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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.
#include "sql/meta_table.h"
#include "base/logging.h"
#include "base/string_util.h"
#include "sql/connection.h"
#include "sql/statement.h"
#include "sql/transaction.h"
namespace sql {
// Key used in our meta table for version numbers.
static const char kVersionKey[] = "version";
static const char kCompatibleVersionKey[] = "last_compatible_version";
MetaTable::MetaTable() : db_(NULL) {
}
MetaTable::~MetaTable() {
}
// static
bool MetaTable::DoesTableExist(sql::Connection* db) {
DCHECK(db);
return db->DoesTableExist("meta");
}
bool MetaTable::Init(Connection* db, int version, int compatible_version) {
DCHECK(!db_ && db);
db_ = db;
// If values stored are null or missing entirely, 0 will be reported.
// Require new clients to start with a greater initial version.
DCHECK_GT(version, 0);
DCHECK_GT(compatible_version, 0);
// Make sure the table is created an populated atomically.
sql::Transaction transaction(db_);
if (!transaction.Begin())
return false;
if (!DoesTableExist(db)) {
if (!db_->Execute("CREATE TABLE meta"
"(key LONGVARCHAR NOT NULL UNIQUE PRIMARY KEY, value LONGVARCHAR)"))
return false;
// Note: there is no index over the meta table. We currently only have a
// couple of keys, so it doesn't matter. If we start storing more stuff in
// there, we should create an index.
SetVersionNumber(version);
SetCompatibleVersionNumber(compatible_version);
}
return transaction.Commit();
}
void MetaTable::Reset() {
db_ = NULL;
}
void MetaTable::SetVersionNumber(int version) {
DCHECK_GT(version, 0);
SetValue(kVersionKey, version);
}
int MetaTable::GetVersionNumber() {
int version = 0;
return GetValue(kVersionKey, &version) ? version : 0;
}
void MetaTable::SetCompatibleVersionNumber(int version) {
DCHECK_GT(version, 0);
SetValue(kCompatibleVersionKey, version);
}
int MetaTable::GetCompatibleVersionNumber() {
int version = 0;
return GetValue(kCompatibleVersionKey, &version) ? version : 0;
}
bool MetaTable::SetValue(const char* key, const std::string& value) {
Statement s;
PrepareSetStatement(&s, key);
s.BindString(1, value);
return s.Run();
}
bool MetaTable::SetValue(const char* key, int value) {
Statement s;
PrepareSetStatement(&s, key);
s.BindInt(1, value);
return s.Run();
}
bool MetaTable::SetValue(const char* key, int64 value) {
Statement s;
PrepareSetStatement(&s, key);
s.BindInt64(1, value);
return s.Run();
}
bool MetaTable::GetValue(const char* key, std::string* value) {
Statement s;
if (!PrepareGetStatement(&s, key))
return false;
*value = s.ColumnString(0);
return true;
}
bool MetaTable::GetValue(const char* key, int* value) {
Statement s;
if (!PrepareGetStatement(&s, key))
return false;
*value = s.ColumnInt(0);
return true;
}
bool MetaTable::GetValue(const char* key, int64* value) {
Statement s;
if (!PrepareGetStatement(&s, key))
return false;
*value = s.ColumnInt64(0);
return true;
}
bool MetaTable::DeleteKey(const char* key) {
DCHECK(db_);
Statement s(db_->GetUniqueStatement("DELETE FROM meta WHERE key=?"));
s.BindCString(0, key);
return s.Run();
}
void MetaTable::PrepareSetStatement(Statement* statement, const char* key) {
DCHECK(db_ && statement);
statement->Assign(db_->GetCachedStatement(SQL_FROM_HERE,
"INSERT OR REPLACE INTO meta (key,value) VALUES (?,?)"));
statement->BindCString(0, key);
}
bool MetaTable::PrepareGetStatement(Statement* statement, const char* key) {
DCHECK(db_ && statement);
statement->Assign(db_->GetCachedStatement(SQL_FROM_HERE,
"SELECT value FROM meta WHERE key=?"));
statement->BindCString(0, key);
return statement->Step();
}
} // namespace sql
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