AU: Start checkpointing update progress.

delta_performer.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__
 
 #include <inttypes.h>
 
 #include <vector>
 
 #include <google/protobuf/repeated_field.h>
 
 #include "update_engine/file_writer.h"
 #include "update_engine/omaha_hash_calculator.h"
 #include "update_engine/update_metadata.pb.h"
 
 namespace chromeos_update_engine {
 
+class PrefsInterface;
+
 // This class performs the actions in a delta update synchronously. The delta
 // update itself should be passed in in chunks as it is received.
 
 class DeltaPerformer : public FileWriter {
  public:
-  DeltaPerformer()
-      : fd_(-1),
+  DeltaPerformer(PrefsInterface* prefs)
+      : prefs_(prefs),
+        fd_(-1),
         kernel_fd_(-1),
         manifest_valid_(false),
         next_operation_num_(0),
         buffer_offset_(0),
         block_size_(0) {}
 
   // Opens the kernel. Should be called before or after Open(), but before
   // Write(). The kernel file will be close()d when Close() is called.
   bool OpenKernel(const char* kernel_path);
 
@@ skipping 55 matching lines @@
 
   // Returns true if the payload signature message has been extracted from
   // |operation|, false otherwise.
   bool ExtractSignatureMessage(
       const DeltaArchiveManifest_InstallOperation& operation);
 
   // Discard |count| bytes from the beginning of buffer_. If |do_hash| is true,
   // updates the hash calculator with these bytes before discarding them.
   void DiscardBufferHeadBytes(size_t count, bool do_hash);
 
+  bool ResetUpdateProgress();
+  bool CheckpointUpdateProgress();
+
+  // Update Engine preference store.
+  PrefsInterface* prefs_;
+
   // File descriptor of open device.
   int fd_;
 
   // File descriptor of the kernel device
   int kernel_fd_;
 
   std::string path_;  // Path that fd_ refers to.
   std::string kernel_path_;  // Path that kernel_fd_ refers to.
 
   DeltaArchiveManifest manifest_;
@@ skipping 18 matching lines @@
 
   // Signatures message blob extracted directly from the payload.
   std::vector<char> signatures_message_data_;
 
   DISALLOW_COPY_AND_ASSIGN(DeltaPerformer);
 };
 
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__