Add ApplyCommand to JGit API

Bug: 361548
CQ: 6243
Change-Id: I08e1369e142bb19f42a8d7bbb5a7d062cc8533fc
Signed-off-by: Chris Aniszczyk <zx@twitter.com>

19 files changed, 807 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A1.patch b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A1.patch
new file mode 100644
index 0000000000..7ddab882c7
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A1.patch
@@ -0,0 +1,9 @@
+diff --git a/A1 b/A1
+new file mode 100644
+index 0000000..de98044
+--- /dev/null
++++ b/A1
+@@ -0,0 +1,3 @@
++a
++b
++c
\ No newline at end of file
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A1_PostImage b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A1_PostImage
new file mode 100644
index 0000000000..de980441c3
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A1_PostImage
@@ -0,0 +1,3 @@
+a
+b
+c
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A2.patch b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A2.patch
new file mode 100644
index 0000000000..83869ce395
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A2.patch
@@ -0,0 +1,10 @@
+diff --git a/A2 b/A2
+new file mode 100644
+index 0000000..de98044
+--- /dev/null
++++ b/A2
+@@ -0,0 +1,3 @@
++a
++b
++c
+\ No newline at end of file
\ No newline at end of file
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A2_PostImage b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A2_PostImage
new file mode 100644
index 0000000000..1c943a9888
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/A2_PostImage
@@ -0,0 +1,3 @@
+a
+b
+c
\ No newline at end of file
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/D.patch b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/D.patch
new file mode 100644
index 0000000000..f7db127865
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/D.patch
@@ -0,0 +1,9 @@
+diff --git a/D b/D
+deleted file mode 100644
+index a3648a1..0000000
+--- a/D
++++ /dev/null
+@@ -1,3 +0,0 @@
+-a
+-b
+-c
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/D_PreImage b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/D_PreImage
new file mode 100644
index 0000000000..de980441c3
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/D_PreImage
@@ -0,0 +1,3 @@
+a
+b
+c
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F1.patch b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F1.patch
new file mode 100644
index 0000000000..526d381dad
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F1.patch
@@ -0,0 +1,4 @@
+@@ -2,2 +2,3 @@ a
+ b
++c
+ d
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F1_PreImage b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F1_PreImage
new file mode 100644
index 0000000000..a3648a1eba
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F1_PreImage
@@ -0,0 +1,25 @@
+a
+b
+d
+e
+f
+g
+h
+i
+j
+k
+l
+m
+n
+o
+p
+q
+r
+s
+t
+u
+v
+w
+x
+y
+z
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F2.patch b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F2.patch
new file mode 100644
index 0000000000..9930e5dbe0
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F2.patch
@@ -0,0 +1,8 @@
+diff --git a/F2 b/F2
+index a3648a1..2d44096 100644
+--- a/F2
++++ b/F2
+@@ -2,2 +2,3 @@ a
+ B
++c
+ d
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F2_PreImage b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F2_PreImage
new file mode 100644
index 0000000000..a3648a1eba
--- /dev/null
+++ b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/diff/F2_PreImage
@@ -0,0 +1,25 @@
+a
+b
+d
+e
+f
+g
+h
+i
+j
+k
+l
+m
+n
+o
+p
+q
+r
+s
+t
+u
+v
+w
+x
+y
+z
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ApplyCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ApplyCommandTest.java
new file mode 100644
index 0000000000..dceb0ec697
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ApplyCommandTest.java
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2011, 2012, Tomasz Zarna <Tomasz.Zarna@pl.ibm.com>
+ * 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.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.api;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.fail;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.eclipse.jgit.api.errors.PatchApplyException;
+import org.eclipse.jgit.api.errors.PatchFormatException;
+import org.eclipse.jgit.diff.DiffFormatterReflowTest;
+import org.eclipse.jgit.diff.RawText;
+import org.eclipse.jgit.lib.RepositoryTestCase;
+import org.junit.Test;
+
+public class ApplyCommandTest extends RepositoryTestCase {
+
+	private RawText a;
+
