summaryrefslogtreecommitdiff
path: root/includes/content/Content.php
blob: 72729b09b806aa9149194528388529e0250d74bf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
<?php
/**
 * A content object represents page content, e.g. the text to show on a page.
 * Content objects have no knowledge about how they relate to wiki pages.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @since 1.21
 *
 * @file
 * @ingroup Content
 *
 * @author Daniel Kinzler
 */

/**
 * Base interface for content objects.
 *
 * @ingroup Content
 */
interface Content {

	/**
	 * @since 1.21
	 *
	 * @return string A string representing the content in a way useful for
	 *   building a full text search index. If no useful representation exists,
	 *   this method returns an empty string.
	 *
	 * @todo: test that this actually works
	 * @todo: make sure this also works with LuceneSearch / WikiSearch
	 */
	public function getTextForSearchIndex();

	/**
	 * @since 1.21
	 *
	 * @return string|false The wikitext to include when another page includes this
	 * content, or false if the content is not includable in a wikitext page.
	 *
	 * @todo allow native handling, bypassing wikitext representation, like
	 *    for includable special pages.
	 * @todo allow transclusion into other content models than Wikitext!
	 * @todo used in WikiPage and MessageCache to get message text. Not so
	 *    nice. What should we use instead?!
	 */
	public function getWikitextForTransclusion();

	/**
	 * Returns a textual representation of the content suitable for use in edit
	 * summaries and log messages.
	 *
	 * @since 1.21
	 *
	 * @param int $maxLength Maximum length of the summary text
	 * @return string The summary text
	 */
	public function getTextForSummary( $maxLength = 250 );

	/**
	 * Returns native representation of the data. Interpretation depends on
	 * the data model used, as given by getDataModel().
	 *
	 * @since 1.21
	 *
	 * @return mixed The native representation of the content. Could be a
	 *    string, a nested array structure, an object, a binary blob...
	 *    anything, really.
	 *
	 * @note Caller must be aware of content model!
	 */
	public function getNativeData();

	/**
	 * Returns the content's nominal size in bogo-bytes.
	 *
	 * @return int
	 */
	public function getSize();

	/**
	 * Returns the ID of the content model used by this Content object.
	 * Corresponds to the CONTENT_MODEL_XXX constants.
	 *
	 * @since 1.21
	 *
	 * @return String The model id
	 */
	public function getModel();

	/**
	 * Convenience method that returns the ContentHandler singleton for handling
	 * the content model that this Content object uses.
	 *
	 * Shorthand for ContentHandler::getForContent( $this )
	 *
	 * @since 1.21
	 *
	 * @return ContentHandler
	 */
	public function getContentHandler();

	/**
	 * Convenience method that returns the default serialization format for the
	 * content model that this Content object uses.
	 *
	 * Shorthand for $this->getContentHandler()->getDefaultFormat()
	 *
	 * @since 1.21
	 *
	 * @return String
	 */
	public function getDefaultFormat();

	/**
	 * Convenience method that returns the list of serialization formats
	 * supported for the content model that this Content object uses.
	 *
	 * Shorthand for $this->getContentHandler()->getSupportedFormats()
	 *
	 * @since 1.21
	 *
	 * @return Array of supported serialization formats
	 */
	public function getSupportedFormats();

	/**
	 * Returns true if $format is a supported serialization format for this
	 * Content object, false if it isn't.
	 *
	 * Note that this should always return true if $format is null, because null
	 * stands for the default serialization.
	 *
	 * Shorthand for $this->getContentHandler()->isSupportedFormat( $format )
	 *
	 * @since 1.21
	 *
	 * @param string $format The format to check
	 * @return bool Whether the format is supported
	 */
	public function isSupportedFormat( $format );

	/**
	 * Convenience method for serializing this Content object.
	 *
	 * Shorthand for $this->getContentHandler()->serializeContent( $this, $format )
	 *
	 * @since 1.21
	 *
	 * @param $format null|string The desired serialization format (or null for
	 *    the default format).
	 * @return string Serialized form of this Content object
	 */
	public function serialize( $format = null );

	/**
	 * Returns true if this Content object represents empty content.
	 *
	 * @since 1.21
	 *
	 * @return bool Whether this Content object is empty
	 */
	public function isEmpty();

	/**
	 * Returns whether the content is valid. This is intended for local validity
	 * checks, not considering global consistency.
	 *
	 * Content needs to be valid before it can be saved.
	 *
	 * This default implementation always returns true.
	 *
	 * @since 1.21
	 *
	 * @return boolean
	 */
	public function isValid();

	/**
	 * Returns true if this Content objects is conceptually equivalent to the
	 * given Content object.
	 *
	 * Contract:
	 *
	 * - Will return false if $that is null.
	 * - Will return true if $that === $this.
	 * - Will return false if $that->getModel() != $this->getModel().
	 * - Will return false if $that->getNativeData() is not equal to $this->getNativeData(),
	 *   where the meaning of "equal" depends on the actual data model.
	 *
	 * Implementations should be careful to make equals() transitive and reflexive:
	 *
	 * - $a->equals( $b ) <=> $b->equals( $a )
	 * - $a->equals( $b ) &&  $b->equals( $c ) ==> $a->equals( $c )
	 *
	 * @since 1.21
	 *
	 * @param $that Content The Content object to compare to
	 * @return bool True if this Content object is equal to $that, false otherwise.
	 */
	public function equals( Content $that = null );

