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string_decoder: align UTF-8 handling with V8

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V8 5.5 changed how invalid characters are handled and it now appears
to follow the WHATWG Encoding standard, where all of an invalid
character's bytes are replaced by a single replacement character
(\ufffd) instead of replacing each invalid byte with separate
replacement characters.

Example: the byte sequence 0xF0,0xB8,0x41 is decoded as '\ufffdA' in
V8 5.5, but is decoded as '\ufffd\ufffdA' in previous versions of V8.

PR-URL: https://github.com/nodejs/node/pull/9618
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
This commit is contained in:
Brian White 2016-12-29 12:02:31 -05:00 committed by Michaël Zasso
parent 007386ee81
commit 24ef1e6775
3 changed files with 16 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
lib/string_decoder.js
View File

@ -81,7 +81,7 @@ StringDecoder.prototype.fillLast = function(buf) {
};
// Checks the type of a UTF-8 byte, whether it's ASCII, a leading byte, or a
// continuation byte.
// continuation byte. If an invalid byte is detected, -2 is returned.
function utf8CheckByte(byte) {
if (byte <= 0x7F)
return 0;
@ -91,7 +91,7 @@ function utf8CheckByte(byte) {
return 3;
else if (byte >> 3 === 0x1E)
return 4;
return -1;
return (byte >> 6 === 0x02 ? -1 : -2);
}
// Checks at most 3 bytes at the end of a Buffer in order to detect an
@ -107,7 +107,7 @@ function utf8CheckIncomplete(self, buf, i) {
self.lastNeed = nb - 1;
return nb;
}
if (--j < i)
if (--j < i || nb === -2)
return 0;
nb = utf8CheckByte(buf[j]);
if (nb >= 0) {
@ -115,7 +115,7 @@ function utf8CheckIncomplete(self, buf, i) {
self.lastNeed = nb - 2;
return nb;
}
if (--j < i)
if (--j < i || nb === -2)
return 0;
nb = utf8CheckByte(buf[j]);
if (nb >= 0) {
@ -133,7 +133,7 @@ function utf8CheckIncomplete(self, buf, i) {
// Validates as many continuation bytes for a multi-byte UTF-8 character as
// needed or are available. If we see a non-continuation byte where we expect
// one, we "replace" the validated continuation bytes we've seen so far with
// UTF-8 replacement characters ('\ufffd'), to match v8's UTF-8 decoding
// a single UTF-8 replacement character ('\ufffd'), to match v8's UTF-8 decoding
// behavior. The continuation byte check is included three times in the case
// where all of the continuation bytes for a character exist in the same buffer.
// It is also done this way as a slight performance increase instead of using a
@ -141,17 +141,17 @@ function utf8CheckIncomplete(self, buf, i) {
function utf8CheckExtraBytes(self, buf, p) {
if ((buf[0] & 0xC0) !== 0x80) {
self.lastNeed = 0;
return '\ufffd'.repeat(p);
return '\ufffd';
}
if (self.lastNeed > 1 && buf.length > 1) {
if ((buf[1] & 0xC0) !== 0x80) {
self.lastNeed = 1;
return '\ufffd'.repeat(p + 1);
return '\ufffd';
}
if (self.lastNeed > 2 && buf.length > 2) {
if ((buf[2] & 0xC0) !== 0x80) {
self.lastNeed = 2;
return '\ufffd'.repeat(p + 2);
return '\ufffd';
}
}
}
@ -184,12 +184,12 @@ function utf8Text(buf, i) {
return buf.toString('utf8', i, end);
}
// For UTF-8, a replacement character for each buffered byte of a (partial)
// character needs to be added to the output.
// For UTF-8, a replacement character is added when ending on a partial
// character.
function utf8End(buf) {
const r = (buf && buf.length ? this.write(buf) : '');
if (this.lastNeed)
return r + '\ufffd'.repeat(this.lastTotal - this.lastNeed);
return r + '\ufffd';
return r;
}

