1 // Copyright (c) 2012 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 BASE_TRACE_EVENT_TRACE_EVENT_H_
6 #define BASE_TRACE_EVENT_TRACE_EVENT_H_
7 
8 // This header file defines implementation details of how the trace macros in
9 // trace_event_common.h collect and store trace events. Anything not
10 // implementation-specific should go in trace_macros_common.h instead of here.
11 
12 #include <stddef.h>
13 #include <stdint.h>
14 
15 #include <string>
16 
17 #include "base/atomicops.h"
18 #include "base/macros.h"
19 #include "base/time/time.h"
20 #include "base/trace_event/common/trace_event_common.h"
21 #include "base/trace_event/trace_event_system_stats_monitor.h"
22 #include "base/trace_event/trace_log.h"
23 #include "build/build_config.h"
24 
25 // By default, const char* argument values are assumed to have long-lived scope
26 // and will not be copied. Use this macro to force a const char* to be copied.
27 #define TRACE_STR_COPY(str) \
28     trace_event_internal::TraceStringWithCopy(str)
29 
30 // By default, uint64_t ID argument values are not mangled with the Process ID
31 // in TRACE_EVENT_ASYNC macros. Use this macro to force Process ID mangling.
32 #define TRACE_ID_MANGLE(id) \
33     trace_event_internal::TraceID::ForceMangle(id)
34 
35 // By default, pointers are mangled with the Process ID in TRACE_EVENT_ASYNC
36 // macros. Use this macro to prevent Process ID mangling.
37 #define TRACE_ID_DONT_MANGLE(id) \
38     trace_event_internal::TraceID::DontMangle(id)
39 
40 // Sets the current sample state to the given category and name (both must be
41 // constant strings). These states are intended for a sampling profiler.
42 // Implementation note: we store category and name together because we don't
43 // want the inconsistency/expense of storing two pointers.
44 // |thread_bucket| is [0..2] and is used to statically isolate samples in one
45 // thread from others.
46 #define TRACE_EVENT_SET_SAMPLING_STATE_FOR_BUCKET( \
47     bucket_number, category, name)                 \
48         trace_event_internal::                     \
49         TraceEventSamplingStateScope<bucket_number>::Set(category "\0" name)
50 
51 // Returns a current sampling state of the given bucket.
52 #define TRACE_EVENT_GET_SAMPLING_STATE_FOR_BUCKET(bucket_number) \
53     trace_event_internal::TraceEventSamplingStateScope<bucket_number>::Current()
54 
55 // Creates a scope of a sampling state of the given bucket.
56 //
57 // {  // The sampling state is set within this scope.
58 //    TRACE_EVENT_SAMPLING_STATE_SCOPE_FOR_BUCKET(0, "category", "name");
59 //    ...;
60 // }
61 #define TRACE_EVENT_SCOPED_SAMPLING_STATE_FOR_BUCKET(                   \
62     bucket_number, category, name)                                      \
63     trace_event_internal::TraceEventSamplingStateScope<bucket_number>   \
64         traceEventSamplingScope(category "\0" name);
65 
66 #define TRACE_EVENT_API_CURRENT_THREAD_ID \
67   static_cast<int>(base::PlatformThread::CurrentId())
68 
69 #define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE() \
70   UNLIKELY(*INTERNAL_TRACE_EVENT_UID(category_group_enabled) &           \
71            (base::trace_event::TraceLog::ENABLED_FOR_RECORDING |         \
72             base::trace_event::TraceLog::ENABLED_FOR_EVENT_CALLBACK |    \
73             base::trace_event::TraceLog::ENABLED_FOR_ETW_EXPORT))
74 
75 ////////////////////////////////////////////////////////////////////////////////
76 // Implementation specific tracing API definitions.
77 
78 // Get a pointer to the enabled state of the given trace category. Only
79 // long-lived literal strings should be given as the category group. The
80 // returned pointer can be held permanently in a local static for example. If
81 // the unsigned char is non-zero, tracing is enabled. If tracing is enabled,
82 // TRACE_EVENT_API_ADD_TRACE_EVENT can be called. It's OK if tracing is disabled
83 // between the load of the tracing state and the call to
84 // TRACE_EVENT_API_ADD_TRACE_EVENT, because this flag only provides an early out
85 // for best performance when tracing is disabled.
86 // const unsigned char*
87 //     TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(const char* category_group)
88 #define TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED \
89     base::trace_event::TraceLog::GetCategoryGroupEnabled
90 
91 // Get the number of times traces have been recorded. This is used to implement
92 // the TRACE_EVENT_IS_NEW_TRACE facility.
93 // unsigned int TRACE_EVENT_API_GET_NUM_TRACES_RECORDED()
94 #define TRACE_EVENT_API_GET_NUM_TRACES_RECORDED \
95     base::trace_event::TraceLog::GetInstance()->GetNumTracesRecorded
96 
97 // Add a trace event to the platform tracing system.
98 // base::trace_event::TraceEventHandle TRACE_EVENT_API_ADD_TRACE_EVENT(
99 //                    char phase,
100 //                    const unsigned char* category_group_enabled,
101 //                    const char* name,
102 //                    unsigned long long id,
103 //                    int num_args,
104 //                    const char** arg_names,
105 //                    const unsigned char* arg_types,
106 //                    const unsigned long long* arg_values,
107 //                    const scoped_refptr<ConvertableToTraceFormat>*
108 //                    convertable_values,
109 //                    unsigned int flags)
110 #define TRACE_EVENT_API_ADD_TRACE_EVENT \
111     base::trace_event::TraceLog::GetInstance()->AddTraceEvent
112 
113 // Add a trace event to the platform tracing system.
