--- /dev/null
+/*
+ * Copyright (C) 2010, Google Inc.
+ * 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.diff;
+
+/**
+ * Compares two {@link Sequence}s to create an {@link EditList} of changes.
+ *
+ * An algorithm's {@code diff} method must be callable from concurrent threads
+ * without data collisions. This permits some algorithms to use a singleton
+ * pattern, with concurrent invocations using the same singleton. Other
+ * algorithms may support parameterization, in which case the caller can create
+ * a unique instance per thread.
+ */
+public interface DiffAlgorithm {
+ /**
+ * Compare two sequences and identify a list of edits between them.
+ *
+ * @param <S>
+ * type of sequence being compared.
+ * @param <C>
+ * type of comparator to evaluate the sequence elements.
+ * @param cmp
+ * the comparator supplying the element equivalence function.
+ * @param a
+ * the first (also known as old or pre-image) sequence. Edits
+ * returned by this algorithm will reference indexes using the
+ * 'A' side: {@link Edit#getBeginA()}, {@link Edit#getEndA()}.
+ * @param b
+ * the second (also known as new or post-image) sequence. Edits
+ * returned by this algorithm will reference indexes using the
+ * 'B' side: {@link Edit#getBeginB()}, {@link Edit#getEndB()}.
+ * @return a modifiable edit list comparing the two sequences. If empty, the
+ * sequences are identical according to {@code cmp}'s rules. The
+ * result list is never null.
+ */
+ public <S extends Sequence, C extends SequenceComparator<? super S>> EditList diff(
+ C cmp, S a, S b);
+}
private int abbreviationLength = 7;
+ private DiffAlgorithm diffAlgorithm = MyersDiff.INSTANCE;
+
private RawTextComparator comparator = RawTextComparator.DEFAULT;
private int binaryFileThreshold = DEFAULT_BINARY_FILE_THRESHOLD;
abbreviationLength = count;
}
+ /**
+ * Set the algorithm that constructs difference output.
+ *
+ * @param alg
+ * the algorithm to produce text file differences.
+ * @see MyersDiff#INSTANCE
+ */
+ public void setDiffAlgorithm(DiffAlgorithm alg) {
+ diffAlgorithm = alg;
+ }
+
/**
* Set the line equivalence function for text file differences.
*
}
private EditList diff(RawText a, RawText b) {
- return new MyersDiff<RawText>(comparator, a, b).getEdits();
+ return diffAlgorithm.diff(comparator, a, b);
}
private void assertHaveRepository() {
* type of sequence.
*/
public class MyersDiff<S extends Sequence> {
+ /** Singleton instance of MyersDiff. */
+ public static final DiffAlgorithm INSTANCE = new DiffAlgorithm() {
+ public <S extends Sequence, C extends SequenceComparator<? super S>> EditList diff(
+ C cmp, S a, S b) {
+ return new MyersDiff<S>(cmp, a, b).getEdits();
+ }
+ };
+
/**
* The list of edits found during the last call to {@link #calculateEdits()}
*/
protected EditList edits;
/** Comparison function for sequences. */
- protected SequenceComparator<S> cmp;
+ protected SequenceComparator<? super S> cmp;
/**
* The first text to be compared. Referred to as "Text A" in the comments
*/
protected S b;
- /**
- * The only constructor
- *
- * @param cmp comparison method for this execution.
- * @param a the text A which should be compared
- * @param b the text B which should be compared
- */
- public MyersDiff(SequenceComparator<S> cmp, S a, S b) {
+ private MyersDiff(SequenceComparator<? super S> cmp, S a, S b) {
this.cmp = cmp;
this.a = a;
this.b = b;
projects / jgit.git / commitdiff