Rewrite chunk system (#8177)

Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.

1 files changed, 155 insertions, 0 deletions

diff --git a/patches/server/0308-Fire-event-on-GS4-query.patch b/patches/server/0308-Fire-event-on-GS4-query.patch
new file mode 100644
index 0000000000..445725e8b8
--- /dev/null
+++ b/patches/server/0308-Fire-event-on-GS4-query.patch
@@ -0,0 +1,155 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Mark Vainomaa <[email protected]>
+Date: Sun, 17 Mar 2019 21:46:56 +0200
+Subject: [PATCH] Fire event on GS4 query
+
+
+diff --git a/src/main/java/net/minecraft/server/rcon/NetworkDataOutputStream.java b/src/main/java/net/minecraft/server/rcon/NetworkDataOutputStream.java
+index 51cb2644aa516a59e19fecb308d519dbc7e5fb11..e548aa0ca4e1e94ab628614b44fc11568ca3beff 100644
+--- a/src/main/java/net/minecraft/server/rcon/NetworkDataOutputStream.java
++++ b/src/main/java/net/minecraft/server/rcon/NetworkDataOutputStream.java
+@@ -22,6 +22,16 @@ public class NetworkDataOutputStream {
+         this.dataOutputStream.write(0);
+     }
+ 
++    // Paper start - unchecked exception variant to use in Stream API
++    public void writeStringUnchecked(String string) {
++        try {
++            writeString(string);
++        } catch (IOException e) {
++            com.destroystokyo.paper.util.SneakyThrow.sneaky(e);
++        }
++    }
++    // Paper end
++
+     public void write(int value) throws IOException {
+         this.dataOutputStream.write(value);
+     }
+diff --git a/src/main/java/net/minecraft/server/rcon/thread/QueryThreadGs4.java b/src/main/java/net/minecraft/server/rcon/thread/QueryThreadGs4.java
+index 88917d7a179739fc13c59831b15e7ddc711bed1b..1ef089dbf83de35d875c00efdf468c397be56978 100644
+--- a/src/main/java/net/minecraft/server/rcon/thread/QueryThreadGs4.java
++++ b/src/main/java/net/minecraft/server/rcon/thread/QueryThreadGs4.java
+@@ -106,13 +106,32 @@ public class QueryThreadGs4 extends GenericThread {
+                         NetworkDataOutputStream networkDataOutputStream = new NetworkDataOutputStream(1460);
+                         networkDataOutputStream.write(0);
+                         networkDataOutputStream.writeBytes(this.getIdentBytes(packet.getSocketAddress()));
+-                        networkDataOutputStream.writeString(this.serverName);
++
++                        com.destroystokyo.paper.event.server.GS4QueryEvent.QueryType queryType =
++                            com.destroystokyo.paper.event.server.GS4QueryEvent.QueryType.BASIC;
++                        com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse queryResponse = com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse.builder()
++                            .motd(this.serverName)
++                            .map(this.worldName)
++                            .currentPlayers(this.serverInterface.getPlayerCount())
++                            .maxPlayers(this.maxPlayers)
++                            .port(this.serverPort)
++                            .hostname(this.hostIp)
++                            .gameVersion(this.serverInterface.getServerVersion())
++                            .serverVersion(org.bukkit.Bukkit.getServer().getName() + " on " + org.bukkit.Bukkit.getServer().getBukkitVersion())
++                            .build();
++                        com.destroystokyo.paper.event.server.GS4QueryEvent queryEvent =
++                            new com.destroystokyo.paper.event.server.GS4QueryEvent(queryType, packet.getAddress(), queryResponse);
++                        queryEvent.callEvent();
++                        queryResponse = queryEvent.getResponse();
++
++                        networkDataOutputStream.writeString(queryResponse.getMotd());
+                         networkDataOutputStream.writeString("SMP");
+-                        networkDataOutputStream.writeString(this.worldName);
+-                        networkDataOutputStream.writeString(Integer.toString(this.serverInterface.getPlayerCount()));
+-                        networkDataOutputStream.writeString(Integer.toString(this.maxPlayers));
+-                        networkDataOutputStream.writeShort((short)this.serverPort);
+-                        networkDataOutputStream.writeString(this.hostIp);
++                        networkDataOutputStream.writeString(queryResponse.getMap());
++                        networkDataOutputStream.writeString(Integer.toString(queryResponse.getCurrentPlayers()));
++                        networkDataOutputStream.writeString(Integer.toString(queryResponse.getMaxPlayers()));
++                        networkDataOutputStream.writeShort((short) queryResponse.getPort());
++                        networkDataOutputStream.writeString(queryResponse.getHostname());
++                        // Paper end
+                         this.sendTo(networkDataOutputStream.toByteArray(), packet);
+                         LOGGER.debug("Status [{}]", (Object)socketAddress);
+                     }
+@@ -147,31 +166,75 @@ public class QueryThreadGs4 extends GenericThread {
+             this.rulesResponse.writeString("splitnum");
+             this.rulesResponse.write(128);
+             this.rulesResponse.write(0);
++            // Paper start
++            // Pack plugins
++            java.util.List<com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse.PluginInformation> plugins = java.util.Collections.emptyList();
++            org.bukkit.plugin.Plugin[] bukkitPlugins;
++            if (((net.minecraft.server.dedicated.DedicatedServer) this.serverInterface).server.getQueryPlugins() && (bukkitPlugins = org.bukkit.Bukkit.getPluginManager().getPlugins()).length > 0) {
++                plugins = java.util.stream.Stream.of(bukkitPlugins)
++                    .map(plugin -> com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse.PluginInformation.of(plugin.getName(), plugin.getDescription().getVersion()))
++                    .collect(java.util.stream.Collectors.toList());
++            }
++
++            com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse queryResponse = com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse.builder()
++                .motd(this.serverName)
++                .map(this.worldName)
++                .currentPlayers(this.serverInterface.getPlayerCount())
++                .maxPlayers(this.maxPlayers)
++                .port(this.serverPort)
++                .hostname(this.hostIp)
++                .plugins(plugins)
++                .players(this.serverInterface.getPlayerNames())
++                .gameVersion(this.serverInterface.getServerVersion())
++                .serverVersion(org.bukkit.Bukkit.getServer().getName() + " on " + org.bukkit.Bukkit.getServer().getBukkitVersion())
++                .build();
++            com.destroystokyo.paper.event.server.GS4QueryEvent.QueryType queryType =
++                com.destroystokyo.paper.event.server.GS4QueryEvent.QueryType.FULL;
++            com.destroystokyo.paper.event.server.GS4QueryEvent queryEvent =
++                new com.destroystokyo.paper.event.server.GS4QueryEvent(queryType, packet.getAddress(), queryResponse);
++            queryEvent.callEvent();
++            queryResponse = queryEvent.getResponse();
+             this.rulesResponse.writeString("hostname");
+-            this.rulesResponse.writeString(this.serverName);
++            this.rulesResponse.writeString(queryResponse.getMotd());
+             this.rulesResponse.writeString("gametype");
+             this.rulesResponse.writeString("SMP");
+             this.rulesResponse.writeString("game_id");
+             this.rulesResponse.writeString("MINECRAFT");
+             this.rulesResponse.writeString("version");
+-            this.rulesResponse.writeString(this.serverInterface.getServerVersion());
++            this.rulesResponse.writeString(queryResponse.getGameVersion());
+             this.rulesResponse.writeString("plugins");
+-            this.rulesResponse.writeString(this.serverInterface.getPluginNames());
++            java.lang.StringBuilder pluginsString = new java.lang.StringBuilder();
++            pluginsString.append(queryResponse.getServerVersion());
++            if (!queryResponse.getPlugins().isEmpty()) {
++                pluginsString.append(": ");
++                java.util.Iterator<com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse.PluginInformation> iter = queryResponse.getPlugins().iterator();
++                while (iter.hasNext()) {
++                    com.destroystokyo.paper.event.server.GS4QueryEvent.QueryResponse.PluginInformation info = iter.next();
++                    pluginsString.append(info.getName());
++                    if (info.getVersion() != null) {
++                        pluginsString.append(' ').append(info.getVersion().replace(";", ","));
++                    }
++                    if (iter.hasNext()) {
++                        pluginsString.append(';').append(' ');
++                    }
++                }
++            }
++            this.rulesResponse.writeString(pluginsString.toString());
+             this.rulesResponse.writeString("map");
+-            this.rulesResponse.writeString(this.worldName);
++            this.rulesResponse.writeString(queryResponse.getMap());
+             this.rulesResponse.writeString("numplayers");
+-            this.rulesResponse.writeString("" + this.serverInterface.getPlayerCount());
++            this.rulesResponse.writeString(Integer.toString(queryResponse.getCurrentPlayers()));
+             this.rulesResponse.writeString("maxplayers");
+-            this.rulesResponse.writeString("" + this.maxPlayers);
++            this.rulesResponse.writeString(Integer.toString(queryResponse.getMaxPlayers()));
+             this.rulesResponse.writeString("hostport");
+-            this.rulesResponse.writeString("" + this.serverPort);
++            this.rulesResponse.writeString(Integer.toString(queryResponse.getPort()));
+             this.rulesResponse.writeString("hostip");
+-            this.rulesResponse.writeString(this.hostIp);
++            this.rulesResponse.writeString(queryResponse.getHostname());
+             this.rulesResponse.write(0);
+             this.rulesResponse.write(1);
+             this.rulesResponse.writeString("player_");
+             this.rulesResponse.write(0);
+-            String[] strings = this.serverInterface.getPlayerNames();
++            String[] strings = queryResponse.getPlayers().toArray(String[]::new);
+ 
+             for(String string : strings) {
+                 this.rulesResponse.writeString(string);