Merge pull request #15867 from nextcloud/preview-versioning

allow keeping multiple preview "versions" of the same file

4 files changed, 70 insertions, 17 deletions

diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 5d6915cb27e..ca73591d003 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -355,6 +355,7 @@ return array(
     'OCP\\PreConditionNotMetException' => $baseDir . '/lib/public/PreConditionNotMetException.php',
     'OCP\\Preview\\IProvider' => $baseDir . '/lib/public/Preview/IProvider.php',
     'OCP\\Preview\\IProviderV2' => $baseDir . '/lib/public/Preview/IProviderV2.php',
+    'OCP\\Preview\\IVersionedPreviewFile' => $baseDir . '/lib/public/Preview/IVersionedPreviewFile.php',
     'OCP\\Remote\\Api\\IApiCollection' => $baseDir . '/lib/public/Remote/Api/IApiCollection.php',
     'OCP\\Remote\\Api\\IApiFactory' => $baseDir . '/lib/public/Remote/Api/IApiFactory.php',
     'OCP\\Remote\\Api\\ICapabilitiesApi' => $baseDir . '/lib/public/Remote/Api/ICapabilitiesApi.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index a6bd0d927ec..c8c8075ce1a 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -389,6 +389,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OCP\\PreConditionNotMetException' => __DIR__ . '/../../..' . '/lib/public/PreConditionNotMetException.php',
         'OCP\\Preview\\IProvider' => __DIR__ . '/../../..' . '/lib/public/Preview/IProvider.php',
         'OCP\\Preview\\IProviderV2' => __DIR__ . '/../../..' . '/lib/public/Preview/IProviderV2.php',
+        'OCP\\Preview\\IVersionedPreviewFile' => __DIR__ . '/../../..' . '/lib/public/Preview/IVersionedPreviewFile.php',
         'OCP\\Remote\\Api\\IApiCollection' => __DIR__ . '/../../..' . '/lib/public/Remote/Api/IApiCollection.php',
         'OCP\\Remote\\Api\\IApiFactory' => __DIR__ . '/../../..' . '/lib/public/Remote/Api/IApiFactory.php',
         'OCP\\Remote\\Api\\ICapabilitiesApi' => __DIR__ . '/../../..' . '/lib/public/Remote/Api/ICapabilitiesApi.php',
diff --git a/lib/private/Preview/Generator.php b/lib/private/Preview/Generator.php
index f9c020389f9..79c512c84aa 100644
--- a/lib/private/Preview/Generator.php
+++ b/lib/private/Preview/Generator.php
@@ -35,6 +35,8 @@ use OCP\Files\SimpleFS\ISimpleFolder;
 use OCP\IConfig;
 use OCP\IImage;
 use OCP\IPreview;
+use OCP\Preview\IProvider;
+use OCP\Preview\IVersionedPreviewFile;
 use OCP\Preview\IProviderV2;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\EventDispatcher\GenericEvent;
@@ -98,7 +100,7 @@ class Generator {
 
 		$this->eventDispatcher->dispatch(
 			IPreview::EVENT,
-			new GenericEvent($file,[
+			new GenericEvent($file, [
 				'width' => $width,
 				'height' => $height,
 				'crop' => $crop,
@@ -115,14 +117,19 @@ class Generator {
 
 		$previewFolder = $this->getPreviewFolder($file);
 
+		$previewVersion = '';
+		if ($file instanceof IVersionedPreviewFile) {
+			$previewVersion = $file->getPreviewVersion() . '-';
+		}
+
 		// Get the max preview and infer the max preview sizes from that
-		$maxPreview = $this->getMaxPreview($previewFolder, $file, $mimeType);
+		$maxPreview = $this->getMaxPreview($previewFolder, $file, $mimeType, $previewVersion);
 		if ($maxPreview->getSize() === 0) {
 			$maxPreview->delete();
 			throw new NotFoundException('Max preview size 0, invalid!');
 		}
 
-		list($maxWidth, $maxHeight) = $this->getPreviewSize($maxPreview);
+		list($maxWidth, $maxHeight) = $this->getPreviewSize($maxPreview, $previewVersion);
 
 		// If both width and heigth are -1 we just want the max preview
 		if ($width === -1 && $height === -1) {
@@ -141,9 +148,9 @@ class Generator {
 		// Try to get a cached preview. Else generate (and store) one
 		try {
 			try {
-				$preview = $this->getCachedPreview($previewFolder, $width, $height, $crop, $maxPreview->getMimeType());
+				$preview = $this->getCachedPreview($previewFolder, $width, $height, $crop, $maxPreview->getMimeType(), $previewVersion);
 			} catch (NotFoundException $e) {
-				$preview = $this->generatePreview($previewFolder, $maxPreview, $width, $height, $crop, $maxWidth, $maxHeight);
+				$preview = $this->generatePreview($previewFolder, $maxPreview, $width, $height, $crop, $maxWidth, $maxHeight, $previewVersion);
 			}
 		} catch (\InvalidArgumentException $e) {
 			throw new NotFoundException();
@@ -161,14 +168,16 @@ class Generator {
 	 * @param ISimpleFolder $previewFolder
 	 * @param File $file
 	 * @param string $mimeType
+	 * @param string $prefix
 	 * @return ISimpleFile
 	 * @throws NotFoundException
 	 */
-	private function getMaxPreview(ISimpleFolder $previewFolder, File $file, $mimeType) {
+	private function getMaxPreview(ISimpleFolder $previewFolder, File $file, $mimeType, $prefix) {
 		$nodes = $previewFolder->getDirectoryListing();
 
