use the Qt logging system

Author: ifIMust

CMakeLists.txt

@@ -71,7 +71,7 @@ add_subdirectory(note)
 add_subdirectory(chord)
 add_subdirectory(settings)
 
-qt_add_executable(chordless main.cc)
+qt_add_executable(chordless main.cc logging.cpp logging.h)
 
 
 # Add QML files as resources

chord/chord_matcher_reader.cc

@@ -1,4 +1,5 @@
 #include "chord_matcher_reader.h"
+#include "../logging.h"
 
 #include "chord_matcher.h"
 #include "chord_matcher_config.h"
@@ -9,15 +10,14 @@
 
 #include <QFile>
 #include <QFileInfo>
-#include <iostream>
 #include <memory>
 
 namespace chordless::chord {
-  void configureChordObserver(ChordObserver &observer, const std::string &file_name) {
-    // Slurp the file into a string/buffer using Qt's file API (supports qrc://)
+  void ConfigureChordObserver(ChordObserver &observer, const std::string &file_name) {
+    // Load chord configuration from file (supports qrc:// resources)
     QFile file(QString::fromStdString(file_name));
     if (!file.open(QIODevice::ReadOnly)) {
-      std::cerr << "Failed to read config file\n";
+      LOG_ERROR(configCategory, "Failed to read chord config file:" << file_name);
       return;
     }
 
@@ -51,10 +51,10 @@ namespace chordless::chord {
 	  observer.AddMatcher(std::move(matcher));
 	}
       } catch (const std::exception &e) {
-	std::cerr << "Failed to parse JSON: " << e.what() << std::endl;
+        LOG_ERROR(configCategory, "Failed to parse chord configuration JSON:" << e.what());
       }
     } else {
-      std::cerr << "Failed to read file data as a string\n";
+      LOG_ERROR(configCategory, "Chord configuration file is empty");
     }
   }
 }

chord/chord_matcher_reader.h

@@ -4,6 +4,6 @@
 
 namespace chordless::chord {
   class ChordObserver;
-  
-  void configureChordObserver(ChordObserver&, const std::string &file_name);
+
+  void ConfigureChordObserver(ChordObserver&, const std::string &file_name);
 }

input/alsa/CMakeLists.txt

@@ -1,2 +1,2 @@
 add_library(alsa_input alsa_input.cc alsa_input.h ../note_input.h)
-target_link_libraries(alsa_input asound note_event)
+target_link_libraries(alsa_input PRIVATE asound note_event Qt6::Core)

input/alsa/alsa_input.cc

@@ -1,18 +1,36 @@
 #include "alsa_input.h"
+#include "../../logging.h"
 #include <utility>
 
 namespace chordless {
   namespace alsa {
     AlsaInput::AlsaInput() {
       error_ = snd_seq_open(&seq_handle_, "default", SND_SEQ_OPEN_INPUT, SND_SEQ_NONBLOCK);
-      if (error_ != 0) {
-	return;
+      if (error_ < 0) {
+        LOG_ERROR(alsaCategory, "Failed to open sequencer:" << snd_strerror(error_));
+        return;
       }
-      snd_seq_set_client_name(seq_handle_, "chordless");
 
+      // Set client name
+      int name_result = snd_seq_set_client_name(seq_handle_, "chordless");
+      if (name_result < 0) {
+        LOG_WARNING(alsaCategory, "Failed to set client name:" << snd_strerror(name_result));
+        // Continue anyway, this is not fatal
+      }
+
+      // Create port
       error_ = snd_seq_create_simple_port(seq_handle_, "Input MIDI",
-					  SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE,
-					  SND_SEQ_PORT_TYPE_MIDI_GENERIC );
+                                          SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE,
+                                          SND_SEQ_PORT_TYPE_MIDI_GENERIC);
+      if (error_ < 0) {
+        LOG_ERROR(alsaCategory, "Failed to create MIDI port:" << snd_strerror(error_));
+        snd_seq_close(seq_handle_);
+        seq_handle_ = nullptr;
+        return;
+      }
+
+      LOG_INFO(alsaCategory, "ALSA initialized successfully (client:"
+               << snd_seq_client_id(seq_handle_) << ", port:" << error_ << ")");
     }
 
