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Filename : Registry.php
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<?php
/**
 * PEAR_Registry
 *
 * PHP versions 4 and 5
 *
 * @category   pear
 * @package    PEAR
 * @author     Stig Bakken <ssb@php.net>
 * @author     Tomas V. V. Cox <cox@idecnet.com>
 * @author     Greg Beaver <cellog@php.net>
 * @copyright  1997-2009 The Authors
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @link       http://pear.php.net/package/PEAR
 * @since      File available since Release 0.1
 */

/**
 * for PEAR_Error
 */
require_once 'PEAR.php';
require_once 'PEAR/DependencyDB.php';

define('PEAR_REGISTRY_ERROR_LOCK',         -2);
define('PEAR_REGISTRY_ERROR_FORMAT',       -3);
define('PEAR_REGISTRY_ERROR_FILE',         -4);
define('PEAR_REGISTRY_ERROR_CONFLICT',     -5);
define('PEAR_REGISTRY_ERROR_CHANNEL_FILE', -6);

/**
 * Administration class used to maintain the installed package database.
 * @category   pear
 * @package    PEAR
 * @author     Stig Bakken <ssb@php.net>
 * @author     Tomas V. V. Cox <cox@idecnet.com>
 * @author     Greg Beaver <cellog@php.net>
 * @copyright  1997-2009 The Authors
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @version    Release: 1.10.12
 * @link       http://pear.php.net/package/PEAR
 * @since      Class available since Release 1.4.0a1
 */
class PEAR_Registry extends PEAR
{
    /**
     * File containing all channel information.
     * @var string
     */
    var $channels = '';

    /** Directory where registry files are stored.
     * @var string
     */
    var $statedir = '';

    /** File where the file map is stored
     * @var string
     */
    var $filemap = '';

    /** Directory where registry files for channels are stored.
     * @var string
     */
    var $channelsdir = '';

    /** Name of file used for locking the registry
     * @var string
     */
    var $lockfile = '';

    /** File descriptor used during locking
     * @var resource
     */
    var $lock_fp = null;

    /** Mode used during locking
     * @var int
     */
    var $lock_mode = 0; // XXX UNUSED

    /** Cache of package information.  Structure:
     * array(
     *   'package' => array('id' => ... ),
     *   ... )
     * @var array
     */
    var $pkginfo_cache = array();

    /** Cache of file map.  Structure:
     * array( '/path/to/file' => 'package', ... )
     * @var array
     */
    var $filemap_cache = array();

    /**
     * @var false|PEAR_ChannelFile
     */
    var $_pearChannel;

    /**
     * @var false|PEAR_ChannelFile
     */
    var $_peclChannel;

    /**
     * @var false|PEAR_ChannelFile
     */
    var $_docChannel;

    /**
     * @var PEAR_DependencyDB
     */
    var $_dependencyDB;

    /**
     * @var PEAR_Config
     */
    var $_config;

    /**
     * PEAR_Registry constructor.
     *
     * @param string (optional) PEAR install directory (for .php files)
     * @param PEAR_ChannelFile PEAR_ChannelFile object representing the PEAR channel, if
     *        default values are not desired.  Only used the very first time a PEAR
     *        repository is initialized
     * @param PEAR_ChannelFile PEAR_ChannelFile object representing the PECL channel, if
     *        default values are not desired.  Only used the very first time a PEAR
     *        repository is initialized
     *
     * @access public
     */
    function __construct($pear_install_dir = PEAR_INSTALL_DIR, $pear_channel = false,
                           $pecl_channel = false, $pear_metadata_dir = '')
    {
        parent::__construct();
        $this->setInstallDir($pear_install_dir, $pear_metadata_dir);
        $this->_pearChannel = $pear_channel;
        $this->_peclChannel = $pecl_channel;
        $this->_config      = false;
    }

    function setInstallDir($pear_install_dir = PEAR_INSTALL_DIR, $pear_metadata_dir = '')
    {
        $ds = DIRECTORY_SEPARATOR;
        $this->install_dir = $pear_install_dir;
        if (!$pear_metadata_dir) {
            $pear_metadata_dir = $pear_install_dir;
        }
        $this->channelsdir = $pear_metadata_dir.$ds.'.channels';
        $this->statedir    = $pear_metadata_dir.$ds.'.registry';
        $this->filemap     = $pear_metadata_dir.$ds.'.filemap';
        $this->lockfile    = $pear_metadata_dir.$ds.'.lock';
    }

    function hasWriteAccess()
    {
        if (!file_exists($this->install_dir)) {
            $dir = $this->install_dir;
            while ($dir && $dir != '.') {
                $olddir = $dir;
                $dir    = dirname($dir);
                if ($dir != '.' && file_exists($dir)) {
                    if (is_writeable($dir)) {
                        return true;
                    }

                    return false;
                }

                if ($dir == $olddir) { // this can happen in safe mode
                    return @is_writable($dir);
                }
            }

            return false;
        }

        return is_writeable($this->install_dir);
    }

    function setConfig(&$config, $resetInstallDir = true)
    {
        $this->_config = &$config;
        if ($resetInstallDir) {
            $this->setInstallDir($config->get('php_dir'), $config->get('metadata_dir'));
        }
    }

    function _initializeChannelDirs()
    {
        static $running = false;
        if (!$running) {
            $running = true;
            $ds = DIRECTORY_SEPARATOR;
            if (!is_dir($this->channelsdir) ||
                  !file_exists($this->channelsdir . $ds . 'pear.php.net.reg') ||
                  !file_exists($this->channelsdir . $ds . 'pecl.php.net.reg') ||
                  !file_exists($this->channelsdir . $ds . 'doc.php.net.reg') ||
                  !file_exists($this->channelsdir . $ds . '__uri.reg')) {
                if (!file_exists($this->channelsdir . $ds . 'pear.php.net.reg')) {
                    $pear_channel = $this->_pearChannel;
                    if (!is_a($pear_channel, 'PEAR_ChannelFile') || !$pear_channel->validate()) {
                        if (!class_exists('PEAR_ChannelFile')) {
                            require_once 'PEAR/ChannelFile.php';
                        }

                        $pear_channel = new PEAR_ChannelFile;
                        $pear_channel->setAlias('pear');
                        $pear_channel->setServer('pear.php.net');
                        $pear_channel->setSummary('PHP Extension and Application Repository');
                        $pear_channel->setDefaultPEARProtocols();
                        $pear_channel->setBaseURL('REST1.0', 'http://pear.php.net/rest/');
                        $pear_channel->setBaseURL('REST1.1', 'http://pear.php.net/rest/');
                        $pear_channel->setBaseURL('REST1.3', 'http://pear.php.net/rest/');
                        //$pear_channel->setBaseURL('REST1.4', 'http://pear.php.net/rest/');
                    } else {
                        $pear_channel->setServer('pear.php.net');
                        $pear_channel->setAlias('pear');
                    }

                    $pear_channel->validate();
                    $this->_addChannel($pear_channel);
                }

                if (!file_exists($this->channelsdir . $ds . 'pecl.php.net.reg')) {
                    $pecl_channel = $this->_peclChannel;
                    if (!is_a($pecl_channel, 'PEAR_ChannelFile') || !$pecl_channel->validate()) {
                        if (!class_exists('PEAR_ChannelFile')) {
                            require_once 'PEAR/ChannelFile.php';
                        }

                        $pecl_channel = new PEAR_ChannelFile;
                        $pecl_channel->setAlias('pecl');
                        $pecl_channel->setServer('pecl.php.net');
                        $pecl_channel->setSummary('PHP Extension Community Library');
                        $pecl_channel->setDefaultPEARProtocols();
                        $pecl_channel->setBaseURL('REST1.0', 'http://pecl.php.net/rest/');
                        $pecl_channel->setBaseURL('REST1.1', 'http://pecl.php.net/rest/');
                        $pecl_channel->setValidationPackage('PEAR_Validator_PECL', '1.0');
                    } else {
                        $pecl_channel->setServer('pecl.php.net');
                        $pecl_channel->setAlias('pecl');
                    }

                    $pecl_channel->validate();
                    $this->_addChannel($pecl_channel);
                }

                if (!file_exists($this->channelsdir . $ds . 'doc.php.net.reg')) {
                    $doc_channel = $this->_docChannel;
                    if (!is_a($doc_channel, 'PEAR_ChannelFile') || !$doc_channel->validate()) {
                        if (!class_exists('PEAR_ChannelFile')) {
                            require_once 'PEAR/ChannelFile.php';
                        }