114 // base::trace_event::TraceEventHandle
115 // TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_BIND_ID(
116 //                    char phase,
117 //                    const unsigned char* category_group_enabled,
118 //                    const char* name,
119 //                    unsigned long long id,
120 //                    unsigned long long bind_id,
121 //                    int num_args,
122 //                    const char** arg_names,
123 //                    const unsigned char* arg_types,
124 //                    const unsigned long long* arg_values,
125 //                    const scoped_refptr<ConvertableToTraceFormat>*
126 //                    convertable_values,
127 //                    unsigned int flags)
128 #define TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_BIND_ID \
129   base::trace_event::TraceLog::GetInstance()->AddTraceEventWithBindId
130 
131 // Add a trace event to the platform tracing system overriding the pid.
132 // The resulting event will have tid = pid == (process_id passed here).
133 // base::trace_event::TraceEventHandle
134 // TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_PROCESS_ID(
135 //                    char phase,
136 //                    const unsigned char* category_group_enabled,
137 //                    const char* name,
138 //                    unsigned long long id,
139 //                    int process_id,
140 //                    int num_args,
141 //                    const char** arg_names,
142 //                    const unsigned char* arg_types,
143 //                    const unsigned long long* arg_values,
144 //                    const scoped_refptr<ConvertableToTraceFormat>*
145 //                    convertable_values,
146 //                    unsigned int flags)
147 #define TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_PROCESS_ID \
148   base::trace_event::TraceLog::GetInstance()->AddTraceEventWithProcessId
149 
150 // Add a trace event to the platform tracing system.
151 // base::trace_event::TraceEventHandle
152 // TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_TIMESTAMP(
153 //                    char phase,
154 //                    const unsigned char* category_group_enabled,
155 //                    const char* name,
156 //                    unsigned long long id,
157 //                    int thread_id,
158 //                    const TimeTicks& timestamp,
159 //                    int num_args,
160 //                    const char** arg_names,
161 //                    const unsigned char* arg_types,
162 //                    const unsigned long long* arg_values,
163 //                    const scoped_refptr<ConvertableToTraceFormat>*
164 //                    convertable_values,
165 //                    unsigned int flags)
166 #define TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP \
167     base::trace_event::TraceLog::GetInstance() \
168       ->AddTraceEventWithThreadIdAndTimestamp
169 
170 // Set the duration field of a COMPLETE trace event.
171 // void TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
172 //     const unsigned char* category_group_enabled,
173 //     const char* name,
174 //     base::trace_event::TraceEventHandle id)
175 #define TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION \
176     base::trace_event::TraceLog::GetInstance()->UpdateTraceEventDuration
177 
178 // Adds a metadata event to the trace log. The |AppendValueAsTraceFormat| method
179 // on the convertable value will be called at flush time.
180 // TRACE_EVENT_API_ADD_METADATA_EVENT(
181 //   const char* event_name,
182 //   const char* arg_name,
183 //   scoped_refptr<ConvertableToTraceFormat> arg_value)
184 #define TRACE_EVENT_API_ADD_METADATA_EVENT \
185     trace_event_internal::AddMetadataEvent
186 
187 // Defines atomic operations used internally by the tracing system.
188 #define TRACE_EVENT_API_ATOMIC_WORD base::subtle::AtomicWord
189 #define TRACE_EVENT_API_ATOMIC_LOAD(var) base::subtle::NoBarrier_Load(&(var))
190 #define TRACE_EVENT_API_ATOMIC_STORE(var, value) \
191     base::subtle::NoBarrier_Store(&(var), (value))
192 
193 // Defines visibility for classes in trace_event.h
194 #define TRACE_EVENT_API_CLASS_EXPORT BASE_EXPORT
195 
196 // The thread buckets for the sampling profiler.
197 TRACE_EVENT_API_CLASS_EXPORT extern \
198     TRACE_EVENT_API_ATOMIC_WORD g_trace_state[3];
199 
200 #define TRACE_EVENT_API_THREAD_BUCKET(thread_bucket)                           \
201     g_trace_state[thread_bucket]
202 
203 ////////////////////////////////////////////////////////////////////////////////
204 
205 // Implementation detail: trace event macros create temporary variables
206 // to keep instrumentation overhead low. These macros give each temporary
207 // variable a unique name based on the line number to prevent name collisions.
208 #define INTERNAL_TRACE_EVENT_UID3(a,b) \
209     trace_event_unique_##a##b
210 #define INTERNAL_TRACE_EVENT_UID2(a,b) \
211     INTERNAL_TRACE_EVENT_UID3(a,b)
212 #define INTERNAL_TRACE_EVENT_UID(name_prefix) \
213     INTERNAL_TRACE_EVENT_UID2(name_prefix, __LINE__)
214 
215 // Implementation detail: internal macro to create static category.
216 // No barriers are needed, because this code is designed to operate safely
217 // even when the unsigned char* points to garbage data (which may be the case
218 // on processors without cache coherency).
219 #define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES( \
220     category_group, atomic, category_group_enabled) \
221     category_group_enabled = \
222         reinterpret_cast<const unsigned char*>(TRACE_EVENT_API_ATOMIC_LOAD( \
223             atomic)); \
224     if (UNLIKELY(!category_group_enabled)) { \
225       category_group_enabled = \
226           TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group); \
227       TRACE_EVENT_API_ATOMIC_STORE(atomic, \
228           reinterpret_cast<TRACE_EVENT_API_ATOMIC_WORD>( \
229               category_group_enabled)); \
230     }
231 
232 #define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group) \
233     static TRACE_EVENT_API_ATOMIC_WORD INTERNAL_TRACE_EVENT_UID(atomic) = 0; \
234     const unsigned char* INTERNAL_TRACE_EVENT_UID(category_group_enabled); \
235     INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES(category_group, \
236         INTERNAL_TRACE_EVENT_UID(atomic), \
237         INTERNAL_TRACE_EVENT_UID(category_group_enabled));
238 
239 // Implementation detail: internal macro to create static category and add
240 // event if the category is enabled.
