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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
function AsyncIteratorIdentity() {
return this;
}
function AsyncGeneratorNext(val) {
assert(IsAsyncGeneratorObject(this),
"ThisArgument must be a generator object for async generators");
return resumeGenerator(this, val, "next");
}
function AsyncGeneratorThrow(val) {
assert(IsAsyncGeneratorObject(this),
"ThisArgument must be a generator object for async generators");
return resumeGenerator(this, val, "throw");
}
function AsyncGeneratorReturn(val) {
assert(IsAsyncGeneratorObject(this),
"ThisArgument must be a generator object for async generators");
return resumeGenerator(this, val, "return");
}
/* ECMA262 7.4.7 AsyncIteratorClose */
async function AsyncIteratorClose(iteratorRecord, value) {
// Step 3.
const iterator = iteratorRecord.iterator;
// Step 4.
const returnMethod = iterator.return;
// Step 5.
if (returnMethod !== undefined && returnMethod !== null) {
const result = await callContentFunction(returnMethod, iterator);
// Step 8.
if (!IsObject(result)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, result));
}
}
// Step 5b & 9.
return value;
}
/* Iterator Helpers proposal 1.1.1 */
function GetAsyncIteratorDirectWrapper(obj) {
// Step 1.
if (!IsObject(obj)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, obj);
}
// Step 2.
const nextMethod = obj.next;
// Step 3.
if (!IsCallable(nextMethod)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, nextMethod);
}
// Steps 4-5.
return {
// Use a named function expression instead of a method definition, so
// we don't create an inferred name for this function at runtime.
[std_asyncIterator]: function AsyncIteratorMethod() {
return this;
},
next(value) {
return callContentFunction(nextMethod, obj, value);
},
async return(value) {
const returnMethod = obj.return;
if (returnMethod !== undefined && returnMethod !== null) {
return callContentFunction(returnMethod, obj, value);
}
return {done: true, value};
},
};
}
/* AsyncIteratorHelper object prototype methods. */
function AsyncIteratorHelperNext(value) {
let O;
if (!IsObject(this) || (O = GuardToAsyncIteratorHelper(this)) === null) {
return callFunction(CallAsyncIteratorHelperMethodIfWrapped, this,
value, "AsyncIteratorHelperNext");
}
const generator = UnsafeGetReservedSlot(O, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT);
return callFunction(IntrinsicAsyncGeneratorNext, generator, value);
}
function AsyncIteratorHelperReturn(value) {
let O;
if (!IsObject(this) || (O = GuardToAsyncIteratorHelper(this)) === null) {
return callFunction(CallAsyncIteratorHelperMethodIfWrapped, this,
value, "AsyncIteratorHelperReturn");
}
const generator = UnsafeGetReservedSlot(O, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT);
return callFunction(IntrinsicAsyncGeneratorReturn, generator, value);
}
function AsyncIteratorHelperThrow(value) {
let O;
if (!IsObject(this) || (O = GuardToAsyncIteratorHelper(this)) === null) {
return callFunction(CallAsyncIteratorHelperMethodIfWrapped, this,
value, "AsyncIteratorHelperThrow");
}
const generator = UnsafeGetReservedSlot(O, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT);
return callFunction(IntrinsicAsyncGeneratorThrow, generator, value);
}
// AsyncIterator lazy Iterator Helper methods
// Iterator Helpers proposal 2.1.6.2-2.1.6.7
//
// The AsyncIterator lazy methods are structured closely to how the Iterator
// lazy methods are. See builtin/Iterator.js for the reasoning.
/* Iterator Helpers proposal 2.1.6.2 Prelude */
function AsyncIteratorMap(mapper) {
// Step 1.
const iterated = GetIteratorDirect(this);
// Step 2.
if (!IsCallable(mapper)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, mapper));
}
const iteratorHelper = NewAsyncIteratorHelper();
const generator = AsyncIteratorMapGenerator(iterated, mapper);
callFunction(IntrinsicAsyncGeneratorNext, generator);
UnsafeSetReservedSlot(iteratorHelper, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT, generator);
return iteratorHelper;
}
/* Iterator Helpers proposal 2.1.6.2 Body */
async function* AsyncIteratorMapGenerator(iterated, mapper) {
// Step 1.
let lastValue;
// Step 2.
let needClose = true;
try {
yield;
needClose = false;
for (let next = await IteratorNext(iterated, lastValue);
!next.done;
next = await IteratorNext(iterated, lastValue)) {
// Step c.
const value = next.value;
// Steps d-i.
