AU: Speed up full update payload generation by running multiple threads.

delta_diff_generator.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_DIFF_GENERATOR_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_DIFF_GENERATOR_H__
 
 #include <string>
 #include <vector>
 #include "base/basictypes.h"
@@ skipping 176 matching lines @@
   // success.
   static bool AssignTempBlocks(
       Graph* graph,
       const std::string& new_root,
       int data_fd,
       off_t* data_file_size,
       std::vector<Vertex::Index>* op_indexes,
       std::vector<std::vector<Vertex::Index>::size_type>* reverse_op_indexes,
       const std::vector<CutEdgeVertexes>& cuts);
 
-  // Given a new rootfs and kernel (|new_image|, |new_kernel_part|), Reads them
-  // sequentially, creating a full update of chunk_size chunks.  Populates
-  // |graph|, |kernel_ops|, and |final_order|, with data about the update
-  // operations, and writes relevant data to |fd|, updating |data_file_size| as
-  // it does. Only the first |image_size| bytes are read from |new_image|
-  // assuming that this is the actual file system.
-  static bool ReadFullUpdateFromDisk(
-      Graph* graph,
-      const std::string& new_kernel_part,
-      const std::string& new_image,
-      off_t image_size,
-      int fd,
-      off_t* data_file_size,
-      off_t chunk_size,
-      std::vector<DeltaArchiveManifest_InstallOperation>* kernel_ops,
-      std::vector<Vertex::Index>* final_order);
-
   // Returns true if |op| is a no-op operation that doesn't do any useful work
   // (e.g., a move operation that copies blocks onto themselves).
   static bool IsNoopOperation(const DeltaArchiveManifest_InstallOperation& op);
 
   static bool InitializePartitionInfo(bool is_kernel,
                                       const std::string& partition,
                                       PartitionInfo* info);
 
  private:
   // This should never be constructed
   DISALLOW_IMPLICIT_CONSTRUCTORS(DeltaDiffGenerator);
 };
 
 extern const char* const kBsdiffPath;
 extern const char* const kBspatchPath;
 extern const char* const kDeltaMagic;
 
 };  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_DIFF_GENERATOR_H__