MediaWiki REL1_33
WebPHandler.php
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1<?php
30 const BROKEN_FILE = '0'; // value to store in img_metadata if error extracting metadata.
34 const MINIMUM_CHUNK_HEADER_LENGTH = 18;
38 const _MW_WEBP_VERSION = 1;
39
40 const VP8X_ICC = 32;
41 const VP8X_ALPHA = 16;
42 const VP8X_EXIF = 8;
43 const VP8X_XMP = 4;
44 const VP8X_ANIM = 2;
45
46 public function getMetadata( $image, $filename ) {
47 $parsedWebPData = self::extractMetadata( $filename );
48 if ( !$parsedWebPData ) {
49 return self::BROKEN_FILE;
50 }
51
52 $parsedWebPData['metadata']['_MW_WEBP_VERSION'] = self::_MW_WEBP_VERSION;
53 return serialize( $parsedWebPData );
54 }
55
56 public function getMetadataType( $image ) {
57 return 'parsed-webp';
58 }
59
60 public function isMetadataValid( $image, $metadata ) {
61 if ( $metadata === self::BROKEN_FILE ) {
62 // Do not repetitivly regenerate metadata on broken file.
64 }
65
66 Wikimedia\suppressWarnings();
67 $data = unserialize( $metadata );
68 Wikimedia\restoreWarnings();
69
70 if ( !$data || !is_array( $data ) ) {
71 wfDebug( __METHOD__ . " invalid WebP metadata\n" );
72
73 return self::METADATA_BAD;
74 }
75
76 if ( !isset( $data['metadata']['_MW_WEBP_VERSION'] )
77 || $data['metadata']['_MW_WEBP_VERSION'] != self::_MW_WEBP_VERSION
78 ) {
79 wfDebug( __METHOD__ . " old but compatible WebP metadata\n" );
80
82 }
84 }
85
94 public static function extractMetadata( $filename ) {
95 wfDebugLog( 'WebP', __METHOD__ . ": Extracting metadata from $filename\n" );
96
97 $info = RiffExtractor::findChunksFromFile( $filename, 100 );
98 if ( $info === false ) {
99 wfDebugLog( 'WebP', __METHOD__ . ": Not a valid RIFF file\n" );
100 return false;
101 }
102
103 if ( $info['fourCC'] != 'WEBP' ) {
104 wfDebugLog( 'WebP', __METHOD__ . ': FourCC was not WEBP: ' .
105 bin2hex( $info['fourCC'] ) . " \n" );
106 return false;
107 }
108
109 $metadata = self::extractMetadataFromChunks( $info['chunks'], $filename );
110 if ( !$metadata ) {
111 wfDebugLog( 'WebP', __METHOD__ . ": No VP8 chunks found\n" );
112 return false;
113 }
114
115 return $metadata;
116 }
117
125 public static function extractMetadataFromChunks( $chunks, $filename ) {
126 $vp8Info = [];
127
128 foreach ( $chunks as $chunk ) {
129 if ( !in_array( $chunk['fourCC'], [ 'VP8 ', 'VP8L', 'VP8X' ] ) ) {
130 // Not a chunk containing interesting metadata
131 continue;
132 }
133
134 $chunkHeader = file_get_contents( $filename, false, null,
135 $chunk['start'], self::MINIMUM_CHUNK_HEADER_LENGTH );
136 wfDebugLog( 'WebP', __METHOD__ . ": {$chunk['fourCC']}\n" );
137
138 switch ( $chunk['fourCC'] ) {
139 case 'VP8 ':
140 return array_merge( $vp8Info,
141 self::decodeLossyChunkHeader( $chunkHeader ) );
142 case 'VP8L':
143 return array_merge( $vp8Info,
144 self::decodeLosslessChunkHeader( $chunkHeader ) );
145 case 'VP8X':
146 $vp8Info = array_merge( $vp8Info,
147 self::decodeExtendedChunkHeader( $chunkHeader ) );
148 // Continue looking for other chunks to improve the metadata
149 break;
150 }
151 }
152 return $vp8Info;
153 }
154
160 protected static function decodeLossyChunkHeader( $header ) {
161 // Bytes 0-3 are 'VP8 '
162 // Bytes 4-7 are the VP8 stream size
163 // Bytes 8-10 are the frame tag
164 // Bytes 11-13 are 0x9D 0x01 0x2A called the sync code
165 $syncCode = substr( $header, 11, 3 );
166 if ( $syncCode != "\x9D\x01\x2A" ) {
167 wfDebugLog( 'WebP', __METHOD__ . ': Invalid sync code: ' .
168 bin2hex( $syncCode ) . "\n" );
169 return [];
170 }
171 // Bytes 14-17 are image size
172 $imageSize = unpack( 'v2', substr( $header, 14, 4 ) );
173 // Image sizes are 14 bit, 2 MSB are scaling parameters which are ignored here
174 return [
175 'compression' => 'lossy',
176 'width' => $imageSize[1] & 0x3FFF,
177 'height' => $imageSize[2] & 0x3FFF
178 ];
179 }
180
186 public static function decodeLosslessChunkHeader( $header ) {
187 // Bytes 0-3 are 'VP8L'
188 // Bytes 4-7 are chunk stream size
189 // Byte 8 is 0x2F called the signature
190 if ( $header{8} != "\x2F" ) {
191 wfDebugLog( 'WebP', __METHOD__ . ': Invalid signature: ' .
