nextcloud / server

lib/private/Preview/Movie.php

Indentation +58 added lines, -58 removed lines

@@ -29,73 +29,73 @@
 use OCP\IImage;
 
 class Movie extends ProviderV2 {
-	public static $avconvBinary;
-	public static $ffmpegBinary;
+    public static $avconvBinary;
+    public static $ffmpegBinary;
 
-	/**
-	 * {@inheritDoc}
-	 */
-	public function getMimeType(): string {
-		return '/video\/.*/';
-	}
+    /**
+     * {@inheritDoc}
+     */
+    public function getMimeType(): string {
+        return '/video\/.*/';
+    }
 
-	/**
-	 * {@inheritDoc}
-	 */
-	public function getThumbnail(File $file, int $maxX, int $maxY): ?IImage {
-		// TODO: use proc_open() and stream the source file ?
+    /**
+     * {@inheritDoc}
+     */
+    public function getThumbnail(File $file, int $maxX, int $maxY): ?IImage {
+        // TODO: use proc_open() and stream the source file ?
 
-		$absPath = $this->getLocalFile($file, 5242880); // only use the first 5MB
+        $absPath = $this->getLocalFile($file, 5242880); // only use the first 5MB
 
-		$result = $this->generateThumbNail($maxX, $maxY, $absPath, 5);
-		if ($result === false) {
-			$result = $this->generateThumbNail($maxX, $maxY, $absPath, 1);
-			if ($result === false) {
-				$result = $this->generateThumbNail($maxX, $maxY, $absPath, 0);
-			}
-		}
+        $result = $this->generateThumbNail($maxX, $maxY, $absPath, 5);
+        if ($result === false) {
+            $result = $this->generateThumbNail($maxX, $maxY, $absPath, 1);
+            if ($result === false) {
+                $result = $this->generateThumbNail($maxX, $maxY, $absPath, 0);
+            }
+        }
 
-		$this->cleanTmpFiles();
+        $this->cleanTmpFiles();
 
-		return $result;
-	}
+        return $result;
+    }
 
-	/**
-	 * @param int $maxX
-	 * @param int $maxY
-	 * @param string $absPath
-	 * @param int $second
-	 * @return null|\OCP\IImage
-	 */
-	private function generateThumbNail($maxX, $maxY, $absPath, $second): ?IImage {
-		$tmpPath = \OC::$server->getTempManager()->getTemporaryFile();
+    /**
+     * @param int $maxX
+     * @param int $maxY
+     * @param string $absPath
+     * @param int $second
+     * @return null|\OCP\IImage
+     */
+    private function generateThumbNail($maxX, $maxY, $absPath, $second): ?IImage {
+        $tmpPath = \OC::$server->getTempManager()->getTemporaryFile();
 
-		if (self::$avconvBinary) {
-			$cmd = self::$avconvBinary . ' -y -ss ' . escapeshellarg($second) .
-				' -i ' . escapeshellarg($absPath) .
-				' -an -f mjpeg -vframes 1 -vsync 1 ' . escapeshellarg($tmpPath) .
-				' > /dev/null 2>&1';
-		} else {
-			$cmd = self::$ffmpegBinary . ' -y -ss ' . escapeshellarg($second) .
-				' -i ' . escapeshellarg($absPath) .
-				' -f mjpeg -vframes 1' .
-				' ' . escapeshellarg($tmpPath) .
-				' > /dev/null 2>&1';
-		}
+        if (self::$avconvBinary) {
+            $cmd = self::$avconvBinary . ' -y -ss ' . escapeshellarg($second) .
+                ' -i ' . escapeshellarg($absPath) .
+                ' -an -f mjpeg -vframes 1 -vsync 1 ' . escapeshellarg($tmpPath) .
+                ' > /dev/null 2>&1';
+        } else {
+            $cmd = self::$ffmpegBinary . ' -y -ss ' . escapeshellarg($second) .
+                ' -i ' . escapeshellarg($absPath) .
+                ' -f mjpeg -vframes 1' .
+                ' ' . escapeshellarg($tmpPath) .
+                ' > /dev/null 2>&1';
+        }
 
-		exec($cmd, $output, $returnCode);
+        exec($cmd, $output, $returnCode);
 
