base: Add blame context

base/debug/blame_context_unittest.cc

Index: base/debug/blame_context_unittest.cc
diff --git a/base/debug/blame_context_unittest.cc b/base/debug/blame_context_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..32a130dd1aa10a78c04db302a0f73ada54112f9f
--- /dev/null
+++ b/base/debug/blame_context_unittest.cc
@@ -0,0 +1,190 @@
+// 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.
+
+#include "base/debug/blame_context.h"
+
+#include "base/json/json_writer.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/run_loop.h"
+#include "base/test/trace_event_analyzer.h"
+#include "base/trace_event/trace_buffer.h"
+#include "base/trace_event/trace_event_argument.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace debug {
+namespace {
+
+const char kTestBlameCategory[] = "test";
+const char kDisabledTestBlameCategory[] = "disabled-by-default-test";
+const char kTestBlameName[] = "TestBlameContext";
+const char kTestBlameScope[] = "TestBlameScope";
+
+class TestBlameContext : public BlameContext {
+ public:
+  explicit TestBlameContext(int id)
+      : BlameContext(kTestBlameCategory, kTestBlameName, kTestBlameScope, id) {}
+
+  TestBlameContext(int id, const TestBlameContext& parent)
+      : BlameContext(kTestBlameCategory,
+                     kTestBlameName,
+                     kTestBlameScope,
+                     id,
+                     parent) {}
+
+ protected:
+  void AsValueInto(trace_event::TracedValue* state) override {
+    BlameContext::AsValueInto(state);
+    state->SetBoolean("crossStreams", false);
+  }
+};
+
+class DisabledTestBlameContext : public BlameContext {
+ public:
+  explicit DisabledTestBlameContext(int id)
+      : BlameContext(kDisabledTestBlameCategory,
+                     kTestBlameName,
+                     kTestBlameScope,
+                     id) {}
+};
+
+void OnTraceDataCollected(Closure quit_closure,
+                          trace_event::TraceResultBuffer* buffer,
+                          const scoped_refptr<RefCountedString>& json,
+                          bool has_more_events) {
+  buffer->AddFragment(json->data());
+  if (!has_more_events)
+    quit_closure.Run();
+}
+
+class BlameContextTest : public testing::Test {
+ public:
+  void StartTracing();
+  void StopTracing();
+  scoped_ptr<trace_analyzer::TraceAnalyzer> CreateTraceAnalyzer();
+};
+
+void BlameContextTest::StartTracing() {
+  trace_event::TraceLog::GetInstance()->SetEnabled(
+      trace_event::TraceConfig("*"), trace_event::TraceLog::RECORDING_MODE);
+}
+
+void BlameContextTest::StopTracing() {
+  trace_event::TraceLog::GetInstance()->SetDisabled();
+}
+
+scoped_ptr<trace_analyzer::TraceAnalyzer>
+BlameContextTest::CreateTraceAnalyzer() {
+  trace_event::TraceResultBuffer buffer;
+  trace_event::TraceResultBuffer::SimpleOutput trace_output;
+  buffer.SetOutputCallback(trace_output.GetCallback());
+  RunLoop run_loop;
+  buffer.Start();
+  trace_event::TraceLog::GetInstance()->Flush(
+      Bind(&OnTraceDataCollected, run_loop.QuitClosure(), Unretained(&buffer)));
+  run_loop.Run();
+  buffer.Finish();
+
+  return make_scoped_ptr(
+      trace_analyzer::TraceAnalyzer::Create(trace_output.json_output));
+}
+
+TEST_F(BlameContextTest, EnterAndLeave) {
+  using trace_analyzer::Query;
+  StartTracing();
+  {
+    TestBlameContext blame_context(0x1234);
+    blame_context.Enter();
+    blame_context.Leave();
+  }
+  StopTracing();
+  scoped_ptr<trace_analyzer::TraceAnalyzer> analyzer = CreateTraceAnalyzer();
+
+  trace_analyzer::TraceEventVector events;
+  Query q = Query::EventPhaseIs(TRACE_EVENT_PHASE_ENTER_CONTEXT) ||
+            Query::EventPhaseIs(TRACE_EVENT_PHASE_LEAVE_CONTEXT);
+  analyzer->FindEvents(q, &events);
+
+  EXPECT_EQ(2u, events.size());
+  EXPECT_EQ(TRACE_EVENT_PHASE_ENTER_CONTEXT, events[0]->phase);
+  EXPECT_EQ(kTestBlameCategory, events[0]->category);
+  EXPECT_EQ(kTestBlameName, events[0]->name);
+  EXPECT_EQ("0x1234", events[0]->id);
+  EXPECT_EQ(TRACE_EVENT_PHASE_LEAVE_CONTEXT, events[1]->phase);
+  EXPECT_EQ(kTestBlameCategory, events[1]->category);
+  EXPECT_EQ(kTestBlameName, events[1]->name);
+  EXPECT_EQ("0x1234", events[1]->id);
+}
+
+TEST_F(BlameContextTest, DifferentCategories) {
+  // Ensure there is no cross talk between blame contexts from different
+  // categories.
