/*
    * Copyright (C) 2010-2012, Christian Halstrick <christian.halstrick@sap.com> and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  package org.eclipse.jgit.api;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintStream;
  import java.text.MessageFormat;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.LinkedList;
  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;
  import org.eclipse.jgit.api.errors.JGitInternalException;
  import org.eclipse.jgit.api.errors.NoFilepatternException;
  import org.eclipse.jgit.api.errors.NoHeadException;
  import org.eclipse.jgit.api.errors.NoMessageException;
  import org.eclipse.jgit.api.errors.ServiceUnavailableException;
  import org.eclipse.jgit.api.errors.UnmergedPathsException;
  import org.eclipse.jgit.api.errors.UnsupportedSigningFormatException;
  import org.eclipse.jgit.api.errors.WrongRepositoryStateException;
  import org.eclipse.jgit.dircache.DirCache;
  import org.eclipse.jgit.dircache.DirCacheBuildIterator;
  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;
  import org.eclipse.jgit.hooks.PostCommitHook;
  import org.eclipse.jgit.hooks.PreCommitHook;
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.lib.CommitBuilder;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.FileMode;
  import org.eclipse.jgit.lib.GpgConfig;
  import org.eclipse.jgit.lib.GpgConfig.GpgFormat;
  import org.eclipse.jgit.lib.GpgObjectSigner;
  import org.eclipse.jgit.lib.GpgSigner;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.ObjectInserter;
  import org.eclipse.jgit.lib.PersonIdent;
  import org.eclipse.jgit.lib.Ref;
  import org.eclipse.jgit.lib.RefUpdate;
  import org.eclipse.jgit.lib.RefUpdate.Result;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.lib.RepositoryState;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevObject;
  import org.eclipse.jgit.revwalk.RevTag;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.transport.CredentialsProvider;
  import org.eclipse.jgit.treewalk.CanonicalTreeParser;
  import org.eclipse.jgit.treewalk.FileTreeIterator;
  import org.eclipse.jgit.treewalk.TreeWalk;
  import org.eclipse.jgit.treewalk.TreeWalk.OperationType;
  import org.eclipse.jgit.util.ChangeIdUtil;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A class used to execute a {@code Commit} command. It has setters for all
   * supported options and arguments of this command and a {@link #call()} method
   * to finally execute the command.
   *
   * @see <a
   *      href="http://www.kernel.org/pub/software/scm/git/docs/git-commit.html"
   *      >Git documentation about Commit</a>
   */
  public class CommitCommand extends GitCommand<RevCommit> {
  	private static final Logger log = LoggerFactory
  			.getLogger(CommitCommand.class);
  
  	private PersonIdent author;
  
  	private PersonIdent committer;
  
  	private String message;
  
  	private boolean all;
  
  	private List<String> only = new ArrayList<>();
  
  	private boolean[] onlyProcessed;
 
 	private boolean amend;
 
 	private boolean insertChangeId;
 
 	/**
 	 * parents this commit should have. The current HEAD will be in this list
 	 * and also all commits mentioned in .git/MERGE_HEAD
 	 */
 	private List<ObjectId> parents = new LinkedList<>();
 
 	private String reflogComment;
 
 	private boolean useDefaultReflogMessage = true;
 
 	/**
 	 * Setting this option bypasses the pre-commit and commit-msg hooks.
 	 */
 	private boolean noVerify;
 
 	private HashMap<String, PrintStream> hookOutRedirect = new HashMap<>(3);
 
 	private HashMap<String, PrintStream> hookErrRedirect = new HashMap<>(3);
 
 	private Boolean allowEmpty;
 
 	private Boolean signCommit;
 
 	private String signingKey;
 
 	private GpgSigner gpgSigner;
 
 	private GpgConfig gpgConfig;
 
 	private CredentialsProvider credentialsProvider;
 
