sharp-chat/SharpChat.Common/Configuration/StreamConfig.cs

112 lines
3.8 KiB
C#

using System;
using System.IO;
using System.Text;
using System.Threading;
namespace SharpChat.Configuration {
public class StreamConfig : IConfig {
private Stream Stream { get; }
private StreamReader StreamReader { get; }
private Mutex Lock { get; }
private const int LOCK_TIMEOUT = 10000;
private static readonly TimeSpan CACHE_LIFETIME = TimeSpan.FromMinutes(15);
public StreamConfig(string fileName)
: this(new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.Read, FileShare.ReadWrite)) {}
public StreamConfig(Stream stream) {
Stream = stream ?? throw new ArgumentNullException(nameof(stream));
if(!Stream.CanRead)
throw new ArgumentException(@"Provided stream must be readable.", nameof(stream));
if(!Stream.CanSeek)
throw new ArgumentException(@"Provided stream must be seekable.", nameof(stream));
StreamReader = new StreamReader(stream, new UTF8Encoding(false), false);
Lock = new Mutex();
}
public string ReadValue(string name, string fallback = null) {
if(!Lock.WaitOne(LOCK_TIMEOUT)) // don't catch this, if this happens something is Very Wrong
throw new ConfigLockException();
try {
Stream.Seek(0, SeekOrigin.Begin);
string line;
while((line = StreamReader.ReadLine()) != null) {
if(string.IsNullOrWhiteSpace(line))
continue;
line = line.TrimStart();
if(line.StartsWith(@";") || line.StartsWith(@"#"))
continue;
string[] parts = line.Split(' ', 2, StringSplitOptions.RemoveEmptyEntries);
if(parts.Length < 2 || !string.Equals(parts[0], name))
continue;
return parts[1];
}
} finally {
Lock.ReleaseMutex();
}
return fallback;
}
public T ReadValue<T>(string name, T fallback = default) {
object value = ReadValue(name);
if(value == null)
return fallback;
Type type = typeof(T);
if(value is string strVal) {
if(type == typeof(bool))
value = !string.Equals(strVal, @"0", StringComparison.InvariantCultureIgnoreCase)
&& !string.Equals(strVal, @"false", StringComparison.InvariantCultureIgnoreCase);
else if(type == typeof(string[]))
value = strVal.Split(' ');
}
try {
return (T)Convert.ChangeType(value, type);
} catch(InvalidCastException ex) {
throw new ConfigTypeException(ex);
}
}
public T SafeReadValue<T>(string name, T fallback) {
try {
return ReadValue(name, fallback);
} catch(ConfigTypeException) {
return fallback;
}
}
public IConfig ScopeTo(string prefix) {
return new ScopedConfig(this, prefix);
}
public CachedValue<T> ReadCached<T>(string name, T fallback = default, TimeSpan? lifetime = null) {
return new CachedValue<T>(this, name, lifetime ?? CACHE_LIFETIME, fallback);
}
private bool IsDisposed;
~StreamConfig()
=> DoDispose();
public void Dispose() {
DoDispose();
GC.SuppressFinalize(this);
}
private void DoDispose() {
if(IsDisposed)
return;
IsDisposed = true;
StreamReader.Dispose();
Stream.Dispose();
Lock.Dispose();
}
}
}