Index: base/trace_event/trace_event_filter.h |
diff --git a/base/trace_event/trace_event_filter.h b/base/trace_event/trace_event_filter.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..48c6711432fdadc013b3b6ca5be668d42337e98e |
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+++ b/base/trace_event/trace_event_filter.h |
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+// Copyright 2016 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_EVENT_FILTER_H_ |
+#define BASE_TRACE_EVENT_TRACE_EVENT_FILTER_H_ |
+ |
+#include <memory> |
+ |
+#include "base/base_export.h" |
+#include "base/macros.h" |
+ |
+namespace base { |
+namespace trace_event { |
+ |
+class TraceEvent; |
+ |
+// TraceEventFilter is like iptables for TRACE_EVENT macros. Filters can be |
+// enabled on a per-category basis, hence a single filter instance can serve |
+// more than a TraceCategory. There are two use cases for filters: |
+// 1. Snooping TRACE_EVENT macros without adding them to the TraceLog. This is |
+// possible by setting the ENABLED_FOR_FILTERING flag on a category w/o |
+// ENABLED_FOR_RECORDING (see TraceConfig for user-facing configuration). |
+// 2. Filtering TRACE_EVENT macros before they are added to the TraceLog. This |
+// requires both the ENABLED_FOR_FILTERING and ENABLED_FOR_RECORDING flags |
+// on the category. |
+// More importantly, filters must be thread-safe. The FilterTraceEvent and |
+// EndEvent methods can be called concurrently as trace macros are hit on |
+// different threads. |
+class BASE_EXPORT TraceEventFilter { |
+ public: |
+ TraceEventFilter(); |
+ virtual ~TraceEventFilter(); |
+ |
+ // If the category is ENABLED_FOR_RECORDING, the event is added iff all the |
+ // filters enabled for the category return true. false causes the event to be |
+ // discarded. |
+ virtual bool FilterTraceEvent(const TraceEvent& trace_event) const = 0; |
+ |
+ // Notifies the end of a duration event when the RAII macro goes out of scope. |
+ virtual void EndEvent(const char* category_name, |
+ const char* event_name) const; |
+ |
+ private: |
+ DISALLOW_COPY_AND_ASSIGN(TraceEventFilter); |
+}; |
+ |
+} // namespace trace_event |
+} // namespace base |
+ |
+#endif // BASE_TRACE_EVENT_TRACE_EVENT_FILTER_H_ |