components/feedback/tracing_manager.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 COMPONENTS_FEEDBACK_TRACING_MANAGER_H_
   6 #define COMPONENTS_FEEDBACK_TRACING_MANAGER_H_
   7
   8 #include <map>
   9 #include <string>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/memory/weak_ptr.h"
  15
  16 namespace base {
  17
  18 class RefCountedString;
  19 class FilePath;
  20
  21 }
  22 // Callback used for getting the output of a trace.
  23 typedef base::Callback<void(scoped_refptr<base::RefCountedString> trace_data)>
  24     TraceDataCallback;
  25
  26 // This class is used to manage performance metrics that can be attached to
  27 // feedback reports.  This class is a Singleton that is owned by the preference
  28 // system.  It should only be created when it is enabled, and should only be
  29 // accessed elsewhere via Get().
  30 //
  31 // When a performance trace is desired, TracingManager::Get()->RequestTrace()
  32 // should be invoked.  The TracingManager will then start preparing a zipped
  33 // version of the performance data.  That data can then be requested via
  34 // GetTraceData().  When the data is no longer needed, it should be discarded
  35 // via DiscardTraceData().
  36 class TracingManager {
  37  public:
  38   virtual ~TracingManager();
  39
  40   // Create a TracingManager.  Can only be called when none exists.
  41   static scoped_ptr<TracingManager> Create();
  42
  43   // Get the current TracingManager.  Returns NULL if one doesn't exist.
  44   static TracingManager* Get();
  45
  46   // Request a trace ending at the current time.  If a trace is already being
  47   // collected, the id for that trace is returned.
  48   int RequestTrace();
  49
  50   // Get the trace data for |id|.  On success, true is returned, and the data is
  51   // returned via |callback|.  Returns false on failure.
  52   bool GetTraceData(int id, const TraceDataCallback& callback);
  53
  54   // Discard the data for trace |id|.
  55   void DiscardTraceData(int id);
  56
  57  private:
  58   TracingManager();
  59
  60   void StartTracing();
  61   void OnTraceDataCollected(base::RefCountedString* data);
  62
  63   // ID of the trace that is being collected.
  64   int current_trace_id_;
  65
  66   // Mapping of trace ID to trace data.
  67   std::map<int, scoped_refptr<base::RefCountedString> > trace_data_;
  68
  69   // Callback for the current trace request.
  70   TraceDataCallback trace_callback_;
  71
  72   base::WeakPtrFactory<TracingManager> weak_ptr_factory_;
  73
  74   DISALLOW_COPY_AND_ASSIGN(TracingManager);
  75 };
  76
  77 #endif  // COMPONENTS_FEEDBACK_TRACING_MANAGER_H_
  78