RegexLWCGCompiler.cs

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using System.Reflection;
using System.Reflection.Emit;
using System.Threading;
 
namespace System.Text.RegularExpressions;
 
internal sealed class RegexLWCGCompiler : RegexCompiler
{
    private static readonly bool s_includePatternInName = Environment.GetEnvironmentVariable("DOTNET_SYSTEM_TEXT_REGULAREXPRESSIONS_PATTERNINNAME") == "1";
 
    private static readonly Type[] s_paramTypes = new Type[1] { typeof(RegexRunner) };
 
    private static int s_regexCount;
 
    public RegexLWCGCompiler()
        : base(persistsAssembly: false)
    {
    }
 
    public RegexRunnerFactory FactoryInstanceFromCode(string pattern, RegexCode code, RegexOptions options, bool hasTimeout)
    {
        _code = code;
        _codes = code.Codes;
        _strings = code.Strings;
        _leadingCharClasses = code.LeadingCharClasses;
        _boyerMoorePrefix = code.BoyerMoorePrefix;
        _leadingAnchor = code.LeadingAnchor;
        _trackcount = code.TrackCount;
        _options = options;
        _hasTimeout = hasTimeout;
        uint value = (uint)Interlocked.Increment(ref s_regexCount);
        string value2 = string.Empty;
        if (s_includePatternInName)
        {
            value2 = "_" + ((pattern.Length > 100) ? pattern.AsSpan(0, 100) : ((ReadOnlySpan<char>)pattern));
        }
        DynamicMethod goMethod = DefineDynamicMethod($"Regex{value}_Go{value2}", null, typeof(CompiledRegexRunner));
        GenerateGo();
        DynamicMethod findFirstCharMethod = DefineDynamicMethod($"Regex{value}_FindFirstChar{value2}", typeof(bool), typeof(CompiledRegexRunner));
        GenerateFindFirstChar();
        return new CompiledRegexRunnerFactory(goMethod, findFirstCharMethod, _trackcount);
    }
 
    private DynamicMethod DefineDynamicMethod(string methname, Type returntype, Type hostType)
    {
        DynamicMethod dynamicMethod = new DynamicMethod(methname, MethodAttributes.Public | MethodAttributes.Static, CallingConventions.Standard, returntype, s_paramTypes, hostType, skipVisibility: false);
        _ilg = dynamicMethod.GetILGenerator();
        return dynamicMethod;
    }
}