-		if ($returnCode === 0) {
-			$image = new \OC_Image();
-			$image->loadFromFile($tmpPath);
-			unlink($tmpPath);
-			if ($image->valid()) {
-				$image->scaleDownToFit($maxX, $maxY);
+        if ($returnCode === 0) {
+            $image = new \OC_Image();
+            $image->loadFromFile($tmpPath);
+            unlink($tmpPath);
+            if ($image->valid()) {
+                $image->scaleDownToFit($maxX, $maxY);
 
-				return $image;
-			}
-		}
-		unlink($tmpPath);
-		return null;
-	}
+                return $image;
+            }
+        }
+        unlink($tmpPath);
+        return null;
+    }
 }

lib/private/PreviewManager.php

Indentation +387 added lines, -387 removed lines

@@ -39,391 +39,391 @@
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 class PreviewManager implements IPreview {
-	/** @var IConfig */
-	protected $config;
-
-	/** @var IRootFolder */
-	protected $rootFolder;
-
-	/** @var IAppData */
-	protected $appData;
-
-	/** @var EventDispatcherInterface */
-	protected $eventDispatcher;
-
-	/** @var Generator */
-	private $generator;
-
-	/** @var bool */
-	protected $providerListDirty = false;
-
-	/** @var bool */
-	protected $registeredCoreProviders = false;
-
-	/** @var array */
-	protected $providers = [];
-
-	/** @var array mime type => support status */
-	protected $mimeTypeSupportMap = [];
-
-	/** @var array */
-	protected $defaultProviders;
-
-	/** @var string */
-	protected $userId;
-
-	/**
-	 * PreviewManager constructor.
-	 *
-	 * @param IConfig $config
-	 * @param IRootFolder $rootFolder
-	 * @param IAppData $appData
-	 * @param EventDispatcherInterface $eventDispatcher
-	 * @param string $userId
-	 */
-	public function __construct(IConfig $config,
-								IRootFolder $rootFolder,
-								IAppData $appData,
-								EventDispatcherInterface $eventDispatcher,
-								$userId) {
-		$this->config = $config;
-		$this->rootFolder = $rootFolder;
-		$this->appData = $appData;
-		$this->eventDispatcher = $eventDispatcher;
-		$this->userId = $userId;
-	}
-
-	/**
-	 * In order to improve lazy loading a closure can be registered which will be
-	 * called in case preview providers are actually requested
-	 *
-	 * $callable has to return an instance of \OCP\Preview\IProvider or \OCP\Preview\IProviderV2
-	 *
-	 * @param string $mimeTypeRegex Regex with the mime types that are supported by this provider
-	 * @param \Closure $callable
-	 * @return void
-	 */
-	public function registerProvider($mimeTypeRegex, \Closure $callable) {
-		if (!$this->config->getSystemValue('enable_previews', true)) {
-			return;
-		}
-
-		if (!isset($this->providers[$mimeTypeRegex])) {
-			$this->providers[$mimeTypeRegex] = [];
-		}
-		$this->providers[$mimeTypeRegex][] = $callable;
-		$this->providerListDirty = true;
-	}
-
-	/**
-	 * Get all providers
-	 * @return array
-	 */
-	public function getProviders() {
-		if (!$this->config->getSystemValue('enable_previews', true)) {
-			return [];
-		}
-
-		$this->registerCoreProviders();
-		if ($this->providerListDirty) {
-			$keys = array_map('strlen', array_keys($this->providers));
-			array_multisort($keys, SORT_DESC, $this->providers);
-			$this->providerListDirty = false;
-		}
-
-		return $this->providers;
-	}
-
-	/**
-	 * Does the manager have any providers
-	 * @return bool
-	 */
-	public function hasProviders() {
-		$this->registerCoreProviders();
-		return !empty($this->providers);
-	}
-
-	/**
-	 * return a preview of a file
-	 *
-	 * @param string $file The path to the file where you want a thumbnail from
-	 * @param int $maxX The maximum X size of the thumbnail. It can be smaller depending on the shape of the image
-	 * @param int $maxY The maximum Y size of the thumbnail. It can be smaller depending on the shape of the image
-	 * @param boolean $scaleUp Scale smaller images up to the thumbnail size or not. Might look ugly
