image.php

php 开发的内容管理系统

<?php
/**
 * @package MediaWiki
 */

/**
 * NOTE FOR WINDOWS USERS:
 * To enable EXIF functions, add the folloing lines to the
 * "Windows extensions" section of php.ini:
 *
 * extension=extensions/php_mbstring.dll
 * extension=extensions/php_exif.dll
 */

/**
 * Bump this number when serialized cache records may be incompatible.
 */
define( 'MW_IMAGE_VERSION', 1 );

/**
 * Class to represent an image
 *
 * Provides methods to retrieve paths (physical, logical, URL),
 * to generate thumbnails or for uploading.
 * @package MediaWiki
 */
class Image
{
	/**#@+
	 * @private
	 */
	var	$name,          # name of the image (constructor)
		$imagePath,     # Path of the image (loadFromXxx)
		$url,           # Image URL (accessor)
		$title,         # Title object for this image (constructor)
		$fileExists,    # does the image file exist on disk? (loadFromXxx)
		$fromSharedDirectory, # load this image from $wgSharedUploadDirectory (loadFromXxx)
		$historyLine,	# Number of line to return by nextHistoryLine() (constructor)
		$historyRes,	# result of the query for the image's history (nextHistoryLine)
		$width,         # \
		$height,        #  |
		$bits,          #   --- returned by getimagesize (loadFromXxx)
		$attr,          # /
		$type,          # MEDIATYPE_xxx (bitmap, drawing, audio...)
		$mime,          # MIME type, determined by MimeMagic::guessMimeType
		$size,          # Size in bytes (loadFromXxx)
		$metadata,      # Metadata
		$dataLoaded,    # Whether or not all this has been loaded from the database (loadFromXxx)
		$lastError;     # Error string associated with a thumbnail display error


	/**#@-*/

	/**
	 * Create an Image object from an image name
	 *
	 * @param string $name name of the image, used to create a title object using Title::makeTitleSafe
	 * @public
	 */
	function newFromName( $name ) {
		$title = Title::makeTitleSafe( NS_IMAGE, $name );
		if ( is_object( $title ) ) {
			return new Image( $title );
		} else {
			return NULL;
		}
	}

	/**
	 * Obsolete factory function, use constructor
	 * @deprecated
	 */
	function newFromTitle( $title ) {
		return new Image( $title );
	}

	function Image( $title ) {
		if( !is_object( $title ) ) {
			throw new MWException( 'Image constructor given bogus title.' );
		}
		$this->title =& $title;
		$this->name = $title->getDBkey();
		$this->metadata = serialize ( array() ) ;

		$n = strrpos( $this->name, '.' );
		$this->extension = Image::normalizeExtension( $n ?
			substr( $this->name, $n + 1 ) : '' );
		$this->historyLine = 0;

		$this->dataLoaded = false;
	}

	
	/**
	 * Normalize a file extension to the common form, and ensure it's clean.
	 * Extensions with non-alphanumeric characters will be discarded.
	 *
	 * @param $ext string (without the .)
	 * @return string
	 */
	static function normalizeExtension( $ext ) {
		$lower = strtolower( $ext );
		$squish = array(
			'htm' => 'html',
			'jpeg' => 'jpg',
			'mpeg' => 'mpg',
			'tiff' => 'tif' );
		if( isset( $squish[$lower] ) ) {
			return $squish[$lower];
		} elseif( preg_match( '/^[0-9a-z]+$/', $lower ) ) {
			return $lower;
		} else {
			return '';
		}
	}
	
	/**
	 * Get the memcached keys
	 * Returns an array, first element is the local cache key, second is the shared cache key, if there is one
	 */
	function getCacheKeys( ) {
		global $wgDBname, $wgUseSharedUploads, $wgSharedUploadDBname, $wgCacheSharedUploads;

