4e919bc83c00327b18bee6a3958733d38b820637
[lhc/web/wiklou.git] / includes / diff / DairikiDiff.php
1 <?php
2 /**
3 * A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
4 *
5 * Copyright © 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
6 * You may copy this code freely under the conditions of the GPL.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
21 * http://www.gnu.org/copyleft/gpl.html
22 *
23 * @file
24 * @ingroup DifferenceEngine
25 * @defgroup DifferenceEngine DifferenceEngine
26 */
27
28 /**
29 * The base class for all other DiffOp classes.
30 *
31 * The classes that extend DiffOp are: DiffOpCopy, DiffOpDelete, DiffOpAdd and
32 * DiffOpChange. FakeDiffOp also extends DiffOp, but it is not located in this file.
33 *
34 * @private
35 * @ingroup DifferenceEngine
36 */
37 abstract class DiffOp {
38
39 /**
40 * @var string
41 */
42 public $type;
43
44 /**
45 * @var string[]
46 */
47 public $orig;
48
49 /**
50 * @var string[]
51 */
52 public $closing;
53
54 /**
55 * @return string
56 */
57 public function getType() {
58 return $this->type;
59 }
60
61 /**
62 * @return string[]
63 */
64 public function getOrig() {
65 return $this->orig;
66 }
67
68 /**
69 * @param int|null $i
70 * @return string[]|string|null
71 */
72 public function getClosing( $i = null ) {
73 if ( $i === null ) {
74 return $this->closing;
75 }
76 if ( array_key_exists( $i, $this->closing ) ) {
77 return $this->closing[$i];
78 }
79 return null;
80 }
81
82 abstract public function reverse();
83
84 /**
85 * @return int
86 */
87 public function norig() {
88 return $this->orig ? count( $this->orig ) : 0;
89 }
90
91 /**
92 * @return int
93 */
94 public function nclosing() {
95 return $this->closing ? count( $this->closing ) : 0;
96 }
97 }
98
99 /**
100 * Extends DiffOp. Used to mark strings that have been
101 * copied from one string array to the other.
102 *
103 * @private
104 * @ingroup DifferenceEngine
105 */
106 class DiffOpCopy extends DiffOp {
107 public $type = 'copy';
108
109 public function __construct( $orig, $closing = false ) {
110 if ( !is_array( $closing ) ) {
111 $closing = $orig;
112 }
113 $this->orig = $orig;
114 $this->closing = $closing;
115 }
116
117 /**
118 * @return DiffOpCopy
119 */
120 public function reverse() {
121 return new DiffOpCopy( $this->closing, $this->orig );
122 }
123 }
124
125 /**
126 * Extends DiffOp. Used to mark strings that have been
127 * deleted from the first string array.
128 *
129 * @private
130 * @ingroup DifferenceEngine
131 */
132 class DiffOpDelete extends DiffOp {
133 public $type = 'delete';
134
135 public function __construct( $lines ) {
136 $this->orig = $lines;
137 $this->closing = false;
138 }
139
140 /**
141 * @return DiffOpAdd
142 */
143 public function reverse() {
144 return new DiffOpAdd( $this->orig );
145 }
146 }
147
148 /**
149 * Extends DiffOp. Used to mark strings that have been
150 * added from the first string array.
151 *
152 * @private
153 * @ingroup DifferenceEngine
154 */
155 class DiffOpAdd extends DiffOp {
156 public $type = 'add';
157
158 public function __construct( $lines ) {
159 $this->closing = $lines;
160 $this->orig = false;
161 }
162
163 /**
164 * @return DiffOpDelete
165 */
166 public function reverse() {
167 return new DiffOpDelete( $this->closing );
168 }
169 }
170
171 /**
172 * Extends DiffOp. Used to mark strings that have been
173 * changed from the first string array (both added and subtracted).
174 *
175 * @private
176 * @ingroup DifferenceEngine
177 */
178 class DiffOpChange extends DiffOp {
179 public $type = 'change';
180
181 public function __construct( $orig, $closing ) {
182 $this->orig = $orig;
183 $this->closing = $closing;
184 }
185
186 /**
187 * @return DiffOpChange
188 */
189 public function reverse() {
190 return new DiffOpChange( $this->closing, $this->orig );
191 }
192 }
193
194 /**
195 * Class representing a 'diff' between two sequences of strings.
196 * @todo document
197 * @private
198 * @ingroup DifferenceEngine
199 */
200 class Diff {
201
202 /**
203 * @var DiffOp[]
204 */
205 public $edits;
206
207 /**
208 * @var int If this diff complexity is exceeded, a ComplexityException is thrown
209 * 0 means no limit.
210 */
211 protected $bailoutComplexity = 0;
212
213 /**
214 * Computes diff between sequences of strings.
215 *
216 * @param string[] $from_lines An array of strings.
217 * Typically these are lines from a file.
218 * @param string[] $to_lines An array of strings.
219 * @throws \MediaWiki\Diff\ComplexityException
220 */
221 public function __construct( $from_lines, $to_lines ) {
222 $eng = new DiffEngine;
223 $eng->setBailoutComplexity( $this->bailoutComplexity );
224 $this->edits = $eng->diff( $from_lines, $to_lines );
225 }
226
227 /**
228 * @return DiffOp[]
229 */
230 public function getEdits() {
231 return $this->edits;
232 }
233
234 /**
235 * Compute reversed Diff.
236 *
237 * SYNOPSIS:
238 *
239 * $diff = new Diff($lines1, $lines2);
240 * $rev = $diff->reverse();
241 *
242 * @return Object A Diff object representing the inverse of the
243 * original diff.
244 */
245 public function reverse() {
246 $rev = $this;
247 $rev->edits = [];
248 /** @var DiffOp $edit */
249 foreach ( $this->edits as $edit ) {
250 $rev->edits[] = $edit->reverse();
251 }
252
253 return $rev;
254 }
255
256 /**
257 * Check for empty diff.
258 *
259 * @return bool True if two sequences were identical.
260 */
261 public function isEmpty() {
262 foreach ( $this->edits as $edit ) {
263 if ( $edit->type != 'copy' ) {
264 return false;
265 }
266 }
267
268 return true;
269 }
270
271 /**
272 * Compute the length of the Longest Common Subsequence (LCS).
273 *
274 * This is mostly for diagnostic purposed.
275 *
276 * @return int The length of the LCS.
277 */
278 public function lcs() {
279 $lcs = 0;
280 foreach ( $this->edits as $edit ) {
281 if ( $edit->type == 'copy' ) {
282 $lcs += count( $edit->orig );
283 }
284 }
285
286 return $lcs;
287 }
288
289 /**
290 * Get the original set of lines.
291 *
292 * This reconstructs the $from_lines parameter passed to the
293 * constructor.
294 *
295 * @return string[] The original sequence of strings.
296 */
297 public function orig() {
298 $lines = [];
299
300 foreach ( $this->edits as $edit ) {
301 if ( $edit->orig ) {
302 array_splice( $lines, count( $lines ), 0, $edit->orig );
303 }
304 }
305
306 return $lines;
307 }
308
309 /**
310 * Get the closing set of lines.
311 *
312 * This reconstructs the $to_lines parameter passed to the
313 * constructor.
314 *
315 * @return string[] The sequence of strings.
316 */
317 public function closing() {
318 $lines = [];
319
320 foreach ( $this->edits as $edit ) {
321 if ( $edit->closing ) {
322 array_splice( $lines, count( $lines ), 0, $edit->closing );
323 }
324 }
325
326 return $lines;
327 }
328 }