@reactivex/ix-esnext-esm/asynciterable/todomstream.js

import { fromDOMStream } from './fromdomstream';
/** @ignore */
function memcpy(target, source, targetByteOffset = 0, sourceByteLength = source.byteLength) {
    const targetByteLength = target.byteLength;
    const dst = new Uint8Array(target.buffer, target.byteOffset, targetByteLength);
    const src = new Uint8Array(source.buffer, source.byteOffset, Math.min(sourceByteLength, targetByteLength));
    dst.set(src, targetByteOffset);
    return src.byteLength;
}
class AbstractUnderlyingSource {
    constructor(_source) {
        this._source = _source;
    }
    async cancel() {
        const source = this._source;
        if (source && source.return) {
            await source.return();
        }
        this._source = null;
    }
}
class UnderlyingAsyncIterableDefaultSource extends AbstractUnderlyingSource {
    constructor(source) {
        super(source);
    }
    async pull(controller) {
        const source = this._source;
        if (source) {
            const r = await source.next(controller.desiredSize);
            if (!r.done) {
                return controller.enqueue(r.value);
            }
        }
        controller.close();
    }
}
class UnderlyingAsyncIterableByteSource extends AbstractUnderlyingSource {
    constructor(reader, opts = {}) {
        super(reader);
        this.type = 'bytes';
        this.autoAllocateChunkSize = opts.autoAllocateChunkSize;
        this.fallbackDefaultSource = new UnderlyingAsyncIterableDefaultSource(reader);
    }
    async pull(controller) {
        if (!controller.byobRequest) {
            return await this.fallbackDefaultSource.pull(controller);
        }
        if (this._source) {
            const { view } = controller.byobRequest;
            const { done, value } = await this._source.next(view);
            if (!done) {
                // Did the source write into the BYOB view itself,
                // then yield us the `bytesWritten` value? If so,
                // pass that along
                if (typeof value === 'number') {
                    return controller.byobRequest.respond(value);
                }
                // otherwise if the source is only producing buffers
                // but doesn't expect to be given one, we should copy
                // the produced buffer into the front of the BYOB view
                if (ArrayBuffer.isView(value)) {
                    return value.buffer === view.buffer
                        ? controller.byobRequest.respondWithNewView(value)
                        : controller.byobRequest.respond(memcpy(view, value));
                }
            }
        }
        controller.close();
    }
}
// Generate subclasses of ReadableStream that conform to the
// AsyncIterable protocol. These classes are dynamically created
// the first time a ReadableStream is produced because ReadableStream
// is a browser-only API, and closure-compiler won't compile if they're
// statically defined at the module scope.
/** @ignore */
const asyncIterableReadableStream = (() => {
    let AsyncIterableReadableByteStream_;
    let AsyncIterableDefaultReadableStream_;
    // A function that's called the first time someone creates a
    // ReadableStream via `toDOMStream()`
    let createFirstTime = (source, opts) => {
        // Generate the subclasses with [Symbol.asyncIterator]() methods
        class AsyncIterableDefaultReadableStream extends ReadableStream {
            [Symbol.asyncIterator]() {
                return fromDOMStream(this)[Symbol.asyncIterator]();
            }
        }
        class AsyncIterableReadableByteStream extends ReadableStream {
            [Symbol.asyncIterator]() {
                return fromDOMStream(this, { mode: 'byob' })[Symbol.asyncIterator]();
            }
        }
        AsyncIterableReadableByteStream_ = AsyncIterableReadableByteStream;
        AsyncIterableDefaultReadableStream_ = AsyncIterableDefaultReadableStream;
        // Now point `createAsyncIterableReadableStream` to the function that
        // instantiates the classes we just created
        //tslint:disable-next-line
        createAsyncIterableReadableStream = createAsyncIterableReadableStreamEveryOtherTime;
        // Create and return the first ReadableStream<T> instance
        //tslint:disable-next-line
        return createAsyncIterableReadableStreamEveryOtherTime(source, opts);
    };
    // Shared function pointer that's called by the wrapper closure we return
    //tslint:disable-next-line
    let createAsyncIterableReadableStream = createFirstTime;
    // Create instances of the classes generated by `createFirstTime`
    let createAsyncIterableReadableStreamEveryOtherTime = (source, opts) => {
        return source instanceof UnderlyingAsyncIterableByteSource
            ? new AsyncIterableReadableByteStream_(source, opts)
            : new AsyncIterableDefaultReadableStream_(source, opts);
    };
    return (source, opts) => createAsyncIterableReadableStream(source, opts);
})();
export function toDOMStream(source, options) {
    if (!options || options.type !== 'bytes') {
        return asyncIterableReadableStream(new UnderlyingAsyncIterableDefaultSource(source[Symbol.asyncIterator]()), options);
    }
    return asyncIterableReadableStream(new UnderlyingAsyncIterableByteSource(source[Symbol.asyncIterator]()), options);
}

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