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      1 /*
      2  * Copyright (C) 2014 Google Inc. All rights reserved.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkEventTracer_DEFINED
      9 #define SkEventTracer_DEFINED
     10 
     11 // The class in this header defines the interface between Skia's internal
     12 // tracing macros and an external entity (e.g., Chrome) that will consume them.
     13 // Such an entity should subclass SkEventTracer and provide an instance of
     14 // that event to SkEventTracer::SetInstance.
     15 
     16 // If you're looking for the tracing macros to instrument Skia itself, those
     17 // live in src/core/SkTraceEvent.h
     18 
     19 #include "SkTypes.h"
     20 
     21 class SK_API SkEventTracer {
     22 public:
     23 
     24     typedef uint64_t Handle;
     25 
     26     /**
     27      * If this is the first call to SetInstance or GetInstance then the passed instance is
     28      * installed and true is returned. Otherwise, false is returned. In either case ownership of the
     29      * tracer is transferred and it will be deleted when no longer needed.
     30      */
     31     static bool SetInstance(SkEventTracer*);
     32 
     33     /**
     34      * Gets the event tracer. If this is the first call to SetInstance or GetIntance then a default
     35      * event tracer is installed and returned.
     36      */
     37     static SkEventTracer* GetInstance();
     38 
     39     virtual ~SkEventTracer() { }
     40 
     41     // The pointer returned from GetCategoryGroupEnabled() points to a
     42     // value with zero or more of the following bits. Used in this class only.
     43     // The TRACE_EVENT macros should only use the value as a bool.
     44     // These values must be in sync with macro values in trace_event.h in chromium.
     45     enum CategoryGroupEnabledFlags {
     46         // Category group enabled for the recording mode.
     47         kEnabledForRecording_CategoryGroupEnabledFlags = 1 << 0,
     48         // Category group enabled for the monitoring mode.
     49         kEnabledForMonitoring_CategoryGroupEnabledFlags = 1 << 1,
     50         // Category group enabled by SetEventCallbackEnabled().
     51         kEnabledForEventCallback_CategoryGroupEnabledFlags = 1 << 2,
     52     };
     53 
     54     virtual const uint8_t* getCategoryGroupEnabled(const char* name) = 0;
     55     virtual const char* getCategoryGroupName(const uint8_t* categoryEnabledFlag) = 0;
     56 
     57     virtual SkEventTracer::Handle
     58         addTraceEvent(char phase,
     59                       const uint8_t* categoryEnabledFlag,
     60                       const char* name,
     61                       uint64_t id,
     62                       int32_t numArgs,
     63                       const char** argNames,
     64                       const uint8_t* argTypes,
     65                       const uint64_t* argValues,
     66                       uint8_t flags) = 0;
     67 
     68     virtual void
     69         updateTraceEventDuration(const uint8_t* categoryEnabledFlag,
     70                                  const char* name,
     71                                  SkEventTracer::Handle handle) = 0;
     72 };
     73 
     74 #endif // SkEventTracer_DEFINED
     75