Add a DeleteKey() method to delete a key from the meta table. This will be used in the TemplateURL…

sql/meta_table.cc

 // 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"
@@ skipping 14 matching lines @@
 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)"))
+        "(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;
 }
 
+void MetaTable::SetVersionNumber(int version) {
+  SetValue(kVersionKey, version);
+}
+
+int MetaTable::GetVersionNumber() {
+  int version = 0;
+  return GetValue(kVersionKey, &version) ? version : 0;
+}
+
+void MetaTable::SetCompatibleVersionNumber(int version) {
+  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::SetValue(const char* key, int value) {
-  Statement s;
-  PrepareSetStatement(&s, key);
-  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;
-  PrepareSetStatement(&s, key);
-  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::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);
-  if (!statement->Step())
-    return false;
-  return true;
+  return statement->Step();
 }
 
 }  // namespace sql