Add preview provider for Krita files

Signed-off-by: Julius Härtl <jus@bitgrid.net>

config/config.sample.php

@@ -989,7 +989,6 @@ $CONFIG = [
  *  - OC\Preview\MSOffice2003
  *  - OC\Preview\MSOffice2007
  *  - OC\Preview\MSOfficeDoc
- *  - OC\Preview\OpenDocument
  *  - OC\Preview\PDF
  *  - OC\Preview\Photoshop
  *  - OC\Preview\Postscript
@@ -1018,6 +1017,8 @@ $CONFIG = [
  *  - OC\Preview\PNG
  *  - OC\Preview\TXT
  *  - OC\Preview\XBitmap
+ *  - OC\Preview\OpenDocument
+ *  - OC\Preview\Krita
  */
 'enabledPreviewProviders' => [
 	'OC\Preview\PNG',
@@ -1028,7 +1029,9 @@ $CONFIG = [
 	'OC\Preview\XBitmap',
 	'OC\Preview\MP3',
 	'OC\Preview\TXT',
-	'OC\Preview\MarkDown'
+	'OC\Preview\MarkDown',
+	'OC\Preview\OpenDocument',
+	'OC\Preview\Krita',
 ],
 
 /**

lib/private/Preview/Bundled.php

@@ -23,10 +23,9 @@
 
 namespace OC\Preview;
 
+use OC\Archive\ZIP;
 use OCP\Files\File;
-use OCP\Files\NotPermittedException;
 use OCP\IImage;
-use OCP\Lock\LockedException;
 
 /**
  * Extracts a preview from files that embed them in an ZIP archive
@@ -39,10 +38,9 @@ abstract class Bundled extends ProviderV2 {
 
 		try {
 			$content = $file->fopen('r');
-			$content = stream_get_contents($content);
 			file_put_contents($sourceTmp, $content);
 
-			$zip = new \OC\Archive\ZIP($sourceTmp);
+			$zip = new ZIP($sourceTmp);
 			$zip->extractFile($path, $targetTmp);
 
 			$image = new \OC_Image();

lib/private/Preview/Krita.php

@@ -0,0 +1,52 @@
+<?php
+/**
+ * @copyright Copyright (c) 2020 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @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 OC\Preview;
+
+use OCP\Files\File;
+use OCP\IImage;
+
+class Krita extends Bundled {
+	/**
+	 * {@inheritDoc}
+	 */
+	public function getMimeType(): string {
+		return '/application\/x-krita/';
+	}
+
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getThumbnail(File $file, int $maxX, int $maxY): ?IImage {
+		$image = $this->extractThumbnail($file, 'mergedimage.png');
+		if ($image->valid()) {
+			return $image;
+		}
+		$image = $this->extractThumbnail($file, 'preview.png');
+		if ($image->valid()) {
+			return $image;
+		}
+		return null;
+	}
+}

lib/private/PreviewManager.php

@@ -293,7 +293,8 @@ class PreviewManager implements IPreview {
 			Preview\GIF::class,
 			Preview\BMP::class,
 			Preview\HEIC::class,
-			Preview\XBitmap::class
+			Preview\XBitmap::class,
+			Preview\Krita::class,
 		];
 
 		$this->defaultProviders = $this->config->getSystemValue('enabledPreviewProviders', array_merge([
@@ -340,6 +341,7 @@ class PreviewManager implements IPreview {
 		$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\Krita::class, '/application\/x-krita/');
 		$this->registerCoreProvider(Preview\MP3::class, '/audio\/mpeg/');
 		$this->registerCoreProvider(Preview\OpenDocument::class, '/application\/vnd.oasis.opendocument.*/');