241 #define INTERNAL_TRACE_EVENT_ADD(phase, category_group, name, flags, ...) \
242     do { \
243       INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
244       if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
245         trace_event_internal::AddTraceEvent( \
246             phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
247             trace_event_internal::kNoId, flags, \
248             trace_event_internal::kNoId, ##__VA_ARGS__); \
249       } \
250     } while (0)
251 
252 // Implementation detail: internal macro to create static category and add begin
253 // event if the category is enabled. Also adds the end event when the scope
254 // ends.
255 #define INTERNAL_TRACE_EVENT_ADD_SCOPED(category_group, name, ...) \
256     INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
257     trace_event_internal::ScopedTracer INTERNAL_TRACE_EVENT_UID(tracer); \
258     if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
259       base::trace_event::TraceEventHandle h = \
260           trace_event_internal::AddTraceEvent( \
261               TRACE_EVENT_PHASE_COMPLETE, \
262               INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
263               trace_event_internal::kNoId, TRACE_EVENT_FLAG_NONE, \
264               trace_event_internal::kNoId, ##__VA_ARGS__); \
265       INTERNAL_TRACE_EVENT_UID(tracer).Initialize( \
266           INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, h); \
267     }
268 
269 #define INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_FLOW( \
270     category_group, name, bind_id, flow_flags, ...) \
271   INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
272   trace_event_internal::ScopedTracer INTERNAL_TRACE_EVENT_UID(tracer); \
273   if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
274     unsigned int trace_event_flags = flow_flags; \
275     trace_event_internal::TraceID trace_event_bind_id(bind_id, \
276                                                       &trace_event_flags); \
277     base::trace_event::TraceEventHandle h = \
278         trace_event_internal::AddTraceEvent( \
279             TRACE_EVENT_PHASE_COMPLETE, \
280             INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
281             trace_event_internal::kNoId, trace_event_flags, \
282             trace_event_bind_id.data(), ##__VA_ARGS__); \
283     INTERNAL_TRACE_EVENT_UID(tracer).Initialize( \
284         INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, h); \
285   }
286 
287 // Implementation detail: internal macro to create static category and add
288 // event if the category is enabled.
289 #define INTERNAL_TRACE_EVENT_ADD_WITH_ID(phase, category_group, name, id, \
290                                          flags, ...) \
291     do { \
292       INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
293       if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
294         unsigned int trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID; \
295         trace_event_internal::TraceID trace_event_trace_id( \
296             id, &trace_event_flags); \
297         trace_event_internal::AddTraceEvent( \
298             phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), \
299             name, trace_event_trace_id.data(), trace_event_flags, \
300             trace_event_internal::kNoId, ##__VA_ARGS__); \
301       } \
302     } while (0)
303 
304 // Implementation detail: internal macro to create static category and add
305 // event if the category is enabled.
306 #define INTERNAL_TRACE_EVENT_ADD_WITH_TIMESTAMP(phase, category_group, name, \
307                                                 timestamp, flags, ...)       \
308   do {                                                                       \
309     INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group);                  \
310     if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) {  \
311       trace_event_internal::AddTraceEventWithThreadIdAndTimestamp(           \
312           phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name,     \
313           trace_event_internal::kNoId, TRACE_EVENT_API_CURRENT_THREAD_ID,    \
314           base::TimeTicks::FromInternalValue(timestamp),                     \
315           flags | TRACE_EVENT_FLAG_EXPLICIT_TIMESTAMP,                       \
316           trace_event_internal::kNoId, ##__VA_ARGS__);                       \
317     }                                                                        \
318   } while (0)
319 
320 // Implementation detail: internal macro to create static category and add
321 // event if the category is enabled.
322 #define INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                   \
323     phase, category_group, name, id, thread_id, timestamp, flags, ...)        \
324   do {                                                                        \
325     INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group);                   \
326     if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) {   \
327       unsigned int trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID;       \
328       trace_event_internal::TraceID trace_event_trace_id(id,                  \
329                                                          &trace_event_flags); \
330       trace_event_internal::AddTraceEventWithThreadIdAndTimestamp(            \
331           phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name,      \
332           trace_event_trace_id.data(), thread_id,                             \
333           base::TimeTicks::FromInternalValue(timestamp),                      \
334           trace_event_flags | TRACE_EVENT_FLAG_EXPLICIT_TIMESTAMP,            \
335           trace_event_internal::kNoId, ##__VA_ARGS__);                        \
336     }                                                                         \
337   } while (0)
338 
339 namespace trace_event_internal {
340 
341 // Specify these values when the corresponding argument of AddTraceEvent is not
342 // used.
343 const int kZeroNumArgs = 0;
344 const unsigned long long kNoId = 0;
345 
346 // TraceID encapsulates an ID that can either be an integer or pointer. Pointers
347 // are by default mangled with the Process ID so that they are unlikely to
348 // collide when the same pointer is used on different processes.
