Add a DeleteKey() method to delete a key from the meta table. This wi…

…ll be used in the TemplateURL refactoring changes.

Reorder function definitions to match declaration order.  Shorten a few bits.

BUG=none
TEST=none
Review URL: https://chromiumcodereview.appspot.com/9584031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124823 0039d316-1c4b-4281-b951-d872f2087c98

sql/meta_table.cc

@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -32,8 +32,7 @@ bool MetaTable::Init(Connection* db, int version, int compatible_version) {
   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
@@ -49,43 +48,61 @@ 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::GetValue(const char* key, std::string* value) {
+bool MetaTable::SetValue(const char* key, int value) {
   Statement s;
-  if (!PrepareGetStatement(&s, key))
-    return false;
-
-  *value = s.ColumnString(0);
-  return true;
+  PrepareSetStatement(&s, key);
+  s.BindInt(1, value);
+  return s.Run();
 }
 
-bool MetaTable::SetValue(const char* key, int value) {
+bool MetaTable::SetValue(const char* key, int64 value) {
   Statement s;
   PrepareSetStatement(&s, key);
-  s.BindInt(1, value);
+  s.BindInt64(1, value);
   return s.Run();
 }
 
-bool MetaTable::GetValue(const char* key, int* value) {
+bool MetaTable::GetValue(const char* key, std::string* value) {
   Statement s;
   if (!PrepareGetStatement(&s, key))
     return false;
 
-  *value = s.ColumnInt(0);
+  *value = s.ColumnString(0);
   return true;
 }
 
-bool MetaTable::SetValue(const char* key, int64 value) {
+bool MetaTable::GetValue(const char* key, int* value) {
   Statement s;
-  PrepareSetStatement(&s, key);
-  s.BindInt64(1, value);
-  return s.Run();
+  if (!PrepareGetStatement(&s, key))
+    return false;
+
+  *value = s.ColumnInt(0);
+  return true;
 }
 
 bool MetaTable::GetValue(const char* key, int64* value) {
@@ -97,26 +114,11 @@ bool MetaTable::GetValue(const char* key, int64* value) {
   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) {
@@ -131,9 +133,7 @@ bool MetaTable::PrepareGetStatement(Statement* statement, const char* key) {
   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

sql/meta_table.h

@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -68,6 +68,9 @@ class SQL_EXPORT MetaTable {
   bool GetValue(const char* key, int* value);
   bool GetValue(const char* key, int64* value);
 
+  // Deletes the key from the table.
+  bool DeleteKey(const char* key);
+
  private:
   // Conveniences to prepare the two types of statements used by
   // MetaTableHelper.