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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2021-01-06 14:24:15 +0100
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2021-01-19 04:03:37 +0100
commit405d133e7f0dc0f92f54f08ef6078208028448a1 (patch)
treeb0a5ffca40f50f5c6a1c7e322434e9c0d4936a0e /include/sqfs
parentfe70d543c448ccb1adfb9a5d948820dc2c9d1e61 (diff)
libsqfs: Add a sqfs_block_processor_create_ex function
This function creates a block processor from a structure describing it. A stub implementation for the old sqfs_block_processor_create is added that simply sets up such a struct and forwards the call. The current version of the description struct only contains the exact same parameters and a size field at the beginning. This approach is supposed to make extending the range of parameters easier without breaking ABI compatibillity. Currently already planned are: - Adding a sqfs_file_t pointer to double-check when deduplicating fragments. - When the scanning code reaches a usable state, add the abillity to pass scanned fragment data, so the block processor can be used for appending to an existing image. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'include/sqfs')
-rw-r--r--include/sqfs/block_processor.h98
-rw-r--r--include/sqfs/predef.h1
2 files changed, 97 insertions, 2 deletions
diff --git a/include/sqfs/block_processor.h b/include/sqfs/block_processor.h
index 1846069..a5eed33 100644
--- a/include/sqfs/block_processor.h
+++ b/include/sqfs/block_processor.h
@@ -110,12 +110,90 @@ struct sqfs_block_processor_stats_t {
sqfs_u64 actual_frag_count;
};
+/**
+ * @struct sqfs_block_processor_desc_t
+ *
+ * @brief Encapsulates a description for an @ref sqfs_block_processor_t
+ *
+ * An instance of this struct is used by @ref sqfs_block_processor_create_ex to
+ * instantiate block processor objects.
+ */
+struct sqfs_block_processor_desc_t {
+ /**
+ * @brief Holds the size of the structure.
+ *
+ * If a later version of libsquashfs expands this structure, the value
+ * of this field can be used to check at runtime whether the newer
+ * fields are avaialable or not.
+ *
+ * If @ref sqfs_block_processor_create_ex is given a struct whose size
+ * it does not recognize, it returns @ref SQFS_ERROR_ARG_INVALID.
+ */
+ sqfs_u32 size;
+
+ /**
+ * @brief The maximum size of a data block.
+ */
+ sqfs_u32 max_block_size;
+
+ /**
+ * @brief The number of worker threads to create.
+ */
+ sqfs_u32 num_workers;
+
+ /**
+ * @brief The maximum number of blocks currently in flight.
+ *
+ * When trying to add more, enqueueing blocks until the
+ * in-flight block count drops below the threshold.
+ */
+ sqfs_u32 max_backlog;
+
+ /**
+ * @brief A pointer to a compressor.
+ *
+ * If multiple worker threads are used, the deep copy function of the
+ * compressor is used to create several instances that don't interfere
+ * with each other. This means, the compressor implementation must be
+ * able to create copies of itself that can be used independendly and
+ * concurrently.
+ */
+ sqfs_compressor_t *cmp;
+
+ /**
+ * @brief A block writer to send to finished blocks to.
+ */
+ sqfs_block_writer_t *wr;
+
+ /**
+ * @brief A fragment table to use for storing block locations.
+ */
+ sqfs_frag_table_t *tbl;
+
+ /**
+ * @brief Pointer to a file to read back fragment blocks from.
+ *
+ * If file and uncmp are not NULL, the file is used to read back
+ * fragment blocks during fragment deduplication and verify possible
+ * matches. If either of them are NULL, the deduplication relies on
+ * fragment size and hash alone.
+ */
+ sqfs_file_t *file;
+
+ /**
+ * @brief A pointer to a compressor the decompresses data.
+ *
+ * @copydoc file
+ */
+ sqfs_compressor_t *uncmp;
+};
+
#ifdef __cplusplus
extern "C" {
#endif
/**
- * @brief Create a data block writer.
+ * @brief Create a data block processor.
*
* @memberof sqfs_block_processor_t
*
@@ -132,7 +210,7 @@ extern "C" {
* @param tbl A fragment table to use for storing fragment and fragment block
* locations.
*
- * @return A pointer to a data writer object on success, NULL on allocation
+ * @return A pointer to a block processor object on success, NULL on allocation
* failure or on failure to create and initialize the worker threads.
*/
SQFS_API
@@ -144,6 +222,22 @@ sqfs_block_processor_t *sqfs_block_processor_create(size_t max_block_size,
sqfs_frag_table_t *tbl);
/**
+ * @brief Create a data block processor.
+ *
+ * @memberof sqfs_block_processor_t
+ *
+ * @param desc A pointer to an extensible structure that holds the description
+ * of the block processor.
+ * @param out On success, returns the pointer to the newly created block
+ * processor object.
+ *
+ * @return Zero on success, an @ref SQFS_ERROR value on failure.
+ */
+SQFS_API
+int sqfs_block_processor_create_ex(const sqfs_block_processor_desc_t *desc,
+ sqfs_block_processor_t **out);
+
+/**
* @brief Start writing a file.
*
* @memberof sqfs_block_processor_t
diff --git a/include/sqfs/predef.h b/include/sqfs/predef.h
index e0afac4..55ccc86 100644
--- a/include/sqfs/predef.h
+++ b/include/sqfs/predef.h
@@ -91,6 +91,7 @@ typedef struct sqfs_frag_table_t sqfs_frag_table_t;
typedef struct sqfs_block_writer_t sqfs_block_writer_t;
typedef struct sqfs_block_writer_stats_t sqfs_block_writer_stats_t;
typedef struct sqfs_block_processor_stats_t sqfs_block_processor_stats_t;
+typedef struct sqfs_block_processor_desc_t sqfs_block_processor_desc_t;
typedef struct sqfs_fragment_t sqfs_fragment_t;
typedef struct sqfs_dir_header_t sqfs_dir_header_t;