Paper/nms-patches/RegionFileCache.patch

--- a/net/minecraft/server/RegionFileCache.java
+++ b/net/minecraft/server/RegionFileCache.java
@@ -36,6 +36,29 @@
         }
     }
 
+    // CraftBukkit start
+    public static synchronized RegionFile b(File file, int i, int j) {
+        File file1 = new File(file, "region");
+        File file2 = new File(file1, "r." + (i >> 5) + "." + (j >> 5) + ".mca");
+        RegionFile regionfile = (RegionFile) RegionFileCache.a.get(file2);
+
+        if (regionfile != null) {
+            return regionfile;
+        } else if (file1.exists() && file2.exists()) {
+            if (RegionFileCache.a.size() >= 256) {
+                a();
+            }
+
+            RegionFile regionfile1 = new RegionFile(file2);
+
+            RegionFileCache.a.put(file2, regionfile1);
+            return regionfile1;
+        } else {
+            return null;
+        }
+    }
+    // CraftBukkit end
+
     public static synchronized void a() {
         Iterator iterator = RegionFileCache.a.values().iterator();
 
@@ -55,16 +78,32 @@
     }
 
     @Nullable
-    public static DataInputStream read(File file, int i, int j) {
+    // CraftBukkit start - call sites hoisted for synchronization
+    public static synchronized NBTTagCompound read(File file, int i, int j) throws IOException {
         RegionFile regionfile = a(file, i, j);
 
-        return regionfile.a(i & 31, j & 31);
+        DataInputStream datainputstream = regionfile.a(i & 31, j & 31);
+
+        if (datainputstream == null) {
+            return null;
+        }
+
+        return NBTCompressedStreamTools.a(datainputstream);
     }
 
     @Nullable
-    public static DataOutputStream write(File file, int i, int j) {
+    public static synchronized void write(File file, int i, int j, NBTTagCompound nbttagcompound) throws IOException {
         RegionFile regionfile = a(file, i, j);
 
-        return regionfile.c(i & 31, j & 31);
+        DataOutputStream dataoutputstream = regionfile.c(i & 31, j & 31);
+        NBTCompressedStreamTools.a(nbttagcompound, (java.io.DataOutput) dataoutputstream);
+        dataoutputstream.close();
+    }
+
+    public static synchronized boolean chunkExists(File file, int i, int j) {
+        RegionFile regionfile = b(file, i, j);
+
+        return regionfile != null ? regionfile.d(i & 31, j & 31) : false;
     }
+    // CraftBukkit end
 }