Merge pull request #19495 from nextcloud/preview-generate-batch

optimize batch generation of previews

5 files changed, 248 insertions, 62 deletions

diff --git a/lib/private/Preview/Generator.php b/lib/private/Preview/Generator.php
index f945849c276..650c3a6ba9f 100644
--- a/lib/private/Preview/Generator.php
+++ b/lib/private/Preview/Generator.php
@@ -91,22 +91,37 @@ class Generator {
 	 * @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,
+		];
+		$this->eventDispatcher->dispatch(
+			IPreview::EVENT,
+			new GenericEvent($file, $specification)
+		);
+
+		// 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 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');
 		}
 
-
-		$this->eventDispatcher->dispatch(
-			IPreview::EVENT,
-			new GenericEvent($file, [
-				'width' => $width,
-				'height' => $height,
-				'crop' => $crop,
-				'mode' => $mode
-			])
-		);
-
 		if ($mimeType === null) {
 			$mimeType = $file->getMimeType();
 		}
@@ -123,41 +138,57 @@ class Generator {
 
 		// Get the max preview and infer the max preview sizes from that
 		$maxPreview = $this->getMaxPreview($previewFolder, $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!');
 		}
 
-		list($maxWidth, $maxHeight) = $this->getPreviewSize($maxPreview, $previewVersion);
+		[$maxWidth, $maxHeight] = $this->getPreviewSize($maxPreview, $previewVersion);
 
-		// If both width and heigth are -1 we just want the max preview
-		if ($width === -1 && $height === -1) {
-			$width = $maxWidth;
-			$height = $maxHeight;
-		}
+		$preview = null;
 
-		// Calculate the preview size
-		list($width, $height) = $this->calculateSize($width, $height, $crop, $mode, $maxWidth, $maxHeight);
+		foreach ($specifications as $specification) {
+			$width = $specification['width'] ?? -1;
+			$height = $specification['height'] ?? -1;
+			$crop = $specification['crop'] ?? false;
+			$mode = $specification['mode'] ?? IPreview::MODE_FILL;
 
-		// No need to generate a preview that is just the max preview
-		if ($width === $maxWidth && $height === $maxHeight) {
-			return $maxPreview;
-		}
+			// If both width and heigth are -1 we just want the max preview
+			if ($width === -1 && $height === -1) {
+				$width = $maxWidth;
+				$height = $maxHeight;
+			}
 
-		// Try to get a cached preview. Else generate (and store) one
-		try {
+			// 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 {
-				$preview = $this->getCachedPreview($previewFolder, $width, $height, $crop, $maxPreview->getMimeType(), $previewVersion);
-			} catch (NotFoundException $e) {
-				$preview = $this->generatePreview($previewFolder, $maxPreview, $width, $height, $crop, $maxWidth, $maxHeight, $previewVersion);
+				try {
+					$preview = $this->getCachedPreview($previewFolder, $width, $height, $crop, $maxPreview->getMimeType(), $previewVersion);
+				} catch (NotFoundException $e) {
+					if ($maxPreviewImage === null) {
+						$maxPreviewImage = $this->helper->getImage($maxPreview);
+					}
+
+					$preview = $this->generatePreview($previewFolder, $maxPreviewImage, $width, $height, $crop, $maxWidth, $maxHeight, $previewVersion);
+				}
+			} catch (\InvalidArgumentException $e) {
+				throw new NotFoundException("", 0, $e);
 			}
-		} catch (\InvalidArgumentException $e) {
-			throw new NotFoundException();
-		}
 
-		if ($preview->getSize() === 0) {
-			$preview->delete();
-			throw new NotFoundException('Cached preview size 0, invalid!');
+			if ($preview->getSize() === 0) {
+				$preview->delete();
+				throw new NotFoundException('Cached preview size 0, invalid!');
+			}
 		}
 
 		return $preview;
@@ -360,9 +391,8 @@ class Generator {
 	 * @throws NotFoundException
 	 * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid)
 	 */
-	private function generatePreview(ISimpleFolder $previewFolder, ISimpleFile $maxPreview, $width, $height, $crop, $maxWidth, $maxHeight, $prefix) {
-		$preview = $this->helper->getImage($maxPreview);
-
+	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');
 		}
@@ -380,13 +410,13 @@ class Generator {
 					$scaleH = $maxHeight / $widthR;
 					$scaleW = $width;
 				}
-				$preview->preciseResize((int)round($scaleW), (int)round($scaleH));
+				$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);
-			$preview->crop($cropX, $cropY, $width, $height);
+			$preview = $preview->cropCopy($cropX, $cropY, $width, $height);
 		} else {
-			$preview->resize(max($width, $height));
+			$preview = $maxPreview->resizeCopy(max($width, $height));
 		}
 
