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Add support for [AllowResizable] inputs in TextDeEncoder #58636

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69 changes: 36 additions & 33 deletions encoding/encodeInto.any.js
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Original file line number Diff line number Diff line change
Expand Up @@ -78,44 +78,47 @@
}
].forEach(destinationData => {
["ArrayBuffer", "SharedArrayBuffer"].forEach(arrayBufferOrSharedArrayBuffer => {
test(() => {
// Setup
const bufferLength = testData.destinationLength + destinationData.bufferIncrease;
const destinationOffset = destinationData.destinationOffset;
const destinationLength = testData.destinationLength;
const destinationFiller = destinationData.filler;
const encoder = new TextEncoder();
const buffer = createBuffer(arrayBufferOrSharedArrayBuffer, bufferLength);
const view = new Uint8Array(buffer, destinationOffset, destinationLength);
const fullView = new Uint8Array(buffer);
const control = new Array(bufferLength);
let byte = destinationFiller;
for (let i = 0; i < bufferLength; i++) {
if (destinationFiller === "random") {
byte = Math.floor(Math.random() * 256);
[false, true].forEach(resizable => {
test(() => {
// Setup
const bufferLength = testData.destinationLength + destinationData.bufferIncrease;
const destinationOffset = destinationData.destinationOffset;
const destinationLength = testData.destinationLength;
const destinationFiller = destinationData.filler;
const encoder = new TextEncoder();
const opts = resizable ? { maxByteLength: bufferLength } : undefined;
const buffer = createBuffer(arrayBufferOrSharedArrayBuffer, bufferLength, opts);
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@daxpedda daxpedda Mar 20, 2026

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Because we always want the max length to be the buffer length, I think this could be better solved on the createBuffer level. Maybe detect if opts is a boolean is an option?

const view = new Uint8Array(buffer, destinationOffset, destinationLength);
const fullView = new Uint8Array(buffer);
const control = new Array(bufferLength);
let byte = destinationFiller;
for (let i = 0; i < bufferLength; i++) {
if (destinationFiller === "random") {
byte = Math.floor(Math.random() * 256);
}
control[i] = byte;
fullView[i] = byte;
}
control[i] = byte;
fullView[i] = byte;
}

// It's happening
const result = encoder.encodeInto(testData.input, view);
// It's happening
const result = encoder.encodeInto(testData.input, view);

// Basics
assert_equals(view.byteLength, destinationLength);
assert_equals(view.length, destinationLength);
// Basics
assert_equals(view.byteLength, destinationLength);
assert_equals(view.length, destinationLength);

// Remainder
assert_equals(result.read, testData.read);
assert_equals(result.written, testData.written.length);
for (let i = 0; i < bufferLength; i++) {
if (i < destinationOffset || i >= (destinationOffset + testData.written.length)) {
assert_equals(fullView[i], control[i]);
} else {
assert_equals(fullView[i], testData.written[i - destinationOffset]);
// Remainder
assert_equals(result.read, testData.read);
assert_equals(result.written, testData.written.length);
for (let i = 0; i < bufferLength; i++) {
if (i < destinationOffset || i >= (destinationOffset + testData.written.length)) {
assert_equals(fullView[i], control[i]);
} else {
assert_equals(fullView[i], testData.written[i - destinationOffset]);
}
}
}
}, "encodeInto() into " + arrayBufferOrSharedArrayBuffer + " with " + testData.input + " and destination length " + testData.destinationLength + ", offset " + destinationData.destinationOffset + ", filler " + destinationData.filler);
}, "encodeInto() into " + (resizable ? "resizable " : "") + arrayBufferOrSharedArrayBuffer + " with " + testData.input + " and destination length " + testData.destinationLength + ", offset " + destinationData.destinationOffset + ", filler " + destinationData.filler);
})
})
});
});
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33 changes: 18 additions & 15 deletions encoding/textdecoder-copy.any.js
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Expand Up @@ -2,19 +2,22 @@
// META: script=/common/sab.js

