net/log/trace_net_log_observer.h

   1 // Copyright 2014 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 NET_LOG_TRACE_NET_LOG_OBSERVER_H_
   6 #define NET_LOG_TRACE_NET_LOG_OBSERVER_H_
   7
   8 #include "base/macros.h"
   9 #include "base/trace_event/trace_event_impl.h"
  10 #include "net/base/net_export.h"
  11 #include "net/log/net_log.h"
  12
  13 namespace net {
  14
  15 // TraceNetLogObserver watches for TraceLog enable, and sends NetLog
  16 // events to TraceLog if it is enabled.
  17 class NET_EXPORT TraceNetLogObserver
  18     : public NetLog::ThreadSafeObserver,
  19       public base::trace_event::TraceLog::EnabledStateObserver {
  20  public:
  21   TraceNetLogObserver();
  22   ~TraceNetLogObserver() override;
  23
  24   // net::NetLog::ThreadSafeObserver implementation:
  25   void OnAddEntry(const NetLog::Entry& entry) override;
  26
  27   // Start to watch for TraceLog enable and disable events.
  28   // This can't be called if already watching for events.
  29   // Watches NetLog only when tracing is enabled.
  30   void WatchForTraceStart(NetLog* net_log);
  31
  32   // Stop watching for TraceLog enable and disable events.
  33   // If WatchForTraceStart is called, this must be called before
  34   // TraceNetLogObserver is destroyed.
  35   void StopWatchForTraceStart();
  36
  37   // base::trace_event::TraceLog::EnabledStateChangedObserver implementation:
  38   void OnTraceLogEnabled() override;
  39   void OnTraceLogDisabled() override;
  40
  41  private:
  42   NetLog* net_log_to_watch_;
  43
  44   DISALLOW_COPY_AND_ASSIGN(TraceNetLogObserver);
  45 };
  46
  47 }  // namespace net
  48
  49 #endif  // NET_LOG_TRACE_NET_LOG_OBSERVER_H_