Add FileCacheEntry

Previously, we were leaking the internal details of incremental
compilation to users by defining FileTree(DataView|Repository)[Stamp].
To avoid this, I introduce the new class FileCacheEntry that is quite
similar to Stamp except defined using scala Options rather than java
Optionals. The implementation class just delegates to an actual Stamp
and I provided a private[sbt] ops class that adds a
method `stamp` to FileCacheEntry. This will usually just extract the
stamp from the implementation class. This allows us to use
FileCacheEntry almost interchangeably with Stamp while still avoiding
exposing users to Stamp.

main-command/src/main/scala/sbt/BasicKeys.scala

@@ -9,13 +9,11 @@ package sbt
 
 import java.io.File
 
-import sbt.internal.util.AttributeKey
 import sbt.internal.inc.classpath.ClassLoaderCache
 import sbt.internal.server.ServerHandler
-import sbt.io.FileTreeDataView
+import sbt.internal.util.AttributeKey
 import sbt.librarymanagement.ModuleID
 import sbt.util.Level
-import xsbti.compile.analysis.Stamp
 
 object BasicKeys {
   val historyPath = AttributeKey[Option[File]](

main-command/src/main/scala/sbt/FileTreeViewConfig.scala

@@ -7,11 +7,11 @@
 
 package sbt
 import sbt.Watched.WatchSource
+import sbt.internal.FileCacheEntry
 import sbt.internal.io.{ HybridPollingFileTreeRepository, WatchServiceBackedObservable, WatchState }
+import sbt.io.FileTreeDataView.{ Observable, Observer }
 import sbt.io._
-import FileTreeDataView.{ Observable, Observer }
 import sbt.util.Logger
-import xsbti.compile.analysis.Stamp
 
 import scala.concurrent.duration._
 
@@ -19,15 +19,15 @@ import scala.concurrent.duration._
  * Configuration for viewing and monitoring the file system.
  */
 final class FileTreeViewConfig private (
-    val newDataView: () => FileTreeDataView[Stamp],
+    val newDataView: () => FileTreeDataView[FileCacheEntry],
     val newMonitor: (
-        FileTreeDataView[Stamp],
+        FileTreeDataView[FileCacheEntry],
         Seq[WatchSource],
         Logger
-    ) => FileEventMonitor[Stamp]
+    ) => FileEventMonitor[FileCacheEntry]
 )
 object FileTreeViewConfig {
-  private implicit class RepositoryOps(val repository: FileTreeRepository[Stamp]) {
+  private implicit class RepositoryOps(val repository: FileTreeRepository[FileCacheEntry]) {
     def register(sources: Seq[WatchSource]): Unit = sources foreach { s =>
       repository.register(s.base.toPath, if (s.recursive) Integer.MAX_VALUE else 0)
     }
@@ -35,10 +35,10 @@ object FileTreeViewConfig {
 
   /**
    * Create a new FileTreeViewConfig. This factory takes a generic parameter, T, that is bounded
-   * by {{{sbt.io.FileTreeDataView[Stamp]}}}. The reason for this is to ensure that a
+   * by {{{sbt.io.FileTreeDataView[FileCacheEntry]}}}. The reason for this is to ensure that a
    * sbt.io.FileTreeDataView that is instantiated by [[FileTreeViewConfig.newDataView]] can be
    * passed into [[FileTreeViewConfig.newMonitor]] without constraining the type of view to be
-   * {{{sbt.io.FileTreeDataView[Stamp]}}}.
+   * {{{sbt.io.FileTreeDataView[FileCacheEntry]}}}.
    * @param newDataView create a new sbt.io.FileTreeDataView. This value may be cached in a global
    *                    attribute
    * @param newMonitor create a new sbt.io.FileEventMonitor using the sbt.io.FileTreeDataView
@@ -46,13 +46,13 @@ object FileTreeViewConfig {
    * @tparam T the subtype of sbt.io.FileTreeDataView that is returned by [[FileTreeViewConfig.newDataView]]
    * @return a [[FileTreeViewConfig]] instance.
    */
-  def apply[T <: FileTreeDataView[Stamp]](
+  def apply[T <: FileTreeDataView[FileCacheEntry]](
       newDataView: () => T,
-      newMonitor: (T, Seq[WatchSource], Logger) => FileEventMonitor[Stamp]
+      newMonitor: (T, Seq[WatchSource], Logger) => FileEventMonitor[FileCacheEntry]
   ): FileTreeViewConfig =
     new FileTreeViewConfig(
       newDataView,
-      (view: FileTreeDataView[Stamp], sources: Seq[WatchSource], logger: Logger) =>
+      (view: FileTreeDataView[FileCacheEntry], sources: Seq[WatchSource], logger: Logger) =>
         newMonitor(view.asInstanceOf[T], sources, logger)
     )
 