+	private RawText b;
+
+	private ApplyResult init(final String name) throws Exception {
+		return init(name, true, true);
+	}
+
+	private ApplyResult init(final String name, final boolean preExists,
+			final boolean postExists) throws Exception {
+		Git git = new Git(db);
+
+		if (preExists) {
+			a = new RawText(readFile(name + "_PreImage"));
+			write(new File(db.getDirectory().getParent(), name),
+					a.getString(0, a.size(), false));
+
+			git.add().addFilepattern(name).call();
+			git.commit().setMessage("PreImage").call();
+		}
+
+		if (postExists)
+			b = new RawText(readFile(name + "_PostImage"));
+
+		return git
+				.apply()
+				.setPatch(
+						DiffFormatterReflowTest.class.getResourceAsStream(name
+								+ ".patch")).call();
+	}
+
+	@Test
+	public void testAddA1() throws Exception {
+		ApplyResult result = init("A1", false, true);
+		assertEquals(1, result.getUpdatedFiles().size());
+		assertEquals(new File(db.getWorkTree(), "A1"), result.getUpdatedFiles()
+				.get(0));
+		checkFile(new File(db.getWorkTree(), "A1"),
+				b.getString(0, b.size(), false));
+	}
+
+	@Test
+	public void testAddA2() throws Exception {
+		ApplyResult result = init("A2", false, true);
+		assertEquals(1, result.getUpdatedFiles().size());
+		assertEquals(new File(db.getWorkTree(), "A2"), result.getUpdatedFiles()
+				.get(0));
+		checkFile(new File(db.getWorkTree(), "A2"),
+				b.getString(0, b.size(), false));
+	}
+
+	@Test
+	public void testDeleteD() throws Exception {
+		ApplyResult result = init("D", true, false);
+		assertEquals(1, result.getUpdatedFiles().size());
+		assertEquals(new File(db.getWorkTree(), "D"), result.getUpdatedFiles()
+				.get(0));
+		assertFalse(new File(db.getWorkTree(), "D").exists());
+	}
+
+	@Test(expected = PatchFormatException.class)
+	public void testFailureF1() throws Exception {
+		init("F1", true, false);
+	}
+
+	@Test(expected = PatchApplyException.class)
+	public void testFailureF2() throws Exception {
+		init("F2", true, false);
+	}
+
+	@Test
+	public void testModifyE() throws Exception {
+		ApplyResult result = init("E");
+		assertEquals(1, result.getUpdatedFiles().size());
+		assertEquals(new File(db.getWorkTree(), "E"), result.getUpdatedFiles()
+				.get(0));
+		checkFile(new File(db.getWorkTree(), "E"),
+				b.getString(0, b.size(), false));
+	}
+
+	@Test
+	public void testModifyX() throws Exception {
+		ApplyResult result = init("X");
+		assertEquals(1, result.getUpdatedFiles().size());
+		assertEquals(new File(db.getWorkTree(), "X"), result.getUpdatedFiles()
+				.get(0));
+		checkFile(new File(db.getWorkTree(), "X"),
+				b.getString(0, b.size(), false));
+	}
+
+	@Test
+	public void testModifyY() throws Exception {
+		ApplyResult result = init("Y");
+		assertEquals(1, result.getUpdatedFiles().size());
+		assertEquals(new File(db.getWorkTree(), "Y"), result.getUpdatedFiles()
+				.get(0));
+		checkFile(new File(db.getWorkTree(), "Y"),
+				b.getString(0, b.size(), false));
+	}
+
+	@Test
+	public void testModifyZ() throws Exception {
+		ApplyResult result = init("Z");
+		assertEquals(1, result.getUpdatedFiles().size());
+		assertEquals(new File(db.getWorkTree(), "Z"), result.getUpdatedFiles()
+				.get(0));
+		checkFile(new File(db.getWorkTree(), "Z"),
+				b.getString(0, b.size(), false));
+	}
+
+	private byte[] readFile(final String patchFile) throws IOException {
+		final InputStream in = DiffFormatterReflowTest.class
+				.getResourceAsStream(patchFile);
+		if (in == null) {
+			fail("No " + patchFile + " test vector");
+			return null; // Never happens
+		}
+		try {
+			final byte[] buf = new byte[1024];
+			final ByteArrayOutputStream temp = new ByteArrayOutputStream();
+			int n;
+			while ((n = in.read(buf)) > 0)
+				temp.write(buf, 0, n);
+			return temp.toByteArray();
+		} finally {
+			in.close();
+		}
+	}
+}
diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
index 3e9d7389a0..2f07c97acc 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
@@ -347,6 +347,8 @@ packingCancelledDuringObjectsWriting=Packing cancelled during objects writing
 packObjectCountMismatch=Pack object count mismatch: pack {0} index {1}: {2}
 packTooLargeForIndexVersion1=Pack too large for index version 1
 packWriterStatistics=Total {0,number,#0} (delta {1,number,#0}), reused {2,number,#0} (delta {3,number,#0})
+patchApplyException=Cannot apply: {0}
+patchFormatException=Format error: {0}
 pathIsNotInWorkingDir=Path is not in working dir
 pathNotConfigured=Submodule path is not configured
 peeledLineBeforeRef=Peeled line before ref.
