* * @author Christoph Wurst * @author Elijah Martin-Merrill * @author J0WI * @author John Molakvoæ * @author Morris Jobke * @author Robin Appelman * @author Roeland Jago Douma * @author Scott Dutton * * @license GNU AGPL version 3 or any later version * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see . * */ namespace OC\Preview; use OCP\EventDispatcher\IEventDispatcher; use OCP\Files\File; use OCP\Files\IAppData; use OCP\Files\InvalidPathException; use OCP\Files\NotFoundException; use OCP\Files\NotPermittedException; use OCP\Files\SimpleFS\ISimpleFile; use OCP\Files\SimpleFS\ISimpleFolder; use OCP\IConfig; use OCP\IImage; use OCP\IPreview; use OCP\IStreamImage; use OCP\Preview\BeforePreviewFetchedEvent; use OCP\Preview\IProviderV2; use OCP\Preview\IVersionedPreviewFile; class Generator { public const SEMAPHORE_ID_ALL = 0x0a11; public const SEMAPHORE_ID_NEW = 0x07ea; /** @var IPreview */ private $previewManager; /** @var IConfig */ private $config; /** @var IAppData */ private $appData; /** @var GeneratorHelper */ private $helper; /** @var IEventDispatcher */ private $eventDispatcher; public function __construct( IConfig $config, IPreview $previewManager, IAppData $appData, GeneratorHelper $helper, IEventDispatcher $eventDispatcher ) { $this->config = $config; $this->previewManager = $previewManager; $this->appData = $appData; $this->helper = $helper; $this->eventDispatcher = $eventDispatcher; } /** * 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|null $mimeType * @return ISimpleFile * @throws NotFoundException * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid) */ public function getPreview(File $file, $width = -1, $height = -1, $crop = false, $mode = IPreview::MODE_FILL, $mimeType = null) { $specification = [ 'width' => $width, 'height' => $height, 'crop' => $crop, 'mode' => $mode, ]; $this->eventDispatcher->dispatchTyped(new BeforePreviewFetchedEvent( $file, $width, $height, $crop, $mode, )); // since we only ask for one preview, and the generate method return the last one it created, it returns the one we want return $this->generatePreviews($file, [$specification], $mimeType); } /** * Generates previews of a file * * @param File $file * @param non-empty-array $specifications * @param string $mimeType * @return ISimpleFile the last preview that was generated * @throws NotFoundException * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid) */ public function generatePreviews(File $file, array $specifications, $mimeType = null) { //Make sure that we can read the file if (!$file->isReadable()) { throw new NotFoundException('Cannot read file'); } if ($mimeType === null) { $mimeType = $file->getMimeType(); } $previewFolder = $this->getPreviewFolder($file); // List every existing preview first instead of trying to find them one by one $previewFiles = $previewFolder->getDirectoryListing(); $previewVersion = ''; if ($file instanceof IVersionedPreviewFile) { $previewVersion = $file->getPreviewVersion() . '-'; } // Get the max preview and infer the max preview sizes from that $maxPreview = $this->getMaxPreview($previewFolder, $previewFiles, $file, $mimeType, $previewVersion); $maxPreviewImage = null; // only load the image when we need it if ($maxPreview->getSize() === 0) { $maxPreview->delete(); throw new NotFoundException('Max preview size 0, invalid!'); } [$maxWidth, $maxHeight] = $this->getPreviewSize($maxPreview, $previewVersion); if ($maxWidth <= 0 || $maxHeight <= 0) { throw new NotFoundException('The maximum preview sizes are zero or less pixels'); } $preview = null; foreach ($specifications as $specification) { $width = $specification['width'] ?? -1; $height = $specification['height'] ?? -1; $crop = $specification['crop'] ?? false; $mode = $specification['mode'] ?? IPreview::MODE_FILL; // If both width and height are -1 we just want the max preview if ($width === -1 && $height === -1) { $width = $maxWidth; $height = $maxHeight; } // Calculate the preview size [$width, $height] = $this->calculateSize($width, $height, $crop, $mode, $maxWidth, $maxHeight); // No need to generate a preview that is just the max preview if ($width === $maxWidth && $height === $maxHeight) { // ensure correct return value if this was the last one $preview = $maxPreview; continue; } // Try to get a cached preview. Else generate (and store) one try { try { $preview = $this->getCachedPreview($previewFiles, $width, $height, $crop, $maxPreview->getMimeType(), $previewVersion); } catch (NotFoundException $e) { if (!