diff options
| -rw-r--r-- | Makefile | 1 | ||||
| -rw-r--r-- | chunk-format.c | 90 | ||||
| -rw-r--r-- | chunk-format.h | 21 |
3 files changed, 112 insertions, 0 deletions
@@ -854,6 +854,7 @@ LIB_OBJS += bundle.o LIB_OBJS += cache-tree.o LIB_OBJS += chdir-notify.o LIB_OBJS += checkout.o +LIB_OBJS += chunk-format.o LIB_OBJS += color.o LIB_OBJS += column.o LIB_OBJS += combine-diff.o diff --git a/chunk-format.c b/chunk-format.c new file mode 100644 index 0000000000..6c9b52b70c --- /dev/null +++ b/chunk-format.c @@ -0,0 +1,90 @@ +#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; +}; + +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; + uint64_t cur_offset = hashfile_total(cf->f); + + /* 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); + int result = cf->chunks[i].write_fn(cf->f, data); + + if (result) + return result; + + 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); + } + + return 0; +} diff --git a/chunk-format.h b/chunk-format.h new file mode 100644 index 0000000000..ce598b66d9 --- /dev/null +++ b/chunk-format.h @@ -0,0 +1,21 @@ +#ifndef CHUNK_FORMAT_H +#define CHUNK_FORMAT_H + +#include "git-compat-util.h" + +struct hashfile; +struct chunkfile; + +#define CHUNK_TOC_ENTRY_SIZE (sizeof(uint32_t) + sizeof(uint64_t)) + +struct chunkfile *init_chunkfile(struct hashfile *f); +void free_chunkfile(struct chunkfile *cf); +int get_num_chunks(struct chunkfile *cf); +typedef int (*chunk_write_fn)(struct hashfile *f, void *data); +void add_chunk(struct chunkfile *cf, + uint32_t id, + size_t size, + chunk_write_fn fn); +int write_chunkfile(struct chunkfile *cf, void *data); + +#endif |