blob: bcc66f5233f790a4e99c32c74cb3a979cac45528 [file] [log] [blame]
// 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.
#ifndef SYNC_SYNCABLE_SYNCABLE_ID_H_
#define SYNC_SYNCABLE_SYNCABLE_ID_H_
#pragma once
#include <iosfwd>
#include <limits>
#include <sstream>
#include <string>
#include "base/hash_tables.h"
class MockConnectionManager;
namespace base {
class StringValue;
}
namespace sql {
class Statement;
}
namespace syncable {
struct EntryKernel;
class Id;
}
namespace syncable {
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:
// This constructor will be handy even when we move away from int64s, just
// for unit tests.
inline Id() : s_("r") { }
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 s_[0] == 's' || s_ == "r";
}
// TODO(sync): We could use null here, but to ease conversion we use "r".
// fix this, this is madness :)
inline bool IsNull() const {
return IsRoot();
}
inline void Clear() {
s_ = "r";
}
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();
private:
friend EntryKernel* UnpackEntry(sql::Statement* statement);
friend void BindFields(const EntryKernel& entry,
sql::Statement* statement);
friend std::ostream& operator<<(std::ostream& out, const Id& id);
friend class MockConnectionManager;
friend class SyncableIdTest;
std::string s_;
};
Id GetNullId();
} // namespace syncable
#endif // SYNC_SYNCABLE_SYNCABLE_ID_H_