Refactor CommitCommand to improve readability

Change-Id: Id3cac81cd32c07f677b7f669d58e32b5290e1790
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java

@@ -20,6 +20,7 @@
 import java.util.List;
 
 import org.eclipse.jgit.api.errors.AbortedByHookException;
+import org.eclipse.jgit.api.errors.CanceledException;
 import org.eclipse.jgit.api.errors.ConcurrentRefUpdateException;
 import org.eclipse.jgit.api.errors.EmptyCommitException;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -36,6 +37,8 @@
 import org.eclipse.jgit.dircache.DirCacheBuilder;
 import org.eclipse.jgit.dircache.DirCacheEntry;
 import org.eclipse.jgit.dircache.DirCacheIterator;
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.errors.UnmergedPathException;
 import org.eclipse.jgit.hooks.CommitMsgHook;
 import org.eclipse.jgit.hooks.Hooks;
@@ -230,26 +233,59 @@ public RevCommit call() throws GitAPIException, AbortedByHookException,
 				if (insertChangeId)
 					insertChangeId(indexTreeId);
 
-				// Check for empty commits
+				checkIfEmpty(rw, headId, indexTreeId);
-				if (headId != null && !allowEmpty.booleanValue()) {
-					RevCommit headCommit = rw.parseCommit(headId);
-					headCommit.getTree();
-					if (indexTreeId.equals(headCommit.getTree())) {
-						throw new EmptyCommitException(
-								JGitText.get().emptyCommit);
-					}
-				}
 
 				// Create a Commit object, populate it and write it
 				CommitBuilder commit = new CommitBuilder();
 				commit.setCommitter(committer);
 				commit.setAuthor(author);
 				commit.setMessage(message);
-
 				commit.setParentIds(parents);
 				commit.setTreeId(indexTreeId);
 
 				if (signCommit.booleanValue()) {
+					sign(commit);
+				}
+
+				ObjectId commitId = odi.insert(commit);
+				odi.flush();
+				revCommit = rw.parseCommit(commitId);
+
+				updateRef(state, headId, revCommit, commitId);
+			} finally {
+				index.unlock();
+			}
+			try {
+				Hooks.postCommit(repo, hookOutRedirect.get(PostCommitHook.NAME),
+						hookErrRedirect.get(PostCommitHook.NAME)).call();
+			} catch (Exception e) {
+				log.error(MessageFormat.format(
+						JGitText.get().postCommitHookFailed, e.getMessage()),
+						e);
+			}
+			return revCommit;
+		} catch (UnmergedPathException e) {
+			throw new UnmergedPathsException(e);
+		} catch (IOException e) {
+			throw new JGitInternalException(
+					JGitText.get().exceptionCaughtDuringExecutionOfCommitCommand, e);
+		}
+	}
+
+	private void checkIfEmpty(RevWalk rw, ObjectId headId, ObjectId indexTreeId)
+			throws EmptyCommitException, MissingObjectException,
+			IncorrectObjectTypeException, IOException {
+		if (headId != null && !allowEmpty.booleanValue()) {
+			RevCommit headCommit = rw.parseCommit(headId);
+			headCommit.getTree();
+			if (indexTreeId.equals(headCommit.getTree())) {
+				throw new EmptyCommitException(JGitText.get().emptyCommit);
+			}
+		}
+	}
+
+	private void sign(CommitBuilder commit) throws ServiceUnavailableException,
+			CanceledException, UnsupportedSigningFormatException {
 		if (gpgSigner == null) {
 			throw new ServiceUnavailableException(
 					JGitText.get().signingServiceUnavailable);
@@ -268,10 +304,9 @@ public RevCommit call() throws GitAPIException, AbortedByHookException,
 		}
 	}
 
-				ObjectId commitId = odi.insert(commit);
+	private void updateRef(RepositoryState state, ObjectId headId,
-				odi.flush();
+			RevCommit revCommit, ObjectId commitId)
-
+			throws ConcurrentRefUpdateException, IOException {
-				revCommit = rw.parseCommit(commitId);
 		RefUpdate ru = repo.updateRef(Constants.HEAD);
 		ru.setNewObjectId(commitId);
 		if (!useDefaultReflogMessage) {
@@ -283,10 +318,11 @@ public RevCommit call() throws GitAPIException, AbortedByHookException,
 			ru.setRefLogMessage(prefix + revCommit.getShortMessage(),
 					false);
 		}
-				if (headId != null)
+		if (headId != null) {
 			ru.setExpectedOldObjectId(headId);
-				else
+		} else {
 			ru.setExpectedOldObjectId(ObjectId.zeroId());
+		}
 		Result rc = ru.forceUpdate();
 		switch (rc) {
 		case NEW:
@@ -317,24 +353,6 @@ public RevCommit call() throws GitAPIException, AbortedByHookException,
 					JGitText.get().updatingRefFailed, Constants.HEAD,
 					commitId.toString(), rc));
 		}
-			} finally {
-				index.unlock();
-			}
-			try {
-				Hooks.postCommit(repo, hookOutRedirect.get(PostCommitHook.NAME),
-						hookErrRedirect.get(PostCommitHook.NAME)).call();
-			} catch (Exception e) {
-				log.error(MessageFormat.format(
-						JGitText.get().postCommitHookFailed, e.getMessage()),
-						e);
-			}
-			return revCommit;
-		} catch (UnmergedPathException e) {
-			throw new UnmergedPathsException(e);
-		} catch (IOException e) {
-			throw new JGitInternalException(
-					JGitText.get().exceptionCaughtDuringExecutionOfCommitCommand, e);
-		}
 	}
 
 	private void insertChangeId(ObjectId treeId) {