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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 
79