@@ -71,14 +71,14 @@ object FileTreeViewConfig {
       antiEntropy: FiniteDuration
   ): FileTreeViewConfig =
     FileTreeViewConfig(
-      () => FileTreeView.DEFAULT.asDataView(Stamped.converter),
+      () => FileTreeView.DEFAULT.asDataView(FileCacheEntry.default),
-      (_: FileTreeDataView[Stamp], sources, logger) => {
+      (_: FileTreeDataView[FileCacheEntry], sources, logger) => {
         val ioLogger: sbt.io.WatchLogger = msg => logger.debug(msg.toString)
         FileEventMonitor.antiEntropy(
           new WatchServiceBackedObservable(
             WatchState.empty(Watched.createWatchService(), sources),
             delay,
-            Stamped.converter,
+            FileCacheEntry.default,
             closeService = true,
             ioLogger
           ),
@@ -98,11 +98,15 @@ object FileTreeViewConfig {
    */
   def default(antiEntropy: FiniteDuration): FileTreeViewConfig =
     FileTreeViewConfig(
-      () => FileTreeRepository.default(Stamped.converter),
+      () => FileTreeRepository.default(FileCacheEntry.default),
-      (repository: FileTreeRepository[Stamp], sources: Seq[WatchSource], logger: Logger) => {
+      (
+          repository: FileTreeRepository[FileCacheEntry],
+          sources: Seq[WatchSource],
+          logger: Logger
+      ) => {
         repository.register(sources)
-        val copied = new Observable[Stamp] {
+        val copied = new Observable[FileCacheEntry] {
-          override def addObserver(observer: Observer[Stamp]): Int =
+          override def addObserver(observer: Observer[FileCacheEntry]): Int =
             repository.addObserver(observer)
           override def removeObserver(handle: Int): Unit = repository.removeObserver(handle)
           override def close(): Unit = {} // Don't close the underlying observable
@@ -155,9 +159,9 @@ object FileTreeViewConfig {
       pollingInterval: FiniteDuration,
       pollingSources: Seq[WatchSource],
   ): FileTreeViewConfig = FileTreeViewConfig(
-    () => FileTreeRepository.hybrid(Stamped.converter, pollingSources: _*),
+    () => FileTreeRepository.hybrid(FileCacheEntry.default, pollingSources: _*),
     (
-        repository: HybridPollingFileTreeRepository[Stamp],
+        repository: HybridPollingFileTreeRepository[FileCacheEntry],
         sources: Seq[WatchSource],
         logger: Logger
     ) => {

main-command/src/main/scala/sbt/Stamped.scala

@@ -10,6 +10,7 @@ package sbt
 import java.io.{ File => JFile }
 import java.nio.file.Path
 
+import sbt.internal.FileCacheEntry
 import sbt.internal.inc.Stamper
 import sbt.io.TypedPath
 import xsbti.compile.analysis.Stamp
@@ -20,17 +21,17 @@ import xsbti.compile.analysis.Stamp
  * performance anywhere where we need to check if files have changed before doing potentially
  * expensive work.
  */
-trait Stamped {
+private[sbt] trait Stamped {
-  def stamp: Stamp
+  private[sbt] def stamp: Stamp
 }
 
 /**
  * Provides converter functions from TypedPath to [[Stamped]].
  */
-object Stamped {
+private[sbt] object Stamped {
   type File = JFile with Stamped with TypedPath
-  def file(typedPath: TypedPath, stamp: Stamp): JFile with Stamped with TypedPath =
+  def file(typedPath: TypedPath, entry: FileCacheEntry): JFile with Stamped with TypedPath =
-    new StampedFileImpl(typedPath, stamp)
+    new StampedFileImpl(typedPath, entry.stamp)
 
