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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 // This will mark the trace event as disabled by default. The user will need
22 // to explicitly enable the event.
23 #define TRACE_DISABLED_BY_DEFAULT(name) "disabled-by-default-" name
24 
25 class SK_API SkEventTracer {
26 public:
27 
28     typedef uint64_t Handle;
29 
30     /**
31      * If this is the first call to SetInstance or GetInstance then the passed instance is
32      * installed and true is returned. Otherwise, false is returned. In either case ownership of the
33      * tracer is transferred and it will be deleted when no longer needed.
34      */
35     static bool SetInstance(SkEventTracer*);
36 
37     /**
38      * Gets the event tracer. If this is the first call to SetInstance or GetIntance then a default
39      * event tracer is installed and returned.
40      */
41     static SkEventTracer* GetInstance();
42 
~SkEventTracer()43     virtual ~SkEventTracer() { }
44 
45     // The pointer returned from GetCategoryGroupEnabled() points to a
46     // value with zero or more of the following bits. Used in this class only.
47     // The TRACE_EVENT macros should only use the value as a bool.
48     // These values must be in sync with macro values in trace_event.h in chromium.
49     enum CategoryGroupEnabledFlags {
50         // Category group enabled for the recording mode.
51         kEnabledForRecording_CategoryGroupEnabledFlags = 1 << 0,
52         // Category group enabled for the monitoring mode.
53         kEnabledForMonitoring_CategoryGroupEnabledFlags = 1 << 1,
54         // Category group enabled by SetEventCallbackEnabled().
55         kEnabledForEventCallback_CategoryGroupEnabledFlags = 1 << 2,
56     };
57 
58     virtual const uint8_t* getCategoryGroupEnabled(const char* name) = 0;
59     virtual const char* getCategoryGroupName(
60       const uint8_t* categoryEnabledFlag) = 0;
61 
62     virtual SkEventTracer::Handle
63         addTraceEvent(char phase,
64                       const uint8_t* categoryEnabledFlag,
65                       const char* name,
66                       uint64_t id,
67                       int32_t numArgs,
68                       const char** argNames,
69                       const uint8_t* argTypes,
70                       const uint64_t* argValues,
71                       uint8_t flags) = 0;
72 
73     virtual void
74         updateTraceEventDuration(const uint8_t* categoryEnabledFlag,
75                                  const char* name,
76                                  SkEventTracer::Handle handle) = 0;
77 };
78 
79 #endif // SkEventTracer_DEFINED
80