 	/**
 	 * Constructor for CommitCommand
 	 *
 	 * @param repo
 	 *            the {@link org.eclipse.jgit.lib.Repository}
 	 */
 	protected CommitCommand(Repository repo) {
 		super(repo);
 		this.credentialsProvider = CredentialsProvider.getDefault();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 * <p>
 	 * Executes the {@code commit} command with all the options and parameters
 	 * collected by the setter methods of this class. Each instance of this
 	 * class should only be used for one invocation of the command (means: one
 	 * call to {@link #call()})
 	 *
 	 * @throws ServiceUnavailableException
 	 *             if signing service is not available e.g. since it isn't
 	 *             installed
 	 */
 	@Override
 	public RevCommit call() throws GitAPIException, AbortedByHookException,
 			ConcurrentRefUpdateException, NoHeadException, NoMessageException,
 			ServiceUnavailableException, UnmergedPathsException,
 			WrongRepositoryStateException {
 		checkCallable();
 		Collections.sort(only);
 
 		try (RevWalk rw = new RevWalk(repo)) {
 			RepositoryState state = repo.getRepositoryState();
 			if (!state.canCommit())
 				throw new WrongRepositoryStateException(MessageFormat.format(
 						JGitText.get().cannotCommitOnARepoWithState,
 						state.name()));
 
 			if (!noVerify) {
 				Hooks.preCommit(repo, hookOutRedirect.get(PreCommitHook.NAME),
 						hookErrRedirect.get(PreCommitHook.NAME))
 						.call();
 			}
 
 			processOptions(state, rw);
 
 			if (all && !repo.isBare()) {
 				try (Git git = new Git(repo)) {
 					git.add().addFilepattern(".") //$NON-NLS-1$
 							.setUpdate(true).call();
 				} catch (NoFilepatternException e) {
 					// should really not happen
 					throw new JGitInternalException(e.getMessage(), e);
 				}
 			}
 
 			Ref head = repo.exactRef(Constants.HEAD);
 			if (head == null)
 				throw new NoHeadException(
 						JGitText.get().commitOnRepoWithoutHEADCurrentlyNotSupported);
 
 			// determine the current HEAD and the commit it is referring to
 			ObjectId headId = repo.resolve(Constants.HEAD + "^{commit}"); //$NON-NLS-1$
 			if (headId == null && amend)
 				throw new WrongRepositoryStateException(
 						JGitText.get().commitAmendOnInitialNotPossible);
 
 			if (headId != null)
 				if (amend) {
 					RevCommit previousCommit = rw.parseCommit(headId);
 					for (RevCommit p : previousCommit.getParents())
 						parents.add(p.getId());
 					if (author == null)
 						author = previousCommit.getAuthorIdent();
 				} else {
 					parents.add(0, headId);
 				}
 
 			if (!noVerify) {
 				message = Hooks
 						.commitMsg(repo,
 								hookOutRedirect.get(CommitMsgHook.NAME),
 								hookErrRedirect.get(CommitMsgHook.NAME))
 						.setCommitMessage(message).call();
 			}
 
 			RevCommit revCommit;
 			DirCache index = repo.lockDirCache();
 			try (ObjectInserter odi = repo.newObjectInserter()) {
 				if (!only.isEmpty())
 					index = createTemporaryIndex(headId, index, rw);
 
 				// Write the index as tree to the object database. This may
 				// fail for example when the index contains unmerged paths
 				// (unresolved conflicts)
 				ObjectId indexTreeId = index.writeTree(odi);
 
 				if (insertChangeId)
 					insertChangeId(indexTreeId);
 
 				checkIfEmpty(rw, headId, indexTreeId);
 
 				// 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);
 		}
 		if (gpgSigner instanceof GpgObjectSigner) {
 			((GpgObjectSigner) gpgSigner).signObject(commit,
 					signingKey, committer, credentialsProvider,
 					gpgConfig);
 		} else {
 			if (gpgConfig.getKeyFormat() != GpgFormat.OPENPGP) {
 				throw new UnsupportedSigningFormatException(JGitText
 						.get().onlyOpenPgpSupportedForSigning);
 			}
 			gpgSigner.sign(commit, signingKey, committer,
 					credentialsProvider);
 		}
 	}
 