-	 * @return \OCP\IImage
-	 * @deprecated 11 Use getPreview
-	 */
-	public function createPreview($file, $maxX = 100, $maxY = 75, $scaleUp = false) {
-		try {
-			$userRoot = $this->rootFolder->getUserFolder($this->userId)->getParent();
-			$node = $userRoot->get($file);
-			if (!($file instanceof File)) {
-				throw new NotFoundException();
-			}
-
-			$preview = $this->getPreview($node, $maxX, $maxY);
-		} catch (\Exception $e) {
-			return new \OC_Image();
-		}
-
-		$previewImage = new \OC_Image();
-		$previewImage->loadFromData($preview->getContent());
-		return $previewImage;
-	}
-
-	/**
-	 * Returns a preview of a file
-	 *
-	 * The cache is searched first and if nothing usable was found then a preview is
-	 * generated by one of the providers
-	 *
-	 * @param File $file
-	 * @param int $width
-	 * @param int $height
-	 * @param bool $crop
-	 * @param string $mode
-	 * @param string $mimeType
-	 * @return ISimpleFile
-	 * @throws NotFoundException
-	 * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid)
-	 * @since 11.0.0 - \InvalidArgumentException was added in 12.0.0
-	 */
-	public function getPreview(File $file, $width = -1, $height = -1, $crop = false, $mode = IPreview::MODE_FILL, $mimeType = null) {
-		if ($this->generator === null) {
-			$this->generator = new Generator(
-				$this->config,
-				$this,
-				$this->appData,
-				new GeneratorHelper(
-					$this->rootFolder,
-					$this->config
-				),
-				$this->eventDispatcher
-			);
-		}
-
-		return $this->generator->getPreview($file, $width, $height, $crop, $mode, $mimeType);
-	}
-
-	/**
-	 * returns true if the passed mime type is supported
-	 *
-	 * @param string $mimeType
-	 * @return boolean
-	 */
-	public function isMimeSupported($mimeType = '*') {
-		if (!$this->config->getSystemValue('enable_previews', true)) {
-			return false;
-		}
-
-		if (isset($this->mimeTypeSupportMap[$mimeType])) {
-			return $this->mimeTypeSupportMap[$mimeType];
-		}
-
-		$this->registerCoreProviders();
-		$providerMimeTypes = array_keys($this->providers);
-		foreach ($providerMimeTypes as $supportedMimeType) {
-			if (preg_match($supportedMimeType, $mimeType)) {
-				$this->mimeTypeSupportMap[$mimeType] = true;
-				return true;
-			}
-		}
-		$this->mimeTypeSupportMap[$mimeType] = false;
-		return false;
-	}
-
-	/**
-	 * Check if a preview can be generated for a file
-	 *
-	 * @param \OCP\Files\FileInfo $file
-	 * @return bool
-	 */
-	public function isAvailable(\OCP\Files\FileInfo $file) {
-		if (!$this->config->getSystemValue('enable_previews', true)) {
-			return false;
-		}
-
-		$this->registerCoreProviders();
-		if (!$this->isMimeSupported($file->getMimetype())) {
-			return false;
-		}
-
-		$mount = $file->getMountPoint();
-		if ($mount and !$mount->getOption('previews', true)){
-			return false;
-		}
-
-		foreach ($this->providers as $supportedMimeType => $providers) {
-			if (preg_match($supportedMimeType, $file->getMimetype())) {
-				foreach ($providers as $closure) {
-					$provider = $closure();
-					if (!($provider instanceof IProvider)) {
-						continue;
-					}
-
-					/** @var $provider IProvider */
-					if ($provider->isAvailable($file)) {
-						return true;
-					}
-				}
-			}
-		}
-		return false;
-	}
-
-	/**
-	 * List of enabled default providers
-	 *
-	 * The following providers are enabled by default:
-	 *  - OC\Preview\PNG
-	 *  - OC\Preview\JPEG
-	 *  - OC\Preview\GIF
-	 *  - OC\Preview\BMP
-	 *  - OC\Preview\HEIC
-	 *  - OC\Preview\XBitmap
-	 *  - OC\Preview\MarkDown
-	 *  - OC\Preview\MP3
-	 *  - OC\Preview\TXT
-	 *
-	 * The following providers are disabled by default due to performance or privacy concerns:
-	 *  - OC\Preview\Font
-	 *  - OC\Preview\Illustrator
-	 *  - OC\Preview\Movie
-	 *  - OC\Preview\MSOfficeDoc
-	 *  - OC\Preview\MSOffice2003
-	 *  - OC\Preview\MSOffice2007
-	 *  - OC\Preview\OpenDocument
