Tracing pre-filtering

base/trace_event/trace_event_unittest.cc

 // 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.
 
 #include "base/trace_event/trace_event.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 3081 matching lines @@
   config1.Merge(config2);
   EXPECT_EQ(2u, config1.GetSyntheticDelayValues().size());
 }
 
 TEST_F(TraceEventTestFixture, SyntheticDelayConfigurationToString) {
   const char filter[] = "DELAY(test.Delay;16;oneshot)";
   TraceConfig config(filter, "");
   EXPECT_EQ(filter, config.ToCategoryFilterString());
 }
 
+TEST_F(TraceEventTestFixture, EventFiltering) {
+  const char config_json[] =
+      "{"
+      "  \"included_categories\": ["
+      "    \"filtered_cat\","
+      "    \"unfiltered_cat\"],"
+      "  \"event_filters\": ["
+      "     {"
+      "       \"filter_predicate\": \"event_whitelist_predicate\", "
+      "       \"included_categories\": [\"*\"], "
+      "       \"excluded_categories\": [\"unfiltered_cat\"], "
+      "       \"filter_args\": {"
+      "           \"event_name_whitelist\": [\"a snake\", \"a dog\"]"
+      "         }"
+      "     }"
+      "    "
+      "  ]"
+      "}";
+
+  TraceConfig trace_config(config_json);
+  TraceLog::GetInstance()->SetEnabled(trace_config, TraceLog::RECORDING_MODE);
+  EXPECT_TRUE(TraceLog::GetInstance()->IsEnabled());
+
+  TRACE_EVENT0("filtered_cat", "a snake");
+  TRACE_EVENT0("filtered_cat", "a mushroom");
+  TRACE_EVENT0("unfiltered_cat", "a cat");
+
+  EndTraceAndFlush();
+
+  EXPECT_TRUE(FindMatchingValue("name", "a snake"));
+  EXPECT_FALSE(FindMatchingValue("name", "a mushroom"));
+  EXPECT_TRUE(FindMatchingValue("name", "a cat"));
+}
+
 }  // namespace trace_event
 }  // namespace base