sync/engine/build_commit_command.h

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