Made logging macros evaluate its stream arguments lazily.

base/logging_unittest.cc

Index: base/logging_unittest.cc
diff --git a/base/logging_unittest.cc b/base/logging_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fa28ec6e373b953b3ba6d86cbc897f158b795535
--- /dev/null
+++ b/base/logging_unittest.cc
@@ -0,0 +1,154 @@
+// Copyright (c) 2010 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/basictypes.h"
+#include "base/logging.h"
+
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace logging {
+
+namespace {
+
+using ::testing::Return;
+
+// Class to make sure any manipulations we do to the min log level are
+// contained (i.e., do not affect other unit tests).
+class MinLogLevelSaver {
+ public:
+  MinLogLevelSaver() : old_min_log_level_(GetMinLogLevel()) {}
+
+  ~MinLogLevelSaver() { SetMinLogLevel(old_min_log_level_);  }
+
+ private:
+  int old_min_log_level_;
+
+  DISALLOW_COPY_AND_ASSIGN(MinLogLevelSaver);
+};
+
+class LoggingTest : public testing::Test {
+ private:
+  MinLogLevelSaver min_log_level_saver_;
+};
+
+class MockLogSource {
+ public:
+  MOCK_METHOD0(Log, const char*());
+};
+
+TEST_F(LoggingTest, BasicLogging) {
+  MockLogSource mock_log_source;
+  const int kExpectedDebugOrReleaseCalls = 6;
+  const int kExpectedDebugCalls = 6;
+  const int kExpectedCalls =
+      kExpectedDebugOrReleaseCalls + (DEBUG_MODE ? kExpectedDebugCalls : 0);
+  EXPECT_CALL(mock_log_source, Log()).Times(kExpectedCalls).
+      WillRepeatedly(Return("log message"));
+
+  SetMinLogLevel(LOG_INFO);
+
+  EXPECT_TRUE(LOG_IS_ON(INFO));
+  EXPECT_EQ(DEBUG_MODE != 0, DLOG_IS_ON(INFO));
+  EXPECT_TRUE(VLOG_IS_ON(0));
+
+  LOG(INFO) << mock_log_source.Log();
+  LOG_IF(INFO, true) << mock_log_source.Log();
+  PLOG(INFO) << mock_log_source.Log();
+  PLOG_IF(INFO, true) << mock_log_source.Log();
+  VLOG(0) << mock_log_source.Log();
+  VLOG_IF(0, true) << mock_log_source.Log();
+
+  DLOG(INFO) << mock_log_source.Log();
+  DLOG_IF(INFO, true) << mock_log_source.Log();
+  DPLOG(INFO) << mock_log_source.Log();
+  DPLOG_IF(INFO, true) << mock_log_source.Log();
+  DVLOG(0) << mock_log_source.Log();
+  DVLOG_IF(0, true) << mock_log_source.Log();
+}
+
+TEST_F(LoggingTest, LoggingIsLazy) {
+  MockLogSource mock_log_source;
+  EXPECT_CALL(mock_log_source, Log()).Times(0);
+
+  SetMinLogLevel(LOG_WARNING);
+
+  EXPECT_FALSE(LOG_IS_ON(INFO));
+  EXPECT_FALSE(DLOG_IS_ON(INFO));
+  EXPECT_FALSE(VLOG_IS_ON(1));
+
+  LOG(INFO) << mock_log_source.Log();
+  LOG_IF(INFO, false) << mock_log_source.Log();
+  PLOG(INFO) << mock_log_source.Log();
+  PLOG_IF(INFO, false) << mock_log_source.Log();
+  VLOG(1) << mock_log_source.Log();
+  VLOG_IF(1, true) << mock_log_source.Log();
+
+  DLOG(INFO) << mock_log_source.Log();
+  DLOG_IF(INFO, true) << mock_log_source.Log();
+  DPLOG(INFO) << mock_log_source.Log();
+  DPLOG_IF(INFO, true) << mock_log_source.Log();
+  DVLOG(1) << mock_log_source.Log();
+  DVLOG_IF(1, true) << mock_log_source.Log();
+}
+
+TEST_F(LoggingTest, ChecksAreNotLazy) {
+  MockLogSource mock_log_source, uncalled_mock_log_source;
+  EXPECT_CALL(mock_log_source, Log()).Times(8).
+      WillRepeatedly(Return("check message"));
+  EXPECT_CALL(uncalled_mock_log_source, Log()).Times(0);
+
+  SetMinLogLevel(LOG_FATAL + 1);
+  EXPECT_FALSE(LOG_IS_ON(FATAL));
+
+  CHECK(mock_log_source.Log()) << uncalled_mock_log_source.Log();
+  PCHECK(!mock_log_source.Log()) << mock_log_source.Log();
+  CHECK_EQ(mock_log_source.Log(), mock_log_source.Log())
+      << uncalled_mock_log_source.Log();
+  CHECK_NE(mock_log_source.Log(), mock_log_source.Log())
+      << mock_log_source.Log();
+}
+
+TEST_F(LoggingTest, DebugLoggingReleaseBehavior) {
+#if !defined(NDEBUG)
+  int debug_only_variable = 1;
+#endif
+  // These should avoid emitting references to |debug_only_variable|
+  // in release mode.
+  DLOG_IF(INFO, debug_only_variable) << "test";
+  DLOG_ASSERT(debug_only_variable) << "test";
+  DPLOG_IF(INFO, debug_only_variable) << "test";
+  DVLOG_IF(1, debug_only_variable) << "test";
+}
+
+TEST_F(LoggingTest, DchecksAreLazy) {
+  MockLogSource mock_log_source;
+  EXPECT_CALL(mock_log_source, Log()).Times(0);
+
+#if !defined(LOGGING_IS_OFFICIAL_BUILD) && defined(NDEBUG)
+  // Unofficial release build.
+  logging::g_enable_dcheck = false;
+#else  // !defined(LOGGING_IS_OFFICIAL_BUILD) && defined(NDEBUG)
+  SetMinLogLevel(LOG_FATAL + 1);
+  EXPECT_FALSE(LOG_IS_ON(FATAL));
+#endif  // !defined(LOGGING_IS_OFFICIAL_BUILD) && defined(NDEBUG)
+  DCHECK(mock_log_source.Log()) << mock_log_source.Log();
+  DPCHECK(mock_log_source.Log()) << mock_log_source.Log();
+  DCHECK_EQ(0, 0) << mock_log_source.Log();
+  DCHECK_EQ(mock_log_source.Log(), static_cast<const char*>(NULL))
+      << mock_log_source.Log();
+}
+
+TEST_F(LoggingTest, DcheckReleaseBehavior) {
+  int some_variable = 1;
+  // These should still reference |some_variable| so we don't get
+  // unused variable warnings.
+  DCHECK(some_variable) << "test";
+  DPCHECK(some_variable) << "test";
+  DCHECK_EQ(some_variable, 1) << "test";
+}
+
+}  // namespace
+
+}  // namespace logging