FIX #347 add ability to add arbitrary stuff from the classpath. Only

src/main/scala/com/typesafe/sbt/packager/MappingsHelper.scala

@@ -2,11 +2,22 @@ package com.typesafe.sbt
 package packager
 
 import sbt._
+import com.typesafe.sbt.packager.archetypes.JavaAppPackaging
 
 /** A set of helper methods to simplify the writing of mappings */
 object MappingsHelper {
 
-  /** return a Seq of mappings which effect is to add a whole directory in the generated package */
+  /** 
+   * return a Seq of mappings which effect is to add a whole directory in the generated package 
+   * 
+   * @example 
+   * {{{
+   * mappings in Universal ++= directory(baseDirectory.value / "extra")
+   * }}}
+   * 
+   * @param sourceDir
+   * @return mappings
+   */
   def directory(sourceDir: File): Seq[(File, String)] = {
     val parentFile = sourceDir.getParentFile
     if (parentFile != null)
@@ -15,22 +26,103 @@ object MappingsHelper {
       sourceDir.*** pair basic
   }
 
-  /** It lightens the build file if one wants to give a string instead of file. */
+  /**
+   * It lightens the build file if one wants to give a string instead of file.
+   * 
+   * @example 
+   * {{{
+   * mappings in Universal ++= directory("extra")
+   * }}}
+   * 
+   * @param sourceDir
+   * @return mappings
+   */
   def directory(sourceDir: String): Seq[(File, String)] = {
     directory(file(sourceDir))
   }
 
   /**
    * return a Seq of mappings which effect is to add the content of directory in the generated package,
-   *  excluding the directory itself
+   * excluding the directory itself.
+   * 
+   * @example 
+   * {{{
+   * mappings in Universal ++= sourceDir(baseDirectory.value / "extra")
+   * }}}
+   * 
+   * @param sourceDir
+   * @return mappings
    */
   def contentOf(sourceDir: File): Seq[(File, String)] = {
     (sourceDir.*** --- sourceDir) pair relativeTo(sourceDir)
   }
 
-  /** It lightens the build file if one wants to give a string instead of file. */
+  /** 
+   * It lightens the build file if one wants to give a string instead of file. 
+   *  
+   * @example
+   * {{{
+   * mappings in Universal ++= sourceDir("extra")
+   * }}}
+   *  
+   * @param sourceDir as string representation
+   * @return mappings
+   */
   def contentOf(sourceDir: String): Seq[(File, String)] = {
     contentOf(file(sourceDir))
   }
+
+  /**
+   * Create mappings from your classpath. For example if you want to add additional
+   * dependencies, like test or model.
+   *
+   *
+   * @example Add all test artifacts to a separated test folder
+   * {{{
+   * mappings in Universal ++= fromClasspath((managedClasspath in Test).value, target = "test")
+   * }}}
+   *
+   * @param entries
+   * @param target
+   * @return a list of mappings
+   */
+  def fromClasspath(entries: Seq[Attributed[File]], target: String): Seq[(File, String)] = {
+    fromClasspath(entries, target, _ => true)
+  }
+
+  /**
+   * Create mappings from your classpath. For example if you want to add additional
+   * dependencies, like test or model. You can also filter the artifacts that should
+   * be mapped to mappings.
+   * 
+   * @example Filter all osgi bundles 
+   * {{{
+   * mappings in Universal ++= fromClasspath(
+   *    (managedClasspath in Runtime).value,
+   *    "osgi", 
+   *    artifact => artifact.`type` == "bundle"
+   * )
+   * }}}
+   *
+   *
+   * @param entries from where mappings should be created from
+   * @param target folder, e.g. `model`. Must not end with a slash
+   * @param includeArtifact function to determine if an artifact should result in a mapping
+   * @param includeOnNoArtifact default is false. When there's no Artifact meta data remove it
+   */
+  def fromClasspath(
+    entries: Seq[Attributed[File]],
+    target: String,
+    includeArtifact: Artifact => Boolean,
+    includeOnNoArtifact: Boolean = false): Seq[(File, String)] = {
+
+    entries
+      .filter(attr => attr.get(sbt.Keys.artifact.key) map includeArtifact getOrElse includeOnNoArtifact)
+      .map { attribute =>
+        val file = attribute.data
+        file -> s"$target/${file.getName}"
+      }
+  }
+
 }