Support associating a user pointer with data blocks

This commit modifies the block processor to support associating a user
data pointer with data blocks that it forwards to the block writer,
which is modified to accept an optional user data pointer.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

7 files changed, 26 insertions, 10 deletions

diff --git a/include/sqfs/block_processor.h b/include/sqfs/block_processor.h
index c88e3df..5c77155 100644
--- a/include/sqfs/block_processor.h
+++ b/include/sqfs/block_processor.h
@@ -168,6 +168,8 @@ sqfs_block_processor_t *sqfs_block_processor_create(size_t max_block_size,
  * @param inode An optional pointer to a pointer to an inode. If not NULL, the
  *              block processor creates a file inode and stores a pointer to
  *              it here and keeps updating the inode as the file grows.
+ * @param user An optional user data pointer that is passed to the
+ *             the @ref sqfs_block_writer_t for each file data block.
  * @param flags A combination of @ref SQFS_BLK_FLAGS that can be used to
  *              micro manage how the data is processed.
  *
@@ -175,7 +177,7 @@ sqfs_block_processor_t *sqfs_block_processor_create(size_t max_block_size,
  */
 SQFS_API int sqfs_block_processor_begin_file(sqfs_block_processor_t *proc,
 					     sqfs_inode_generic_t **inode,
-					     sqfs_u32 flags);
+					     void *user, sqfs_u32 flags);
 
 /**
  * @brief Append data to the current file.
diff --git a/include/sqfs/block_writer.h b/include/sqfs/block_writer.h
index f8bc671..6352f4d 100644
--- a/include/sqfs/block_writer.h
+++ b/include/sqfs/block_writer.h
@@ -58,6 +58,9 @@ struct sqfs_block_writer_t {
 	 * @ref SQFS_BLK_LAST_BLOCK flag, the padding is added afterwards.
 	 *
 	 * @param wr A pointer to a block writer.
+	 * @param user An optional user data pointer.
+	 *             The @ref sqfs_block_processor_t can be told to pass this
+	 *             on to the block writer for each block.
 	 * @param size The size of the block to write.
 	 * @param checksum A 32 bit checksum of the block data.
 	 * @param flags A combination of @ref SQFS_BLK_FLAGS flag bits
@@ -70,9 +73,10 @@ struct sqfs_block_writer_t {
 	 *
 	 * @return Zero on success, an @ref SQFS_ERROR error on failure.
 	 */
-	int (*write_data_block)(sqfs_block_writer_t *wr, sqfs_u32 size,
-				sqfs_u32 checksum, sqfs_u32 flags,
-				const sqfs_u8 *data, sqfs_u64 *location);
+	int (*write_data_block)(sqfs_block_writer_t *wr, void *user,
+				sqfs_u32 size, sqfs_u32 checksum,
+				sqfs_u32 flags, const sqfs_u8 *data,
+				sqfs_u64 *location);
 
 	/**
 	 * @brief Get the number of blocks actually written to disk.
diff --git a/lib/common/data_writer.c b/lib/common/data_writer.c
index bc5a43b..ceccaac 100644
--- a/lib/common/data_writer.c
+++ b/lib/common/data_writer.c
@@ -16,7 +16,7 @@ int write_data_from_file(const char *filename, sqfs_block_processor_t *data,
 	size_t diff;
 	int ret;
 
-	ret = sqfs_block_processor_begin_file(data, inode, flags);
+	ret = sqfs_block_processor_begin_file(data, inode, NULL, flags);
 	if (ret) {
 		sqfs_perror(filename, "beginning file data blocks", ret);
 		return -1;
diff --git a/lib/sqfs/block_processor/common.c b/lib/sqfs/block_processor/common.c
index 6a62d4f..bfcc3d5 100644
--- a/lib/sqfs/block_processor/common.c
+++ b/lib/sqfs/block_processor/common.c
@@ -69,8 +69,9 @@ static int process_completed_block(sqfs_block_processor_t *proc,
 	sqfs_u32 size;
 	int err;
 
