mirror of https://github.com/sbt/sbt.git
56 lines
1.8 KiB
Scala
56 lines
1.8 KiB
Scala
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package xsbt.boot
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import java.io.{File, FileFilter}
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import java.net.{URL, URLClassLoader}
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trait Provider extends NotNull
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{
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def configuration: LaunchConfiguration
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def baseDirectories: Seq[File]
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def testLoadClasses: Seq[String]
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def target: UpdateTarget.Value
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def failLabel: String
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def parentLoader: ClassLoader
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val (jars, loader) =
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{
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val (existingJars, existingLoader) = createLoader
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if(Check.needsUpdate(existingLoader, testLoadClasses))
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{
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( new Update(configuration) )(target)
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val (newJars, newLoader) = createLoader
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Check.failIfMissing(newLoader, testLoadClasses, failLabel)
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(newJars, newLoader)
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}
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else
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(existingJars, existingLoader)
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}
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def createLoader =
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{
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val jars = GetJars(baseDirectories)
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(jars, new URLClassLoader(jars.map(_.toURI.toURL).toArray, parentLoader) )
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}
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}
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object GetJars
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{
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def apply(directories: Seq[File]): Array[File] = directories.flatMap(directory => wrapNull(directory.listFiles(JarFilter))).toArray
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def wrapNull(a: Array[File]): Array[File] = if(a == null) Array() else a
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object JarFilter extends FileFilter
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{
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def accept(file: File) = !file.isDirectory && file.getName.endsWith(".jar")
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}
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}
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object Check
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{
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def failIfMissing(loader: ClassLoader, classes: Iterable[String], label: String) =
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checkTarget(loader, classes, (), missing => throw new BootException("Could not retrieve " + label + ": missing " + missing.mkString(", ")))
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def needsUpdate(loader: ClassLoader, classes: Iterable[String]) = checkTarget(loader, classes, false, x => true)
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def checkTarget[T](loader: ClassLoader, classes: Iterable[String], ifSuccess: => T, ifFailure: Iterable[String] => T): T =
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{
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def classMissing(c: String) = try { Class.forName(c, false, loader); false } catch { case e: ClassNotFoundException => true }
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val missing = classes.filter(classMissing)
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if(missing.isEmpty) ifSuccess else ifFailure(missing)
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}
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}
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