   /**
    * Converts a TypedPath instance to a [[Stamped]] by calculating the file hash.
@@ -47,11 +48,14 @@ object Stamped {
    * using the last modified time and all other files using the file hash.
    */
   val converter: TypedPath => Stamp = (tp: TypedPath) =>
+    if (tp.isDirectory) binaryConverter(tp)
+    else {
       tp.toPath.toString match {
         case s if s.endsWith(".jar")   => binaryConverter(tp)
         case s if s.endsWith(".class") => binaryConverter(tp)
         case _                         => sourceConverter(tp)
       }
+  }
 
   /**
    * Adds a default ordering that just delegates to the java.io.File.compareTo method.

main-command/src/main/scala/sbt/Watched.scala

@@ -18,15 +18,14 @@ import sbt.BasicCommandStrings.{
 }
 import sbt.BasicCommands.otherCommandParser
 import sbt.internal.LabeledFunctions._
-import sbt.internal.LegacyWatched
 import sbt.internal.io.{ EventMonitor, Source, WatchState }
 import sbt.internal.util.Types.const
 import sbt.internal.util.complete.{ DefaultParsers, Parser }
 import sbt.internal.util.{ AttributeKey, JLine }
+import sbt.internal.{ FileCacheEntry, LegacyWatched }
 import sbt.io.FileEventMonitor.{ Creation, Deletion, Event, Update }
 import sbt.io._
 import sbt.util.{ Level, Logger }
-import xsbti.compile.analysis.Stamp
 
 import scala.annotation.tailrec
 import scala.concurrent.duration._
@@ -147,7 +146,7 @@ object Watched {
   private[sbt] def onEvent(
       sources: Seq[WatchSource],
       projectSources: Seq[WatchSource]
-  ): Event[Stamp] => Watched.Action =
+  ): Event[FileCacheEntry] => Watched.Action =
     event =>
       if (sources.exists(_.accept(event.entry.typedPath.toPath))) Watched.Trigger
       else if (projectSources.exists(_.accept(event.entry.typedPath.toPath))) event match {
@@ -459,7 +458,7 @@ trait WatchConfig {
    *
    * @return an sbt.io.FileEventMonitor instance.
    */
-  def fileEventMonitor: FileEventMonitor[Stamp]
+  def fileEventMonitor: FileEventMonitor[FileCacheEntry]
 
   /**
    * A function that is periodically invoked to determine whether the watch should stop or
@@ -482,7 +481,7 @@ trait WatchConfig {
    * @param event the detected sbt.io.FileEventMonitor.Event.
    * @return the next [[Watched.Action Action]] to run.
    */
-  def onWatchEvent(event: Event[Stamp]): Watched.Action
+  def onWatchEvent(event: Event[FileCacheEntry]): Watched.Action
 
   /**
    * Transforms the state after the watch terminates.
@@ -538,10 +537,10 @@ object WatchConfig {
    */
   def default(
       logger: Logger,
-      fileEventMonitor: FileEventMonitor[Stamp],
+      fileEventMonitor: FileEventMonitor[FileCacheEntry],
       handleInput: InputStream => Watched.Action,
       preWatch: (Int, Boolean) => Watched.Action,
-      onWatchEvent: Event[Stamp] => Watched.Action,
+      onWatchEvent: Event[FileCacheEntry] => Watched.Action,
       onWatchTerminated: (Watched.Action, String, State) => State,
       triggeredMessage: (TypedPath, Int) => Option[String],
       watchingMessage: Int => Option[String]
@@ -556,11 +555,11 @@ object WatchConfig {
     val wm = watchingMessage
     new WatchConfig {
       override def logger: Logger = l
-      override def fileEventMonitor: FileEventMonitor[Stamp] = fem
+      override def fileEventMonitor: FileEventMonitor[FileCacheEntry] = fem
       override def handleInput(inputStream: InputStream): Watched.Action = hi(inputStream)
       override def preWatch(count: Int, lastResult: Boolean): Watched.Action =
         pw(count, lastResult)
-      override def onWatchEvent(event: Event[Stamp]): Watched.Action = owe(event)
+      override def onWatchEvent(event: Event[FileCacheEntry]): Watched.Action = owe(event)
       override def onWatchTerminated(action: Watched.Action, command: String, state: State): State =
         owt(action, command, state)
       override def triggeredMessage(typedPath: TypedPath, count: Int): Option[String] =