                        $doc_channel = new PEAR_ChannelFile;
                        $doc_channel->setAlias('phpdocs');
                        $doc_channel->setServer('doc.php.net');
                        $doc_channel->setSummary('PHP Documentation Team');
                        $doc_channel->setDefaultPEARProtocols();
                        $doc_channel->setBaseURL('REST1.0', 'http://doc.php.net/rest/');
                        $doc_channel->setBaseURL('REST1.1', 'http://doc.php.net/rest/');
                        $doc_channel->setBaseURL('REST1.3', 'http://doc.php.net/rest/');
                    } else {
                        $doc_channel->setServer('doc.php.net');
                        $doc_channel->setAlias('doc');
                    }

                    $doc_channel->validate();
                    $this->_addChannel($doc_channel);
                }

                if (!file_exists($this->channelsdir . $ds . '__uri.reg')) {
                    if (!class_exists('PEAR_ChannelFile')) {
                        require_once 'PEAR/ChannelFile.php';
                    }

                    $private = new PEAR_ChannelFile;
                    $private->setName('__uri');
                    $private->setDefaultPEARProtocols();
                    $private->setBaseURL('REST1.0', '****');
                    $private->setSummary('Pseudo-channel for static packages');
                    $this->_addChannel($private);
                }
                $this->_rebuildFileMap();
            }

            $running = false;
        }
    }

    function _initializeDirs()
    {
        $ds = DIRECTORY_SEPARATOR;
        // XXX Compatibility code should be removed in the future
        // rename all registry files if any to lowercase
        if (!OS_WINDOWS && file_exists($this->statedir) && is_dir($this->statedir) &&
              $handle = opendir($this->statedir)) {
            $dest = $this->statedir . $ds;
            while (false !== ($file = readdir($handle))) {
                if (preg_match('/^.*[A-Z].*\.reg\\z/', $file)) {
                    rename($dest . $file, $dest . strtolower($file));
                }
            }
            closedir($handle);
        }

        $this->_initializeChannelDirs();
        if (!file_exists($this->filemap)) {
            $this->_rebuildFileMap();
        }
        $this->_initializeDepDB();
    }

    function _initializeDepDB()
    {
        if (!isset($this->_dependencyDB)) {
            static $initializing = false;
            if (!$initializing) {
                $initializing = true;
                if (!$this->_config) { // never used?
                    $file = OS_WINDOWS ? 'pear.ini' : '.pearrc';
                    $this->_config = new PEAR_Config($this->statedir . DIRECTORY_SEPARATOR .
                        $file);
                    $this->_config->setRegistry($this);
                    $this->_config->set('php_dir', $this->install_dir);
                }

                $this->_dependencyDB = &PEAR_DependencyDB::singleton($this->_config);
                if (PEAR::isError($this->_dependencyDB)) {
                    // attempt to recover by removing the dep db
                    if (file_exists($this->_config->get('metadata_dir', null, 'pear.php.net') .
                        DIRECTORY_SEPARATOR . '.depdb')) {
                        @unlink($this->_config->get('metadata_dir', null, 'pear.php.net') .
                            DIRECTORY_SEPARATOR . '.depdb');
                    }

                    $this->_dependencyDB = &PEAR_DependencyDB::singleton($this->_config);
                    if (PEAR::isError($this->_dependencyDB)) {
                        echo $this->_dependencyDB->getMessage();
                        echo 'Unrecoverable error';
                        exit(1);
                    }
                }

                $initializing = false;
            }
        }
    }

    /**
     * PEAR_Registry destructor.  Makes sure no locks are forgotten.
     *
     * @access private
     */
    function _PEAR_Registry()
    {
        parent::_PEAR();
        if (is_resource($this->lock_fp)) {
            $this->_unlock();
        }
    }

    /**
     * Make sure the directory where we keep registry files exists.
     *
     * @return bool TRUE if directory exists, FALSE if it could not be
     * created
     *
     * @access private
     */
    function _assertStateDir($channel = false)
    {
        if ($channel && $this->_getChannelFromAlias($channel) != 'pear.php.net') {
            return $this->_assertChannelStateDir($channel);
        }

        static $init = false;
        if (!file_exists($this->statedir)) {
            if (!$this->hasWriteAccess()) {
                return false;
            }

            require_once 'System.php';
            if (!System::mkdir(array('-p', $this->statedir))) {
                return $this->raiseError("could not create directory '{$this->statedir}'");
            }
            $init = true;
        } elseif (!is_dir($this->statedir)) {
            return $this->raiseError('Cannot create directory ' . $this->statedir . ', ' .
                'it already exists and is not a directory');
        }

        $ds = DIRECTORY_SEPARATOR;
        if (!file_exists($this->channelsdir)) {
            if (!file_exists($this->channelsdir . $ds . 'pear.php.net.reg') ||
                  !file_exists($this->channelsdir . $ds . 'pecl.php.net.reg') ||
                  !file_exists($this->channelsdir . $ds . 'doc.php.net.reg') ||
                  !file_exists($this->channelsdir . $ds . '__uri.reg')) {
                $init = true;
            }
        } elseif (!is_dir($this->channelsdir)) {
            return $this->raiseError('Cannot create directory ' . $this->channelsdir . ', ' .
                'it already exists and is not a directory');
        }

        if ($init) {
            static $running = false;
            if (!$running) {
                $running = true;
                $this->_initializeDirs();
                $running = false;
                $init = false;
            }
        } else {
            $this->_initializeDepDB();
        }

        return true;
    }

    /**
     * Make sure the directory where we keep registry files exists for a non-standard channel.
     *
     * @param string channel name
     * @return bool TRUE if directory exists, FALSE if it could not be
     * created
     *
     * @access private
     */
    function _assertChannelStateDir($channel)
    {
        $ds = DIRECTORY_SEPARATOR;
        if (!$channel || $this->_getChannelFromAlias($channel) == 'pear.php.net') {
            if (!file_exists($this->channelsdir . $ds . 'pear.php.net.reg')) {
                $this->_initializeChannelDirs();
            }
            return $this->_assertStateDir($channel);
        }

        $channelDir = $this->_channelDirectoryName($channel);
        if (!is_dir($this->channelsdir) ||
              !file_exists($this->channelsdir . $ds . 'pear.php.net.reg')) {
            $this->_initializeChannelDirs();
        }

        if (!file_exists($channelDir)) {
            if (!$this->hasWriteAccess()) {
                return false;
            }

            require_once 'System.php';
            if (!System::mkdir(array('-p', $channelDir))) {
                return $this->raiseError("could not create directory '" . $channelDir .
                    "'");
            }
        } elseif (!is_dir($channelDir)) {
            return $this->raiseError("could not create directory '" . $channelDir .
                "', already exists and is not a directory");
        }

        return true;
    }

    /**
     * Make sure the directory where we keep registry files for channels exists
     *
     * @return bool TRUE if directory exists, FALSE if it could not be
     * created
     *
     * @access private
     */
    function _assertChannelDir()
    {
        if (!file_exists($this->channelsdir)) {
            if (!$this->hasWriteAccess()) {
                return false;
            }

            require_once 'System.php';
            if (!System::mkdir(array('-p', $this->channelsdir))) {
                return $this->raiseError("could not create directory '{$this->channelsdir}'");
            }
        } elseif (!is_dir($this->channelsdir)) {
            return $this->raiseError("could not create directory '{$this->channelsdir}" .
                "', it already exists and is not a directory");
        }

        if (!file_exists($this->channelsdir . DIRECTORY_SEPARATOR . '.alias')) {
            if (!$this->hasWriteAccess()) {
                return false;
            }

            require_once 'System.php';
            if (!System::mkdir(array('-p', $this->channelsdir . DIRECTORY_SEPARATOR . '.alias'))) {
                return $this->raiseError("could not create directory '{$this->channelsdir}/.alias'");
            }
        } elseif (!is_dir($this->channelsdir . DIRECTORY_SEPARATOR . '.alias')) {
            return $this->raiseError("could not create directory '{$this->channelsdir}" .
                "/.alias', it already exists and is not a directory");
        }

        return true;
    }

    /**
     * Get the name of the file where data for a given package is stored.
     *
     * @param string channel name, or false if this is a PEAR package
     * @param string package name
     *
     * @return string registry file name
     *
     * @access public
     */
    function _packageFileName($package, $channel = false)
    {
        if ($channel && $this->_getChannelFromAlias($channel) != 'pear.php.net') {
            return $this->_channelDirectoryName($channel) . DIRECTORY_SEPARATOR .
                strtolower($package) . '.reg';
        }

        return $this->statedir . DIRECTORY_SEPARATOR . strtolower($package) . '.reg';
    }

