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 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
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 * without modification, are permitted provided that the following
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 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
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package org.eclipse.jgit.api;

import static java.nio.charset.StandardCharsets.UTF_8;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.file.StandardCopyOption;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.PatchApplyException;
import org.eclipse.jgit.api.errors.PatchFormatException;
import org.eclipse.jgit.diff.DiffEntry.ChangeType;
import org.eclipse.jgit.diff.RawText;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.patch.FileHeader;
import org.eclipse.jgit.patch.HunkHeader;
import org.eclipse.jgit.patch.Patch;
import org.eclipse.jgit.util.FileUtils;
import org.eclipse.jgit.util.IO;

Apply a patch to files and/or to the index.
See Also:
Git documentation about apply
Since:
2.0/**
 * Apply a patch to files and/or to the index.
 *
 * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-apply.html"
 *      >Git documentation about apply</a>
 * @since 2.0
 */
public class ApplyCommand extends GitCommand<ApplyResult> {

	private InputStream in;

	
Constructs the command if the patch is to be applied to the index.
Params:
repo – /**
	 * Constructs the command if the patch is to be applied to the index.
	 *
	 * @param repo
	 */
	ApplyCommand(Repository repo) {
		super(repo);
	}

	
Set patch
Params:
in – 
           the patch to apply
Returns:
this instance/**
	 * Set patch
	 *
	 * @param in
	 *            the patch to apply
	 * @return this instance
	 */
	public ApplyCommand setPatch(InputStream in) {
		checkCallable();
		this.in = in;
		return this;
	}

	
{@inheritDoc}
 Executes the ApplyCommand command with all the options and parameters collected by the setter methods (e.g. setPatch(InputStream) of this class. Each instance of this class should only be used for one invocation of the command. Don't call this method twice on an instance. /**
	 * {@inheritDoc}
	 * <p>
	 * Executes the {@code ApplyCommand} command with all the options and
	 * parameters collected by the setter methods (e.g.
	 * {@link #setPatch(InputStream)} of this class. Each instance of this class
	 * should only be used for one invocation of the command. Don't call this
	 * method twice on an instance.
	 */
	@Override
	public ApplyResult call() throws GitAPIException, PatchFormatException,
			PatchApplyException {
		checkCallable();
		ApplyResult r = new ApplyResult();
		try {
			final Patch p = new Patch();
			try {
				p.parse(in);
			} finally {
				in.close();
			}
			if (!p.getErrors().isEmpty())
				throw new PatchFormatException(p.getErrors());
			for (FileHeader fh : p.getFiles()) {
				ChangeType type = fh.getChangeType();
				File f = null;
				switch (type) {
				case ADD:
					f = getFile(fh.getNewPath(), true);
					apply(f, fh);
					break;
				case MODIFY:
					f = getFile(fh.getOldPath(), false);
					apply(f, fh);
					break;
				case DELETE:
					f = getFile(fh.getOldPath(), false);
					if (!f.delete())
						throw new PatchApplyException(MessageFormat.format(
								JGitText.get().cannotDeleteFile, f));
					break;
				case RENAME:
					f = getFile(fh.getOldPath(), false);
					File dest = getFile(fh.getNewPath(), false);
					try {
						FileUtils.rename(f, dest,
								StandardCopyOption.ATOMIC_MOVE);
					} catch (IOException e) {
						throw new PatchApplyException(MessageFormat.format(
								JGitText.get().renameFileFailed, f, dest), e);
					}
					break;
				case COPY:
					f = getFile(fh.getOldPath(), false);
					byte[] bs = IO.readFully(f);
					FileOutputStream fos = new FileOutputStream(getFile(
							fh.getNewPath(),
							true));
					try {
						fos.write(bs);
					} finally {
						fos.close();
					}
				}
				r.addUpdatedFile(f);
			}
		} catch (IOException e) {
			throw new PatchApplyException(MessageFormat.format(
					JGitText.get().patchApplyException, e.getMessage()), e);
		}
		setCallable(false);
		return r;
	}

	private File getFile(String path, boolean create)
			throws PatchApplyException {
		File f = new File(getRepository().getWorkTree(), path);
		if (create)
			try {
				File parent = f.getParentFile();
				FileUtils.mkdirs(parent, true);
				FileUtils.createNewFile(f);
			} catch (IOException e) {
				throw new PatchApplyException(MessageFormat.format(
						JGitText.get().createNewFileFailed, f), e);
			}
		return f;
	}