main-command/src/main/scala/sbt/internal/FileCacheEntry.scala

@@ -0,0 +1,62 @@
+/*
+ * sbt
+ * Copyright 2011 - 2018, Lightbend, Inc.
+ * Copyright 2008 - 2010, Mark Harrah
+ * Licensed under Apache License 2.0 (see LICENSE)
+ */
+
+package sbt
+package internal
+import java.lang
+import java.util.Optional
+
+import sbt.internal.inc.{ EmptyStamp, LastModified, Stamp }
+import sbt.io.TypedPath
+import xsbti.compile.analysis.{ Stamp => XStamp }
+
+/**
+ * Represents a cache entry for a FileTreeRepository. It can be extended to add user defined
+ * data to the FileTreeRepository cache.
+ */
+trait FileCacheEntry {
+  def hash: Option[String]
+  def lastModified: Option[Long]
+}
+object FileCacheEntry {
+  def default(typedPath: TypedPath): FileCacheEntry =
+    DelegateFileCacheEntry(Stamped.converter(typedPath))
+  private[sbt] implicit class FileCacheEntryOps(val e: FileCacheEntry) extends AnyVal {
+    private[sbt] def stamp: XStamp = e match {
+      case DelegateFileCacheEntry(s) => s
+      case _ =>
+        e.hash
+          .map(Stamp.fromString)
+          .orElse(e.lastModified.map(new LastModified(_)))
+          .getOrElse(EmptyStamp)
+    }
+  }
+
+  private case class DelegateFileCacheEntry(private val stamp: XStamp)
+      extends FileCacheEntry
+      with XStamp {
+    override def getValueId: Int = stamp.getValueId
+    override def writeStamp(): String = stamp.writeStamp()
+    override def getHash: Optional[String] = stamp.getHash
+    override def getLastModified: Optional[lang.Long] = stamp.getLastModified
+    override def hash: Option[String] = getHash match {
+      case h if h.isPresent => Some(h.get)
+      case _                => None
+    }
+    override def lastModified: Option[Long] = getLastModified match {
+      case l if l.isPresent => Some(l.get)
+      case _                => None
+    }
+    override def equals(o: Any): Boolean = o match {
+      case that: DelegateFileCacheEntry => this.stamp == that.stamp
+      case that: XStamp                 => this.stamp == that
+      case _                            => false
+    }
+    override def hashCode: Int = stamp.hashCode
+    override def toString: String = s"FileCacheEntry(hash = $hash, lastModified = $lastModified)"
+  }
+}

main-command/src/test/scala/sbt/WatchedSpec.scala

@@ -14,10 +14,10 @@ import java.util.concurrent.atomic.AtomicBoolean
 import org.scalatest.{ FlatSpec, Matchers }
 import sbt.Watched._
 import sbt.WatchedSpec._
+import sbt.internal.FileCacheEntry
 import sbt.io.FileEventMonitor.Event
 import sbt.io.{ FileEventMonitor, IO, TypedPath }
 import sbt.util.Logger
-import xsbti.compile.analysis.Stamp
 
 import scala.collection.mutable
 import scala.concurrent.duration._
@@ -27,11 +27,11 @@ class WatchedSpec extends FlatSpec with Matchers {
     private val fileTreeViewConfig = FileTreeViewConfig.default(50.millis)
     def config(
         sources: Seq[WatchSource],
-        fileEventMonitor: Option[FileEventMonitor[Stamp]] = None,
+        fileEventMonitor: Option[FileEventMonitor[FileCacheEntry]] = None,
         logger: Logger = NullLogger,
         handleInput: InputStream => Action = _ => Ignore,
         preWatch: (Int, Boolean) => Action = (_, _) => CancelWatch,
-        onWatchEvent: Event[Stamp] => Action = _ => Ignore,
+        onWatchEvent: Event[FileCacheEntry] => Action = _ => Ignore,
         triggeredMessage: (TypedPath, Int) => Option[String] = (_, _) => None,
         watchingMessage: Int => Option[String] = _ => None
     ): WatchConfig = {

