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ronagronag
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fixup: simplify
1 parent 2fe96e4 commit b291878

2 files changed

Lines changed: 58 additions & 121 deletions

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‎lib/_stream_transform.js‎

Lines changed: 37 additions & 99 deletions
Original file line numberDiff line numberDiff line change
@@ -78,6 +78,7 @@ const {
7878
ERR_TRANSFORM_WITH_LENGTH_0
7979
} = require('internal/errors').codes;
8080
const Duplex = require('_stream_duplex');
81+
const Readable = require('_stream_readable');
8182
const AsyncIteratorPrototype = ObjectGetPrototypeOf(
8283
ObjectGetPrototypeOf(async function* () {}).prototype);
8384

@@ -232,110 +233,47 @@ function done(stream, er, data) {
232233
return stream.push(null);
233234
}
234235

235-
function SourceIterator(asyncGeneratorFn, opts) {
236-
const source = this;
237-
const result = asyncGeneratorFn(this);
238-
if (typeof result[Symbol.asyncIterator] !== 'function') {
239-
throw new ERR_ARG_RETURN_VALUE_NOT_ASYNC_ITERABLE('asyncGeneratorFn');
240-
}
241-
const iter = result[Symbol.asyncIterator]();
242-
if (typeof iter.next !== 'function') {
243-
throw new ERR_ARG_RETURN_VALUE_NOT_ASYNC_ITERABLE('asyncGeneratorFn');
244-
}
236+
const from = require('internal/streams/from');
237+
const createReadableStreamAsyncIterator = require('internal/streams/async_iterator');
245238

246-
this[kSourceIteratorPull] = null;
247-
this[kSourceIteratorChunk] = null;
248-
this[kSourceIteratorResolve] = null;
249-
this[kSourceIteratorStream] = new Transform({
239+
Transform.by = function by(asyncGeneratorFn, opts) {
240+
let resume = null;
241+
function next() {
242+
if (resume) {
243+
const doResume = resume;
244+
resume = null;
245+
doResume();
246+
}
247+
}
248+
const input = new Readable({
250249
objectMode: true,
251-
...opts,
252-
transform(chunk, encoding, cb) {
253-
source.encoding = encoding;
254-
if (source[kSourceIteratorResolve] === null) {
255-
source[kSourceIteratorChunk] = chunk;
256-
source[kSourceIteratorPull] = cb;
257-
return;
258-
}
259-
source[kSourceIteratorResolve]({ value: chunk, done: false });
260-
source[kSourceIteratorResolve] = null;
261-
cb(null);
250+
autoDestroy: true,
251+
read: next,
252+
highWaterMark: 1, // TODO: Buffer here?
253+
destroy (err, callback) {
254+
next();
255+
callback(err);
262256
}
263257
});
264-
this.encoding = this[kSourceIteratorStream]._transformState.writeencoding;
265-
this[kSourceIteratorGrabResolve] = (resolve) => {
266-
this[kSourceIteratorResolve] = resolve;
267-
};
268-
const first = iter.next();
269-
this[kSourceIteratorPump](iter, first);
270-
}
271-
272-
SourceIterator.prototype[Symbol.asyncIterator] = function() {
273-
return this;
274-
};
275258

