Fix max preview, some resizing and caching issues and force preview providers to resize their previews properly

* introduces a method in OC_Image which doesn't stretch images when trying to make them fit in a box
* adds the method to all key providers so that they can do their job, as expected by the Preview class
* improves the caching mechanism of Preview in order to reduce I/O and to avoid filling the available disk space
* fixes some long standing issues
* **contains mostly tests**

6 files changed, 44 insertions, 21 deletions

diff --git a/lib/private/preview/image.php b/lib/private/preview/image.php
index 2c69d29f4cb..dbaf5deb08d 100644
--- a/lib/private/preview/image.php
+++ b/lib/private/preview/image.php
@@ -33,7 +33,7 @@ abstract class Image extends Provider {
 	public function getThumbnail($path, $maxX, $maxY, $scalingup, $fileview) {
 		//get fileinfo
 		$fileInfo = $fileview->getFileInfo($path);
-		if(!$fileInfo) {
+		if (!$fileInfo) {
 			return false;
 		}
 
@@ -46,15 +46,19 @@ abstract class Image extends Provider {
 
 		$image = new \OC_Image();
 
-		if($fileInfo['encrypted'] === true) {
+		if ($fileInfo['encrypted'] === true) {
 			$fileName = $fileview->toTmpFile($path);
 		} else {
 			$fileName = $fileview->getLocalFile($path);
 		}
 		$image->loadFromFile($fileName);
 		$image->fixOrientation();
+		if ($image->valid()) {
+			$image->scaleDownToFit($maxX, $maxY);
 
-		return $image->valid() ? $image : false;
+			return $image;
+		}
+		return false;
 	}
 
 }
diff --git a/lib/private/preview/movie.php b/lib/private/preview/movie.php
index 1773f916a88..43e49bfb747 100644
--- a/lib/private/preview/movie.php
+++ b/lib/private/preview/movie.php
@@ -91,7 +91,6 @@ class Movie extends Provider {
 			$cmd = self::$ffmpegBinary . ' -y -ss ' . escapeshellarg($second) .
 				' -i ' . escapeshellarg($absPath) .
 				' -f mjpeg -vframes 1' .
-				' -s ' . escapeshellarg($maxX) . 'x' . escapeshellarg($maxY) .
 				' ' . escapeshellarg($tmpPath) .
 				' > /dev/null 2>&1';
 		}
@@ -102,7 +101,11 @@ class Movie extends Provider {
 			$image = new \OC_Image();
 			$image->loadFromFile($tmpPath);
 			unlink($tmpPath);
-			return $image->valid() ? $image : false;
+			if ($image->valid()) {
+				$image->scaleDownToFit($maxX, $maxY);
+
+				return $image;
+			}
 		}
 		unlink($tmpPath);
 		return false;
diff --git a/lib/private/preview/mp3.php b/lib/private/preview/mp3.php
index ebeb5b989ce..49667d0dd05 100644
--- a/lib/private/preview/mp3.php
+++ b/lib/private/preview/mp3.php
@@ -47,7 +47,12 @@ class MP3 extends Provider {
 			unlink($tmpPath);
 			$image = new \OC_Image();
 			$image->loadFromData($picture);
-			return $image->valid() ? $image : $this->getNoCoverThumbnail();
+
+			if ($image->valid()) {
+				$image->scaleDownToFit($maxX, $maxY);
+
+				return $image;
+			}
 		}
 
 		return $this->getNoCoverThumbnail();
diff --git a/lib/private/preview/office.php b/lib/private/preview/office.php
index 54c0c26c079..0a61a32df40 100644
--- a/lib/private/preview/office.php
+++ b/lib/private/preview/office.php
@@ -29,7 +29,7 @@ abstract class Office extends Provider {
 	 */
 	public function getThumbnail($path, $maxX, $maxY, $scalingup, $fileview) {
 		$this->initCmd();
-		if(is_null($this->cmd)) {
+		if (is_null($this->cmd)) {
 			return false;
 		}
 
@@ -37,7 +37,7 @@ abstract class Office extends Provider {
 
 		$tmpDir = get_temp_dir();
 
-		$defaultParameters = ' -env:UserInstallation=file://' . escapeshellarg($tmpDir . '/owncloud-' . \OC_Util::getInstanceId().'/') . ' --headless --nologo --nofirststartwizard --invisible --norestore --convert-to pdf --outdir ';
+		$defaultParameters = ' -env:UserInstallation=file://' . escapeshellarg($tmpDir . '/owncloud-' . \OC_Util::getInstanceId() . '/') . ' --headless --nologo --nofirststartwizard --invisible --norestore --convert-to pdf --outdir ';
 		$clParameters = \OCP\Config::getSystemValue('preview_office_cl_parameters', $defaultParameters);
 
