1 /*
2 * Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de> and others
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Distribution License v. 1.0 which is available at
6 * https://www.eclipse.org/org/documents/edl-v10.php.
7 *
8 * SPDX-License-Identifier: BSD-3-Clause
9 */
10
11 package org.eclipse.jgit.diff;
12
13 /**
14 * A modified region detected between two versions of roughly the same content.
15 * <p>
16 * An edit covers the modified region only. It does not cover a common region.
17 * <p>
18 * Regions should be specified using 0 based notation, so add 1 to the start and
19 * end marks for line numbers in a file.
20 * <p>
21 * An edit where {@code beginA == endA && beginB < endB} is an insert edit, that
22 * is sequence B inserted the elements in region <code>[beginB, endB)</code> at
23 * <code>beginA</code>.
24 * <p>
25 * An edit where {@code beginA < endA && beginB == endB} is a delete edit, that
26 * is sequence B has removed the elements between <code>[beginA, endA)</code>.
27 * <p>
28 * An edit where {@code beginA < endA && beginB < endB} is a replace edit, that
29 * is sequence B has replaced the range of elements between
30 * <code>[beginA, endA)</code> with those found in <code>[beginB, endB)</code>.
31 */
32 public class Edit {
33 /** Type of edit */
34 public enum Type {
35 /** Sequence B has inserted the region. */
36 INSERT,
37
38 /** Sequence B has removed the region. */
39 DELETE,
40
41 /** Sequence B has replaced the region with different content. */
42 REPLACE,
43
44 /** Sequence A and B have zero length, describing nothing. */
45 EMPTY;
46 }
47
48 int beginA;
49
50 int endA;
51
52 int beginB;
53
54 int endB;
55
56 /**
57 * Create a new empty edit.
58 *
59 * @param as
60 * beginA: start and end of region in sequence A; 0 based.
61 * @param bs
62 * beginB: start and end of region in sequence B; 0 based.
63 */
64 public Edit(int as, int bs) {
65 this(as, as, bs, bs);
66 }
67
68 /**
69 * Create a new edit.
70 *
71 * @param as
72 * beginA: start of region in sequence A; 0 based.
73 * @param ae
74 * endA: end of region in sequence A; must be >= as.
75 * @param bs
76 * beginB: start of region in sequence B; 0 based.
77 * @param be
78 * endB: end of region in sequence B; must be > = bs.
79 */
80 public Edit(int as, int ae, int bs, int be) {
81 beginA = as;
82 endA = ae;
83
84 beginB = bs;
85 endB = be;
86 }
87
88 /**
89 * Get type
90 *
91 * @return the type of this region
92 */
93 public final Type getType() {
94 if (beginA < endA) {
95 if (beginB < endB) {
96 return Type.REPLACE;
97 }
98 return Type.DELETE;
99
100 }
101 if (beginB < endB) {
102 return Type.INSERT;
103 }
104 // beginB == endB)
105 return Type.EMPTY;
106 }
107
108 /**
109 * Whether edit is empty
110 *
111 * @return {@code true} if the edit is empty (lengths of both a and b is
112 * zero)
113 */
114 public final boolean isEmpty() {
115 return beginA == endA && beginB == endB;
116 }
117
118 /**
119 * Get start point in sequence A
120 *
121 * @return start point in sequence A
122 */
123 public final int getBeginA() {
124 return beginA;
125 }
126
127 /**
128 * Get end point in sequence A
129 *
130 * @return end point in sequence A
131 */
132 public final int getEndA() {
133 return endA;
134 }
135
136 /**
137 * Get start point in sequence B
138 *
139 * @return start point in sequence B
140 */
141 public final int getBeginB() {
142 return beginB;
143 }
144
145 /**
146 * Get end point in sequence B
147 *
148 * @return end point in sequence B
149 */
150 public final int getEndB() {
151 return endB;
152 }
153
154 /**
155 * Get length of the region in A
156 *
157 * @return length of the region in A
158 */
159 public final int getLengthA() {
160 return endA - beginA;
161 }
162
163 /**
164 * Get length of the region in B
165 *
166 * @return return length of the region in B
167 */
168 public final int getLengthB() {
169 return endB - beginB;
170 }
171
172 /**
173 * Move the edit region by the specified amount.
174 *
175 * @param amount
176 * the region is shifted by this amount, and can be positive or
177 * negative.
178 * @since 4.8
179 */
180 public final void shift(int amount) {
181 beginA += amount;
182 endA += amount;
183 beginB += amount;
184 endB += amount;
185 }
186
187 /**
188 * Construct a new edit representing the region before cut.
189 *
190 * @param cut
191 * the cut point. The beginning A and B points are used as the
192 * end points of the returned edit.
193 * @return an edit representing the slice of {@code this} edit that occurs
194 * before {@code cut} starts.
195 */
196 public final Editref="../../../../org/eclipse/jgit/diff/Edit.html#Edit">Edit before(Edit cut) {
197 return new Edit(beginA, cut.beginA, beginB, cut.beginB);
198 }
199
200 /**
201 * Construct a new edit representing the region after cut.
202 *
203 * @param cut
204 * the cut point. The ending A and B points are used as the
205 * starting points of the returned edit.
206 * @return an edit representing the slice of {@code this} edit that occurs
207 * after {@code cut} ends.
208 */
209 public final Edithref="../../../../org/eclipse/jgit/diff/Edit.html#Edit">Edit after(Edit cut) {
210 return new Edit(cut.endA, endA, cut.endB, endB);
211 }
212
213 /**
214 * Increase {@link #getEndA()} by 1.
215 */
216 public void extendA() {
217 endA++;
218 }
219
220 /**
221 * Increase {@link #getEndB()} by 1.
222 */
223 public void extendB() {
224 endB++;
225 }
226
227 /**
228 * Swap A and B, so the edit goes the other direction.
229 */
230 public void swap() {
231 final int sBegin = beginA;
232 final int sEnd = endA;
233
234 beginA = beginB;
235 endA = endB;
236
237 beginB = sBegin;
238 endB = sEnd;
239 }
240
241 /** {@inheritDoc} */
242 @Override
243 public int hashCode() {
244 return beginA ^ endA;
245 }
246
247 /** {@inheritDoc} */
248 @Override
249 public boolean equals(Object o) {
250 if (o instanceof Edit) {
251 final Edit href="../../../../org/eclipse/jgit/diff/Edit.html#Edit">Edit e = (Edit) o;
252 return this.beginA == e.beginA && this.endA == e.endA
253 && this.beginB == e.beginB && this.endB == e.endB;
254 }
255 return false;
256 }
257
258 /** {@inheritDoc} */
259 @SuppressWarnings("nls")
260 @Override
261 public String toString() {
262 final Type t = getType();
263 return t + "(" + beginA + "-" + endA + "," + beginB + "-" + endB + ")";
264 }
265 }