srslog: pass log_label as shared_ptr

Author: robertfalkenberg

include/srsran/srslog/detail/log_entry_metadata.h

@@ -34,7 +34,7 @@ struct log_entry_metadata {
   fmt::dynamic_format_arg_store<fmt::format_context>* store;
   std::string                                         log_name;
   char                                                log_tag;
-  std::string                                         log_label;
+  std::shared_ptr<const std::string>                  log_label;
   std::vector<uint8_t>                                hex_dump;
 };
 

include/srsran/srslog/log_channel.h

@@ -44,13 +44,6 @@ struct log_channel_config {
   bool should_print_context = false;
 };
 
-/// Strong type to wrap a constant log label that is prepended to each log message.
-struct log_label_t {
-  /// Optional log label. If set, will get printed in front of each log message.
-  /// Disabled by default.
-  std::string log_label;
-};
-
 /// A log channel is the entity used for logging messages.
 ///
 /// It can deliver a log entry to one or more different sinks, for example a
@@ -146,7 +139,7 @@ class log_channel
   /// Builds the provided log entry and passes it to the backend. When the
   /// channel is disabled the log entry will be discarded.
   template <typename... Args>
-  void operator()(const log_label_t& label, const char* fmtstr, Args&&... args)
+  void operator()(std::shared_ptr<const std::string> log_label, const char* fmtstr, Args&&... args)
   {
     if (!enabled()) {
       return;
@@ -171,7 +164,7 @@ class log_channel
                                     store,
                                     log_name,
                                     log_tag,
-                                    label.log_label}};
+                                    std::move(log_label)}};
     backend.push(std::move(entry));
   }
 
@@ -247,7 +240,11 @@ class log_channel
   /// Builds the provided log entry and passes it to the backend. When the
   /// channel is disabled the log entry will be discarded.
   template <typename... Args>
-  void operator()(const log_label_t& label, const uint8_t* buffer, size_t len, const char* fmtstr, Args&&... args)
+  void operator()(std::shared_ptr<const std::string> log_label,
+                  const uint8_t*                     buffer,
+                  size_t                             len,
+                  const char*                        fmtstr,
+                  Args&&... args)
   {
     if (!enabled()) {
       return;
@@ -277,7 +274,7 @@ class log_channel
                                     store,
                                     log_name,
                                     log_tag,
-                                    label.log_label,
+                                    std::move(log_label),
                                     std::vector<uint8_t>(buffer, buffer + len)}};
     backend.push(std::move(entry));
   }
@@ -361,7 +358,8 @@ class log_channel
   /// Builds the provided log entry and passes it to the backend. When the
   /// channel is disabled the log entry will be discarded.
   template <typename It, typename... Args, typename std::enable_if<detail::is_byte_iterable<It>::value, int>::type = 0>
-  void operator()(const log_label_t& label, It it_begin, It it_end, const char* fmtstr, Args&&... args)
+  void
+  operator()(std::shared_ptr<const std::string> log_label, It it_begin, It it_end, const char* fmtstr, Args&&... args)
   {
     if (!enabled()) {
       return;
@@ -391,7 +389,7 @@ class log_channel
                                     store,
                                     log_name,
                                     log_tag,
-                                    label.log_label,
+                                    std::move(log_label),
                                     std::vector<uint8_t>(it_begin, it_end)}};
     backend.push(std::move(entry));
   }

include/srsran/support/prefixed_logger.h

@@ -35,7 +35,7 @@ class prefixed_logger
   {
     fmt::memory_buffer buffer;
     fmt::format_to(buffer, "{}{}", prefix, prefix_separator);
-    log_label.log_label = fmt::to_string(buffer);
+    log_label = std::make_shared<const std::string>(fmt::to_string(buffer));
   }
 
   template <typename... Args>
@@ -199,8 +199,8 @@ class prefixed_logger
   srslog::basic_logger& get_basic_logger() { return logger; }
 
 private:
-  srslog::basic_logger& logger;
-  srslog::log_label_t   log_label;
+  srslog::basic_logger&              logger;
+  std::shared_ptr<const std::string> log_label;
 
   template <typename... Args>
   void log_helper(srslog::log_channel& channel, const char* fmt, Args&&... args) const

lib/srslog/formatters/text_formatter.cpp

@@ -61,8 +61,8 @@ static void format_metadata(const detail::log_entry_metadata& metadata, fmt::mem
     ctx_buffer.push_back('\0');
     fmt::format_to(buffer, "[{: >8}] ", ctx_buffer.data());
   }
-  if (!metadata.log_label.empty()) {
-    fmt::format_to(buffer, "{}", metadata.log_label);
+  if (metadata.log_label != nullptr && !metadata.log_label->empty()) {
+    fmt::format_to(buffer, "{}", *metadata.log_label);
   }
 }