Import necessary nms

sources/src/main/java/net/minecraft/server/RegionFileCache.java

@@ -0,0 +1,124 @@
+package net.minecraft.server;
+
+import com.destroystokyo.paper.exception.ServerInternalException;
+import com.google.common.collect.Maps;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.Map;
+import com.destroystokyo.paper.PaperConfig; // Paper
+import java.util.LinkedHashMap; // Paper
+
+public class RegionFileCache {
+
+    public static final Map<File, RegionFile> a = new LinkedHashMap(PaperConfig.regionFileCacheSize, 0.75f, true); // Spigot - private -> public, Paper - HashMap -> LinkedHashMap
+
+    public static synchronized RegionFile a(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()) {
+                file1.mkdirs();
+            }
+
+            if (RegionFileCache.a.size() >= PaperConfig.regionFileCacheSize) { // Paper
+                trimCache(); // Paper
+            }
+
+            RegionFile regionfile1 = new RegionFile(file2);
+
+            RegionFileCache.a.put(file2, regionfile1);
+            return regionfile1;
+        }
+    }
+
+    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;
+        }
+    }
+
+    // Paper Start
+    private static synchronized void trimCache() {
+        Iterator<Map.Entry<File, RegionFile>> itr = RegionFileCache.a.entrySet().iterator();
+        int count = RegionFileCache.a.size() - PaperConfig.regionFileCacheSize;
+        while (count-- >= 0 && itr.hasNext()) {
+            try {
+                itr.next().getValue().c();
+            } catch (IOException ioexception) {
+                ioexception.printStackTrace();
+                ServerInternalException.reportInternalException(ioexception);
+            }
+            itr.remove();
+        }
+    }
+    // Paper End
+
+    public static synchronized void a() {
+        Iterator iterator = RegionFileCache.a.values().iterator();
+
+        while (iterator.hasNext()) {
+            RegionFile regionfile = (RegionFile) iterator.next();
+
+            try {
+                if (regionfile != null) {
+                    regionfile.c();
+                }
+            } catch (IOException ioexception) {
+                ioexception.printStackTrace();
+                ServerInternalException.reportInternalException(ioexception); // Paper
+            }
+        }
+
+        RegionFileCache.a.clear();
+    }
+
+    // CraftBukkit start - call sites hoisted for synchronization
+    public static synchronized NBTTagCompound d(File file, int i, int j) throws IOException {
+        RegionFile regionfile = a(file, i, j);
+
+        DataInputStream datainputstream = regionfile.a(i & 31, j & 31);
+
+        if (datainputstream == null) {
+            return null;
+        }
+
+        return NBTCompressedStreamTools.a(datainputstream);
+    }
+
+    public static synchronized void e(File file, int i, int j, NBTTagCompound nbttagcompound) throws IOException {
+        RegionFile regionfile = a(file, i, j);
+
+        DataOutputStream dataoutputstream = regionfile.b(i & 31, j & 31);
+        NBTCompressedStreamTools.a(nbttagcompound, (java.io.DataOutput) dataoutputstream);
+        dataoutputstream.close();
+    }
+    // CraftBukkit end
+
+    public static synchronized boolean chunkExists(File file, int i, int j) {
+        RegionFile regionfile = b(file, i, j);
+
+        return regionfile != null ? regionfile.c(i & 31, j & 31) : false;
+    }
+}