
return read_chunk(cf, chunk_id, pair_chunk_fn, p);
}
int read_chunk(struct chunkfile *cf,
uint32_t chunk_id,
chunk_read_fn fn,
void *data)
{
int i;
for (i = 0; i < cf->chunks_nr; i++) {
if (cf->chunks[i].id == chunk_id)
return fn(cf->chunks[i].start, cf->chunks[i].size, data);
}
return CHUNK_NOT_FOUND;
}