 		$exec = $this->cmd . $clParameters . escapeshellarg($tmpDir) . ' ' . escapeshellarg($absPath);
@@ -46,8 +46,8 @@ abstract class Office extends Provider {
 
 		//create imagick object from pdf
 		$pdfPreview = null;
-		try{
-			list( $dirname, , , $filename ) = array_values( pathinfo($absPath) );
+		try {
+			list($dirname, , , $filename) = array_values(pathinfo($absPath));
 			$pdfPreview = $dirname . '/' . $filename . '.pdf';
 
 			$pdf = new \imagick($pdfPreview . '[0]');
@@ -65,27 +65,33 @@ abstract class Office extends Provider {
 		unlink($absPath);
 		unlink($pdfPreview);
 
-		return $image->valid() ? $image : false;
+		if ($image->valid()) {
+			$image->scaleDownToFit($maxX, $maxY);
+
+			return $image;
+		}
+		return false;
+
 	}
 
 	private function initCmd() {
 		$cmd = '';
 
-		if(is_string(\OC_Config::getValue('preview_libreoffice_path', null))) {
+		if (is_string(\OC_Config::getValue('preview_libreoffice_path', null))) {
 			$cmd = \OC_Config::getValue('preview_libreoffice_path', null);
 		}
 
 		$whichLibreOffice = shell_exec('command -v libreoffice');
-		if($cmd === '' && !empty($whichLibreOffice)) {
+		if ($cmd === '' && !empty($whichLibreOffice)) {
 			$cmd = 'libreoffice';
 		}
 
 		$whichOpenOffice = shell_exec('command -v openoffice');
-		if($cmd === '' && !empty($whichOpenOffice)) {
+		if ($cmd === '' && !empty($whichOpenOffice)) {
 			$cmd = 'openoffice';
 		}
 
-		if($cmd === '') {
+		if ($cmd === '') {
 			$cmd = null;
 		}
 
diff --git a/lib/private/preview/provider.php b/lib/private/preview/provider.php
index ade91b8e232..ed1f3a1c5c9 100644
--- a/lib/private/preview/provider.php
+++ b/lib/private/preview/provider.php
@@ -1,7 +1,6 @@
 <?php
 /**
  * @author Georg Ehrke <georg@owncloud.com>
- * @author Georg Ehrke <georg@ownCloud.com>
  * @author Joas Schilling <nickvergessen@owncloud.com>
  * @author Jörn Friedrich Dreyer <jfd@butonic.de>
  * @author Robin Appelman <icewind@owncloud.com>
@@ -54,7 +53,8 @@ abstract class Provider implements IProvider {
 	}
 
 	/**
-	 * get thumbnail for file at path $path
+	 * Generates thumbnail which fits in $maxX and $maxY and keeps the aspect ratio, for file at path $path
+	 *
 	 * @param string $path Path of file
 	 * @param int $maxX The maximum X size of the thumbnail. It can be smaller depending on the shape of the image
 	 * @param int $maxY The maximum Y size of the thumbnail. It can be smaller depending on the shape of the image
diff --git a/lib/private/preview/svg.php b/lib/private/preview/svg.php
index 7c74fb6fde2..92d21c07385 100644
--- a/lib/private/preview/svg.php
+++ b/lib/private/preview/svg.php
@@ -35,17 +35,17 @@ class SVG extends Provider {
 	 * {@inheritDoc}
 	 */
 	public function getThumbnail($path, $maxX, $maxY, $scalingup, $fileview) {
-		try{
+		try {
 			$svg = new \Imagick();
 			$svg->setBackgroundColor(new \ImagickPixel('transparent'));
 
 			$content = stream_get_contents($fileview->fopen($path, 'r'));
-			if(substr($content, 0, 5) !== '<?xml') {
+			if (substr($content, 0, 5) !== '<?xml') {
 				$content = '<?xml version="1.0" encoding="UTF-8" standalone="no"?>' . $content;
 			}
 
 			// Do not parse SVG files with references
-			if(stripos($content, 'xlink:href') !== false) {
+			if (stripos($content, 'xlink:href') !== false) {
 				return false;
 			}
 
@@ -60,6 +60,11 @@ class SVG extends Provider {
 		$image = new \OC_Image();
 		$image->loadFromData($svg);
 		//check if image object is valid
-		return $image->valid() ? $image : false;
+		if ($image->valid()) {
+			$image->scaleDownToFit($maxX, $maxY);
+
+			return $image;
+		}
+		return false;
 	}
 }