349 class TraceID {
350  public:
351   class DontMangle {
352    public:
DontMangle(const void * id)353     explicit DontMangle(const void* id)
354         : data_(static_cast<unsigned long long>(
355               reinterpret_cast<uintptr_t>(id))) {}
DontMangle(unsigned long long id)356     explicit DontMangle(unsigned long long id) : data_(id) {}
DontMangle(unsigned long id)357     explicit DontMangle(unsigned long id) : data_(id) {}
DontMangle(unsigned int id)358     explicit DontMangle(unsigned int id) : data_(id) {}
DontMangle(unsigned short id)359     explicit DontMangle(unsigned short id) : data_(id) {}
DontMangle(unsigned char id)360     explicit DontMangle(unsigned char id) : data_(id) {}
DontMangle(long long id)361     explicit DontMangle(long long id)
362         : data_(static_cast<unsigned long long>(id)) {}
DontMangle(long id)363     explicit DontMangle(long id)
364         : data_(static_cast<unsigned long long>(id)) {}
DontMangle(int id)365     explicit DontMangle(int id)
366         : data_(static_cast<unsigned long long>(id)) {}
DontMangle(short id)367     explicit DontMangle(short id)
368         : data_(static_cast<unsigned long long>(id)) {}
DontMangle(signed char id)369     explicit DontMangle(signed char id)
370         : data_(static_cast<unsigned long long>(id)) {}
data()371     unsigned long long data() const { return data_; }
372    private:
373     unsigned long long data_;
374   };
375 
376   class ForceMangle {
377    public:
ForceMangle(unsigned long long id)378     explicit ForceMangle(unsigned long long id) : data_(id) {}
ForceMangle(unsigned long id)379     explicit ForceMangle(unsigned long id) : data_(id) {}
ForceMangle(unsigned int id)380     explicit ForceMangle(unsigned int id) : data_(id) {}
ForceMangle(unsigned short id)381     explicit ForceMangle(unsigned short id) : data_(id) {}
ForceMangle(unsigned char id)382     explicit ForceMangle(unsigned char id) : data_(id) {}
ForceMangle(long long id)383     explicit ForceMangle(long long id)
384         : data_(static_cast<unsigned long long>(id)) {}
ForceMangle(long id)385     explicit ForceMangle(long id)
386         : data_(static_cast<unsigned long long>(id)) {}
ForceMangle(int id)387     explicit ForceMangle(int id)
388         : data_(static_cast<unsigned long long>(id)) {}
ForceMangle(short id)389     explicit ForceMangle(short id)
390         : data_(static_cast<unsigned long long>(id)) {}
ForceMangle(signed char id)391     explicit ForceMangle(signed char id)
392         : data_(static_cast<unsigned long long>(id)) {}
data()393     unsigned long long data() const { return data_; }
394    private:
395     unsigned long long data_;
396   };
TraceID(const void * id,unsigned int * flags)397   TraceID(const void* id, unsigned int* flags)
398       : data_(static_cast<unsigned long long>(
399               reinterpret_cast<uintptr_t>(id))) {
400     *flags |= TRACE_EVENT_FLAG_MANGLE_ID;
401   }
TraceID(ForceMangle id,unsigned int * flags)402   TraceID(ForceMangle id, unsigned int* flags) : data_(id.data()) {
403     *flags |= TRACE_EVENT_FLAG_MANGLE_ID;
404   }
TraceID(DontMangle id,unsigned int *)405   TraceID(DontMangle id, unsigned int* /* flags */) : data_(id.data()) {
406   }
TraceID(unsigned long long id,unsigned int * flags)407   TraceID(unsigned long long id, unsigned int* flags)
408       : data_(id) { (void)flags; }
TraceID(unsigned long id,unsigned int * flags)409   TraceID(unsigned long id, unsigned int* flags)
410       : data_(id) { (void)flags; }
TraceID(unsigned int id,unsigned int * flags)411   TraceID(unsigned int id, unsigned int* flags)
412       : data_(id) { (void)flags; }
TraceID(unsigned short id,unsigned int * flags)413   TraceID(unsigned short id, unsigned int* flags)
414       : data_(id) { (void)flags; }
TraceID(unsigned char id,unsigned int * flags)415   TraceID(unsigned char id, unsigned int* flags)
416       : data_(id) { (void)flags; }
TraceID(long long id,unsigned int * flags)417   TraceID(long long id, unsigned int* flags)
418       : data_(static_cast<unsigned long long>(id)) { (void)flags; }
TraceID(long id,unsigned int * flags)419   TraceID(long id, unsigned int* flags)
420       : data_(static_cast<unsigned long long>(id)) { (void)flags; }
TraceID(int id,unsigned int * flags)421   TraceID(int id, unsigned int* flags)
422       : data_(static_cast<unsigned long long>(id)) { (void)flags; }
TraceID(short id,unsigned int * flags)423   TraceID(short id, unsigned int* flags)
424       : data_(static_cast<unsigned long long>(id)) { (void)flags; }
TraceID(signed char id,unsigned int * flags)425   TraceID(signed char id, unsigned int* flags)
426       : data_(static_cast<unsigned long long>(id)) { (void)flags; }
427 
data()428   unsigned long long data() const { return data_; }
429 
430  private:
431   unsigned long long data_;
432 };
433 
434 // Simple union to store various types as unsigned long long.
435 union TraceValueUnion {
436   bool as_bool;
437   unsigned long long as_uint;
438   long long as_int;
439   double as_double;
440   const void* as_pointer;
441   const char* as_string;
442 };
443 
444 // Simple container for const char* that should be copied instead of retained.
445 class TraceStringWithCopy {
446  public:
TraceStringWithCopy(const char * str)447   explicit TraceStringWithCopy(const char* str) : str_(str) {}
str()448   const char* str() const { return str_; }
449  private:
450   const char* str_;
451 };
452 
453 // Define SetTraceValue for each allowed type. It stores the type and
454 // value in the return arguments. This allows this API to avoid declaring any
455 // structures so that it is portable to third_party libraries.
