From 1de301752f74e153b18228097708f010877e65cb Mon Sep 17 00:00:00 2001
From: flow <flowlnlnln@gmail.com>
Date: Sat, 24 Dec 2022 03:58:49 -0800
Subject: [PATCH] Merge pull request #665 from flowln/logging_categories

---
 launcher/Application.cpp         | 23 ++++++++++++-----------
 program_info/prismlauncher.6.scd | 18 ++++++++++++++++++
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/launcher/Application.cpp b/launcher/Application.cpp
index 3f313ee4a..ff34a168d 100644
--- a/launcher/Application.cpp
+++ b/launcher/Application.cpp
@@ -146,19 +146,12 @@ static const QLatin1String liveCheckFile("live.check");
 PixmapCache* PixmapCache::s_instance = nullptr;
 
 namespace {
+
+/** This is used so that we can output to the log file in addition to the CLI. */
 void appDebugOutput(QtMsgType type, const QMessageLogContext &context, const QString &msg)
 {
-    const char *levels = "DWCFIS";
-    const QString format("%1 %2 %3\n");
-
-    qint64 msecstotal = APPLICATION->timeSinceStart();
-    qint64 seconds = msecstotal / 1000;
-    qint64 msecs = msecstotal % 1000;
-    QString foo;
-    char buf[1025] = {0};
-    ::snprintf(buf, 1024, "%5lld.%03lld", seconds, msecs);
-
-    QString out = format.arg(buf).arg(levels[type]).arg(msg);
+    QString out = qFormatLogMessage(type, context, msg);
+    out += QChar::LineFeed;
 
     APPLICATION->logFile->write(out.toUtf8());
     APPLICATION->logFile->flush();
@@ -431,6 +424,14 @@ Application::Application(int &argc, char **argv) : QApplication(argc, argv)
             return;
         }
         qInstallMessageHandler(appDebugOutput);
+
+        qSetMessagePattern(
+                "%{time process}" " "
+                "%{if-debug}D%{endif}" "%{if-info}I%{endif}" "%{if-warning}W%{endif}" "%{if-critical}C%{endif}" "%{if-fatal}F%{endif}"
+                " " "|" " "
+                "%{if-category}[%{category}]: %{endif}"
+                "%{message}");
+
         qDebug() << "<> Log initialized.";
     }
 
diff --git a/program_info/prismlauncher.6.scd b/program_info/prismlauncher.6.scd
index f979e4571..e1ebfff32 100644
--- a/program_info/prismlauncher.6.scd
+++ b/program_info/prismlauncher.6.scd
@@ -41,6 +41,24 @@ Here are the current features of Prism Launcher.
 *-a, --profile*=PROFILE
 	Use the account specified by PROFILE (only valid in combination with --launch).
 
+# ENVIRONMENT
+
+The behavior of the launcher can be customized by the following environment
+variables, besides other common Qt variables:
+
+*QT_LOGGING_RULES*
+	Specifies which logging categories are shown in the logs. One can
+	enable/disable multiple categories by separating them with a semicolon (;).
+
+	The specific syntax, and alternatives to this setting, can be found at
+	https://doc.qt.io/qt-6/qloggingcategory.html#configuring-categories.
+
+*QT_MESSAGE_PATTERN*
+	Specifies the format in which the console output will be shown.
+
+	Available options, as well as syntax, can be viewed at
+	https://doc.qt.io/qt-6/qtglobal.html#qSetMessagePattern.
+
 # EXIT STATUS
 
 *0*