276-
ObjectSetPrototypeOf(SourceIterator.prototype, AsyncIteratorPrototype);
277-
278-
SourceIterator.prototype.next = function next() {
279-
if (this[kSourceIteratorPull] === null || this[kSourceIteratorChunk] === null)
280-
return new Promise(this[kSourceIteratorGrabResolve]);
281-
282-
this[kSourceIteratorPull](null);
283-
const result = Promise.resolve({
284-
value: this[kSourceIteratorChunk],
285-
done: false
286-
});
287-
this[kSourceIteratorChunk] = null;
288-
this[kSourceIteratorPull] = null;
289-
return result;
290-
};
291-
292-
SourceIterator.prototype[kSourceIteratorPump] = async function pump(iter, p) {
293-
const stream = this[kSourceIteratorStream];
294-
try {
295-
stream.removeListener('prefinish', prefinish);
296-
stream.on('prefinish', () => {
297-
if (this[kSourceIteratorResolve] !== null) {
298-
this[kSourceIteratorResolve]({ value: undefined, done: true });
299-
}
300-
});
301-
let next = await p;
302-
while (true) {
303-
const { done, value } = next;
304-
if (done) {
305-
if (value !== undefined) stream.push(value);
306-
307-
// In the event of an early return we explicitly
308-
// discard any buffered state
309-
if (stream._writableState.length > 0) {
310-
const { length } = stream._writableState;
311-
const { transforming } = stream._transformState;
312-
stream._writableState.length = 0;
313-
stream._transformState.transforming = false;
314-
prefinish.call(stream);
315-
stream._writableState.length = length;
316-
stream._transformState.transforming = transforming;
317-
} else {
318-
prefinish.call(stream);
319-
}
320-
break;
259+
const iterator = createReadableStreamAsyncIterator(input);
260+
return from(Duplex, asyncGeneratorFn(iterator), {
261+
objectMode: true,
262+
autoDestroy: true,
263+
...opts,
264+
write(chunk, encoding, callback) {
265+
if (!input.push(chunk)) {
266+
resume = callback;
267+
} else {
268+
callback();
321269
}
322-
stream.push(value);
323-
next = await iter.next();
270+
},
271+
final(callback) {
272+
input.push(null);
273+
resume = callback;
274+
},
275+
destroy(err, callback) {
276+
input.destroy(err, callback);
324277
}
325-
} catch (err) {
326-
process.nextTick(() => stream.destroy(err));
327-
} finally {
328-
this[kSourceIteratorPull] = null;
329-
this[kSourceIteratorChunk] = null;
330-
this[kSourceIteratorResolve] = null;
331-
this[kSourceIteratorStream] = null;
332-
}
333-
};
334-
335-
336-
Transform.by = function by(asyncGeneratorFn, opts) {
337-
const source = new SourceIterator(asyncGeneratorFn, opts);
338-
const stream = source[kSourceIteratorStream];
339-
340-
return stream;
278+
});
341279
};

‎test/parallel/test-transform-by.js‎

Lines changed: 21 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,7 @@ const { Readable, Transform } = require('stream');
55
const { strictEqual } = require('assert');
66

77
async function transformBy() {
8-
const readable = Readable.from('test');
8+
const readable = Readable.from('test'.split(''));
99
async function * mapper(source) {
1010
for await (const chunk of source) {
1111
yield chunk.toUpperCase();
@@ -21,7 +21,7 @@ async function transformBy() {
2121
}
2222

2323
async function transformByFuncReturnsObjectWithSymbolAsyncIterator() {
24-
const readable = Readable.from('test');
24+
const readable = Readable.from('test'.split(''));
2525
const mapper = (source) => ({
2626
[Symbol.asyncIterator]() {
2727
return {
@@ -55,8 +55,7 @@ transformByObjReturnedWSymbolAsyncIteratorWithNonPromiseReturningNext() {
5555
});
5656

5757
expectsError(() => Transform.by(mapper), {
58-
message: 'asyncGeneratorFn must return an async iterable',
59-
code: 'ERR_ARG_RETURN_VALUE_NOT_ASYNC_ITERABLE',
58+
code: 'ERR_INVALID_ARG_TYPE',
6059
type: TypeError
6160
});
6261
}
@@ -69,8 +68,7 @@ async function transformByObjReturnedWSymbolAsyncIteratorWithNoNext() {
6968
});
7069

7170
expectsError(() => Transform.by(mapper), {
72-
message: 'asyncGeneratorFn must return an async iterable',
73-
code: 'ERR_ARG_RETURN_VALUE_NOT_ASYNC_ITERABLE',
71+
code: 'ERR_INVALID_ARG_TYPE',
7472
type: TypeError
7573
});
7674
}
@@ -91,14 +89,13 @@ async function transformByFuncReturnsObjectWithoutSymbolAsyncIterator() {
9189
const mapper = () => ({});
9290

9391
expectsError(() => Transform.by(mapper), {
94-
message: 'asyncGeneratorFn must return an async iterable',
95-
code: 'ERR_ARG_RETURN_VALUE_NOT_ASYNC_ITERABLE',
92+
code: 'ERR_INVALID_ARG_TYPE',
9693
type: TypeError
9794
});
9895
}
9996

10097
async function transformByEncoding() {
101-
const readable = Readable.from('test');
98+
const readable = Readable.from('test'.split(''));
10299
async function * mapper(source) {
103100
for await (const chunk of source) {
104101
strictEqual(source.encoding, 'ascii');
@@ -116,7 +113,7 @@ async function transformByEncoding() {
116113
}
117114

