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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// A class that watches the syncer and attempts to resolve any conflicts that
// occur.
#ifndef SYNC_ENGINE_CONFLICT_RESOLVER_H_
#define SYNC_ENGINE_CONFLICT_RESOLVER_H_
#include <map>
#include <set>
#include <string>
#include "base/basictypes.h"
#include "base/gtest_prod_util.h"
#include "sync/engine/syncer_types.h"
namespace syncer {
namespace syncable {
class BaseTransaction;
class Id;
class MutableEntry;
class WriteTransaction;
} // namespace syncable
class Cryptographer;
namespace sessions {
class ConflictProgress;
class StatusController;
} // namespace sessions
class ConflictResolver {
friend class SyncerTest;
FRIEND_TEST_ALL_PREFIXES(SyncerTest,
ConflictResolverMergeOverwritesLocalEntry);
public:
// Enumeration of different conflict resolutions. Used for histogramming.
enum SimpleConflictResolutions {
OVERWRITE_LOCAL, // Resolved by overwriting local changes.
OVERWRITE_SERVER, // Resolved by overwriting server changes.
UNDELETE, // Resolved by undeleting local item.
IGNORE_ENCRYPTION, // Resolved by ignoring an encryption-only server
// change.
NIGORI_MERGE, // Resolved by merging nigori nodes.
CHANGES_MATCH, // Resolved by ignoring both local and server
// changes because they matched.
CONFLICT_RESOLUTION_SIZE,
};
ConflictResolver();
~ConflictResolver();
// Called by the syncer at the end of a update/commit cycle.
// Returns true if the syncer should try to apply its updates again.
bool ResolveConflicts(syncable::WriteTransaction* trans,
const Cryptographer* cryptographer,
const sessions::ConflictProgress& progress,
sessions::StatusController* status);
private:
enum ProcessSimpleConflictResult {
NO_SYNC_PROGRESS, // No changes to advance syncing made.
SYNC_PROGRESS, // Progress made.
};
ProcessSimpleConflictResult ProcessSimpleConflict(
syncable::WriteTransaction* trans,
const syncable::Id& id,
const Cryptographer* cryptographer,
sessions::StatusController* status);
bool ResolveSimpleConflicts(syncable::WriteTransaction* trans,
const Cryptographer* cryptographer,
const sessions::ConflictProgress& progress,
sessions::StatusController* status);
DISALLOW_COPY_AND_ASSIGN(ConflictResolver);
};
} // namespace syncer
#endif // SYNC_ENGINE_CONFLICT_RESOLVER_H_