src/Pure/System/components.scala

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/System/components.scala	Mon Dec 03 20:04:48 2018 +0100
@@ -0,0 +1,33 @@
+/*  Title:      Pure/Admin/components.scala
+    Author:     Makarius
+
+Isabelle system components.
+*/
+
+package isabelle
+
+
+object Components
+{
+  /* component collections */
+
+  def admin(dir: Path): Path = dir + Path.explode("Admin/components")
+
+  def contrib(dir: Path = Path.current, name: String = ""): Path =
+    dir + Path.explode("contrib") + Path.explode(name)
+
+
+  /* component directory content */
+
+  def settings(dir: Path): Path = dir + Path.explode("etc/settings")
+  def components(dir: Path): Path = dir + Path.explode("etc/components")
+
+  def check_dir(dir: Path): Boolean =
+    settings(dir).is_file || components(dir).is_file
+
+  def read_components(dir: Path): List[String] =
+    split_lines(File.read(components(dir))).filter(_.nonEmpty)
+
+  def write_components(dir: Path, lines: List[String]): Unit =
+    File.write(components(dir), terminate_lines(lines))
+}