 	private void updateRef(RepositoryState state, ObjectId headId,
 			RevCommit revCommit, ObjectId commitId)
 			throws ConcurrentRefUpdateException, IOException {
 		RefUpdate ru = repo.updateRef(Constants.HEAD);
 		ru.setNewObjectId(commitId);
 		if (!useDefaultReflogMessage) {
 			ru.setRefLogMessage(reflogComment, false);
 		} else {
 			String prefix = amend ? "commit (amend): " //$NON-NLS-1$
 					: parents.isEmpty() ? "commit (initial): " //$NON-NLS-1$
 							: "commit: "; //$NON-NLS-1$
 			ru.setRefLogMessage(prefix + revCommit.getShortMessage(),
 					false);
 		}
 		if (headId != null) {
 			ru.setExpectedOldObjectId(headId);
 		} else {
 			ru.setExpectedOldObjectId(ObjectId.zeroId());
 		}
 		Result rc = ru.forceUpdate();
 		switch (rc) {
 		case NEW:
 		case FORCED:
 		case FAST_FORWARD: {
 			setCallable(false);
 			if (state == RepositoryState.MERGING_RESOLVED
 					|| isMergeDuringRebase(state)) {
 				// Commit was successful. Now delete the files
 				// used for merge commits
 				repo.writeMergeCommitMsg(null);
 				repo.writeMergeHeads(null);
 			} else if (state == RepositoryState.CHERRY_PICKING_RESOLVED) {
 				repo.writeMergeCommitMsg(null);
 				repo.writeCherryPickHead(null);
 			} else if (state == RepositoryState.REVERTING_RESOLVED) {
 				repo.writeMergeCommitMsg(null);
 				repo.writeRevertHead(null);
 			}
 			break;
 		}
 		case REJECTED:
 		case LOCK_FAILURE:
 			throw new ConcurrentRefUpdateException(
 					JGitText.get().couldNotLockHEAD, ru.getRef(), rc);
 		default:
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().updatingRefFailed, Constants.HEAD,
 					commitId.toString(), rc));
 		}
 	}
 
 	private void insertChangeId(ObjectId treeId) {
 		ObjectId firstParentId = null;
 		if (!parents.isEmpty())
 			firstParentId = parents.get(0);
 		ObjectId changeId = ChangeIdUtil.computeChangeId(treeId, firstParentId,
 				author, committer, message);
 		message = ChangeIdUtil.insertId(message, changeId);
 		if (changeId != null)
 			message = message.replaceAll("\nChange-Id: I" //$NON-NLS-1$
 					+ ObjectId.zeroId().getName() + "\n", "\nChange-Id: I" //$NON-NLS-1$ //$NON-NLS-2$
 					+ changeId.getName() + "\n"); //$NON-NLS-1$
 	}
 
 	private DirCache createTemporaryIndex(ObjectId headId, DirCache index,
 			RevWalk rw)
 			throws IOException {
 		ObjectInserter inserter = null;
 
 		// get DirCacheBuilder for existing index
 		DirCacheBuilder existingBuilder = index.builder();
 
 		// get DirCacheBuilder for newly created in-core index to build a
 		// temporary index for this commit
 		DirCache inCoreIndex = DirCache.newInCore();
 		DirCacheBuilder tempBuilder = inCoreIndex.builder();
 
 		onlyProcessed = new boolean[only.size()];
 		boolean emptyCommit = true;
 
 		try (TreeWalk treeWalk = new TreeWalk(repo)) {
 			treeWalk.setOperationType(OperationType.CHECKIN_OP);
 			int dcIdx = treeWalk
 					.addTree(new DirCacheBuildIterator(existingBuilder));
 			FileTreeIterator fti = new FileTreeIterator(repo);
 			fti.setDirCacheIterator(treeWalk, 0);
 			int fIdx = treeWalk.addTree(fti);
 			int hIdx = -1;
 			if (headId != null)
 				hIdx = treeWalk.addTree(rw.parseTree(headId));
 			treeWalk.setRecursive(true);
 
 			String lastAddedFile = null;
 			while (treeWalk.next()) {
 				String path = treeWalk.getPathString();
 				// check if current entry's path matches a specified path
 				int pos = lookupOnly(path);
 
 				CanonicalTreeParser hTree = null;
 				if (hIdx != -1)
 					hTree = treeWalk.getTree(hIdx, CanonicalTreeParser.class);
 
 				DirCacheIterator dcTree = treeWalk.getTree(dcIdx,
 						DirCacheIterator.class);
 
 				if (pos >= 0) {
 					// include entry in commit
 
 					FileTreeIterator fTree = treeWalk.getTree(fIdx,
 							FileTreeIterator.class);
 
 					// check if entry refers to a tracked file
 					boolean tracked = dcTree != null || hTree != null;
 					if (!tracked)
 						continue;
 
