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WIP Add some backpressure tests for compose

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This commit is contained in:
Jerry Kurian
2019-09-07 11:04:33 -04:00
parent d5f3fd8bd8
commit cd10649d44
7 changed files with 221 additions and 66 deletions
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34
src/functions/demux.ts
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@@ -14,6 +14,7 @@ export function demux(
}
class Demux extends Writable {
public isWritable: boolean;
private streamsByKey: {
[key: string]: {
stream: NodeJS.WritableStream | NodeJS.ReadWriteStream;
@@ -21,7 +22,6 @@ class Demux extends Writable {
};
};
private demuxer: (chunk: any) => string;
private isWritable: boolean;
private nonWritableStreams: Array<string>;
private construct: (
destKey?: string,
@@ -43,9 +43,10 @@ class Demux extends Writable {
this.construct = construct;
this.streamsByKey = {};
this.isWritable = true;
this.nonWritableStreams = [];
}
public _write(chunk: any, encoding: string, cb: any) {
public _write(chunk: any, encoding?: any, cb?: any) {
const destKey = this.demuxer(chunk);
if (this.streamsByKey[destKey] === undefined) {
this.streamsByKey[destKey] = {
@@ -57,35 +58,22 @@ class Demux extends Writable {
// Set writable to false
// keep state of all the streams, if one is not writable demux shouldnt be writable
// Small optimization is to keep writing until you get a following event to the unwritable destination
let res = false;
if (this.isWritable && this.streamsByKey[destKey].writable) {
if (this.streamsByKey[destKey].writable && this.isWritable) {
res = this.streamsByKey[destKey].stream.write(chunk, encoding, cb);
} else if (this.isWritable) {
this.isWritable = false;
// Buffer chunk?
return this.isWritable;
}
/* If write above returns false and the stream written to was writable previously, we need to make demux
* non-writable and update state to know the stream is nonWritable.
* If write returns true and the stream was previously not writable, we need to update which streams
* are non writable and determine if it is safe for demux to become writable (all streams are writable)
*/
if (!res) {
if (!res && this.isWritable) {
this.isWritable = false;
this.streamsByKey[destKey].writable = false;
this.nonWritableStreams.push(destKey);
this.isWritable = false;
this.streamsByKey[destKey].stream.once("drain", () => {
this.streamsByKey[destKey].writable = true;
this.nonWritableStreams = this.nonWritableStreams.filter(
key => key !== destKey,
);
this.nonWritableStreams.filter(key => key !== destKey);
this.isWritable = this.nonWritableStreams.length === 0;
this.streamsByKey[destKey].stream.write(chunk, encoding, cb);
if (this.isWritable) {
this.emit("drain");
}
});
}
return this.writable;
}
}