From 8f044e6b77fc2ae4d0d468febe9eb1e30daf5770 Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Fri, 15 Jun 2018 19:26:02 +0100
Subject: [PATCH] Extract HeadWriter

---
 .../net/kemitix/gitdb/impl/GitDBRepo.java     | 22 ++-----
 .../net/kemitix/gitdb/impl/HeadWriter.java    | 62 +++++++++++++++++++
 2 files changed, 66 insertions(+), 18 deletions(-)
 create mode 100644 src/main/java/net/kemitix/gitdb/impl/HeadWriter.java

diff --git a/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java b/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java
index 1eb03c1..c7e1102 100644
--- a/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java
+++ b/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java
@@ -26,8 +26,6 @@ import org.eclipse.jgit.lib.*;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
-import java.nio.file.Files;
-import java.nio.file.Path;
 import java.util.*;
 
 /**
@@ -42,6 +40,7 @@ class GitDBRepo {
     private final KeyWriter keyWriter;
     private final CommitWriter commitWriter;
     private final KeyRemover keyRemover;
+    private final HeadWriter headWriter;
 
     /**
      * Creates a new instance of this class.
@@ -54,6 +53,7 @@ class GitDBRepo {
         keyWriter = new KeyWriter(repository);
         commitWriter = new CommitWriter(repository);
         keyRemover = new KeyRemover(repository);
+        headWriter = new HeadWriter(repository);
     }
 
     /**
@@ -120,20 +120,6 @@ class GitDBRepo {
         return commitWriter.write(treeId, branchRef, message, userName, userEmailAddress);
     }
 
-    private Ref writeHead(
-            final String branchName,
-            final ObjectId commitId
-    ) throws IOException {
-        final Path branchRefPath = repository
-                .getDirectory()
-                .toPath()
-                .resolve(branchName)
-                .toAbsolutePath();
-        final byte[] commitIdBytes = commitId.name().getBytes(StandardCharsets.UTF_8);
-        Files.write(branchRefPath, commitIdBytes);
-        return repository.findRef(branchName);
-    }
-
     /**
      * Reads a value from the branch with the given key.
      *
@@ -191,7 +177,7 @@ class GitDBRepo {
             final String userEmailAddress
     ) throws IOException {
         final ObjectId commitId = insertCommit(tree, message, userName, userEmailAddress, branchRef);
-        return writeHead(branchRef.getName(), commitId);
+        return headWriter.write(branchRef.getName(), commitId);
     }
 
     /**
@@ -237,6 +223,6 @@ class GitDBRepo {
      * @throws IOException error writing the branch
      */
     Ref createBranch(final Ref branchRef, final String name) throws IOException {
-        return writeHead(branchRef.getName(), branchRef.getObjectId());
+        return headWriter.write(branchRef.getName(), branchRef.getObjectId());
     }
 }
diff --git a/src/main/java/net/kemitix/gitdb/impl/HeadWriter.java b/src/main/java/net/kemitix/gitdb/impl/HeadWriter.java
new file mode 100644
index 0000000..39f2107
--- /dev/null
+++ b/src/main/java/net/kemitix/gitdb/impl/HeadWriter.java
@@ -0,0 +1,62 @@
+/*
+  The MIT License (MIT)
+
+  Copyright (c) 2018 Paul Campbell
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+  and associated documentation files (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
+  and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all copies
+  or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
+  AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package net.kemitix.gitdb.impl;
+
+import lombok.RequiredArgsConstructor;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+/**
+ * Writes the head.
+ *
+ * @author Paul Campbell (pcampbell@kemitix.net)
+ */
+@RequiredArgsConstructor
+class HeadWriter {
+
+    private final Repository repository;
+
+    /**
+     * Writes the head for the named branch for the given commit.
+     *
+     * @param branchName the branch name
+     * @param commitId   the commit to point the branch at
+     * @return the Ref of the new branch
+     * @throws IOException error writing branch head
+     */
+    Ref write(final String branchName, final ObjectId commitId) throws IOException {
+        final Path branchRefPath = repository
+                .getDirectory()
+                .toPath()
+                .resolve(branchName)
+                .toAbsolutePath();
+        final byte[] commitIdBytes = commitId.name().getBytes(StandardCharsets.UTF_8);
+        Files.write(branchRefPath, commitIdBytes);
+        return repository.findRef(branchName);
+    }
+}