		$hashedName = md5($this->name);
		$keys = array( "$wgDBname:Image:$hashedName" );
		if ( $wgUseSharedUploads && $wgSharedUploadDBname && $wgCacheSharedUploads ) {
			$keys[] = "$wgSharedUploadDBname:Image:$hashedName";
		}
		return $keys;
	}

	/**
	 * Try to load image metadata from memcached. Returns true on success.
	 */
	function loadFromCache() {
		global $wgUseSharedUploads, $wgMemc;
		wfProfileIn( __METHOD__ );
		$this->dataLoaded = false;
		$keys = $this->getCacheKeys();
		$cachedValues = $wgMemc->get( $keys[0] );

		// Check if the key existed and belongs to this version of MediaWiki
		if (!empty($cachedValues) && is_array($cachedValues)
		  && isset($cachedValues['version']) && ( $cachedValues['version'] == MW_IMAGE_VERSION )
		  && $cachedValues['fileExists'] && isset( $cachedValues['mime'] ) && isset( $cachedValues['metadata'] ) )
		{
			if ( $wgUseSharedUploads && $cachedValues['fromShared']) {
				# if this is shared file, we need to check if image
				# in shared repository has not changed
				if ( isset( $keys[1] ) ) {
					$commonsCachedValues = $wgMemc->get( $keys[1] );
					if (!empty($commonsCachedValues) && is_array($commonsCachedValues)
					  && isset($commonsCachedValues['version'])
					  && ( $commonsCachedValues['version'] == MW_IMAGE_VERSION )
					  && isset($commonsCachedValues['mime'])) {
						wfDebug( "Pulling image metadata from shared repository cache\n" );
						$this->name = $commonsCachedValues['name'];
						$this->imagePath = $commonsCachedValues['imagePath'];
						$this->fileExists = $commonsCachedValues['fileExists'];
						$this->width = $commonsCachedValues['width'];
						$this->height = $commonsCachedValues['height'];
						$this->bits = $commonsCachedValues['bits'];
						$this->type = $commonsCachedValues['type'];
						$this->mime = $commonsCachedValues['mime'];
						$this->metadata = $commonsCachedValues['metadata'];
						$this->size = $commonsCachedValues['size'];
						$this->fromSharedDirectory = true;
						$this->dataLoaded = true;
						$this->imagePath = $this->getFullPath(true);
					}
				}
			} else {
				wfDebug( "Pulling image metadata from local cache\n" );
				$this->name = $cachedValues['name'];
				$this->imagePath = $cachedValues['imagePath'];
				$this->fileExists = $cachedValues['fileExists'];
				$this->width = $cachedValues['width'];
				$this->height = $cachedValues['height'];
				$this->bits = $cachedValues['bits'];
				$this->type = $cachedValues['type'];
				$this->mime = $cachedValues['mime'];
				$this->metadata = $cachedValues['metadata'];
				$this->size = $cachedValues['size'];
				$this->fromSharedDirectory = false;
				$this->dataLoaded = true;
				$this->imagePath = $this->getFullPath();
			}
		}
		if ( $this->dataLoaded ) {
			wfIncrStats( 'image_cache_hit' );
		} else {
			wfIncrStats( 'image_cache_miss' );
		}

		wfProfileOut( __METHOD__ );
		return $this->dataLoaded;
	}

	/**
	 * Save the image metadata to memcached
	 */
	function saveToCache() {
		global $wgMemc;
		$this->load();
		$keys = $this->getCacheKeys();
		if ( $this->fileExists ) {
			// We can't cache negative metadata for non-existent files,
			// because if the file later appears in commons, the local
			// keys won't be purged.
			$cachedValues = array(
				'version'    => MW_IMAGE_VERSION,
				'name'       => $this->name,
				'imagePath'  => $this->imagePath,
				'fileExists' => $this->fileExists,
				'fromShared' => $this->fromSharedDirectory,
				'width'      => $this->width,
				'height'     => $this->height,
				'bits'       => $this->bits,
				'type'       => $this->type,
				'mime'       => $this->mime,
				'metadata'   => $this->metadata,
				'size'       => $this->size );