192 bin2hex( $header{8} ) . "\n" );
193 return [];
194 }
195 // Bytes 9-12 contain the image size
196 // Bits 0-13 are width-1; bits 15-27 are height-1
197 $imageSize = unpack( 'C4', substr( $header, 9, 4 ) );
198 return [
199 'compression' => 'lossless',
200 'width' => ( $imageSize[1] | ( ( $imageSize[2] & 0x3F ) << 8 ) ) + 1,
201 'height' => ( ( ( $imageSize[2] & 0xC0 ) >> 6 ) |
202 ( $imageSize[3] << 2 ) | ( ( $imageSize[4] & 0x03 ) << 10 ) ) + 1
203 ];
204 }
205
211 public static function decodeExtendedChunkHeader( $header ) {
212 // Bytes 0-3 are 'VP8X'
213 // Byte 4-7 are chunk length
214 // Byte 8-11 are a flag bytes
215 $flags = unpack( 'c', substr( $header, 8, 1 ) );
216
217 // Byte 12-17 are image size (24 bits)
218 $width = unpack( 'V', substr( $header, 12, 3 ) . "\x00" );
219 $height = unpack( 'V', substr( $header, 15, 3 ) . "\x00" );
220
221 return [
222 'compression' => 'unknown',
223 'animated' => ( $flags[1] & self::VP8X_ANIM ) == self::VP8X_ANIM,
224 'transparency' => ( $flags[1] & self::VP8X_ALPHA ) == self::VP8X_ALPHA,
225 'width' => ( $width[1] & 0xFFFFFF ) + 1,
226 'height' => ( $height[1] & 0xFFFFFF ) + 1
227 ];
228 }
229
230 public function getImageSize( $file, $path, $metadata = false ) {
231 if ( $file === null ) {
232 $metadata = self::getMetadata( $file, $path );
233 }
234 if ( $metadata === false && $file instanceof File ) {
235 $metadata = $file->getMetadata();
236 }
237
238 Wikimedia\suppressWarnings();
239 $metadata = unserialize( $metadata );
240 Wikimedia\restoreWarnings();
241
242 if ( $metadata == false ) {
243 return false;
244 }
245 return [ $metadata['width'], $metadata['height'] ];
246 }
247
252 public function mustRender( $file ) {
253 return true;
254 }
255
260 public function canRender( $file ) {
261 if ( self::isAnimatedImage( $file ) ) {
262 return false;
263 }
264 return true;
265 }
266
271 public function isAnimatedImage( $image ) {
272 $ser = $image->getMetadata();
273 if ( $ser ) {
274 $metadata = unserialize( $ser );
275 if ( isset( $metadata['animated'] ) && $metadata['animated'] === true ) {
276 return true;
277 }
278 }
279
280 return false;
281 }
282
283 public function canAnimateThumbnail( $file ) {
284 return false;
285 }
286
295 public function getThumbType( $ext, $mime, $params = null ) {
296 return [ 'png', 'image/png' ];
297 }
298
306 protected function getScalerType( $dstPath, $checkDstPath = true ) {
307 return 'im';
308 }
309}
serialize()
unserialize( $serialized)
wfDebug( $text, $dest='all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
wfDebugLog( $logGroup, $text, $dest='all', array $context=[])
Send a line to a supplementary debug log file, if configured, or main debug log if not.
Generic handler for bitmap images.
Implements some public methods and some protected utility functions which are required by multiple ch...
Definition File.php:52
const METADATA_COMPATIBLE
const METADATA_GOOD
static findChunksFromFile( $filename, $maxChunks=-1)
Handler for Google's WebP format https://developers.google.com/speed/webp/
mustRender( $file)
const VP8X_ALPHA
isMetadataValid( $image, $metadata)
Check if the metadata string is valid for this handler.
canAnimateThumbnail( $file)
If the material is animated, we can animate the thumbnail.
static extractMetadataFromChunks( $chunks, $filename)
Extracts the image size and WebP type from a file based on the chunk list.
isAnimatedImage( $image)
getMetadata( $image, $filename)
Get handler-specific metadata which will be saved in the img_metadata field.
getScalerType( $dstPath, $checkDstPath=true)
Must use "im" for XCF.
static decodeLossyChunkHeader( $header)
Decodes a lossy chunk header.
getImageSize( $file, $path, $metadata=false)
const BROKEN_FILE
const VP8X_EXIF
canRender( $file)
const VP8X_ANIM
getThumbType( $ext, $mime, $params=null)
Render files as PNG.
static decodeLosslessChunkHeader( $header)
Decodes a lossless chunk header.
getMetadataType( $image)
Get a string describing the type of metadata, for display purposes.
static extractMetadata( $filename)
Extracts the image size and WebP type from a file.
static decodeExtendedChunkHeader( $header)
Decodes an extended chunk header.
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Definition hooks.txt:886
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Definition injection.txt:37
if(!is_readable( $file)) $ext
Definition router.php:48
if(PHP_SAPI !='cli-server') if(!isset( $_SERVER['SCRIPT_FILENAME'])) $file
Definition router.php:42
$params
$header