-	err = proc->wr->write_data_block(proc->wr, blk->size, blk->checksum,
-					 blk->flags, blk->data, &location);
+	err = proc->wr->write_data_block(proc->wr, blk->user, blk->size,
+					 blk->checksum, blk->flags,
+					 blk->data, &location);
 	if (err)
 		goto out;
 
diff --git a/lib/sqfs/block_processor/frontend.c b/lib/sqfs/block_processor/frontend.c
index 8381dd8..d6571ea 100644
--- a/lib/sqfs/block_processor/frontend.c
+++ b/lib/sqfs/block_processor/frontend.c
@@ -55,7 +55,8 @@ static int flush_block(sqfs_block_processor_t *proc)
 }
 
 int sqfs_block_processor_begin_file(sqfs_block_processor_t *proc,
-				    sqfs_inode_generic_t **inode, sqfs_u32 flags)
+				    sqfs_inode_generic_t **inode,
+				    void *user, sqfs_u32 flags)
 {
 	if (proc->begin_called)
 		return SQFS_ERROR_SEQUENCE;
@@ -76,6 +77,7 @@ int sqfs_block_processor_begin_file(sqfs_block_processor_t *proc,
 	proc->inode = inode;
 	proc->blk_flags = flags | SQFS_BLK_FIRST_BLOCK;
 	proc->blk_index = 0;
+	proc->user = user;
 	return 0;
 }
 
@@ -104,6 +106,7 @@ int sqfs_block_processor_append(sqfs_block_processor_t *proc, const void *data,
 			proc->blk_current = new;
 			proc->blk_current->flags = proc->blk_flags;
 			proc->blk_current->inode = proc->inode;
+			proc->blk_current->user = proc->user;
 		}
 
 		diff = proc->max_block_size - proc->blk_current->size;
@@ -162,6 +165,7 @@ int sqfs_block_processor_end_file(sqfs_block_processor_t *proc)
 
 	proc->begin_called = false;
 	proc->inode = NULL;
+	proc->user = NULL;
 	proc->blk_flags = 0;
 	return 0;
 }
diff --git a/lib/sqfs/block_processor/internal.h b/lib/sqfs/block_processor/internal.h
index 61e13d7..d28e023 100644
--- a/lib/sqfs/block_processor/internal.h
+++ b/lib/sqfs/block_processor/internal.h
@@ -42,6 +42,9 @@ typedef struct sqfs_block_t {
 	   consolidate in reverse order. */
 	struct sqfs_block_t *frag_list;
 
+	/* User data pointer */
+	void *user;
+
 	sqfs_u8 data[];
 } sqfs_block_t;
 
@@ -59,6 +62,7 @@ struct sqfs_block_processor_t {
 	sqfs_block_t *blk_current;
 	sqfs_u32 blk_flags;
 	sqfs_u32 blk_index;
+	void *user;
 
 	sqfs_block_t *free_list;
 
diff --git a/lib/sqfs/block_writer.c b/lib/sqfs/block_writer.c
index a6ca4b3..07780d7 100644
--- a/lib/sqfs/block_writer.c
+++ b/lib/sqfs/block_writer.c
@@ -115,8 +115,8 @@ static void block_writer_destroy(sqfs_object_t *wr)
 	free(wr);
 }
 
-static int write_data_block(sqfs_block_writer_t *base, sqfs_u32 size,
-			    sqfs_u32 checksum, sqfs_u32 flags,
+static int write_data_block(sqfs_block_writer_t *base, void *user,
+			    sqfs_u32 size, sqfs_u32 checksum, sqfs_u32 flags,
 			    const sqfs_u8 *data, sqfs_u64 *location)
 {
 	block_writer_default_t *wr = (block_writer_default_t *)base;
@@ -124,6 +124,7 @@ static int write_data_block(sqfs_block_writer_t *base, sqfs_u32 size,
 	sqfs_u64 offset;
 	sqfs_u32 out;
 	int err;
+	(void)user;
 
 	if (flags & SQFS_BLK_FIRST_BLOCK) {
 		wr->start = wr->file->get_size(wr->file);