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[release/3.1] Use Sse2 instrinsics to optimize NeedsEscaping/FindFirstCharToEncode for all built-in JavaScriptEncoders #42030
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,271 @@ | ||
| // Licensed to the .NET Foundation under one or more agreements. | ||
| // The .NET Foundation licenses this file to you under the MIT license. | ||
| // See the LICENSE file in the project root for more information. | ||
|
|
||
| using System.Buffers; | ||
| using System.Diagnostics; | ||
| using System.Runtime.CompilerServices; | ||
| using System.Text.Internal; | ||
| using System.Text.Unicode; | ||
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| #if BUILDING_INBOX_LIBRARY | ||
| using System.Runtime.Intrinsics; | ||
| using System.Runtime.Intrinsics.X86; | ||
| #endif | ||
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| namespace System.Text.Encodings.Web | ||
| { | ||
| internal sealed class DefaultJavaScriptEncoder : JavaScriptEncoder | ||
| { | ||
| private readonly AllowedCharactersBitmap _allowedCharacters; | ||
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| private readonly int[] _asciiNeedsEscaping = new int[0x80]; | ||
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| public DefaultJavaScriptEncoder(TextEncoderSettings filter) | ||
| { | ||
| if (filter == null) | ||
| { | ||
| throw new ArgumentNullException(nameof(filter)); | ||
| } | ||
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| _allowedCharacters = filter.GetAllowedCharacters(); | ||
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| // Forbid codepoints which aren't mapped to characters or which are otherwise always disallowed | ||
| // (includes categories Cc, Cs, Co, Cn, Zs [except U+0020 SPACE], Zl, Zp) | ||
| _allowedCharacters.ForbidUndefinedCharacters(); | ||
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| // Forbid characters that are special in HTML. | ||
| // Even though this is a not HTML encoder, | ||
| // it's unfortunately common for developers to | ||
| // forget to HTML-encode a string once it has been JS-encoded, | ||
| // so this offers extra protection. | ||
| DefaultHtmlEncoder.ForbidHtmlCharacters(_allowedCharacters); | ||
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| // '\' (U+005C REVERSE SOLIDUS) must always be escaped in Javascript / ECMAScript / JSON. | ||
| // '/' (U+002F SOLIDUS) is not Javascript / ECMAScript / JSON-sensitive so doesn't need to be escaped. | ||
| _allowedCharacters.ForbidCharacter('\\'); | ||
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| // '`' (U+0060 GRAVE ACCENT) is ECMAScript-sensitive (see ECMA-262). | ||
| _allowedCharacters.ForbidCharacter('`'); | ||
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| for (int i = 0; i < _asciiNeedsEscaping.Length; i++) | ||
| { | ||
| _asciiNeedsEscaping[i] = WillEncode(i) ? 1 : -1; | ||
| } | ||
| } | ||
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| public DefaultJavaScriptEncoder(params UnicodeRange[] allowedRanges) : this(new TextEncoderSettings(allowedRanges)) | ||
| { } | ||
|
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| [MethodImpl(MethodImplOptions.AggressiveInlining)] | ||
| public override bool WillEncode(int unicodeScalar) | ||
| { | ||
| if (UnicodeHelpers.IsSupplementaryCodePoint(unicodeScalar)) | ||
| { | ||
| return true; | ||
| } | ||
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| Debug.Assert(unicodeScalar >= char.MinValue && unicodeScalar <= char.MaxValue); | ||
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| return !_allowedCharacters.IsUnicodeScalarAllowed(unicodeScalar); | ||
| } | ||
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| [MethodImpl(MethodImplOptions.AggressiveInlining)] | ||
| public override unsafe int FindFirstCharacterToEncode(char* text, int textLength) | ||
| { | ||
| if (text == null) | ||
| { | ||
| throw new ArgumentNullException(nameof(text)); | ||
| } | ||
|
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| return _allowedCharacters.FindFirstCharacterToEncode(text, textLength); | ||
