From a1b78729ad268fc1bb764e0432ff606abb0f7f86 Mon Sep 17 00:00:00 2001
From: Antony Riley <antony@cyberiantiger.org>
Date: Tue, 29 Mar 2016 08:22:55 +0300
Subject: [PATCH] Sanitise RegionFileCache and make configurable.

RegionFileCache prior to this patch would close every single open region
file upon reaching a size of 256.
This patch modifies that behaviour so it closes the the least recently
used RegionFile.
The implementation uses a LinkedHashMap as an LRU cache (modified from HashMap).
The maximum size of the RegionFileCache is also made configurable.

diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index e4ba7146d1..06c53af2c5 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -228,4 +228,9 @@ public class PaperConfig {
     private static void loadPermsBeforePlugins() {
         loadPermsBeforePlugins = getBoolean("settings.load-permissions-yml-before-plugins", true);
     }
+
+    public static int regionFileCacheSize = 256;
+    private static void regionFileCacheSize() {
+        regionFileCacheSize = getInt("settings.region-file-cache-size", 256);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/RegionFileCache.java b/src/main/java/net/minecraft/server/RegionFileCache.java
index 5dbd1d517a..964996976a 100644
--- a/src/main/java/net/minecraft/server/RegionFileCache.java
+++ b/src/main/java/net/minecraft/server/RegionFileCache.java
@@ -9,10 +9,12 @@ import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
 import javax.annotation.Nullable;
+import com.destroystokyo.paper.PaperConfig; // Paper
+import java.util.LinkedHashMap; // Paper
 
 public class RegionFileCache {
 
-    public static final Map<File, RegionFile> cache = Maps.newHashMap();
+    public static final Map<File, RegionFile> cache = new LinkedHashMap(PaperConfig.regionFileCacheSize, 0.75f, true); // Paper - HashMap -> LinkedHashMap
 
     public static synchronized RegionFile a(File file, int i, int j) {
         File file1 = new File(file, "region");
@@ -27,7 +29,7 @@ public class RegionFileCache {
             }
 
             if (RegionFileCache.cache.size() >= 256) {
-                a();
+                trimCache();
             }
 
             RegionFile regionfile1 = new RegionFile(file2);
@@ -60,6 +62,22 @@ public class RegionFileCache {
     }
     // CraftBukkit end
 
+    // Paper Start
+    private static synchronized void trimCache() {
+        Iterator<Map.Entry<File, RegionFile>> itr = RegionFileCache.cache.entrySet().iterator();
+        int count = RegionFileCache.cache.size() - PaperConfig.regionFileCacheSize;
+        while (count-- >= 0 && itr.hasNext()) {
+            try {
+                itr.next().getValue().close();
+            } catch (IOException ioexception) {
+                ioexception.printStackTrace();
+                ServerInternalException.reportInternalException(ioexception);
+            }
+            itr.remove();
+        }
+    }
+    // Paper End
+
     public static synchronized void a() {
         Iterator iterator = RegionFileCache.cache.values().iterator();
 
-- 
2.21.0