From 232d161e99a2931137d0d5bf31c4537314b97727 Mon Sep 17 00:00:00 2001
From: James Strachan <james.strachan@gmail.com>
Date: Wed, 21 Dec 2011 10:09:55 +0000
Subject: [PATCH] added a little helper method for processing a closeable
 object which then makes sure the resource is closed (like the
 try-with-resource extension in Java 7)

---
 stdlib/ktSrc/JavaIo.kt      | 37 +++++++++++++++++++++++++++++++++++++
 testlib/test/HelloWorld.txt |  2 ++
 testlib/test/IoTest.kt      | 31 +++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 testlib/test/HelloWorld.txt
 create mode 100644 testlib/test/IoTest.kt

diff --git a/stdlib/ktSrc/JavaIo.kt b/stdlib/ktSrc/JavaIo.kt
index 71ab785f556..a710dff0c94 100644
--- a/stdlib/ktSrc/JavaIo.kt
+++ b/stdlib/ktSrc/JavaIo.kt
@@ -67,6 +67,26 @@ namespace io {
 
     inline fun readLine() : String? = stdin.readLine()
 
+    /** Uses the given resource then closes it to ensure its closed again */
+    inline fun <T: Closeable, R> T.use(block: fun(T): R) : R {
+      var closed = false
+      try {
+        return block(this)
+      } catch (e: Exception) {
+        try {
+          this.close()
+        } catch (closeException: Exception) {
+          // eat the closeException as we are already throwing the original cause
+          // and we don't want to mask the real exception
+        }
+        throw e
+      } finally {
+        if (!closed) {
+          this.close()
+        }
+      }
+    }
+
     fun InputStream.iterator() : ByteIterator =
         object: ByteIterator() {
             override val hasNext : Boolean
@@ -95,5 +115,22 @@ namespace io {
 //    inline val Reader.buffered : BufferedReader
 //        get() = if(this is BufferedReader) this else BufferedReader(this)
 
+    inline fun Reader.buffered() = BufferedReader(this)
+
     inline fun Reader.buffered(bufferSize: Int) = BufferedReader(this, bufferSize)
+
+    inline fun BufferedReader.lineIterator() : Iterator<String> = LineIterator(this)
+
+    protected class LineIterator(val reader: BufferedReader) : Iterator<String> {
+      var nextLine: String? = null
+
+      override val hasNext: Boolean
+        get() {
+          nextLine = reader.readLine()
+          return nextLine != null
+        }
+
+      override fun next(): String = nextLine.sure()
+    }
+
 }
\ No newline at end of file
diff --git a/testlib/test/HelloWorld.txt b/testlib/test/HelloWorld.txt
new file mode 100644
index 00000000000..ed81d07f67b
--- /dev/null
+++ b/testlib/test/HelloWorld.txt
@@ -0,0 +1,2 @@
+Hello
+World
\ No newline at end of file
diff --git a/testlib/test/IoTest.kt b/testlib/test/IoTest.kt
new file mode 100644
index 00000000000..2354864bd5b
--- /dev/null
+++ b/testlib/test/IoTest.kt
@@ -0,0 +1,31 @@
+namespace test.collections
+
+import std.test.*
+
+import std.io.*
+import std.util.*
+import java.io.*
+
+class IoTest() : TestSupport() {
+  val file = File("test/HelloWorld.txt")
+
+  fun testUse() {
+    val list = arrayList<String>()
+
+    val reader = FileReader(file).buffered()
+    reader.close()
+
+    /**
+    TODO compiler error?
+    reader.use<BufferedReader,Unit>{
+      val line = it.readLine()
+      if (line != null) {
+        list.add(line)
+      }
+    }
+
+    assertEquals(arrayList("Hello", "World"), list)
+    */
+  }
+
+}
\ No newline at end of file