Enhance reading of git-rebase-todo formatted files

Reading and writing files formatted like the git-rebase-todo files was
hidden in the RebaseCommand. Certain constructs (like leading tabs and
spaces) have not been handled as in native git. Also the upcoming
rebase interactive feature in EGit needs reading/writing these files
independently from a RebaseCommand.

Therefore reading and writing those files has been moved to the
Repository class. RebaseCommand gets smaller because of that and doesn't
have to deal with reading/writing files.

Additional tests for empty todo-list files, or files containing comments
have been added.

Change-Id: I323f3619952fecdf28ddf50139a88e0bea34f5ba
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Also-by: Tobias Pfeifer <to.pfeifer@sap.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/RebaseTodoFile.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/RebaseTodoFile.java
new file mode 100644
index 0000000000..a386fff0e1
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/RebaseTodoFile.java
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2013, Christian Halstrick <christian.halstrick@sap.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.lib;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.eclipse.jgit.util.IO;
+import org.eclipse.jgit.util.RawParseUtils;
+
+/**
+ * Offers methods to read and write files formatted like the git-rebase-todo
+ * file
+ */
+public class RebaseTodoFile {
+	private Repository repo;
+
+	/**
+	 * @param repo
+	 */
+	public RebaseTodoFile(Repository repo) {
+		this.repo = repo;
+	}
+
+	/**
+	 * Read a file formatted like the git-rebase-todo file. The "done" file is
+	 * also formatted like the git-rebase-todo file. These files can be found in
+	 * .git/rebase-merge/ or .git/rebase-append/ folders.
+	 *
+	 * @param path
+	 *            path to the file relative to the repository's git-dir. E.g.
+	 *            "rebase-merge/git-rebase-todo" or "rebase-append/done"
+	 * @param includeComments
+	 *            <code>true</code> if also comments should be reported
+	 * @return the list of steps
+	 * @throws IOException
+	 */
+	public List<RebaseTodoLine> readRebaseTodo(String path,
+			boolean includeComments) throws IOException {
+		byte[] buf = IO.readFully(new File(repo.getDirectory(), path));
+		int ptr = 0;
+		int tokenBegin = 0;
+		List<RebaseTodoLine> r = new LinkedList<RebaseTodoLine>();
+		while (ptr < buf.length) {
+			RebaseTodoLine.Action action = null;
+			AbbreviatedObjectId commit = null;
+			tokenBegin = ptr;
+			ptr = RawParseUtils.nextLF(buf, ptr);
+			int lineStart = tokenBegin;
+			int lineEnd = ptr - 2;
+			if (lineEnd >= 0 && buf[lineEnd] == '\r')
+				lineEnd--;
+			// Handle comments
+			if (buf[tokenBegin] == '#') {
+				if (includeComments)
+					r.add(new RebaseTodoLine(RawParseUtils.decode(buf,
+							tokenBegin, lineEnd + 1)));
+				continue;
+			}
+			// skip leading spaces, tabs, CR
+			while (tokenBegin <= lineEnd
+					&& (buf[tokenBegin] == ' ' || buf[tokenBegin] == '\t' || buf[tokenBegin] == '\r'))
+				tokenBegin++;
+			// Handle empty lines (maybe empty after skipping leading
+			// whitespace)
+			if (tokenBegin > lineEnd) {
+				if (includeComments)
+					r.add(new RebaseTodoLine(RawParseUtils.decode(buf,
+							lineStart, 1 + lineEnd)));
+				continue;
+			}
+			int nextSpace = RawParseUtils.next(buf, tokenBegin, ' ');
+			int tokenCount = 0;
+			while (tokenCount < 3 && nextSpace < ptr) {
+				switch (tokenCount) {
+				case 0:
+					String actionToken = new String(buf, tokenBegin, nextSpace
+							- tokenBegin - 1);
+					tokenBegin = nextSpace;
+					action = RebaseTodoLine.Action.parse(actionToken);
+					break;
+				case 1:
+					if (action == null)
+						break;
+					nextSpace = RawParseUtils.next(buf, tokenBegin, ' ');
+					String commitToken = new String(buf, tokenBegin, nextSpace
+							- tokenBegin - 1);
+					tokenBegin = nextSpace;
+					commit = AbbreviatedObjectId.fromString(commitToken);
+					break;
+				case 2:
+					if (action == null)
+						break;
+					r.add(new RebaseTodoLine(action, commit, RawParseUtils
+							.decode(buf, tokenBegin, 1 + lineEnd)));
+					break;
+				}
+				tokenCount++;
+			}
+		}
+		return r;
+	}
+
+	/**
+	 * Write a file formatted like a git-rebase-todo file.
+	 *
+	 * @param path
+	 *            path to the file relative to the repository's git-dir. E.g.
+	 *            "rebase-merge/git-rebase-todo" or "rebase-append/done"
+	 * @param steps
+	 *            the steps to be written
+	 * @param append
+	 *            whether to append to an existing file or to write a new file
+	 * @throws IOException
+	 */
+	public void writeRebaseTodoFile(String path, List<RebaseTodoLine> steps,
+			boolean append) throws IOException {
+		BufferedWriter fw = new BufferedWriter(new OutputStreamWriter(
+				new FileOutputStream(new File(repo.getDirectory(), path),
+						append), Constants.CHARACTER_ENCODING));
+		try {
+			StringBuilder sb = new StringBuilder();
+			for (RebaseTodoLine step : steps) {
+				sb.setLength(0);
+				if (RebaseTodoLine.Action.COMMENT.equals(step.action))
+					sb.append(step.getComment());
+				else {
+					sb.append(step.getAction().toToken());
+					sb.append(" "); //$NON-NLS-1$
+					sb.append(step.getCommit().name());
+					sb.append(" "); //$NON-NLS-1$
+					sb.append(step.getShortMessage().trim());
+				}
+				fw.write(sb.toString());
+				fw.newLine();
+			}
+		} finally {
+			fw.close();
+		}
+	}
+}