			$wgMemc->set( $keys[0], $cachedValues, 60 * 60 * 24 * 7 ); // A week
		} else {
			// However we should clear them, so they aren't leftover
			// if we've deleted the file.
			$wgMemc->delete( $keys[0] );
		}
	}

	/**
	 * Load metadata from the file itself
	 */
	function loadFromFile() {
		global $wgUseSharedUploads, $wgSharedUploadDirectory, $wgContLang, $wgShowEXIF;
		wfProfileIn( __METHOD__ );
		$this->imagePath = $this->getFullPath();
		$this->fileExists = file_exists( $this->imagePath );
		$this->fromSharedDirectory = false;
		$gis = array();

		if (!$this->fileExists) wfDebug(__METHOD__.': '.$this->imagePath." not found locally!\n");

		# If the file is not found, and a shared upload directory is used, look for it there.
		if (!$this->fileExists && $wgUseSharedUploads && $wgSharedUploadDirectory) {
			# In case we're on a wgCapitalLinks=false wiki, we
			# capitalize the first letter of the filename before
			# looking it up in the shared repository.
			$sharedImage = Image::newFromName( $wgContLang->ucfirst($this->name) );
			$this->fileExists = $sharedImage && file_exists( $sharedImage->getFullPath(true) );
			if ( $this->fileExists ) {
				$this->name = $sharedImage->name;
				$this->imagePath = $this->getFullPath(true);
				$this->fromSharedDirectory = true;
			}
		}


		if ( $this->fileExists ) {
			$magic=& wfGetMimeMagic();

			$this->mime = $magic->guessMimeType($this->imagePath,true);
			$this->type = $magic->getMediaType($this->imagePath,$this->mime);

			# Get size in bytes
			$this->size = filesize( $this->imagePath );

			$magic=& wfGetMimeMagic();

			# Height and width
			wfSuppressWarnings();
			if( $this->mime == 'image/svg' ) {
				$gis = wfGetSVGsize( $this->imagePath );
			} elseif( $this->mime == 'image/vnd.djvu' ) {
				$deja = new DjVuImage( $this->imagePath );
				$gis = $deja->getImageSize();
			} elseif ( !$magic->isPHPImageType( $this->mime ) ) {
				# Don't try to get the width and height of sound and video files, that's bad for performance
				$gis = false;
			} else {
				$gis = getimagesize( $this->imagePath );
			}
			wfRestoreWarnings();

			wfDebug(__METHOD__.': '.$this->imagePath." loaded, ".$this->size." bytes, ".$this->mime.".\n");
		}
		else {
			$this->mime = NULL;
			$this->type = MEDIATYPE_UNKNOWN;
			wfDebug(__METHOD__.': '.$this->imagePath." NOT FOUND!\n");
		}

		if( $gis ) {
			$this->width = $gis[0];
			$this->height = $gis[1];
		} else {
			$this->width = 0;
			$this->height = 0;
		}

		#NOTE: $gis[2] contains a code for the image type. This is no longer used.

		#NOTE: we have to set this flag early to avoid load() to be called
		# be some of the functions below. This may lead to recursion or other bad things!
		# as ther's only one thread of execution, this should be safe anyway.
		$this->dataLoaded = true;


		$this->metadata = serialize( $this->retrieveExifData( $this->imagePath ) );

		if ( isset( $gis['bits'] ) )  $this->bits = $gis['bits'];
		else $this->bits = 0;

		wfProfileOut( __METHOD__ );
	}

	/**
	 * Load image metadata from the DB
	 */
	function loadFromDB() {
		global $wgUseSharedUploads, $wgSharedUploadDBname, $wgSharedUploadDBprefix, $wgContLang;
		wfProfileIn( __METHOD__ );

		$dbr =& wfGetDB( DB_SLAVE );

		$this->checkDBSchema($dbr);