| } | ||
|
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| public override unsafe int FindFirstCharacterToEncodeUtf8(ReadOnlySpan<byte> utf8Text) | ||
| { | ||
| fixed (byte* ptr = utf8Text) | ||
| { | ||
| int idx = 0; | ||
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| #if BUILDING_INBOX_LIBRARY | ||
| if (Sse2.IsSupported) | ||
| { | ||
| sbyte* startingAddress = (sbyte*)ptr; | ||
| while (utf8Text.Length - 16 >= idx) | ||
| { | ||
| Debug.Assert(startingAddress >= ptr && startingAddress <= (ptr + utf8Text.Length - 16)); | ||
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| // Load the next 16 bytes. | ||
| Vector128<sbyte> sourceValue = Sse2.LoadVector128(startingAddress); | ||
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| Vector128<sbyte> mask = Sse2Helper.CreateAsciiMask(sourceValue); | ||
| int index = Sse2.MoveMask(mask); | ||
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| if (index != 0) | ||
| { | ||
| // At least one of the following 16 bytes is non-ASCII. | ||
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| int processNextSixteen = idx + 16; | ||
| Debug.Assert(processNextSixteen <= utf8Text.Length); | ||
|
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| while (idx < processNextSixteen) | ||
| { | ||
| Debug.Assert((ptr + idx) <= (ptr + utf8Text.Length)); | ||
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| if (UnicodeUtility.IsAsciiCodePoint(ptr[idx])) | ||
| { | ||
| if (DoesAsciiNeedEncoding(ptr[idx]) == 1) | ||
| { | ||
| goto Return; | ||
| } | ||
| idx++; | ||
| } | ||
| else | ||
| { | ||
| OperationStatus opStatus = UnicodeHelpers.DecodeScalarValueFromUtf8(utf8Text.Slice(idx), out uint nextScalarValue, out int utf8BytesConsumedForScalar); | ||
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| Debug.Assert(nextScalarValue <= int.MaxValue); | ||
| if (opStatus != OperationStatus.Done || WillEncode((int)nextScalarValue)) | ||
| { | ||
| goto Return; | ||
| } | ||
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| Debug.Assert(opStatus == OperationStatus.Done); | ||
| idx += utf8BytesConsumedForScalar; | ||
| } | ||
| } | ||
| } | ||
| else | ||
| { | ||
| if (DoesAsciiNeedEncoding(ptr[idx]) == 1 | ||
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| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
|
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| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
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| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
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| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1 | ||
| || DoesAsciiNeedEncoding(ptr[++idx]) == 1) | ||
| { | ||
| goto Return; | ||
| } | ||
| idx++; | ||
| } | ||
| startingAddress = (sbyte*)ptr + idx; | ||
| } | ||
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| // Process the remaining bytes. | ||
| Debug.Assert(utf8Text.Length - idx < 16); | ||
| } | ||
| #endif | ||
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| while (idx < utf8Text.Length) | ||
| { | ||
| Debug.Assert((ptr + idx) <= (ptr + utf8Text.Length)); | ||
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| if (UnicodeUtility.IsAsciiCodePoint(ptr[idx])) | ||
| { | ||
| if (DoesAsciiNeedEncoding(ptr[idx]) == 1) | ||
| { | ||
| goto Return; | ||
| } | ||
| idx++; | ||
| } | ||
| else | ||
| { | ||
| OperationStatus opStatus = UnicodeHelpers.DecodeScalarValueFromUtf8(utf8Text.Slice(idx), out uint nextScalarValue, out int utf8BytesConsumedForScalar); | ||
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| Debug.Assert(nextScalarValue <= int.MaxValue); | ||
| if (opStatus != OperationStatus.Done || WillEncode((int)nextScalarValue)) | ||
| { | ||
| goto Return; | ||
| } | ||
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| Debug.Assert(opStatus == OperationStatus.Done); | ||
| idx += utf8BytesConsumedForScalar; | ||
| } | ||
| } | ||
|
Member
There was a problem hiding this comment. does it make sense to add assert after this line idx == utf8Text.Length?
