Piwik\Plugins\CorePluginsAdmin\PluginInstaller::extractPluginFiles PHP Method

    private function extractPluginFiles($pluginZipFile, $pathExtracted)
    {
        $archive = Unzip::factory('PclZip', $pluginZipFile);
        $this->removeFolderIfExists($pathExtracted);
        if (0 == ($pluginFiles = $archive->extract($pathExtracted))) {
            throw new PluginInstallerException(Piwik::translate('CoreUpdater_ExceptionArchiveIncompatible', $archive->errorInfo()));
        }
        if (0 == count($pluginFiles)) {
            throw new PluginInstallerException(Piwik::translate('Plugin Zip File Is Empty'));
        }
    }