-	 *  - OC\Preview\PDF
-	 *  - OC\Preview\Photoshop
-	 *  - OC\Preview\Postscript
-	 *  - OC\Preview\StarOffice
-	 *  - OC\Preview\SVG
-	 *  - OC\Preview\TIFF
-	 *
-	 * @return array
-	 */
-	protected function getEnabledDefaultProvider() {
-		if ($this->defaultProviders !== null) {
-			return $this->defaultProviders;
-		}
-
-		$imageProviders = [
-			Preview\PNG::class,
-			Preview\JPEG::class,
-			Preview\GIF::class,
-			Preview\BMP::class,
-			Preview\HEIC::class,
-			Preview\XBitmap::class
-		];
-
-		$this->defaultProviders = $this->config->getSystemValue('enabledPreviewProviders', array_merge([
-			Preview\MarkDown::class,
-			Preview\MP3::class,
-			Preview\TXT::class,
-		], $imageProviders));
-
-		if (in_array(Preview\Image::class, $this->defaultProviders)) {
-			$this->defaultProviders = array_merge($this->defaultProviders, $imageProviders);
-		}
-		$this->defaultProviders = array_unique($this->defaultProviders);
-		return $this->defaultProviders;
-	}
-
-	/**
-	 * Register the default providers (if enabled)
-	 *
-	 * @param string $class
-	 * @param string $mimeType
-	 */
-	protected function registerCoreProvider($class, $mimeType, $options = []) {
-		if (in_array(trim($class, '\\'), $this->getEnabledDefaultProvider())) {
-			$this->registerProvider($mimeType, function () use ($class, $options) {
-				return new $class($options);
-			});
-		}
-	}
-
-	/**
-	 * Register the default providers (if enabled)
-	 */
-	protected function registerCoreProviders() {
-		if ($this->registeredCoreProviders) {
-			return;
-		}
-		$this->registeredCoreProviders = true;
-
-		$this->registerCoreProvider(Preview\TXT::class, '/text\/plain/');
-		$this->registerCoreProvider(Preview\MarkDown::class, '/text\/(x-)?markdown/');
-		$this->registerCoreProvider(Preview\PNG::class, '/image\/png/');
-		$this->registerCoreProvider(Preview\JPEG::class, '/image\/jpeg/');
-		$this->registerCoreProvider(Preview\GIF::class, '/image\/gif/');
-		$this->registerCoreProvider(Preview\BMP::class, '/image\/bmp/');
-		$this->registerCoreProvider(Preview\XBitmap::class, '/image\/x-xbitmap/');
-		$this->registerCoreProvider(Preview\MP3::class, '/audio\/mpeg/');
-
-		// SVG, Office and Bitmap require imagick
-		if (extension_loaded('imagick')) {
-			$checkImagick = new \Imagick();
-
-			$imagickProviders = [
-				'SVG'	=> ['mimetype' => '/image\/svg\+xml/', 'class' => Preview\SVG::class],
-				'TIFF'	=> ['mimetype' => '/image\/tiff/', 'class' => Preview\TIFF::class],
-				'PDF'	=> ['mimetype' => '/application\/pdf/', 'class' => Preview\PDF::class],
-				'AI'	=> ['mimetype' => '/application\/illustrator/', 'class' => Preview\Illustrator::class],
-				'PSD'	=> ['mimetype' => '/application\/x-photoshop/', 'class' => Preview\Photoshop::class],
-				'EPS'	=> ['mimetype' => '/application\/postscript/', 'class' => Preview\Postscript::class],
-				'TTF'	=> ['mimetype' => '/application\/(?:font-sfnt|x-font$)/', 'class' => Preview\Font::class],
-				'HEIC'  => ['mimetype' => '/image\/hei(f|c)/', 'class' => Preview\HEIC::class],
-			];
-
-			foreach ($imagickProviders as $queryFormat => $provider) {
-				$class = $provider['class'];
-				if (!in_array(trim($class, '\\'), $this->getEnabledDefaultProvider())) {
-					continue;
-				}
-
-				if (count($checkImagick->queryFormats($queryFormat)) === 1) {
-					$this->registerCoreProvider($class, $provider['mimetype']);
-				}
-			}
-
-			if (count($checkImagick->queryFormats('PDF')) === 1) {
-				if (\OC_Helper::is_function_enabled('shell_exec')) {
-					$officeFound = is_string($this->config->getSystemValue('preview_libreoffice_path', null));
-
-					if (!$officeFound) {
-						//let's see if there is libreoffice or openoffice on this machine
-						$whichLibreOffice = shell_exec('command -v libreoffice');
-						$officeFound = !empty($whichLibreOffice);
-						if (!$officeFound) {