 					// for an unmerged path, DirCacheBuildIterator will yield 3
 					// entries, we only want to add one
 					if (path.equals(lastAddedFile))
 						continue;
 
 					lastAddedFile = path;
 
 					if (fTree != null) {
 						// create a new DirCacheEntry with data retrieved from
 						// disk
 						final DirCacheEntry dcEntry = new DirCacheEntry(path);
 						long entryLength = fTree.getEntryLength();
 						dcEntry.setLength(entryLength);
 						dcEntry.setLastModified(fTree.getEntryLastModifiedInstant());
 						dcEntry.setFileMode(fTree.getIndexFileMode(dcTree));
 
 						boolean objectExists = (dcTree != null
 								&& fTree.idEqual(dcTree))
 								|| (hTree != null && fTree.idEqual(hTree));
 						if (objectExists) {
 							dcEntry.setObjectId(fTree.getEntryObjectId());
 						} else {
 							if (FileMode.GITLINK.equals(dcEntry.getFileMode()))
 								dcEntry.setObjectId(fTree.getEntryObjectId());
 							else {
 								// insert object
 								if (inserter == null)
 									inserter = repo.newObjectInserter();
 								long contentLength = fTree
 										.getEntryContentLength();
 								try (InputStream inputStream = fTree
 										.openEntryStream()) {
 									dcEntry.setObjectId(inserter.insert(
 											Constants.OBJ_BLOB, contentLength,
 											inputStream));
 								}
 							}
 						}
 
 						// add to existing index
 						existingBuilder.add(dcEntry);
 						// add to temporary in-core index
 						tempBuilder.add(dcEntry);
 
 						if (emptyCommit
 								&& (hTree == null || !hTree.idEqual(fTree)
 										|| hTree.getEntryRawMode() != fTree
 												.getEntryRawMode()))
 							// this is a change
 							emptyCommit = false;
 					} else {
 						// if no file exists on disk, neither add it to
 						// index nor to temporary in-core index
 
 						if (emptyCommit && hTree != null)
 							// this is a change
 							emptyCommit = false;
 					}
 
 					// keep track of processed path
 					onlyProcessed[pos] = true;
 				} else {
 					// add entries from HEAD for all other paths
 					if (hTree != null) {
 						// create a new DirCacheEntry with data retrieved from
 						// HEAD
 						final DirCacheEntry dcEntry = new DirCacheEntry(path);
 						dcEntry.setObjectId(hTree.getEntryObjectId());
 						dcEntry.setFileMode(hTree.getEntryFileMode());
 
 						// add to temporary in-core index
 						tempBuilder.add(dcEntry);
 					}
 
 					// preserve existing entry in index
 					if (dcTree != null)
 						existingBuilder.add(dcTree.getDirCacheEntry());
 				}
 			}
 		}
 
 		// there must be no unprocessed paths left at this point; otherwise an
 		// untracked or unknown path has been specified
 		for (int i = 0; i < onlyProcessed.length; i++)
 			if (!onlyProcessed[i])
 				throw new JGitInternalException(MessageFormat.format(
 						JGitText.get().entryNotFoundByPath, only.get(i)));
 
 		// there must be at least one change
 		if (emptyCommit && !allowEmpty.booleanValue())
 			// Would like to throw a EmptyCommitException. But this would break the API
 			// TODO(ch): Change this in the next release
 			throw new JGitInternalException(JGitText.get().emptyCommit);
 
 		// update index
 		existingBuilder.commit();
 		// finish temporary in-core index used for this commit
 		tempBuilder.finish();
 		return inCoreIndex;
 	}
 
 	/**
 	 * Look an entry's path up in the list of paths specified by the --only/ -o
 	 * option
 	 *
 	 * In case the complete (file) path (e.g. "d1/d2/f1") cannot be found in
 	 * <code>only</code>, lookup is also tried with (parent) directory paths
 	 * (e.g. "d1/d2" and "d1").
 	 *
 	 * @param pathString
 	 *            entry's path
 	 * @return the item's index in <code>only</code>; -1 if no item matches
 	 */
 	private int lookupOnly(String pathString) {
 		String p = pathString;
 		while (true) {
 			int position = Collections.binarySearch(only, p);
 			if (position >= 0)
 				return position;
 			int l = p.lastIndexOf('/');
 			if (l < 1)
 				break;
 			p = p.substring(0, l);
 		}
 		return -1;
 	}
 