+  using trace_analyzer::Query;
+  StartTracing();
+  {
+    TestBlameContext blame_context(0x1234);
+    DisabledTestBlameContext disabled_blame_context(0x5678);
+    blame_context.Enter();
+    blame_context.Leave();
+    disabled_blame_context.Enter();
+    disabled_blame_context.Leave();
+  }
+  StopTracing();
+  scoped_ptr<trace_analyzer::TraceAnalyzer> analyzer = CreateTraceAnalyzer();
+
+  trace_analyzer::TraceEventVector events;
+  Query q = Query::EventPhaseIs(TRACE_EVENT_PHASE_ENTER_CONTEXT) ||
+            Query::EventPhaseIs(TRACE_EVENT_PHASE_LEAVE_CONTEXT);
+  analyzer->FindEvents(q, &events);
+
+  // None of the events from the disabled-by-default category should show up.
+  EXPECT_EQ(2u, events.size());
+  EXPECT_EQ(TRACE_EVENT_PHASE_ENTER_CONTEXT, events[0]->phase);
+  EXPECT_EQ(kTestBlameCategory, events[0]->category);
+  EXPECT_EQ(kTestBlameName, events[0]->name);
+  EXPECT_EQ("0x1234", events[0]->id);
+  EXPECT_EQ(TRACE_EVENT_PHASE_LEAVE_CONTEXT, events[1]->phase);
+  EXPECT_EQ(kTestBlameCategory, events[1]->category);
+  EXPECT_EQ(kTestBlameName, events[1]->name);
+  EXPECT_EQ("0x1234", events[1]->id);
+}
+
+TEST_F(BlameContextTest, TakeSnapshot) {
+  using trace_analyzer::Query;
+  StartTracing();
+  {
+    TestBlameContext parent_blame_context(0x5678);
+    TestBlameContext blame_context(0x1234, parent_blame_context);
+    blame_context.TakeSnapshot();
+  }
+  StopTracing();
+  scoped_ptr<trace_analyzer::TraceAnalyzer> analyzer = CreateTraceAnalyzer();
+
+  trace_analyzer::TraceEventVector events;
+  Query q = Query::EventPhaseIs(TRACE_EVENT_PHASE_SNAPSHOT_OBJECT);
+  analyzer->FindEvents(q, &events);
+
+  EXPECT_EQ(1u, events.size());
+  EXPECT_EQ(kTestBlameCategory, events[0]->category);
+  EXPECT_EQ(kTestBlameName, events[0]->name);
+  EXPECT_EQ("0x1234", events[0]->id);
+  EXPECT_TRUE(events[0]->HasArg("snapshot"));
+
+  const char kExpectedSnapshotJson[] =
+      "{"
+          "\"crossStreams\":false,"
+          "\"parent\":{"
+              "\"id_ref\":\"0x5678\","
+              "\"scope\":\"TestBlameScope\""
+          "}"
+      "}";
+
+  std::string snapshot_json;
+  JSONWriter::Write(*events[0]->GetKnownArgAsValue("snapshot"), &snapshot_json);
+  EXPECT_EQ(kExpectedSnapshotJson, snapshot_json);
+}
+
+}  // namepace
+}  // namespace debug
+}  // namespace base