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using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Linq;
using System.Threading.Tasks;
using System.Threading;
using IPA.Utilities.Async;
using System.IO;
using Logger = IPA.Logging.Logger;
#if NET4
using Task = System.Threading.Tasks.Task;
using TaskEx = System.Threading.Tasks.Task;
#endif
namespace IPA.Config
{
internal static class ConfigRuntime
{
private class DirInfoEqComparer : IEqualityComparer<DirectoryInfo>
{
public bool Equals(DirectoryInfo x, DirectoryInfo y)
=> x?.FullName == y?.FullName;
public int GetHashCode(DirectoryInfo obj)
=> obj?.FullName.GetHashCode() ?? 0;
}
private static readonly ConcurrentBag<Config> configs = new();
private static readonly AutoResetEvent configsChangedWatcher = new(false);
private static readonly ConcurrentDictionary<DirectoryInfo, FileSystemWatcher> watchers = new(new DirInfoEqComparer());
private static readonly ConcurrentDictionary<FileSystemWatcher, ConcurrentBag<Config>> watcherTrackConfigs = new();
private static BlockingCollection<IConfigStore> requiresSave = new();
private static SingleThreadTaskScheduler loadScheduler;
private static TaskFactory loadFactory;
private static Thread saveThread;
private static Thread legacySaveThread;
private static void TryStartRuntime()
{
if (loadScheduler == null || !loadScheduler.IsRunning)
{
loadFactory = null;
loadScheduler = new SingleThreadTaskScheduler();
loadScheduler.Start();
}
if (loadFactory == null)
loadFactory = new TaskFactory(loadScheduler);
if (saveThread == null || !saveThread.IsAlive)
{
saveThread = new Thread(SaveThread);
saveThread.Start();
}
if (legacySaveThread == null || !legacySaveThread.IsAlive)
{
legacySaveThread = new Thread(LegacySaveThread);
legacySaveThread.Start();
}
AppDomain.CurrentDomain.ProcessExit -= ShutdownRuntime;
AppDomain.CurrentDomain.ProcessExit += ShutdownRuntime;
}
internal static void AddRequiresSave(IConfigStore configStore)
{
requiresSave?.Add(configStore);
}
private static void ShutdownRuntime(object sender, EventArgs e)
=> ShutdownRuntime();
internal static void ShutdownRuntime()
{
try
{
watcherTrackConfigs.Clear();
var watchList = watchers.ToArray();
watchers.Clear();
foreach (var pair in watchList)
pair.Value.EnableRaisingEvents = false;
loadScheduler.Join(); // we can wait for the loads to finish
saveThread.Abort(); // eww, but i don't like any of the other potential solutions
legacySaveThread.Abort();
SaveAll();
requiresSave.Dispose();
requiresSave = null;
}
catch
{
}
}
public static void RegisterConfig(Config cfg)
{
lock (configs)
{ // we only lock this segment, so that this only waits on other calls to this
if (configs.ToArray().Contains(cfg))
throw new InvalidOperationException("Config already registered to runtime!");
configs.Add(cfg);
}
configsChangedWatcher.Set();
TryStartRuntime();
AddConfigToWatchers(cfg);
}
public static void ConfigChanged()
{
configsChangedWatcher.Set();
}
private static void AddConfigToWatchers(Config config)
{
var dir = config.File.Directory;
if (!watchers.TryGetValue(dir, out var watcher))
{ // create the watcher
watcher = watchers.GetOrAdd(dir, dir => new FileSystemWatcher(dir.FullName));
watcher.NotifyFilter =
NotifyFilters.FileName
| NotifyFilters.LastWrite
| NotifyFilters.Size
| NotifyFilters.LastAccess
| NotifyFilters.Attributes
| NotifyFilters.CreationTime;
watcher.Changed += FileChangedEvent;
watcher.Created += FileChangedEvent;
watcher.Renamed += FileChangedEvent;
watcher.Deleted += FileChangedEvent;
}
TryStartRuntime();
watcher.EnableRaisingEvents = false; // disable while we do shit
