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DjVuHandler.php
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DjVuHandler.php
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<?php
/**
* Handler for DjVu images.
*
* 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
*/
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\PoolCounter\PoolCounterWorkViaCallback;
use MediaWiki\Shell\Shell;
/**
* Handler for DjVu images
*
* @ingroup Media
*/
class DjVuHandler extends ImageHandler {
private const EXPENSIVE_SIZE_LIMIT = 10_485_760; // 10MiB
// Constants for getHandlerState
private const STATE_DJVU_IMAGE = 'djvuImage';
private const STATE_TEXT_TREE = 'djvuTextTree';
private const STATE_META_TREE = 'djvuMetaTree';
private const CACHE_VERSION = 'v2';
/**
* @return bool
*/
public function isEnabled() {
$djvuRenderer = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::DjvuRenderer );
$djvuDump = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::DjvuDump );
if ( !$djvuRenderer || !$djvuDump ) {
wfDebug( "DjVu is disabled, please set \$wgDjvuRenderer and \$wgDjvuDump" );
return false;
}
return true;
}
/**
* @param File $file
* @return bool
*/
public function mustRender( $file ) {
return true;
}
/**
* True if creating thumbnails from the file is large or otherwise resource-intensive.
* @param File $file
* @return bool
*/
public function isExpensiveToThumbnail( $file ) {
return $file->getSize() > static::EXPENSIVE_SIZE_LIMIT;
}
/**
* @param File $file
* @return bool
*/
public function isMultiPage( $file ) {
return true;
}
/**
* @return array
*/
public function getParamMap() {
return [
'img_width' => 'width',
'img_page' => 'page',
];
}
/**
* @param string $name
* @param mixed $value
* @return bool
*/
public function validateParam( $name, $value ) {
if ( $name === 'page' && trim( $value ) !== (string)intval( $value ) ) {
// Extra junk on the end of page, probably actually a caption
// e.g. [[File:Foo.djvu|thumb|Page 3 of the document shows foo]]
return false;
}
return in_array( $name, [ 'width', 'height', 'page' ] ) && $value > 0;
}
/**
* @param array $params
* @return string|false
*/
public function makeParamString( $params ) {
$page = $params['page'] ?? 1;
if ( !isset( $params['width'] ) ) {
return false;
}
return "page{$page}-{$params['width']}px";
}
/**
* @param string $str
* @return array|false
*/
public function parseParamString( $str ) {
$m = false;
if ( preg_match( '/^page(\d+)-(\d+)px$/', $str, $m ) ) {
return [ 'width' => $m[2], 'page' => $m[1] ];
}
return false;
}
/**
* @param array $params
* @return array
*/
protected function getScriptParams( $params ) {
return [
'width' => $params['width'],
'page' => $params['page'],
];
}
/**
* @param File $image
* @param string $dstPath
* @param string $dstUrl
* @param array $params
* @param int $flags
* @return MediaTransformError|ThumbnailImage|TransformParameterError
*/
public function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
$djvuRenderer = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::DjvuRenderer );
$djvuPostProcessor = MediaWikiServices::getInstance()->getMainConfig()
->get( MainConfigNames::DjvuPostProcessor );
if ( !$this->normaliseParams( $image, $params ) ) {
return new TransformParameterError( $params );
}
$width = $params['width'];
$height = $params['height'];
$page = $params['page'];
if ( $flags & self::TRANSFORM_LATER ) {
$params = [
'width' => $width,
'height' => $height,
'page' => $page
];
return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
}
if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
return new MediaTransformError(
'thumbnail_error',
$width,
$height,
wfMessage( 'thumbnail_dest_directory' )
);
}
// Get local copy source for shell scripts
// Thumbnail extraction is very inefficient for large files.
// Provide a way to pool count limit the number of downloaders.
if ( $image->getSize() >= 1e7 ) { // 10 MB
$work = new PoolCounterWorkViaCallback( 'GetLocalFileCopy', sha1( $image->getName() ),
[
'doWork' => static function () use ( $image ) {
return $image->getLocalRefPath();
}
]
);
$srcPath = $work->execute();
} else {
$srcPath = $image->getLocalRefPath();
}
if ( $srcPath === false ) { // Failed to get local copy
wfDebugLog( 'thumbnail',
sprintf( 'Thumbnail failed on %s: could not get local copy of "%s"',
wfHostname(), $image->getName() ) );
return new MediaTransformError( 'thumbnail_error',
$params['width'], $params['height'],
wfMessage( 'filemissing' )
);
}
# Use a subshell (brackets) to aggregate stderr from both pipeline commands
# before redirecting it to the overall stdout. This works in both Linux and Windows XP.
$cmd = '(' . Shell::escape(
$djvuRenderer,
"-format=ppm",
"-page={$page}",
"-size={$params['physicalWidth']}x{$params['physicalHeight']}",
$srcPath );
if ( $djvuPostProcessor ) {
$cmd .= " | {$djvuPostProcessor}";
}
$cmd .= ' > ' . Shell::escape( $dstPath ) . ') 2>&1';
wfDebug( __METHOD__ . ": $cmd" );
$retval = 0;
$err = wfShellExec( $cmd, $retval );
$removed = $this->removeBadFile( $dstPath, $retval );
if ( $retval !== 0 || $removed ) {
$this->logErrorForExternalProcess( $retval, $err, $cmd );
return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
}
$params = [
'width' => $width,
'height' => $height,
'page' => $page
];
return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
}
/**
* Cache an instance of DjVuImage in a MediaHandlerState object, return
* that instance
*
* @param MediaHandlerState $state
* @param string $path
* @return DjVuImage
*/
private function getDjVuImage( $state, $path ) {
$deja = $state->getHandlerState( self::STATE_DJVU_IMAGE );
if ( !$deja ) {
$deja = new DjVuImage( $path );
$state->setHandlerState( self::STATE_DJVU_IMAGE, $deja );
}
return $deja;
}
/**
* Get metadata, unserializing it if necessary.
