esm: use undici/fetch data url parser

lib/internal/data_url.js

@@ -0,0 +1,352 @@
+'use strict';
+
+const {
+ RegExpPrototypeExec,
+ RegExpPrototypeSymbolReplace,
+ StringFromCharCodeApply,
+ StringPrototypeCharCodeAt,
+ StringPrototypeIndexOf,
+ StringPrototypeSlice,
+ TypedArrayPrototypeSubarray,
+ Uint8Array,
+} = primordials;
+
+const assert = require('internal/assert');
+const { Buffer } = require('buffer');
+const { MIMEType } = require('internal/mime');
+
+let encoder;
+function lazyEncoder() {
+ if (encoder === undefined) {
+ const { TextEncoder } = require('internal/encoding');
+ encoder = new TextEncoder();
+ }
+
+ return encoder;
+}
+
+const ASCII_WHITESPACE_REPLACE_REGEX = /[\u0009\u000A\u000C\u000D\u0020]/g // eslint-disable-line
+
+// https://fetch.spec.whatwg.org/#data-url-processor
+/** @param {URL} dataURL */
+function dataURLProcessor(dataURL) {
+ // 1. Assert: dataURL's scheme is "data".
+ assert(dataURL.protocol === 'data:');
+
+ // 2. Let input be the result of running the URL
+ // serializer on dataURL with exclude fragment
+ // set to true.
+ let input = URLSerializer(dataURL, true);
+
+ // 3. Remove the leading "data:" string from input.
+ input = StringPrototypeSlice(input, 5);
+
+ // 4. Let position point at the start of input.
+ const position = { position: 0 };
+
+ // 5. Let mimeType be the result of collecting a
+ // sequence of code points that are not equal
+ // to U+002C (,), given position.
+ let mimeType = collectASequenceOfCodePointsFast(
+ ',',
+ input,
+ position,
+ );
+
+ // 6. Strip leading and trailing ASCII whitespace
+ // from mimeType.
+ // Undici implementation note: we need to store the
+ // length because if the mimetype has spaces removed,
+ // the wrong amount will be sliced from the input in
+ // step #9
+ const mimeTypeLength = mimeType.length;
+ mimeType = removeASCIIWhitespace(mimeType, true, true);
+
+ // 7. If position is past the end of input, then
+ // return failure
+ if (position.position >= input.length) {
+ return 'failure';
+ }
+
+ // 8. Advance position by 1.
+ position.position++;
+
+ // 9. Let encodedBody be the remainder of input.
+ const encodedBody = StringPrototypeSlice(input, mimeTypeLength + 1);
+
+ // 10. Let body be the percent-decoding of encodedBody.
+ let body = stringPercentDecode(encodedBody);
+
+ // 11. If mimeType ends with U+003B (;), followed by
+ // zero or more U+0020 SPACE, followed by an ASCII
+ // case-insensitive match for "base64", then:
+ if (RegExpPrototypeExec(/;(\u0020){0,}base64$/i, mimeType) !== null) {
+ // 1. Let stringBody be the isomorphic decode of body.
+ const stringBody = isomorphicDecode(body);
+
+ // 2. Set body to the forgiving-base64 decode of
+ // stringBody.
+ body = forgivingBase64(stringBody);
+
+ // 3. If body is failure, then return failure.
+ if (body === 'failure') {
+ return 'failure';
+ }
+
+ // 4. Remove the last 6 code points from mimeType.
+ mimeType = StringPrototypeSlice(mimeType, 0, -6);
+
+ // 5. Remove trailing U+0020 SPACE code points from mimeType,
+ // if any.
+ mimeType = RegExpPrototypeSymbolReplace(/(\u0020)+$/, mimeType, '');
+
+ // 6. Remove the last U+003B (;) code point from mimeType.
+ mimeType = StringPrototypeSlice(mimeType, 0, -1);
+ }
+
+ // 12. If mimeType starts with U+003B (;), then prepend
+ // "text/plain" to mimeType.
+ if (mimeType[0] === ';') {
+ mimeType = 'text/plain' + mimeType;
+ }
+
+ // 13. Let mimeTypeRecord be the result of parsing
+ // mimeType.
