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fix: use stream helpers #1

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fix: use stream helpers #1

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18 changes: 10 additions & 8 deletions guest.js
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Original file line number Diff line number Diff line change
@@ -1,11 +1,10 @@
'use strict'

const duplexify = require('duplexify')
const { AbstractLevel, AbstractIterator } = require('abstract-level')
const eos = require('end-of-stream')
const lpstream = require('length-prefixed-stream')
const ModuleError = require('module-error')
const { input, output } = require('./tags')
const { Duplex, pipeline, finished } = require('stream')

const kExplicitClose = Symbol('explicitClose')
const kAbortRequests = Symbol('abortRequests')
Expand Down Expand Up @@ -108,10 +107,8 @@ class ManyLevelGuest extends AbstractLevel {
self[kFlushed]()
})

const proxy = duplexify()
proxy.setWritable(decode)
proxy.setReadable(encode)
eos(proxy, cleanup)
const proxy = Duplex.from({ writable: decode, readable: encode })
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This requires node 16.8.0 and probably can't be browserified either because readable-stream is behind

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Although, on the browser point, perhaps it's time to let go of the old and build something web stream-based

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Sad but true... to both.

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@ronag ronag Mar 21, 2022 •
edited
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Can we use Duplex.from if available and otherwise fallback to duplexify?

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A few things I want to do first:

  1. Benchmark Duplex.from, I didn't try that yet. And design a more suitable benchmark, because I've focused mainly on iterators so far, less on one-of operations like put() and get(). And swap level for memory-level to remove fs from the equation. And bypass net sockets.
  2. Check compat with length-prefixed-stream which uses readable-stream and therefore doesn't satisfy core's willEmitClose logic. And length-prefixed-stream has its own destroy() 😞. Not sure what the effect is though, if any. Can you help with that?

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I need some time to think about which flavor of streams to go with. It's a difficult question.

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@ronag ronag Mar 21, 2022 •
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I would personally not use readable-stream or any of the non-core helpers in production. But that's just my opinion. IMHO They are basically unmaintained and have lots of bugs.

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Indirectly that unfortunately includes any lib that uses them.

finished(proxy, cleanup)
this[kRpcStream] = proxy
return proxy

Expand Down Expand Up @@ -312,7 +309,7 @@ class ManyLevelGuest extends AbstractLevel {
this[kAbortRequests]('Aborted on database close()', 'LEVEL_DATABASE_NOT_OPEN')

if (this[kRpcStream]) {
eos(this[kRpcStream], () => {
finished(this[kRpcStream], () => {
this[kRpcStream] = null
this._close(cb)
})
Expand All @@ -330,7 +327,12 @@ class ManyLevelGuest extends AbstractLevel {
// For tests only so does not need error handling
this[kExplicitClose] = false
const remote = this[kRemote]()
remote.pipe(this.connect()).pipe(remote)
pipeline(
remote,
this.connect(),
remote,
() => {}
)
} else if (this[kExplicitClose]) {
throw new ModuleError('Cannot reopen many-level database after close()', {
code: 'LEVEL_NOT_SUPPORTED'
Expand Down
7 changes: 3 additions & 4 deletions host.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,7 @@

const lpstream = require('length-prefixed-stream')
const ModuleError = require('module-error')
const eos = require('end-of-stream')
const duplexify = require('duplexify')
const { Duplex, finished } = require('stream')
const { input, output } = require('./tags')

const rangeOptions = new Set(['gt', 'gte', 'lt', 'lte'])
Expand Down Expand Up @@ -60,7 +59,7 @@ function createRpcStream (db, options, streamOptions) {
const readonly = options.readonly
const decode = lpstream.decode()
const encode = lpstream.encode()
const stream = duplexify(decode, encode)
const stream = Duplex.from({ writable: decode, readable: encode })

const preput = options.preput
const predel = options.predel
Expand All @@ -85,7 +84,7 @@ function createRpcStream (db, options, streamOptions) {

const iterators = new Map()

eos(stream, function () {
finished(stream, function () {
for (const iterator of iterators.values()) {
iterator.close()
}
Expand Down
2 changes: 0 additions & 2 deletions package.json
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Expand Up @@ -26,8 +26,6 @@
],
"dependencies": {
"abstract-level": "^1.0.3",
"duplexify": "^4.1.1",
"end-of-stream": "^1.1.0",
"length-prefixed-stream": "^2.0.0",
"module-error": "^1.0.2",
"protocol-buffers-encodings": "^1.1.0"
Expand Down