MediaWiki  master
WebPHandler.php
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1 <?php
29 class WebPHandler extends BitmapHandler {
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.
63  return self::METADATA_GOOD;
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 
81  return self::METADATA_COMPATIBLE;
82  }
83  return self::METADATA_GOOD;
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 }
$data
Utility to generate mapping file used in mw.Title (phpCharToUpper.json)
getThumbType( $ext, $mime, $params=null)
Render files as PNG.
serialize()
if(PHP_SAPI !='cli-server') if(!isset( $_SERVER['SCRIPT_FILENAME'])) $file
Definition: router.php:42
static extractMetadata( $filename)
Extracts the image size and WebP type from a file.
Definition: WebPHandler.php:94
isAnimatedImage( $image)
canRender( $file)
getScalerType( $dstPath, $checkDstPath=true)
Must use "im" for XCF.
Handler for Google&#39;s WebP format https://developers.google.com/speed/webp/
Definition: WebPHandler.php:29
mustRender( $file)
const VP8X_XMP
Definition: WebPHandler.php:43
static decodeLosslessChunkHeader( $header)
Decodes a lossless chunk header.
wfDebug( $text, $dest='all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
getMetadata( $image, $filename)
Definition: WebPHandler.php:46
static decodeLossyChunkHeader( $header)
Decodes a lossy chunk header.
$params
unserialize( $serialized)
this hook is for auditing only or null if authentication failed before getting that far or null if we can t even determine that When $user is not null
Definition: hooks.txt:780
$header
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Definition: distributors.txt:9
getImageSize( $file, $path, $metadata=false)
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
canAnimateThumbnail( $file)
wfDebugLog( $logGroup, $text, $dest='all', array $context=[])
Send a line to a supplementary debug log file, if configured, or main debug log if not...
this hook is for auditing only or null if authentication failed before getting that far or null if we can t even determine that When $user is not it can be in the form of< username >< more info > e g for bot passwords intended to be added to log contexts Fields it might only if the login was with a bot password it is not rendered in wiki pages or galleries in category pages allow injecting custom HTML after the section Any uses of the hook need to handle escaping see BaseTemplate::getToolbox and BaseTemplate::makeListItem for details on the format of individual items inside of this array or by returning and letting standard HTTP rendering take place modifiable or by returning false and taking over the output modifiable modifiable after all normalizations have been except for the $wgMaxImageArea check $image
Definition: hooks.txt:780
const VP8X_ALPHA
Definition: WebPHandler.php:41
static findChunksFromFile( $filename, $maxChunks=-1)
static extractMetadataFromChunks( $chunks, $filename)
Extracts the image size and WebP type from a file based on the chunk list.
isMetadataValid( $image, $metadata)
Definition: WebPHandler.php:60
if(!is_readable( $file)) $ext
Definition: router.php:48
getMetadataType( $image)
Definition: WebPHandler.php:56
Generic handler for bitmap images.
const VP8X_ANIM
Definition: WebPHandler.php:44
const BROKEN_FILE
Definition: WebPHandler.php:30
Implements some public methods and some protected utility functions which are required by multiple ch...
Definition: File.php:52
const VP8X_ICC
Definition: WebPHandler.php:40
const VP8X_EXIF
Definition: WebPHandler.php:42
static decodeExtendedChunkHeader( $header)
Decodes an extended chunk header.