 	/**
 	 * Sets default values for not explicitly specified options. Then validates
 	 * that all required data has been provided.
 	 *
 	 * @param state
 	 *            the state of the repository we are working on
 	 * @param rw
 	 *            the RevWalk to use
 	 *
 	 * @throws NoMessageException
 	 *             if the commit message has not been specified
 	 * @throws UnsupportedSigningFormatException
 	 *             if the configured gpg.format is not supported
 	 */
 	private void processOptions(RepositoryState state, RevWalk rw)
 			throws NoMessageException, UnsupportedSigningFormatException {
 		if (committer == null)
 			committer = new PersonIdent(repo);
 		if (author == null && !amend)
 			author = committer;
 		if (allowEmpty == null)
 			// JGit allows empty commits by default. Only when pathes are
 			// specified the commit should not be empty. This behaviour differs
 			// from native git but can only be adapted in the next release.
 			// TODO(ch) align the defaults with native git
 			allowEmpty = (only.isEmpty()) ? Boolean.TRUE : Boolean.FALSE;
 
 		// when doing a merge commit parse MERGE_HEAD and MERGE_MSG files
 		if (state == RepositoryState.MERGING_RESOLVED
 				|| isMergeDuringRebase(state)) {
 			try {
 				parents = repo.readMergeHeads();
 				if (parents != null)
 					for (int i = 0; i < parents.size(); i++) {
 						RevObject ro = rw.parseAny(parents.get(i));
 						if (ro instanceof RevTag)
 							parents.set(i, rw.peel(ro));
 					}
 			} catch (IOException e) {
 				throw new JGitInternalException(MessageFormat.format(
 						JGitText.get().exceptionOccurredDuringReadingOfGIT_DIR,
 						Constants.MERGE_HEAD, e), e);
 			}
 			if (message == null) {
 				try {
 					message = repo.readMergeCommitMsg();
 				} catch (IOException e) {
 					throw new JGitInternalException(MessageFormat.format(
 							JGitText.get().exceptionOccurredDuringReadingOfGIT_DIR,
 							Constants.MERGE_MSG, e), e);
 				}
 			}
 		} else if (state == RepositoryState.SAFE && message == null) {
 			try {
 				message = repo.readSquashCommitMsg();
 				if (message != null)
 					repo.writeSquashCommitMsg(null /* delete */);
 			} catch (IOException e) {
 				throw new JGitInternalException(MessageFormat.format(
 						JGitText.get().exceptionOccurredDuringReadingOfGIT_DIR,
 						Constants.MERGE_MSG, e), e);
 			}
 
 		}
 		if (message == null)
 			// as long as we don't support -C option we have to have
 			// an explicit message
 			throw new NoMessageException(JGitText.get().commitMessageNotSpecified);
 
 		if (gpgConfig == null) {
 			gpgConfig = new GpgConfig(repo.getConfig());
 		}
 		if (signCommit == null) {
 			signCommit = gpgConfig.isSignCommits() ? Boolean.TRUE
 					: Boolean.FALSE;
 		}
 		if (signingKey == null) {
 			signingKey = gpgConfig.getSigningKey();
 		}
 		if (gpgSigner == null) {
 			gpgSigner = GpgSigner.getDefault();
 		}
 	}
 
 	private boolean isMergeDuringRebase(RepositoryState state) {
 		if (state != RepositoryState.REBASING_INTERACTIVE
 				&& state != RepositoryState.REBASING_MERGE)
 			return false;
 		try {
 			return repo.readMergeHeads() != null;
 		} catch (IOException e) {
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().exceptionOccurredDuringReadingOfGIT_DIR,
 					Constants.MERGE_HEAD, e), e);
 		}
 	}
 
 	/**
 	 * Set the commit message
 	 *
 	 * @param message
 	 *            the commit message used for the {@code commit}
 	 * @return {@code this}
 	 */
 	public CommitCommand setMessage(String message) {
 		checkCallable();
 		this.message = message;
 		return this;
 	}
 
