update_engine: Introduce FilesystemInterface abstraction.
The interaction with the filesystem in the payload generation process
is hard-coded in several places, making it hard to mock out or use a
different filesystem like squashfs for delta generation. For example,
the metadata, regular file data and non-file data are handled by three
different functions in a similar way, but with different code.
This patch introcudes a filesystem abstraction to map files or
pseudo-files (like the metadata, free-space, etc) into the same interface.
The interface includes three implementations: for parsing ext2 filesystems
using ext2fs (already used by the metadata parsing but not by the file
data processing), a raw one for monolitic partitions like the kernel
and a fake one used for testing without requiring to build/parse a real
ext2 filesystem.
BUG=chromium:331965
TEST=FEATURES=test emerge-link update_engine
Change-Id: I1e14cf8f3883c8e9a1d471c8193c8da60776aa7c
Reviewed-on: https://chromium-review.googlesource.com/275803
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Tested-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/payload_generator/raw_filesystem.cc b/payload_generator/raw_filesystem.cc
new file mode 100644
index 0000000..ee4423e
--- /dev/null
+++ b/payload_generator/raw_filesystem.cc
@@ -0,0 +1,41 @@
+// Copyright 2015 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "update_engine/payload_generator/raw_filesystem.h"
+
+#include "update_engine/extent_ranges.h"
+#include "update_engine/update_metadata.pb.h"
+#include "update_engine/utils.h"
+
+using std::unique_ptr;
+
+namespace chromeos_update_engine {
+
+unique_ptr<RawFilesystem> RawFilesystem::Create(
+ const std::string& filename, uint64_t block_size, uint64_t block_count) {
+ unique_ptr<RawFilesystem> result(new RawFilesystem());
+ result->filename_ = filename;
+ result->block_size_ = block_size;
+ result->block_count_ = block_count;
+ return result;
+}
+
+size_t RawFilesystem::GetBlockSize() const {
+ return block_size_;
+}
+
+size_t RawFilesystem::GetBlockCount() const {
+ return block_count_;
+}
+
+bool RawFilesystem::GetFiles(std::vector<File>* files) const {
+ files->clear();
+ File file;
+ file.name = filename_;
+ file.extents = { ExtentForRange(0, block_count_) };
+ files->push_back(file);
+ return true;
+}
+
+} // namespace chromeos_update_engine