hackpro-sdk
Version:
79 lines • 3.47 kB
JavaScript
"use strict";
/*
* Copyright 2019 balena.io
*
* Licensed 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.
*/
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
Object.defineProperty(exports, "__esModule", { value: true });
const readable_stream_1 = require("readable-stream");
const shared_1 = require("./shared");
class SparseReadStream extends readable_stream_1.Readable {
constructor(source, blocks, chunkSize, verify, generateChecksums, options = {}) {
super(Object.assign(Object.assign({}, options), { objectMode: true }));
this.source = source;
this.blocks = blocks;
this.chunkSize = chunkSize;
this.positionInBlock = 0;
this.stateIterator = shared_1.createSparseReaderStateIterator(blocks, verify, generateChecksums);
this.nextBlock();
}
_read() {
return __awaiter(this, void 0, void 0, function* () {
try {
this.push(yield this.__read());
}
catch (error) {
this.emit('error', error);
this.push(null);
}
});
}
nextBlock() {
this.state = this.stateIterator.next().value;
this.positionInBlock = 0;
}
__read() {
return __awaiter(this, void 0, void 0, function* () {
if (this.state === undefined) {
// No current block means we're done reading
return null;
}
const length = Math.min(this.chunkSize, this.state.subBlock.length - this.positionInBlock);
const buffer = Buffer.allocUnsafe(length);
yield this.source.read(buffer, 0, length, this.state.subBlock.offset + this.positionInBlock);
if (this.state.hasher !== undefined) {
this.state.hasher.update(buffer);
}
const chunk = {
buffer,
position: this.state.subBlock.offset + this.positionInBlock,
};
this.positionInBlock += length;
if (this.positionInBlock === this.state.subBlock.length) {
this.nextBlock();
}
return chunk;
});
}
}
exports.SparseReadStream = SparseReadStream;
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