	/**
	 * Return a copy of this Content object. The following must be true for the
	 * object returned:
	 *
	 * if $copy = $original->copy()
	 *
	 * - get_class($original) === get_class($copy)
	 * - $original->getModel() === $copy->getModel()
	 * - $original->equals( $copy )
	 *
	 * If and only if the Content object is immutable, the copy() method can and
	 * should return $this. That is, $copy === $original may be true, but only
	 * for immutable content objects.
	 *
	 * @since 1.21
	 *
	 * @return Content. A copy of this object
	 */
	public function copy();

	/**
	 * Returns true if this content is countable as a "real" wiki page, provided
	 * that it's also in a countable location (e.g. a current revision in the
	 * main namespace).
	 *
	 * @since 1.21
	 *
	 * @param bool $hasLinks If it is known whether this content contains
	 *    links, provide this information here, to avoid redundant parsing to
	 *    find out.
	 * @return boolean
	 */
	public function isCountable( $hasLinks = null );

	/**
	 * Parse the Content object and generate a ParserOutput from the result.
	 * $result->getText() can be used to obtain the generated HTML. If no HTML
	 * is needed, $generateHtml can be set to false; in that case,
	 * $result->getText() may return null.
	 *
	 * @param $title Title The page title to use as a context for rendering
	 * @param $revId null|int The revision being rendered (optional)
	 * @param $options null|ParserOptions Any parser options
	 * @param $generateHtml Boolean Whether to generate HTML (default: true). If false,
	 *        the result of calling getText() on the ParserOutput object returned by
	 *        this method is undefined.
	 *
	 * @since 1.21
	 *
	 * @return ParserOutput
	 */
	public function getParserOutput( Title $title,
		$revId = null,
		ParserOptions $options = null, $generateHtml = true );
	// TODO: make RenderOutput and RenderOptions base classes

	/**
	 * Returns a list of DataUpdate objects for recording information about this
	 * Content in some secondary data store. If the optional second argument,
	 * $old, is given, the updates may model only the changes that need to be
	 * made to replace information about the old content with information about
	 * the new content.
	 *
	 * This default implementation calls
	 * $this->getParserOutput( $content, $title, null, null, false ),
	 * and then calls getSecondaryDataUpdates( $title, $recursive ) on the
	 * resulting ParserOutput object.
	 *
	 * Subclasses may implement this to determine the necessary updates more
	 * efficiently, or make use of information about the old content.
	 *
	 * @param $title Title The context for determining the necessary updates
	 * @param $old Content|null An optional Content object representing the
	 *    previous content, i.e. the content being replaced by this Content
	 *    object.
	 * @param $recursive boolean Whether to include recursive updates (default:
	 *    false).
	 * @param $parserOutput ParserOutput|null Optional ParserOutput object.
	 *    Provide if you have one handy, to avoid re-parsing of the content.
	 *
	 * @return Array. A list of DataUpdate objects for putting information
	 *    about this content object somewhere.
	 *
	 * @since 1.21
	 */
	public function getSecondaryDataUpdates( Title $title,
		Content $old = null,
		$recursive = true, ParserOutput $parserOutput = null
	);

	/**
	 * Construct the redirect destination from this content and return an
	 * array of Titles, or null if this content doesn't represent a redirect.
	 * The last element in the array is the final destination after all redirects
	 * have been resolved (up to $wgMaxRedirects times).
	 *
	 * @since 1.21
	 *
	 * @return Array of Titles, with the destination last
	 */
	public function getRedirectChain();

	/**
	 * Construct the redirect destination from this content and return a Title,
	 * or null if this content doesn't represent a redirect.
	 * This will only return the immediate redirect target, useful for
	 * the redirect table and other checks that don't need full recursion.
	 *
	 * @since 1.21
	 *
	 * @return Title: The corresponding Title
	 */
	public function getRedirectTarget();

	/**
	 * Construct the redirect destination from this content and return the
	 * Title, or null if this content doesn't represent a redirect.
	 *
	 * This will recurse down $wgMaxRedirects times or until a non-redirect
	 * target is hit in order to provide (hopefully) the Title of the final
	 * destination instead of another redirect.
	 *
	 * There is usually no need to override the default behavior, subclasses that
	 * want to implement redirects should override getRedirectTarget().
	 *
	 * @since 1.21
	 *
	 * @return Title
	 */
	public function getUltimateRedirectTarget();

	/**
	 * Returns whether this Content represents a redirect.
	 * Shorthand for getRedirectTarget() !== null.
	 *
	 * @since 1.21
	 *
	 * @return bool
	 */
	public function isRedirect();

