Allow multiple logging::LogMessage{Handler,Listener}s

base/test/mock_log.cc

 // 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.
 
 #include "base/test/mock_log.h"
 
 namespace base {
 namespace test {
 
 // static
 MockLog* MockLog::g_instance_ = nullptr;
 Lock MockLog::g_lock;

[Dan Beam, 2016/07/15 03:11:19]

does this class still need to stay global in nature?

[wychen, 2016/07/18 15:44:12]

Since LazyInstance is thread safe, I think we don't even need to lock.

[Dan Beam, 2016/07/18 20:00:35]

right, but this is a raw pointer, not a LazyInstance.

[wychen, 2016/07/19 18:13:06]

You are right. g_instance_ is still a raw pointer. I was referring to the
log_message_listeners behind AddLogMessageListener(), but that's not the whole
thing.

Could you clarify the first comment? Do you want to convert g_lock to an
instance variable? As long as g_instance_ is still static, I think g_lock still
need to be static.

 
 MockLog::MockLog() : is_capturing_logs_(false) {
 }
 
 MockLog::~MockLog() {
   if (is_capturing_logs_) {
     StopCapturingLogs();
   }
 }
 
 void MockLog::StartCapturingLogs() {
   AutoLock scoped_lock(g_lock);
 
   // We don't use CHECK(), which can generate a new LOG message, and
   // thus can confuse MockLog objects or other registered
   // LogSinks.
   RAW_CHECK(!is_capturing_logs_);
   RAW_CHECK(!g_instance_);
 
   is_capturing_logs_ = true;
   g_instance_ = this;
-  previous_handler_ = logging::GetLogMessageHandler();
-  logging::SetLogMessageHandler(LogMessageHandler);
+  logging::AddLogMessageListener(LogMessageListener);
 }
 
 void MockLog::StopCapturingLogs() {
   AutoLock scoped_lock(g_lock);
 
   // We don't use CHECK(), which can generate a new LOG message, and
   // thus can confuse MockLog objects or other registered
   // LogSinks.
   RAW_CHECK(is_capturing_logs_);
   RAW_CHECK(g_instance_ == this);
 
   is_capturing_logs_ = false;
-  logging::SetLogMessageHandler(previous_handler_);
+  logging::RemoveLogMessageListener(LogMessageListener);
   g_instance_ = nullptr;
 }
 
 // static
-bool MockLog::LogMessageHandler(int severity,
-                                const char* file,
-                                int line,
-                                size_t message_start,
-                                const std::string& str) {
+void MockLog::LogMessageListener(int severity,
+                                 const char* file,
+                                 int line,
+                                 size_t message_start,
+                                 const std::string& str) {
   // gMock guarantees thread-safety for calling a mocked method
   // (https://github.com/google/googlemock/blob/master/googlemock/docs/CookBook.md#using-google-mock-and-threads)
   // but we also need to make sure that Start/StopCapturingLogs are synchronized
   // with LogMessageHandler.
   AutoLock scoped_lock(g_lock);
 
   return g_instance_->Log(severity, file, line, message_start, str);
 }
 
 }  // namespace test
 }  // namespace base