 	/**
 	 * Set whether to allow to create an empty commit
 	 *
 	 * @param allowEmpty
 	 *            whether it should be allowed to create a commit which has the
 	 *            same tree as it's sole predecessor (a commit which doesn't
 	 *            change anything). By default when creating standard commits
 	 *            (without specifying paths) JGit allows to create such commits.
 	 *            When this flag is set to false an attempt to create an "empty"
 	 *            standard commit will lead to an EmptyCommitException.
 	 *            <p>
 	 *            By default when creating a commit containing only specified
 	 *            paths an attempt to create an empty commit leads to a
 	 *            {@link org.eclipse.jgit.api.errors.JGitInternalException}. By
 	 *            setting this flag to <code>true</code> this exception will not
 	 *            be thrown.
 	 * @return {@code this}
 	 * @since 4.2
 	 */
 	public CommitCommand setAllowEmpty(boolean allowEmpty) {
 		this.allowEmpty = Boolean.valueOf(allowEmpty);
 		return this;
 	}
 
 	/**
 	 * Get the commit message
 	 *
 	 * @return the commit message used for the <code>commit</code>
 	 */
 	public String getMessage() {
 		return message;
 	}
 
 	/**
 	 * Sets the committer for this {@code commit}. If no committer is explicitly
 	 * specified because this method is never called or called with {@code null}
 	 * value then the committer will be deduced from config info in repository,
 	 * with current time.
 	 *
 	 * @param committer
 	 *            the committer used for the {@code commit}
 	 * @return {@code this}
 	 */
 	public CommitCommand setCommitter(PersonIdent committer) {
 		checkCallable();
 		this.committer = committer;
 		return this;
 	}
 
 	/**
 	 * Sets the committer for this {@code commit}. If no committer is explicitly
 	 * specified because this method is never called then the committer will be
 	 * deduced from config info in repository, with current time.
 	 *
 	 * @param name
 	 *            the name of the committer used for the {@code commit}
 	 * @param email
 	 *            the email of the committer used for the {@code commit}
 	 * @return {@code this}
 	 */
 	public CommitCommand setCommitter(String name, String email) {
 		checkCallable();
 		return setCommitter(new PersonIdent(name, email));
 	}
 
 	/**
 	 * Get the committer
 	 *
 	 * @return the committer used for the {@code commit}. If no committer was
 	 *         specified {@code null} is returned and the default
 	 *         {@link org.eclipse.jgit.lib.PersonIdent} of this repo is used
 	 *         during execution of the command
 	 */
 	public PersonIdent getCommitter() {
 		return committer;
 	}
 
 	/**
 	 * Sets the author for this {@code commit}. If no author is explicitly
 	 * specified because this method is never called or called with {@code null}
 	 * value then the author will be set to the committer or to the original
 	 * author when amending.
 	 *
 	 * @param author
 	 *            the author used for the {@code commit}
 	 * @return {@code this}
 	 */
 	public CommitCommand setAuthor(PersonIdent author) {
 		checkCallable();
 		this.author = author;
 		return this;
 	}
 
 	/**
 	 * Sets the author for this {@code commit}. If no author is explicitly
 	 * specified because this method is never called then the author will be set
 	 * to the committer or to the original author when amending.
 	 *
 	 * @param name
 	 *            the name of the author used for the {@code commit}
 	 * @param email
 	 *            the email of the author used for the {@code commit}
 	 * @return {@code this}
 	 */
 	public CommitCommand setAuthor(String name, String email) {
 		checkCallable();
 		return setAuthor(new PersonIdent(name, email));
 	}
 
 	/**
 	 * Get the author
 	 *
 	 * @return the author used for the {@code commit}. If no author was
 	 *         specified {@code null} is returned and the default
 	 *         {@link org.eclipse.jgit.lib.PersonIdent} of this repo is used
 	 *         during execution of the command
 	 */
 	public PersonIdent getAuthor() {
 		return author;
 	}
 
 	/**
 	 * If set to true the Commit command automatically stages files that have
 	 * been modified and deleted, but new files not known by the repository are
 	 * not affected. This corresponds to the parameter -a on the command line.
 	 *
 	 * @param all
 	 *            whether to auto-stage all files that have been modified and
 	 *            deleted
 	 * @return {@code this}
 	 * @throws JGitInternalException
 	 *             in case of an illegal combination of arguments/ options
 	 */
 	public CommitCommand setAll(boolean all) {
 		checkCallable();
 		if (all && !only.isEmpty())
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().illegalCombinationOfArguments, "--all", //$NON-NLS-1$
 					"--only")); //$NON-NLS-1$
 		this.all = all;
 		return this;
 	}
 
