Enable to prepare interactive rebase and then start it explicitly

Add Operation.PROCESS_STEPS to RebaseCommand to enable starting
interactive rebase explicitly after rebase steps have been configured.

Change-Id: I2d6f0de82010ea6523fbce6fb4501e847bdcdddc
Signed-off-by: Tobias Pfeifer <to.pfeifer@web.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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

 		/**
 		 * Aborts and resets the current rebase
 		 */
-		ABORT;
+		ABORT,
+		/**
+		 * Starts processing steps
+		 */
+		PROCESS_STEPS;
 	}
 
 	private Operation operation = Operation.BEGIN;
 
 	private InteractiveHandler interactiveHandler;
 
+	private boolean stopAfterInitialization = false;
+
 	/**
 	 * @param repo
 	 */
 				} catch (IOException ioe) {
 					throw new JGitInternalException(ioe.getMessage(), ioe);
 				}
+			case PROCESS_STEPS:
+				// fall through
 			case SKIP:
 				// fall through
 			case CONTINUE:
 				break;
 			case BEGIN:
 				RebaseResult res = initFilesAndRewind();
+				if (stopAfterInitialization)
+					return RebaseResult.INTERACTIVE_PREPARED_RESULT;
 				if (res != null)
 					return res;
 			}
 	}
 
 	private void checkParameters() throws WrongRepositoryStateException {
+		if (this.operation == Operation.PROCESS_STEPS) {
+			if (rebaseState.getFile(DONE).exists())
+				throw new WrongRepositoryStateException(MessageFormat.format(
+						JGitText.get().wrongRepositoryState, repo
+								.getRepositoryState().name()));
+		}
 		if (this.operation != Operation.BEGIN) {
 			// these operations are only possible while in a rebasing state
 			switch (repo.getRepositoryState()) {
 
 	/**
 	 * Enables interactive rebase
+	 * <p>
+	 * Does not stop after initialization of interactive rebase. This is
+	 * equivalent to
+	 * {@link RebaseCommand#runInteractively(InteractiveHandler, boolean)
+	 * runInteractively(handler, false)};
+	 * </p>
 	 *
 	 * @param handler
 	 * @return this
 	 */
 	public RebaseCommand runInteractively(InteractiveHandler handler) {
+		return runInteractively(handler, false);
+	}
+
+	/**
+	 * Enables interactive rebase
+	 * <p>
+	 * If stopAfterRebaseInteractiveInitialization is {@code true} the rebase
+	 * stops after initialization of interactive rebase returning
+	 * {@link RebaseResult#INTERACTIVE_PREPARED_RESULT}
+	 * </p>
+	 *
+	 * @param handler
+	 * @param stopAfterRebaseInteractiveInitialization
+	 *            if {@code true} the rebase stops after initialization
+	 * @return this instance
+	 */
+	public RebaseCommand runInteractively(InteractiveHandler handler,
+			final boolean stopAfterRebaseInteractiveInitialization) {
+		this.stopAfterInitialization = stopAfterRebaseInteractiveInitialization;
 		this.interactiveHandler = handler;
 		return this;
 	}

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

 /*
- * Copyright (C) 2010, Mathias Kinzler <mathias.kinzler@sap.com>
+ * Copyright (C) 2010, 2013, Mathias Kinzler <mathias.kinzler@sap.com>
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
 			public boolean isSuccessful() {
 				return false;
 			}
+		},
+
+		/**
+		 * Interactive rebase has been prepared
+		 */
+		INTERACTIVE_PREPARED {
+			@Override
+			public boolean isSuccessful() {
+				return false;
+			}
 		};
 
 		/**
 	static final RebaseResult NOTHING_TO_COMMIT_RESULT = new RebaseResult(
 			Status.NOTHING_TO_COMMIT);
 
+	static final RebaseResult INTERACTIVE_PREPARED_RESULT =  new RebaseResult(
+			Status.INTERACTIVE_PREPARED);
+
 	private final Status status;
 
 	private final RevCommit currentCommit;