	/**
	 * If this Content object is a redirect, this method updates the redirect target.
	 * Otherwise, it does nothing.
	 *
	 * @since 1.21
	 *
	 * @param Title $target the new redirect target
	 *
	 * @return Content a new Content object with the updated redirect (or $this if this Content object isn't a redirect)
	 */
	public function updateRedirect( Title $target );

	/**
	 * Returns the section with the given ID.
	 *
	 * @since 1.21
	 *
	 * @param string $sectionId The section's ID, given as a numeric string.
	 *    The ID "0" retrieves the section before the first heading, "1" the
	 *    text between the first heading (included) and the second heading
	 *    (excluded), etc.
	 * @return Content|Boolean|null The section, or false if no such section
	 *    exist, or null if sections are not supported.
	 */
	public function getSection( $sectionId );

	/**
	 * Replaces a section of the content and returns a Content object with the
	 * section replaced.
	 *
	 * @since 1.21
	 *
	 * @param $section null/false or a section number (0, 1, 2, T1, T2...), or "new"
	 * @param $with Content: new content of the section
	 * @param string $sectionTitle new section's subject, only if $section is 'new'
	 * @return string Complete article text, or null if error
	 */
	public function replaceSection( $section, Content $with, $sectionTitle = '' );

	/**
	 * Returns a Content object with pre-save transformations applied (or this
	 * object if no transformations apply).
	 *
	 * @since 1.21
	 *
	 * @param $title Title
	 * @param $user User
	 * @param $parserOptions null|ParserOptions
	 * @return Content
	 */
	public function preSaveTransform( Title $title, User $user, ParserOptions $parserOptions );

	/**
	 * Returns a new WikitextContent object with the given section heading
	 * prepended, if supported. The default implementation just returns this
	 * Content object unmodified, ignoring the section header.
	 *
	 * @since 1.21
	 *
	 * @param $header string
	 * @return Content
	 */
	public function addSectionHeader( $header );

	/**
	 * Returns a Content object with preload transformations applied (or this
	 * object if no transformations apply).
	 *
	 * @since 1.21
	 *
	 * @param $title Title
	 * @param $parserOptions null|ParserOptions
	 * @return Content
	 */
	public function preloadTransform( Title $title, ParserOptions $parserOptions );

	/**
	 * Prepare Content for saving. Called before Content is saved by WikiPage::doEditContent() and in
	 * similar places.
	 *
	 * This may be used to check the content's consistency with global state. This function should
	 * NOT write any information to the database.
	 *
	 * Note that this method will usually be called inside the same transaction bracket that will be used
	 * to save the new revision.
	 *
	 * Note that this method is called before any update to the page table is performed. This means that
	 * $page may not yet know a page ID.
	 *
	 * @since 1.21
	 *
	 * @param WikiPage $page The page to be saved.
	 * @param int      $flags bitfield for use with EDIT_XXX constants, see WikiPage::doEditContent()
	 * @param int      $baseRevId the ID of the current revision
	 * @param User     $user
	 *
	 * @return Status A status object indicating whether the content was successfully prepared for saving.
	 *                If the returned status indicates an error, a rollback will be performed and the
	 *                transaction aborted.
	 *
	 * @see see WikiPage::doEditContent()
	 */
	public function prepareSave( WikiPage $page, $flags, $baseRevId, User $user );

	/**
	 * Returns a list of updates to perform when this content is deleted.
	 * The necessary updates may be taken from the Content object, or depend on
	 * the current state of the database.
	 *
	 * @since 1.21
	 *
	 * @param $page WikiPage the deleted page
	 * @param $parserOutput null|ParserOutput optional parser output object
	 *    for efficient access to meta-information about the content object.
	 *    Provide if you have one handy.
	 *
	 * @return array A list of DataUpdate instances that will clean up the
	 *    database after deletion.
	 */
	public function getDeletionUpdates( WikiPage $page,
		ParserOutput $parserOutput = null );

	/**
	 * Returns true if this Content object matches the given magic word.
	 *
	 * @since 1.21
	 *
	 * @param MagicWord $word the magic word to match
	 *
	 * @return bool whether this Content object matches the given magic word.
	 */
	public function matchMagicWord( MagicWord $word );

	/**
	 * Converts this content object into another content object with the given content model,
	 * if that is possible.
	 *
	 * @param string  $toModel the desired content model, use the CONTENT_MODEL_XXX flags.
	 * @param string  $lossy flag, set to "lossy" to allow lossy conversion. If lossy conversion is
	 * not allowed, full round-trip conversion is expected to work without losing information.
	 *
	 * @return Content|bool A content object with the content model $toModel, or false if
	 * that conversion is not supported.
	 */
	public function convert( $toModel, $lossy = '' );

		// TODO: ImagePage and CategoryPage interfere with per-content action handlers
	// TODO: nice&sane integration of GeSHi syntax highlighting
	//   [11:59] <vvv> Hooks are ugly; make CodeHighlighter interface and a
	//   config to set the class which handles syntax highlighting
	//   [12:00] <vvv> And default it to a DummyHighlighter
}