allow generating multiple preview sizes for a single file at once

this saves having to do some of the overhead multiple times

Signed-off-by: Robin Appelman <robin@icewind.nl>

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();
 		}
@@ -128,7 +143,15 @@ class Generator {
 			throw new NotFoundException('Max preview size 0, invalid!');
 		}
 
-		list($maxWidth, $maxHeight) = $this->getPreviewSize($maxPreview, $previewVersion);
+		[$maxWidth, $maxHeight] = $this->getPreviewSize($maxPreview, $previewVersion);
+
+		$preview = null;
+
+		foreach ($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 heigth are -1 we just want the max preview
 			if ($width === -1 && $height === -1) {
@@ -137,11 +160,13 @@ class Generator {
 			}
 
 			// Calculate the preview size
-		list($width, $height) = $this->calculateSize($width, $height, $crop, $mode, $maxWidth, $maxHeight);
+			[$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) {
-			return $maxPreview;
+				// ensure correct return value if this was the last one
+				$preview = $maxPreview;
+				continue;
 			}
 
 			// Try to get a cached preview. Else generate (and store) one
@@ -159,6 +184,7 @@ class Generator {
 				$preview->delete();
 				throw new NotFoundException('Cached preview size 0, invalid!');
 			}
+		}
 
 		return $preview;
 	}

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) {
+		return $this->getGenerator()->getPreview($file, $width, $height, $crop, $mode, $mimeType);
-			$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);
+	/**
+	 * 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);
 	}
 
 	/**

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);
 }