456 #define INTERNAL_DECLARE_SET_TRACE_VALUE(actual_type, \
457                                          arg_expression, \
458                                          union_member, \
459                                          value_type_id) \
460     static inline void SetTraceValue( \
461         actual_type arg, \
462         unsigned char* type, \
463         unsigned long long* value) { \
464       TraceValueUnion type_value; \
465       type_value.union_member = arg_expression; \
466       *type = value_type_id; \
467       *value = type_value.as_uint; \
468     }
469 // Simpler form for int types that can be safely casted.
470 #define INTERNAL_DECLARE_SET_TRACE_VALUE_INT(actual_type, \
471                                              value_type_id) \
472     static inline void SetTraceValue( \
473         actual_type arg, \
474         unsigned char* type, \
475         unsigned long long* value) { \
476       *type = value_type_id; \
477       *value = static_cast<unsigned long long>(arg); \
478     }
479 
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned long long,TRACE_VALUE_TYPE_UINT)480 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned long long, TRACE_VALUE_TYPE_UINT)
481 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned long, TRACE_VALUE_TYPE_UINT)
482 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned int, TRACE_VALUE_TYPE_UINT)
483 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned short, TRACE_VALUE_TYPE_UINT)
484 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned char, TRACE_VALUE_TYPE_UINT)
485 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long long, TRACE_VALUE_TYPE_INT)
486 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long, TRACE_VALUE_TYPE_INT)
487 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(int, TRACE_VALUE_TYPE_INT)
488 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(short, TRACE_VALUE_TYPE_INT)
489 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(signed char, TRACE_VALUE_TYPE_INT)
490 INTERNAL_DECLARE_SET_TRACE_VALUE(bool, arg, as_bool, TRACE_VALUE_TYPE_BOOL)
491 INTERNAL_DECLARE_SET_TRACE_VALUE(double, arg, as_double,
492                                  TRACE_VALUE_TYPE_DOUBLE)
493 INTERNAL_DECLARE_SET_TRACE_VALUE(const void*, arg, as_pointer,
494                                  TRACE_VALUE_TYPE_POINTER)
495 INTERNAL_DECLARE_SET_TRACE_VALUE(const char*, arg, as_string,
496                                  TRACE_VALUE_TYPE_STRING)
497 INTERNAL_DECLARE_SET_TRACE_VALUE(const TraceStringWithCopy&, arg.str(),
498                                  as_string, TRACE_VALUE_TYPE_COPY_STRING)
499 
500 #undef INTERNAL_DECLARE_SET_TRACE_VALUE
501 #undef INTERNAL_DECLARE_SET_TRACE_VALUE_INT
502 
503 // std::string version of SetTraceValue so that trace arguments can be strings.
504 static inline void SetTraceValue(const std::string& arg,
505                                  unsigned char* type,
506                                  unsigned long long* value) {
507   TraceValueUnion type_value;
508   type_value.as_string = arg.c_str();
509   *type = TRACE_VALUE_TYPE_COPY_STRING;
510   *value = type_value.as_uint;
511 }
512 
513 // base::Time, base::TimeTicks, etc. versions of SetTraceValue to make it easier
514 // to trace these types.
SetTraceValue(const base::Time arg,unsigned char * type,unsigned long long * value)515 static inline void SetTraceValue(const base::Time arg,
516                                  unsigned char* type,
517                                  unsigned long long* value) {
518   *type = TRACE_VALUE_TYPE_INT;
519   *value = arg.ToInternalValue();
520 }
521 
SetTraceValue(const base::TimeTicks arg,unsigned char * type,unsigned long long * value)522 static inline void SetTraceValue(const base::TimeTicks arg,
523                                  unsigned char* type,
524                                  unsigned long long* value) {
525   *type = TRACE_VALUE_TYPE_INT;
526   *value = arg.ToInternalValue();
527 }
528 
SetTraceValue(const base::ThreadTicks arg,unsigned char * type,unsigned long long * value)529 static inline void SetTraceValue(const base::ThreadTicks arg,
530                                  unsigned char* type,
531                                  unsigned long long* value) {
532   *type = TRACE_VALUE_TYPE_INT;
533   *value = arg.ToInternalValue();
534 }
535 
536 // These AddTraceEvent and AddTraceEventWithThreadIdAndTimestamp template
537 // functions are defined here instead of in the macro, because the arg_values
538 // could be temporary objects, such as std::string. In order to store
539 // pointers to the internal c_str and pass through to the tracing API,
540 // the arg_values must live throughout these procedures.
