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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_SYNC_BASE_SYNC_INVALIDATION_H_
#define COMPONENTS_SYNC_BASE_SYNC_INVALIDATION_H_
#include <stdint.h>
#include <string>
namespace syncer {
// An interface that wraps sync's interactions with the component that provides
// it with invalidations.
class SyncInvalidation {
public:
// Orders invalidations based on version number and IsUnknownVersion().
static bool LessThanByVersion(const SyncInvalidation& a,
const SyncInvalidation& b);
SyncInvalidation();
virtual ~SyncInvalidation();
// Returns true if this is an 'unknown version' invalidation.
// Such invalidations have no valid payload or version number.
virtual bool IsUnknownVersion() const = 0;
// Returns the payload of this item.
virtual const std::string& GetPayload() const = 0;
// Returns the version of this item.
// DCHECKs if this is an unknown version invalidation.
//
// It is preferable to use the LessThan() function, which handles unknown
// versions properly, rather than this function.
virtual int64_t GetVersion() const = 0;
// This function will be called when the invalidation has been handled
// successfully.
virtual void Acknowledge() = 0;
// This function should be called if a lack of buffer space required that we
// drop this invalidation.
//
// To indicate recovery from a drop event, the receiver of this invalidation
// will call Acknowledge() on the most recently dropped invalidation.
virtual void Drop() = 0;
};
} // namespace syncer
#endif // COMPONENTS_SYNC_BASE_SYNC_INVALIDATION_H_
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