    /**
     * Get the name of the file where data for a given channel is stored.
     * @param string channel name
     * @return string registry file name
     */
    function _channelFileName($channel, $noaliases = false)
    {
        if (!$noaliases) {
            if (file_exists($this->_getChannelAliasFileName($channel))) {
                $channel = implode('', file($this->_getChannelAliasFileName($channel)));
            }
        }
        return $this->channelsdir . DIRECTORY_SEPARATOR . str_replace('/', '_',
            strtolower($channel)) . '.reg';
    }

    /**
     * @param string
     * @return string
     */
    function _getChannelAliasFileName($alias)
    {
        return $this->channelsdir . DIRECTORY_SEPARATOR . '.alias' .
              DIRECTORY_SEPARATOR . str_replace('/', '_', strtolower($alias)) . '.txt';
    }

    /**
     * Get the name of a channel from its alias
     */
    function _getChannelFromAlias($channel)
    {
        if (!$this->_channelExists($channel)) {
            if ($channel == 'pear.php.net') {
                return 'pear.php.net';
            }

            if ($channel == 'pecl.php.net') {
                return 'pecl.php.net';
            }

            if ($channel == 'doc.php.net') {
                return 'doc.php.net';
            }

            if ($channel == '__uri') {
                return '__uri';
            }

            return false;
        }

        $channel = strtolower($channel);
        if (file_exists($this->_getChannelAliasFileName($channel))) {
            // translate an alias to an actual channel
            return implode('', file($this->_getChannelAliasFileName($channel)));
        }

        return $channel;
    }

    /**
     * Get the alias of a channel from its alias or its name
     */
    function _getAlias($channel)
    {
        if (!$this->_channelExists($channel)) {
            if ($channel == 'pear.php.net') {
                return 'pear';
            }

            if ($channel == 'pecl.php.net') {
                return 'pecl';
            }

            if ($channel == 'doc.php.net') {
                return 'phpdocs';
            }

            return false;
        }

        $channel = $this->_getChannel($channel);
        if (PEAR::isError($channel)) {
            return $channel;
        }

        return $channel->getAlias();
    }

    /**
     * Get the name of the file where data for a given package is stored.
     *
     * @param string channel name, or false if this is a PEAR package
     * @param string package name
     *
     * @return string registry file name
     *
     * @access public
     */
    function _channelDirectoryName($channel)
    {
        if (!$channel || $this->_getChannelFromAlias($channel) == 'pear.php.net') {
            return $this->statedir;
        }

        $ch = $this->_getChannelFromAlias($channel);
        if (!$ch) {
            $ch = $channel;
        }

        return $this->statedir . DIRECTORY_SEPARATOR . strtolower('.channel.' .
            str_replace('/', '_', $ch));
    }

    function _openPackageFile($package, $mode, $channel = false)
    {
        if (!$this->_assertStateDir($channel)) {
            return null;
        }

        if (!in_array($mode, array('r', 'rb')) && !$this->hasWriteAccess()) {
            return null;
        }

        $file = $this->_packageFileName($package, $channel);
        if (!file_exists($file) && $mode == 'r' || $mode == 'rb') {
            return null;
        }

        $fp = @fopen($file, $mode);
        if (!$fp) {
            return null;
        }

        return $fp;
    }

    function _closePackageFile($fp)
    {
        fclose($fp);
    }

    function _openChannelFile($channel, $mode)
    {
        if (!$this->_assertChannelDir()) {
            return null;
        }

        if (!in_array($mode, array('r', 'rb')) && !$this->hasWriteAccess()) {
            return null;
        }

        $file = $this->_channelFileName($channel);
        if (!file_exists($file) && $mode == 'r' || $mode == 'rb') {
            return null;
        }

        $fp = @fopen($file, $mode);
        if (!$fp) {
            return null;
        }

        return $fp;
    }

    function _closeChannelFile($fp)
    {
        fclose($fp);
    }

    function _rebuildFileMap()
    {
        if (!class_exists('PEAR_Installer_Role')) {
            require_once 'PEAR/Installer/Role.php';
        }

        $channels = $this->_listAllPackages();
        $files = array();
        foreach ($channels as $channel => $packages) {
            foreach ($packages as $package) {
                $version = $this->_packageInfo($package, 'version', $channel);
                $filelist = $this->_packageInfo($package, 'filelist', $channel);
                if (!is_array($filelist)) {
                    continue;
                }

                foreach ($filelist as $name => $attrs) {
                    if (isset($attrs['attribs'])) {
                        $attrs = $attrs['attribs'];
                    }

                    // it is possible for conflicting packages in different channels to
                    // conflict with data files/doc files
                    if ($name == 'dirtree') {
                        continue;
                    }

                    if (isset($attrs['role']) && !in_array($attrs['role'],
                          PEAR_Installer_Role::getInstallableRoles())) {
                        // these are not installed
                        continue;
                    }

                    if (isset($attrs['role']) && !in_array($attrs['role'],
                          PEAR_Installer_Role::getBaseinstallRoles())) {
                        $attrs['baseinstalldir'] = $package;
                    }

                    if (isset($attrs['baseinstalldir'])) {
                        $file = $attrs['baseinstalldir'].DIRECTORY_SEPARATOR.$name;
                    } else {
                        $file = $name;
                    }

                    $file = preg_replace(',^/+,', '', $file);
                    if ($channel != 'pear.php.net') {
                        if (!isset($files[$attrs['role']])) {
                            $files[$attrs['role']] = array();
                        }
                        $files[$attrs['role']][$file] = array(strtolower($channel),
                            strtolower($package));
                    } else {
                        if (!isset($files[$attrs['role']])) {
                            $files[$attrs['role']] = array();
                        }
                        $files[$attrs['role']][$file] = strtolower($package);
                    }
                }
            }
        }


        $this->_assertStateDir();
        if (!$this->hasWriteAccess()) {
            return false;
        }

        $fp = @fopen($this->filemap, 'wb');
        if (!$fp) {
            return false;
        }

        $this->filemap_cache = $files;
        fwrite($fp, serialize($files));
        fclose($fp);
        return true;
    }

    function _readFileMap()
    {
        if (!file_exists($this->filemap)) {
            return array();
        }

        $fp = @fopen($this->filemap, 'r');
        if (!$fp) {
            return $this->raiseError('PEAR_Registry: could not open filemap "' . $this->filemap . '"', PEAR_REGISTRY_ERROR_FILE, null, null, $php_errormsg);
        }

        clearstatcache();
        $fsize = filesize($this->filemap);
        fclose($fp);
        $data = file_get_contents($this->filemap);
        $tmp = unserialize($data);
        if (!$tmp && $fsize > 7) {
            return $this->raiseError('PEAR_Registry: invalid filemap data', PEAR_REGISTRY_ERROR_FORMAT, null, null, $data);
        }

        $this->filemap_cache = $tmp;
        return true;
    }

    /**
     * Lock the registry.
     *
     * @param integer lock mode, one of LOCK_EX, LOCK_SH or LOCK_UN.
     *                See flock manual for more information.
     *
     * @return bool TRUE on success, FALSE if locking failed, or a
     *              PEAR error if some other error occurs (such as the
     *              lock file not being writable).
     *
     * @access private
     */
    function _lock($mode = LOCK_EX)
    {
        if (stristr(php_uname(), 'Windows 9')) {
            return true;
        }

        if ($mode != LOCK_UN && is_resource($this->lock_fp)) {
            // XXX does not check type of lock (LOCK_SH/LOCK_EX)
            return true;
        }

        if (!$this->_assertStateDir()) {
            if ($mode == LOCK_EX) {
                return $this->raiseError('Registry directory is not writeable by the current user');
            }

            return true;
        }

        $open_mode = 'w';
        // XXX People reported problems with LOCK_SH and 'w'
        if ($mode === LOCK_SH || $mode === LOCK_UN) {
            if (!file_exists($this->lockfile)) {
                touch($this->lockfile);
            }
            $open_mode = 'r';
        }

        if (!is_resource($this->lock_fp)) {
            $this->lock_fp = @fopen($this->lockfile, $open_mode);
        }

        if (!is_resource($this->lock_fp)) {
            $this->lock_fp = null;
            return $this->raiseError("could not create lock file" .
                                     (isset($php_errormsg) ? ": " . $php_errormsg : ""));
        }

        if (!(int)flock($this->lock_fp, $mode)) {
            switch ($mode) {
                case LOCK_SH: $str = 'shared';    break;
                case LOCK_EX: $str = 'exclusive'; break;
                case LOCK_UN: $str = 'unlock';    break;
                default:      $str = 'unknown';   break;
            }

