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

common/dynamic_partition_control_interface.h

diff --git a/common/dynamic_partition_control_interface.h b/common/dynamic_partition_control_interface.h
index 22f6db8..530b0af 100644
--- a/common/dynamic_partition_control_interface.h
+++ b/common/dynamic_partition_control_interface.h
@@ -26,8 +26,14 @@
 #include "update_engine/common/action.h"
 #include "update_engine/common/cleanup_previous_update_action_delegate.h"
 #include "update_engine/common/error_code.h"
+#include "update_engine/payload_consumer/file_descriptor.h"
 #include "update_engine/update_metadata.pb.h"
 
+// Forware declare for libsnapshot/snapshot_writer.h
+namespace android::snapshot {
+class ISnapshotWriter;
+}
+
 namespace chromeos_update_engine {
 
 struct FeatureFlag {
@@ -139,6 +145,15 @@
       uint32_t source_slot,
       uint32_t target_slot,
       const std::vector<std::string>& partitions) = 0;
+  // Partition name is expected to be unsuffixed. e.g. system, vendor
+  // Return an interface to write to a snapshoted partition.
+  // If `is_append` is false, then existing COW data will be overwritten.
+  // Otherwise the cow writer will be opened on APPEND mode, existing COW data
+  // is preserved.
+  virtual std::unique_ptr<android::snapshot::ISnapshotWriter> OpenCowWriter(
+      const std::string& unsuffixed_partition_name,
+      const std::optional<std::string>&,
+      bool is_append = false) = 0;
 };
 
 }  // namespace chromeos_update_engine

common/dynamic_partition_control_stub.cc

diff --git a/common/dynamic_partition_control_stub.cc b/common/dynamic_partition_control_stub.cc
index c63a8ff..64ab201 100644
--- a/common/dynamic_partition_control_stub.cc
+++ b/common/dynamic_partition_control_stub.cc
@@ -20,6 +20,7 @@
 #include <string>
 
 #include <base/logging.h>
+#include <libsnapshot/cow_writer.h>
 
 #include "update_engine/common/dynamic_partition_control_stub.h"
 
@@ -87,4 +88,12 @@
   return true;
 }
 
+std::unique_ptr<android::snapshot::ISnapshotWriter>
+DynamicPartitionControlStub::OpenCowWriter(
+    const std::string& /*unsuffixed_partition_name*/,
+    const std::optional<std::string>& /*source_path*/,
+    bool /*is_append*/) {
+  return nullptr;
+}
+
 }  // namespace chromeos_update_engine

common/dynamic_partition_control_stub.h

diff --git a/common/dynamic_partition_control_stub.h b/common/dynamic_partition_control_stub.h
index 8bff474..a939cfb 100644
--- a/common/dynamic_partition_control_stub.h
+++ b/common/dynamic_partition_control_stub.h
@@ -57,8 +57,12 @@
       uint32_t source_slot,
       uint32_t target_slot,
       const std::vector<std::string>& partitions) override;
-};
 
+  std::unique_ptr<android::snapshot::ISnapshotWriter> OpenCowWriter(
+      const std::string& unsuffixed_partition_name,
+      const std::optional<std::string>&,
+      bool is_append) override;
+};
 }  // namespace chromeos_update_engine
 
 #endif  // UPDATE_ENGINE_COMMON_DYNAMIC_PARTITION_CONTROL_STUB_H_