$this->previewManager->isMimeSupported($mimeType)) { throw new NotFoundException(); } if ($maxPreviewImage === null) { $maxPreviewImage = $this->helper->getImage($maxPreview); } $preview = $this->generatePreview($previewFolder, $maxPreviewImage, $width, $height, $crop, $maxWidth, $maxHeight, $previewVersion); // New file, augment our array $previewFiles[] = $preview; } } catch (\InvalidArgumentException $e) { throw new NotFoundException("", 0, $e); } if ($preview->getSize() === 0) { $preview->delete(); throw new NotFoundException('Cached preview size 0, invalid!'); } } assert($preview !== null); // Free memory being used by the embedded image resource. Without this the image is kept in memory indefinitely. // Garbage Collection does NOT free this memory. We have to do it ourselves. if ($maxPreviewImage instanceof \OCP\Image) { $maxPreviewImage->destroy(); } return $preview; } /** * Acquire a semaphore of the specified id and concurrency, blocking if necessary. * Return an identifier of the semaphore on success, which can be used to release it via * {@see Generator::unguardWithSemaphore()}. * * @param int $semId * @param int $concurrency * @return false|\SysvSemaphore the semaphore on success or false on failure */ public static function guardWithSemaphore(int $semId, int $concurrency) { if (!extension_loaded('sysvsem')) { return false; } $sem = sem_get($semId, $concurrency); if ($sem === false) { return false; } if (!sem_acquire($sem)) { return false; } return $sem; } /** * Releases the semaphore acquired from {@see Generator::guardWithSemaphore()}. * * @param false|\SysvSemaphore $semId the semaphore identifier returned by guardWithSemaphore * @return bool */ public static function unguardWithSemaphore(false|\SysvSemaphore $semId): bool { if ($semId === false || !($semId instanceof \SysvSemaphore)) { return false; } return sem_release($semId); } /** * Get the number of concurrent threads supported by the host. * * @return int number of concurrent threads, or 0 if it cannot be determined */ public static function getHardwareConcurrency(): int { static $width; if (!isset($width)) { if (function_exists('ini_get')) { $openBasedir = ini_get('open_basedir'); if (empty($openBasedir) || strpos($openBasedir, '/proc/cpuinfo') !== false) { $width = is_readable('/proc/cpuinfo') ? substr_count(file_get_contents('/proc/cpuinfo'), 'processor') : 0; } else { $width = 0; } } else { $width = 0; } } return $width; } /** * Get number of concurrent preview generations from system config * * Two config entries, `preview_concurrency_new` and `preview_concurrency_all`, * are available. If not set, the default values are determined with the hardware concurrency * of the host. In case the hardware concurrency cannot be determined, or the user sets an * invalid value, fallback values are: * For new images whose previews do not exist and need to be generated, 4; * For all preview generation requests, 8. * Value of `preview_concurrency_all` should be greater than or equal to that of * `preview_concurrency_new`, otherwise, the latter is returned. * * @param string $type either `preview_concurrency_new` or `preview_concurrency_all` * @return int number of concurrent preview generations, or -1 if $type is invalid */ public function getNumConcurrentPreviews(string $type): int { static $cached = []; if (array_key_exists($type, $cached)) { return $cached[$type]; } $hardwareConcurrency = self::getHardwareConcurrency(); switch ($type) { case "preview_concurrency_all": $fallback = $hardwareConcurrency > 0 ? $hardwareConcurrency * 2 : 8; $concurrency_all = $this->config->getSystemValueInt($type, $fallback); $concurrency_new = $this->getNumConcurrentPreviews("preview_concurrency_new"); $cached[$type] = max($concurrency_all, $concurrency_new); break; case "preview_concurrency_new": $fallback = $hardwareConcurrency > 0 ? $hardwareConcurrency : 4; $cached[$type] = $this->config->getSystemValueInt($type, $fallback); break; default: return -1; } return $cached[$type]; } /** * @param ISimpleFolder $previewFolder * @param ISimpleFile[] $previewFiles * @param File $file * @param string $mimeType * @param string $prefix * @return ISimpleFile * @throws NotFoundException */ private function getMaxPreview(ISimpleFolder $previewFolder, array $previewFiles, File $file, $mimeType, $prefix) { // We don't know the max preview size, so we can't use getCachedPreview. // It might have been generated with a higher resolution than the current value. foreach ($previewFiles as $node) { $name = $node->getName(); if (($prefix === '' || str_starts_with($name, $prefix)) && strpos($name, 'max')) { return $node; } } $maxWidth = $this->config->getSystemValueInt('preview_max_x', 4096); $maxHeight = $this->config->getSystemValueInt('preview_max_y', 4096); return $this->generateProviderPreview($previewFolder, $file, $maxWidth, $maxHeight, false, true, $mimeType, $prefix); } private function generateProviderPreview(ISimpleFolder $previewFolder, File $file, int $width, int $height, bool $crop, bool $max, string $mimeType, string $prefix) { $previewProviders = $this->previewManager->getProviders(); foreach ($previewProviders as $supportedMimeType => $providers) { // Filter out providers that does not support this mime if (!preg_match($supportedMimeType, $mimeType)) { continue; } foreach ($providers as $providerClosure) { $provider = $this->helper->getProvider($providerClosure); if (!($provider instanceof IProviderV2)) { continue; } if (!$provider->isAvailable($file)) { continue; } $previewConcurrency = $this->getNumConcurrentPreviews('preview_concurrency_new'); $sem = self::guardWithSemaphore(self::SEMAPHORE_ID_NEW, $previewConcurrency); try { $preview = $this->helper->getThumbnail($provider, $file, $width, $height); } finally { self::unguardWithSemaphore($sem); } if (!($preview instanceof IImage)) { continue; } $path = $this->generatePath($preview->width(), $preview->height(), $crop, $max, $preview->dataMimeType(), $prefix); try { $file = $previewFolder->newFile($path); if ($preview instanceof IStreamImage) { $file->putContent($preview->resource()); } else { $file->putContent($preview->data()); } } catch (NotPermittedException $e) { throw new NotFoundException(); } return $file; } } throw new NotFoundException('No provider successfully handled the preview generation'); } /** * @param ISimpleFile $file * @param string $prefix * @return int[] */ private function getPreviewSize(ISimpleFile $file, string $prefix = '') { $size = explode('-', substr($file->getName(), strlen($prefix))); return [(int)$size[0], (int)$size[1]]; } /** * @param int $width * @param int $height * @param bool $crop * @param bool $max * @param string $mimeType * @param string $prefix * @return string */ private function generatePath($width, $height, $crop, $max, $mimeType, $prefix) { $path = $prefix . (string)$width . '-' . (string)$height; if ($crop) { $path .= '-crop'; } if ($max) { $path .= '-max'; } $ext = $this->getExtension($mimeType); $path .= '.' . $ext; return $path; } /** * @param int $width * @param int $height * @param bool $crop * @param string $mode * @param int $maxWidth * @param int $maxHeight * @return int[] */ private function calculateSize($width, $height, $crop, $mode, $maxWidth, $maxHeight) { /* * If we are not cropping we have to make sure the requested image * respects the aspect ratio of the original. */ if (!$crop) { $ratio = $maxHeight / $maxWidth; if ($width === -1) { $width = $height / $ratio; } if ($height === -1) { $height = $width * $ratio; } $ratioH = $height / $maxHeight; $ratioW = $width / $maxWidth; /* * Fill means that the $height and $width are the max * Cover means min. */ if ($mode === IPreview::MODE_FILL) { if ($ratioH > $ratioW) { $height = $width * $ratio; } else { $width = $height / $ratio; } } elseif ($mode === IPreview::MODE_COVER) { if ($ratioH > $ratioW) { $width = $height / $ratio; } else { $height = $width * $ratio; } } } if ($height !