util: Establish global logger object.

The object encapsulates logging configuration, and in a later commit,
set up routines will also be moved into the class.

src/bench/bench_bitcoin.cpp

@@ -46,7 +46,7 @@ main(int argc, char** argv)
     RandomInit();
     ECC_Start();
     SetupEnvironment();
-    fPrintToDebugLog = false; // don't want to write to debug.log file
+    g_logger->fPrintToDebugLog = false; // don't want to write to debug.log file
 
     int64_t evaluations = gArgs.GetArg("-evals", DEFAULT_BENCH_EVALUATIONS);
     std::string regex_filter = gArgs.GetArg("-filter", DEFAULT_BENCH_FILTER);

src/init.cpp

@@ -305,7 +305,7 @@ static void HandleSIGTERM(int)
 
 static void HandleSIGHUP(int)
 {
-    fReopenDebugLog = true;
+    g_logger->fReopenDebugLog = true;
 }
 
 #ifndef WIN32
@@ -831,10 +831,11 @@ void InitLogging()
     // debug.log.
     LogPrintf("\n\n\n\n\n");
 
-    fPrintToConsole = gArgs.GetBoolArg("-printtoconsole", !gArgs.GetBoolArg("-daemon", false));
+    g_logger->fPrintToConsole = gArgs.GetBoolArg("-printtoconsole", !gArgs.GetBoolArg("-daemon", false));
-    fPrintToDebugLog = !gArgs.IsArgNegated("-debuglogfile");
+    g_logger->fPrintToDebugLog = !gArgs.IsArgNegated("-debuglogfile");
-    fLogTimestamps = gArgs.GetBoolArg("-logtimestamps", DEFAULT_LOGTIMESTAMPS);
+    g_logger->fLogTimestamps = gArgs.GetBoolArg("-logtimestamps", DEFAULT_LOGTIMESTAMPS);
-    fLogTimeMicros = gArgs.GetBoolArg("-logtimemicros", DEFAULT_LOGTIMEMICROS);
+    g_logger->fLogTimeMicros = gArgs.GetBoolArg("-logtimemicros", DEFAULT_LOGTIMEMICROS);
+
     fLogIPs = gArgs.GetBoolArg("-logips", DEFAULT_LOGIPS);
 
     std::string version_string = FormatFullVersion();
@@ -1230,7 +1231,7 @@ bool AppInitMain()
 #ifndef WIN32
     CreatePidFile(GetPidFile(), getpid());
 #endif
-    if (fPrintToDebugLog) {
+    if (g_logger->fPrintToDebugLog) {
         if (gArgs.GetBoolArg("-shrinkdebugfile", logCategories == BCLog::NONE)) {
             // Do this first since it both loads a bunch of debug.log into memory,
             // and because this needs to happen before any other debug.log printing
@@ -1241,7 +1242,7 @@ bool AppInitMain()
         }
     }
 
-    if (!fLogTimestamps)
+    if (!g_logger->fLogTimestamps)
         LogPrintf("Startup time: %s\n", FormatISO8601DateTime(GetTime()));
     LogPrintf("Default data directory %s\n", GetDefaultDataDir().string());
     LogPrintf("Using data directory %s\n", GetDataDir().string());

src/logging.cpp

@@ -12,13 +12,22 @@
 
 const char * const DEFAULT_DEBUGLOGFILE = "debug.log";
 
-bool fPrintToConsole = false;
+/**
-bool fPrintToDebugLog = true;
+ * NOTE: the logger instances is leaked on exit. This is ugly, but will be
+ * cleaned up by the OS/libc. Defining a logger as a global object doesn't work
+ * since the order of destruction of static/global objects is undefined.
+ * Consider if the logger gets destroyed, and then some later destructor calls
+ * LogPrintf, maybe indirectly, and you get a core dump at shutdown trying to
+ * access the logger. When the shutdown sequence is fully audited and tested,
+ * explicit destruction of these objects can be implemented by changing this
+ * from a raw pointer to a std::unique_ptr.
+ *
+ * This method of initialization was originally introduced in
+ * ee3374234c60aba2cc4c5cd5cac1c0aefc2d817c.
+ */
+BCLog::Logger* const g_logger = new BCLog::Logger();
 
-bool fLogTimestamps = DEFAULT_LOGTIMESTAMPS;
-bool fLogTimeMicros = DEFAULT_LOGTIMEMICROS;
 bool fLogIPs = DEFAULT_LOGIPS;
-std::atomic<bool> fReopenDebugLog(false);
 
 /** Log categories bitfield. */
 std::atomic<uint32_t> logCategories(0);
@@ -174,19 +183,14 @@ std::vector<CLogCategoryActive> ListActiveLogCategories()
     return ret;
 }
 
-/**
+std::string BCLog::Logger::LogTimestampStr(const std::string &str)
- * fStartedNewLine is a state variable held by the calling context that will
- * suppress printing of the timestamp when multiple calls are made that don't
- * end in a newline. Initialize it to true, and hold it, in the calling context.
- */
-static std::string LogTimestampStr(const std::string &str, std::atomic_bool *fStartedNewLine)
 {
     std::string strStamped;
 
     if (!fLogTimestamps)
         return str;
 