-							$whichOpenOffice = shell_exec('command -v openoffice');
-							$officeFound = !empty($whichOpenOffice);
-						}
-					}
-
-					if ($officeFound) {
-						$this->registerCoreProvider(Preview\MSOfficeDoc::class, '/application\/msword/');
-						$this->registerCoreProvider(Preview\MSOffice2003::class, '/application\/vnd.ms-.*/');
-						$this->registerCoreProvider(Preview\MSOffice2007::class, '/application\/vnd.openxmlformats-officedocument.*/');
-						$this->registerCoreProvider(Preview\OpenDocument::class, '/application\/vnd.oasis.opendocument.*/');
-						$this->registerCoreProvider(Preview\StarOffice::class, '/application\/vnd.sun.xml.*/');
-					}
-				}
-			}
-		}
-
-		// Video requires avconv or ffmpeg
-		if (in_array(Preview\Movie::class, $this->getEnabledDefaultProvider())) {
-			$avconvBinary = \OC_Helper::findBinaryPath('avconv');
-			$ffmpegBinary = $avconvBinary ? null : \OC_Helper::findBinaryPath('ffmpeg');
-
-			if ($avconvBinary || $ffmpegBinary) {
-				// FIXME // a bit hacky but didn't want to use subclasses
-				\OC\Preview\Movie::$avconvBinary = $avconvBinary;
-				\OC\Preview\Movie::$ffmpegBinary = $ffmpegBinary;
-
-				$this->registerCoreProvider(Preview\Movie::class, '/video\/.*/');
-			}
-		}
-	}
+    /** @var IConfig */
+    protected $config;
+
+    /** @var IRootFolder */
+    protected $rootFolder;
+
+    /** @var IAppData */
+    protected $appData;
+
+    /** @var EventDispatcherInterface */
+    protected $eventDispatcher;
+
+    /** @var Generator */
+    private $generator;
+
+    /** @var bool */
+    protected $providerListDirty = false;
+
+    /** @var bool */
+    protected $registeredCoreProviders = false;
+
+    /** @var array */
+    protected $providers = [];
+
+    /** @var array mime type => support status */
+    protected $mimeTypeSupportMap = [];
+
+    /** @var array */
+    protected $defaultProviders;
+
+    /** @var string */
+    protected $userId;
+
+    /**
+     * PreviewManager constructor.
+     *
+     * @param IConfig $config
+     * @param IRootFolder $rootFolder
+     * @param IAppData $appData
+     * @param EventDispatcherInterface $eventDispatcher
+     * @param string $userId
+     */
+    public function __construct(IConfig $config,
+                                IRootFolder $rootFolder,
+                                IAppData $appData,
+                                EventDispatcherInterface $eventDispatcher,
+                                $userId) {
+        $this->config = $config;
+        $this->rootFolder = $rootFolder;
+        $this->appData = $appData;
+        $this->eventDispatcher = $eventDispatcher;
+        $this->userId = $userId;
+    }
+
+    /**
+     * In order to improve lazy loading a closure can be registered which will be
+     * called in case preview providers are actually requested
+     *
+     * $callable has to return an instance of \OCP\Preview\IProvider or \OCP\Preview\IProviderV2
+     *
+     * @param string $mimeTypeRegex Regex with the mime types that are supported by this provider
+     * @param \Closure $callable
+     * @return void
+     */
+    public function registerProvider($mimeTypeRegex, \Closure $callable) {
+        if (!$this->config->getSystemValue('enable_previews', true)) {
+            return;
+        }
+
+        if (!isset($this->providers[$mimeTypeRegex])) {
+            $this->providers[$mimeTypeRegex] = [];
+        }
+        $this->providers[$mimeTypeRegex][] = $callable;
+        $this->providerListDirty = true;
+    }
+
+    /**
+     * Get all providers
+     * @return array
+     */
+    public function getProviders() {
+        if (!$this->config->getSystemValue('enable_previews', true)) {
+            return [];
+        }
+
+        $this->registerCoreProviders();
+        if ($this->providerListDirty) {
+            $keys = array_map('strlen', array_keys($this->providers));
