libcommon: get rid of write_data_from_file

Modify gensquashfs to pack data using an istream wrapper, similar
to tar2sqfs. To implement the no-tail-pack option, we need the file
size, so we simply open a raw handle first, and query it (using
libsquashfs API) and then create the stream wrapper. For the output
side, we create a block-processor ostream wrapper and splice it.

Since gensquashfs is the only, remaining user of the pack-a-file
functon, we can then remove it from libcommon.

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

4 files changed, 48 insertions, 79 deletions

diff --git a/bin/gensquashfs/src/mkfs.c b/bin/gensquashfs/src/mkfs.c
index 6d04040..248eb74 100644
--- a/bin/gensquashfs/src/mkfs.c
+++ b/bin/gensquashfs/src/mkfs.c
@@ -6,13 +6,56 @@
  */
 #include "mkfs.h"
 
+static int pack_file(sqfs_block_processor_t *data,
+		     const char *path, tree_node_t *n, const options_t *opt)
+{
+	sqfs_ostream_t *out = NULL;
+	sqfs_istream_t *in = NULL;
+	sqfs_file_handle_t hnd;
+	sqfs_u64 filesize;
+	int ret, flags;
+
+	ret = sqfs_native_file_open(&hnd, path, SQFS_FILE_OPEN_READ_ONLY);
+	if (ret)
+		goto done;
+
+	ret = sqfs_native_file_get_size(hnd, &filesize);
+	if (ret)
+		goto done;
+
+	ret = sqfs_istream_open_handle(&in, path, hnd, 0);
+	if (ret)
+		goto done;
+
+	flags = n->data.file.flags;
+	if (opt->no_tail_packing && filesize > opt->cfg.block_size)
+		flags |= SQFS_BLK_DONT_FRAGMENT;
+
+	ret = sqfs_block_processor_create_ostream(&out, path, data,
+						  &(n->data.file.inode), flags);
+	if (ret)
+		goto done;
+
+	do {
+		ret = sqfs_istream_splice(in, out, opt->cfg.block_size);
+	} while (ret > 0);
+
+	if (ret == 0)
+		ret = out->flush(out);
+done:
+	if (ret)
+		sqfs_perror(path, NULL, ret);
+	if (in == NULL)
+		sqfs_native_file_close(hnd);
+	sqfs_drop(out);
+	sqfs_drop(in);
+	return ret;
+}
+
 static int pack_files(sqfs_block_processor_t *data, fstree_t *fs,
 		      options_t *opt)
 {
-	sqfs_u64 filesize;
-	sqfs_file_t *file;
 	tree_node_t *node;
-	int flags;
 	int ret;
 
 	if (opt->packdir != NULL && chdir(opt->packdir) != 0) {
@@ -40,22 +83,7 @@ static int pack_files(sqfs_block_processor_t *data, fstree_t *fs,
 		if (!opt->cfg.quiet)
 			printf("packing %s\n", path);
 
-		ret = sqfs_file_open(&file, path, SQFS_FILE_OPEN_READ_ONLY);
-		if (ret) {
-			sqfs_perror(path, "open", ret);
-			free(node_path);
-			return -1;
-		}
-
-		flags = node->data.file.flags;
-		filesize = file->get_size(file);
-
-		if (opt->no_tail_packing && filesize > opt->cfg.block_size)
-			flags |= SQFS_BLK_DONT_FRAGMENT;
-
-		ret = write_data_from_file(path, data, &(node->data.file.inode),
-					   file, flags);
-		sqfs_drop(file);
+		ret = pack_file(data, path, node, opt);
 		free(node_path);
 
 		if (ret)
diff --git a/include/common.h b/include/common.h
index 707d46b..bf3f34c 100644
--- a/include/common.h
+++ b/include/common.h
@@ -33,10 +33,6 @@ typedef struct sqfs_hard_link_t {
 	char *target;
 } sqfs_hard_link_t;
 
-int write_data_from_file(const char *filename, sqfs_block_processor_t *data,
-			 sqfs_inode_generic_t **inode,
-			 sqfs_file_t *file, int flags);
-
 void sqfs_perror(const char *file, const char *action, int error_code);
 
 int sqfs_tree_find_hard_links(const sqfs_tree_node_t *root,
diff --git a/lib/common/Makemodule.am b/lib/common/Makemodule.am
index e0cc551..a50ddcb 100644
--- a/lib/common/Makemodule.am
+++ b/lib/common/Makemodule.am
@@ -1,8 +1,7 @@
 libcommon_a_SOURCES = include/common.h include/simple_writer.h \
 	include/compress_cli.h \
 	lib/common/src/hardlink.c lib/common/src/print_version.c \
-	lib/common/src/compress.c \
-	lib/common/src/comp_opt.c lib/common/src/data_writer.c \
+	lib/common/src/compress.c lib/common/src/comp_opt.c \
 	lib/common/src/parse_size.c lib/common/src/print_size.c \
 	lib/common/src/writer/init.c lib/common/src/writer/cleanup.c \
 	lib/common/src/writer/serialize_fstree.c lib/common/src/writer/finish.c\
diff --git a/lib/common/src/data_writer.c b/lib/common/src/data_writer.c
deleted file mode 100644
index ceccaac..0000000
--- a/lib/common/src/data_writer.c
+++ /dev/null
@@ -1,54 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * data_writer.c
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#include "common.h"
-
-static sqfs_u8 buffer[4096];
-
-int write_data_from_file(const char *filename, sqfs_block_processor_t *data,
-			 sqfs_inode_generic_t **inode, sqfs_file_t *file,
-			 int flags)
-{
-	sqfs_u64 filesz, offset;
-	size_t diff;
-	int ret;
-
-	ret = sqfs_block_processor_begin_file(data, inode, NULL, flags);
-	if (ret) {
-		sqfs_perror(filename, "beginning file data blocks", ret);
-		return -1;
-	}
-
-	filesz = file->get_size(file);
-
-	for (offset = 0; offset < filesz; offset += diff) {
-		if (filesz - offset > sizeof(buffer)) {
-			diff = sizeof(buffer);
-		} else {
-			diff = filesz - offset;
-		}
-
-		ret = file->read_at(file, offset, buffer, diff);
-		if (ret) {
-			sqfs_perror(filename, "reading file range", ret);
-			return -1;
-		}
-
-		ret = sqfs_block_processor_append(data, buffer, diff);
-		if (ret) {
-			sqfs_perror(filename, "packing file data", ret);
-			return -1;
-		}
-	}
-
-	ret = sqfs_block_processor_end_file(data);
-	if (ret) {
-		sqfs_perror(filename, "finishing file data", ret);
-		return -1;
-	}
-
-	return 0;
-}