logging: Add DisableLogging()

Author: ajtowns

src/bitcoin-chainstate.cpp

@@ -20,6 +20,7 @@
 
 #include <consensus/validation.h>
 #include <core_io.h>
+#include <logging.h>
 #include <node/blockstorage.h>
 #include <node/caches.h>
 #include <node/chainstate.h>
@@ -42,6 +43,12 @@
 
 int main(int argc, char* argv[])
 {
+    // We do not enable logging for this app, so explicitly disable it.
+    // To enable logging instead, replace with:
+    //    LogInstance().m_print_to_console = true;
+    //    LogInstance().StartLogging();
+    LogInstance().DisableLogging();
+
     // SETUP: Argument parsing and handling
     if (argc != 2) {
         std::cerr

src/logging.cpp

@@ -96,6 +96,18 @@ void BCLog::Logger::DisconnectTestLogger()
     m_print_callbacks.clear();
 }
 
+void BCLog::Logger::DisableLogging()
+{
+    {
+        StdLockGuard scoped_lock(m_cs);
+        assert(m_buffering);
+        assert(m_print_callbacks.empty());
+    }
+    m_print_to_file = false;
+    m_print_to_console = false;
+    StartLogging();
+}
+
 void BCLog::Logger::EnableCategory(BCLog::LogFlags flag)
 {
     m_categories |= flag;

src/logging.h

@@ -157,6 +157,14 @@ namespace BCLog {
         /** Only for testing */
         void DisconnectTestLogger() EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
 
+        /** Disable logging
+         * This offers a slight speedup and slightly smaller memory usage
+         * compared to leaving the logging system in its default state.
+         * Mostly intended for libbitcoin-kernel apps that don't want any logging.
+         * Should be used instead of StartLogging().
+         */
+        void DisableLogging() EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
+
         void ShrinkDebugFile();
 
         std::unordered_map<LogFlags, Level> CategoryLevels() const EXCLUSIVE_LOCKS_REQUIRED(!m_cs)