 
@@ -448,7 +478,7 @@ class Generator {
 			case 'image/gif':
 				return 'gif';
 			default:
-				throw new \InvalidArgumentException('Not a valid mimetype');
+				throw new \InvalidArgumentException('Not a valid mimetype: "' . $mimeType . '"');
 		}
 	}
 }
diff --git a/lib/private/PreviewManager.php b/lib/private/PreviewManager.php
index adfc04199e3..0734e275926 100644
--- a/lib/private/PreviewManager.php
+++ b/lib/private/PreviewManager.php
@@ -151,6 +151,22 @@ class PreviewManager implements IPreview {
 		return !empty($this->providers);
 	}
 
+	private function getGenerator(): Generator {
+		if ($this->generator === null) {
+			$this->generator = new Generator(
+				$this->config,
+				$this,
+				$this->appData,
+				new GeneratorHelper(
+					$this->rootFolder,
+					$this->config
+				),
+				$this->eventDispatcher
+			);
+		}
+		return $this->generator;
+	}
+
 	/**
 	 * Returns a preview of a file
 	 *
@@ -169,20 +185,22 @@ class PreviewManager implements IPreview {
 	 * @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 $this->getGenerator()->getPreview($file, $width, $height, $crop, $mode, $mimeType);
+	}
 
-		return $this->generator->getPreview($file, $width, $height, $crop, $mode, $mimeType);
+	/**
+	 * Generates previews of a file
+	 *
+	 * @param File $file
+	 * @param 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)
+	 * @since 19.0.0
+	 */
+	public function generatePreviews(File $file, array $specifications, $mimeType = null) {
+		return $this->getGenerator()->generatePreviews($file, $specifications, $mimeType);
 	}
 
 	/**
diff --git a/lib/private/legacy/OC_Image.php b/lib/private/legacy/OC_Image.php
index 829a9b81652..c8a2f6f458c 100644
--- a/lib/private/legacy/OC_Image.php
+++ b/lib/private/legacy/OC_Image.php
@@ -39,6 +39,8 @@
  *
  */
 
+use OCP\IImage;
+
 /**
  * Class for basic image manipulation
  */
@@ -845,6 +847,17 @@ class OC_Image implements \OCP\IImage {
 	 * @return bool
 	 */
 	public function resize($maxSize) {
+		$result = $this->resizeNew($maxSize);
+		imagedestroy($this->resource);
+		$this->resource = $result;
+		return is_resource($result);
+	}
+
+	/**
+	 * @param $maxSize
+	 * @return resource | bool
+	 */
+	private function resizeNew($maxSize) {
 		if (!$this->valid()) {
 			$this->logger->error(__METHOD__ . '(): No image loaded', ['app' => 'core']);
 			return false;
@@ -861,8 +874,7 @@ class OC_Image implements \OCP\IImage {
 			$newHeight = $maxSize;
 		}
 
-		$this->preciseResize((int)round($newWidth), (int)round($newHeight));
-		return true;
+		return $this->preciseResizeNew((int)round($newWidth), (int)round($newHeight));
 	}
 
 	/**
@@ -871,6 +883,19 @@ class OC_Image implements \OCP\IImage {
 	 * @return bool
 	 */
 	public function preciseResize(int $width, int $height): bool {
+		$result = $this->preciseResizeNew($width, $height);
+		imagedestroy($this->resource);
+		$this->resource = $result;
+		return is_resource($result);
+	}
+
+
+	/**
+	 * @param int $width
+	 * @param int $height
+	 * @return resource | bool
+	 */
+	public function preciseResizeNew(int $width, int $height) {
 		if (!$this->valid()) {
 			$this->logger->error(__METHOD__ . '(): No image loaded', ['app' => 'core']);
 			return false;
@@ -896,9 +921,7 @@ class OC_Image implements \OCP\IImage {
 			imagedestroy($process);
 			return false;
 		}
-		imagedestroy($this->resource);
-		$this->resource = $process;
-		return true;
+		return $process;
 	}
 
