fix: unify LogMessage and LogMessageInfo

Deprecate the custom prefix callback accepting LogMessageInfo in favor
of existing LogMessage data structure extended with necessary data
fields to avoid redundancies.

README.rst

@@ -656,32 +656,33 @@ Custom Log Prefix Format
 glog supports changing the format of the prefix attached to log messages by
 receiving a user-provided callback that generates such strings.
 
-For each log entry, the callback will be invoked with a ``LogMessageInfo``
-struct containing the severity, filename, line number, thread ID, and time of
-the event. It will also be given a reference to the output stream, whose
-contents will be prepended to the actual message in the final log line.
+For each log entry, the callback will be invoked with a reference to a
+``LogMessage`` instance containing the severity, filename, line number, thread
+ID, and time of the event. It will also be given a reference to the output
+stream, whose contents will be prepended to the actual message in the final log
+line.
 
 For example, the following function outputs a prefix that matches glog's default
 format. The third parameter ``data`` can be used to access user-supplied data
 which unless specified defaults to :cpp:`nullptr`.
 
 .. code:: cpp
 
-    void CustomPrefix(std::ostream& s, const LogMessageInfo& l, void* /*data*/) {
-       s << l.severity[0]
-       << setw(4) << 1900 + l.time.year()
-       << setw(2) << 1 + l.time.month()
-       << setw(2) << l.time.day()
+    void CustomPrefix(std::ostream& s, const LogMessage& m, void* /*data*/) {
+       s << GetLogSeverityName(m.severity())[0]
+       << setw(4) << 1900 + m.time().year()
+       << setw(2) << 1 + m.time().month()
+       << setw(2) << m.time().day()
        << ' '
-       << setw(2) << l.time.hour() << ':'
-       << setw(2) << l.time.min()  << ':'
-       << setw(2) << l.time.sec() << "."
-       << setw(6) << l.time.usec()
+       << setw(2) << m.time().hour() << ':'
+       << setw(2) << m.time().min()  << ':'
+       << setw(2) << m.time().sec() << "."
+       << setw(6) << m.time().usec()
        << ' '
        << setfill(' ') << setw(5)
-       << l.thread_id << setfill('0')
+       << m.thread_id() << setfill('0')
        << ' '
-       << l.filename << ':' << l.line_number << "]";
+       << m.basename() << ':' << m.line() << "]";
     }
 
 

src/glog/logging.h

@@ -115,7 +115,7 @@ struct GLOG_EXPORT LogMessageTime {
   std::chrono::seconds gmtoffset_;
 };
 
-struct LogMessageInfo {
+struct [[deprecated("Use LogMessage instead.")]] LogMessageInfo {
   explicit LogMessageInfo(const char* const severity_,
                           const char* const filename_, const int& line_number_,
                           std::thread::id thread_id_,
@@ -133,8 +133,28 @@ struct LogMessageInfo {
   const LogMessageTime& time;
 };
 
-typedef void (*CustomPrefixCallback)(std::ostream& s, const LogMessageInfo& l,
-                                     void* data);
+class LogMessage;
+
+#if defined(__GNUG__)
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#elif defined(_MSC_VER)
+#  pragma warning(push)
+#  pragma warning(disable : 4996)
+#endif  // __GNUG__
+using CustomPrefixCallbackV1
+    [[deprecated("Use CustomPrefixCallbackV2 instead.")]] =
+        void (*)(std::ostream&, const LogMessageInfo&, void*);
+using CustomPrefixCallback
+    [[deprecated("Use CustomPrefixCallbackV2 instead.")]] =
+        CustomPrefixCallbackV1;
+#if defined(__GNUG__)
+#  pragma GCC diagnostic pop
+#elif defined(_MSC_VER)
+#  pragma warning(pop)
+#endif  // __GNUG__
+using CustomPrefixCallbackV2 = void (*)(std::ostream&, const LogMessage&,
+                                        void*);
 
 }  // namespace google
 
@@ -485,8 +505,13 @@ namespace google {
 // specified by argv0 in log outputs.
 GLOG_EXPORT void InitGoogleLogging(const char* argv0);
 
+[[deprecated(
+    "Use InitGoogleLogging with the CustomPrefixCallbackV2 overload "
+    "instead.")]] GLOG_EXPORT void
+InitGoogleLogging(const char* argv0, CustomPrefixCallbackV1 prefix_callback,
+                  void* prefix_callback_data = nullptr);
 GLOG_EXPORT void InitGoogleLogging(const char* argv0,
-                                   CustomPrefixCallback prefix_callback,
+                                   CustomPrefixCallbackV2 prefix_callback,
                                    void* prefix_callback_data = nullptr);
 
 // Check if google's logging library has been initialized.
@@ -1343,9 +1368,15 @@ class GLOG_EXPORT LogMessage {
     return time();
   }
 
-  const LogMessageTime& time() const;
+  LogSeverity severity() const noexcept;
+  int line() const noexcept;
+  const std::thread::id& thread_id() const noexcept;
+  const char* fullname() const noexcept;
+  const char* basename() const noexcept;
+  const LogMessageTime& time() const noexcept;
 
-  struct LogMessageData;
+  LogMessage(const LogMessage&) = delete;
+  LogMessage& operator=(const LogMessage&) = delete;
 
  private:
   // Fully internal SendMethod cases:
@@ -1373,9 +1404,6 @@ class GLOG_EXPORT LogMessage {
   LogMessageTime time_;
 
   friend class LogDestination;
-
-  LogMessage(const LogMessage&);
-  void operator=(const LogMessage&);
 };
 
 // This class happens to be thread-hostile because all instances share
@@ -1493,7 +1521,7 @@ class GLOG_EXPORT LogSink {
   // during this call.
   virtual void send(LogSeverity severity, const char* full_filename,
                     const char* base_filename, int line,
-                    const LogMessageTime& logmsgtime, const char* message,
+                    const LogMessageTime& time, const char* message,
                     size_t message_len);
   // Provide an overload for compatibility purposes
   GLOG_DEPRECATED
@@ -1519,8 +1547,8 @@ class GLOG_EXPORT LogSink {
   // Returns the normal text output of the log message.
   // Can be useful to implement send().
   static std::string ToString(LogSeverity severity, const char* file, int line,
-                              const LogMessageTime& logmsgtime,
-                              const char* message, size_t message_len);
+                              const LogMessageTime& time, const char* message,
+                              size_t message_len);
 };
 
 // Add or remove a LogSink as a consumer of logging data.  Thread-safe.