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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
import { TypeMap } from '../../type.js';
import { RecordBatch } from '../../recordbatch.js';
import { AsyncByteQueue } from '../../io/stream.js';
import { RecordBatchReader } from '../../ipc/reader.js';
/** @ignore */
export function recordBatchReaderThroughDOMStream<T extends TypeMap = any>(writableStrategy?: ByteLengthQueuingStrategy, readableStrategy?: { autoDestroy: boolean }) {
const queue = new AsyncByteQueue();
let reader: RecordBatchReader<T> | null = null;
const readable = new ReadableStream<RecordBatch<T>>({
async cancel() { await queue.close(); },
async start(controller) { await next(controller, reader || (reader = await open())); },
async pull(controller) { reader ? await next(controller, reader) : controller.close(); }
});
return { writable: new WritableStream(queue, { 'highWaterMark': 2 ** 14, ...writableStrategy }), readable };
async function open() {
return await (await RecordBatchReader.from<T>(queue)).open(readableStrategy);
}
async function next(controller: ReadableStreamDefaultController<RecordBatch<T>>, reader: RecordBatchReader<T>) {
let size = controller.desiredSize;
let r: IteratorResult<RecordBatch<T>> | null = null;
while (!(r = await reader.next()).done) {
controller.enqueue(r.value);
if (size != null && --size <= 0) {
return;
}
}
controller.close();
}
}
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