7
test/parallel/test-string-decoder-end.js
View File

@ -18,8 +18,6 @@ for (let i = 1; i <= 16; i++) {
encodings.forEach(testEncoding);
console.log('ok');
function testEncoding(encoding) {
bufs.forEach((buf) => {
testBuf(encoding, buf);
@ -27,8 +25,6 @@ function testEncoding(encoding) {
}
function testBuf(encoding, buf) {
console.error('# %s', encoding, buf);
// write one byte at a time.
let s = new SD(encoding);
let res1 = '';
@ -46,9 +42,6 @@ function testBuf(encoding, buf) {
// .toString() on the buffer
const res3 = buf.toString(encoding);
console.log('expect=%j', res3);
console.log('res1=%j', res1);
console.log('res2=%j', res2);
assert.strictEqual(res1, res3, 'one byte at a time should match toString');
assert.strictEqual(res2, res3, 'all bytes at once should match toString');
}

15
test/parallel/test-string-decoder.js
View File

@ -8,8 +8,6 @@ const StringDecoder = require('string_decoder').StringDecoder;
let decoder = new StringDecoder();
assert.strictEqual(decoder.encoding, 'utf8');
process.stdout.write('scanning ');
// UTF-8
test('utf-8', Buffer.from('$', 'utf-8'), '$');
test('utf-8', Buffer.from('¢', 'utf-8'), '¢');
@ -42,15 +40,15 @@ test('utf-8', Buffer.from('C9B5A941', 'hex'), '\u0275\ufffdA');
test('utf-8', Buffer.from('E2', 'hex'), '\ufffd');
test('utf-8', Buffer.from('E241', 'hex'), '\ufffdA');
test('utf-8', Buffer.from('CCCCB8', 'hex'), '\ufffd\u0338');
test('utf-8', Buffer.from('F0B841', 'hex'), '\ufffd\ufffdA');
test('utf-8', Buffer.from('F0B841', 'hex'), '\ufffdA');
test('utf-8', Buffer.from('F1CCB8', 'hex'), '\ufffd\u0338');
test('utf-8', Buffer.from('F0FB00', 'hex'), '\ufffd\ufffd\0');
test('utf-8', Buffer.from('CCE2B8B8', 'hex'), '\ufffd\u2e38');
test('utf-8', Buffer.from('E2B8CCB8', 'hex'), '\ufffd\ufffd\u0338');
test('utf-8', Buffer.from('E2B8CCB8', 'hex'), '\ufffd\u0338');
test('utf-8', Buffer.from('E2FBCC01', 'hex'), '\ufffd\ufffd\ufffd\u0001');
test('utf-8', Buffer.from('EDA0B5EDB08D', 'hex'), // CESU-8 of U+1D40D
'\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd');
test('utf-8', Buffer.from('CCB8CDB9', 'hex'), '\u0338\u0379');
// CESU-8 of U+1D40D
test('utf-8', Buffer.from('EDA0B5EDB08D', 'hex'), '\ufffd\ufffd');
// UCS-2
test('ucs2', Buffer.from('ababc', 'ucs2'), 'ababc');
@ -58,8 +56,6 @@ test('ucs2', Buffer.from('ababc', 'ucs2'), 'ababc');
// UTF-16LE
test('utf16le', Buffer.from('3DD84DDC', 'hex'), '\ud83d\udc4d'); // thumbs up
console.log(' crayon!');
// Additional UTF-8 tests
decoder = new StringDecoder('utf8');
assert.strictEqual(decoder.write(Buffer.from('E1', 'hex')), '');
@ -67,7 +63,7 @@ assert.strictEqual(decoder.end(), '\ufffd');
decoder = new StringDecoder('utf8');
assert.strictEqual(decoder.write(Buffer.from('E18B', 'hex')), '');
assert.strictEqual(decoder.end(), '\ufffd\ufffd');
assert.strictEqual(decoder.end(), '\ufffd');
decoder = new StringDecoder('utf8');
assert.strictEqual(decoder.write(Buffer.from('\ufffd')), '\ufffd');
@ -131,7 +127,6 @@ function test(encoding, input, expected, singleSequence) {
output += decoder.write(input.slice(write[0], write[1]));
});
output += decoder.end();
process.stdout.write('.');
if (output !== expected) {
const message =
'Expected "' + unicodeEscape(expected) + '", ' +