	
Params:
f – 
fh – 
Throws:
IOException – 
PatchApplyException – /**
	 * @param f
	 * @param fh
	 * @throws IOException
	 * @throws PatchApplyException
	 */
	private void apply(File f, FileHeader fh)
			throws IOException, PatchApplyException {
		RawText rt = new RawText(f);
		List<String> oldLines = new ArrayList<>(rt.size());
		for (int i = 0; i < rt.size(); i++)
			oldLines.add(rt.getString(i));
		List<String> newLines = new ArrayList<>(oldLines);
		for (HunkHeader hh : fh.getHunks()) {

			byte[] b = new byte[hh.getEndOffset() - hh.getStartOffset()];
			System.arraycopy(hh.getBuffer(), hh.getStartOffset(), b, 0,
					b.length);
			RawText hrt = new RawText(b);

			List<String> hunkLines = new ArrayList<>(hrt.size());
			for (int i = 0; i < hrt.size(); i++)
				hunkLines.add(hrt.getString(i));
			int pos = 0;
			for (int j = 1; j < hunkLines.size(); j++) {
				String hunkLine = hunkLines.get(j);
				switch (hunkLine.charAt(0)) {
				case ' ':
					if (!newLines.get(hh.getNewStartLine() - 1 + pos).equals(
							hunkLine.substring(1))) {
						throw new PatchApplyException(MessageFormat.format(
								JGitText.get().patchApplyException, hh));
					}
					pos++;
					break;
				case '-':
					if (hh.getNewStartLine() == 0) {
						newLines.clear();
					} else {
						if (!newLines.get(hh.getNewStartLine() - 1 + pos)
								.equals(hunkLine.substring(1))) {
							throw new PatchApplyException(MessageFormat.format(
									JGitText.get().patchApplyException, hh));
						}
						newLines.remove(hh.getNewStartLine() - 1 + pos);
					}
					break;
				case '+':
					newLines.add(hh.getNewStartLine() - 1 + pos,
							hunkLine.substring(1));
					pos++;
					break;
				}
			}
		}
		if (!isNoNewlineAtEndOfFile(fh))
			newLines.add(""); //$NON-NLS-1$
		if (!rt.isMissingNewlineAtEnd())
			oldLines.add(""); //$NON-NLS-1$
		if (!isChanged(oldLines, newLines))
			return; // don't touch the file
		StringBuilder sb = new StringBuilder();
		for (String l : newLines) {
			// don't bother handling line endings - if it was windows, the \r is
			// still there!
			sb.append(l).append('\n');
		}
		if (sb.length() > 0) {
			sb.deleteCharAt(sb.length() - 1);
		}
		try (Writer fw = new OutputStreamWriter(new FileOutputStream(f),
				UTF_8)) {
			fw.write(sb.toString());
		}

		getRepository().getFS().setExecute(f, fh.getNewMode() == FileMode.EXECUTABLE_FILE);
	}

	private static boolean isChanged(List<String> ol, List<String> nl) {
		if (ol.size() != nl.size())
			return true;
		for (int i = 0; i < ol.size(); i++)
			if (!ol.get(i).equals(nl.get(i)))
				return true;
		return false;
	}

	private boolean isNoNewlineAtEndOfFile(FileHeader fh) {
		List<? extends HunkHeader> hunks = fh.getHunks();
		if (hunks == null || hunks.isEmpty()) {
			return false;
		}
		HunkHeader lastHunk = hunks.get(hunks.size() - 1);
		RawText lhrt = new RawText(lastHunk.getBuffer());
		return lhrt.getString(lhrt.size() - 1)
				.equals("\\ No newline at end of file"); //$NON-NLS-1$
	}
}