components/proximity_auth/logging/logging.h

   1 // Copyright 2015 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 COMPONENTS_PROXIMITY_AUTH_LOGGING_LOGGING_H
   6 #define COMPONENTS_PROXIMITY_AUTH_LOGGING_LOGGING_H
   7
   8 #include <sstream>
   9
  10 #include "base/logging.h"
  11
  12 namespace proximity_auth {
  13
  14 // Use the PA_LOG() macro for all logging related to Proximity Auth, so the
  15 // system is aware of all logs related to this feature. We display these logs in
  16 // the debug WebUI (chrome://proximity-auth).
  17 //
  18 // PA_LOG() has the same interface as the standard LOG() macro and also creates
  19 // a normal log message of the same severity.
  20 // Examples:
  21 //   PA_LOG(INFO) << "Waiting for " << x << " pending requests.";
  22 //   PA_LOG(ERROR) << "Request failed: " << error_string;
  23 #define PA_LOG(severity)                               \
  24   proximity_auth::ScopedLogMessage(__FILE__, __LINE__, \
  25                                    logging::LOG_##severity).stream()
  26
  27 // Disables all logging while in scope. Intended to be called only from test
  28 // code, to clean up test output.
  29 class ScopedDisableLoggingForTesting {
  30  public:
  31   ScopedDisableLoggingForTesting();
  32   ~ScopedDisableLoggingForTesting();
  33 };
  34
  35 // An intermediate object used by the PA_LOG macro, wrapping a
  36 // logging::LogMessage instance. When this object is destroyed, the message will
  37 // be logged with the standard logging system and also added to Proximity Auth
  38 // specific log buffer.  You should use the PA_LOG() macro instead of this class
  39 // directly.
  40 class ScopedLogMessage {
  41  public:
  42   ScopedLogMessage(const char* file, int line, logging::LogSeverity severity);
  43   ~ScopedLogMessage();
  44
  45   std::ostream& stream() { return stream_; }
  46
  47  private:
  48   const char* file_;
  49   int line_;
  50   logging::LogSeverity severity_;
  51   std::ostringstream stream_;
  52
  53   DISALLOW_COPY_AND_ASSIGN(ScopedLogMessage);
  54 };
  55
  56 }  // namespace proximity_auth
  57
  58 #endif  // COMPONENTS_PROXIMITY_AUTH_LOGGING_LOGGING_H