var bag = watcherTrackConfigs.GetOrAdd(watcher, w => new ConcurrentBag<Config>());
// we don't need to check containment because this function will only be called once per config ever
bag.Add(config);
watcher.EnableRaisingEvents = true;
}
internal static FileSystemWatcher[] GetWatchers()
{
return watcherTrackConfigs.Keys.ToArray();
}
private static void EnsureWritesSane(Config config)
{
// compare exchange loop to be sane
var writes = config.Writes;
while (writes < 0)
writes = Interlocked.CompareExchange(ref config.Writes, 0, writes);
}
private static void FileChangedEvent(object sender, FileSystemEventArgs e)
{
var watcher = sender as FileSystemWatcher;
if (!watcherTrackConfigs.TryGetValue(watcher, out var bag)) return;
var config = bag.FirstOrDefault(c => c.File.FullName == e.FullPath);
if (config != null && Interlocked.Decrement(ref config.Writes) + 1 <= 0)
{
EnsureWritesSane(config);
TriggerFileLoad(config);
}
}
public static Task TriggerFileLoad(Config config)
=> loadFactory.StartNew(() => LoadTask(config));
public static Task TriggerLoadAll()
=> TaskEx.WhenAll(configs.Select(TriggerFileLoad));
/// <summary>
/// this is synchronous, unlike <see cref="TriggerFileLoad(Config)"/>
/// </summary>
/// <param name="config"></param>
public static void Save(Config config)
{
var store = config.Store;
try
{
using var readLock = Synchronization.LockRead(store.WriteSyncObject);
EnsureWritesSane(config);
Interlocked.Increment(ref config.Writes);
store.WriteTo(config.configProvider);
}
catch (ThreadAbortException)
{
throw;
}
catch (Exception e)
{
Logger.Config.Error($"{nameof(IConfigStore)} for {config.File} errored while writing to disk");
Logger.Config.Error(e);
}
}
/// <summary>
/// this is synchronous, unlike <see cref="TriggerLoadAll"/>
/// </summary>
public static void SaveAll()
{
foreach (var config in configs)
Save(config);
}
private static void LoadTask(Config config)
{ // these tasks will always be running in the same thread as each other
try
{
var store = config.Store;
using var writeLock = Synchronization.LockWrite(store.WriteSyncObject);
store.ReadFrom(config.configProvider);
}
catch (Exception e)
{
Logger.Config.Error($"{nameof(IConfigStore)} for {config.File} errored while reading from the {nameof(IConfigProvider)}");
Logger.Config.Error(e);
}
}
private static void SaveThread()
{
if (requiresSave == null)
{
return;
}
try
{
foreach (var item in requiresSave.GetConsumingEnumerable())
{
try
{
Save(configs.First((c) => c.Store != null && ReferenceEquals(c.Store.WriteSyncObject, item.WriteSyncObject)));
}
catch (ThreadAbortException)
{
break;
}
catch (Exception e)
{
Logger.Config.Error($"Error waiting for in-memory updates");
Logger.Config.Error(e);
Thread.Sleep(TimeSpan.FromSeconds(1));
}
}
}
catch (ThreadAbortException)
{
// we got aborted :(
}
}
private static void LegacySaveThread()
{
try
{
while (true)
{
var configArr = configs.Where(c => c.Store?.SyncObject != null).ToArray();
int index = -1;
try
{
var waitHandles = configArr.Select(c => c.Store.SyncObject)
.Prepend(configsChangedWatcher)
.ToArray();
index = WaitHandle.WaitAny(waitHandles);
}
catch (ThreadAbortException)
{
break;
}
catch (Exception e)
{
Logger.Config.Error($"Error waiting for in-memory updates");
Logger.Config.Error(e);
Thread.Sleep(TimeSpan.FromSeconds(1));
}
if (index <= 0)
{ // we got a signal that the configs collection changed, loop around, or errored
continue;
}
// otherwise, we have a thing that changed in a store
Save(configArr[index - 1]);
}
}
catch (ThreadAbortException)
{
// we got aborted :(
}
}
}
}