+ // 14. If mimeTypeRecord is failure, then set
+ // mimeTypeRecord to text/plain;charset=US-ASCII.
+ let mimeTypeRecord;
+
+ try {
+ mimeTypeRecord = new MIMEType(mimeType);
+ } catch {
+ mimeTypeRecord = new MIMEType('text/plain;charset=US-ASCII');
+ }
+
+ // 15. Return a new data: URL struct whose MIME
+ // type is mimeTypeRecord and body is body.
+ // https://fetch.spec.whatwg.org/#data-url-struct
+ return { mimeType: mimeTypeRecord, body };
+}
+
+// https://url.spec.whatwg.org/#concept-url-serializer
+/**
+ * @param {URL} url
+ * @param {boolean} excludeFragment
+ */
+function URLSerializer(url, excludeFragment = false) {
+ const { href } = url;
+
+ if (!excludeFragment) {
+ return href;
+ }
+
+ const hashLength = url.hash.length;
+ const serialized = hashLength === 0 ? href : StringPrototypeSlice(href, 0, href.length - hashLength);
+
+ if (!hashLength && href[href.length - 1] === '#') {
+ return StringPrototypeSlice(serialized, 0, -1);
+ }
+
+ return serialized;
+}
+
+/**
+ * A faster collectASequenceOfCodePoints that only works when comparing a single character.
+ * @param {string} char
+ * @param {string} input
+ * @param {{ position: number }} position
+ */
+function collectASequenceOfCodePointsFast(char, input, position) {
+ const idx = StringPrototypeIndexOf(input, char, position.position);
+ const start = position.position;
+
+ if (idx === -1) {
+ position.position = input.length;
+ return StringPrototypeSlice(input, start);
+ }
+
+ position.position = idx;
+ return StringPrototypeSlice(input, start, position.position);
+}
+
+// https://url.spec.whatwg.org/#string-percent-decode
+/** @param {string} input */
+function stringPercentDecode(input) {
+ // 1. Let bytes be the UTF-8 encoding of input.
+ const bytes = lazyEncoder().encode(input);
+
+ // 2. Return the percent-decoding of bytes.
+ return percentDecode(bytes);
+}
+
+/**
+ * @param {number} byte
+ */
+function isHexCharByte(byte) {
+ // 0-9 A-F a-f
+ return (byte >= 0x30 && byte <= 0x39) || (byte >= 0x41 && byte <= 0x46) || (byte >= 0x61 && byte <= 0x66);
+}
+
+/**
+ * @param {number} byte
+ */
+function hexByteToNumber(byte) {
+ return (
+ // 0-9
+ byte >= 0x30 && byte <= 0x39 ?
+ (byte - 48) :
+ // Convert to uppercase
+ // ((byte & 0xDF) - 65) + 10
+ ((byte & 0xDF) - 55)
+ );
+}
+
+// https://url.spec.whatwg.org/#percent-decode
+/** @param {Uint8Array} input */
+function percentDecode(input) {
+ const length = input.length;
+ // 1. Let output be an empty byte sequence.
+ /** @type {Uint8Array} */
+ const output = new Uint8Array(length);
+ let j = 0;
+ // 2. For each byte byte in input:
+ for (let i = 0; i < length; ++i) {
+ const byte = input[i];
+
+ // 1. If byte is not 0x25 (%), then append byte to output.
+ if (byte !== 0x25) {
+ output[j++] = byte;
+
+ // 2. Otherwise, if byte is 0x25 (%) and the next two bytes
+ // after byte in input are not in the ranges
+ // 0x30 (0) to 0x39 (9), 0x41 (A) to 0x46 (F),
+ // and 0x61 (a) to 0x66 (f), all inclusive, append byte
+ // to output.
+ } else if (
+ byte === 0x25 &&
+ !(isHexCharByte(input[i + 1]) && isHexCharByte(input[i + 2]))
+ ) {
+ output[j++] = 0x25;
+
+ // 3. Otherwise:
+ } else {
+ // 1. Let bytePoint be the two bytes after byte in input,
+ // decoded, and then interpreted as hexadecimal number.
