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// Copyright 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.
#ifndef COMPONENTS_SYNC_SYNCABLE_SYNCABLE_ID_H_
#define COMPONENTS_SYNC_SYNCABLE_SYNCABLE_ID_H_
#include <iosfwd>
#include <limits>
#include <memory>
#include <sstream>
#include <string>
#include "base/containers/hash_tables.h"
#include "base/trace_event/memory_usage_estimator.h"
namespace base {
class StringValue;
} // namespace base
namespace sql {
class Statement;
} // namespace sql
namespace syncer {
namespace syncable {
class Id;
struct EntryKernel;
std::ostream& operator<<(std::ostream& out, const Id& id);
// For historical reasons, 3 concepts got everloaded into the Id:
// 1. A unique, opaque identifier for the object.
// 2. Flag specifing whether server know about this object.
// 3. Flag for root.
//
// We originally wrapped an integer for this information, but now we use a
// string. It will have one of three forms:
// 1. c<client only opaque id> for client items that have not been committed.
// 2. r for the root item.
// 3. s<server provided opaque id> for items that the server knows about.
class Id {
public:
inline Id() {}
inline Id(const Id& that) { Copy(that); }
inline Id& operator=(const Id& that) {
Copy(that);
return *this;
}
inline void Copy(const Id& that) { this->s_ = that.s_; }
inline bool IsRoot() const { return "r" == s_; }
inline bool ServerKnows() const {
return !IsNull() && (s_[0] == 's' || s_ == "r");
}
inline bool IsNull() const { return s_.empty(); }
inline void Clear() { s_.clear(); }
inline int compare(const Id& that) const { return s_.compare(that.s_); }
inline bool operator==(const Id& that) const { return s_ == that.s_; }
inline bool operator!=(const Id& that) const { return s_ != that.s_; }
inline bool operator<(const Id& that) const { return s_ < that.s_; }
inline bool operator>(const Id& that) const { return s_ > that.s_; }
const std::string& value() const { return s_; }
// Return the next highest ID in the lexicographic ordering. This is
// useful for computing upper bounds on std::sets that are ordered
// by operator<.
Id GetLexicographicSuccessor() const;
// Dumps the ID as a value and returns it. Transfers ownership of
// the StringValue to the caller.
base::StringValue* ToValue() const;
// Three functions are used to work with our proto buffers.
std::string GetServerId() const;
static Id CreateFromServerId(const std::string& server_id);
// This should only be used if you get back a reference to a local
// id from the server. Returns a client only opaque id.
static Id CreateFromClientString(const std::string& local_id);
// This method returns an ID that will compare less than any valid ID.
// The returned ID is not a valid ID itself. This is useful for
// computing lower bounds on std::sets that are ordered by operator<.
static Id GetLeastIdForLexicographicComparison();
// Gets root ID.
static Id GetRoot();
private:
friend std::unique_ptr<EntryKernel> UnpackEntry(sql::Statement* statement,
int* total_created_entries);
friend void BindFields(const EntryKernel& entry, sql::Statement* statement);
friend std::ostream& operator<<(std::ostream& out, const Id& id);
friend class SyncableIdTest;
std::string s_;
};
inline size_t EstimateMemoryUsage(const Id& id) {
return base::trace_event::EstimateMemoryUsage(id.value());
}
} // namespace syncable
} // namespace syncer
#endif // COMPONENTS_SYNC_SYNCABLE_SYNCABLE_ID_H_
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