*
* @param File $file The DjVu file in question
* @param bool $gettext
* @return string|false|array metadata
*/
private function getMetadataInternal( File $file, $gettext ) {
$itemNames = [ 'error', '_error', 'data' ];
if ( $gettext ) {
$itemNames[] = 'text';
}
$unser = $file->getMetadataItems( $itemNames );
if ( isset( $unser['error'] ) ) {
return false;
}
if ( isset( $unser['_error'] ) ) {
return false;
}
return $unser;
}
/**
* Cache a document tree for the DjVu metadata
* @param File $image
* @param bool $gettext DOCUMENT (Default: false)
* @return false|array
*/
public function getMetaTree( $image, $gettext = false ) {
if ( $gettext && $image->getHandlerState( self::STATE_TEXT_TREE ) ) {
return $image->getHandlerState( self::STATE_TEXT_TREE );
}
if ( !$gettext && $image->getHandlerState( self::STATE_META_TREE ) ) {
return $image->getHandlerState( self::STATE_META_TREE );
}
$metadata = $this->getMetadataInternal( $image, $gettext );
if ( !$metadata ) {
return false;
}
if ( !$gettext ) {
unset( $metadata['text'] );
}
return $metadata;
}
public function getThumbType( $ext, $mime, $params = null ) {
$djvuOutputExtension = MediaWikiServices::getInstance()->getMainConfig()
->get( MainConfigNames::DjvuOutputExtension );
static $mime;
if ( !isset( $mime ) ) {
$magic = MediaWikiServices::getInstance()->getMimeAnalyzer();
$mime = $magic->getMimeTypeFromExtensionOrNull( $djvuOutputExtension );
}
return [ $djvuOutputExtension, $mime ];
}
public function getSizeAndMetadata( $state, $path ) {
wfDebug( "Getting DjVu metadata for $path" );
$djvuImage = $this->getDjVuImage( $state, $path );
$metadata = $djvuImage->retrieveMetaData();
if ( $metadata === false ) {
// Special value so that we don't repetitively try and decode a broken file.
$metadata = [ 'error' => 'Error extracting metadata' ];
}
return [ 'metadata' => $metadata ] + $djvuImage->getImageSize();
}
public function getMetadataType( $image ) {
// historical reasons
return 'djvuxml';
}
public function isFileMetadataValid( $image ) {
return $image->getMetadataArray() ? self::METADATA_GOOD : self::METADATA_BAD;
}
public function pageCount( File $image ) {
$info = $this->getDimensionInfo( $image );
return $info ? $info['pageCount'] : false;
}
public function getPageDimensions( File $image, $page ) {
$index = $page - 1; // MW starts pages at 1
$info = $this->getDimensionInfo( $image );
if ( $info && isset( $info['dimensionsByPage'][$index] ) ) {
return $info['dimensionsByPage'][$index];
}
return false;
}
protected function getDimensionInfo( File $file ) {
$cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
return $cache->getWithSetCallback(
$cache->makeKey( 'file-djvu', 'dimensions', self::CACHE_VERSION, $file->getSha1() ),
$cache::TTL_INDEFINITE,
function () use ( $file ) {
$tree = $this->getMetaTree( $file );
return $this->getDimensionInfoFromMetaTree( $tree );
},
[ 'pcTTL' => $cache::TTL_INDEFINITE ]
);
}
/**
* Given the metadata, returns dimension information about the document
* @param false|array $metatree The file's metadata tree
* @return array|false
*/
protected function getDimensionInfoFromMetaTree( $metatree ) {
if ( !$metatree ) {
return false;
}
$dimsByPage = [];
if ( !isset( $metatree['data'] ) || !$metatree['data'] ) {
return false;
}
foreach ( $metatree['data']['pages'] as $page ) {
if ( !$page ) {
$dimsByPage[] = false;
} else {
$dimsByPage[] = [
'width' => (int)$page['width'],
'height' => (int)$page['height'],
];
}
}
return [
'pageCount' => count( $metatree['data']['pages'] ),
'dimensionsByPage' => $dimsByPage
];
}
/**
* @param File $image
* @param int $page Page number to get information for
* @return string|false Page text or false when no text found.
*/
public function getPageText( File $image, $page ) {
$tree = $this->getMetaTree( $image, true );
if ( !$tree ) {
return false;
}
if ( isset( $tree['text'] ) && isset( $tree['text'][$page - 1] ) ) {
return $tree['text'][$page - 1];
}
return false;
}
public function useSplitMetadata() {
return true;
}
}

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text/x-php
Expires
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DjVuHandler.php (10 KB)

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