+            array_multisort($keys, SORT_DESC, $this->providers);
+            $this->providerListDirty = false;
+        }
+
+        return $this->providers;
+    }
+
+    /**
+     * Does the manager have any providers
+     * @return bool
+     */
+    public function hasProviders() {
+        $this->registerCoreProviders();
+        return !empty($this->providers);
+    }
+
+    /**
+     * return a preview of a file
+     *
+     * @param string $file The path to the file where you want a thumbnail from
+     * @param int $maxX The maximum X size of the thumbnail. It can be smaller depending on the shape of the image
+     * @param int $maxY The maximum Y size of the thumbnail. It can be smaller depending on the shape of the image
+     * @param boolean $scaleUp Scale smaller images up to the thumbnail size or not. Might look ugly
+     * @return \OCP\IImage
+     * @deprecated 11 Use getPreview
+     */
+    public function createPreview($file, $maxX = 100, $maxY = 75, $scaleUp = false) {
+        try {
+            $userRoot = $this->rootFolder->getUserFolder($this->userId)->getParent();
+            $node = $userRoot->get($file);
+            if (!($file instanceof File)) {
+                throw new NotFoundException();
+            }
+
+            $preview = $this->getPreview($node, $maxX, $maxY);
+        } catch (\Exception $e) {
+            return new \OC_Image();
+        }
+
+        $previewImage = new \OC_Image();
+        $previewImage->loadFromData($preview->getContent());
+        return $previewImage;
+    }
+
+    /**
+     * Returns a preview of a file
+     *
+     * The cache is searched first and if nothing usable was found then a preview is
+     * generated by one of the providers
+     *
+     * @param File $file
+     * @param int $width
+     * @param int $height
+     * @param bool $crop
+     * @param string $mode
+     * @param string $mimeType
+     * @return ISimpleFile
+     * @throws NotFoundException
+     * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid)
+     * @since 11.0.0 - \InvalidArgumentException was added in 12.0.0
+     */
+    public function getPreview(File $file, $width = -1, $height = -1, $crop = false, $mode = IPreview::MODE_FILL, $mimeType = null) {
+        if ($this->generator === null) {
+            $this->generator = new Generator(
+                $this->config,
+                $this,
+                $this->appData,
+                new GeneratorHelper(
+                    $this->rootFolder,
+                    $this->config
+                ),
+                $this->eventDispatcher
+            );
+        }
+
+        return $this->generator->getPreview($file, $width, $height, $crop, $mode, $mimeType);
+    }
+
+    /**
+     * returns true if the passed mime type is supported
+     *
+     * @param string $mimeType
+     * @return boolean
+     */
+    public function isMimeSupported($mimeType = '*') {
+        if (!$this->config->getSystemValue('enable_previews', true)) {
+            return false;
+        }
+
+        if (isset($this->mimeTypeSupportMap[$mimeType])) {
+            return $this->mimeTypeSupportMap[$mimeType];
+        }
+
+        $this->registerCoreProviders();
+        $providerMimeTypes = array_keys($this->providers);
+        foreach ($providerMimeTypes as $supportedMimeType) {
+            if (preg_match($supportedMimeType, $mimeType)) {
+                $this->mimeTypeSupportMap[$mimeType] = true;
+                return true;
+            }
+        }
+        $this->mimeTypeSupportMap[$mimeType] = false;
+        return false;
+    }
+
+    /**
+     * Check if a preview can be generated for a file
+     *
+     * @param \OCP\Files\FileInfo $file
+     * @return bool
+     */
+    public function isAvailable(\OCP\Files\FileInfo $file) {
