show progress for imports and deletions

src/lansync.js

@@ -17,6 +17,7 @@ const readline = require('readline')
 
 const { DIRS, readJson, writeJson, toPortablePath } = require('./paths')
 const { rewireSymlinks, restoreExecutableBits } = require('./symlinks')
+const { progressGate } = require('./fsutil')
 const library = require('./library')
 const wines = require('./wines')
 const prefixes = require('./prefixes')
@@ -375,45 +376,6 @@ function ownedRoot(rel) {
   return SYNC_ROOTS.some(prefix => clean.startsWith(prefix)) ? clean : null
 }
 
-// Progress is cheap to produce and expensive to render: hashing or copying a
-// prefix can emit tens of thousands of events, and forwarding every single one
-// over IPC makes the window stutter instead of showing progress. Events are
-// rate limited to ~10/s per phase; `force` lets a caller push the value that
-// matters (the end of a unit) through immediately.
-const PROGRESS_MIN_MS = 100
-
-function progressGate(emit) {
-  let lastAt = 0
-  let pending = null
-  let timer = null
-  const flush = () => {
-    timer = null
-    if (!pending) return
-    const data = pending
-    pending = null
-    lastAt = Date.now()
-    emit(data)
-  }
-  return (data, force) => {
-    const now = Date.now()
-    if (force || now - lastAt >= PROGRESS_MIN_MS) {
-      if (timer) {
-        clearTimeout(timer)
-        timer = null
-      }
-      pending = null
-      lastAt = now
-      emit(data)
-      return
-    }
-    pending = data
-    if (!timer) {
-      timer = setTimeout(flush, PROGRESS_MIN_MS - (now - lastAt))
-      if (timer.unref) timer.unref()
-    }
-  }
-}
-
 async function mapLimit(items, limit, fn) {
   const out = new Array(items.length)
   let next = 0