 	/**
 	 * Used to amend the tip of the current branch. If set to {@code true}, the
 	 * previous commit will be amended. This is equivalent to --amend on the
 	 * command line.
 	 *
 	 * @param amend
 	 *            whether to ammend the tip of the current branch
 	 * @return {@code this}
 	 */
 	public CommitCommand setAmend(boolean amend) {
 		checkCallable();
 		this.amend = amend;
 		return this;
 	}
 
 	/**
 	 * Commit dedicated path only.
 	 * <p>
 	 * This method can be called several times to add multiple paths. Full file
 	 * paths are supported as well as directory paths; in the latter case this
 	 * commits all files/directories below the specified path.
 	 *
 	 * @param only
 	 *            path to commit (with <code>/</code> as separator)
 	 * @return {@code this}
 	 */
 	public CommitCommand setOnly(String only) {
 		checkCallable();
 		if (all)
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().illegalCombinationOfArguments, "--only", //$NON-NLS-1$
 					"--all")); //$NON-NLS-1$
 		String o = only.endsWith("/") ? only.substring(0, only.length() - 1) //$NON-NLS-1$
 				: only;
 		// ignore duplicates
 		if (!this.only.contains(o))
 			this.only.add(o);
 		return this;
 	}
 
 	/**
 	 * If set to true a change id will be inserted into the commit message
 	 *
 	 * An existing change id is not replaced. An initial change id (I000...)
 	 * will be replaced by the change id.
 	 *
 	 * @param insertChangeId
 	 *            whether to insert a change id
 	 * @return {@code this}
 	 */
 	public CommitCommand setInsertChangeId(boolean insertChangeId) {
 		checkCallable();
 		this.insertChangeId = insertChangeId;
 		return this;
 	}
 
 	/**
 	 * Override the message written to the reflog
 	 *
 	 * @param reflogComment
 	 *            the comment to be written into the reflog or <code>null</code>
 	 *            to specify that no reflog should be written
 	 * @return {@code this}
 	 */
 	public CommitCommand setReflogComment(String reflogComment) {
 		this.reflogComment = reflogComment;
 		useDefaultReflogMessage = false;
 		return this;
 	}
 
 	/**
 	 * Sets the {@link #noVerify} option on this commit command.
 	 * <p>
 	 * Both the pre-commit and commit-msg hooks can block a commit by their
 	 * return value; setting this option to <code>true</code> will bypass these
 	 * two hooks.
 	 * </p>
 	 *
 	 * @param noVerify
 	 *            Whether this commit should be verified by the pre-commit and
 	 *            commit-msg hooks.
 	 * @return {@code this}
 	 * @since 3.7
 	 */
 	public CommitCommand setNoVerify(boolean noVerify) {
 		this.noVerify = noVerify;
 		return this;
 	}
 
 	/**
 	 * Set the output stream for all hook scripts executed by this command
 	 * (pre-commit, commit-msg, post-commit). If not set it defaults to
 	 * {@code System.out}.
 	 *
 	 * @param hookStdOut
 	 *            the output stream for hook scripts executed by this command
 	 * @return {@code this}
 	 * @since 3.7
 	 */
 	public CommitCommand setHookOutputStream(PrintStream hookStdOut) {
 		setHookOutputStream(PreCommitHook.NAME, hookStdOut);
 		setHookOutputStream(CommitMsgHook.NAME, hookStdOut);
 		setHookOutputStream(PostCommitHook.NAME, hookStdOut);
 		return this;
 	}
 
 	/**
 	 * Set the error stream for all hook scripts executed by this command
 	 * (pre-commit, commit-msg, post-commit). If not set it defaults to
 	 * {@code System.err}.
 	 *
 	 * @param hookStdErr
 	 *            the error stream for hook scripts executed by this command
 	 * @return {@code this}
 	 * @since 5.6
 	 */
 	public CommitCommand setHookErrorStream(PrintStream hookStdErr) {
 		setHookErrorStream(PreCommitHook.NAME, hookStdErr);
 		setHookErrorStream(CommitMsgHook.NAME, hookStdErr);
 		setHookErrorStream(PostCommitHook.NAME, hookStdErr);
 		return this;
 	}
 
