Restore util::NullLogger rather than duplicating it each place it's used

Author: tgoyne

src/realm/util/logger.hpp

@@ -497,6 +497,12 @@ class LocalThresholdLogger : public Logger {
     std::shared_ptr<Logger> m_chained_logger;
 };
 
+/// A logger that performs a noop when logging functions are called
+class NullLogger : public Logger {
+    // Since we don't want to log anything, do_log() does nothing
+    void do_log(const LogCategory&, Level, const std::string&) override {}
+};
+
 
 // Implementation
 

test/object-store/audit.cpp

@@ -52,18 +52,11 @@ using namespace std::string_literals;
 using Catch::Matchers::StartsWith;
 using nlohmann::json;
 
-namespace {
-class NullLogger : public util::Logger {
-    // Since we don't want to log anything, do_log() does nothing
-    void do_log(const util::LogCategory&, Level, const std::string&) override {}
-};
-} // namespace
-
 static auto audit_logger =
 #ifdef AUDIT_LOG_LEVEL
     std::make_shared<util::StderrLogger>(AUDIT_LOG_LEVEL);
 #else
-    std::make_shared<NullLogger>();
+    std::make_shared<util::NullLogger>();
 #endif
 
 namespace {

test/object-store/benchmarks/client_reset.cpp

@@ -139,10 +139,7 @@ struct BenchmarkLocalClientReset : public reset_utils::TestClientReset {
         Transaction& wt_local = (Transaction&)m_local->read_group();
         VersionID current_local_version = wt_local.get_version_of_current_transaction();
 
-        class NullLogger : public util::Logger {
-            // Since we don't want to log anything, do_log() does nothing
-            void do_log(const util::LogCategory&, Level, const std::string&) override {}
-        } logger;
+        util::NullLogger logger;
 
         if (m_mode == ClientResyncMode::Recover) {
             auto history_local = dynamic_cast<sync::ClientHistory*>(wt_local.get_replication()->_get_history_write());

test/test_client_reset.cpp

@@ -1477,13 +1477,6 @@ TEST(ClientReset_Recover_RecoverableChangesOnListsAfterUnrecoverableAreNotDuplic
     CHECK_EQUAL(changes.size(), 1);
 }
 
-namespace {
-class NullLogger : public util::Logger {
-    // Since we don't want to log anything, do_log() does nothing
-    void do_log(const util::LogCategory&, Level, const std::string&) override {}
-};
-} // namespace
-
 // Apply uploaded changes in src to dst as if they had been exchanged by sync
 void apply_changes(DB& src, DB& dst)
 {
@@ -1515,7 +1508,7 @@ void apply_changes(DB& src, DB& dst)
     dst_progress.download.server_version += remote_changesets.size();
     dst_progress.latest_server_version.version += remote_changesets.size();
 
-    NullLogger logger;
+    util::NullLogger logger;
     VersionInfo new_version;
     dst_history.integrate_server_changesets(dst_progress, nullptr, remote_changesets, new_version,
                                             DownloadBatchState::SteadyState, logger, dst.start_read());