Merge branch 'guessed-extension' into 7.x

Author: taylorotwell

src/Illuminate/Filesystem/Filesystem.php

@@ -7,6 +7,7 @@
 use Illuminate\Contracts\Filesystem\FileNotFoundException;
 use Illuminate\Support\Traits\Macroable;
 use Symfony\Component\Finder\Finder;
+use Symfony\Component\Mime\MimeTypes;
 
 class Filesystem
 {
@@ -312,6 +313,17 @@ public function extension($path)
         return pathinfo($path, PATHINFO_EXTENSION);
     }
 
+    /**
+     * Guess the file extension from the mime-type of a given file.
+     *
+     * @param  string  $path
+     * @return string|null
+     */
+    public function guessExtension($path)
+    {
+        return (new MimeTypes)->getExtensions($this->mimeType($path))[0] ?? null;
+    }
+
     /**
      * Get the file type of a given file.
      *