541 
542 static inline base::trace_event::TraceEventHandle
AddTraceEventWithThreadIdAndTimestamp(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,int thread_id,const base::TimeTicks & timestamp,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const scoped_refptr<base::trace_event::ConvertableToTraceFormat> & arg1_val)543 AddTraceEventWithThreadIdAndTimestamp(
544     char phase,
545     const unsigned char* category_group_enabled,
546     const char* name,
547     unsigned long long id,
548     int thread_id,
549     const base::TimeTicks& timestamp,
550     unsigned int flags,
551     unsigned long long bind_id,
552     const char* arg1_name,
553     const scoped_refptr<base::trace_event::ConvertableToTraceFormat>&
554         arg1_val) {
555   const int num_args = 1;
556   unsigned char arg_types[1] = { TRACE_VALUE_TYPE_CONVERTABLE };
557   return TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
558       phase, category_group_enabled, name, id, bind_id, thread_id, timestamp,
559       num_args, &arg1_name, arg_types, NULL, &arg1_val, flags);
560 }
561 
562 template<class ARG1_TYPE>
563 static inline base::trace_event::TraceEventHandle
AddTraceEventWithThreadIdAndTimestamp(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,int thread_id,const base::TimeTicks & timestamp,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const ARG1_TYPE & arg1_val,const char * arg2_name,const scoped_refptr<base::trace_event::ConvertableToTraceFormat> & arg2_val)564 AddTraceEventWithThreadIdAndTimestamp(
565     char phase,
566     const unsigned char* category_group_enabled,
567     const char* name,
568     unsigned long long id,
569     int thread_id,
570     const base::TimeTicks& timestamp,
571     unsigned int flags,
572     unsigned long long bind_id,
573     const char* arg1_name,
574     const ARG1_TYPE& arg1_val,
575     const char* arg2_name,
576     const scoped_refptr<base::trace_event::ConvertableToTraceFormat>&
577         arg2_val) {
578   const int num_args = 2;
579   const char* arg_names[2] = { arg1_name, arg2_name };
580 
581   unsigned char arg_types[2];
582   unsigned long long arg_values[2];
583   SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
584   arg_types[1] = TRACE_VALUE_TYPE_CONVERTABLE;
585 
586   scoped_refptr<base::trace_event::ConvertableToTraceFormat>
587       convertable_values[2];
588   convertable_values[1] = arg2_val;
589 
590   return TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
591       phase, category_group_enabled, name, id, bind_id, thread_id, timestamp,
592       num_args, arg_names, arg_types, arg_values, convertable_values, flags);
593 }
594 
595 template<class ARG2_TYPE>
596 static inline base::trace_event::TraceEventHandle
AddTraceEventWithThreadIdAndTimestamp(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,int thread_id,const base::TimeTicks & timestamp,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const scoped_refptr<base::trace_event::ConvertableToTraceFormat> & arg1_val,const char * arg2_name,const ARG2_TYPE & arg2_val)597 AddTraceEventWithThreadIdAndTimestamp(
598     char phase,
599     const unsigned char* category_group_enabled,
600     const char* name,
601     unsigned long long id,
602     int thread_id,
603     const base::TimeTicks& timestamp,
604     unsigned int flags,
605     unsigned long long bind_id,
606     const char* arg1_name,
607     const scoped_refptr<base::trace_event::ConvertableToTraceFormat>& arg1_val,
608     const char* arg2_name,
609     const ARG2_TYPE& arg2_val) {
610   const int num_args = 2;
611   const char* arg_names[2] = { arg1_name, arg2_name };
612 
613   unsigned char arg_types[2];
614   unsigned long long arg_values[2];
615   arg_types[0] = TRACE_VALUE_TYPE_CONVERTABLE;
616   arg_values[0] = 0;
617   SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
618 
619   scoped_refptr<base::trace_event::ConvertableToTraceFormat>
620       convertable_values[2];
621   convertable_values[0] = arg1_val;
622 
623   return TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
624       phase, category_group_enabled, name, id, bind_id, thread_id, timestamp,
625       num_args, arg_names, arg_types, arg_values, convertable_values, flags);
626 }
627 
628 static inline base::trace_event::TraceEventHandle
AddTraceEventWithThreadIdAndTimestamp(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,int thread_id,const base::TimeTicks & timestamp,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const scoped_refptr<base::trace_event::ConvertableToTraceFormat> & arg1_val,const char * arg2_name,const scoped_refptr<base::trace_event::ConvertableToTraceFormat> & arg2_val)629 AddTraceEventWithThreadIdAndTimestamp(
630     char phase,
631     const unsigned char* category_group_enabled,
632     const char* name,
633     unsigned long long id,
634     int thread_id,
635     const base::TimeTicks& timestamp,
636     unsigned int flags,
637     unsigned long long bind_id,
638     const char* arg1_name,
639     const scoped_refptr<base::trace_event::ConvertableToTraceFormat>& arg1_val,
640     const char* arg2_name,
641     const scoped_refptr<base::trace_event::ConvertableToTraceFormat>&
642         arg2_val) {
643   const int num_args = 2;
644   const char* arg_names[2] = { arg1_name, arg2_name };
645   unsigned char arg_types[2] =
646       { TRACE_VALUE_TYPE_CONVERTABLE, TRACE_VALUE_TYPE_CONVERTABLE };
647   scoped_refptr<base::trace_event::ConvertableToTraceFormat>
648       convertable_values[2] = {arg1_val, arg2_val};
649 
650   return TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
651       phase, category_group_enabled, name, id, bind_id, thread_id, timestamp,
652       num_args, arg_names, arg_types, NULL, convertable_values, flags);
653 }
654 
655 static inline base::trace_event::TraceEventHandle
AddTraceEventWithThreadIdAndTimestamp(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,int thread_id,const base::TimeTicks & timestamp,unsigned int flags,unsigned long long bind_id)656 AddTraceEventWithThreadIdAndTimestamp(
657     char phase,
658     const unsigned char* category_group_enabled,
659     const char* name,
660     unsigned long long id,
661     int thread_id,
662     const base::TimeTicks& timestamp,
663     unsigned int flags,
664     unsigned long long bind_id) {
665   return TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
666       phase, category_group_enabled, name, id, bind_id, thread_id, timestamp,
667       kZeroNumArgs, NULL, NULL, NULL, NULL, flags);
