1 /*
2 * Copyright (C) 2010, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.diff;
45
46 /**
47 * Compares two sequences primarily based upon hash codes.
48 */
49 public abstract class LowLevelDiffAlgorithm extends DiffAlgorithm {
50 /** {@inheritDoc} */
51 @Override
52 public <S extends Sequence> EditList diffNonCommon(
53 SequenceComparator<? super S> cmp, S a, S b) {
54 HashedSequencePair<S> p = new HashedSequencePair<>(cmp, a, b);
55 HashedSequenceComparator<S> hc = p.getComparator();
56 HashedSequence<S> ha = p.getA();
57 HashedSequence<S> hb = p.getB();
58 p = null;
59
60 EditList res = new EditList();
61 Edit region = new Edit(0, a.size(), 0, b.size());
62 diffNonCommon(res, hc, ha, hb, region);
63 return res;
64 }
65
66 /**
67 * Compare two sequences and identify a list of edits between them.
68 *
69 * This method should be invoked only after the two sequences have been
70 * proven to have no common starting or ending elements. The expected
71 * elimination of common starting and ending elements is automatically
72 * performed by the {@link #diff(SequenceComparator, Sequence, Sequence)}
73 * method, which invokes this method using
74 * {@link org.eclipse.jgit.diff.Subsequence}s.
75 *
76 * @param edits
77 * result list to append the region's edits onto.
78 * @param cmp
79 * the comparator supplying the element equivalence function.
80 * @param a
81 * the first (also known as old or pre-image) sequence. Edits
82 * returned by this algorithm will reference indexes using the
83 * 'A' side: {@link org.eclipse.jgit.diff.Edit#getBeginA()},
84 * {@link org.eclipse.jgit.diff.Edit#getEndA()}.
85 * @param b
86 * the second (also known as new or post-image) sequence. Edits
87 * returned by this algorithm will reference indexes using the
88 * 'B' side: {@link org.eclipse.jgit.diff.Edit#getBeginB()},
89 * {@link org.eclipse.jgit.diff.Edit#getEndB()}.
90 * @param region
91 * the region being compared within the two sequences.
92 */
93 public abstract <S extends Sequence> void diffNonCommon(EditList edits,
94 HashedSequenceComparator<S> cmp, HashedSequence<S> a,
95 HashedSequence<S> b, Edit region);
96 }