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Use ConcurrentHashMap in JsonList & Optimize (#471) (#1309)

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* [CI-SKIP] add .editorconfig for base code style settings

* * Created patch 0349 (fixes #471)

* * Made requested modifications

* * Made requested modifications (x2)

* * Made recommended changes (x3)

* * Moved ConcurrentMap return values to Map as no functions specific to ConcurrentMap were used (backing map is still ConcurrentMap)
* Removed ConcurrentMap import
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egg82 2018-08-11 06:46:46 -06:00
parent d1ceb803d3
commit d1f6595317
1 changed files with 112 additions and 0 deletions
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Spigot-Server-Patches/Use-ConcurrentHashMap-in-JsonList.patch Normal file
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: egg82 <eggys82@gmail.com>
Date: Tue, 7 Aug 2018 01:24:23 -0600
Subject: [PATCH] Use ConcurrentHashMap in JsonList
This is specifically aimed at fixing #471
Using a ConcurrentHashMap because thread safety
The performance benefit of Map over ConcurrentMap is negligabe at best in this scenaio, as most operations will be get and not add or remove
Even without considering the use-case the benefits are still negligable
Original ideas for the system included an expiration policy and/or handler
The simpler solution was to use a computeIfPresent in the get method
This will simultaneously have an O(1) lookup time and automatically expire any values
Since the get method (nor other similar methods) don't seem to have a critical need to flush the map to disk at any of these points further processing is simply wasteful
Meaning the original function expired values unrelated to the current value without actually having any explicit need to
The h method was heavily modified to be much more efficient in its processing
Also instead of being called on every get, it's now called just before a save
This will eliminate stale values being flushed to disk
Modified isEmpty to use the isEmpty() method instead of the slightly confusing size() < 1
The point of this is readability, but does have a side-benefit of a small microptimization
Finally, added a couple obfhelpers for the modified code
diff --git a/src/main/java/net/minecraft/server/JsonList.java b/src/main/java/net/minecraft/server/JsonList.java
index 0859c7eb2..93111cc24 100644
--- a/src/main/java/net/minecraft/server/JsonList.java
+++ b/src/main/java/net/minecraft/server/JsonList.java
@@ -0,0 +0,0 @@ import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
+
import org.apache.commons.io.IOUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
@@ -0,0 +0,0 @@ public class JsonList<K, V extends JsonListEntry<K>> {
protected static final Logger a = LogManager.getLogger();
protected final Gson b;
private final File c;
- private final Map<String, V> d = Maps.newHashMap();
+ // Paper - replace HashMap is ConcurrentHashMap
+ private final Map<String, V> d = Maps.newConcurrentMap(); private final Map<String, V> getBackingMap() { return this.d; } // Paper - OBFHELPER
private boolean e = true;
private static final ParameterizedType f = new ParameterizedType() {
public Type[] getActualTypeArguments() {
@@ -0,0 +0,0 @@ public class JsonList<K, V extends JsonListEntry<K>> {
}
public V get(K k0) {
- this.h();
- return (V) this.d.get(this.a(k0)); // CraftBukkit - fix decompile error
+ // Paper start
+ // this.h();
+ // return (V) this.d.get(this.a(k0)); // CraftBukkit - fix decompile error
+ return (V) this.getBackingMap().computeIfPresent(this.getMappingKey(k0), (k, v) -> {
+ return v.hasExpired() ? null : v;
+ });
+ // Paper end
}
public void remove(K k0) {
@@ -0,0 +0,0 @@ public class JsonList<K, V extends JsonListEntry<K>> {
// CraftBukkit end
public boolean isEmpty() {
- return this.d.size() < 1;
+ // return this.d.size() < 1; // Paper
+ return this.getBackingMap().isEmpty(); // Paper - readability is the goal. As an aside, isEmpty() uses only sumCount() and a comparison. size() uses sumCount(), casts, and boolean logic
}
+ protected final String getMappingKey(K k0) { return a(k0); } // Paper - OBFHELPER
protected String a(K k0) {
return k0.toString();
}
@@ -0,0 +0,0 @@ public class JsonList<K, V extends JsonListEntry<K>> {
return this.d.containsKey(this.a(k0));
}
+ private void removeStaleEntries() { h(); } // Paper - OBFHELPER
private void h() {
- ArrayList arraylist = Lists.newArrayList();
+ // Paper start
+ /*ArrayList arraylist = Lists.newArrayList();
Iterator iterator = this.d.values().iterator();
while (iterator.hasNext()) {
@@ -0,0 +0,0 @@ public class JsonList<K, V extends JsonListEntry<K>> {
Object object = iterator.next();
this.d.remove(object);
- }
-
+ }*/
+
+ this.getBackingMap().values().removeIf((v) -> v.hasExpired());
+ // Paper end
}
protected JsonListEntry<K> a(JsonObject jsonobject) {
@@ -0,0 +0,0 @@ public class JsonList<K, V extends JsonListEntry<K>> {
}
public void save() throws IOException {
+ this.removeStaleEntries(); // Paper - remove expired values before saving
+
Collection collection = this.d.values();
String s = this.b.toJson(collection);
BufferedWriter bufferedwriter = null;
--