needClose = true;
lastValue = yield callContentFunction(mapper, undefined, value);
needClose = false;
}
} finally {
if (needClose) {
AsyncIteratorClose(iterated);
}
}
}
/* Iterator Helpers proposal 2.1.6.3 Prelude */
function AsyncIteratorFilter(filterer) {
// Step 1.
const iterated = GetIteratorDirect(this);
// Step 2.
if (!IsCallable(filterer)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, filterer));
}
const iteratorHelper = NewAsyncIteratorHelper();
const generator = AsyncIteratorFilterGenerator(iterated, filterer);
callFunction(IntrinsicAsyncGeneratorNext, generator);
UnsafeSetReservedSlot(iteratorHelper, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT, generator);
return iteratorHelper;
}
/* Iterator Helpers proposal 2.1.6.3 Body */
async function* AsyncIteratorFilterGenerator(iterated, filterer) {
// Step 1.
let lastValue;
// Step 2.
let needClose = true;
try {
yield;
needClose = false;
for (let next = await IteratorNext(iterated, lastValue);
!next.done;
next = await IteratorNext(iterated, lastValue)) {
// Step c.
const value = next.value;
// Steps d-h.
needClose = true;
if (await callContentFunction(filterer, undefined, value)) {
lastValue = yield value;
}
needClose = false;
}
} finally {
if (needClose) {
AsyncIteratorClose(iterated);
}
}
}
/* Iterator Helpers proposal 2.1.6.4 Prelude */
function AsyncIteratorTake(limit) {
// Step 1.
const iterated = GetIteratorDirect(this);
// Step 2.
const remaining = ToInteger(limit);
// Step 3.
if (remaining < 0) {
ThrowRangeError(JSMSG_NEGATIVE_LIMIT);
}
const iteratorHelper = NewAsyncIteratorHelper();
const generator = AsyncIteratorTakeGenerator(iterated, remaining);
callFunction(IntrinsicAsyncGeneratorNext, generator);
UnsafeSetReservedSlot(iteratorHelper, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT, generator);
return iteratorHelper;
}
/* Iterator Helpers proposal 2.1.6.4 Body */
async function* AsyncIteratorTakeGenerator(iterated, remaining) {
// Step 1.
let lastValue;
// Step 2.
let needClose = true;
try {
yield;
needClose = false;
for (; remaining > 0; remaining--) {
const next = await IteratorNext(iterated, lastValue);
if (next.done) {
return undefined;
}
const value = next.value;
needClose = true;
lastValue = yield value;
needClose = false;
}
} finally {
if (needClose) {
AsyncIteratorClose(iterated, undefined);
}
}
return AsyncIteratorClose(iterated, undefined);
}
/* Iterator Helpers proposal 2.1.6.5 Prelude */
function AsyncIteratorDrop(limit) {
// Step 1.
const iterated = GetIteratorDirect(this);
// Step 2.
const remaining = ToInteger(limit);
// Step 3.
if (remaining < 0) {
ThrowRangeError(JSMSG_NEGATIVE_LIMIT);
}
const iteratorHelper = NewAsyncIteratorHelper();
const generator = AsyncIteratorDropGenerator(iterated, remaining);
callFunction(IntrinsicAsyncGeneratorNext, generator);
UnsafeSetReservedSlot(iteratorHelper, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT, generator);
return iteratorHelper;
}
/* Iterator Helpers proposal 2.1.6.5 Body */
async function* AsyncIteratorDropGenerator(iterated, remaining) {
let needClose = true;
try {
yield;
needClose = false;
// Step 1.
for (; remaining > 0; remaining--) {
const next = await IteratorNext(iterated);
if (next.done) {
return;
}
}
// Step 2.
let lastValue;
// Step 3.
for (let next = await IteratorNext(iterated, lastValue);
!next.done;
next = await IteratorNext(iterated, lastValue)) {
// Steps c-d.
const value = next.value;
needClose = true;
lastValue = yield value;
needClose = false;
}
} finally {
if (needClose) {
AsyncIteratorClose(iterated);
}
}
}
/* Iterator Helpers proposal 2.1.6.6 Prelude */
function AsyncIteratorAsIndexedPairs() {
// Step 1.
const iterated = GetIteratorDirect(this);
const iteratorHelper = NewAsyncIteratorHelper();
const generator = AsyncIteratorAsIndexedPairsGenerator(iterated);
callFunction(IntrinsicAsyncGeneratorNext, generator);
UnsafeSetReservedSlot(iteratorHelper, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT, generator);
return iteratorHelper;
}
/* Iterator Helpers proposal 2.1.6.6 Body */
async function* AsyncIteratorAsIndexedPairsGenerator(iterated) {
let needClose = true;
try {
yield;
needClose = false;
// Step 2.
let lastValue;
// Step 3.