+        if (!$this->config->getSystemValue('enable_previews', true)) {
+            return false;
+        }
+
+        $this->registerCoreProviders();
+        if (!$this->isMimeSupported($file->getMimetype())) {
+            return false;
+        }
+
+        $mount = $file->getMountPoint();
+        if ($mount and !$mount->getOption('previews', true)){
+            return false;
+        }
+
+        foreach ($this->providers as $supportedMimeType => $providers) {
+            if (preg_match($supportedMimeType, $file->getMimetype())) {
+                foreach ($providers as $closure) {
+                    $provider = $closure();
+                    if (!($provider instanceof IProvider)) {
+                        continue;
+                    }
+
+                    /** @var $provider IProvider */
+                    if ($provider->isAvailable($file)) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
+    /**
+     * List of enabled default providers
+     *
+     * The following providers are enabled by default:
+     *  - OC\Preview\PNG
+     *  - OC\Preview\JPEG
+     *  - OC\Preview\GIF
+     *  - OC\Preview\BMP
+     *  - OC\Preview\HEIC
+     *  - OC\Preview\XBitmap
+     *  - OC\Preview\MarkDown
+     *  - OC\Preview\MP3
+     *  - OC\Preview\TXT
+     *
+     * The following providers are disabled by default due to performance or privacy concerns:
+     *  - OC\Preview\Font
+     *  - OC\Preview\Illustrator
+     *  - OC\Preview\Movie
+     *  - OC\Preview\MSOfficeDoc
+     *  - OC\Preview\MSOffice2003
+     *  - OC\Preview\MSOffice2007
+     *  - OC\Preview\OpenDocument
+     *  - OC\Preview\PDF
+     *  - OC\Preview\Photoshop
+     *  - OC\Preview\Postscript
+     *  - OC\Preview\StarOffice
+     *  - OC\Preview\SVG
+     *  - OC\Preview\TIFF
+     *
+     * @return array
+     */
+    protected function getEnabledDefaultProvider() {
+        if ($this->defaultProviders !== null) {
+            return $this->defaultProviders;
+        }
+
+        $imageProviders = [
+            Preview\PNG::class,
+            Preview\JPEG::class,
+            Preview\GIF::class,
+            Preview\BMP::class,
+            Preview\HEIC::class,
+            Preview\XBitmap::class
+        ];
+
+        $this->defaultProviders = $this->config->getSystemValue('enabledPreviewProviders', array_merge([
+            Preview\MarkDown::class,
+            Preview\MP3::class,
+            Preview\TXT::class,
+        ], $imageProviders));
+
+        if (in_array(Preview\Image::class, $this->defaultProviders)) {
+            $this->defaultProviders = array_merge($this->defaultProviders, $imageProviders);
+        }
+        $this->defaultProviders = array_unique($this->defaultProviders);
+        return $this->defaultProviders;
+    }
+
+    /**
+     * Register the default providers (if enabled)
+     *
+     * @param string $class
+     * @param string $mimeType
+     */
+    protected function registerCoreProvider($class, $mimeType, $options = []) {
+        if (in_array(trim($class, '\\'), $this->getEnabledDefaultProvider())) {
+            $this->registerProvider($mimeType, function () use ($class, $options) {
+                return new $class($options);
+            });
+        }
+    }
+
+    /**
+     * Register the default providers (if enabled)
+     */
+    protected function registerCoreProviders() {
+        if ($this->registeredCoreProviders) {
+            return;
+        }
+        $this->registeredCoreProviders = true;
+
+        $this->registerCoreProvider(Preview\TXT::class, '/text\/plain/');
+        $this->registerCoreProvider(Preview\MarkDown::class, '/text\/(x-)?markdown/');
+        $this->registerCoreProvider(Preview\PNG::class, '/image\/png/');
+        $this->registerCoreProvider(Preview\JPEG::class, '/image\/jpeg/');
+        $this->registerCoreProvider(Preview\GIF::class, '/image\/gif/');