            //is resource at this point, close it on error.
            fclose($this->lock_fp);
            $this->lock_fp = null;
            return $this->raiseError("could not acquire $str lock ($this->lockfile)",
                                     PEAR_REGISTRY_ERROR_LOCK);
        }

        return true;
    }

    function _unlock()
    {
        $ret = $this->_lock(LOCK_UN);
        if (is_resource($this->lock_fp)) {
            fclose($this->lock_fp);
        }

        $this->lock_fp = null;
        return $ret;
    }

    function _packageExists($package, $channel = false)
    {
        return file_exists($this->_packageFileName($package, $channel));
    }

    /**
     * Determine whether a channel exists in the registry
     *
     * @param string Channel name
     * @param bool if true, then aliases will be ignored
     * @return boolean
     */
    function _channelExists($channel, $noaliases = false)
    {
        $a = file_exists($this->_channelFileName($channel, $noaliases));
        if (!$a && $channel == 'pear.php.net') {
            return true;
        }

        if (!$a && $channel == 'pecl.php.net') {
            return true;
        }

        if (!$a && $channel == 'doc.php.net') {
            return true;
        }

        return $a;
    }

    /**
     * Determine whether a mirror exists within the default channel in the registry
     *
     * @param string Channel name
     * @param string Mirror name
     *
     * @return boolean
     */
    function _mirrorExists($channel, $mirror)
    {
        $data = $this->_channelInfo($channel);
        if (!isset($data['servers']['mirror'])) {
            return false;
        }

        foreach ($data['servers']['mirror'] as $m) {
            if ($m['attribs']['host'] == $mirror) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param PEAR_ChannelFile Channel object
     * @param donotuse
     * @param string Last-Modified HTTP tag from remote request
     * @return boolean|PEAR_Error True on creation, false if it already exists
     */
    function _addChannel($channel, $update = false, $lastmodified = false)
    {
        if (!is_a($channel, 'PEAR_ChannelFile')) {
            return false;
        }

        if (!$channel->validate()) {
            return false;
        }

        if (file_exists($this->_channelFileName($channel->getName()))) {
            if (!$update) {
                return false;
            }

            $checker = $this->_getChannel($channel->getName());
            if (PEAR::isError($checker)) {
                return $checker;
            }

            if ($channel->getAlias() != $checker->getAlias()) {
                if (file_exists($this->_getChannelAliasFileName($checker->getAlias()))) {
                    @unlink($this->_getChannelAliasFileName($checker->getAlias()));
                }
            }
        } else {
            if ($update && !in_array($channel->getName(), array('pear.php.net', 'pecl.php.net', 'doc.php.net'))) {
                return false;
            }
        }

        $ret = $this->_assertChannelDir();
        if (PEAR::isError($ret)) {
            return $ret;
        }

        $ret = $this->_assertChannelStateDir($channel->getName());
        if (PEAR::isError($ret)) {
            return $ret;
        }

        if ($channel->getAlias() != $channel->getName()) {
            if (file_exists($this->_getChannelAliasFileName($channel->getAlias())) &&
                  $this->_getChannelFromAlias($channel->getAlias()) != $channel->getName()) {
                $channel->setAlias($channel->getName());
            }

            if (!$this->hasWriteAccess()) {
                return false;
            }

            $fp = @fopen($this->_getChannelAliasFileName($channel->getAlias()), 'w');
            if (!$fp) {
                return false;
            }

            fwrite($fp, $channel->getName());
            fclose($fp);
        }

        if (!$this->hasWriteAccess()) {
            return false;
        }

        $fp = @fopen($this->_channelFileName($channel->getName()), 'wb');
        if (!$fp) {
            return false;
        }

        $info = $channel->toArray();
        if ($lastmodified) {
            $info['_lastmodified'] = $lastmodified;
        } else {
            $info['_lastmodified'] = self::getSourceDateEpoch();
        }

        fwrite($fp, serialize($info));
        fclose($fp);
        return true;
    }

    /**
     * Deletion fails if there are any packages installed from the channel
     * @param string|PEAR_ChannelFile channel name
     * @return boolean|PEAR_Error True on deletion, false if it doesn't exist
     */
    function _deleteChannel($channel)
    {
        if (!is_string($channel)) {
            if (!is_a($channel, 'PEAR_ChannelFile')) {
                return false;
            }

            if (!$channel->validate()) {
                return false;
            }
            $channel = $channel->getName();
        }

        if ($this->_getChannelFromAlias($channel) == '__uri') {
            return false;
        }

        if ($this->_getChannelFromAlias($channel) == 'pecl.php.net') {
            return false;
        }

        if ($this->_getChannelFromAlias($channel) == 'doc.php.net') {
            return false;
        }

        if (!$this->_channelExists($channel)) {
            return false;
        }

        if (!$channel || $this->_getChannelFromAlias($channel) == 'pear.php.net') {
            return false;
        }

        $channel = $this->_getChannelFromAlias($channel);
        if ($channel == 'pear.php.net') {
            return false;
        }

        $test = $this->_listChannelPackages($channel);
        if (count($test)) {
            return false;
        }

        $test = @rmdir($this->_channelDirectoryName($channel));
        if (!$test) {
            return false;
        }

        $file = $this->_getChannelAliasFileName($this->_getAlias($channel));
        if (file_exists($file)) {
            $test = @unlink($file);
            if (!$test) {
                return false;
            }
        }

        $file = $this->_channelFileName($channel);
        $ret = true;
        if (file_exists($file)) {
            $ret = @unlink($file);
        }

        return $ret;
    }

    /**
     * Determine whether a channel exists in the registry
     * @param string Channel Alias
     * @return boolean
     */
    function _isChannelAlias($alias)
    {
        return file_exists($this->_getChannelAliasFileName($alias));
    }

    /**
     * @param string|null
     * @param string|null
     * @param string|null
     * @return array|null
     * @access private
     */
    function _packageInfo($package = null, $key = null, $channel = 'pear.php.net')
    {
        if ($package === null) {
            if ($channel === null) {
                $channels = $this->_listChannels();
                $ret = array();
                foreach ($channels as $channel) {
                    $channel = strtolower($channel);
                    $ret[$channel] = array();
                    $packages = $this->_listPackages($channel);
                    foreach ($packages as $package) {
                        $ret[$channel][] = $this->_packageInfo($package, null, $channel);
                    }
                }

                return $ret;
            }

            $ps = $this->_listPackages($channel);
            if (!count($ps)) {
                return array();
            }
            return array_map(array(&$this, '_packageInfo'),
                             $ps, array_fill(0, count($ps), null),
                             array_fill(0, count($ps), $channel));
        }

        $fp = $this->_openPackageFile($package, 'r', $channel);
        if ($fp === null) {
            return null;
        }

        clearstatcache();
        $this->_closePackageFile($fp);
        $data = file_get_contents($this->_packageFileName($package, $channel));
        $data = unserialize($data);
        if ($key === null) {
            return $data;
        }

        // compatibility for package.xml version 2.0
        if (isset($data['old'][$key])) {
            return $data['old'][$key];
        }

        if (isset($data[$key])) {
            return $data[$key];
        }

        return null;
    }

    /**
     * @param string Channel name
     * @param bool whether to strictly retrieve info of channels, not just aliases
     * @return array|null
     */
    function _channelInfo($channel, $noaliases = false)
    {
        if (!$this->_channelExists($channel, $noaliases)) {
            return null;
        }

