core-bundle/src/Resources/contao/dca/tl_files.php
public function deleteFile($row, $href, $label, $title, $icon, $attributes)
	{
		$rootDir = Contao\System::getContainer()->getParameter('kernel.project_dir');
		$path = $rootDir . '/' . urldecode($row['id']);

		if (!is_dir($path))
		{
			return ($this->User->hasAccess('f3', 'fop') || $this->User->hasAccess('f4', 'fop')) ? '<a href="'.$this->addToUrl($href.'&amp;id='.$row['id']).'" title="'.Contao\StringUtil::specialchars($title).'"'.$attributes.'>'.Contao\Image::getHtml($icon, $label).'</a> ' : Contao\Image::getHtml(preg_replace('/\.svg$/i', '_.svg', $icon)).' ';
		}

		$finder = Symfony\Component\Finder\Finder::create()->in($path);

		if ($finder->count() > 0)
		{
			return $this->User->hasAccess('f4', 'fop') ? '<a href="'.$this->addToUrl($href.'&amp;id='.$row['id']).'" title="'.Contao\StringUtil::specialchars($title).'"'.$attributes.'>'.Contao\Image::getHtml($icon, $label).'</a> ' : Contao\Image::getHtml(preg_replace('/\.svg$/i', '_.svg', $icon)).' ';
		}

		return $this->User->hasAccess('f3', 'fop') ? '<a href="'.$this->addToUrl($href.'&amp;id='.$row['id']).'" title="'.Contao\StringUtil::specialchars($title).'"'.$attributes.'>'.Contao\Image::getHtml($icon, $label).'</a> ' : Contao\Image::getHtml(preg_replace('/\.svg$/i', '_.svg', $icon)).' ';
	}
public function deleteFile($row, $href, $label, $title, $icon, $attributes)
	{
		$rootDir = Contao\System::getContainer()->getParameter('kernel.project_dir');
		$path = $rootDir . '/' . urldecode($row['id']);

		if (!is_dir($path))
		{
			return ($this->User->hasAccess('f3', 'fop') || $this->User->hasAccess('f4', 'fop')) ? '<a href="'.$this->addToUrl($href.'&amp;id='.$row['id']).'" title="'.Contao\StringUtil::specialchars($title).'"'.$attributes.'>'.Contao\Image::getHtml($icon, $label).'</a> ' : Contao\Image::getHtml(preg_replace('/\.svg$/i', '_.svg', $icon)).' ';
		}

		$finder = Symfony\Component\Finder\Finder::create()->in($path);

		if ($finder->count() > 0)
		{
			return $this->User->hasAccess('f4', 'fop') ? '<a href="'.$this->addToUrl($href.'&amp;id='.$row['id']).'" title="'.Contao\StringUtil::specialchars($title).'"'.$attributes.'>'.Contao\Image::getHtml($icon, $label).'</a> ' : Contao\Image::getHtml(preg_replace('/\.svg$/i', '_.svg', $icon)).' ';
		}

		return $this->User->hasAccess('f3', 'fop') ? '<a href="'.$this->addToUrl($href.'&amp;id='.$row['id']).'" title="'.Contao\StringUtil::specialchars($title).'"'.$attributes.'>'.Contao\Image::getHtml($icon, $label).'</a> ' : Contao\Image::getHtml(preg_replace('/\.svg$/i', '_.svg', $icon)).' ';
	}
Return the delete file button

@param array  $row
@param string $href
@param string $label
@param string $title
@param string $icon
@param string $attributes

@return string