Tracing pre-filtering

base/trace_event/trace_log.h

 // Copyright 2015 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.
 
 #ifndef BASE_TRACE_EVENT_TRACE_LOG_H_
 #define BASE_TRACE_EVENT_TRACE_LOG_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 42 matching lines @@
   // The pointer returned from GetCategoryGroupEnabledInternal() points to a
   // value with zero or more of the following bits. Used in this class only.
   // The TRACE_EVENT macros should only use the value as a bool.
   // These values must be in sync with macro values in TraceEvent.h in Blink.
   enum CategoryGroupEnabledFlags {
     // Category group enabled for the recording mode.
     ENABLED_FOR_RECORDING = 1 << 0,
     // Category group enabled by SetEventCallbackEnabled().
     ENABLED_FOR_EVENT_CALLBACK = 1 << 2,
     // Category group enabled to export events to ETW.
-    ENABLED_FOR_ETW_EXPORT = 1 << 3
+    ENABLED_FOR_ETW_EXPORT = 1 << 3,
+    // Category group being filtered before logged.
+    ENABLED_FOR_FILTERING = 1 << 4
   };
 
   static TraceLog* GetInstance();
 
   // Get set of known category groups. This can change as new code paths are
   // reached. The known category groups are inserted into |category_groups|.
   void GetKnownCategoryGroups(std::vector<std::string>* category_groups);
 
   // Retrieves a copy (for thread-safety) of the current TraceConfig.
   TraceConfig GetCurrentTraceConfig() const;
@@ skipping 205 matching lines @@
       const char** arg_names,
       const unsigned char* arg_types,
       const unsigned long long* arg_values,
       std::unique_ptr<ConvertableToTraceFormat>* convertable_values,
       unsigned int flags);
 
   void UpdateTraceEventDuration(const unsigned char* category_group_enabled,
                                 const char* name,
                                 TraceEventHandle handle);
 
+  void EndFilteredEvent(const unsigned char* category_group_enabled,
+                        const char* name,
+                        TraceEventHandle handle);
+
   // For every matching event, the callback will be called.
   typedef base::Callback<void()> WatchEventCallback;
   void SetWatchEvent(const std::string& category_name,
                      const std::string& event_name,
                      const WatchEventCallback& callback);
   // Cancel the watch event. If tracing is enabled, this may race with the
   // watch event notification firing.
   void CancelWatchEvent();
 
   int process_id() const { return process_id_; }
 
   uint64_t MangleEventId(uint64_t id);
 
   // Exposed for unittesting:
 
   void WaitSamplingEventForTesting();
 
   // Allows deleting our singleton instance.
   static void DeleteForTesting();
 
+  class TraceEventFilter {
+   public:
+    TraceEventFilter() {}
+    virtual ~TraceEventFilter() {}
+    virtual bool FilterTraceEvent(const TraceEvent& trace_event) const = 0;
+    virtual void EndEvent(const char* category_group, const char* name) {}
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(TraceEventFilter);
+  };
+  typedef std::unique_ptr<TraceEventFilter> (
+      *TraceEventFilterConstructorForTesting)(void);
+  static void SetTraceEventFilterConstructorForTesting(
+      TraceEventFilterConstructorForTesting predicate);
+
   // Allow tests to inspect TraceEvents.
   TraceEvent* GetEventByHandle(TraceEventHandle handle);
 
   void SetProcessID(int process_id);
 
   // Process sort indices, if set, override the order of a process will appear
   // relative to other processes in the trace viewer. Processes are sorted first
   // on their sort index, ascending, then by their name, and then tid.
   void SetProcessSortIndex(int sort_index);
 
@@ skipping 204 matching lines @@
   subtle::AtomicWord generation_;
   bool use_worker_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceLog);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_TRACE_LOG_H_