multi-readable
Version:
Serial connecting readable streams, strictly following the back pressure and highWaterMark
176 lines (175 loc) • 7.44 kB
JavaScript
;
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());
});
};
var __asyncValues = (this && this.__asyncValues) || function (o) {
if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
var m = o[Symbol.asyncIterator], i;
return m ? m.call(o) : (o = typeof __values === "function" ? __values(o) : o[Symbol.iterator](), i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i);
function verb(n) { i[n] = o[n] && function (v) { return new Promise(function (resolve, reject) { v = o[n](v), settle(resolve, reject, v.done, v.value); }); }; }
function settle(resolve, reject, d, v) { Promise.resolve(v).then(function(v) { resolve({ value: v, done: d }); }, reject); }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.MultiObjectReadable = exports.MultiBufferReadable = void 0;
const stream_1 = require("stream");
class BaseMultiReadable extends stream_1.Readable {
constructor(streams, opts) {
super(opts);
const readableObjectMode = !!(opts === null || opts === void 0 ? void 0 : opts.objectMode);
const isReadable = stream_1.Readable.isReadable
? stream_1.Readable.isReadable
: (stream) => stream instanceof stream_1.Readable;
if (Array.isArray(streams) &&
streams.every((stream) => {
if (!isReadable(stream)) {
return false;
}
if (stream.readableObjectMode !== readableObjectMode) {
return false;
}
return true;
})) {
this.__streams = streams;
this.__start().catch((reason) => {
this.destroy(reason);
});
}
else {
throw new Error("arguments type error");
}
}
_read(size) {
var _a;
(_a = this.__read) === null || _a === void 0 ? void 0 : _a.call(this, size);
}
_destroy(error, callback) {
var _a;
for (const stream of this.__streams) {
if (!stream.destroyed) {
stream.destroy();
}
}
(_a = this.__read) === null || _a === void 0 ? void 0 : _a.call(this, -1);
callback(error);
}
__get_size() {
return __awaiter(this, void 0, void 0, function* () {
try {
return yield new Promise((resolve) => {
this.__read = resolve;
});
}
finally {
this.__read = null;
}
});
}
}
class MultiBufferReadable extends BaseMultiReadable {
constructor(streams, opts) {
super(streams, Object.assign(Object.assign({}, opts), { objectMode: false }));
}
__start() {
var e_1, _a;
return __awaiter(this, void 0, void 0, function* () {
let size = 0;
let size_promise = this.__get_size();
let cache;
const clear = () => {
size = 0;
size_promise = this.__get_size();
cache = null;
};
for (const stream of this.__streams) {
try {
for (var stream_2 = (e_1 = void 0, __asyncValues(stream)), stream_2_1; stream_2_1 = yield stream_2.next(), !stream_2_1.done;) {
const chunk = stream_2_1.value;
if (!Buffer.isBuffer(chunk)) {
throw new Error("chunk is not a buffer");
}
if (size === 0) {
size = yield size_promise;
}
cache = cache ? Buffer.concat([cache, chunk]) : chunk;
let cache_len = cache.length;
if (cache_len > size) {
do {
this.push(cache.slice(0, size));
cache = cache.slice(size);
cache_len = cache.length;
size = yield this.__get_size();
if (cache_len < size) {
break;
}
else if (cache_len === size) {
this.push(cache);
clear();
break;
}
} while (true);
}
else if (cache_len === size) {
this.push(cache);
clear();
}
}
}
catch (e_1_1) { e_1 = { error: e_1_1 }; }
finally {
try {
if (stream_2_1 && !stream_2_1.done && (_a = stream_2.return)) yield _a.call(stream_2);
}
finally { if (e_1) throw e_1.error; }
}
}
if (cache) {
this.push(cache);
cache = null;
}
this.push(null);
});
}
}
exports.MultiBufferReadable = MultiBufferReadable;
class MultiObjectReadable extends BaseMultiReadable {
constructor(streams, opts) {
super(streams, Object.assign(Object.assign({}, opts), { objectMode: true }));
}
__start() {
var e_2, _a;
return __awaiter(this, void 0, void 0, function* () {
let size = 0;
let size_promise = this.__get_size();
for (const stream of this.__streams) {
try {
for (var stream_3 = (e_2 = void 0, __asyncValues(stream)), stream_3_1; stream_3_1 = yield stream_3.next(), !stream_3_1.done;) {
const object = stream_3_1.value;
if (size === 0) {
size = yield size_promise;
}
const r = this.push(object);
if (!r) {
size = 0;
size_promise = this.__get_size();
}
}
}
catch (e_2_1) { e_2 = { error: e_2_1 }; }
finally {
try {
if (stream_3_1 && !stream_3_1.done && (_a = stream_3.return)) yield _a.call(stream_3);
}
finally { if (e_2) throw e_2.error; }
}
}
this.push(null);
});
}
}
exports.MultiObjectReadable = MultiObjectReadable;