sync/engine/build_commit_command.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef SYNC_ENGINE_BUILD_COMMIT_COMMAND_H_
   6 #define SYNC_ENGINE_BUILD_COMMIT_COMMAND_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/compiler_specific.h"
  10 #include "base/gtest_prod_util.h"
  11 #include "sync/engine/syncer_command.h"
  12 #include "sync/syncable/entry_kernel.h"
  13
  14 namespace syncer {
  15
  16 namespace sessions {
  17 class OrderedCommitSet;
  18 }
  19
  20 namespace syncable {
  21 class Entry;
  22 }
  23
  24 // A class that contains the code used to serialize a set of sync items into a
  25 // protobuf commit message.  This conversion process references the
  26 // syncable::Directory, which is why it must be called within the same
  27 // transaction as the GetCommitIdsCommand that fetched the set of items to be
  28 // committed.
  29 //
  30 // See SyncerCommand documentation for more info.
  31 class BuildCommitCommand : public SyncerCommand {
  32  public:
  33   // The batch_commit_set parameter contains a set of references to the items
  34   // that should be committed.
  35   //
  36   // The commit_message parameter is an output parameter which will contain the
  37   // fully initialized commit message once ExecuteImpl() has been called.
  38   BuildCommitCommand(const sessions::OrderedCommitSet& batch_commit_set,
  39                      sync_pb::ClientToServerMessage* commit_message);
  40   virtual ~BuildCommitCommand();
  41
  42   // SyncerCommand implementation.
  43   virtual SyncerError ExecuteImpl(sessions::SyncSession* session) OVERRIDE;
  44
  45  private:
  46   FRIEND_TEST_ALL_PREFIXES(BuildCommitCommandTest, InterpolatePosition);
  47
  48   // Functions returning constants controlling range of values.
  49   static int64 GetFirstPosition();
  50   static int64 GetLastPosition();
  51   static int64 GetGap();
  52
  53   void AddExtensionsActivityToMessage(sessions::SyncSession* session,
  54                                       sync_pb::CommitMessage* message);
  55   // Helper for computing position.  Find the numeric position value
  56   // of the closest already-synced entry.  |direction| must be one of
  57   // NEXT_ID or PREV_ID; this parameter controls the search direction.
  58   // For an open range (no predecessor or successor), the return
  59   // value will be kFirstPosition or kLastPosition.
  60   int64 FindAnchorPosition(syncable::IdField direction,
  61                            const syncable::Entry& entry);
  62   // Given two values of the type returned by FindAnchorPosition,
  63   // compute a third value in between the two ranges.
  64   int64 InterpolatePosition(int64 lo, int64 hi);
  65
  66   DISALLOW_COPY_AND_ASSIGN(BuildCommitCommand);
  67
  68   // Input parameter; see constructor comment.
  69   const sessions::OrderedCommitSet& batch_commit_set_;
  70
  71   // Output parameter; see constructor comment.
  72   sync_pb::ClientToServerMessage* commit_message_;
  73 };
  74
  75 }  // namespace syncer
  76
  77 #endif  // SYNC_ENGINE_BUILD_COMMIT_COMMAND_H_