["ArrayBuffer", "SharedArrayBuffer"].forEach(arrayBufferOrSharedArrayBuffer => {
test(() => {
const buf = createBuffer(arrayBufferOrSharedArrayBuffer, 2);
const view = new Uint8Array(buf);
const buf2 = createBuffer(arrayBufferOrSharedArrayBuffer, 2);
const view2 = new Uint8Array(buf2);
const decoder = new TextDecoder("utf-8");
view[0] = 0xEF;
view[1] = 0xBB;
view2[0] = 0xBF;
view2[1] = 0x40;
assert_equals(decoder.decode(buf, {stream:true}), "");
view[0] = 0x01;
view[1] = 0x02;
assert_equals(decoder.decode(buf2), "@");
}, "Modify buffer after passing it in (" + arrayBufferOrSharedArrayBuffer + ")");
[false, true].forEach(resizable => {
test(() => {
const opts = resizable ? { maxByteLength: 2 } : undefined;
const buf = createBuffer(arrayBufferOrSharedArrayBuffer, 2, opts);
const view = new Uint8Array(buf);
const buf2 = createBuffer(arrayBufferOrSharedArrayBuffer, 2, opts);
const view2 = new Uint8Array(buf2);
const decoder = new TextDecoder("utf-8");
view[0] = 0xEF;
view[1] = 0xBB;
view2[0] = 0xBF;
view2[1] = 0x40;
assert_equals(decoder.decode(buf, {stream:true}), "");
view[0] = 0x01;
view[1] = 0x02;
assert_equals(decoder.decode(buf2), "@");
}, "Modify buffer after passing it in (" + (resizable ? "resizable " : "") + arrayBufferOrSharedArrayBuffer + ")");
})
});
110 changes: 57 additions & 53 deletions encoding/textdecoder-streaming.any.js
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Expand Up @@ -19,71 +19,75 @@ var octets = {
};

["ArrayBuffer", "SharedArrayBuffer"].forEach((arrayBufferOrSharedArrayBuffer) => {
Object.keys(octets).forEach(function(encoding) {
for (var len = 1; len <= 5; ++len) {
test(function() {
var encoded = octets[encoding];
[false, true].forEach(resizable => {
Object.keys(octets).forEach(function(encoding) {
for (var len = 1; len <= 5; ++len) {
test(function() {
var encoded = octets[encoding];

var out = '';
var decoder = new TextDecoder(encoding);
for (var i = 0; i < encoded.length; i += len) {
var sub = [];
for (var j = i; j < encoded.length && j < i + len; ++j) {
sub.push(encoded[j]);
var out = '';
var decoder = new TextDecoder(encoding);
for (var i = 0; i < encoded.length; i += len) {
var sub = [];
for (var j = i; j < encoded.length && j < i + len; ++j) {
sub.push(encoded[j]);
}
const opts = resizable ? { maxByteLength: sub.length } : undefined;
var uintArray = new Uint8Array(createBuffer(arrayBufferOrSharedArrayBuffer, sub.length, opts));
uintArray.set(sub);
out += decoder.decode(uintArray, {stream: true});
}
var uintArray = new Uint8Array(createBuffer(arrayBufferOrSharedArrayBuffer, sub.length));
uintArray.set(sub);
out += decoder.decode(uintArray, {stream: true});
}
out += decoder.decode();
assert_equals(out, string);
}, 'Streaming decode: ' + encoding + ', ' + len + ' byte window (' + arrayBufferOrSharedArrayBuffer + ')');
}
});
out += decoder.decode();
assert_equals(out, string);
}, 'Streaming decode: ' + encoding + ', ' + len + ' byte window (' + (resizable ? "resizable " : "") + arrayBufferOrSharedArrayBuffer + ')');
}
});

test(() => {
function bytes(byteArray) {
const view = new Uint8Array(createBuffer(arrayBufferOrSharedArrayBuffer, byteArray.length));
view.set(byteArray);
return view;
}
test(() => {
function bytes(byteArray) {
const opts = resizable ? { maxByteLength: byteArray.length } : undefined;
const view = new Uint8Array(createBuffer(arrayBufferOrSharedArrayBuffer, byteArray.length, opts));
view.set(byteArray);
return view;
}

const decoder = new TextDecoder();
const decoder = new TextDecoder();

assert_equals(decoder.decode(bytes([0xC1]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(), "");
assert_equals(decoder.decode(bytes([0xC1]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(), "");

assert_equals(decoder.decode(bytes([0xF5]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(), "");
assert_equals(decoder.decode(bytes([0xF5]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(), "");