main/src/main/scala/sbt/Defaults.scala

@@ -274,7 +274,7 @@ object Defaults extends BuildCommon {
       fileTreeViewConfig := FileManagement.defaultFileTreeView.value,
       fileTreeView := state.value
         .get(Keys.globalFileTreeView)
-        .getOrElse(FileTreeView.DEFAULT.asDataView(Stamped.converter)),
+        .getOrElse(FileTreeView.DEFAULT.asDataView(FileCacheEntry.default)),
       externalHooks := {
         val view = fileTreeView.value
         compileOptions =>

main/src/main/scala/sbt/Keys.scala

@@ -31,7 +31,6 @@ import sbt.librarymanagement.ivy.{ Credentials, IvyConfiguration, IvyPaths, Upda
 import sbt.testing.Framework
 import sbt.util.{ Level, Logger }
 import xsbti.compile._
-import xsbti.compile.analysis.Stamp
 
 import scala.concurrent.duration.{ Duration, FiniteDuration }
 import scala.xml.{ NodeSeq, Node => XNode }
@@ -94,14 +93,14 @@ object Keys {
   @deprecated("This is no longer used for continuous execution", "1.3.0")
   val watch = SettingKey(BasicKeys.watch)
   val suppressSbtShellNotification = settingKey[Boolean]("""True to suppress the "Executing in batch mode.." message.""").withRank(CSetting)
-  val fileTreeView = taskKey[FileTreeDataView[Stamp]]("A view of the file system")
+  val fileTreeView = taskKey[FileTreeDataView[FileCacheEntry]]("A view of the file system")
   val pollInterval = settingKey[FiniteDuration]("Interval between checks for modified sources by the continuous execution command.").withRank(BMinusSetting)
   val pollingDirectories = settingKey[Seq[Watched.WatchSource]]("Directories that cannot be cached and must always be rescanned. Typically these will be NFS mounted or something similar.").withRank(DSetting)
   val watchAntiEntropy = settingKey[FiniteDuration]("Duration for which the watch EventMonitor will ignore events for a file after that file has triggered a build.").withRank(BMinusSetting)
   val watchConfig = taskKey[WatchConfig]("The configuration for continuous execution.").withRank(BMinusSetting)
   val watchLogger = taskKey[Logger]("A logger that reports watch events.").withRank(DSetting)
   val watchHandleInput = settingKey[InputStream => Watched.Action]("Function that is periodically invoked to determine if the continous build should be stopped or if a build should be triggered. It will usually read from stdin to respond to user commands.").withRank(BMinusSetting)
-  val watchOnEvent = taskKey[Event[Stamp] => Watched.Action]("Determines how to handle a file event").withRank(BMinusSetting)
+  val watchOnEvent = taskKey[Event[FileCacheEntry] => Watched.Action]("Determines how to handle a file event").withRank(BMinusSetting)
   val watchOnTermination = taskKey[(Watched.Action, String, State) => State]("Transforms the input state after the continuous build completes.").withRank(BMinusSetting)
   val watchService = settingKey[() => WatchService]("Service to use to monitor file system changes.").withRank(BMinusSetting)
   val watchProjectSources = taskKey[Seq[Watched.WatchSource]]("Defines the sources for the sbt meta project to watch to trigger a reload.").withRank(CSetting)
@@ -457,7 +456,7 @@ object Keys {
   val (executionRoots, dummyRoots) = Def.dummy[Seq[ScopedKey[_]]]("executionRoots", "The list of root tasks for this task execution.  Roots are the top-level tasks that were directly requested to be run.")
   val state = Def.stateKey
   val streamsManager = Def.streamsManagerKey
-  private[sbt] val globalFileTreeView = AttributeKey[FileTreeDataView[Stamp]](
+  private[sbt] val globalFileTreeView = AttributeKey[FileTreeDataView[FileCacheEntry]](
     "globalFileTreeView",
     "Provides a view into the file system that may or may not cache the tree in memory",
     1000