668 }
669 
AddTraceEvent(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,unsigned int flags,unsigned long long bind_id)670 static inline base::trace_event::TraceEventHandle AddTraceEvent(
671     char phase,
672     const unsigned char* category_group_enabled,
673     const char* name,
674     unsigned long long id,
675     unsigned int flags,
676     unsigned long long bind_id) {
677   const int thread_id = static_cast<int>(base::PlatformThread::CurrentId());
678   const base::TimeTicks now = base::TimeTicks::Now();
679   return AddTraceEventWithThreadIdAndTimestamp(
680       phase, category_group_enabled, name, id, thread_id, now, flags, bind_id);
681 }
682 
683 template<class ARG1_TYPE>
684 static inline base::trace_event::TraceEventHandle
AddTraceEventWithThreadIdAndTimestamp(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,int thread_id,const base::TimeTicks & timestamp,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const ARG1_TYPE & arg1_val)685 AddTraceEventWithThreadIdAndTimestamp(
686     char phase,
687     const unsigned char* category_group_enabled,
688     const char* name,
689     unsigned long long id,
690     int thread_id,
691     const base::TimeTicks& timestamp,
692     unsigned int flags,
693     unsigned long long bind_id,
694     const char* arg1_name,
695     const ARG1_TYPE& arg1_val) {
696   const int num_args = 1;
697   unsigned char arg_types[1];
698   unsigned long long arg_values[1];
699   SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
700   return TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
701       phase, category_group_enabled, name, id, bind_id, thread_id, timestamp,
702       num_args, &arg1_name, arg_types, arg_values, NULL, flags);
703 }
704 
705 template<class ARG1_TYPE>
AddTraceEvent(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const ARG1_TYPE & arg1_val)706 static inline base::trace_event::TraceEventHandle AddTraceEvent(
707     char phase,
708     const unsigned char* category_group_enabled,
709     const char* name,
710     unsigned long long id,
711     unsigned int flags,
712     unsigned long long bind_id,
713     const char* arg1_name,
714     const ARG1_TYPE& arg1_val) {
715   int thread_id = static_cast<int>(base::PlatformThread::CurrentId());
716   base::TimeTicks now = base::TimeTicks::Now();
717   return AddTraceEventWithThreadIdAndTimestamp(phase, category_group_enabled,
718                                                name, id, thread_id, now, flags,
719                                                bind_id, arg1_name, arg1_val);
720 }
721 
722 template<class ARG1_TYPE, class ARG2_TYPE>
723 static inline base::trace_event::TraceEventHandle
AddTraceEventWithThreadIdAndTimestamp(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,int thread_id,const base::TimeTicks & timestamp,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const ARG1_TYPE & arg1_val,const char * arg2_name,const ARG2_TYPE & arg2_val)724 AddTraceEventWithThreadIdAndTimestamp(
725     char phase,
726     const unsigned char* category_group_enabled,
727     const char* name,
728     unsigned long long id,
729     int thread_id,
730     const base::TimeTicks& timestamp,
731     unsigned int flags,
732     unsigned long long bind_id,
733     const char* arg1_name,
734     const ARG1_TYPE& arg1_val,
735     const char* arg2_name,
736     const ARG2_TYPE& arg2_val) {
737   const int num_args = 2;
738   const char* arg_names[2] = { arg1_name, arg2_name };
739   unsigned char arg_types[2];
740   unsigned long long arg_values[2];
741   SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
742   SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
743   return TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
744       phase, category_group_enabled, name, id, bind_id, thread_id, timestamp,
745       num_args, arg_names, arg_types, arg_values, NULL, flags);
746 }
747 
748 template<class ARG1_TYPE, class ARG2_TYPE>
AddTraceEvent(char phase,const unsigned char * category_group_enabled,const char * name,unsigned long long id,unsigned int flags,unsigned long long bind_id,const char * arg1_name,const ARG1_TYPE & arg1_val,const char * arg2_name,const ARG2_TYPE & arg2_val)749 static inline base::trace_event::TraceEventHandle AddTraceEvent(
750     char phase,
751     const unsigned char* category_group_enabled,
752     const char* name,
753     unsigned long long id,
754     unsigned int flags,
755     unsigned long long bind_id,
756     const char* arg1_name,
757     const ARG1_TYPE& arg1_val,
758     const char* arg2_name,
759     const ARG2_TYPE& arg2_val) {
760   int thread_id = static_cast<int>(base::PlatformThread::CurrentId());
761   base::TimeTicks now = base::TimeTicks::Now();
762   return AddTraceEventWithThreadIdAndTimestamp(
763       phase, category_group_enabled, name, id, thread_id, now, flags, bind_id,
764       arg1_name, arg1_val, arg2_name, arg2_val);
765 }
766 
AddMetadataEvent(const char * event_name,const char * arg_name,scoped_refptr<base::trace_event::ConvertableToTraceFormat> arg_value)767 static inline void AddMetadataEvent(
768     const char* event_name,
769     const char* arg_name,
770     scoped_refptr<base::trace_event::ConvertableToTraceFormat> arg_value) {
771   const char* arg_names[1] = {arg_name};
772   scoped_refptr<base::trace_event::ConvertableToTraceFormat>
773       convertable_values[1] = {arg_value};
774   unsigned char arg_types[1] = {TRACE_VALUE_TYPE_CONVERTABLE};
775   base::trace_event::TraceLog::GetInstance()->AddMetadataEvent(
776       event_name,
777       1,  // num_args
778       arg_names, arg_types,
779       nullptr,  // arg_values
780       convertable_values, TRACE_EVENT_FLAG_NONE);
781 }
782 
783 template <class ARG1_TYPE>
AddMetadataEvent(const char * event_name,const char * arg_name,const ARG1_TYPE & arg_val)784 static void AddMetadataEvent(const char* event_name,
785                              const char* arg_name,
786                              const ARG1_TYPE& arg_val) {
787   const int num_args = 1;
788   const char* arg_names[1] = {arg_name};
789   unsigned char arg_types[1];
790   unsigned long long arg_values[1];
791   SetTraceValue(arg_val, &arg_types[0], &arg_values[0]);
792 
793   base::trace_event::TraceLog::GetInstance()->AddMetadataEvent(
794       event_name, num_args, arg_names, arg_types, arg_values, nullptr,
795       TRACE_EVENT_FLAG_NONE);
796 }
797 
798 // Used by TRACE_EVENTx macros. Do not use directly.
