Add file API stub to sqfs data writer

Basically move the state tracking from the old data writer over to
the new one.

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

1 files changed, 101 insertions, 0 deletions

diff --git a/lib/sqfs/data_writer/fileapi.c b/lib/sqfs/data_writer/fileapi.c
new file mode 100644
index 0000000..b78d012
--- /dev/null
+++ b/lib/sqfs/data_writer/fileapi.c
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * fileapi.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "internal.h"
+
+static bool is_zero_block(unsigned char *ptr, size_t size)
+{
+	return ptr[0] == 0 && memcmp(ptr, ptr + 1, size - 1) == 0;
+}
+
+static int add_sentinel_block(sqfs_data_writer_t *proc)
+{
+	sqfs_block_t *blk = calloc(1, sizeof(*blk));
+
+	if (blk == NULL)
+		return test_and_set_status(proc, SQFS_ERROR_ALLOC);
+
+	blk->inode = proc->inode;
+	blk->flags = proc->blk_flags | SQFS_BLK_LAST_BLOCK;
+
+	return data_writer_enqueue(proc, blk);
+}
+
+int sqfs_data_writer_begin_file(sqfs_data_writer_t *proc,
+				sqfs_inode_generic_t *inode, uint32_t flags)
+{
+	if (proc->inode != NULL)
+		return test_and_set_status(proc, SQFS_ERROR_INTERNAL);
+
+	if (flags & ~SQFS_BLK_USER_SETTABLE_FLAGS)
+		return test_and_set_status(proc, SQFS_ERROR_UNSUPPORTED);
+
+	proc->inode = inode;
+	proc->blk_flags = flags;
+	proc->blk_index = 0;
+	proc->had_fragment = false;
+	return 0;
+}
+
+int sqfs_data_writer_enqueue(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;
+
+	if (is_zero_block(block->data, block->size)) {
+		sqfs_inode_make_extended(proc->inode);
+		proc->inode->data.file_ext.sparse += block->size;
+		proc->inode->num_file_blocks += 1;
+		proc->inode->block_sizes[block->index] = 0;
+		free(block);
+		return 0;
+	}
+
+	if (block->size < proc->max_block_size) {
+		if (block->index > 0) {
+			err = add_sentinel_block(proc);
+
+			if (err) {
+				free(block);
+				return err;
+			}
+		}
+
+		proc->had_fragment = true;
+		block->flags |= SQFS_BLK_IS_FRAGMENT;
+	} else {
+		if (block->index == 0)
+			block->flags |= SQFS_BLK_FIRST_BLOCK;
+
+		proc->inode->num_file_blocks += 1;
+	}
+
+	return data_writer_enqueue(proc, block);
+}
+
+int sqfs_data_writer_end_file(sqfs_data_writer_t *proc)
+{
+	int err;
+
+	if (proc->inode == NULL)
+		return test_and_set_status(proc, SQFS_ERROR_INTERNAL);
+
+	if (!proc->had_fragment && proc->inode->num_file_blocks > 0) {
+		err = add_sentinel_block(proc);
+		if (err)
+			return err;
+	}
+
+	proc->inode = NULL;
+	proc->blk_flags = 0;
+	proc->blk_index = 0;
+	proc->had_fragment = false;
+	return 0;
+}