Reland: Add trace event Pepper API

base/debug/trace_event_internal.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// This header is designed to give you trace_event macros without specifying
+// This header file defines the set of trace_event macros without specifying
 // how the events actually get collected and stored. If you need to expose trace
-// event to some other universe, you can copy-and-paste this file,
-// implement the TRACE_EVENT_API macros, and do any other necessary fixup for
-// the target platform. The end result is that multiple libraries can funnel
-// events through to a shared trace event collector.
+// events to some other universe, you can copy-and-paste this file as well as
+// trace_event.h, modifying the macros contained there as necessary for the
+// target platform. The end result is that multiple libraries can funnel events
+// through to a shared trace event collector.
 
 // Trace events are for tracking application performance and resource usage.
 // Macros are provided to track:
 //    Begin and end of function calls
 //    Counters
 //
 // Events are issued against categories. Whereas LOG's
 // categories are statically defined, TRACE categories are created
 // implicitly with a string. For example:
 //   TRACE_EVENT_INSTANT0("MY_SUBSYSTEM", "SomeImportantEvent")
@@ skipping 120 matching lines @@
 // the time of the system being enabled or disabled. This is acceptable as
 // we tolerate some data loss while the system is being enabled/disabled and
 // because AddTraceEvent is threadsafe internally and checks the enabled state
 // again under lock.
 //
 // Without the use of these static category pointers and enabled flags all
 // trace points would carry a significant performance cost of aquiring a lock
 // and resolving the category.
 
 
-#ifndef BASE_DEBUG_TRACE_EVENT_H_
-#define BASE_DEBUG_TRACE_EVENT_H_
+#ifndef BASE_DEBUG_TRACE_EVENT_INTERNAL_H_
+#define BASE_DEBUG_TRACE_EVENT_INTERNAL_H_
 
 #include <string>
 
-#include "base/atomicops.h"
-#include "base/debug/trace_event_impl.h"
-#include "build/build_config.h"
-
 // By default, const char* argument values are assumed to have long-lived scope
 // and will not be copied. Use this macro to force a const char* to be copied.
 #define TRACE_STR_COPY(str) \
     trace_event_internal::TraceStringWithCopy(str)
 
 // By default, uint64 ID argument values are not mangled with the Process ID in
 // TRACE_EVENT_ASYNC macros. Use this macro to force Process ID mangling.
 #define TRACE_ID_MANGLE(id) \
     trace_event_internal::TraceID::ForceMangle(id)
 
@@ skipping 368 matching lines @@
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, \
         category, name, id, TRACE_EVENT_FLAG_COPY, \
         arg1_name, arg1_val)
 #define TRACE_EVENT_COPY_FLOW_END2(category, name, id, arg1_name, arg1_val, \
         arg2_name, arg2_val) \
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, \
         category, name, id, TRACE_EVENT_FLAG_COPY, \
         arg1_name, arg1_val, arg2_name, arg2_val)
 
 
-////////////////////////////////////////////////////////////////////////////////
-// Implementation specific tracing API definitions.
-
-// Get a pointer to the enabled state of the given trace category. Only
-// long-lived literal strings should be given as the category name. The returned
-// pointer can be held permanently in a local static for example. If the
-// unsigned char is non-zero, tracing is enabled. If tracing is enabled,
-// TRACE_EVENT_API_ADD_TRACE_EVENT can be called. It's OK if tracing is disabled
-// between the load of the tracing state and the call to
-// TRACE_EVENT_API_ADD_TRACE_EVENT, because this flag only provides an early out
-// for best performance when tracing is disabled.
-// const unsigned char*
-//     TRACE_EVENT_API_GET_CATEGORY_ENABLED(const char* category_name)
-#define TRACE_EVENT_API_GET_CATEGORY_ENABLED \
-    base::debug::TraceLog::GetCategoryEnabled
-
-// Add a trace event to the platform tracing system.
-// void TRACE_EVENT_API_ADD_TRACE_EVENT(
-//                    char phase,
-//                    const unsigned char* category_enabled,
-//                    const char* name,
-//                    unsigned long long id,
-//                    int num_args,
-//                    const char** arg_names,
-//                    const unsigned char* arg_types,
-//                    const unsigned long long* arg_values,
-//                    unsigned char flags)
-#define TRACE_EVENT_API_ADD_TRACE_EVENT \
-    base::debug::TraceLog::GetInstance()->AddTraceEvent
-
-////////////////////////////////////////////////////////////////////////////////
-
 // Implementation detail: trace event macros create temporary variables
 // to keep instrumentation overhead low. These macros give each temporary
 // variable a unique name based on the line number to prevent name collissions.
 #define INTERNAL_TRACE_EVENT_UID3(a,b) \
     trace_event_unique_##a##b
 #define INTERNAL_TRACE_EVENT_UID2(a,b) \
     INTERNAL_TRACE_EVENT_UID3(a,b)
 #define INTERNAL_TRACE_EVENT_UID(name_prefix) \
     INTERNAL_TRACE_EVENT_UID2(name_prefix, __LINE__)
 
