commit 34618521d487a37d21f25812f324380f1eb394a8
author Kelvin Zhang <zhangkelvin@google.com> Mon Sep 28 09:21:02 2020 -0400
committer Kelvin Zhang <zhangkelvin@google.com> Fri Oct 23 09:52:19 2020 -0400
tree 45107761577a19fda261d73a6dfc1bba30d2e48d
parent 19e55297ac3805c7109325ea7d536887e302403e

Add CowWriter interface methods to DynamicPartiitonControl

Test: treehugger
Change-Id: I110c65e75a4594af51e68390e570ac31b50de8b5

dynamic_partition_control_android.cc

diff --git a/dynamic_partition_control_android.cc b/dynamic_partition_control_android.cc
index 1fb2c25..06e5745 100644
--- a/dynamic_partition_control_android.cc
+++ b/dynamic_partition_control_android.cc
@@ -17,6 +17,7 @@
 #include "update_engine/dynamic_partition_control_android.h"
 
 #include <chrono>  // NOLINT(build/c++11) - using libsnapshot / liblp API
+#include <cstdint>
 #include <map>
 #include <memory>
 #include <set>
@@ -36,6 +37,8 @@
 #include <fs_mgr_overlayfs.h>
 #include <libavb/libavb.h>
 #include <libdm/dm.h>
+#include <liblp/liblp.h>
+#include <libsnapshot/cow_writer.h>
 #include <libsnapshot/snapshot.h>
 #include <libsnapshot/snapshot_stub.h>
 
@@ -1230,4 +1233,30 @@
   return metadata_device_ != nullptr;
 }
 
+std::unique_ptr<android::snapshot::ISnapshotWriter>
+DynamicPartitionControlAndroid::OpenCowWriter(
+    const std::string& partition_name,
+    const std::optional<std::string>& source_path,
+    bool is_append) {
+  auto suffix = SlotSuffixForSlotNumber(target_slot_);
+
+  std::string device_dir_str;
+  if (!GetDeviceDir(&device_dir_str)) {
+    LOG(ERROR) << "Failed to get device dir!";
+    return nullptr;
+  }
+  base::FilePath device_dir(device_dir_str);
+  auto super_device =
+      device_dir.Append(GetSuperPartitionName(target_slot_)).value();
+  CreateLogicalPartitionParams params = {
+      .block_device = super_device,
+      .metadata_slot = target_slot_,
+      .partition_name = partition_name + suffix,
+      .force_writable = true,
+  };
+  // TODO(zhangkelvin) Open an APPEND mode CowWriter once there's an API to do
+  // it.
+  return snapshot_->OpenSnapshotWriter(params, std::move(source_path));
+}
+
 }  // namespace chromeos_update_engine