From ad0f848bed6df7ee6d3e5d1a4e74e3eefbf45e77 Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Wed, 24 Jul 2019 18:38:19 +0100
Subject: [PATCH] Ensure file handles are always closed (#122)

* [core] Ensure files are closed even when interrupted

* [changelog] updated
---
 CHANGELOG.org                                 |  1 +
 .../kemitix/thorp/core/MD5HashGenerator.scala | 24 +++++++++----------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/CHANGELOG.org b/CHANGELOG.org
index fa0944e..d3f4d19 100644
--- a/CHANGELOG.org
+++ b/CHANGELOG.org
@@ -12,6 +12,7 @@ The format is based on [[https://keepachangelog.com/en/1.0.0/][Keep a Changelog]
 
    - Log copy and delete operations (#119)
    - Log errors with red label (#119)
+   - Ensure file handles are always closed (#122)
 
 ** Changed
 
diff --git a/core/src/main/scala/net/kemitix/thorp/core/MD5HashGenerator.scala b/core/src/main/scala/net/kemitix/thorp/core/MD5HashGenerator.scala
index 3972846..2977e92 100644
--- a/core/src/main/scala/net/kemitix/thorp/core/MD5HashGenerator.scala
+++ b/core/src/main/scala/net/kemitix/thorp/core/MD5HashGenerator.scala
@@ -5,7 +5,7 @@ import java.nio.file.Path
 import java.security.MessageDigest
 
 import net.kemitix.thorp.domain.MD5Hash
-import zio.Task
+import zio.{Task, UIO, ZManaged}
 
 import scala.collection.immutable.NumericRange
 
@@ -47,22 +47,22 @@ object MD5HashGenerator {
       offset: Long,
       endOffset: Long
   ) =
-    for {
-      fis    <- openFile(file, offset)
-      digest <- digestFile(fis, offset, endOffset)
-      _      <- closeFile(fis)
-    } yield digest
+    openFile(file, offset)
+      .use(digestFile(_, offset, endOffset))
 
   private def openFile(
       file: File,
       offset: Long
-  ) = Task {
-    val stream = new FileInputStream(file)
-    stream skip offset
-    stream
-  }
+  ) =
+    ZManaged.make {
+      Task {
+        val stream = new FileInputStream(file)
+        stream skip offset
+        stream
+      }
+    }(closeFile)
 
-  private def closeFile(fis: FileInputStream) = Task(fis.close())
+  private def closeFile(fis: FileInputStream) = UIO(fis.close())
 
   private def digestFile(
       fis: FileInputStream,