diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/sqfs/data_writer.h | 98 | ||||
| -rw-r--r-- | include/sqfs/predef.h | 1 |
2 files changed, 99 insertions, 0 deletions
diff --git a/include/sqfs/data_writer.h b/include/sqfs/data_writer.h index 3f1ad02..cc99700 100644 --- a/include/sqfs/data_writer.h +++ b/include/sqfs/data_writer.h @@ -42,6 +42,91 @@ * is called for each one. */ +/** + * @struct sqfs_block_hooks_t + * + * @brief A set of hooks for tapping into the data writer. + * + * This structure can be registered with an @ref sqfs_data_writer_t and + * contains function pointers that will be called during various stages + * when writing data to disk. + * + * The callbacks can not only be used for accounting but may also write extra + * data to the output file or make modifications to the blocks before they are + * writtien. + * + * The callbacks can be individually set to NULL to disable them. + */ +struct sqfs_block_hooks_t { + /** + * @brief Gets called before writing a block to disk. + * + * If this is not NULL, it gets called before a block is written to + * disk. If the block has the @ref SQFS_BLK_ALLIGN flag set, the + * function is called before padding the file. + * + * The function may modify the block itself or write data to the file. + * which is taken into account when padding the file. + * + * @param user A user pointer. + * @param block The block that is about to be written. + * @param file The file that the block will be written to. + */ + void (*pre_block_write)(void *user, sqfs_block_t *block, + sqfs_file_t *file); + + /** + * @brief Gets called after writing a block to disk. + * + * If this is not NULL, it gets called after a block is written to + * disk. If the block has the @ref SQFS_BLK_ALLIGN flag set, the + * function is called before padding the file. + * + * Modifying the block is rather pointless, but the function may + * write data to the file which is taken into account when padding + * the file. + * + * @param user A user pointer. + * @param block The block that is about to be written. + * @param file The file that the block was written to. + */ + void (*post_block_write)(void *user, const sqfs_block_t *block, + sqfs_file_t *file); + + /** + * @brief Gets called before storing a fragment in a fragment block. + * + * The function can modify the block before it is stored. + * + * @param user A user pointer. + * @param block The data chunk that is about to be merged into the + * fragment block. + */ + void (*pre_fragment_store)(void *user, sqfs_block_t *block); + + /** + * @brief Gets called if block deduplication managed to get + * rid of the data blocks of a file. + * + * @param user A user pointer. + * @param count The number of blocks that have been erased. + * @param bytes The number of bytes that have been erased. Includes + * potential padding before and after the end. + */ + void (*notify_blocks_erased)(void *user, size_t count, + uint64_t bytes); + + /** + * @brief Gets called before throwing away a fragment that turned out + * to be a duplicate. + * + * @param user A user pointer. + * @param block The data chunk that is about to be merged into the + * fragment block. + */ + void (*notify_fragment_discard)(void *user, const sqfs_block_t *block); +}; + #ifdef __cplusplus extern "C" { #endif @@ -134,6 +219,19 @@ SQFS_API int sqfs_data_writer_write_fragment_table(sqfs_data_writer_t *proc, sqfs_super_t *super); +/** + * @brief Register a set of hooks to be invoked when writing blocks to disk. + * + * @memberof sqfs_data_writer_t + * + * @param proc A pointer to a data writer object. + * @param user_ptr A user pointer to pass to the callbacks. + * @param hooks A structure containing the hooks. + */ +SQFS_API +void sqfs_data_writer_set_hooks(sqfs_data_writer_t *proc, void *user_ptr, + const sqfs_block_hooks_t *hooks); + #ifdef __cplusplus } #endif diff --git a/include/sqfs/predef.h b/include/sqfs/predef.h index c94ca29..8a554dd 100644 --- a/include/sqfs/predef.h +++ b/include/sqfs/predef.h @@ -72,6 +72,7 @@ typedef struct sqfs_file_t sqfs_file_t; typedef struct sqfs_sparse_map_t sqfs_sparse_map_t; typedef struct sqfs_tree_node_t sqfs_tree_node_t; typedef struct sqfs_data_reader_t sqfs_data_reader_t; +typedef struct sqfs_block_hooks_t sqfs_block_hooks_t; typedef struct sqfs_fragment_t sqfs_fragment_t; typedef struct sqfs_dir_header_t sqfs_dir_header_t; |