for (let next = await IteratorNext(iterated, lastValue), index = 0;
!next.done;
next = await IteratorNext(iterated, lastValue), index++) {
// Steps c-g.
const value = next.value;
needClose = true;
lastValue = yield [index, value];
needClose = false;
}
} finally {
if (needClose) {
AsyncIteratorClose(iterated);
}
}
}
/* Iterator Helpers proposal 2.1.6.7 Prelude */
function AsyncIteratorFlatMap(mapper) {
// Step 1.
const iterated = GetIteratorDirect(this);
// Step 2.
if (!IsCallable(mapper)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, mapper));
}
const iteratorHelper = NewAsyncIteratorHelper();
const generator = AsyncIteratorFlatMapGenerator(iterated, mapper);
callFunction(IntrinsicAsyncGeneratorNext, generator);
UnsafeSetReservedSlot(iteratorHelper, ASYNC_ITERATOR_HELPER_GENERATOR_SLOT, generator);
return iteratorHelper;
}
/* Iterator Helpers proposal 2.1.6.7 Body */
async function* AsyncIteratorFlatMapGenerator(iterated, mapper) {
let needClose = true;
try {
yield;
needClose = false;
// Step 1.
for (let next = await IteratorNext(iterated);
!next.done;
next = await IteratorNext(iterated)) {
// Step c.
const value = next.value;
needClose = true;
// Step d.
const mapped = await callContentFunction(mapper, undefined, value);
// Steps f-k.
for await (const innerValue of allowContentIter(mapped)) {
yield innerValue;
}
needClose = false;
}
} finally {
if (needClose) {
AsyncIteratorClose(iterated);
}
}
}
/* Iterator Helpers proposal 2.1.6.8 */
async function AsyncIteratorReduce(reducer/*, initialValue*/) {
// Step 1.
const iterated = GetAsyncIteratorDirectWrapper(this);
// Step 2.
if (!IsCallable(reducer)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, reducer));
}
// Step 3.
let accumulator;
if (arguments.length === 1) {
// Step a.
const next = await callContentFunction(iterated.next, iterated);
if (!IsObject(next)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, next));
}
// Step b.
if (next.done) {
ThrowTypeError(JSMSG_EMPTY_ITERATOR_REDUCE);
}
// Step c.
accumulator = next.value;
} else {
// Step 4.
accumulator = arguments[1];
}
// Step 5.
for await (const value of allowContentIter(iterated)) {
// Steps d-h.
accumulator = await callContentFunction(reducer, undefined, accumulator, value);
}
// Step 5b.
return accumulator;
}
/* Iterator Helpers proposal 2.1.6.9 */
async function AsyncIteratorToArray() {
// Step 1.
const iterated = {[std_asyncIterator]: () => this};
// Step 2.
const items = [];
let index = 0;
// Step 3.
for await (const value of allowContentIter(iterated)) {
// Step d.
_DefineDataProperty(items, index++, value);
}
// Step 3b.
return items;
}
/* Iterator Helpers proposal 2.1.6.10 */
async function AsyncIteratorForEach(fn) {
// Step 1.
const iterated = GetAsyncIteratorDirectWrapper(this);
// Step 2.
if (!IsCallable(fn)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
}
// Step 3.
for await (const value of allowContentIter(iterated)) {
// Steps d-g.
await callContentFunction(fn, undefined, value);
}
}
/* Iterator Helpers proposal 2.1.6.11 */
async function AsyncIteratorSome(fn) {
// Step 1.
const iterated = GetAsyncIteratorDirectWrapper(this);
// Step 2.
if (!IsCallable(fn)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
}
// Step 3.
for await (const value of allowContentIter(iterated)) {
// Steps d-h.
if (await callContentFunction(fn, undefined, value)) {
return true;
}
}
// Step 3b.
return false;
}
/* Iterator Helpers proposal 2.1.6.12 */
async function AsyncIteratorEvery(fn) {
// Step 1.
const iterated = GetAsyncIteratorDirectWrapper(this);
// Step 2.
if (!IsCallable(fn)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
}
// Step 3.
for await (const value of allowContentIter(iterated)) {
// Steps d-h.
if (!await callContentFunction(fn, undefined, value)) {
return false;
}
}
// Step 3b.
return true;
}
/* Iterator Helpers proposal 2.1.6.13 */
async function AsyncIteratorFind(fn) {
// Step 1.
const iterated = GetAsyncIteratorDirectWrapper(this);
// Step 2.
if (!IsCallable(fn)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
}
// Step 3.
for await (const value of allowContentIter(iterated)) {
// Steps d-h.
if (await callContentFunction(fn, undefined, value)) {
return value;
}
}
}
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