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      1 // Copyright 2013 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 CHROME_BROWSER_FEEDBACK_TRACING_MANAGER_H_
      6 #define CHROME_BROWSER_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(const base::FilePath& path);
     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  // CHROME_BROWSER_FEEDBACK_TRACING_MANAGER_H_
     78 
     79