== $maxHeight && $width !== $maxWidth) { /* * Scale to the nearest power of four */ $pow4height = 4 ** ceil(log($height) / log(4)); $pow4width = 4 ** ceil(log($width) / log(4)); // Minimum size is 64 $pow4height = max($pow4height, 64); $pow4width = max($pow4width, 64); $ratioH = $height / $pow4height; $ratioW = $width / $pow4width; if ($ratioH < $ratioW) { $width = $pow4width; $height /= $ratioW; } else { $height = $pow4height; $width /= $ratioH; } } /* * Make sure the requested height and width fall within the max * of the preview. */ if ($height > $maxHeight) { $ratio = $height / $maxHeight; $height = $maxHeight; $width /= $ratio; } if ($width > $maxWidth) { $ratio = $width / $maxWidth; $width = $maxWidth; $height /= $ratio; } return [(int)round($width), (int)round($height)]; } /** * @param ISimpleFolder $previewFolder * @param ISimpleFile $maxPreview * @param int $width * @param int $height * @param bool $crop * @param int $maxWidth * @param int $maxHeight * @param string $prefix * @return ISimpleFile * @throws NotFoundException * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid) */ private function generatePreview(ISimpleFolder $previewFolder, IImage $maxPreview, $width, $height, $crop, $maxWidth, $maxHeight, $prefix) { $preview = $maxPreview; if (!$preview->valid()) { throw new \InvalidArgumentException('Failed to generate preview, failed to load image'); } $previewConcurrency = $this->getNumConcurrentPreviews('preview_concurrency_new'); $sem = self::guardWithSemaphore(self::SEMAPHORE_ID_NEW, $previewConcurrency); try { if ($crop) { if ($height !== $preview->height() && $width !== $preview->width()) { //Resize $widthR = $preview->width() / $width; $heightR = $preview->height() / $height; if ($widthR > $heightR) { $scaleH = $height; $scaleW = $maxWidth / $heightR; } else { $scaleH = $maxHeight / $widthR; $scaleW = $width; } $preview = $preview->preciseResizeCopy((int)round($scaleW), (int)round($scaleH)); } $cropX = (int)floor(abs($width - $preview->width()) * 0.5); $cropY = (int)floor(abs($height - $preview->height()) * 0.5); $preview = $preview->cropCopy($cropX, $cropY, $width, $height); } else { $preview = $maxPreview->resizeCopy(max($width, $height)); } } finally { self::unguardWithSemaphore($sem); } $path = $this->generatePath($width, $height, $crop, false, $preview->dataMimeType(), $prefix); try { $file = $previewFolder->newFile($path); $file->putContent($preview->data()); } catch (NotPermittedException $e) { throw new NotFoundException(); } return $file; } /** * @param ISimpleFile[] $files Array of FileInfo, as the result of getDirectoryListing() * @param int $width * @param int $height * @param bool $crop * @param string $mimeType * @param string $prefix * @return ISimpleFile * * @throws NotFoundException */ private function getCachedPreview($files, $width, $height, $crop, $mimeType, $prefix) { $path = $this->generatePath($width, $height, $crop, false, $mimeType, $prefix); foreach ($files as $file) { if ($file->getName() === $path) { return $file; } } throw new NotFoundException(); } /** * Get the specific preview folder for this file * * @param File $file * @return ISimpleFolder * * @throws InvalidPathException * @throws NotFoundException * @throws NotPermittedException */ private function getPreviewFolder(File $file) { // Obtain file id outside of try catch block to prevent the creation of an existing folder $fileId = (string)$file->getId(); try { $folder = $this->appData->getFolder($fileId); } catch (NotFoundException $e) { $folder = $this->appData->newFolder($fileId); } return $folder; } /** * @param string $mimeType * @return null|string * @throws \InvalidArgumentException */ private function getExtension($mimeType) { switch ($mimeType) { case 'image/png': return 'png'; case 'image/jpeg': return 'jpg'; case 'image/webp': return 'webp'; case 'image/gif': return 'gif'; default: throw new \InvalidArgumentException('Not a valid mimetype: "' . $mimeType . '"'); } } }