1 files changed, 152 insertions, 0 deletions
diff --git a/sql/meta_table.cc b/sql/meta_table.cc
new file mode 100644
index 0000000..c4736ef
--- /dev/null
+++ b/sql/meta_table.cc
@@ -0,0 +1,152 @@
+// Copyright (c) 2011 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"
+
+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 (!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 true;
+}
+
+void MetaTable::Reset() {
+  db_ = NULL;
+}
+
+bool MetaTable::SetValue(const char* key, const std::string& value) {
+  Statement s;
+  if (!PrepareSetStatement(&s, key))
+    return false;
+  s.BindString(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::SetValue(const char* key, int value) {
+  Statement s;
+  if (!PrepareSetStatement(&s, key))
+    return false;
+
+  s.BindInt(1, value);
+  return s.Run();
+}
+
+bool MetaTable::GetValue(const char* key, int* value) {
+  Statement s;
+  if (!PrepareGetStatement(&s, key))
+    return false;
+
+  *value = s.ColumnInt(0);
+  return true;
+}
+
+bool MetaTable::SetValue(const char* key, int64 value) {
+  Statement s;
+  if (!PrepareSetStatement(&s, key))
+    return false;
+  s.BindInt64(1, value);
+  return s.Run();
+}
+
+bool MetaTable::GetValue(const char* key, int64* value) {
+  Statement s;
+  if (!PrepareGetStatement(&s, key))
+    return false;
+
+  *value = s.ColumnInt64(0);
+  return true;
+}
+
+void MetaTable::SetVersionNumber(int version) {
+  SetValue(kVersionKey, version);
+}
+
+int MetaTable::GetVersionNumber() {
+  int version = 0;
+  if (!GetValue(kVersionKey, &version))
+    return 0;
+  return version;
+}
+
+void MetaTable::SetCompatibleVersionNumber(int version) {
+  SetValue(kCompatibleVersionKey, version);
+}
+
+int MetaTable::GetCompatibleVersionNumber() {
+  int version = 0;
+  if (!GetValue(kCompatibleVersionKey, &version))
+    return 0;
+  return version;
+}
+
+bool 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 (?,?)"));
+  if (!statement->is_valid()) {
+    NOTREACHED() << db_->GetErrorMessage();
+    return false;
+  }
+  statement->BindCString(0, key);
+  return true;
+}
+
+bool MetaTable::PrepareGetStatement(Statement* statement, const char* key) {
+  DCHECK(db_ && statement);
+  statement->Assign(db_->GetCachedStatement(SQL_FROM_HERE,
+      "SELECT value FROM meta WHERE key=?"));
+  if (!statement->is_valid()) {
+    NOTREACHED() << db_->GetErrorMessage();
+    return false;
+  }
+  statement->BindCString(0, key);
+  if (!statement->Step())
+    return false;
+  return true;
+}
+
+}  // namespace sql