Move app/sql/* files to sql/ directory.

I can't remove app/app.gyp and app/app_base.gypi yet because they are referenced
by third_party gyp files :(

BUG=72317
TEST=None

R=rsesek@chromium.org

move app/sql to sql

Review URL: http://codereview.chromium.org/7353026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@93069 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 83 insertions, 0 deletions

diff --git a/sql/meta_table.h b/sql/meta_table.h
new file mode 100644
index 0000000..4a640d8
--- /dev/null
+++ b/sql/meta_table.h
@@ -0,0 +1,83 @@
+// 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.
+
+#ifndef SQL_META_TABLE_H_
+#define SQL_META_TABLE_H_
+#pragma once
+
+#include <string>
+
+#include "base/basictypes.h"
+
+namespace sql {
+
+class Connection;
+class Statement;
+
+class MetaTable {
+ public:
+  MetaTable();
+  ~MetaTable();
+
+  // Returns true if the 'meta' table exists.
+  static bool DoesTableExist(Connection* db);
+
+  // Initializes the MetaTableHelper, creating the meta table if necessary. For
+  // new tables, it will initialize the version number to |version| and the
+  // compatible version number to |compatible_version|.
+  bool Init(Connection* db, int version, int compatible_version);
+
+  // Resets this MetaTable object, making another call to Init() possible.
+  void Reset();
+
+  // The version number of the database. This should be the version number of
+  // the creator of the file. The version number will be 0 if there is no
+  // previously set version number.
+  //
+  // See also Get/SetCompatibleVersionNumber().
+  void SetVersionNumber(int version);
+  int GetVersionNumber();
+
+  // The compatible version number is the lowest version of the code that this
+  // database can be read by. If there are minor changes or additions, old
+  // versions of the code can still work with the database without failing.
+  //
+  // For example, if an optional column is added to a table in version 3, the
+  // new code will set the version to 3, and the compatible version to 2, since
+  // the code expecting version 2 databases can still read and write the table.
+  //
+  // Rule of thumb: check the version number when you're upgrading, but check
+  // the compatible version number to see if you can read the file at all. If
+  // it's larger than you code is expecting, fail.
+  //
+  // The compatible version number will be 0 if there is no previously set
+  // compatible version number.
+  void SetCompatibleVersionNumber(int version);
+  int GetCompatibleVersionNumber();
+
+  // Set the given arbitrary key with the given data. Returns true on success.
+  bool SetValue(const char* key, const std::string& value);
+  bool SetValue(const char* key, int value);
+  bool SetValue(const char* key, int64 value);
+
+  // Retrieves the value associated with the given key. This will use sqlite's
+  // type conversion rules. It will return true on success.
+  bool GetValue(const char* key, std::string* value);
+  bool GetValue(const char* key, int* value);
+  bool GetValue(const char* key, int64* value);
+
+ private:
+  // Conveniences to prepare the two types of statements used by
+  // MetaTableHelper.
+  bool PrepareSetStatement(Statement* statement, const char* key);
+  bool PrepareGetStatement(Statement* statement, const char* key);
+
+  Connection* db_;
+
+  DISALLOW_COPY_AND_ASSIGN(MetaTable);
+};
+
+}  // namespace sql
+
+#endif  // SQL_META_TABLE_H_