--- /dev/null
+<?php
+/**
+ * Handler for Google's WebP format <https://developers.google.com/speed/webp/>
+ *
+ * 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
+ *
+ * @file
+ * @ingroup Media
+ */
+
+/**
+ * Handler for Google's WebP format <https://developers.google.com/speed/webp/>
+ *
+ * @ingroup Media
+ */
+class WebPHandler extends BitmapHandler {
+ const BROKEN_FILE = '0'; // value to store in img_metadata if error extracting metadata.
+ /**
+ * @var int Minimum chunk header size to be able to read all header types
+ */
+ const MINIMUM_CHUNK_HEADER_LENGTH = 18;
+ /**
+ * @var int version of the metadata stored in db records
+ */
+ const _MW_WEBP_VERSION = 1;
+
+ const VP8X_ICC = 32;
+ const VP8X_ALPHA = 16;
+ const VP8X_EXIF = 8;
+ const VP8X_XMP = 4;
+ const VP8X_ANIM = 2;
+
+ public function getMetadata( $image, $filename ) {
+ $parsedWebPData = self::extractMetadata( $filename );
+ if ( !$parsedWebPData ) {
+ return self::BROKEN_FILE;
+ }
+
+ $parsedWebPData['metadata']['_MW_WEBP_VERSION'] = self::_MW_WEBP_VERSION;
+ return serialize( $parsedWebPData );
+ }
+
+ public function getMetadataType( $image ) {
+ return 'parsed-webp';
+ }
+
+ public function isMetadataValid( $image, $metadata ) {
+ if ( $metadata === self::BROKEN_FILE ) {
+ // Do not repetitivly regenerate metadata on broken file.
+ return self::METADATA_GOOD;
+ }
+
+ MediaWiki\suppressWarnings();
+ $data = unserialize( $metadata );
+ MediaWiki\restoreWarnings();
+
+ if ( !$data || !is_array( $data ) ) {
+ wfDebug( __METHOD__ . " invalid WebP metadata\n" );
+
+ return self::METADATA_BAD;
+ }
+
+ if ( !isset( $data['metadata']['_MW_WEBP_VERSION'] )
+ || $data['metadata']['_MW_WEBP_VERSION'] != self::_MW_WEBP_VERSION
+ ) {
+ wfDebug( __METHOD__ . " old but compatible WebP metadata\n" );
+
+ return self::METADATA_COMPATIBLE;
+ }
+ return self::METADATA_GOOD;
+ }
+
+ /**
+ * Extracts the image size and WebP type from a file
+ *
+ * @param string $filename
+ * @return array|bool Header data array with entries 'compression', 'width' and 'height',
+ * where 'compression' can be 'lossy', 'lossless', 'animated' or 'unknown'. False if
+ * file is not a valid WebP file.
+ */
+ public static function extractMetadata( $filename ) {
+ wfDebugLog( 'WebP', __METHOD__ . ": Extracting metadata from $filename\n" );
+
+ $info = RiffExtractor::findChunksFromFile( $filename, 100 );
+ if ( $info === false ) {
+ wfDebugLog( 'WebP', __METHOD__ . ": Not a valid RIFF file\n" );
+ return false;
+ }
+
+ if ( $info['fourCC'] != 'WEBP' ) {
+ wfDebugLog( 'WebP', __METHOD__ . ': FourCC was not WEBP: ' .
+ bin2hex( $info['fourCC'] ) . " \n" );
+ return false;
+ }
+
+ $metadata = self::extractMetadataFromChunks( $info['chunks'], $filename );
+ if ( !$metadata ) {
+ wfDebugLog( 'WebP', __METHOD__ . ": No VP8 chunks found\n" );
+ return false;
+ }
+
+ return $metadata;
+ }
+
+ /**
+ * Extracts the image size and WebP type from a file based on the chunk list
+ * @param array $chunks Chunks as extracted by RiffExtractor
+ * @param string $filename
+ * @return array Header data array with entries 'compression', 'width' and 'height', where
+ * 'compression' can be 'lossy', 'lossless', 'animated' or 'unknown'
+ */
+ public static function extractMetadataFromChunks( $chunks, $filename ) {
+ $vp8Info = [];
+
+ foreach ( $chunks as $chunk ) {
+ if ( !in_array( $chunk['fourCC'], [ 'VP8 ', 'VP8L', 'VP8X' ] ) ) {
+ // Not a chunk containing interesting metadata
+ continue;
+ }
+
+ $chunkHeader = file_get_contents( $filename, false, null,
+ $chunk['start'], self::MINIMUM_CHUNK_HEADER_LENGTH );
+ wfDebugLog( 'WebP', __METHOD__ . ": {$chunk['fourCC']}\n" );
+
+ switch ( $chunk['fourCC'] ) {
+ case 'VP8 ':
+ return array_merge( $vp8Info,
+ self::decodeLossyChunkHeader( $chunkHeader ) );
+ case 'VP8L':
+ return array_merge( $vp8Info,
+ self::decodeLosslessChunkHeader( $chunkHeader ) );
+ case 'VP8X':
+ $vp8Info = array_merge( $vp8Info,
+ self::decodeExtendedChunkHeader( $chunkHeader ) );
+ // Continue looking for other chunks to improve the metadata
+ break;
+ }
+ }
+ return $vp8Info;
+ }
+
+ /**
+ * Decodes a lossy chunk header
+ * @param string $header Header string
+ * @return bool|array See WebPHandler::decodeHeader
+ */
+ protected static function decodeLossyChunkHeader( $header ) {
+ // Bytes 0-3 are 'VP8 '
+ // Bytes 4-7 are the VP8 stream size
+ // Bytes 8-10 are the frame tag
+ // Bytes 11-13 are 0x9D 0x01 0x2A called the sync code
+ $syncCode = substr( $header, 11, 3 );
+ if ( $syncCode != "\x9D\x01\x2A" ) {
+ wfDebugLog( 'WebP', __METHOD__ . ': Invalid sync code: ' .
