## Problem
On headless Linux deployments (systemd service, Docker without a TTY, `nohup`), the ModernUO process pegs a full CPU core even when idle. It does not reproduce on Windows because that runs with an interactive console.
## Root cause
`ConsoleInputHandler` runs a background thread (named "Console Input Handler") that loops on `Console.ReadLine()`. When stdin is **not** an interactive terminal, `Console.ReadLine()` returns `null` at end-of-stream **immediately** on every call, so the loop `continue`s in a tight spin — one core at 100%.
Reproduced in a container running the actual distribution: the "Console Input Handler" thread sat at ~90% CPU on a headless boot; with a blocking stdin it dropped to idle.
## Fix
1. **Detect headless once at startup:** `Core.Headless = Console.IsInputRedirected`.
2. **Extract a testable `ConsoleInputPump`** that owns the input stream: per line read, it *atomically* (under one lock) either delivers the line to a waiting prompt or dispatches a console command, and it **ends on EOF instead of spinning**. Cleanup runs unconditionally in a `finally`, so a pending prompt is always released (never hangs). Replaces the old `async void` loop and the fragile `_expectUserInput` / two-`AutoResetEvent` / `_input` handshake.
3. **`ConsoleInputHandler` becomes a thin headless-aware facade** over the pump. Headless: the reader thread never starts (`Console input disabled (headless: stdin is not a TTY).`), and `ReadLine()` throws a fatal `HeadlessConsoleInputException`.
4. **Data-gating and first-boot prompts** (deserialization "delete bad types? y/n", save-conflict, config/expansion setup) now route through `ConsoleInputHandler.ReadLine()`, so a headless server crashes fatal with a clear message instead of reading `null` (previously an NRE or a silent wrong branch).
Design decision (model b): headless servers are expected to be supplied with configuration/save data (including the owner account); interactive prompts when headless are fatal by design.
## Testing
- New `ConsoleInputPumpTests` (5 tests): EOF ends the loop without spinning; command dispatch; a pending prompt receives the next line; EOF while a prompt is pending completes it with `null` (no hang); a throwing command lookup does not hang a pending prompt. The tests synchronize on real pump state (no `Thread.Sleep`), so they are deterministic on slow CI.
- Full `Server.Tests`: no new failures introduced.
## End-to-end verification (Docker, real distribution)
| | Console Input Handler thread | Container CPU |
|---|---|---|
| Before fix (headless boot) | ~90% | ~199% (2 cores) |
| After fix (headless boot) | **not started** | **~11%** |
After the fix, a headless boot logs `Console input disabled (headless: stdin is not a TTY).`, loads the world normally, and idles instead of spinning.
### Summary
- `GenericEntityPersistence` is now a type of `GenericPersistence`. This allows developers to serialize both entities and non-entities in the same system. 🎉
- Each `SerializationThreadWorker` now allocates 1MB of heap for serialization _permanently_. If more memory is needed, that thread will double it's memory, not to exceed increments of 64MB.
- Several bugs with serialization introduced with the pure MMF implementation have been fixed.
- `BinaryFileReader` has been added back. 🎉
- Adds `world.useMultithreadedSaves` to allow disabling threaded saves.
> [!IMPORTANT]
> **Developer Note**
> The split file serialization has been deprecated and is no longer used. We have effectively gone back to the same file writing we had before the pure MMF implementation.
### Summary
Updates the serialization strategy to use `MemoryMappedFile` instead of thick buffers. This has the benefit of being on-par with the current implementation (based on hardware/OS), however won't incur the double-memory issue.
> [!Important]
> **Developer Note**
> The `BinaryFileWriter` and `BinaryFileReader` has been removed in favor of `MemoryMapFileWriter` and `UnmanagedDataReader`
### Summary
- [X] Fixed a bug where entity persistence was serialized out of order, causing world corruption.
- [X] Fixed LastSerialized not being utilized properly and dangling references still becoming an issue.
- [X] Added a new `GenericEntityPersistence<T>` type to encapsulate `ISerializable` serialization.
- [X] Removing the custom logic and moved Items, Mobiles, Guilds, and Accounts to GenericEntityPersistence.
- [X] Changed serialization to use the singleton pattern to reduce calling methods from stored variables.
## MAJOR CHANGE
Added a champion title system to facilitate the existing champion titles. This should make it easier to extend or create other related game content. Champion titles will be saved in a folder called _ChampionTitles_.
### Motivation
The motivation to refactor was two-folder, but mostly related to performance in two ways.
First, every player had a ChampionTitleInfo object with an array of ChamptionTitleInfo. We want to eliminate the need for this information unless a player actually uses it. This should save a considerable amount of memory.
Second, to facilitate the atrophy mechanic, the champion titles would run atrophy post-world save, adding to the time that the server is frozen. Eliminating this post-world save side effect unlocks our ability to further optimize the world save process since there are no direct side effects.
### Bugs fixed
- [X] Fixed titles getting cut off on the paperdoll
- [X] Fixed champion title not displaying overhead (OPL)
### Screenshots
<img width="216" alt="image" src="https://github.com/modernuo/ModernUO/assets/3953314/8916f895-8d68-4fb0-892e-108a0c43be90">
### Changes
* Implements an AfterSerialize method that is executed synchronously.
* Removes `BeforeSerialize` support since it was dangerous in its current implementation.
* Moves PlayerMobile kill/virtual decay to AfterSerialize.
* Adds kill decay to after Deserialize.
## Changes
* Improves type hashing by introducing xxHash3 (64bit)
* Removes individual `tdb` files in favor of a single `SerializedTypes.db` file. This file is only used to identify a type that is being deserialized, which doesn't exist.
* Adds duplicate type alias detection
* Adds `AssemblyHandler.FindTypeByHash`
View changed files whitespaces: https://github.com/modernuo/ModernUO/pull/1172/files?diff=split&w=1
## SerializedTypes.db
The serialized types file is used to get back the original name of a type in case it no longer exists in code. This can easily be necessary if a class is renamed in code and no `TypeAlias` is provided.
### Format
byte[4] - version
byte[4] - count
--array--
byte[8] - xxHash
byte[1] - flag, 0 - null, 1 - not null
byte[n] - Full class name in UTF8
### Example
<img width="472" alt="SerializedTypes_Example" src="https://user-images.githubusercontent.com/3953314/195255429-31d24293-6bd1-419e-811b-07874dd0f78d.png">
## Benchmarks
Serialized 500 Type fields. The 8192bytes comes from the _ConcurrentQueue_ that would later be used for SerializedTypes.
Note that the queue is never cleared, so it's size grew considerably.
```cs
| Method | Mean | Error | StdDev | Allocated |
|--------------------- |---------:|---------:|---------:|----------:|
| BenchmarkXXHash | 18.44 us | 0.278 us | 0.260 us | 8192 B |
| BenchmarkTypeStrings | 25.09 us | 0.292 us | 0.259 us | - |
```
TODO:
* Add support in the Serialization Generator for `ReadType()` and `Write(Type)`
* Remove `SetTypeRef` from Serialization Generator
**Only one functional change**
* Fixes a bug in LogFactory where `Warning` is being logged as `Information`
Non-functional changes:
* Updates/Fixes copyright headers
* Removes namespace scopes for core files.
View with [whitespace off](https://github.com/modernuo/ModernUO/pull/1187/files?w=1).
* Makes EnsureDirectory properly work for relative and absolute paths
* Adds a `PathUtility.GetFullPath` which returns full paths for relative paths to `Core.BaseDirectory`. If the path is absolute, it will return as-is.
* Moves EnsureDirectory to `PathUtility`. So `ScriptsHandler.EnsureDirectory` and `AssemblyHandler.EnsureDirectory` are now `PathUtility.EnsureDirectory`
* Fixes crash guard so that it copies accounts properly.
* Changes world save and auto archive to use a random folder name inside of the temp folder.
### Features
* Fully abstracts serialization by using compile-time attributes.
* Supports serializing the following:
- Primitives (integers, strings, etc)
- IP Addresses
- BigDecimal
- DateTime, Delta DateTimes
- TimeSpan
- Server.Race
- Server.Map
- Point2D, Point3D, Rect2D, Rect3D
- Existing/New `ISerializable` references
- Lists/Sets of serializable types
- Type with a `Serialize` method and constructor that takes an `IGenericReader`
* Supports forward-only migration
* Supports existing RunUO deserialization for older versions by changing to the following signature:
- `public void OldDeserialize(IGenericReader reader, int version)`
- Must remove deserializing the version since this is already done
* Supports serializing from private fields or custom made properties.
* Types do not require inheriting Item/Mobile. Code gen will fully create `ISerializable` information.
- This is not recommended yet, since it requires wiring to `Persistence` which will cause lots of unresolved symbol errors until code gen is built.
### Example
```cs
using System.Collections.Generic;
namespace Server.Items
{
[Serializable(1)]
public partial class TestItem1 : Item
{
[SerializableField(1)]
[SerializableFieldAttr("[CommandProperty(AccessLevel.Administrator)]")]
private List<Item> _someProperty;
private void Deserialize(IGenericReader reader, int version)
{
}
}
}
```
Generates this:
```cs
namespace Server.Items
{
public partial class TestItem1
{
#pragma warning disable 0414
private const int _version = 1;
#pragma warning restore 0414
[CommandProperty(AccessLevel.Administrator)]
public System.Collections.Generic.List<Server.Item> SomeProperty
{
get => _someProperty;
set
{
if (value != _someProperty)
{
((ISerializable)this).MarkDirty();
_someProperty = value;
}
}
}
public TestItem1(Serial serial) : base(serial)
{
}
public override void Serialize(IGenericWriter writer)
{
var savePosition = ((Server.ISerializable)this).SavePosition;
if (savePosition > -1)
{
writer.Seek(savePosition, System.IO.SeekOrigin.Begin);
return;
}
writer.WriteEncodedInt(_version);
writer.Write(_someProperty);
}
public override void Deserialize(IGenericReader reader)
{
var version = reader.ReadEncodedInt();
if (version < 1)
{
OldDeserialize(reader, version);
((Server.ISerializable)this).MarkDirty();
return;
}
SomeProperty = reader.ReadEntityList<Server.Item>();
}
}
}
```
And this:
```json
{
"version": 1,
"type": "TestItem1",
"properties": [
{
"name": "SomeProperty",
"type": "System.Collections.Generic.List\u003CServer.Item\u003E",
"rule": "ListMigrationRule",
"ruleArguments": [
"Server.Item",
"SerializableInterfaceMigrationRule"
]
}
]
}
```
- [X] Adds `AdhocPersistence` which replaces RunUO `Persistence`
- [X] Fixes a few minor bugs with EntityPersistence deserialization
- [X] Reverts/updates some serialization changes
- [X] Fixes generic persistence, making the API for writing from a static class much easier.
Example:
```cs
namespace Server
{
public static class ExampleSystem
{
public static void Configure()
{
GenericPersistence.Register("ExampleSystem", Serialize, Deserialize);
}
public static void Serialize(IGenericWriter writer)
{
// Do serialization here
writer.WriteEncodedInt(0); // version
}
public static void Deserialize(IGenericReader reader)
{
// Do deserialization here
var version = reader.ReadEncodedInt();
}
}
}
```
