From 44f23c2ed6040dcc9d5d79d9ce0031aa4547d8b1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=99=88=E5=9B=BD=E4=BC=9F?= <366193849@qq.com>
Date: Thu, 29 Jul 2021 15:14:27 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BC=98=E5=8C=96hosts=E6=A3=80=E6=B5=8B?=
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---
 FastGithub.Dns/HostsValidator.cs | 86 +++++++++++++++++++++-----------
 1 file changed, 57 insertions(+), 29 deletions(-)

diff --git a/FastGithub.Dns/HostsValidator.cs b/FastGithub.Dns/HostsValidator.cs
index 3ba84f4..31e954a 100644
--- a/FastGithub.Dns/HostsValidator.cs
+++ b/FastGithub.Dns/HostsValidator.cs
@@ -1,7 +1,7 @@
 using FastGithub.Configuration;
 using Microsoft.Extensions.Logging;
 using System;
-using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -48,45 +48,73 @@ namespace FastGithub.Dns
                 return;
             }
 
-            var lines = await File.ReadAllLinesAsync(hostsPath);
-            var records = lines.Where(item => item.TrimStart().StartsWith("#") == false);
-            var localAddresses = GetLocalMachineIPAddress().ToArray();
+            var localAddresses = IPGlobalProperties
+                .GetIPGlobalProperties()
+                .GetUnicastAddresses()
+                .Select(item => item.Address)
+                .ToArray();
 
-            foreach (var record in records)
+            var lines = await File.ReadAllLinesAsync(hostsPath);
+            foreach (var line in lines)
             {
+                if (HostsRecord.TryParse(line, out var record) == false)
+                {
+                    continue;
+                }
+                if (localAddresses.Contains(record.Address) == true)
+                {
+                    continue;
+                }
+                if (this.fastGithubConfig.IsMatch(record.Domain))
+                {
+                    this.logger.LogError($"由于你的hosts文件设置了[{record.Domain}->{record.Address}]，{nameof(FastGithub)}无法加速此域名");
+                }
+            }
+        }
+
+
+        /// <summary>
+        /// hosts文件记录
+        /// </summary>
+        private class HostsRecord
+        {
+            /// <summary>
+            /// 获取域名
+            /// </summary>
+            public string Domain { get; }
+
+            /// <summary>
+            /// 获取地址
+            /// </summary>
+            public IPAddress Address { get; }
+
+            private HostsRecord(string domain, IPAddress address)
+            {
+                this.Domain = domain;
+                this.Address = address;
+            }
+
+            public static bool TryParse(string record, [MaybeNullWhen(false)] out HostsRecord value)
+            {
+                value = null;
+                if (record.TrimStart().StartsWith("#"))
+                {
+                    return false;
+                }
+
                 var items = record.Split(' ', StringSplitOptions.RemoveEmptyEntries);
                 if (items.Length < 2)
                 {
-                    continue;
+                    return false;
                 }
 
                 if (IPAddress.TryParse(items[0], out var address) == false)
                 {
-                    continue;
+                    return false;
                 }
 
-                if (localAddresses.Contains(address))
-                {
-                    continue;
-                }
-
-                var domain = items[1];
-                if (this.fastGithubConfig.IsMatch(domain))
-                {
-                    this.logger.LogError($"由于你的hosts文件设置了[{domain}->{address}]，{nameof(FastGithub)}无法加速此域名");
-                }
-            }
-        }
-
-        /// <summary>
-        /// 获取本机所有ip
-        /// </summary> 
-        /// <returns></returns>
-        private static IEnumerable<IPAddress> GetLocalMachineIPAddress()
-        {
-            foreach (var item in IPGlobalProperties.GetIPGlobalProperties().GetUnicastAddresses())
-            {
-                yield return item.Address;
+                value = new HostsRecord(items[1], address);
+                return true;
             }
         }
     }