     AlsaInput::~AlsaInput() {

logging.cpp

@@ -0,0 +1,7 @@
+#include "logging.h"
+
+// Define logging categories
+Q_LOGGING_CATEGORY(alsaCategory, "chordless.alsa")
+Q_LOGGING_CATEGORY(chordCategory, "chordless.chord")
+Q_LOGGING_CATEGORY(configCategory, "chordless.config")
+Q_LOGGING_CATEGORY(generalCategory, "chordless.general")

logging.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <QLoggingCategory>
+
+// Declare logging categories for different subsystems
+Q_DECLARE_LOGGING_CATEGORY(alsaCategory)
+Q_DECLARE_LOGGING_CATEGORY(chordCategory)
+Q_DECLARE_LOGGING_CATEGORY(configCategory)
+Q_DECLARE_LOGGING_CATEGORY(generalCategory)
+
+// Convenience macros for common logging patterns
+#define LOG_INFO(category, msg) qCInfo(category) << msg
+#define LOG_WARNING(category, msg) qCWarning(category) << msg
+#define LOG_ERROR(category, msg) qCCritical(category) << msg
+#define LOG_DEBUG(category, msg) qCDebug(category) << msg

main.cc

@@ -6,6 +6,7 @@
 #include "note/note_reader.h"
 #include "note/scientific_note_namer.h"
 #include "settings/settings.h"
+#include "logging.h"
 
 #include <QApplication>
 #include <QCoreApplication>
@@ -15,7 +16,6 @@
 #include <QQuickView>
 #include <QQmlEngine>
 
-#include <iostream>
 #include <memory>
 #include <string>
 #include <utility>
@@ -34,11 +34,11 @@ constexpr int chord_label_w = full_voice_label_w;
 constexpr int chord_label_h = full_voice_label_h;
 
 int main(int argc, char **argv) {
-  std::cout << "chordless v" << CHORDLESS_VERSION << std::endl;
+  LOG_INFO(generalCategory, "chordless v" << CHORDLESS_VERSION);
 
   chordless::alsa::AlsaInput alsa_input;
   if (!alsa_input.IsValid()) {
-    std::cerr << "Failed to open ALSA sequencer/port" << std::endl;
+    LOG_ERROR(alsaCategory, "Failed to open ALSA sequencer/port");
     exit(EXIT_FAILURE);
   }
 
@@ -59,7 +59,7 @@ int main(int argc, char **argv) {
     return config_result;
   }
 
-  chordless::chord::configureChordObserver(chord_observer, settings.ChordsFile());
+  chordless::chord::ConfigureChordObserver(chord_observer, settings.ChordsFile());
 
   note_reader.start();
 

settings/settings.cc

@@ -1,8 +1,8 @@
 #include "settings.h"
+#include "../logging.h"
 
 #include <boost/program_options.hpp>
 
-#include <iostream>
 #include <filesystem>
 
 namespace chordless::settings {
@@ -20,17 +20,17 @@ namespace chordless::settings {
       po::store(po::parse_command_line(argc, argv, desc), vm);
       po::notify(vm);
     } catch (...) {
-      std::cerr << desc << std::endl;
+      LOG_ERROR(configCategory, "Invalid command line options. Usage information available with --help");
       return 1;
     }
     if (vm.count("config")) {
       // User provided a config file - make it absolute for local files
       chords_file_ = std::filesystem::absolute(vm["config"].as<std::string>());
-      std::cout << "Using chord config file: " << chords_file_ << std::endl;
+      LOG_INFO(configCategory, "Using chord config file:" << chords_file_);
     } else {
       // Use embedded resource as default
       chords_file_ = ":/chords.json";
-      std::cout << "Using default chord config" << std::endl;
+      LOG_INFO(configCategory, "Using default chord config");
     }
 
     sharp_ = vm["sharp"].as<bool>();