+ bin2hex( $syncCode ) . "\n" );
+ return [];
+ }
+ // Bytes 14-17 are image size
+ $imageSize = unpack( 'v2', substr( $header, 14, 4 ) );
+ // Image sizes are 14 bit, 2 MSB are scaling parameters which are ignored here
+ return [
+ 'compression' => 'lossy',
+ 'width' => $imageSize[1] & 0x3FFF,
+ 'height' => $imageSize[2] & 0x3FFF
+ ];
+ }
+
+ /**
+ * Decodes a lossless chunk header
+ * @param string $header Header string
+ * @return bool|array See WebPHandler::decodeHeader
+ */
+ public static function decodeLosslessChunkHeader( $header ) {
+ // Bytes 0-3 are 'VP8L'
+ // Bytes 4-7 are chunk stream size
+ // Byte 8 is 0x2F called the signature
+ if ( $header{8} != "\x2F" ) {
+ wfDebugLog( 'WebP', __METHOD__ . ': Invalid signature: ' .
+ bin2hex( $header{8} ) . "\n" );
+ return [];
+ }
+ // Bytes 9-12 contain the image size
+ // Bits 0-13 are width-1; bits 15-27 are height-1
+ $imageSize = unpack( 'C4', substr( $header, 9, 4 ) );
+ return [
+ 'compression' => 'lossless',
+ 'width' => ( $imageSize[1] | ( ( $imageSize[2] & 0x3F ) << 8 ) ) + 1,
+ 'height' => ( ( ( $imageSize[2] & 0xC0 ) >> 6 ) |
+ ( $imageSize[3] << 2 ) | ( ( $imageSize[4] & 0x03 ) << 10 ) ) + 1
+ ];
+ }
+
+ /**
+ * Decodes an extended chunk header
+ * @param string $header Header string
+ * @return bool|array See WebPHandler::decodeHeader
+ */
+ public static function decodeExtendedChunkHeader( $header ) {
+ // Bytes 0-3 are 'VP8X'
+ // Byte 4-7 are chunk length
+ // Byte 8-11 are a flag bytes
+ $flags = unpack( 'c', substr( $header, 8, 1 ) );
+
+ // Byte 12-17 are image size (24 bits)
+ $width = unpack( 'V', substr( $header, 12, 3 ) . "\x00" );
+ $height = unpack( 'V', substr( $header, 15, 3 ) . "\x00" );
+
+ return [
+ 'compression' => 'unknown',
+ 'animated' => ( $flags[1] & self::VP8X_ANIM ) == self::VP8X_ANIM,
+ 'transparency' => ( $flags[1] & self::VP8X_ALPHA ) == self::VP8X_ALPHA,
+ 'width' => ( $width[1] & 0xFFFFFF ) + 1,
+ 'height' => ( $height[1] & 0xFFFFFF ) + 1
+ ];
+ }
+
+ public function getImageSize( $file, $path, $metadata = false ) {
+ if ( $file === null ) {
+ $metadata = self::getMetadata( $file, $path );
+ }
+ if ( $metadata === false && $file instanceof File ) {
+ $metadata = $file->getMetadata();
+ }
+
+ MediaWiki\suppressWarnings();
+ $metadata = unserialize( $metadata );
+ MediaWiki\restoreWarnings();
+
+ if ( $metadata == false ) {
+ return false;
+ }
+ return [ $metadata['width'], $metadata['height'] ];
+ }
+
+ /**
+ * @param File $file
+ * @return bool True, not all browsers support WebP
+ */
+ public function mustRender( $file ) {
+ return true;
+ }
+
+ /**
+ * @param File $file
+ * @return bool False if we are unable to render this image
+ */
+ public function canRender( $file ) {
+ if ( self::isAnimatedImage( $file ) ) {
+ return false;
+ }
+ return true;
+ }
+
+ /**
+ * @param File $image
+ * @return bool
+ */
+ public function isAnimatedImage( $image ) {
+ $ser = $image->getMetadata();
+ if ( $ser ) {
+ $metadata = unserialize( $ser );
+ if ( isset( $metadata['animated'] ) && $metadata['animated'] === true ) {
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ public function canAnimateThumbnail( $file ) {
+ return false;
+ }
+
+ /**
+ * Render files as PNG
+ *
+ * @param string $ext
+ * @param string $mime
+ * @param array|null $params
+ * @return array
+ */
+ public function getThumbType( $ext, $mime, $params = null ) {
+ return [ 'png', 'image/png' ];
+ }
+
+ /**
+ * Must use "im" for XCF
+ *
+ * @param string $dstPath
+ * @param bool $checkDstPath
+ * @return string
+ */
+ protected function getScalerType( $dstPath, $checkDstPath = true ) {
+ return 'im';
+ }
+}
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff