1// Copyright (c) 2010 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#ifndef APP_SQL_DIAGNOSTIC_ERROR_DELEGATE_H_
6#define APP_SQL_DIAGNOSTIC_ERROR_DELEGATE_H_
7#pragma once
8
9#include "app/sql/connection.h"
10#include "base/logging.h"
11#include "base/metrics/histogram.h"
12
13namespace sql {
14
15// This class handles the exceptional sqlite errors that we might encounter
16// if for example the db is corrupted. Right now we just generate a UMA
17// histogram for release and an assert for debug builds.
18//
19// Why is it a template you ask? well, that is a funny story. The histograms
20// need to be singletons that is why they are always static at the function
21// scope, but we cannot use the Singleton class because they are not default
22// constructible. The template parameter makes the compiler to create unique
23// classes that don't share the same static variable.
24template <class UniqueT>
25class DiagnosticErrorDelegate : public ErrorDelegate {
26 public:
27
28  virtual int OnError(int error, Connection* connection,
29                      Statement* stmt) {
30    NOTREACHED() << "sqlite error " << error
31                 << ", errno " << connection->GetLastErrno()
32                 << ": " << connection->GetErrorMessage();
33    RecordErrorInHistogram(error);
34    return error;
35  }
36
37 private:
38  static void RecordErrorInHistogram(int error) {
39    // Trim off the extended error codes.
40    error &= 0xff;
41
42    // The histogram values from sqlite result codes go currently from 1 to
43    // 26 currently but 50 gives them room to grow.
44    UMA_HISTOGRAM_ENUMERATION(UniqueT::name(), error, 50);
45  }
46};
47
48}  // namespace sql
49
50#endif  // APP_SQL_DIAGNOSTIC_ERROR_DELEGATE_H_
51