        $fp = $this->_openChannelFile($channel, 'r');
        if ($fp === null) {
            return null;
        }

        clearstatcache();
        $this->_closeChannelFile($fp);
        $data = file_get_contents($this->_channelFileName($channel));
        $data = unserialize($data);
        return $data;
    }

    function _listChannels()
    {
        $channellist = array();
        if (!file_exists($this->channelsdir) || !is_dir($this->channelsdir)) {
            return array('pear.php.net', 'pecl.php.net', 'doc.php.net', '__uri');
        }

        $dp = opendir($this->channelsdir);
        while ($ent = readdir($dp)) {
            if ($ent[0] == '.' || substr($ent, -4) != '.reg') {
                continue;
            }

            if ($ent == '__uri.reg') {
                $channellist[] = '__uri';
                continue;
            }

            $channellist[] = str_replace('_', '/', substr($ent, 0, -4));
        }

        closedir($dp);
        if (!in_array('pear.php.net', $channellist)) {
            $channellist[] = 'pear.php.net';
        }

        if (!in_array('pecl.php.net', $channellist)) {
            $channellist[] = 'pecl.php.net';
        }

        if (!in_array('doc.php.net', $channellist)) {
            $channellist[] = 'doc.php.net';
        }


        if (!in_array('__uri', $channellist)) {
            $channellist[] = '__uri';
        }

        natsort($channellist);
        return $channellist;
    }

    function _listPackages($channel = false)
    {
        if ($channel && $this->_getChannelFromAlias($channel) != 'pear.php.net') {
            return $this->_listChannelPackages($channel);
        }

        if (!file_exists($this->statedir) || !is_dir($this->statedir)) {
            return array();
        }

        $pkglist = array();
        $dp = opendir($this->statedir);
        if (!$dp) {
            return $pkglist;
        }

        while ($ent = readdir($dp)) {
            if ($ent[0] == '.' || substr($ent, -4) != '.reg') {
                continue;
            }

            $pkglist[] = substr($ent, 0, -4);
        }
        closedir($dp);
        sort($pkglist);
        return $pkglist;
    }

    function _listChannelPackages($channel)
    {
        $pkglist = array();
        if (!file_exists($this->_channelDirectoryName($channel)) ||
              !is_dir($this->_channelDirectoryName($channel))) {
            return array();
        }

        $dp = opendir($this->_channelDirectoryName($channel));
        if (!$dp) {
            return $pkglist;
        }

        while ($ent = readdir($dp)) {
            if ($ent[0] == '.' || substr($ent, -4) != '.reg') {
                continue;
            }
            $pkglist[] = substr($ent, 0, -4);
        }

        closedir($dp);
        return $pkglist;
    }

    function _listAllPackages()
    {
        $ret = array();
        foreach ($this->_listChannels() as $channel) {
            $ret[$channel] = $this->_listPackages($channel);
        }

        return $ret;
    }

    /**
     * Add an installed package to the registry
     * @param string package name
     * @param array package info (parsed by PEAR_Common::infoFrom*() methods)
     * @return bool success of saving
     * @access private
     */
    function _addPackage($package, $info)
    {
        if ($this->_packageExists($package)) {
            return false;
        }

        $fp = $this->_openPackageFile($package, 'wb');
        if ($fp === null) {
            return false;
        }

        $info['_lastmodified'] = self::getSourceDateEpoch();
        fwrite($fp, serialize($info));
        $this->_closePackageFile($fp);
        if (isset($info['filelist'])) {
            $this->_rebuildFileMap();
        }

        return true;
    }

    /**
     * @param PEAR_PackageFile_v1|PEAR_PackageFile_v2
     * @return bool
     * @access private
     */
    function _addPackage2($info)
    {
        if (!is_a($info, 'PEAR_PackageFile_v1') && !is_a($info, 'PEAR_PackageFile_v2')) {
            return false;
        }

        if (!$info->validate()) {
            if (class_exists('PEAR_Common')) {
                $ui = PEAR_Frontend::singleton();
                if ($ui) {
                    foreach ($info->getValidationWarnings() as $err) {
                        $ui->log($err['message'], true);
                    }
                }
            }
            return false;
        }

        $channel = $info->getChannel();
        $package = $info->getPackage();
        $save = $info;
        if ($this->_packageExists($package, $channel)) {
            return false;
        }

        if (!$this->_channelExists($channel, true)) {
            return false;
        }

        $info = $info->toArray(true);
        if (!$info) {
            return false;
        }

        $fp = $this->_openPackageFile($package, 'wb', $channel);
        if ($fp === null) {
            return false;
        }

        $info['_lastmodified'] = self::getSourceDateEpoch();
        fwrite($fp, serialize($info));
        $this->_closePackageFile($fp);
        $this->_rebuildFileMap();
        return true;
    }

    /**
     * @param string Package name
     * @param array parsed package.xml 1.0
     * @param bool this parameter is only here for BC.  Don't use it.
     * @access private
     */
    function _updatePackage($package, $info, $merge = true)
    {
        $oldinfo = $this->_packageInfo($package);
        if (empty($oldinfo)) {
            return false;
        }

        $fp = $this->_openPackageFile($package, 'w');
        if ($fp === null) {
            return false;
        }

        if (is_object($info)) {
            $info = $info->toArray();
        }
        $info['_lastmodified'] = self::getSourceDateEpoch();

        $newinfo = $info;
        if ($merge) {
            $info = array_merge($oldinfo, $info);
        } else {
            $diff = $info;
        }

        fwrite($fp, serialize($info));
        $this->_closePackageFile($fp);
        if (isset($newinfo['filelist'])) {
            $this->_rebuildFileMap();
        }

        return true;
    }

    /**
     * @param PEAR_PackageFile_v1|PEAR_PackageFile_v2
     * @return bool
     * @access private
     */
    function _updatePackage2($info)
    {
        if (!$this->_packageExists($info->getPackage(), $info->getChannel())) {
            return false;
        }

        $fp = $this->_openPackageFile($info->getPackage(), 'w', $info->getChannel());
        if ($fp === null) {
            return false;
        }

        $save = $info;
        $info = $save->getArray(true);
        $info['_lastmodified'] = self::getSourceDateEpoch();
        fwrite($fp, serialize($info));
        $this->_closePackageFile($fp);
        $this->_rebuildFileMap();
        return true;
    }

    /**
     * @param string Package name
     * @param string Channel name
     * @return PEAR_PackageFile_v1|PEAR_PackageFile_v2|null
     * @access private
     */
    function &_getPackage($package, $channel = 'pear.php.net')
    {
        $info = $this->_packageInfo($package, null, $channel);
        if ($info === null) {
            return $info;
        }

        $a = $this->_config;
        if (!$a) {
            $this->_config = new PEAR_Config;
            $this->_config->set('php_dir', $this->statedir);
        }

        if (!class_exists('PEAR_PackageFile')) {
            require_once 'PEAR/PackageFile.php';
        }

        $pkg = new PEAR_PackageFile($this->_config);
        $pf = &$pkg->fromArray($info);
        return $pf;
    }

    /**
     * @param string channel name
     * @param bool whether to strictly retrieve channel names
     * @return PEAR_ChannelFile|PEAR_Error
     * @access private
     */
    function &_getChannel($channel, $noaliases = false)
    {
        $ch = false;
        if ($this->_channelExists($channel, $noaliases)) {
            $chinfo = $this->_channelInfo($channel, $noaliases);
            if ($chinfo) {
                if (!class_exists('PEAR_ChannelFile')) {
                    require_once 'PEAR/ChannelFile.php';
                }

                $ch = &PEAR_ChannelFile::fromArrayWithErrors($chinfo);
            }
        }

        if ($ch) {
            if ($ch->validate()) {
                return $ch;
            }

            foreach ($ch->getErrors(true) as $err) {
                $message = $err['message'] . "\n";
            }

            $ch = PEAR::raiseError($message);
            return $ch;
        }

        if ($this->_getChannelFromAlias($channel) == 'pear.php.net') {
            // the registry is not properly set up, so use defaults
            if (!class_exists('PEAR_ChannelFile')) {
                require_once 'PEAR/ChannelFile.php';
            }

