1<?php
2/**
3 * Handler for bitmap images with exif metadata.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
19 *
20 * @file
21 * @ingroup Media
22 */
23
24/**
25 * Stuff specific to JPEG and (built-in) TIFF handler.
26 * All metadata related, since both JPEG and TIFF support Exif.
27 *
28 * @stable to extend
29 * @ingroup Media
30 */
31class ExifBitmapHandler extends BitmapHandler {
32	/** Error extracting metadata */
33	public const BROKEN_FILE = '-1';
34
35	/** Outdated error extracting metadata */
36	public const OLD_BROKEN_FILE = '0';
37
38	public function convertMetadataVersion( $metadata, $version = 1 ) {
39		// basically flattens arrays.
40		$version = intval( explode( ';', $version, 2 )[0] );
41		if ( $version < 1 || $version >= 2 ) {
42			return $metadata;
43		}
44
45		$avoidHtml = true;
46
47		if ( !is_array( $metadata ) ) {
48			$metadata = unserialize( $metadata );
49		}
50		if ( !isset( $metadata['MEDIAWIKI_EXIF_VERSION'] ) || $metadata['MEDIAWIKI_EXIF_VERSION'] != 2 ) {
51			return $metadata;
52		}
53
54		// Treat Software as a special case because in can contain
55		// an array of (SoftwareName, Version).
56		if ( isset( $metadata['Software'] )
57			&& is_array( $metadata['Software'] )
58			&& is_array( $metadata['Software'][0] )
59			&& isset( $metadata['Software'][0][0] )
60			&& isset( $metadata['Software'][0][1] )
61		) {
62			$metadata['Software'] = $metadata['Software'][0][0] . ' (Version '
63				. $metadata['Software'][0][1] . ')';
64		}
65
66		$formatter = new FormatMetadata;
67
68		// ContactInfo also has to be dealt with specially
69		if ( isset( $metadata['Contact'] ) ) {
70			$metadata['Contact'] =
71				$formatter->collapseContactInfo(
72					$metadata['Contact'] );
73		}
74
75		foreach ( $metadata as &$val ) {
76			if ( is_array( $val ) ) {
77				$val = $formatter->flattenArrayReal( $val, 'ul', $avoidHtml );
78			}
79		}
80		$metadata['MEDIAWIKI_EXIF_VERSION'] = 1;
81
82		return $metadata;
83	}
84
85	/**
86	 * @param File $image
87	 * @param string $metadata
88	 * @return bool|int
89	 */
90	public function isMetadataValid( $image, $metadata ) {
91		global $wgShowEXIF;
92		if ( !$wgShowEXIF ) {
93			# Metadata disabled and so an empty field is expected
94			return self::METADATA_GOOD;
95		}
96		if ( $metadata === self::OLD_BROKEN_FILE ) {
97			# Old special value indicating that there is no Exif data in the file.
98			# or that there was an error well extracting the metadata.
99			wfDebug( __METHOD__ . ": back-compat version" );
100
101			return self::METADATA_COMPATIBLE;
102		}
103		if ( $metadata === self::BROKEN_FILE ) {
104			return self::METADATA_GOOD;
105		}
106		Wikimedia\suppressWarnings();
107		$exif = unserialize( $metadata );
108		Wikimedia\restoreWarnings();
109		if ( !isset( $exif['MEDIAWIKI_EXIF_VERSION'] )
110			|| $exif['MEDIAWIKI_EXIF_VERSION'] != Exif::version()
111		) {
112			if ( isset( $exif['MEDIAWIKI_EXIF_VERSION'] )
113				&& $exif['MEDIAWIKI_EXIF_VERSION'] == 1
114			) {
115				// back-compatible but old
116				wfDebug( __METHOD__ . ": back-compat version" );
117
118				return self::METADATA_COMPATIBLE;
119			}
120			# Wrong (non-compatible) version
121			wfDebug( __METHOD__ . ": wrong version" );
122
123			return self::METADATA_BAD;
124		}
125
126		return self::METADATA_GOOD;
127	}
128
129	/**
130	 * @param File $image
131	 * @param bool|IContextSource $context Context to use (optional)
132	 * @return array|bool
133	 */
134	public function formatMetadata( $image, $context = false ) {
135		$meta = $this->getCommonMetaArray( $image );
136		if ( count( $meta ) === 0 ) {
137			return false;
138		}
139
140		return $this->formatMetadataHelper( $meta, $context );
141	}
142
143	public function getCommonMetaArray( File $file ) {
144		$metadata = $file->getMetadata();
145		if ( $metadata === self::OLD_BROKEN_FILE
146			|| $metadata === self::BROKEN_FILE
147			|| $this->isMetadataValid( $file, $metadata ) === self::METADATA_BAD
148		) {
149			// So we don't try and display metadata from PagedTiffHandler
150			// for example when using InstantCommons.
151			return [];
152		}
153
154		$exif = unserialize( $metadata );
155		if ( !$exif ) {
156			return [];
157		}
158		unset( $exif['MEDIAWIKI_EXIF_VERSION'] );
159
160		return $exif;
161	}
162
163	public function getMetadataType( $image ) {
164		return 'exif';
165	}
166
167	/**
168	 * Wrapper for base classes ImageHandler::getImageSize() that checks for
169	 * rotation reported from metadata and swaps the sizes to match.
170	 *
171	 * @param File|FSFile $image
172	 * @param string $path
173	 * @return array|false
174	 */
175	public function getImageSize( $image, $path ) {
176		$gis = parent::getImageSize( $image, $path );
177
178		// Don't just call $image->getMetadata(); FSFile::getPropsFromPath() calls us with a bogus object.
179		// This may mean we read EXIF data twice on initial upload.
180		if ( $this->autoRotateEnabled() ) {
181			$meta = $this->getMetadata( $image, $path );
182			$rotation = $this->getRotationForExif( $meta );
183		} else {
184			$rotation = 0;
185		}
186
187		if ( $rotation == 90 || $rotation == 270 ) {
188			$width = $gis[0];
189			$gis[0] = $gis[1];
190			$gis[1] = $width;
191		}
192
193		return $gis;
194	}
195
196	/**
197	 * On supporting image formats, try to read out the low-level orientation
198	 * of the file and return the angle that the file needs to be rotated to
199	 * be viewed.
200	 *
201	 * This information is only useful when manipulating the original file;
202	 * the width and height we normally work with is logical, and will match
203	 * any produced output views.
204	 *
205	 * @param File $file
206	 * @return int 0, 90, 180 or 270
207	 */
208	public function getRotation( $file ) {
209		if ( !$this->autoRotateEnabled() ) {
210			return 0;
211		}
212
213		$data = $file->getMetadata();
214
215		return $this->getRotationForExif( $data );
216	}
217
218	/**
219	 * Given a chunk of serialized Exif metadata, return the orientation as
220	 * degrees of rotation.
221	 *
222	 * @param string $data
223	 * @return int 0, 90, 180 or 270
224	 * @todo FIXME: Orientation can include flipping as well; see if this is an issue!
225	 */
226	protected function getRotationForExif( $data ) {
227		if ( !$data ) {
228			return 0;
229		}
230		Wikimedia\suppressWarnings();
231		$data = unserialize( $data );
232		Wikimedia\restoreWarnings();
233		if ( isset( $data['Orientation'] ) ) {
234			# See http://sylvana.net/jpegcrop/exif_orientation.html
235			switch ( $data['Orientation'] ) {
236				case 8:
237					return 90;
238				case 3:
239					return 180;
240				case 6:
241					return 270;
242				default:
243					return 0;
244			}
245		}
246
247		return 0;
248	}
249}
250