@@ -378,6 +380,7 @@ remoteNameCantBeNull=Remote name can't be null.
 renameBranchFailedBecauseTag=Can not rename as Ref {0} is a tag
 renameBranchFailedUnknownReason=Rename failed with unknown reason
 renameBranchUnexpectedResult=Unexpected rename result {0}
+renameFileFailed=Could not rename file {0} to {1}
 renamesAlreadyFound=Renames have already been found.
 renamesBreakingModifies=Breaking apart modified file pairs
 renamesFindingByContent=Finding renames by content similarity
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
index a75bf1fdd8..068e9449e1 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
@@ -407,6 +407,8 @@ public class JGitText extends TranslationBundle {
 	/***/ public String packObjectCountMismatch;
 	/***/ public String packTooLargeForIndexVersion1;
 	/***/ public String packWriterStatistics;
+	/***/ public String patchApplyException;
+	/***/ public String patchFormatException;
 	/***/ public String pathIsNotInWorkingDir;
 	/***/ public String pathNotConfigured;
 	/***/ public String peeledLineBeforeRef;
@@ -438,6 +440,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String renameBranchFailedBecauseTag;
 	/***/ public String renameBranchFailedUnknownReason;
 	/***/ public String renameBranchUnexpectedResult;
+	/***/ public String renameFileFailed;
 	/***/ public String renamesAlreadyFound;
 	/***/ public String renamesBreakingModifies;
 	/***/ public String renamesFindingByContent;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/ApplyCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/ApplyCommand.java
new file mode 100644
index 0000000000..bd489a99aa
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/ApplyCommand.java
@@ -0,0 +1,258 @@
+/*
+ * Copyright (C) 2011, 2012, IBM Corporation and others.
+ * 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.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.api;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.MessageFormat;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.eclipse.jgit.JGitText;
+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.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 <a href="http://www.kernel.org/pub/software/scm/git/docs/git-apply.html"
+ *      >Git documentation about apply</a>
+ */
+public class ApplyCommand extends GitCommand<ApplyResult> {
+
+	private InputStream in;
+
+	/**
+	 * Constructs the command if the patch is to be applied to the index.
+	 *
+	 * @param repo
+	 */
+	ApplyCommand(Repository repo) {
+		super(repo);
+	}
+
+	/**
+	 * @param in
+	 *            the patch to apply
+	 * @return this instance
+	 */
+	public ApplyCommand setPatch(InputStream in) {
+		checkCallable();
+		this.in = in;
+		return this;
+	}
+
+	/**
+	 * 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.
+	 *
+	 * @return an {@link ApplyResult} object representing the command result
+	 */
+	public ApplyResult call() throws GitAPIException {
+		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);
+					if (!f.renameTo(dest))
+						throw new PatchApplyException(MessageFormat.format(
+								JGitText.get().renameFileFailed, f, dest));
+					break;
+				case COPY:
+					f = getFile(fh.getOldPath(), false);
+					byte[] bs = IO.readFully(f);
+					FileWriter fw = new FileWriter(getFile(fh.getNewPath(),
+							true));
+					fw.write(new String(bs));
+					fw.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 {
+				FileUtils.createNewFile(f);
+			} catch (IOException e) {
+				throw new PatchApplyException(MessageFormat.format(
+						JGitText.get().createNewFileFailed, f), e);
+			}
+		return f;
+	}
+
+	/**
+	 * @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<String>(rt.size());
+		for (int i = 0; i < rt.size(); i++)
+			oldLines.add(rt.getString(i));
+		List<String> newLines = new ArrayList<String>(oldLines);
+		for (HunkHeader hh : fh.getHunks()) {
+			StringBuilder hunk = new StringBuilder();
+			for (int j = hh.getStartOffset(); j < hh.getEndOffset(); j++)
+				hunk.append((char) hh.getBuffer()[j]);
+			RawText hrt = new RawText(hunk.toString().getBytes());
+			List<String> hunkLines = new ArrayList<String>(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 (!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("");
+		if (!rt.isMissingNewlineAtEnd())
+			oldLines.add("");
+		if (!isChanged(oldLines, newLines))
+			return; // don't touch the file
+		StringBuilder sb = new StringBuilder();
+		final String eol = rt.size() == 0
+				|| (rt.size() == 1 && rt.isMissingNewlineAtEnd()) ? "\n" : rt
+				.getEOL();
+		for (String l : newLines) {
+			sb.append(l);
+			if (eol != null)
+				sb.append(eol);
+		}
+		sb.deleteCharAt(sb.length() - 1);
+		FileWriter fw = new FileWriter(f);
+		fw.write(sb.toString());
+		fw.close();
+	}
+
+	private 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) {
+		HunkHeader lastHunk = fh.getHunks().get(fh.getHunks().size() - 1);
+		RawText lhrt = new RawText(lastHunk.getBuffer());
+		return lhrt.getString(lhrt.size() - 1).equals(
+				"\\ No newline at end of file"); //$NON-NLS-1$
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/ApplyResult.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/ApplyResult.java
new file mode 100644
index 0000000000..0c38f1b486
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/ApplyResult.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2011, 2012 IBM Corporation and others.