-    if (*fStartedNewLine) {
+    if (fStartedNewLine) {
         int64_t nTimeMicros = GetTimeMicros();
         strStamped = FormatISO8601DateTime(nTimeMicros/1000000);
         if (fLogTimeMicros) {
@@ -202,19 +206,18 @@ static std::string LogTimestampStr(const std::string &str, std::atomic_bool *fSt
         strStamped = str;
 
     if (!str.empty() && str[str.size()-1] == '\n')
-        *fStartedNewLine = true;
+        fStartedNewLine = true;
     else
-        *fStartedNewLine = false;
+        fStartedNewLine = false;
 
     return strStamped;
 }
 
-int LogPrintStr(const std::string &str)
+int BCLog::Logger::LogPrintStr(const std::string &str)
 {
     int ret = 0; // Returns total number of characters written
-    static std::atomic_bool fStartedNewLine(true);
 
-    std::string strTimestamped = LogTimestampStr(str, &fStartedNewLine);
+    std::string strTimestamped = LogTimestampStr(str);
 
     if (fPrintToConsole) {
         // print to console

src/logging.h

@@ -19,13 +19,7 @@ static const bool DEFAULT_LOGIPS        = false;
 static const bool DEFAULT_LOGTIMESTAMPS = true;
 extern const char * const DEFAULT_DEBUGLOGFILE;
 
-extern bool fPrintToConsole;
-extern bool fPrintToDebugLog;
-
-extern bool fLogTimestamps;
-extern bool fLogTimeMicros;
 extern bool fLogIPs;
-extern std::atomic<bool> fReopenDebugLog;
 
 extern std::atomic<uint32_t> logCategories;
 
@@ -61,7 +55,39 @@ namespace BCLog {
         LEVELDB     = (1 << 20),
         ALL         = ~(uint32_t)0,
     };
-}
+
+    class Logger
+    {
+    private:
+        /**
+         * fStartedNewLine is a state variable that will suppress printing of
+         * the timestamp when multiple calls are made that don't end in a
+         * newline.
+         */
+        std::atomic_bool fStartedNewLine{true};
+
+        std::string LogTimestampStr(const std::string& str);
+
+    public:
+        bool fPrintToConsole = false;
+        bool fPrintToDebugLog = true;
+
+        bool fLogTimestamps = DEFAULT_LOGTIMESTAMPS;
+        bool fLogTimeMicros = DEFAULT_LOGTIMEMICROS;
+
+        std::atomic<bool> fReopenDebugLog{false};
+
+        /** Send a string to the log output */
+        int LogPrintStr(const std::string &str);
+
+        /** Returns whether logs will be written to any output */
+        bool Enabled() const { return fPrintToConsole || fPrintToDebugLog; }
+    };
+
+} // namespace BCLog
+
+extern BCLog::Logger* const g_logger;
+
 /** Return true if log accepts specified category */
 static inline bool LogAcceptCategory(uint32_t category)
 {
@@ -77,9 +103,6 @@ std::vector<CLogCategoryActive> ListActiveLogCategories();
 /** Return true if str parses as a log category and set the flags in f */
 bool GetLogCategory(uint32_t *f, const std::string *str);
 
-/** Send a string to the log output */
-int LogPrintStr(const std::string &str);
-
 /** Get format string from VA_ARGS for error reporting */
 template<typename... Args> std::string FormatStringFromLogArgs(const char *fmt, const Args&... args) { return fmt; }
 
@@ -99,7 +122,7 @@ template<typename T, typename... Args> static inline void MarkUsed(const T& t, c
 #define LogPrint(category, ...) do { MarkUsed(__VA_ARGS__); } while(0)
 #else
 #define LogPrintf(...) do { \
-    if (fPrintToConsole || fPrintToDebugLog) { \
+    if (g_logger->Enabled()) { \
         std::string _log_msg_; /* Unlikely name to avoid shadowing variables */ \
         try { \
             _log_msg_ = tfm::format(__VA_ARGS__); \
@@ -107,7 +130,7 @@ template<typename T, typename... Args> static inline void MarkUsed(const T& t, c
             /* Original format string will have newline so don't add one here */ \
             _log_msg_ = "Error \"" + std::string(fmterr.what()) + "\" while formatting log message: " + FormatStringFromLogArgs(__VA_ARGS__); \
         } \
-        LogPrintStr(_log_msg_); \
+        g_logger->LogPrintStr(_log_msg_); \
     } \
 } while(0)
 

src/test/test_bitcoin.cpp

@@ -47,7 +47,7 @@ BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
         SetupNetworking();
         InitSignatureCache();
         InitScriptExecutionCache();
-        fPrintToDebugLog = false; // don't want to write to debug.log file
+        g_logger->fPrintToDebugLog = false; // don't want to write to debug.log file
         fCheckBlockIndex = true;
         SelectParams(chainName);
         noui_connect();

src/util.h

@@ -66,7 +66,7 @@ bool SetupNetworking();
 template<typename... Args>
 bool error(const char* fmt, const Args&... args)
 {
-    LogPrintStr("ERROR: " + tfm::format(fmt, args...) + "\n");
+    LogPrintf("ERROR: %s\n", tfm::format(fmt, args...));
     return false;
 }