JavaScriptTestEncoder.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.IO;
using System.Text.Encodings.Web;
using Microsoft.AspNetCore.Shared;

namespace Microsoft.Extensions.WebEncoders.Testing;

/// <summary>
/// <see cref="JavaScriptEncoder"/> used for unit testing. This encoder does not perform any encoding and should not be used in application code.
/// </summary>
public class JavaScriptTestEncoder : JavaScriptEncoder
{
    /// <inheritdoc />
    public override int MaxOutputCharactersPerInputCharacter
    {
        get { return 1; }
    }

    /// <inheritdoc />
    public override string Encode(string value)
    {
        ArgumentNullThrowHelper.ThrowIfNull(value);

        if (value.Length == 0)
        {
            return string.Empty;
        }

        return $"JavaScriptEncode[[{value}]]";
    }

    /// <inheritdoc />
    public override void Encode(TextWriter output, char[] value, int startIndex, int characterCount)
    {
        ArgumentNullThrowHelper.ThrowIfNull(output);
        ArgumentNullThrowHelper.ThrowIfNull(value);

        if (characterCount == 0)
        {
            return;
        }

        output.Write("JavaScriptEncode[[");
        output.Write(value, startIndex, characterCount);
        output.Write("]]");
    }

    /// <inheritdoc />
    public override void Encode(TextWriter output, string value, int startIndex, int characterCount)
    {
        ArgumentNullThrowHelper.ThrowIfNull(output);
        ArgumentNullThrowHelper.ThrowIfNull(value);

        if (characterCount == 0)
        {
            return;
        }

        output.Write("JavaScriptEncode[[");
#if NETFRAMEWORK || NETSTANDARD
        output.Write(value.Substring(startIndex, characterCount));
#else
        output.Write(value.AsSpan(startIndex, characterCount));
#endif
        output.Write("]]");
    }

    /// <inheritdoc />
    public override bool WillEncode(int unicodeScalar)
    {
        return false;
    }

    /// <inheritdoc />
    public override unsafe int FindFirstCharacterToEncode(char* text, int textLength)
    {
        return -1;
    }

    /// <inheritdoc />
    public override unsafe bool TryEncodeUnicodeScalar(
        int unicodeScalar,
        char* buffer,
        int bufferLength,
        out int numberOfCharactersWritten)
    {
        if (buffer == null)
        {
            throw new ArgumentNullException(nameof(buffer));
        }

        numberOfCharactersWritten = 0;
        return false;
    }
}