PaperMC/Spigot-API-Patches/0032-Reduce-thread-synchronization-in-MetadataStoreBase.patch

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From dd1173b521819609b5a9625b4da4a464ef403db7 Mon Sep 17 00:00:00 2001
From: crast <contact@jamescrasta.com>
Date: Sat, 1 Jun 2013 13:52:30 -0600
Subject: [PATCH] Reduce thread synchronization in MetadataStoreBase
Use ConcurrentHashMap to allow thread-safe access methods and very
limited synchronized portions to allow much higher concurrency in
MetadataStore as well as far less locking, especially on reads
diff --git a/src/main/java/org/bukkit/metadata/MetadataStoreBase.java b/src/main/java/org/bukkit/metadata/MetadataStoreBase.java
index 093c144..64c0f0a 100644
--- a/src/main/java/org/bukkit/metadata/MetadataStoreBase.java
+++ b/src/main/java/org/bukkit/metadata/MetadataStoreBase.java
@@ -4,9 +4,10 @@ import org.apache.commons.lang.Validate;
import org.bukkit.plugin.Plugin;
import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
public abstract class MetadataStoreBase<T> {
- private Map<String, Map<Plugin, MetadataValue>> metadataMap = new HashMap<String, Map<Plugin, MetadataValue>>();
+ private Map<String, Map<Plugin, MetadataValue>> metadataMap = new ConcurrentHashMap<String, Map<Plugin, MetadataValue>>();
/**
* Adds a metadata value to an object. Each metadata value is owned by a
@@ -30,7 +31,7 @@ public abstract class MetadataStoreBase<T> {
* @throws IllegalArgumentException If value is null, or the owning plugin
* is null
*/
- public synchronized void setMetadata(T subject, String metadataKey, MetadataValue newMetadataValue) {
+ public void setMetadata(T subject, String metadataKey, MetadataValue newMetadataValue) {
Validate.notNull(newMetadataValue, "Value cannot be null");
Plugin owningPlugin = newMetadataValue.getOwningPlugin();
Validate.notNull(owningPlugin, "Plugin cannot be null");
@@ -40,7 +41,9 @@ public abstract class MetadataStoreBase<T> {
entry = new WeakHashMap<Plugin, MetadataValue>(1);
metadataMap.put(key, entry);
}
- entry.put(owningPlugin, newMetadataValue);
+ synchronized (entry) {
+ entry.put(owningPlugin, newMetadataValue);
+ }
}
/**
@@ -53,10 +56,11 @@ public abstract class MetadataStoreBase<T> {
* requested value.
* @see MetadataStore#getMetadata(Object, String)
*/
- public synchronized List<MetadataValue> getMetadata(T subject, String metadataKey) {
+ public List<MetadataValue> getMetadata(T subject, String metadataKey) {
String key = disambiguate(subject, metadataKey);
- if (metadataMap.containsKey(key)) {
- Collection<MetadataValue> values = metadataMap.get(key).values();
+ Map<Plugin, MetadataValue> entry = metadataMap.get(key);
+ if (entry != null) {
+ Collection<MetadataValue> values = entry.values();
return Collections.unmodifiableList(new ArrayList<MetadataValue>(values));
} else {
return Collections.emptyList();
@@ -71,7 +75,7 @@ public abstract class MetadataStoreBase<T> {
* @param metadataKey the unique metadata key being queried.
* @return the existence of the metadataKey within subject.
*/
- public synchronized boolean hasMetadata(T subject, String metadataKey) {
+ public boolean hasMetadata(T subject, String metadataKey) {
String key = disambiguate(subject, metadataKey);
return metadataMap.containsKey(key);
}
@@ -87,17 +91,18 @@ public abstract class MetadataStoreBase<T> {
* org.bukkit.plugin.Plugin)
* @throws IllegalArgumentException If plugin is null
*/
- public synchronized void removeMetadata(T subject, String metadataKey, Plugin owningPlugin) {
+ public void removeMetadata(T subject, String metadataKey, Plugin owningPlugin) {
Validate.notNull(owningPlugin, "Plugin cannot be null");
String key = disambiguate(subject, metadataKey);
Map<Plugin, MetadataValue> entry = metadataMap.get(key);
if (entry == null) {
return;
}
-
- entry.remove(owningPlugin);
- if (entry.isEmpty()) {
- metadataMap.remove(key);
+ synchronized (entry) {
+ entry.remove(owningPlugin);
+ if (entry.isEmpty()) {
+ metadataMap.remove(key);
+ }
}
}
@@ -110,7 +115,7 @@ public abstract class MetadataStoreBase<T> {
* @see MetadataStore#invalidateAll(org.bukkit.plugin.Plugin)
* @throws IllegalArgumentException If plugin is null
*/
- public synchronized void invalidateAll(Plugin owningPlugin) {
+ public void invalidateAll(Plugin owningPlugin) {
Validate.notNull(owningPlugin, "Plugin cannot be null");
for (Map<Plugin, MetadataValue> values : metadataMap.values()) {
if (values.containsKey(owningPlugin)) {
--
2.8.0