 		foreach ($nodes as $node) {
-			if (strpos($node->getName(), 'max')) {
+			$name = $node->getName();
+			if (($prefix === '' || strpos($name, $prefix) === 0) && strpos($name, 'max')) {
 				return $node;
 			}
 		}
@@ -206,7 +215,7 @@ class Generator {
 					continue;
 				}
 
-				$path = (string)$preview->width() . '-' . (string)$preview->height() . '-max.' . $ext;
+				$path = $prefix . (string)$preview->width() . '-' . (string)$preview->height() . '-max.' . $ext;
 				try {
 					$file = $previewFolder->newFile($path);
 					$file->putContent($preview->data());
@@ -223,10 +232,11 @@ class Generator {
 
 	/**
 	 * @param ISimpleFile $file
+	 * @param string $prefix
 	 * @return int[]
 	 */
-	private function getPreviewSize(ISimpleFile $file) {
-		$size = explode('-', $file->getName());
+	private function getPreviewSize(ISimpleFile $file, string $prefix = '') {
+		$size = explode('-', substr($file->getName(), strlen($prefix)));
 		return [(int)$size[0], (int)$size[1]];
 	}
 
@@ -235,10 +245,11 @@ class Generator {
 	 * @param int $height
 	 * @param bool $crop
 	 * @param string $mimeType
+	 * @param string $prefix
 	 * @return string
 	 */
-	private function generatePath($width, $height, $crop, $mimeType) {
-		$path = (string)$width . '-' . (string)$height;
+	private function generatePath($width, $height, $crop, $mimeType, $prefix) {
+		$path = $prefix . (string)$width . '-' . (string)$height;
 		if ($crop) {
 			$path .= '-crop';
 		}
@@ -249,7 +260,6 @@ class Generator {
 	}
 
 
-
 	/**
 	 * @param int $width
 	 * @param int $height
@@ -346,11 +356,12 @@ class Generator {
 	 * @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, ISimpleFile $maxPreview, $width, $height, $crop, $maxWidth, $maxHeight) {
+	private function generatePreview(ISimpleFolder $previewFolder, ISimpleFile $maxPreview, $width, $height, $crop, $maxWidth, $maxHeight, $prefix) {
 		$preview = $this->helper->getImage($maxPreview);
 
 		if (!$preview->valid()) {
@@ -380,7 +391,7 @@ class Generator {
 		}
 
 
-		$path = $this->generatePath($width, $height, $crop, $preview->dataMimeType());
+		$path = $this->generatePath($width, $height, $crop, $preview->dataMimeType(), $prefix);
 		try {
 			$file = $previewFolder->newFile($path);
 			$file->putContent($preview->data());
@@ -397,12 +408,13 @@ class Generator {
 	 * @param int $height
 	 * @param bool $crop
 	 * @param string $mimeType
+	 * @param string $prefix
 	 * @return ISimpleFile
 	 *
 	 * @throws NotFoundException
 	 */
-	private function getCachedPreview(ISimpleFolder $previewFolder, $width, $height, $crop, $mimeType) {
-		$path = $this->generatePath($width, $height, $crop, $mimeType);
+	private function getCachedPreview(ISimpleFolder $previewFolder, $width, $height, $crop, $mimeType, $prefix) {
+		$path = $this->generatePath($width, $height, $crop, $mimeType, $prefix);
 
 		return $previewFolder->getFile($path);
 	}
diff --git a/lib/public/Preview/IVersionedPreviewFile.php b/lib/public/Preview/IVersionedPreviewFile.php
new file mode 100644
index 00000000000..e4da914da02
--- /dev/null
+++ b/lib/public/Preview/IVersionedPreviewFile.php
@@ -0,0 +1,39 @@
+<?php declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019 Robin Appelman <robin@icewind.nl>
+ *
+ * @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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCP\Preview;
+
+/**
+ * Marks files that should keep multiple preview "versions" for the same file id
+ *
+ * Examples of this are files where the storage backend provides versioning, for those
+ * files, we dont have fileids for the different versions but still need to be able to generate
+ * previews for all versions
+ *
+ * @since 17.0.0
+ */
+interface IVersionedPreviewFile {
+	/**
+	 * @return string
+	 * @since 17.0.0
+	 */
+	public function getPreviewVersion(): string;
+}