+ * 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.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.api;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Encapsulates the result of a {@link ApplyCommand}
+ */
+public class ApplyResult {
+
+	private List<File> updatedFiles = new ArrayList<File>();
+
+	/**
+	 * @param f
+	 *            an updated file
+	 * @return this instance
+	 */
+	public ApplyResult addUpdatedFile(File f) {
+		updatedFiles.add(f);
+		return this;
+
+	}
+
+	/**
+	 * @return updated files
+	 */
+	public List<File> getUpdatedFiles() {
+		return updatedFiles;
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java
index 597ce99b15..6c44d955f2 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java
@@ -591,6 +591,20 @@ public class Git {
 	}
 
 	/**
+	 * Returns a command object to execute a {@code apply} command
+	 *
+	 * @see <a
+	 *      href="http://www.kernel.org/pub/software/scm/git/docs/git-apply.html"
+	 *      >Git documentation about apply</a>
+	 *
+	 * @return a {@link ApplyCommand} used to collect all optional parameters
+	 *         and to finally execute the {@code apply} command
+	 */
+	public ApplyCommand apply() {
+		return new ApplyCommand(repo);
+	}
+
+	/**
 	 * @return the git repository this class is interacting with
 	 */
 	public Repository getRepository() {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/errors/PatchApplyException.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/errors/PatchApplyException.java
new file mode 100644
index 0000000000..389c776736
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/errors/PatchApplyException.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2012, IBM Corporation and others.
+ * 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.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.api.errors;
+
+/**
+ * Exception thrown when applying a patch fails
+ * 
+ * @since 2.0
+ * 
+ */
+public class PatchApplyException extends GitAPIException {
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * @param message
+	 * @param cause
+	 */
+	public PatchApplyException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	/**
+	 * @param message
+	 */
+	public PatchApplyException(String message) {
+		super(message);
+	}
+
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/errors/PatchFormatException.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/errors/PatchFormatException.java
new file mode 100644
index 0000000000..9aecaea76c
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/errors/PatchFormatException.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2012, IBM Corporation and others.
+ * 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.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.api.errors;
+
+import java.text.MessageFormat;
+import java.util.List;
+
+import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.patch.FormatError;
+
+/**
+ * Exception thrown when applying a patch fails due to an invalid format
+ * 
+ * @since 2.0
+ * 
+ */
+public class PatchFormatException extends GitAPIException {
+	private static final long serialVersionUID = 1L;
+
+	private List<FormatError> errors;
+
+	/**
+	 * @param errors
+	 */
+	public PatchFormatException(List<FormatError> errors) {
+		super(MessageFormat.format(JGitText.get().patchFormatException, errors));
+		this.errors = errors;
+	}
+
+	/**
+	 * @return all the errors where unresolved conflicts have been detected
+	 */
+	public List<FormatError> getErrors() {
+		return errors;
+	}
+
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawText.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawText.java
index fa9ca84785..ddb00d1a47 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawText.java
@@ -280,6 +280,7 @@ public class RawText extends Sequence {
 	/**
 	 * Get the line delimiter for the first line.
 	 *
+	 * @since 2.0
 	 * @return the line delimiter or <code>null</code>
 	 */
 	public String getLineDelimiter() {
@@ -293,4 +294,23 @@ public class RawText extends Sequence {
 		else
 			return "\n";
 	}
+
+	/**
+	 * Get the EOL chars for the first line.
+	 *
+	 * @since 2.0
+	 * @return the EOL chars or <code>null</code>
+	 */
+	public String getEOL() {
+		int e = getEnd(0);
+		if (content.length > 1 && content[e - 2] == '\r'
+				&& content[e - 1] == '\n')
+			return "\r\n";
+		if (content.length > 0 && content[e - 1] == '\n')
+			return "\n";
+		if (content.length > 0 && content[e - 1] == '\r')
+			return "\r";
+		return null;
+	}
+
 }