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Don't use Set[Incomplete] 

It's very expensive to compute the hash code of a deeply nested
Incomplete. To prevent a loop, we only want to check for object equality
which we can do with IdentityHashMap
This commit is contained in:
Ethan Atkins 2019-06-12 17:17:46 -07:00
parent cf9a5f283f
commit 968e83380a
1 changed files with 13 additions and 8 deletions
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21
main/src/main/scala/sbt/internal/Aggregation.scala
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@ -9,6 +9,7 @@ package sbt
package internal
import java.text.DateFormat
import java.util.{ Collections, IdentityHashMap }
import Def.ScopedKey
import Keys.{ showSuccess, showTiming, timingFormat }
@ -114,19 +115,23 @@ object Aggregation {
)(implicit display: Show[ScopedKey[_]]): State = {
val complete = timedRun[T](s, ts, extra)
showRun(complete, show)
@tailrec def findReload(
incomplete: Incomplete,
remaining: List[Incomplete],
visited: Set[Incomplete]
): Boolean = {
/*
* In the first implementation, we tried to use Set[Incomplete] for visited. It had very poor
* performance because hashCode can be expensive on Incomplete -- especially when the
* Incomplete has many instances in the causes field.
*/
lazy val visited = Collections
.newSetFromMap[Incomplete](new IdentityHashMap[Incomplete, java.lang.Boolean])
@tailrec def findReload(incomplete: Incomplete, remaining: List[Incomplete]): Boolean = {
visited.add(incomplete)
incomplete.directCause.contains(Reload) || ((remaining ::: incomplete.causes.toList)
.filterNot(visited) match {
.filterNot(visited.contains) match {
case Nil => false
case h :: tail => findReload(h, tail.filterNot(visited), visited + incomplete)
case h :: tail => findReload(h, tail.filterNot(visited.contains))
})
}
complete.results match {
case Inc(i) if findReload(i, i.causes.toList, Set.empty) =>
case Inc(i) if findReload(i, i.causes.toList) =>
val remaining = s.currentCommand.toList ::: s.remainingCommands
complete.state.copy(remainingCommands = Exec("reload", None, None) :: remaining)
case Inc(i) => complete.state.handleError(i)