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 13 namespace 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. 24 template <class UniqueT> 25 class DiagnosticErrorDelegate : public ErrorDelegate { 26 public: 27 OnError(int error,Connection * connection,Statement * stmt)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: RecordErrorInHistogram(int error)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