sebastienros.jint/Jint/Runtime/Environments/JintEnvironment.cs

using System.Diagnostics.CodeAnalysis;
using Jint.Native;
using Jint.Native.Function;
using Jint.Native.Object;

namespace Jint.Runtime.Environments;

internal static class JintEnvironment
{
    internal static bool TryGetIdentifierEnvironmentWithBinding(
        Environment env,
        Environment.BindingName name,
        [NotNullWhen(true)] out Environment? record)
    {
        record = env;

        if (env._outerEnv is null)
        {
            return env.HasBinding(name);
        }

        while (record is not null)
        {
            if (record.HasBinding(name))
            {
                return true;
            }

            record = record._outerEnv;
        }

        return false;
    }

    internal static bool TryGetIdentifierEnvironmentWithBindingValue(
        Environment env,
        Environment.BindingName name,
        [NotNullWhen(true)] out Environment? record,
        [NotNullWhen(true)] out JsValue? value)
    {
        record = env;
        value = default;

        if (env._outerEnv is null)
        {
            return ((GlobalEnvironment) env).TryGetBinding(name, out value);
        }

        while (record is not null)
        {
            if (record.TryGetBinding(name, out value))
            {
                return true;
            }

            record = record._outerEnv;
        }

        return false;
    }

    /// <summary>
    /// https://tc39.es/ecma262/#sec-newdeclarativeenvironment
    /// </summary>
    internal static DeclarativeEnvironment NewDeclarativeEnvironment(Engine engine, Environment? outer, bool catchEnvironment = false)
    {
        return new DeclarativeEnvironment(engine, catchEnvironment)
        {
            _outerEnv = outer
        };
    }

    /// <summary>
    /// https://tc39.es/ecma262/#sec-newfunctionenvironment
    /// </summary>
    internal static FunctionEnvironment NewFunctionEnvironment(Engine engine, Function f, JsValue newTarget)
    {
        return new FunctionEnvironment(engine, f, newTarget)
        {
            _outerEnv = f._environment
        };
    }

    /// <summary>
    /// https://tc39.es/ecma262/#sec-newglobalenvironment
    /// </summary>
    internal static GlobalEnvironment NewGlobalEnvironment(Engine engine, ObjectInstance objectInstance, JsValue thisValue)
    {
        return new GlobalEnvironment(engine, objectInstance)
        {
            _outerEnv = null
        };
    }

    /// <summary>
    /// https://tc39.es/ecma262/#sec-newobjectenvironment
    /// </summary>
    internal static ObjectEnvironment NewObjectEnvironment(Engine engine, ObjectInstance objectInstance, Environment outer, bool provideThis, bool withEnvironment = false)
    {
        return new ObjectEnvironment(engine, objectInstance, provideThis, withEnvironment)
        {
            _outerEnv = outer
        };
    }

    /// <summary>
    /// https://tc39.es/ecma262/#sec-newprivateenvironment
    /// </summary>
    internal static PrivateEnvironment NewPrivateEnvironment(Engine engine, PrivateEnvironment? outerPriv)
    {
        return new PrivateEnvironment(outerPriv);
    }

    /// <summary>
    /// https://tc39.es/ecma262/#sec-newmoduleenvironment
    /// </summary>
    internal static ModuleEnvironment NewModuleEnvironment(Engine engine, Environment outer)
    {
        return new ModuleEnvironment(engine)
        {
            _outerEnv = outer
        };
    }
}