 	/**
@@ -969,6 +992,22 @@ class OC_Image implements \OCP\IImage {
 	 * @return bool for success or failure
 	 */
 	public function crop(int $x, int $y, int $w, int $h): bool {
+		$result = $this->cropNew($x, $y, $w, $h);
+		imagedestroy($this->resource);
+		$this->resource = $result;
+		return is_resource($result);
+	}
+
+	/**
+	 * Crops the image from point $x$y with dimension $wx$h.
+	 *
+	 * @param int $x Horizontal position
+	 * @param int $y Vertical position
+	 * @param int $w Width
+	 * @param int $h Height
+	 * @return resource | bool
+	 */
+	public function cropNew(int $x, int $y, int $w, int $h) {
 		if (!$this->valid()) {
 			$this->logger->error(__METHOD__ . '(): No image loaded', ['app' => 'core']);
 			return false;
@@ -993,9 +1032,7 @@ class OC_Image implements \OCP\IImage {
 			imagedestroy($process);
 			return false;
 		}
-		imagedestroy($this->resource);
-		$this->resource = $process;
-		return true;
+		return $process;
 	}
 
 	/**
@@ -1045,6 +1082,55 @@ class OC_Image implements \OCP\IImage {
 		return false;
 	}
 
+	public function copy(): IImage {
+		$image = new OC_Image(null, $this->logger, $this->config);
+		$image->resource = imagecreatetruecolor($this->width(), $this->height());
+		imagecopy(
+			$image->resource(),
+			$this->resource(),
+			0,
+			0,
+			0,
+			0,
+			$this->width(),
+			$this->height()
+		);
+
+		return $image;
+	}
+
+	public function cropCopy(int $x, int $y, int $w, int $h): IImage {
+		$image = new OC_Image(null, $this->logger, $this->config);
+		$image->resource = $this->cropNew($x, $y, $w, $h);
+
+		return $image;
+	}
+
+	public function preciseResizeCopy(int $width, int $height): IImage {
+		$image = new OC_Image(null, $this->logger, $this->config);
+		$image->resource = $this->preciseResizeNew($width, $height);
+
+		return $image;
+	}
+
+	public function resizeCopy(int $maxSize): IImage {
+		$image = new OC_Image(null, $this->logger, $this->config);
+		$image->resource = $this->resizeNew($maxSize);
+
+		return $image;
+	}
+
+
+	/**
+	 * Resizes the image preserving ratio, returning a new copy
+	 *
+	 * @param integer $maxSize The maximum size of either the width or height.
+	 * @return bool
+	 */
+	public function copyResize($maxSize): IImage {
+
+	}
+
 	/**
 	 * Destroys the current image and resets the object
 	 */
diff --git a/lib/public/IImage.php b/lib/public/IImage.php
index 67db6b097ef..6e6c28609d8 100644
--- a/lib/public/IImage.php
+++ b/lib/public/IImage.php
@@ -190,4 +190,43 @@ interface IImage {
 	 * @since 8.1.0
 	 */
 	public function scaleDownToFit($maxWidth, $maxHeight);
+
+	/**
+	 * create a copy of this image
+	 *
+	 * @return IImage
+	 * @since 19.0.0
+	 */
+	public function copy(): IImage;
+
+	/**
+	 * create a new cropped copy of this image
+	 *
+	 * @param int $x Horizontal position
+	 * @param int $y Vertical position
+	 * @param int $w Width
+	 * @param int $h Height
+	 * @return IImage
+	 * @since 19.0.0
+	 */
+	public function cropCopy(int $x, int $y, int $w, int $h): IImage;
+
+	/**
+	 * create a new resized copy of this image
+	 *
+	 * @param int $width
+	 * @param int $height
+	 * @return IImage
+	 * @since 19.0.0
+	 */
+	public function preciseResizeCopy(int $width, int $height): IImage;
+
+	/**
+	 * create a new resized copy of this image
+	 *
+	 * @param integer $maxSize The maximum size of either the width or height.
+	 * @return IImage
+	 * @since 19.0.0
+	 */
+	public function resizeCopy(int $maxSize): IImage;
 }
diff --git a/lib/public/IPreview.php b/lib/public/IPreview.php
index b377d285acb..164cbbac2bf 100644
--- a/lib/public/IPreview.php
+++ b/lib/public/IPreview.php
@@ -115,4 +115,17 @@ interface IPreview {
 	 * @since 8.0.0
 	 */
 	public function isAvailable(\OCP\Files\FileInfo $file);
+
+	/**
+	 * Generates previews of a file
+	 *
+	 * @param File $file
+	 * @param 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)
+	 * @since 19.0.0
+	 */
+	public function generatePreviews(File $file, array $specifications, $mimeType = null);
 }