/*
 * Copyright (C) 2009, 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
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 *
 * - 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.
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package org.eclipse.jgit.merge;

import java.util.Iterator;
import java.util.List;

import org.eclipse.jgit.diff.Sequence;
import org.eclipse.jgit.merge.MergeChunk.ConflictState;
import org.eclipse.jgit.util.IntList;

The result of merging a number of Sequence objects. These sequences have one common predecessor sequence. The result of a merge is a list of MergeChunks. Each MergeChunk contains either a range (a subsequence) from one of the merged sequences, a range from the common predecessor or a conflicting range from one of the merged sequences. A conflict will be reported as multiple chunks, one for each conflicting range. The first chunk for a conflict is marked specially to distinguish the border between two consecutive conflicts. 

This class does not know anything about how to present the merge result to
the end-user. MergeFormatters have to be used to construct something human
readable.
Type parameters:
<S> – 
           type of sequence./**
 * The result of merging a number of {@link org.eclipse.jgit.diff.Sequence}
 * objects. These sequences have one common predecessor sequence. The result of
 * a merge is a list of MergeChunks. Each MergeChunk contains either a range (a
 * subsequence) from one of the merged sequences, a range from the common
 * predecessor or a conflicting range from one of the merged sequences. A
 * conflict will be reported as multiple chunks, one for each conflicting range.
 * The first chunk for a conflict is marked specially to distinguish the border
 * between two consecutive conflicts.
 * <p>
 * This class does not know anything about how to present the merge result to
 * the end-user. MergeFormatters have to be used to construct something human
 * readable.
 *
 * @param <S>
 *            type of sequence.
 */
public class MergeResult<S extends Sequence> implements Iterable<MergeChunk> {
	private final List<S> sequences;

	final IntList chunks = new IntList();

	private boolean containsConflicts = false;

	
Creates a new empty MergeResult
Params:
sequences –  contains the common predecessor sequence at position 0 followed by the merged sequences. This list should not be modified anymore during the lifetime of this MergeResult./**
	 * Creates a new empty MergeResult
	 *
	 * @param sequences
	 *            contains the common predecessor sequence at position 0
	 *            followed by the merged sequences. This list should not be
	 *            modified anymore during the lifetime of this
	 *            {@link org.eclipse.jgit.merge.MergeResult}.
	 */
	public MergeResult(List<S> sequences) {
		this.sequences = sequences;
	}

	
Adds a new range from one of the merged sequences or from the common
predecessor. This method can add conflicting and non-conflicting ranges
controlled by the conflictState parameter
Params:
srcIdx – 
           determines from which sequence this range comes. An index of
           x specifies the x+1 element in the list of sequences
           specified to the constructor
begin – 
           the first element from the specified sequence which should be
           included in the merge result. Indexes start with 0.
end – 
           specifies the end of the range to be added. The element this
           index points to is the first element which not added to the
           merge result. All elements between begin (including begin) and
           this element are added.
conflictState – 
           when set to NO_CONLICT a non-conflicting range is added.
           This will end implicitly all open conflicts added before./**
	 * Adds a new range from one of the merged sequences or from the common
	 * predecessor. This method can add conflicting and non-conflicting ranges
	 * controlled by the conflictState parameter
	 *
	 * @param srcIdx
	 *            determines from which sequence this range comes. An index of
	 *            x specifies the x+1 element in the list of sequences
	 *            specified to the constructor
	 * @param begin
	 *            the first element from the specified sequence which should be
	 *            included in the merge result. Indexes start with 0.
	 * @param end
	 *            specifies the end of the range to be added. The element this
	 *            index points to is the first element which not added to the
	 *            merge result. All elements between begin (including begin) and
	 *            this element are added.
	 * @param conflictState
	 *            when set to NO_CONLICT a non-conflicting range is added.
	 *            This will end implicitly all open conflicts added before.
	 */
	public void add(int srcIdx, int begin, int end, ConflictState conflictState) {
		chunks.add(conflictState.ordinal());
		chunks.add(srcIdx);
		chunks.add(begin);
		chunks.add(end);
		if (conflictState != ConflictState.NO_CONFLICT)
			containsConflicts = true;
	}

	
Returns the common predecessor sequence and the merged sequence in one
list. The common predecessor is the first element in the list
Returns:
the common predecessor at position 0 followed by the merged
        sequences./**
	 * Returns the common predecessor sequence and the merged sequence in one
	 * list. The common predecessor is the first element in the list
	 *
	 * @return the common predecessor at position 0 followed by the merged
	 *         sequences.
	 */
	public List<S> getSequences() {
		return sequences;
	}

	static final ConflictState[] states = ConflictState.values();

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public Iterator<MergeChunk> iterator() {
		return new Iterator<MergeChunk>() {
			int idx;

			@Override
			public boolean hasNext() {
				return (idx < chunks.size());
			}

			@Override
			public MergeChunk next() {
				ConflictState state = states[chunks.get(idx++)];
				int srcIdx = chunks.get(idx++);
				int begin = chunks.get(idx++);
				int end = chunks.get(idx++);
				return new MergeChunk(srcIdx, begin, end, state);
			}

			@Override
			public void remove() {
				throw new UnsupportedOperationException();
			}
		};
	}

	
Whether this merge result contains conflicts
Returns:
true if this merge result contains conflicts/**
	 * Whether this merge result contains conflicts
	 *
	 * @return true if this merge result contains conflicts
	 */
	public boolean containsConflicts() {
		return containsConflicts;
	}

	
Sets explicitly whether this merge should be seen as containing a
conflict or not. Needed because during RecursiveMerger we want to do
content-merges and take the resulting content (even with conflict
markers!) as new conflict-free content
Params:
containsConflicts – 
           whether this merge should be seen as containing a conflict or
           not.
Since:
3.5/**
	 * Sets explicitly whether this merge should be seen as containing a
	 * conflict or not. Needed because during RecursiveMerger we want to do
	 * content-merges and take the resulting content (even with conflict
	 * markers!) as new conflict-free content
	 *
	 * @param containsConflicts
	 *            whether this merge should be seen as containing a conflict or
	 *            not.
	 * @since 3.5
	 */
	protected void setContainsConflicts(boolean containsConflicts) {
		this.containsConflicts = containsConflicts;
	}
}