Replace the data writer enqueue with "append buffer to current file"

This commit turns the file interface into an actual, generic file
interface and does away with having to move around blocks outside
the data writer. Instead the data writer takes over full control
and responsibility of dividing the input data up into blocks
propperly.

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

3 files changed, 61 insertions, 20 deletions

diff --git a/lib/sqfs/data_writer/common.c b/lib/sqfs/data_writer/common.c
index c9d5589..9e11e36 100644
--- a/lib/sqfs/data_writer/common.c
+++ b/lib/sqfs/data_writer/common.c
@@ -47,6 +47,7 @@ void data_writer_cleanup(sqfs_data_writer_t *proc)
 {
 	free_blk_list(proc->queue);
 	free_blk_list(proc->done);
+	free(proc->blk_current);
 	free(proc->frag_block);
 	free(proc->frag_list);
 	free(proc->fragments);
diff --git a/lib/sqfs/data_writer/fileapi.c b/lib/sqfs/data_writer/fileapi.c
index b78d012..712fd29 100644
--- a/lib/sqfs/data_writer/fileapi.c
+++ b/lib/sqfs/data_writer/fileapi.c
@@ -35,16 +35,14 @@ int sqfs_data_writer_begin_file(sqfs_data_writer_t *proc,
 		return test_and_set_status(proc, SQFS_ERROR_UNSUPPORTED);
 
 	proc->inode = inode;
-	proc->blk_flags = flags;
+	proc->blk_flags = flags | SQFS_BLK_FIRST_BLOCK;
 	proc->blk_index = 0;
-	proc->had_fragment = false;
+	proc->blk_current = NULL;
 	return 0;
 }
 
-int sqfs_data_writer_enqueue(sqfs_data_writer_t *proc, sqfs_block_t *block)
+static int flush_block(sqfs_data_writer_t *proc, sqfs_block_t *block)
 {
-	int err;
-
 	block->index = proc->blk_index++;
 	block->flags = proc->blk_flags;
 	block->inode = proc->inode;
@@ -59,25 +57,63 @@ int sqfs_data_writer_enqueue(sqfs_data_writer_t *proc, sqfs_block_t *block)
 	}
 
 	if (block->size < proc->max_block_size) {
-		if (block->index > 0) {
-			err = add_sentinel_block(proc);
+		block->flags |= SQFS_BLK_IS_FRAGMENT;
+	} else {
+		proc->inode->num_file_blocks += 1;
+		proc->blk_flags &= ~SQFS_BLK_FIRST_BLOCK;
+	}
+
+	return data_writer_enqueue(proc, block);
+}
+
+int sqfs_data_writer_append(sqfs_data_writer_t *proc, const void *data,
+			    size_t size)
+{
+	size_t diff;
+	void *new;
+	int err;
+
+	while (size > 0) {
+		if (proc->blk_current == NULL) {
+			new = alloc_flex(sizeof(*proc->blk_current), 1,
+					 proc->max_block_size);
+
+			if (new == NULL)
+				return test_and_set_status(proc,
+							   SQFS_ERROR_ALLOC);
 
-			if (err) {
-				free(block);
+			proc->blk_current = new;
+		}
+
+		diff = proc->max_block_size - proc->blk_current->size;
+
+		if (diff == 0) {
+			err = flush_block(proc, proc->blk_current);
+			proc->blk_current = NULL;
+			if (err)
 				return err;
-			}
+			continue;
 		}
 
-		proc->had_fragment = true;
-		block->flags |= SQFS_BLK_IS_FRAGMENT;
-	} else {
-		if (block->index == 0)
-			block->flags |= SQFS_BLK_FIRST_BLOCK;
+		if (diff > size)
+			diff = size;
 
-		proc->inode->num_file_blocks += 1;
+		memcpy(proc->blk_current->data + proc->blk_current->size,
+		       data, diff);
+
+		size -= diff;
+		proc->blk_current->size += diff;
+		data = (const char *)data + diff;
 	}
 
-	return data_writer_enqueue(proc, block);
+	if (proc->blk_current != NULL &&
+	    proc->blk_current->size == proc->max_block_size) {
+		err = flush_block(proc, proc->blk_current);
+		proc->blk_current = NULL;
+		return err;
+	}
+
+	return 0;
 }
 
 int sqfs_data_writer_end_file(sqfs_data_writer_t *proc)
@@ -87,15 +123,19 @@ int sqfs_data_writer_end_file(sqfs_data_writer_t *proc)
 	if (proc->inode == NULL)
 		return test_and_set_status(proc, SQFS_ERROR_INTERNAL);
 
-	if (!proc->had_fragment && proc->inode->num_file_blocks > 0) {
+	if (!(proc->blk_flags & SQFS_BLK_FIRST_BLOCK)) {
 		err = add_sentinel_block(proc);
 		if (err)
 			return err;
 	}
 
+	if (proc->blk_current != NULL) {
+		err = flush_block(proc, proc->blk_current);
+		proc->blk_current = NULL;
+	}
+
 	proc->inode = NULL;
 	proc->blk_flags = 0;
 	proc->blk_index = 0;
-	proc->had_fragment = false;
 	return 0;
 }
diff --git a/lib/sqfs/data_writer/internal.h b/lib/sqfs/data_writer/internal.h
index 9072c19..1aa600b 100644
--- a/lib/sqfs/data_writer/internal.h
+++ b/lib/sqfs/data_writer/internal.h
@@ -103,9 +103,9 @@ struct sqfs_data_writer_t {
 
 	/* file API */
 	sqfs_inode_generic_t *inode;
+	sqfs_block_t *blk_current;
 	uint32_t blk_flags;
 	size_t blk_index;
-	bool had_fragment;
 
 	/* used only by workers */
 	size_t max_block_size;