            $pear_channel = new PEAR_ChannelFile;
            $pear_channel->setServer('pear.php.net');
            $pear_channel->setAlias('pear');
            $pear_channel->setSummary('PHP Extension and Application Repository');
            $pear_channel->setDefaultPEARProtocols();
            $pear_channel->setBaseURL('REST1.0', 'http://pear.php.net/rest/');
            $pear_channel->setBaseURL('REST1.1', 'http://pear.php.net/rest/');
            $pear_channel->setBaseURL('REST1.3', 'http://pear.php.net/rest/');
            return $pear_channel;
        }

        if ($this->_getChannelFromAlias($channel) == 'pecl.php.net') {
            // the registry is not properly set up, so use defaults
            if (!class_exists('PEAR_ChannelFile')) {
                require_once 'PEAR/ChannelFile.php';
            }
            $pear_channel = new PEAR_ChannelFile;
            $pear_channel->setServer('pecl.php.net');
            $pear_channel->setAlias('pecl');
            $pear_channel->setSummary('PHP Extension Community Library');
            $pear_channel->setDefaultPEARProtocols();
            $pear_channel->setBaseURL('REST1.0', 'http://pecl.php.net/rest/');
            $pear_channel->setBaseURL('REST1.1', 'http://pecl.php.net/rest/');
            $pear_channel->setValidationPackage('PEAR_Validator_PECL', '1.0');
            return $pear_channel;
        }

        if ($this->_getChannelFromAlias($channel) == 'doc.php.net') {
            // the registry is not properly set up, so use defaults
            if (!class_exists('PEAR_ChannelFile')) {
                require_once 'PEAR/ChannelFile.php';
            }

            $doc_channel = new PEAR_ChannelFile;
            $doc_channel->setServer('doc.php.net');
            $doc_channel->setAlias('phpdocs');
            $doc_channel->setSummary('PHP Documentation Team');
            $doc_channel->setDefaultPEARProtocols();
            $doc_channel->setBaseURL('REST1.0', 'http://doc.php.net/rest/');
            $doc_channel->setBaseURL('REST1.1', 'http://doc.php.net/rest/');
            $doc_channel->setBaseURL('REST1.3', 'http://doc.php.net/rest/');
            return $doc_channel;
        }


        if ($this->_getChannelFromAlias($channel) == '__uri') {
            // the registry is not properly set up, so use defaults
            if (!class_exists('PEAR_ChannelFile')) {
                require_once 'PEAR/ChannelFile.php';
            }

            $private = new PEAR_ChannelFile;
            $private->setName('__uri');
            $private->setDefaultPEARProtocols();
            $private->setBaseURL('REST1.0', '****');
            $private->setSummary('Pseudo-channel for static packages');
            return $private;
        }

        return $ch;
    }

    /**
     * @param string Package name
     * @param string Channel name
     * @return bool
     */
    function packageExists($package, $channel = 'pear.php.net')
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_packageExists($package, $channel);
        $this->_unlock();
        return $ret;
    }

    // }}}

    // {{{ channelExists()

    /**
     * @param string channel name
     * @param bool if true, then aliases will be ignored
     * @return bool
     */
    function channelExists($channel, $noaliases = false)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_channelExists($channel, $noaliases);
        $this->_unlock();
        return $ret;
    }

    // }}}

    /**
     * @param string channel name mirror is in
     * @param string mirror name
     *
     * @return bool
     */
    function mirrorExists($channel, $mirror)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }

        $ret = $this->_mirrorExists($channel, $mirror);
        $this->_unlock();
        return $ret;
    }

    // {{{ isAlias()

    /**
     * Determines whether the parameter is an alias of a channel
     * @param string
     * @return bool
     */
    function isAlias($alias)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_isChannelAlias($alias);
        $this->_unlock();
        return $ret;
    }

    // }}}
    // {{{ packageInfo()

    /**
     * @param string|null
     * @param string|null
     * @param string
     * @return array|null
     */
    function packageInfo($package = null, $key = null, $channel = 'pear.php.net')
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_packageInfo($package, $key, $channel);
        $this->_unlock();
        return $ret;
    }

    // }}}
    // {{{ channelInfo()

    /**
     * Retrieve a raw array of channel data.
     *
     * Do not use this, instead use {@link getChannel()} for normal
     * operations.  Array structure is undefined in this method
     * @param string channel name
     * @param bool whether to strictly retrieve information only on non-aliases
     * @return array|null|PEAR_Error
     */
    function channelInfo($channel = null, $noaliases = false)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_channelInfo($channel, $noaliases);
        $this->_unlock();
        return $ret;
    }

    // }}}

    /**
     * @param string
     */
    function channelName($channel)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_getChannelFromAlias($channel);
        $this->_unlock();
        return $ret;
    }

    /**
     * @param string
     */
    function channelAlias($channel)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_getAlias($channel);
        $this->_unlock();
        return $ret;
    }
    // {{{ listPackages()

    function listPackages($channel = false)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_listPackages($channel);
        $this->_unlock();
        return $ret;
    }

    // }}}
    // {{{ listAllPackages()

    function listAllPackages()
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_listAllPackages();
        $this->_unlock();
        return $ret;
    }

    // }}}
    // {{{ listChannel()

    function listChannels()
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_listChannels();
        $this->_unlock();
        return $ret;
    }

    // }}}
    // {{{ addPackage()

    /**
     * Add an installed package to the registry
     * @param string|PEAR_PackageFile_v1|PEAR_PackageFile_v2 package name or object
     *               that will be passed to {@link addPackage2()}
     * @param array package info (parsed by PEAR_Common::infoFrom*() methods)
     * @return bool success of saving
     */
    function addPackage($package, $info)
    {
        if (is_object($info)) {
            return $this->addPackage2($info);
        }
        if (PEAR::isError($e = $this->_lock(LOCK_EX))) {
            return $e;
        }
        $ret = $this->_addPackage($package, $info);
        $this->_unlock();
        if ($ret) {
            if (!class_exists('PEAR_PackageFile_v1')) {
                require_once 'PEAR/PackageFile/v1.php';
            }
            $pf = new PEAR_PackageFile_v1;
            $pf->setConfig($this->_config);
            $pf->fromArray($info);
            $this->_dependencyDB->uninstallPackage($pf);
            $this->_dependencyDB->installPackage($pf);
        }
        return $ret;
    }

    // }}}
    // {{{ addPackage2()

    function addPackage2($info)
    {
        if (!is_object($info)) {
            return $this->addPackage($info['package'], $info);
        }
        if (PEAR::isError($e = $this->_lock(LOCK_EX))) {
            return $e;
        }
        $ret = $this->_addPackage2($info);
        $this->_unlock();
        if ($ret) {
            $this->_dependencyDB->uninstallPackage($info);
            $this->_dependencyDB->installPackage($info);
        }
        return $ret;
    }

    // }}}
    // {{{ updateChannel()

    /**
     * For future expandibility purposes, separate this
     * @param PEAR_ChannelFile
     */
    function updateChannel($channel, $lastmodified = null)
    {
        if ($channel->getName() == '__uri') {
            return false;
        }
        return $this->addChannel($channel, $lastmodified, true);
    }

    // }}}
    // {{{ deleteChannel()

    /**
     * Deletion fails if there are any packages installed from the channel
     * @param string|PEAR_ChannelFile channel name
     * @return boolean|PEAR_Error True on deletion, false if it doesn't exist
     */
    function deleteChannel($channel)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_EX))) {
            return $e;
        }

        $ret = $this->_deleteChannel($channel);
        $this->_unlock();
        if ($ret && is_a($this->_config, 'PEAR_Config')) {
            $this->_config->setChannels($this->listChannels());
        }

        return $ret;
    }

    // }}}
    // {{{ addChannel()

    /**
     * @param PEAR_ChannelFile Channel object
     * @param string Last-Modified header from HTTP for caching
     * @return boolean|PEAR_Error True on creation, false if it already exists
     */
    function addChannel($channel, $lastmodified = false, $update = false)
    {
        if (!is_a($channel, 'PEAR_ChannelFile') || !$channel->validate()) {
            return false;
        }

        if (PEAR::isError($e = $this->_lock(LOCK_EX))) {
            return $e;
        }

