Fix not showing early logged messages in the UI (#1712)

* Buffer log events before a receiver is set, fixes #1702

* Always set a receiver if an unchecked exception was thrown when running chunky

chunky/src/java/se/llbit/chunky/main/Chunky.java

@@ -44,6 +44,7 @@
 import se.llbit.chunky.world.MaterialStore;
 import se.llbit.json.JsonArray;
 import se.llbit.json.JsonValue;
+import se.llbit.log.ConsoleReceiver;
 import se.llbit.log.Level;
 import se.llbit.log.Log;
 import se.llbit.log.Receiver;
@@ -237,6 +238,8 @@ public static void main(final String[] args) {
             break;
         }
       } catch (Throwable t) {
+        // set receiver in case an exception was thrown before it was set in one of the start modes.
+        Log.setReceiver(ConsoleReceiver.INSTANCE, Level.INFO, Level.WARNING, Level.ERROR);
         Log.error("Unchecked exception caused Chunky to close.", t);
         exitCode = 2;
       }

lib/src/se/llbit/log/BufferingConsoleReceiver.java

@@ -0,0 +1,28 @@
+package se.llbit.log;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class BufferingConsoleReceiver extends Receiver {
+  public static final BufferingConsoleReceiver INSTANCE = new BufferingConsoleReceiver();
+
+  private final List<Event> bufferedEvents = new ArrayList<>();
+
+  protected BufferingConsoleReceiver() {
+  }
+
+  @Override
+  public void logEvent(Level level, String message) {
+    this.bufferedEvents.add(new Event(level, message));
+  }
+
+  @Override
+  public boolean isBuffered() {
+    return true;
+  }
+
+  @Override
+  public List<Event> getBufferedEvents() {
+    return this.bufferedEvents;
+  }
+}

lib/src/se/llbit/log/Log.java

@@ -29,7 +29,7 @@ public class Log {
   private static final int WARNING = Level.WARNING.ordinal();
   private static final int ERROR = Level.ERROR.ordinal();
   private static final Receiver[] receiver =
-      {ConsoleReceiver.INSTANCE, ConsoleReceiver.INSTANCE, ConsoleReceiver.INSTANCE};
+      {BufferingConsoleReceiver.INSTANCE, BufferingConsoleReceiver.INSTANCE, BufferingConsoleReceiver.INSTANCE};
 
   static {
     try {
@@ -51,7 +51,15 @@ public static void setReceiver(Receiver receiver, Level... levels) {
       throw new IllegalArgumentException("No log level specified for receiver.");
     }
     for (Level level : levels) {
+      Receiver previousReceiver = Log.receiver[level.ordinal()];
       Log.receiver[level.ordinal()] = receiver;
+
+      // flush the buffered receiver, if required.
+      if (previousReceiver.isBuffered()) {
+        previousReceiver.getBufferedEvents().stream()
+          .filter(event -> event.level == level)
+          .forEach(event -> receiver.logEvent(event.level, event.message));
+      }
     }
   }
 

lib/src/se/llbit/log/Receiver.java

@@ -18,6 +18,8 @@
 
 import java.io.PrintWriter;
 import java.io.StringWriter;
+import java.util.Collections;
+import java.util.List;
 
 abstract public class Receiver {
   abstract public void logEvent(Level level, String message);
@@ -37,4 +39,21 @@ public void logEvent(Level level, Throwable thrown) {
     logEvent(level, writer.toString());
   }
 
+  public boolean isBuffered() {
+    return false;
+  }
+
+  public List<Event> getBufferedEvents() {
+    return Collections.emptyList();
+  }
+
+  public static class Event {
+    public final Level level;
+    public final String message;
+
+      public Event(Level level, String message) {
+        this.level = level;
+        this.message = message;
+      }
+  }
 }