sql/meta_table.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "sql/meta_table.h"
   6
   7 #include "base/logging.h"
   8 #include "base/string_util.h"
   9 #include "sql/connection.h"
  10 #include "sql/statement.h"
  11
  12 namespace sql {
  13
  14 // Key used in our meta table for version numbers.
  15 static const char kVersionKey[] = "version";
  16 static const char kCompatibleVersionKey[] = "last_compatible_version";
  17
  18 MetaTable::MetaTable() : db_(NULL) {
  19 }
  20
  21 MetaTable::~MetaTable() {
  22 }
  23
  24 // static
  25 bool MetaTable::DoesTableExist(sql::Connection* db) {
  26   DCHECK(db);
  27   return db->DoesTableExist("meta");
  28 }
  29
  30 bool MetaTable::Init(Connection* db, int version, int compatible_version) {
  31   DCHECK(!db_ && db);
  32   db_ = db;
  33   if (!DoesTableExist(db)) {
  34     if (!db_->Execute("CREATE TABLE meta"
  35         "(key LONGVARCHAR NOT NULL UNIQUE PRIMARY KEY,"
  36          "value LONGVARCHAR)"))
  37       return false;
  38
  39     // Note: there is no index over the meta table. We currently only have a
  40     // couple of keys, so it doesn't matter. If we start storing more stuff in
  41     // there, we should create an index.
  42     SetVersionNumber(version);
  43     SetCompatibleVersionNumber(compatible_version);
  44   }
  45   return true;
  46 }
  47
  48 void MetaTable::Reset() {
  49   db_ = NULL;
  50 }
  51
  52 bool MetaTable::SetValue(const char* key, const std::string& value) {
  53   Statement s;
  54   if (!PrepareSetStatement(&s, key))
  55     return false;
  56   s.BindString(1, value);
  57   return s.Run();
  58 }
  59
  60 bool MetaTable::GetValue(const char* key, std::string* value) {
  61   Statement s;
  62   if (!PrepareGetStatement(&s, key))
  63     return false;
  64
  65   *value = s.ColumnString(0);
  66   return true;
  67 }
  68
  69 bool MetaTable::SetValue(const char* key, int value) {
  70   Statement s;
  71   if (!PrepareSetStatement(&s, key))
  72     return false;
  73
  74   s.BindInt(1, value);
  75   return s.Run();
  76 }
  77
  78 bool MetaTable::GetValue(const char* key, int* value) {
  79   Statement s;
  80   if (!PrepareGetStatement(&s, key))
  81     return false;
  82
  83   *value = s.ColumnInt(0);
  84   return true;
  85 }
  86
  87 bool MetaTable::SetValue(const char* key, int64 value) {
  88   Statement s;
  89   if (!PrepareSetStatement(&s, key))
  90     return false;
  91   s.BindInt64(1, value);
  92   return s.Run();
  93 }
  94
  95 bool MetaTable::GetValue(const char* key, int64* value) {
  96   Statement s;
  97   if (!PrepareGetStatement(&s, key))
  98     return false;
  99
 100   *value = s.ColumnInt64(0);
 101   return true;
 102 }
 103
 104 void MetaTable::SetVersionNumber(int version) {
 105   SetValue(kVersionKey, version);
 106 }
 107
 108 int MetaTable::GetVersionNumber() {
 109   int version = 0;
 110   if (!GetValue(kVersionKey, &version))
 111     return 0;
 112   return version;
 113 }
 114
 115 void MetaTable::SetCompatibleVersionNumber(int version) {
 116   SetValue(kCompatibleVersionKey, version);
 117 }
 118
 119 int MetaTable::GetCompatibleVersionNumber() {
 120   int version = 0;
 121   if (!GetValue(kCompatibleVersionKey, &version))
 122     return 0;
 123   return version;
 124 }
 125
 126 bool MetaTable::PrepareSetStatement(Statement* statement, const char* key) {
 127   DCHECK(db_ && statement);
 128   statement->Assign(db_->GetCachedStatement(SQL_FROM_HERE,
 129       "INSERT OR REPLACE INTO meta (key,value) VALUES (?,?)"));
 130   if (!statement->is_valid()) {
 131     NOTREACHED() << db_->GetErrorMessage();
 132     return false;
 133   }
 134   statement->BindCString(0, key);
 135   return true;
 136 }
 137
 138 bool MetaTable::PrepareGetStatement(Statement* statement, const char* key) {
 139   DCHECK(db_ && statement);
 140   statement->Assign(db_->GetCachedStatement(SQL_FROM_HERE,
 141       "SELECT value FROM meta WHERE key=?"));
 142   if (!statement->is_valid()) {
 143     NOTREACHED() << db_->GetErrorMessage();
 144     return false;
 145   }
 146   statement->BindCString(0, key);
 147   if (!statement->Step())
 148     return false;
 149   return true;
 150 }
 151
 152 }  // namespace sql