 // Implementation detail: internal macro to create static category.
 // No barriers are needed, because this code is designed to operate safely
 // even when the unsigned char* points to garbage data (which may be the case
 // on processors without cache coherency).
 #define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category) \
-    static base::subtle::AtomicWord INTERNAL_TRACE_EVENT_UID(atomic) = 0; \
-    const uint8* INTERNAL_TRACE_EVENT_UID(catstatic) = \
-        reinterpret_cast<const uint8*>( \
-            base::subtle::NoBarrier_Load(&INTERNAL_TRACE_EVENT_UID(atomic))); \
+    static TRACE_EVENT_API_ATOMIC_WORD INTERNAL_TRACE_EVENT_UID(atomic) = 0; \
+    const unsigned char* INTERNAL_TRACE_EVENT_UID(catstatic) = \
+        reinterpret_cast<const unsigned char*>(TRACE_EVENT_API_ATOMIC_LOAD( \
+            INTERNAL_TRACE_EVENT_UID(atomic))); \
     if (!INTERNAL_TRACE_EVENT_UID(catstatic)) { \
       INTERNAL_TRACE_EVENT_UID(catstatic) = \
           TRACE_EVENT_API_GET_CATEGORY_ENABLED(category); \
-      base::subtle::NoBarrier_Store(&INTERNAL_TRACE_EVENT_UID(atomic), \
-          reinterpret_cast<base::subtle::AtomicWord>( \
+      TRACE_EVENT_API_ATOMIC_STORE(INTERNAL_TRACE_EVENT_UID(atomic), \
+          reinterpret_cast<TRACE_EVENT_API_ATOMIC_WORD>( \
               INTERNAL_TRACE_EVENT_UID(catstatic))); \
     }
 
 // Implementation detail: internal macro to create static category and add
 // event if the category is enabled.
 #define INTERNAL_TRACE_EVENT_ADD(phase, category, name, flags, ...) \
     do { \
       INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category); \
       if (*INTERNAL_TRACE_EVENT_UID(catstatic)) { \
         trace_event_internal::AddTraceEvent( \
@@ skipping 221 matching lines @@
 // through to the tracing API, the arg_values must live throughout
 // these procedures.
 
 static inline void AddTraceEvent(char phase,
                                 const unsigned char* category_enabled,
                                 const char* name,
                                 unsigned long long id,
                                 unsigned char flags) {
   TRACE_EVENT_API_ADD_TRACE_EVENT(
       phase, category_enabled, name, id,
-      kZeroNumArgs, NULL, NULL, NULL,
-      flags);
+      kZeroNumArgs, NULL, NULL, NULL, flags);
 }
 
 template<class ARG1_TYPE>
 static inline void AddTraceEvent(char phase,
                                 const unsigned char* category_enabled,
                                 const char* name,
                                 unsigned long long id,
                                 unsigned char flags,
                                 const char* arg1_name,
                                 const ARG1_TYPE& arg1_val) {
   const int num_args = 1;
   unsigned char arg_types[1];
   unsigned long long arg_values[1];
   SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
   TRACE_EVENT_API_ADD_TRACE_EVENT(
       phase, category_enabled, name, id,
-      num_args, &arg1_name, arg_types, arg_values,
-      flags);
+      num_args, &arg1_name, arg_types, arg_values, flags);
 }
 
 template<class ARG1_TYPE, class ARG2_TYPE>
 static inline void AddTraceEvent(char phase,
                                 const unsigned char* category_enabled,
                                 const char* name,
                                 unsigned long long id,
                                 unsigned char flags,
                                 const char* arg1_name,
                                 const ARG1_TYPE& arg1_val,
                                 const char* arg2_name,
                                 const ARG2_TYPE& arg2_val) {
   const int num_args = 2;
   const char* arg_names[2] = { arg1_name, arg2_name };
   unsigned char arg_types[2];
   unsigned long long arg_values[2];
   SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
   SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
   TRACE_EVENT_API_ADD_TRACE_EVENT(
       phase, category_enabled, name, id,
-      num_args, arg_names, arg_types, arg_values,
-      flags);
+      num_args, arg_names, arg_types, arg_values, flags);
 }
 
 // Used by TRACE_EVENTx macro. Do not use directly.
-class BASE_EXPORT TraceEndOnScopeClose {
+class TRACE_EVENT_API_CLASS_EXPORT TraceEndOnScopeClose {
  public:
   // Note: members of data_ intentionally left uninitialized. See Initialize.
   TraceEndOnScopeClose() : p_data_(NULL) {}
   ~TraceEndOnScopeClose() {
     if (p_data_)
       AddEventIfEnabled();
   }
 
   void Initialize(const unsigned char* category_enabled,
-                  const char* name);
+                  const char* name) {
+    data_.category_enabled = category_enabled;
+    data_.name = name;
+    p_data_ = &data_;
+  }
+
 
  private:
   // Add the end event if the category is still enabled.
-  void AddEventIfEnabled();
+  void AddEventIfEnabled() {
+    // Only called when p_data_ is non-null.
+    if (*p_data_->category_enabled) {
+      TRACE_EVENT_API_ADD_TRACE_EVENT(
+          TRACE_EVENT_PHASE_END,
+          p_data_->category_enabled,
+          p_data_->name, kNoEventId,
+          kZeroNumArgs, NULL, NULL, NULL,
+          TRACE_EVENT_FLAG_NONE);
+    }
+  }
 
   // This Data struct workaround is to avoid initializing all the members
   // in Data during construction of this object, since this object is always
   // constructed, even when tracing is disabled. If the members of Data were
   // members of this class instead, compiler warnings occur about potential
   // uninitialized accesses.
   struct Data {
     const unsigned char* category_enabled;
     const char* name;
   };
   Data* p_data_;
   Data data_;
 };
 
-
 }  // namespace trace_event_internal
 
-#endif  // BASE_DEBUG_TRACE_EVENT_H_
+#endif  // BASE_DEBUG_TRACE_EVENT_INTERNAL_H_