        $ret = $this->_addChannel($channel, $update, $lastmodified);
        $this->_unlock();
        if (!$update && $ret && is_a($this->_config, 'PEAR_Config')) {
            $this->_config->setChannels($this->listChannels());
        }

        return $ret;
    }

    // }}}
    // {{{ deletePackage()

    function deletePackage($package, $channel = 'pear.php.net')
    {
        if (PEAR::isError($e = $this->_lock(LOCK_EX))) {
            return $e;
        }

        $file = $this->_packageFileName($package, $channel);
        $ret  = file_exists($file) ? @unlink($file) : false;
        $this->_rebuildFileMap();
        $this->_unlock();
        $p = array('channel' => $channel, 'package' => $package);
        $this->_dependencyDB->uninstallPackage($p);
        return $ret;
    }

    // }}}
    // {{{ updatePackage()

    function updatePackage($package, $info, $merge = true)
    {
        if (is_object($info)) {
            return $this->updatePackage2($info, $merge);
        }
        if (PEAR::isError($e = $this->_lock(LOCK_EX))) {
            return $e;
        }
        $ret = $this->_updatePackage($package, $info, $merge);
        $this->_unlock();
        if ($ret) {
            if (!class_exists('PEAR_PackageFile_v1')) {
                require_once 'PEAR/PackageFile/v1.php';
            }
            $pf = new PEAR_PackageFile_v1;
            $pf->setConfig($this->_config);
            $pf->fromArray($this->packageInfo($package));
            $this->_dependencyDB->uninstallPackage($pf);
            $this->_dependencyDB->installPackage($pf);
        }
        return $ret;
    }

    // }}}
    // {{{ updatePackage2()

    function updatePackage2($info)
    {

        if (!is_object($info)) {
            return $this->updatePackage($info['package'], $info, $merge);
        }

        if (!$info->validate(PEAR_VALIDATE_DOWNLOADING)) {
            return false;
        }

        if (PEAR::isError($e = $this->_lock(LOCK_EX))) {
            return $e;
        }

        $ret = $this->_updatePackage2($info);
        $this->_unlock();
        if ($ret) {
            $this->_dependencyDB->uninstallPackage($info);
            $this->_dependencyDB->installPackage($info);
        }

        return $ret;
    }

    // }}}
    // {{{ getChannel()
    /**
     * @param string channel name
     * @param bool whether to strictly return raw channels (no aliases)
     * @return PEAR_ChannelFile|PEAR_Error
     */
    function getChannel($channel, $noaliases = false)
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $ret = $this->_getChannel($channel, $noaliases);
        $this->_unlock();
        if (!$ret) {
            return PEAR::raiseError('Unknown channel: ' . $channel);
        }
        return $ret;
    }

    // }}}
    // {{{ getPackage()
    /**
     * @param string package name
     * @param string channel name
     * @return PEAR_PackageFile_v1|PEAR_PackageFile_v2|null
     */
    function &getPackage($package, $channel = 'pear.php.net')
    {
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        $pf = &$this->_getPackage($package, $channel);
        $this->_unlock();
        return $pf;
    }

    // }}}

    /**
     * Get PEAR_PackageFile_v[1/2] objects representing the contents of
     * a dependency group that are installed.
     *
     * This is used at uninstall-time
     * @param array
     * @return array|false
     */
    function getInstalledGroup($group)
    {
        $ret = array();
        if (isset($group['package'])) {
            if (!isset($group['package'][0])) {
                $group['package'] = array($group['package']);
            }
            foreach ($group['package'] as $package) {
                $depchannel = isset($package['channel']) ? $package['channel'] : '__uri';
                $p = &$this->getPackage($package['name'], $depchannel);
                if ($p) {
                    $save = &$p;
                    $ret[] = &$save;
                }
            }
        }
        if (isset($group['subpackage'])) {
            if (!isset($group['subpackage'][0])) {
                $group['subpackage'] = array($group['subpackage']);
            }
            foreach ($group['subpackage'] as $package) {
                $depchannel = isset($package['channel']) ? $package['channel'] : '__uri';
                $p = &$this->getPackage($package['name'], $depchannel);
                if ($p) {
                    $save = &$p;
                    $ret[] = &$save;
                }
            }
        }
        if (!count($ret)) {
            return false;
        }
        return $ret;
    }

    // {{{ getChannelValidator()
    /**
     * @param string channel name
     * @return PEAR_Validate|false
     */
    function &getChannelValidator($channel)
    {
        $chan = $this->getChannel($channel);
        if (PEAR::isError($chan)) {
            return $chan;
        }
        $val = $chan->getValidationObject();
        return $val;
    }
    // }}}
    // {{{ getChannels()
    /**
     * @param string channel name
     * @return array an array of PEAR_ChannelFile objects representing every installed channel
     */
    function &getChannels()
    {
        $ret = array();
        if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
            return $e;
        }
        foreach ($this->_listChannels() as $channel) {
            $e = &$this->_getChannel($channel);
            if (!$e || PEAR::isError($e)) {
                continue;
            }
            $ret[] = $e;
        }
        $this->_unlock();
        return $ret;
    }

    // }}}
    // {{{ checkFileMap()

    /**
     * Test whether a file or set of files belongs to a package.
     *
     * If an array is passed in
     * @param string|array file path, absolute or relative to the pear
     *                     install dir
     * @param string|array name of PEAR package or array('package' => name, 'channel' =>
     *                     channel) of a package that will be ignored
     * @param string API version - 1.1 will exclude any files belonging to a package
     * @param array private recursion variable
     * @return array|false which package and channel the file belongs to, or an empty
     *                     string if the file does not belong to an installed package,
     *                     or belongs to the second parameter's package
     */
    function checkFileMap($path, $package = false, $api = '1.0', $attrs = false)
    {
        if (is_array($path)) {
            static $notempty;
            if (empty($notempty)) {
                if (!class_exists('PEAR_Installer_Role')) {
                    require_once 'PEAR/Installer/Role.php';
                }
                $notempty = function($a) { return !empty($a); };
            }
            $package = is_array($package) ? array(strtolower($package[0]), strtolower($package[1]))
                : strtolower($package);
            $pkgs = array();
            foreach ($path as $name => $attrs) {
                if (is_array($attrs)) {
                    if (isset($attrs['install-as'])) {
                        $name = $attrs['install-as'];
                    }
                    if (!in_array($attrs['role'], PEAR_Installer_Role::getInstallableRoles())) {
                        // these are not installed
                        continue;
                    }
                    if (!in_array($attrs['role'], PEAR_Installer_Role::getBaseinstallRoles())) {
                        $attrs['baseinstalldir'] = is_array($package) ? $package[1] : $package;
                    }
                    if (isset($attrs['baseinstalldir'])) {
                        $name = $attrs['baseinstalldir'] . DIRECTORY_SEPARATOR . $name;
                    }
                }
                $pkgs[$name] = $this->checkFileMap($name, $package, $api, $attrs);
                if (PEAR::isError($pkgs[$name])) {
                    return $pkgs[$name];
                }
            }
            return array_filter($pkgs, $notempty);
        }
        if (empty($this->filemap_cache)) {
            if (PEAR::isError($e = $this->_lock(LOCK_SH))) {
                return $e;
            }
            $err = $this->_readFileMap();
            $this->_unlock();
            if (PEAR::isError($err)) {
                return $err;
            }
        }
        if (!$attrs) {
            $attrs = array('role' => 'php'); // any old call would be for PHP role only
        }
        if (isset($this->filemap_cache[$attrs['role']][$path])) {
            if ($api >= '1.1' && $this->filemap_cache[$attrs['role']][$path] == $package) {
                return false;
            }
            return $this->filemap_cache[$attrs['role']][$path];
        }
        $l = strlen($this->install_dir);
        if (substr($path, 0, $l) == $this->install_dir) {
            $path = preg_replace('!^'.DIRECTORY_SEPARATOR.'+!', '', substr($path, $l));
        }
        if (isset($this->filemap_cache[$attrs['role']][$path])) {
            if ($api >= '1.1' && $this->filemap_cache[$attrs['role']][$path] == $package) {
                return false;
            }
            return $this->filemap_cache[$attrs['role']][$path];
        }
        return false;
    }

    // }}}
    // {{{ flush()
    /**
     * Force a reload of the filemap
     * @since 1.5.0RC3
     */
    function flushFileMap()
    {
        $this->filemap_cache = null;
        clearstatcache(); // ensure that the next read gets the full, current filemap
    }

