Register preview providers on the preview manager instead of OC\Preview

lib/private/preview.php

@@ -510,7 +510,7 @@ class Preview {
 		if (is_null($this->preview)) {
 			$preview = null;
 
-			foreach (self::$providers as $supportedMimeType => $provider) {
+			foreach (self::getProviders() as $supportedMimeType => $provider) {
 				if (!preg_match($supportedMimeType, $this->mimeType)) {
 					continue;
 				}
@@ -757,6 +757,14 @@ class Preview {
 		array_multisort($keys, SORT_DESC, self::$providers);
 	}
 
+	protected static function getProviders() {
+		if (empty(self::$providers)) {
+			self::initProviders();
+		}
+
+		return self::$providers;
+	}
+
 	protected static function registerCoreProviders() {
 		self::registerProvider('OC\Preview\TXT');
 		self::registerProvider('OC\Preview\MarkDown');
@@ -914,60 +922,6 @@ class Preview {
 		$preview->deleteAllPreviews();
 	}
 
-	/**
-	 * Check if a preview can be generated for a file
-	 *
-	 * @param \OC\Files\FileInfo $file
-	 * @return bool
-	 */
-	public static function isAvailable(\OC\Files\FileInfo $file) {
-		if (!\OC_Config::getValue('enable_previews', true)) {
-			return false;
-		}
-
-		$mount = $file->getMountPoint();
-		if ($mount and !$mount->getOption('previews', true)){
-			return false;
-		}
-
-		//check if there are preview backends
-		if (empty(self::$providers)) {
-			self::initProviders();
-		}
-
-		foreach (self::$providers as $supportedMimeType => $provider) {
-			/**
-			 * @var \OC\Preview\Provider $provider
-			 */
-			if (preg_match($supportedMimeType, $file->getMimetype())) {
-				return $provider->isAvailable($file);
-			}
-		}
-		return false;
-	}
-
-	/**
-	 * @param string $mimeType
-	 * @return bool
-	 */
-	public static function isMimeSupported($mimeType) {
-		if (!\OC_Config::getValue('enable_previews', true)) {
-			return false;
-		}
-
-		//check if there are preview backends
-		if (empty(self::$providers)) {
-			self::initProviders();
-		}
-
-		foreach(self::$providers as $supportedMimetype => $provider) {
-			if(preg_match($supportedMimetype, $mimeType)) {
-				return true;
-			}
-		}
-		return false;
-	}
-
 	/**
 	 * @param int $fileId
 	 * @return string

lib/private/preview/provider.php

@@ -16,7 +16,7 @@ abstract class Provider {
 	/**
 	 * Check if a preview can be generated for $path
 	 *
-	 * @param \OC\Files\FileInfo $file
+	 * @param \OCP\Files\FileInfo $file
 	 * @return bool
 	 */
 	public function isAvailable($file) {

lib/private/previewmanager.php

@@ -12,6 +12,26 @@ use OCP\image;
 use OCP\IPreview;
 
 class PreviewManager implements IPreview {
+	/** @var array */
+	protected $providers = [];
+
+	/**
+	 * In order to improve lazy loading a closure can be registered which will be
+	 * called in case preview providers are actually requested
+	 *
+	 * $callable has to return an instance of \OC\Preview\Provider
+	 *
+	 * @param string $mimeTypeRegex Regex with the mime types that are supported by this provider
+	 * @param \Closure $callable
+	 * @return void
+	 */
+	public function registerProvider($mimeTypeRegex, \Closure $callable) {
+		if (!isset($this->providers[$mimeTypeRegex])) {
+			$this->providers[$mimeTypeRegex] = [];
+		}
+		$this->providers[$mimeTypeRegex][] = $callable;
+	}
+
 	/**
 	 * return a preview of a file
 	 *
@@ -33,16 +53,45 @@ class PreviewManager implements IPreview {
 	 * @return boolean
 	 */
 	function isMimeSupported($mimeType = '*') {
-		return \OC\Preview::isMimeSupported($mimeType);
+		if (!\OC::$server->getConfig()->getSystemValue('enable_previews', true)) {
+			return false;
+		}
+
+		$providerMimeTypes = array_keys($this->providers);
+		foreach ($providerMimeTypes as $supportedMimeType) {
+			if (preg_match($supportedMimeType, $mimeType)) {
+				return true;
+			}
+		}
+		return false;
 	}
 
 	/**
 	 * Check if a preview can be generated for a file
 	 *
-	 * @param \OC\Files\FileInfo $file
+	 * @param \OCP\Files\FileInfo $file
 	 * @return bool
 	 */
 	function isAvailable($file) {
-		return \OC\Preview::isAvailable($file);
+		if (!\OC::$server->getConfig()->getSystemValue('enable_previews', true)) {
+			return false;
+		}
+
+		$mount = $file->getMountPoint();
+		if ($mount and !$mount->getOption('previews', true)){
+			return false;
+		}
+
+		foreach ($this->providers as $supportedMimeType => $providers) {
+			if (preg_match($supportedMimeType, $file->getMimetype())) {
+				foreach ($providers as $provider) {
+					/** @var $provider \OC\Preview\Provider */
+					if ($provider->isAvailable($file)) {
+						return true;
+					}
+				}
+			}
+		}
+		return false;
 	}
 }

lib/public/ipreview.php

@@ -36,8 +36,18 @@ namespace OCP;
 /**
  * This class provides functions to render and show thumbnails and previews of files
  */
-interface IPreview
-{
+interface IPreview {
+	/**
+	 * In order to improve lazy loading a closure can be registered which will be
+	 * called in case preview providers are actually requested
+	 *
+	 * $callable has to return an instance of \OC\Preview\Provider
+	 *
+	 * @param string $mimeTypeRegex Regex with the mime types that are supported by this provider
+	 * @param \Closure $callable
+	 * @return void
+	 */
+	public function registerProvider($mimeTypeRegex, \Closure $callable);
 
 	/**
 	 * Return a preview of a file