799 class TRACE_EVENT_API_CLASS_EXPORT ScopedTracer {
800  public:
801   // Note: members of data_ intentionally left uninitialized. See Initialize.
ScopedTracer()802   ScopedTracer() : p_data_(NULL) {}
803 
~ScopedTracer()804   ~ScopedTracer() {
805     if (p_data_ && *data_.category_group_enabled)
806       TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
807           data_.category_group_enabled, data_.name, data_.event_handle);
808   }
809 
Initialize(const unsigned char * category_group_enabled,const char * name,base::trace_event::TraceEventHandle event_handle)810   void Initialize(const unsigned char* category_group_enabled,
811                   const char* name,
812                   base::trace_event::TraceEventHandle event_handle) {
813     data_.category_group_enabled = category_group_enabled;
814     data_.name = name;
815     data_.event_handle = event_handle;
816     p_data_ = &data_;
817   }
818 
819  private:
820   // This Data struct workaround is to avoid initializing all the members
821   // in Data during construction of this object, since this object is always
822   // constructed, even when tracing is disabled. If the members of Data were
823   // members of this class instead, compiler warnings occur about potential
824   // uninitialized accesses.
825   struct Data {
826     const unsigned char* category_group_enabled;
827     const char* name;
828     base::trace_event::TraceEventHandle event_handle;
829   };
830   Data* p_data_;
831   Data data_;
832 };
833 
834 // Used by TRACE_EVENT_BINARY_EFFICIENTx macro. Do not use directly.
835 class TRACE_EVENT_API_CLASS_EXPORT ScopedTraceBinaryEfficient {
836  public:
837   ScopedTraceBinaryEfficient(const char* category_group, const char* name);
838   ~ScopedTraceBinaryEfficient();
839 
840  private:
841   const unsigned char* category_group_enabled_;
842   const char* name_;
843   base::trace_event::TraceEventHandle event_handle_;
844 };
845 
846 // This macro generates less code then TRACE_EVENT0 but is also
847 // slower to execute when tracing is off. It should generally only be
848 // used with code that is seldom executed or conditionally executed
849 // when debugging.
850 // For now the category_group must be "gpu".
851 #define TRACE_EVENT_BINARY_EFFICIENT0(category_group, name) \
852     trace_event_internal::ScopedTraceBinaryEfficient \
853         INTERNAL_TRACE_EVENT_UID(scoped_trace)(category_group, name);
854 
855 // TraceEventSamplingStateScope records the current sampling state
856 // and sets a new sampling state. When the scope exists, it restores
857 // the sampling state having recorded.
858 template<size_t BucketNumber>
859 class TraceEventSamplingStateScope {
860  public:
TraceEventSamplingStateScope(const char * category_and_name)861   TraceEventSamplingStateScope(const char* category_and_name) {
862     previous_state_ = TraceEventSamplingStateScope<BucketNumber>::Current();
863     TraceEventSamplingStateScope<BucketNumber>::Set(category_and_name);
864   }
865 
~TraceEventSamplingStateScope()866   ~TraceEventSamplingStateScope() {
867     TraceEventSamplingStateScope<BucketNumber>::Set(previous_state_);
868   }
869 
Current()870   static inline const char* Current() {
871     return reinterpret_cast<const char*>(TRACE_EVENT_API_ATOMIC_LOAD(
872       g_trace_state[BucketNumber]));
873   }
874 
Set(const char * category_and_name)875   static inline void Set(const char* category_and_name) {
876     TRACE_EVENT_API_ATOMIC_STORE(
877       g_trace_state[BucketNumber],
878       reinterpret_cast<TRACE_EVENT_API_ATOMIC_WORD>(
879         const_cast<char*>(category_and_name)));
880   }
881 
882  private:
883   const char* previous_state_;
884 };
885 
886 }  // namespace trace_event_internal
887 
888 namespace base {
889 namespace trace_event {
890 
891 template<typename IDType> class TraceScopedTrackableObject {
892  public:
TraceScopedTrackableObject(const char * category_group,const char * name,IDType id)893   TraceScopedTrackableObject(const char* category_group, const char* name,
894       IDType id)
895     : category_group_(category_group),
896       name_(name),
897       id_(id) {
898     TRACE_EVENT_OBJECT_CREATED_WITH_ID(category_group_, name_, id_);
899   }
900 
snapshot(ArgType snapshot)901   template <typename ArgType> void snapshot(ArgType snapshot) {
902     TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(category_group_, name_, id_, snapshot);
903   }
904 
~TraceScopedTrackableObject()905   ~TraceScopedTrackableObject() {
906     TRACE_EVENT_OBJECT_DELETED_WITH_ID(category_group_, name_, id_);
907   }
908 
909  private:
910   const char* category_group_;
911   const char* name_;
912   IDType id_;
913 
914   DISALLOW_COPY_AND_ASSIGN(TraceScopedTrackableObject);
915 };
916 
917 }  // namespace trace_event
918 }  // namespace base
919 
920 #endif  // BASE_TRACE_EVENT_TRACE_EVENT_H_
921