🐍 Add JsonSnakeCaseNamingPolicy

- For the use of online configuration generation
- Source: dotnet/corefx#40003
- See also: dotnet/runtime#782

shadowsocks-uri-generator/JsonSnakeCaseNamingPolicy.cs

@@ -0,0 +1,87 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Source: https://github.com/dotnet/corefx/pull/40003
+// See also: https://github.com/dotnet/runtime/issues/782
+
+using System;
+using System.Text;
+using System.Text.Json;
+
+namespace shadowsocks_uri_generator
+{
+ public class JsonSnakeCaseNamingPolicy : JsonNamingPolicy
+ {
+ internal enum SnakeCaseState
+ {
+ Start,
+ Lower,
+ Upper,
+ NewWord
+ }
+
+ public override string ConvertName(string name)
+ {
+ if (string.IsNullOrEmpty(name))
+ {
+ return name;
+ }
+
+ var sb = new StringBuilder();
+ var state = SnakeCaseState.Start;
+
+ var nameSpan = name.AsSpan();
+
+ for (int i = 0; i < nameSpan.Length; i++)
+ {
+ if (nameSpan[i] == ' ')
+ {
+ if (state != SnakeCaseState.Start)
+ {
+ state = SnakeCaseState.NewWord;
+ }
+ }
+ else if (char.IsUpper(nameSpan[i]))
+ {
+ switch (state)
+ {
+ case SnakeCaseState.Upper:
+ bool hasNext = (i + 1 < nameSpan.Length);
+ if (i > 0 && hasNext)
+ {
+ char nextChar = nameSpan[i + 1];
+ if (!char.IsUpper(nextChar) && nextChar != '_')
+ {
+ sb.Append('_');
+ }
+ }
+ break;
+ case SnakeCaseState.Lower:
+ case SnakeCaseState.NewWord:
+ sb.Append('_');
+ break;
+ }
+ sb.Append(char.ToLowerInvariant(nameSpan[i]));
+ state = SnakeCaseState.Upper;
+ }
+ else if (nameSpan[i] == '_')
+ {
+ sb.Append('_');
+ state = SnakeCaseState.Start;
+ }
+ else
+ {
+ if (state == SnakeCaseState.NewWord)
+ {
+ sb.Append('_');
+ }
+
+ sb.Append(nameSpan[i]);
+ state = SnakeCaseState.Lower;
+ }
+ }
+
+ return sb.ToString();
+ }
+ }
+}