Tentative fix for #24

Author: TBlueF

BlueMapCore/src/main/java/de/bluecolored/bluemap/core/mca/MCAWorld.java

@@ -218,40 +218,57 @@ private Chunk loadChunk(Vector2i chunkPos) throws IOException {
 		Vector2i regionPos = chunkToRegion(chunkPos);
 		Path regionPath = getMCAFilePath(regionPos);
 
-		try (RandomAccessFile raf = new RandomAccessFile(regionPath.toFile(), "r")) {
+		Throwable exception = null;
 
-			int xzChunk = Math.floorMod(chunkPos.getY(), 32) * 32 + Math.floorMod(chunkPos.getX(), 32);
-			
-			raf.seek(xzChunk * 4);
-			int offset = raf.read() << 16;
-			offset |= (raf.read() & 0xFF) << 8;
-			offset |= raf.read() & 0xFF;
-			offset *= 4096;
-			
-			int size = raf.readByte() * 4096;
-			if (size == 0) {
-				return Chunk.empty(this, chunkPos);
+		for (int tries = 1; tries <= 5; tries++) {
+			if (tries > 1) {
+				try {
+					Thread.sleep(200);
+				} catch (InterruptedException interrupt) {
+					throw new IOException("Interrupted while waiting for the " + tries + "th try to load a chunk..");
+				}
 			}
 
-			raf.seek(offset + 4); // +4 skip chunk size
+			try (RandomAccessFile raf = new RandomAccessFile(regionPath.toFile(), "r")) {
 
-			byte compressionTypeByte = raf.readByte();
-			CompressionType compressionType = CompressionType.getFromID(compressionTypeByte);
-			if (compressionType == null) {
-				throw new IOException("invalid compression type " + compressionTypeByte);
-			}
-			
-			DataInputStream dis = new DataInputStream(new BufferedInputStream(compressionType.decompress(new FileInputStream(raf.getFD()))));
-			Tag<?> tag = Tag.deserialize(dis, Tag.DEFAULT_MAX_DEPTH);
-			if (tag instanceof CompoundTag) {
-				return Chunk.create(this, (CompoundTag) tag);
-			} else {
-				throw new IOException("invalid data tag: " + (tag == null ? "null" : tag.getClass().getName()));
+				int xzChunk = Math.floorMod(chunkPos.getY(), 32) * 32 + Math.floorMod(chunkPos.getX(), 32);
+				
+				raf.seek(xzChunk * 4);
+				int offset = raf.read() << 16;
+				offset |= (raf.read() & 0xFF) << 8;
+				offset |= raf.read() & 0xFF;
+				offset *= 4096;
+				
+				int size = raf.readByte() * 4096;
+				if (size == 0) {
+					return Chunk.empty(this, chunkPos);
+				}
+				
+				raf.seek(offset + 4); // +4 skip chunk size
+				
+				byte compressionTypeByte = raf.readByte();
+				CompressionType compressionType = CompressionType.getFromID(compressionTypeByte);
+				if (compressionType == null) {
+					throw new IOException("invalid compression type " + compressionTypeByte);
+				}
+				
+				DataInputStream dis = new DataInputStream(new BufferedInputStream(compressionType.decompress(new FileInputStream(raf.getFD()))));
+				Tag<?> tag = Tag.deserialize(dis, Tag.DEFAULT_MAX_DEPTH);
+				if (tag instanceof CompoundTag) {
+					return Chunk.create(this, (CompoundTag) tag);
+				} else {
+					throw new IOException("invalid data tag: " + (tag == null ? "null" : tag.getClass().getName()));
+				}
+				
+			} catch (FileNotFoundException ex) {
+				return Chunk.empty(this, chunkPos);
+			} catch (Throwable ex) {
+				exception = ex;
 			}
-			
-		} catch (FileNotFoundException ex) {
-			return Chunk.empty(this, chunkPos);
 		}
+		
+		if (exception == null) throw new IOException("Failed to load chunk after multiple attempts!");
+		throw new IOException("Failed to load chunk after multiple attempts!", exception);
 	}
 
 	@Override