 	/**
 	 * Set the output stream for a selected hook script executed by this command
 	 * (pre-commit, commit-msg, post-commit). If not set it defaults to
 	 * {@code System.out}.
 	 *
 	 * @param hookName
 	 *            name of the hook to set the output stream for
 	 * @param hookStdOut
 	 *            the output stream to use for the selected hook
 	 * @return {@code this}
 	 * @since 4.5
 	 */
 	public CommitCommand setHookOutputStream(String hookName,
 			PrintStream hookStdOut) {
 		if (!(PreCommitHook.NAME.equals(hookName)
 				|| CommitMsgHook.NAME.equals(hookName)
 				|| PostCommitHook.NAME.equals(hookName))) {
 			throw new IllegalArgumentException(
 					MessageFormat.format(JGitText.get().illegalHookName,
 							hookName));
 		}
 		hookOutRedirect.put(hookName, hookStdOut);
 		return this;
 	}
 
 	/**
 	 * Set the error stream for a selected hook script executed by this command
 	 * (pre-commit, commit-msg, post-commit). If not set it defaults to
 	 * {@code System.err}.
 	 *
 	 * @param hookName
 	 *            name of the hook to set the output stream for
 	 * @param hookStdErr
 	 *            the output stream to use for the selected hook
 	 * @return {@code this}
 	 * @since 5.6
 	 */
 	public CommitCommand setHookErrorStream(String hookName,
 			PrintStream hookStdErr) {
 		if (!(PreCommitHook.NAME.equals(hookName)
 				|| CommitMsgHook.NAME.equals(hookName)
 				|| PostCommitHook.NAME.equals(hookName))) {
 			throw new IllegalArgumentException(MessageFormat
 					.format(JGitText.get().illegalHookName, hookName));
 		}
 		hookErrRedirect.put(hookName, hookStdErr);
 		return this;
 	}
 
 	/**
 	 * Sets the signing key
 	 * <p>
 	 * Per spec of user.signingKey: this will be sent to the GPG program as is,
 	 * i.e. can be anything supported by the GPG program.
 	 * </p>
 	 * <p>
 	 * Note, if none was set or <code>null</code> is specified a default will be
 	 * obtained from the configuration.
 	 * </p>
 	 *
 	 * @param signingKey
 	 *            signing key (maybe <code>null</code>)
 	 * @return {@code this}
 	 * @since 5.3
 	 */
 	public CommitCommand setSigningKey(String signingKey) {
 		checkCallable();
 		this.signingKey = signingKey;
 		return this;
 	}
 
 	/**
 	 * Sets whether the commit should be signed.
 	 *
 	 * @param sign
 	 *            <code>true</code> to sign, <code>false</code> to not sign and
 	 *            <code>null</code> for default behavior (read from
 	 *            configuration)
 	 * @return {@code this}
 	 * @since 5.3
 	 */
 	public CommitCommand setSign(Boolean sign) {
 		checkCallable();
 		this.signCommit = sign;
 		return this;
 	}
 
 	/**
 	 * Sets the {@link GpgSigner} to use if the commit is to be signed.
 	 *
 	 * @param signer
 	 *            to use; if {@code null}, the default signer will be used
 	 * @return {@code this}
 	 * @since 5.11
 	 */
 	public CommitCommand setGpgSigner(GpgSigner signer) {
 		checkCallable();
 		this.gpgSigner = signer;
 		return this;
 	}
 
 	/**
 	 * Sets an external {@link GpgConfig} to use. Whether it will be used is at
 	 * the discretion of the {@link #setGpgSigner(GpgSigner)}.
 	 *
 	 * @param config
 	 *            to set; if {@code null}, the config will be loaded from the
 	 *            git config of the repository
 	 * @return {@code this}
 	 * @since 5.11
 	 */
 	public CommitCommand setGpgConfig(GpgConfig config) {
 		checkCallable();
 		this.gpgConfig = config;
 		return this;
 	}
 
 	/**
 	 * Sets a {@link CredentialsProvider}
 	 *
 	 * @param credentialsProvider
 	 *            the provider to use when querying for credentials (eg., during
 	 *            signing)
 	 * @since 5.3
 	 */
 	public void setCredentialsProvider(
 			CredentialsProvider credentialsProvider) {
 		this.credentialsProvider = credentialsProvider;
 	}
 }