Refactor reading and writing heads in Repository

Add private methods which are used for reading and writing MERGE_HEAD
and CHERRY_PICK_HEAD files, as suggested in the comments on change
I947967fdc2f1d55016c95106b104c2afcc9797a1.

Change-Id: If4617a05ee57054b8b1fcba36a06a641340ecc0e
Signed-off-by: Robin Stocker <robin@nibor.org>

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
index 4847a5dbf5d18f8592b35b47557d51c20b9839f5..aab8a8e619388502838eec28da9ac0600b2b9a85 100644 (file)
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
@@ -1158,15 +1158,8 @@ public abstract class Repository {
                if (isBare() || getDirectory() == null)
                        throw new NoWorkTreeException();
 
-               File mergeHeadFile = new File(getDirectory(), Constants.MERGE_HEAD);
-               byte[] raw;
-               try {
-                       raw = IO.readFully(mergeHeadFile);
-               } catch (FileNotFoundException notFound) {
-                       return null;
-               }
-
-               if (raw.length == 0)
+               byte[] raw = readGitDirectoryFile(Constants.MERGE_HEAD);
+               if (raw == null)
                        return null;
 
                LinkedList<ObjectId> heads = new LinkedList<ObjectId>();
@@ -1190,21 +1183,7 @@ public abstract class Repository {
         * @throws IOException
         */
        public void writeMergeHeads(List<ObjectId> heads) throws IOException {
-               File mergeHeadFile = new File(gitDir, Constants.MERGE_HEAD);
-               if (heads != null) {
-                       BufferedOutputStream bos = new BufferedOutputStream(
-                                       new FileOutputStream(mergeHeadFile));
-                       try {
-                               for (ObjectId id : heads) {
-                                       id.copyTo(bos);
-                                       bos.write('\n');
-                               }
-                       } finally {
-                               bos.close();
-                       }
-               } else {
-                       FileUtils.delete(mergeHeadFile);
-               }
+               writeHeadsFile(heads, Constants.MERGE_HEAD);
        }
 
        /**
@@ -1223,16 +1202,8 @@ public abstract class Repository {
                if (isBare() || getDirectory() == null)
                        throw new NoWorkTreeException();
 
-               File mergeHeadFile = new File(getDirectory(),
-                               Constants.CHERRY_PICK_HEAD);
-               byte[] raw;
-               try {
-                       raw = IO.readFully(mergeHeadFile);
-               } catch (FileNotFoundException notFound) {
-                       return null;
-               }
-
-               if (raw.length == 0)
+               byte[] raw = readGitDirectoryFile(Constants.CHERRY_PICK_HEAD);
+               if (raw == null)
                        return null;
 
                return ObjectId.fromString(raw, 0);
@@ -1248,18 +1219,54 @@ public abstract class Repository {
         * @throws IOException
         */
        public void writeCherryPickHead(ObjectId head) throws IOException {
-               File cherryPickHeadFile = new File(gitDir, Constants.CHERRY_PICK_HEAD);
-               if (head != null) {
+               List<ObjectId> heads = (head != null) ? Collections.singletonList(head)
+                               : null;
+               writeHeadsFile(heads, Constants.CHERRY_PICK_HEAD);
+       }
+
+       /**
+        * Read a file from the git directory.
+        *
+        * @param filename
+        * @return the raw contents or null if the file doesn't exist or is empty
+        * @throws IOException
+        */
+       private byte[] readGitDirectoryFile(String filename) throws IOException {
+               File file = new File(getDirectory(), filename);
+               try {
+                       byte[] raw = IO.readFully(file);
+                       return raw.length > 0 ? raw : null;
+               } catch (FileNotFoundException notFound) {
+                       return null;
+               }
+       }
+
+       /**
+        * Write the given heads to a file in the git directory.
+        *
+        * @param heads
+        *            a list of object ids to write or null if the file should be
+        *            deleted.
+        * @param filename
+        * @throws FileNotFoundException
+        * @throws IOException
+        */
+       private void writeHeadsFile(List<ObjectId> heads, String filename)
+                       throws FileNotFoundException, IOException {
+               File headsFile = new File(getDirectory(), filename);
+               if (heads != null) {
                        BufferedOutputStream bos = new BufferedOutputStream(
-                                       new FileOutputStream(cherryPickHeadFile));
+                                       new FileOutputStream(headsFile));
                        try {
-                               head.copyTo(bos);
-                               bos.write('\n');
+                               for (ObjectId id : heads) {
+                                       id.copyTo(bos);
+                                       bos.write('\n');
+                               }
                        } finally {
                                bos.close();
                        }
                } else {
-                       FileUtils.delete(cherryPickHeadFile, FileUtils.SKIP_MISSING);
+                       FileUtils.delete(headsFile, FileUtils.SKIP_MISSING);
                }
        }
 }