main/src/main/scala/sbt/Main.scala

@@ -25,7 +25,6 @@ import sbt.io.syntax._
 import sbt.io.{ FileTreeDataView, IO }
 import sbt.util.{ Level, Logger, Show }
 import xsbti.compile.CompilerCache
-import xsbti.compile.analysis.Stamp
 
 import scala.annotation.tailrec
 import scala.concurrent.ExecutionContext
@@ -863,7 +862,7 @@ object BuiltinCommands {
         ()
       }
       val (_, config: FileTreeViewConfig) = extracted.runTask(Keys.fileTreeViewConfig, s)
-      val view: FileTreeDataView[Stamp] = config.newDataView()
+      val view: FileTreeDataView[FileCacheEntry] = config.newDataView()
       val newState = s.addExitHook(cleanup())
       cleanup()
       newState

main/src/main/scala/sbt/internal/ExternalHooks.scala

@@ -20,7 +20,10 @@ import scala.collection.mutable
 
 private[sbt] object ExternalHooks {
   private val javaHome = Option(System.getProperty("java.home")).map(Paths.get(_))
-  def apply(options: CompileOptions, view: FileTreeDataView[Stamp]): DefaultExternalHooks = {
+  def apply(
+      options: CompileOptions,
+      view: FileTreeDataView[FileCacheEntry]
+  ): DefaultExternalHooks = {
     import scala.collection.JavaConverters._
     val sources = options.sources()
     val cachedSources = new java.util.HashMap[File, Stamp]
@@ -30,7 +33,7 @@ private[sbt] object ExternalHooks {
       case f: File     => cachedSources.put(f, converter(f))
     }
     view match {
-      case r: FileTreeRepository[Stamp] =>
+      case r: FileTreeRepository[FileCacheEntry] =>
         r.register(options.classesDirectory.toPath, Integer.MAX_VALUE)
         options.classpath.foreach { f =>
           r.register(f.toPath, Integer.MAX_VALUE)
@@ -41,7 +44,7 @@ private[sbt] object ExternalHooks {
     options.classpath.foreach { f =>
       view.listEntries(f.toPath, Integer.MAX_VALUE, _ => true) foreach { e =>
         e.value match {
-          case Right(value) => allBinaries.put(e.typedPath.toPath.toFile, value)
+          case Right(value) => allBinaries.put(e.typedPath.toPath.toFile, value.stamp)
           case _            =>
         }
       }
@@ -49,7 +52,7 @@ private[sbt] object ExternalHooks {
       // rather than a directory.
       view.listEntries(f.toPath, -1, _ => true) foreach { e =>
         e.value match {
-          case Right(value) => allBinaries.put(e.typedPath.toPath.toFile, value)
+          case Right(value) => allBinaries.put(e.typedPath.toPath.toFile, value.stamp)
           case _            =>
         }
       }

main/src/main/scala/sbt/internal/FileManagement.scala

@@ -10,13 +10,12 @@ package sbt.internal
 import java.io.IOException
 import java.nio.file.Path
 
+import sbt.BasicCommandStrings.ContinuousExecutePrefix
 import sbt.Keys._
+import sbt._
 import sbt.io.FileTreeDataView.Entry
 import sbt.io.syntax.File
 import sbt.io.{ FileFilter, FileTreeDataView, FileTreeRepository }
-import sbt._
-import BasicCommandStrings.ContinuousExecutePrefix
-import xsbti.compile.analysis.Stamp
 
 private[sbt] object FileManagement {
   private[sbt] def defaultFileTreeView: Def.Initialize[Task[FileTreeViewConfig]] = Def.task {
@@ -52,7 +51,7 @@ private[sbt] object FileManagement {
       val view = fileTreeView.value
       val include = filter.toTask.value
       val ex = excludes.toTask.value
-      val sourceFilter: Entry[Stamp] => Boolean = (entry: Entry[Stamp]) => {
+      val sourceFilter: Entry[FileCacheEntry] => Boolean = (entry: Entry[FileCacheEntry]) => {
         val typedPath = entry.typedPath
         val file = new java.io.File(typedPath.toPath.toString) {
           override def isDirectory: Boolean = typedPath.isDirectory