assert_equals(decoder.decode(bytes([0xE0, 0x41]), {stream: true}), "\uFFFDA");
assert_equals(decoder.decode(bytes([0x42])), "B");
assert_equals(decoder.decode(bytes([0xE0, 0x41]), {stream: true}), "\uFFFDA");
assert_equals(decoder.decode(bytes([0x42])), "B");

assert_equals(decoder.decode(bytes([0xE0, 0x80]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");
assert_equals(decoder.decode(bytes([0xE0, 0x80]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");

assert_equals(decoder.decode(bytes([0xED, 0xA0]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");
assert_equals(decoder.decode(bytes([0xED, 0xA0]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");

assert_equals(decoder.decode(bytes([0xF0, 0x41]), {stream: true}), "\uFFFDA");
assert_equals(decoder.decode(bytes([0x42]), {stream: true}), "B");
assert_equals(decoder.decode(bytes([0x43])), "C");
assert_equals(decoder.decode(bytes([0xF0, 0x41]), {stream: true}), "\uFFFDA");
assert_equals(decoder.decode(bytes([0x42]), {stream: true}), "B");
assert_equals(decoder.decode(bytes([0x43])), "C");

assert_equals(decoder.decode(bytes([0xF0, 0x80]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");
assert_equals(decoder.decode(bytes([0xF0, 0x80]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");

assert_equals(decoder.decode(bytes([0xF4, 0xA0]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");
assert_equals(decoder.decode(bytes([0xF4, 0xA0]), {stream: true}), "\uFFFD\uFFFD");
assert_equals(decoder.decode(bytes([0x80]), {stream: true}), "\uFFFD");
assert_equals(decoder.decode(bytes([0x80])), "\uFFFD");

assert_equals(decoder.decode(bytes([0xF0, 0x90, 0x41]), {stream: true}), "\uFFFDA");
assert_equals(decoder.decode(bytes([0x42])), "B");
assert_equals(decoder.decode(bytes([0xF0, 0x90, 0x41]), {stream: true}), "\uFFFDA");
assert_equals(decoder.decode(bytes([0x42])), "B");

// 4-byte UTF-8 sequences always correspond to non-BMP characters. Here
// we make sure that, although the first 3 bytes are enough to emit the
// lead surrogate, it only gets emitted when the fourth byte is read.
assert_equals(decoder.decode(bytes([0xF0, 0x9F, 0x92]), {stream: true}), "");
assert_equals(decoder.decode(bytes([0xA9])), "\u{1F4A9}");
}, `Streaming decode: UTF-8 chunk tests (${arrayBufferOrSharedArrayBuffer})`);
// 4-byte UTF-8 sequences always correspond to non-BMP characters. Here
// we make sure that, although the first 3 bytes are enough to emit the
// lead surrogate, it only gets emitted when the fourth byte is read.
assert_equals(decoder.decode(bytes([0xF0, 0x9F, 0x92]), {stream: true}), "");
assert_equals(decoder.decode(bytes([0xA9])), "\u{1F4A9}");
}, `Streaming decode: UTF-8 chunk tests (${resizable ? "resizable " : ""}${arrayBufferOrSharedArrayBuffer})`);
})
})
14 changes: 0 additions & 14 deletions webidl/ecmascript-binding/allow-resizable.html
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Expand Up @@ -14,18 +14,4 @@
new Response(new Uint8Array(rab));
});
}, "APIs without [AllowResizable] throw when passed resizable ArrayBuffers");

test(t => {
const enc = new TextEncoder();

// Fixed-length SABs should not throw
const sab = createBuffer('SharedArrayBuffer', 16);
enc.encodeInto("foobar", new Uint8Array(sab));

const gsab = createBuffer('SharedArrayBuffer', 16, { maxByteLength: 1024 });
// TextEncoder.encodeInto doesn't have [AllowResizable] but has [AllowShared]
assert_throws_js(TypeError, () => {
enc.encodeInto("foobar", new Uint8Array(gsab));
});
}, "APIs with [AllowShared] but without [AllowResizable] throw when passed growable SharedArrayBuffers");
Comment on lines -17 to -30
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@daxpedda daxpedda Mar 20, 2026

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No API exists that fulfills these conditions apart from FileSystemSyncAccessHandle.read/write().
I felt like handling this here would be out of scope.

</script>
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