Leaf/patches/server/0129-Use-faster-and-thread-safe-ban-list-date-format-pars.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Dreeam <61569423+Dreeam-qwq@users.noreply.github.com>
Date: Mon, 11 Nov 2024 02:46:39 -0500
Subject: [PATCH] Use faster and thread-safe ban list date format parsing

Dreeam TODO: check is there need to use more accurate benchmark using jmh?

Use DateTimeFormatter since the original java SimpleDateFormat is not thread-safe
If calls DateTimeFormatter asynchronously, one data format may pollute another

This can fix the server crash on loading according to the user report.
The server crashed during initing the IP ban list, probably caused by calls in off-main.

Some performance test **only for reference**
Single thread, 10,000,000 times loop, java 21 (graalvm / zulu)

SimpleDateFormat:                       ~29,446ms
DateTimeFormatter:                      ~13,128ms
apache commons-lang's FastDateFormat:   ~23,514ms

In the end, DateTimeFormatter is also fastest in three implementations in any ways,
Wether there is a high frequnently calls or not. And also thread-safe. So there is
a better solution, why not using it?

diff --git a/src/main/java/net/minecraft/server/players/BanListEntry.java b/src/main/java/net/minecraft/server/players/BanListEntry.java
index 8b1da1fb5ca27432a39aff6dbc452b793268dab5..46188a8b8598c36ccb0f5e037a80eb1741c68491 100644
--- a/src/main/java/net/minecraft/server/players/BanListEntry.java
+++ b/src/main/java/net/minecraft/server/players/BanListEntry.java
@@ -10,7 +10,9 @@ import net.minecraft.network.chat.Component;
 
 public abstract class BanListEntry<T> extends StoredUserEntry<T> {
 
-    public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss Z", Locale.ROOT);
+    //public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss Z", Locale.ROOT); // Leaf - I assume no one will use this, if yes, why?
+    private static final java.time.ZoneId ZONE_ID = java.time.ZoneId.systemDefault();
+    public static final java.time.format.DateTimeFormatter DATE_TIME_FORMATTER = java.time.format.DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss Z"); // Leaf - Use faster and thread-safe ban list date format parsing
     public static final String EXPIRES_NEVER = "forever";
     protected final Date created;
     protected final String source;
@@ -32,8 +34,10 @@ public abstract class BanListEntry<T> extends StoredUserEntry<T> {
         Date date;
 
         try {
-            date = json.has("created") ? BanListEntry.DATE_FORMAT.parse(json.get("created").getAsString()) : new Date();
-        } catch (ParseException parseexception) {
+            // Leaf start - Use faster and thread-safe ban list date format parsing
+            date = json.has("created") ? parseToDate(json.get("created").getAsString()) : new Date();
+        } catch (java.time.format.DateTimeParseException e) {
+            // Leaf end - Use faster and thread-safe ban list date format parsing
             date = new Date();
         }
 
@@ -43,8 +47,10 @@ public abstract class BanListEntry<T> extends StoredUserEntry<T> {
         Date date1;
 
         try {
-            date1 = json.has("expires") ? BanListEntry.DATE_FORMAT.parse(json.get("expires").getAsString()) : null;
-        } catch (ParseException parseexception1) {
+            // Leaf start - Use faster and thread-safe ban list date format parsing
+            date1 = json.has("expires") ? parseToDate(json.get("expires").getAsString()) : null;
+        } catch (java.time.format.DateTimeParseException e) {
+            // Leaf end - Use faster and thread-safe ban list date format parsing
             date1 = null;
         }
 
@@ -78,9 +84,9 @@ public abstract class BanListEntry<T> extends StoredUserEntry<T> {
 
     @Override
     protected void serialize(JsonObject json) {
-        json.addProperty("created", BanListEntry.DATE_FORMAT.format(this.created));
+        json.addProperty("created", formateToString(this.created)); // Leaf - Use faster and thread-safe ban list date format parsing
         json.addProperty("source", this.source);
-        json.addProperty("expires", this.expires == null ? "forever" : BanListEntry.DATE_FORMAT.format(this.expires));
+        json.addProperty("expires", this.expires == null ? "forever" : formateToString(this.expires)); // Leaf - Use faster and thread-safe ban list date format parsing
         json.addProperty("reason", this.reason);
     }
 
@@ -89,9 +95,11 @@ public abstract class BanListEntry<T> extends StoredUserEntry<T> {
         Date expires = null;
 
         try {
-            expires = jsonobject.has("expires") ? BanListEntry.DATE_FORMAT.parse(jsonobject.get("expires").getAsString()) : null;
-        } catch (ParseException ex) {
+            // Leaf start - Use faster and thread-safe ban list date format parsing
+            expires = jsonobject.has("expires") ? parseToDate(jsonobject.get("expires").getAsString()) : null;
+        } catch (java.time.format.DateTimeParseException ignored) {
             // Guess we don't have a date
+            // Leaf end - Use faster and thread-safe ban list date format parsing
         }
 
         if (expires == null || expires.after(new Date())) {
@@ -101,4 +109,15 @@ public abstract class BanListEntry<T> extends StoredUserEntry<T> {
         }
     }
     // CraftBukkit end
+
+    // Leaf start - Use faster and thread-safe ban list date format parsing
+    public static Date parseToDate(String string) {
+        java.time.ZonedDateTime parsedDateTime = java.time.ZonedDateTime.parse(string, DATE_TIME_FORMATTER);
+        return Date.from(parsedDateTime.toInstant());
+    }
+
+    public static String formateToString(Date date) {
+        return DATE_TIME_FORMATTER.format(date.toInstant().atZone(ZONE_ID));
+    }
+    // Leaf end - Use faster and thread-safe ban list date format parsing
 }
diff --git a/src/main/java/net/minecraft/server/players/OldUsersConverter.java b/src/main/java/net/minecraft/server/players/OldUsersConverter.java
index 653856d0b8dcf2baf4cc77a276f17c8cc1fa717e..6416bc12f3d7733a4bd89d208a320f1b68983788 100644
--- a/src/main/java/net/minecraft/server/players/OldUsersConverter.java
+++ b/src/main/java/net/minecraft/server/players/OldUsersConverter.java
@@ -516,8 +516,10 @@ public class OldUsersConverter {
         Date date1;
 
         try {
-            date1 = BanListEntry.DATE_FORMAT.parse(dateString);
-        } catch (ParseException parseexception) {
+            // Leaf start - Use faster and thread-safe ban list date format parsing
+            date1 = BanListEntry.parseToDate(dateString);
+        } catch (java.time.format.DateTimeParseException e) {
+            // Leaf end - Use faster and thread-safe ban list date format parsing
             date1 = fallback;
         }