Add primitive logging mechanism

source/app/CMakeLists.txt

@@ -6,6 +6,7 @@ set( srcs
     clipboard.cpp
     command.cpp
     documentmanager.cpp
+    log.cpp
     paths.cpp
     powertabeditor.cpp
     recentfiles.cpp
@@ -22,6 +23,7 @@ set( headers
     clipboard.h
     command.h
     documentmanager.h
+    log.h
     paths.h
     powertabeditor.h
     recentfiles.h

source/app/log.cpp

@@ -0,0 +1,88 @@
+/*
+  * Copyright (C) 2021 Simon Symeonidis
+  *
+  * This program is free software: you can redistribute it and/or modify
+  * it under the terms of the GNU General Public License as published by
+  * the Free Software Foundation, either version 3 of the License, or
+  * (at your option) any later version.
+  *
+  * This program is distributed in the hope that it will be useful,
+  * but WITHOUT ANY WARRANTY; without even the implied warranty of
+  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  * GNU General Public License for more details.
+  *
+  * You should have received a copy of the GNU General Public License
+  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include "log.h"
+#include "paths.h"
+
+#include <cstdio>
+#include <ctime>
+#include <fstream>
+#include <sstream>
+#include <iostream>
+
+namespace Log {
+// destructor should close the file when main exits
+// note: might not capture critical errors, but this should be a good
+// enought start...
+std::ofstream logFile(Paths::getLogPath().string(),
+                      std::ofstream::out);
+
+void Output(QtMsgType type, const QMessageLogContext &context, const QString &msg)
+{
+    QByteArray localMsg = msg.toLocal8Bit();
+    const char *file = context.file ? context.file : "";
+    const char *function = context.function ? context.function : "";
+
+    std::string timestamp;
+    {
+        char output[128] = {0};
+        const auto now = std::time(0);
+        const auto *tmp = localtime(&now);
+        strftime(output, sizeof(output), "%Y/%m/%dT%H:%M:%S", tmp);
+        timestamp = std::string(output);
+    }
+
+    auto logFn = [&](std::string label,
+                     std::ostream& ofile,
+                     std::ostream& oterminal)-> void
+    {
+        // std::format when? :(
+        ofile
+            << timestamp << " "
+            << label << ": "
+            << localMsg.constData() << " "
+            << file << " "
+            << context.line << " "
+            << function << std::endl;
+
+        oterminal
+            << timestamp << " "
+            << label << ": "
+            << localMsg.constData() << " "
+            << file << " "
+            << context.line << " "
+            << function << std::endl;
+    };
+
+    switch (type) {
+    case QtDebugMsg:
+        logFn("debug", logFile, std::cerr);
+        break;
+    case QtInfoMsg:
+        logFn("debug", logFile, std::cerr);
+        break;
+    case QtWarningMsg:
+        logFn("warning", logFile, std::cerr);
+        break;
+    case QtCriticalMsg:
+        logFn("critical", logFile, std::cerr);
+        break;
+    case QtFatalMsg:
+        logFn("fatal", logFile, std::cerr);
+        break;
+    }
+}
+}

source/app/log.h

@@ -0,0 +1,26 @@
+/*
+  * Copyright (C) 2021 Simon Symeonidis
+  *
+  * This program is free software: you can redistribute it and/or modify
+  * it under the terms of the GNU General Public License as published by
+  * the Free Software Foundation, either version 3 of the License, or
+  * (at your option) any later version.
+  *
+  * This program is distributed in the hope that it will be useful,
+  * but WITHOUT ANY WARRANTY; without even the implied warranty of
+  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  * GNU General Public License for more details.
+  *
+  * You should have received a copy of the GNU General Public License
+  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#ifndef APP_LOG_H
+#define APP_LOG_H
+
+#include <QString>
+#include <QtGlobal>
+
+namespace Log {
+void Output(QtMsgType type, const QMessageLogContext &context, const QString &msg);
+}
+#endif

source/app/paths.cpp

@@ -37,6 +37,11 @@ path getConfigDir()
 #endif
 }
 
+path getLogPath()
+{
+    return getConfigDir() / "log.txt";
+}
+
 path getUserDataDir()
 {
     return fromQString(

source/app/paths.h

@@ -26,6 +26,9 @@ namespace Paths {
     /// Return a path to a directory where config files should be written to.
     path getConfigDir();
 
+    /// Return a path to the log file
+    path getLogPath();
+
     /// Return a path to a directory where persistent application data should
     /// be written to.
     path getUserDataDir();

source/build/main.cpp

@@ -14,8 +14,9 @@
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
- 
+
 #include <app/appinfo.h>
+#include <app/log.h>
 #include <app/paths.h>
 #include <app/powertabeditor.h>
 #include <app/settings.h>
@@ -130,6 +131,8 @@ class Application : public QApplication
 
 int main(int argc, char *argv[])
 {
+    qInstallMessageHandler(Log::Output);
+
     // Register handlers for unhandled exceptions and segmentation faults.
     std::set_terminate(terminateHandler);
     std::signal(SIGSEGV, signalHandler);