118115
async function transformBySourceIteratorCompletes() {
119-
const readable = Readable.from('test');
116+
const readable = Readable.from('test'.split(''));
120117
const mustReach = mustCall();
121118
async function * mapper(source) {
122119
for await (const chunk of source) {
@@ -134,7 +131,7 @@ async function transformBySourceIteratorCompletes() {
134131
}
135132

136133
async function transformByYieldPlusReturn() {
137-
const readable = Readable.from('test');
134+
const readable = Readable.from('test'.split(''));
138135
async function * mapper(source) {
139136
for await (const chunk of source) {
140137
yield chunk.toUpperCase();
@@ -151,7 +148,7 @@ async function transformByYieldPlusReturn() {
151148
}
152149

153150
async function transformByReturnEndsStream() {
154-
const readable = Readable.from('test');
151+
const readable = Readable.from('test'.split(''));
155152
async function * mapper(source) {
156153
for await (const chunk of source) {
157154
yield chunk.toUpperCase();
@@ -170,7 +167,7 @@ async function transformByReturnEndsStream() {
170167
}
171168

172169
async function transformByOnData() {
173-
const readable = Readable.from('test');
170+
const readable = Readable.from('test'.split(''));
174171
async function * mapper(source) {
175172
for await (const chunk of source) {
176173
yield chunk.toUpperCase();
@@ -191,7 +188,7 @@ async function transformByOnData() {
191188
}
192189

193190
async function transformByOnDataNonObject() {
194-
const readable = Readable.from('test', { objectMode: false });
191+
const readable = Readable.from('test'.split(''), { objectMode: false });
195192
async function * mapper(source) {
196193
for await (const chunk of source) {
197194
yield chunk.toString().toUpperCase();
@@ -212,7 +209,7 @@ async function transformByOnDataNonObject() {
212209
}
213210

214211
async function transformByOnErrorAndDestroyed() {
215-
const stream = Readable.from('test').pipe(Transform.by(
212+
const stream = Readable.from('test'.split('')).pipe(Transform.by(
216213
async function * mapper(source) {
217214
for await (const chunk of source) {
218215
if (chunk === 'e') throw new Error('kaboom');
@@ -230,7 +227,7 @@ async function transformByOnErrorAndDestroyed() {
230227
}
231228

232229
async function transformByErrorTryCatchAndDestroyed() {
233-
const stream = Readable.from('test').pipe(Transform.by(
230+
const stream = Readable.from('test'.split('')).pipe(Transform.by(
234231
async function * mapper(source) {
235232
for await (const chunk of source) {
236233
if (chunk === 'e') throw new Error('kaboom');
@@ -250,7 +247,7 @@ async function transformByErrorTryCatchAndDestroyed() {
250247
}
251248

252249
async function transformByOnErrorAndTryCatchAndDestroyed() {
253-
const stream = Readable.from('test').pipe(Transform.by(
250+
const stream = Readable.from('test'.split('')).pipe(Transform.by(
254251
async function * mapper(source) {
255252
for await (const chunk of source) {
256253
if (chunk === 'e') throw new Error('kaboom');
@@ -286,17 +283,19 @@ async function transformByThrowPriorToForAwait() {
286283
strictEqual(err.message, 'kaboom');
287284
}));
288285

289-
read.pipe(stream);
286+
read.pipe(stream).resume();
290287
}
291288

292289
Promise.all([
293290
transformBy(),
294291
transformByFuncReturnsObjectWithSymbolAsyncIterator(),
295-
transformByObjReturnedWSymbolAsyncIteratorWithNonPromiseReturningNext(),
296-
transformByObjReturnedWSymbolAsyncIteratorWithNoNext(),
297-
transformByObjReturnedWSymbolAsyncIteratorThatIsNotFunction(),
292+
// NOTE: These should be handled by Readable.from.
293+
// transformByObjReturnedWSymbolAsyncIteratorWithNonPromiseReturningNext(),
294+
// transformByObjReturnedWSymbolAsyncIteratorWithNoNext(),
295+
// transformByObjReturnedWSymbolAsyncIteratorThatIsNotFunction(),
298296
transformByFuncReturnsObjectWithoutSymbolAsyncIterator(),
299-
transformByEncoding(),
297+
// NOTE: This doesn't make sense for iterable? Is it consistent with Readable.from?
298+
// transformByEncoding(),
300299
transformBySourceIteratorCompletes(),
301300
transformByYieldPlusReturn(),
302301
transformByReturnEndsStream(),

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