Author
There was a problem hiding this comment. The while loop condition already guards for |
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| idx = -1; // All bytes are allowed. | ||
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| Return: | ||
| return idx; | ||
| } | ||
| } | ||
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| [MethodImpl(MethodImplOptions.AggressiveInlining)] | ||
| private int DoesAsciiNeedEncoding(byte value) | ||
| { | ||
| Debug.Assert(value <= 0x7F); | ||
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| int needsEscaping = _asciiNeedsEscaping[value]; | ||
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| Debug.Assert(needsEscaping == 1 || needsEscaping == -1); | ||
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| return needsEscaping; | ||
| } | ||
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| // The worst case encoding is 6 output chars per input char: [input] U+FFFF -> [output] "\uFFFF" | ||
| // We don't need to worry about astral code points since they're represented as encoded | ||
| // surrogate pairs in the output. | ||
| public override int MaxOutputCharactersPerInputCharacter => 12; // "\uFFFF\uFFFF" is the longest encoded form | ||
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| private static readonly char[] s_b = new char[] { '\\', 'b' }; | ||
| private static readonly char[] s_t = new char[] { '\\', 't' }; | ||
| private static readonly char[] s_n = new char[] { '\\', 'n' }; | ||
| private static readonly char[] s_f = new char[] { '\\', 'f' }; | ||
| private static readonly char[] s_r = new char[] { '\\', 'r' }; | ||
| private static readonly char[] s_back = new char[] { '\\', '\\' }; | ||
|
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| // Writes a scalar value as a JavaScript-escaped character (or sequence of characters). | ||
| // See ECMA-262, Sec. 7.8.4, and ECMA-404, Sec. 9 | ||
| // http://www.ecma-international.org/ecma-262/5.1/#sec-7.8.4 | ||
| // http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf | ||
| public override unsafe bool TryEncodeUnicodeScalar(int unicodeScalar, char* buffer, int bufferLength, out int numberOfCharactersWritten) | ||
| { | ||
| if (buffer == null) | ||
| { | ||
| throw new ArgumentNullException(nameof(buffer)); | ||
| } | ||
| // ECMA-262 allows encoding U+000B as "\v", but ECMA-404 does not. | ||
| // Both ECMA-262 and ECMA-404 allow encoding U+002F SOLIDUS as "\/" | ||
| // (in ECMA-262 this character is a NonEscape character); however, we | ||
| // don't encode SOLIDUS by default unless the caller has provided an | ||
| // explicit bitmap which does not contain it. In this case we'll assume | ||
| // that the caller didn't want a SOLIDUS written to the output at all, | ||
| // so it should be written using "\u002F" encoding. | ||
| // HTML-specific characters (including apostrophe and quotes) will | ||
| // be written out as numeric entities for defense-in-depth. | ||
| // See UnicodeEncoderBase ctor comments for more info. | ||
|
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| if (!WillEncode(unicodeScalar)) | ||
| { | ||
| return TryWriteScalarAsChar(unicodeScalar, buffer, bufferLength, out numberOfCharactersWritten); | ||
| } | ||
|
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| char[] toCopy; | ||
| switch (unicodeScalar) | ||
| { | ||
| case '\b': toCopy = s_b; break; | ||
| case '\t': toCopy = s_t; break; | ||
| case '\n': toCopy = s_n; break; | ||
| case '\f': toCopy = s_f; break; | ||
| case '\r': toCopy = s_r; break; | ||
| case '\\': toCopy = s_back; break; | ||
| default: return JavaScriptEncoderHelper.TryWriteEncodedScalarAsNumericEntity(unicodeScalar, buffer, bufferLength, out numberOfCharactersWritten); | ||
| } | ||
| return TryCopyCharacters(toCopy, buffer, bufferLength, out numberOfCharactersWritten); | ||
| } | ||
| } | ||
| } | ||
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Most of the changes in this file are copy-paste from
JavaScriptEncoder.csinto a separate file and don't change the existing logic.