    // }}}
    // {{{ apiVersion()
    /**
     * Get the expected API version.  Channels API is version 1.1, as it is backwards
     * compatible with 1.0
     * @return string
     */
    function apiVersion()
    {
        return '1.1';
    }
    // }}}


    /**
     * Parse a package name, or validate a parsed package name array
     * @param string|array pass in an array of format
     *                     array(
     *                      'package' => 'pname',
     *                     ['channel' => 'channame',]
     *                     ['version' => 'version',]
     *                     ['state' => 'state',]
     *                     ['group' => 'groupname'])
     *                     or a string of format
     *                     [channel://][channame/]pname[-version|-state][/group=groupname]
     * @return array|PEAR_Error
     */
    function parsePackageName($param, $defaultchannel = 'pear.php.net')
    {
        $saveparam = $param;
        if (is_array($param)) {
            // convert to string for error messages
            $saveparam = $this->parsedPackageNameToString($param);
            // process the array
            if (!isset($param['package'])) {
                return PEAR::raiseError('parsePackageName(): array $param ' .
                    'must contain a valid package name in index "param"',
                    'package', null, null, $param);
            }
            if (!isset($param['uri'])) {
                if (!isset($param['channel'])) {
                    $param['channel'] = $defaultchannel;
                }
            } else {
                $param['channel'] = '__uri';
            }
        } else {
            $components = @parse_url((string) $param);
            if (isset($components['scheme'])) {
                if ($components['scheme'] == 'http') {
                    // uri package
                    $param = array('uri' => $param, 'channel' => '__uri');
                } elseif($components['scheme'] != 'channel') {
                    return PEAR::raiseError('parsePackageName(): only channel:// uris may ' .
                        'be downloaded, not "' . $param . '"', 'invalid', null, null, $param);
                }
            }
            if (!isset($components['path'])) {
                return PEAR::raiseError('parsePackageName(): array $param ' .
                    'must contain a valid package name in "' . $param . '"',
                    'package', null, null, $param);
            }
            if (isset($components['host'])) {
                // remove the leading "/"
                $components['path'] = substr($components['path'], 1);
            }
            if (!isset($components['scheme'])) {
                if (strpos($components['path'], '/') !== false) {
                    if ($components['path'][0] == '/') {
                        return PEAR::raiseError('parsePackageName(): this is not ' .
                            'a package name, it begins with "/" in "' . $param . '"',
                            'invalid', null, null, $param);
                    }
                    $parts = explode('/', $components['path']);
                    $components['host'] = array_shift($parts);
                    if (count($parts) > 1) {
                        $components['path'] = array_pop($parts);
                        $components['host'] .= '/' . implode('/', $parts);
                    } else {
                        $components['path'] = implode('/', $parts);
                    }
                } else {
                    $components['host'] = $defaultchannel;
                }
            } else {
                if (strpos($components['path'], '/')) {
                    $parts = explode('/', $components['path']);
                    $components['path'] = array_pop($parts);
                    $components['host'] .= '/' . implode('/', $parts);
                }
            }

            if (is_array($param)) {
                $param['package'] = $components['path'];
            } else {
                $param = array(
                    'package' => $components['path']
                    );
                if (isset($components['host'])) {
                    $param['channel'] = $components['host'];
                }
            }
            if (isset($components['fragment'])) {
                $param['group'] = $components['fragment'];
            }
            if (isset($components['user'])) {
                $param['user'] = $components['user'];
            }
            if (isset($components['pass'])) {
                $param['pass'] = $components['pass'];
            }
            if (isset($components['query'])) {
                parse_str($components['query'], $param['opts']);
            }
            // check for extension
            $pathinfo = pathinfo($param['package']);
            if (isset($pathinfo['extension']) &&
                  in_array(strtolower($pathinfo['extension']), array('tgz', 'tar'))) {
                $param['extension'] = $pathinfo['extension'];
                $param['package'] = substr($pathinfo['basename'], 0,
                    strlen($pathinfo['basename']) - 4);
            }
            // check for version
            if (strpos($param['package'], '-')) {
                $test = explode('-', $param['package']);
                if (count($test) != 2) {
                    return PEAR::raiseError('parsePackageName(): only one version/state ' .
                        'delimiter "-" is allowed in "' . $saveparam . '"',
                        'version', null, null, $param);
                }
                list($param['package'], $param['version']) = $test;
            }
        }
        // validation
        $info = $this->channelExists($param['channel']);
        if (PEAR::isError($info)) {
            return $info;
        }
        if (!$info) {
            return PEAR::raiseError('unknown channel "' . $param['channel'] .
                '" in "' . $saveparam . '"', 'channel', null, null, $param);
        }
        $chan = $this->getChannel($param['channel']);
        if (PEAR::isError($chan)) {
            return $chan;
        }
        if (!$chan) {
            return PEAR::raiseError("Exception: corrupt registry, could not " .
                "retrieve channel " . $param['channel'] . " information",
                'registry', null, null, $param);
        }
        $param['channel'] = $chan->getName();
        $validate = $chan->getValidationObject();
        $vpackage = $chan->getValidationPackage();
        // validate package name
        if (!$validate->validPackageName($param['package'], $vpackage['_content'])) {
            return PEAR::raiseError('parsePackageName(): invalid package name "' .
                $param['package'] . '" in "' . $saveparam . '"',
                'package', null, null, $param);
        }
        if (isset($param['group'])) {
            if (!PEAR_Validate::validGroupName($param['group'])) {
                return PEAR::raiseError('parsePackageName(): dependency group "' . $param['group'] .
                    '" is not a valid group name in "' . $saveparam . '"', 'group', null, null,
                    $param);
            }
        }
        if (isset($param['state'])) {
            if (!in_array(strtolower($param['state']), $validate->getValidStates())) {
                return PEAR::raiseError('parsePackageName(): state "' . $param['state']
                    . '" is not a valid state in "' . $saveparam . '"',
                    'state', null, null, $param);
            }
        }
        if (isset($param['version'])) {
            if (isset($param['state'])) {
                return PEAR::raiseError('parsePackageName(): cannot contain both ' .
                    'a version and a stability (state) in "' . $saveparam . '"',
                    'version/state', null, null, $param);
            }
            // check whether version is actually a state
            if (in_array(strtolower($param['version']), $validate->getValidStates())) {
                $param['state'] = strtolower($param['version']);
                unset($param['version']);
            } else {
                if (!$validate->validVersion($param['version'])) {
                    return PEAR::raiseError('parsePackageName(): "' . $param['version'] .
                        '" is neither a valid version nor a valid state in "' .
                        $saveparam . '"', 'version/state', null, null, $param);
                }
            }
        }
        return $param;
    }

    /**
     * @param array
     * @return string
     */
    function parsedPackageNameToString($parsed, $brief = false)
    {
        if (is_string($parsed)) {
            return $parsed;
        }
        if (is_object($parsed)) {
            $p = $parsed;
            $parsed = array(
                'package' => $p->getPackage(),
                'channel' => $p->getChannel(),
                'version' => $p->getVersion(),
            );
        }
        if (isset($parsed['uri'])) {
            return $parsed['uri'];
        }
        if ($brief) {
            if ($channel = $this->channelAlias($parsed['channel'])) {
                return $channel . '/' . $parsed['package'];
            }
        }
        $upass = '';
        if (isset($parsed['user'])) {
            $upass = $parsed['user'];
            if (isset($parsed['pass'])) {
                $upass .= ':' . $parsed['pass'];
            }
            $upass = "$upass@";
        }
        $ret = 'channel://' . $upass . $parsed['channel'] . '/' . $parsed['package'];
        if (isset($parsed['version']) || isset($parsed['state'])) {
            $ver = isset($parsed['version']) ? $parsed['version'] : '';
            $ver .= isset($parsed['state']) ? $parsed['state'] : '';
            $ret .= '-' . $ver;
        }
        if (isset($parsed['extension'])) {
            $ret .= '.' . $parsed['extension'];
        }
        if (isset($parsed['opts'])) {
            $ret .= '?';
            foreach ($parsed['opts'] as $name => $value) {
                $parsed['opts'][$name] = "$name=$value";
            }
            $ret .= implode('&', $parsed['opts']);
        }
        if (isset($parsed['group'])) {
            $ret .= '#' . $parsed['group'];
        }
        return $ret;
    }
}