+ // 2. Append a byte whose value is bytePoint to output.
+ output[j++] = (hexByteToNumber(input[i + 1]) << 4) | hexByteToNumber(input[i + 2]);
+
+ // 3. Skip the next two bytes in input.
+ i += 2;
+ }
+ }
+
+ // 3. Return output.
+ return length === j ? output : TypedArrayPrototypeSubarray(output, 0, j);
+}
+
+// https://infra.spec.whatwg.org/#forgiving-base64-decode
+/** @param {string} data */
+function forgivingBase64(data) {
+ // 1. Remove all ASCII whitespace from data.
+ data = RegExpPrototypeSymbolReplace(ASCII_WHITESPACE_REPLACE_REGEX, data, '');
+
+ let dataLength = data.length;
+ // 2. If data's code point length divides by 4 leaving
+ // no remainder, then:
+ if (dataLength % 4 === 0) {
+ // 1. If data ends with one or two U+003D (=) code points,
+ // then remove them from data.
+ if (data[dataLength - 1] === '=') {
+ --dataLength;
+ if (data[dataLength - 1] === '=') {
+ --dataLength;
+ }
+ }
+ }
+
+ // 3. If data's code point length divides by 4 leaving
+ // a remainder of 1, then return failure.
+ if (dataLength % 4 === 1) {
+ return 'failure';
+ }
+
+ // 4. If data contains a code point that is not one of
+ // U+002B (+)
+ // U+002F (/)
+ // ASCII alphanumeric
+ // then return failure.
+ if (RegExpPrototypeExec(/[^+/0-9A-Za-z]/, data.length === dataLength ? data : StringPrototypeSlice(data, 0, dataLength)) !== null) {
+ return 'failure';
+ }
+
+ const buffer = Buffer.from(data, 'base64');
+ return new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength);
+}
+
+/**
+ * @see https://infra.spec.whatwg.org/#ascii-whitespace
+ * @param {number} char
+ */
+function isASCIIWhitespace(char) {
+ // "\r\n\t\f "
+ return char === 0x00d || char === 0x00a || char === 0x009 || char === 0x00c || char === 0x020;
+}
+
+/**
+ * @see https://infra.spec.whatwg.org/#strip-leading-and-trailing-ascii-whitespace
+ * @param {string} str
+ * @param {boolean} [leading=true]
+ * @param {boolean} [trailing=true]
+ */
+function removeASCIIWhitespace(str, leading = true, trailing = true) {
+ return removeChars(str, leading, trailing, isASCIIWhitespace);
+}
+
+/**
+ * @param {string} str
+ * @param {boolean} leading
+ * @param {boolean} trailing
+ * @param {(charCode: number) => boolean} predicate
+ */
+function removeChars(str, leading, trailing, predicate) {
+ let lead = 0;
+ let trail = str.length - 1;
+
+ if (leading) {
+ while (lead < str.length && predicate(StringPrototypeCharCodeAt(str, lead))) lead++;
+ }
+
+ if (trailing) {
+ while (trail > 0 && predicate(StringPrototypeCharCodeAt(str, trail))) trail--;
+ }
+
+ return lead === 0 && trail === str.length - 1 ? str : StringPrototypeSlice(str, lead, trail + 1);
+}
+
+/**
+ * @see https://infra.spec.whatwg.org/#isomorphic-decode
+ * @param {Uint8Array} input
+ * @returns {string}
+ */
+function isomorphicDecode(input) {
+ // 1. To isomorphic decode a byte sequence input, return a string whose code point
+ // length is equal to input's length and whose code points have the same values
+ // as the values of input's bytes, in the same order.
+ const length = input.length;
+ if ((2 << 15) - 1 > length) {
+ return StringFromCharCodeApply(input);
+ }
+ let result = ''; let i = 0;
+ let addition = (2 << 15) - 1;
+ while (i < length) {
+ if (i + addition > length) {
+ addition = length - i;
+ }
+ result += StringFromCharCodeApply(TypedArrayPrototypeSubarray(input, i, i += addition));
+ }
+ return result;
+}
+
+module.exports = {
+ dataURLProcessor,
+};