		$row = $dbr->selectRow( 'image',
			array( 'img_size', 'img_width', 'img_height', 'img_bits',
			       'img_media_type', 'img_major_mime', 'img_minor_mime', 'img_metadata' ),
			array( 'img_name' => $this->name ), __METHOD__ );
		if ( $row ) {
			$this->fromSharedDirectory = false;
			$this->fileExists = true;
			$this->loadFromRow( $row );
			$this->imagePath = $this->getFullPath();
			// Check for rows from a previous schema, quietly upgrade them
			if ( is_null($this->type) ) {
				$this->upgradeRow();
			}
		} elseif ( $wgUseSharedUploads && $wgSharedUploadDBname ) {
			# In case we're on a wgCapitalLinks=false wiki, we
			# capitalize the first letter of the filename before
			# looking it up in the shared repository.
			$name = $wgContLang->ucfirst($this->name);
			$dbc =& wfGetDB( DB_SLAVE, 'commons' );

			$row = $dbc->selectRow( "`$wgSharedUploadDBname`.{$wgSharedUploadDBprefix}image",
				array(
					'img_size', 'img_width', 'img_height', 'img_bits',
					'img_media_type', 'img_major_mime', 'img_minor_mime', 'img_metadata' ),
				array( 'img_name' => $name ), __METHOD__ );
			if ( $row ) {
				$this->fromSharedDirectory = true;
				$this->fileExists = true;
				$this->imagePath = $this->getFullPath(true);
				$this->name = $name;
				$this->loadFromRow( $row );

				// Check for rows from a previous schema, quietly upgrade them
				if ( is_null($this->type) ) {
					$this->upgradeRow();
				}
			}
		}

		if ( !$row ) {
			$this->size = 0;
			$this->width = 0;
			$this->height = 0;
			$this->bits = 0;
			$this->type = 0;
			$this->fileExists = false;
			$this->fromSharedDirectory = false;
			$this->metadata = serialize ( array() ) ;
		}

		# Unconditionally set loaded=true, we don't want the accessors constantly rechecking
		$this->dataLoaded = true;
		wfProfileOut( __METHOD__ );
	}

	/*
	 * Load image metadata from a DB result row
	 */
	function loadFromRow( &$row ) {
		$this->size = $row->img_size;
		$this->width = $row->img_width;
		$this->height = $row->img_height;
		$this->bits = $row->img_bits;
		$this->type = $row->img_media_type;

		$major= $row->img_major_mime;
		$minor= $row->img_minor_mime;

		if (!$major) $this->mime = "unknown/unknown";
		else {
			if (!$minor) $minor= "unknown";
			$this->mime = $major.'/'.$minor;
		}

		$this->metadata = $row->img_metadata;
		if ( $this->metadata == "" ) $this->metadata = serialize ( array() ) ;

		$this->dataLoaded = true;
	}

	/**
	 * Load image metadata from cache or DB, unless already loaded
	 */
	function load() {
		global $wgSharedUploadDBname, $wgUseSharedUploads;
		if ( !$this->dataLoaded ) {
			if ( !$this->loadFromCache() ) {
				$this->loadFromDB();
				if ( !$wgSharedUploadDBname && $wgUseSharedUploads ) {
					$this->loadFromFile();
				} elseif ( $this->fileExists ) {
					$this->saveToCache();
				}
			}
			$this->dataLoaded = true;
		}
	}

	/**
	 * Metadata was loaded from the database, but the row had a marker indicating it needs to be
	 * upgraded from the 1.4 schema, which had no width, height, bits or type. Upgrade the row.
	 */
	function upgradeRow() {
		global $wgDBname, $wgSharedUploadDBname;
		wfProfileIn( __METHOD__ );

		$this->loadFromFile();

		if ( $this->fromSharedDirectory ) {
			if ( !$wgSharedUploadDBname ) {
				wfProfileOut( __METHOD__ );
				return;
			}

			// Write to the other DB using selectDB, not database selectors
			// This avoids breaking replication in MySQL