use JSqueeze instead of JSMin (owncloud#13052)

The JSMin minifier is non-free. JSqueeze is free, it's also a
currently-maintained project following good development
practices, and the best-performing minifier we tested. This
requires a corresponding 3rdparty commit to drop mrclay/minify
and add JSqueeze, and also uses a backport of the latest
upstream version of the Assetic JSqueeze filter as the current
version in 1.2 does not work with JSqueeze 2.x. The backported
filter file can be dropped when our bundled copy of Assetic is
updated to a version containing the newer JSqueezeFilter.

lib/private/assetic/jsqueeze2filter.php

@@ -0,0 +1,97 @@
+<?php
+
+/**
+ * Copyright (c) 2010-2014 OpenSky Project Inc
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is furnished
+ * to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * This file is just a copy of Assetic's JSqueezeFilter following
+ * https://github.com/kriswallsmith/assetic/pull/698, with the class
+ * renamed to JSqueeze2Filter, namespace changed, and use statements
+ * adjusted. It can be dropped as soon as OC's bundled Assetic is updated
+ * to a version containing the JSqueezeFilter that works with JSqueeze 2.x.
+ */
+
+namespace OC\Assetic;
+
+use Assetic\Filter\FilterInterface;
+use Assetic\Asset\AssetInterface;
+
+/**
+ * JSqueeze filter.
+ *
+ * @link https://github.com/nicolas-grekas/JSqueeze
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class JSqueeze2Filter implements FilterInterface
+{
+    private $singleLine = true;
+    private $keepImportantComments = true;
+    private $className;
+    private $specialVarRx = false;
+    private $defaultRx;
+
+    public function __construct()
+    {
+        // JSqueeze is namespaced since 2.x, this works with both 1.x and 2.x
+        if (class_exists('\\Patchwork\\JSqueeze')) {
+            $this->className = '\\Patchwork\\JSqueeze';
+            $this->defaultRx = \Patchwork\JSqueeze::SPECIAL_VAR_PACKER;
+        } else {
+            $this->className = '\\JSqueeze';
+            $this->defaultRx = \JSqueeze::SPECIAL_VAR_RX;
+        }
+    }
+
+    public function setSingleLine($bool)
+    {
+        $this->singleLine = (bool) $bool;
+    }
+
+    // call setSpecialVarRx(true) to enable global var/method/property
+    // renaming with the default regex (for 1.x or 2.x)
+    public function setSpecialVarRx($specialVarRx)
+    {
+        if (true === $specialVarRx) {
+            $this->specialVarRx = $this->defaultRx;
+        } else {
+            $this->specialVarRx = $specialVarRx;
+        }
+    }
+
+    public function keepImportantComments($bool)
+    {
+        $this->keepImportantComments = (bool) $bool;
+    }
+
+    public function filterLoad(AssetInterface $asset)
+    {
+    }
+
+    public function filterDump(AssetInterface $asset)
+    {
+        $parser = new $this->className();
+        $asset->setContent($parser->squeeze(
+            $asset->getContent(),
+            $this->singleLine,
+            $this->keepImportantComments,
+            $this->specialVarRx
+        ));
+    }
+}

lib/private/templatelayout.php

@@ -37,7 +37,7 @@
 use Assetic\Filter\CssImportFilter;
 use Assetic\Filter\CssMinFilter;
 use Assetic\Filter\CssRewriteFilter;
-use Assetic\Filter\JSMinFilter;
+use OC\Assetic\JSqueeze2Filter; // see note in jsqueeze2filter.php
 use OC\Assetic\SeparatorFilter; // waiting on upstream
 
 /**
@@ -209,7 +209,7 @@ public function generateAssets() {
 					), $root, $file);
 				}
 				return new FileAsset($root . '/' . $file, array(
-					new JSMinFilter(),
+					new JSqueeze2Filter(),
 					new SeparatorFilter(';')
 				), $root, $file);
 			}, $jsFiles);