+        $this->registerCoreProvider(Preview\BMP::class, '/image\/bmp/');
+        $this->registerCoreProvider(Preview\XBitmap::class, '/image\/x-xbitmap/');
+        $this->registerCoreProvider(Preview\MP3::class, '/audio\/mpeg/');
+
+        // SVG, Office and Bitmap require imagick
+        if (extension_loaded('imagick')) {
+            $checkImagick = new \Imagick();
+
+            $imagickProviders = [
+                'SVG'	=> ['mimetype' => '/image\/svg\+xml/', 'class' => Preview\SVG::class],
+                'TIFF'	=> ['mimetype' => '/image\/tiff/', 'class' => Preview\TIFF::class],
+                'PDF'	=> ['mimetype' => '/application\/pdf/', 'class' => Preview\PDF::class],
+                'AI'	=> ['mimetype' => '/application\/illustrator/', 'class' => Preview\Illustrator::class],
+                'PSD'	=> ['mimetype' => '/application\/x-photoshop/', 'class' => Preview\Photoshop::class],
+                'EPS'	=> ['mimetype' => '/application\/postscript/', 'class' => Preview\Postscript::class],
+                'TTF'	=> ['mimetype' => '/application\/(?:font-sfnt|x-font$)/', 'class' => Preview\Font::class],
+                'HEIC'  => ['mimetype' => '/image\/hei(f|c)/', 'class' => Preview\HEIC::class],
+            ];
+
+            foreach ($imagickProviders as $queryFormat => $provider) {
+                $class = $provider['class'];
+                if (!in_array(trim($class, '\\'), $this->getEnabledDefaultProvider())) {
+                    continue;
+                }
+
+                if (count($checkImagick->queryFormats($queryFormat)) === 1) {
+                    $this->registerCoreProvider($class, $provider['mimetype']);
+                }
+            }
+
+            if (count($checkImagick->queryFormats('PDF')) === 1) {
+                if (\OC_Helper::is_function_enabled('shell_exec')) {
+                    $officeFound = is_string($this->config->getSystemValue('preview_libreoffice_path', null));
+
+                    if (!$officeFound) {
+                        //let's see if there is libreoffice or openoffice on this machine
+                        $whichLibreOffice = shell_exec('command -v libreoffice');
+                        $officeFound = !empty($whichLibreOffice);
+                        if (!$officeFound) {
+                            $whichOpenOffice = shell_exec('command -v openoffice');
+                            $officeFound = !empty($whichOpenOffice);
+                        }
+                    }
+
+                    if ($officeFound) {
+                        $this->registerCoreProvider(Preview\MSOfficeDoc::class, '/application\/msword/');
+                        $this->registerCoreProvider(Preview\MSOffice2003::class, '/application\/vnd.ms-.*/');
+                        $this->registerCoreProvider(Preview\MSOffice2007::class, '/application\/vnd.openxmlformats-officedocument.*/');
+                        $this->registerCoreProvider(Preview\OpenDocument::class, '/application\/vnd.oasis.opendocument.*/');
+                        $this->registerCoreProvider(Preview\StarOffice::class, '/application\/vnd.sun.xml.*/');
+                    }
+                }
+            }
+        }
+
+        // Video requires avconv or ffmpeg
+        if (in_array(Preview\Movie::class, $this->getEnabledDefaultProvider())) {
+            $avconvBinary = \OC_Helper::findBinaryPath('avconv');
+            $ffmpegBinary = $avconvBinary ? null : \OC_Helper::findBinaryPath('ffmpeg');
+
+            if ($avconvBinary || $ffmpegBinary) {
+                // FIXME // a bit hacky but didn't want to use subclasses
+                \OC\Preview\Movie::$avconvBinary = $avconvBinary;
+                \OC\Preview\Movie::$ffmpegBinary = $ffmpegBinary;
+
+                $this->registerCoreProvider(Preview\Movie::class, '/video\/.*/');
+            }
+        }
+    }
 }