file.php

PhpWiki是sourceforge的一个开源项目

<?php // -*-php-*-
rcs_id('$Id: file.php,v 1.22 2004/12/06 19:50:04 rurban Exp $');

/**
 Copyright 1999, 2000, 2001, 2002, 2003 $ThePhpWikiProgrammingTeam

 This file is part of PhpWiki.

 PhpWiki is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 PhpWiki is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with PhpWiki; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/**
 * Backend for handling file storage. 
 *
 * Author: Jochen Kalmbach, [e-mail]
 */

/*
 * TODO: 
 * - Implement "optimize" / "sync" / "check" / "rebuild"
 * - Optimize "get_previous_version"
 * - Optimize "get_links" (reversed = true)
 * - Optimize "get_all_revisions"
 * - Optimize "most_popular" (separate file for "hitcount", 
 *   which contains all pages)
 * - Optimize "most_recent"
 * - What should be done in "lock"/"unlock"/"close" ?
 * - "WikiDB_backend_file_iter": Do I need to return 'version' and 'versiondata' ?
 *
 */

require_once('lib/WikiDB/backend.php');
require_once('lib/ErrorManager.php');

class WikiDB_backend_file
extends WikiDB_backend
{
    var $data_dir;
    var $_dir_names;

    var $_page_data;          // temporarily stores the pagedata (via _loadPageData)
    var $_page_version_data;  // temporarily stores the versiondata (via _loadVersionData)
    var $_latest_versions;    // temporarily stores the latest version-numbers (for every pagename)

    function WikiDB_backend_file( $dbparam )
    {
        $this->data_dir = $dbparam['directory'];
        if (file_exists($this->data_dir) and is_file($this->data_dir))
        	unlink($this->data_dir);
        if (is_dir($this->data_dir) == false) {
            mkdir($this->data_dir, 0755);
        }

        $this->_dir_names
            = array('ver_data'     => $this->data_dir.'/'.'ver_data',
                    'page_data'    => $this->data_dir.'/'.'page_data',
                    'latest_ver'   => $this->data_dir.'/'.'latest_ver',
                    'links'        => $this->data_dir.'/'.'links' );

        foreach ($this->_dir_names as $key => $val) {
        	if (file_exists($val) and is_file($val))
        	    unlink($val);
            if (is_dir($val) == false)
                mkdir($val, 0755);
        }

        $this->_page_data = NULL;
        $this->_page_version_data = NULL;
        $this->_latest_versions = NULL;


    }

    // *********************************************************************
    // common file load / save functions:
    function _pagename2filename($type, $pagename, $version) {
         if ($version == 0)
             return $this->_dir_names[$type].'/'.urlencode($pagename);
         else
             return $this->_dir_names[$type].'/'.urlencode($pagename).'--'.$version;
    }

    function _loadPage($type, $pagename, $version, $set_pagename = true) {
      $filename = $this->_pagename2filename($type, $pagename, $version);
      if (!file_exists($filename)) return NULL;
      if (!filesize($filename)) return array();
      if ($fd = @fopen($filename, "rb")) {
         $locked = flock($fd, 1); # Read lock
         if (!$locked) { 
            ExitWiki("Timeout while obtaining lock. Please try again"); 
         }
         if ($data = fread($fd, filesize($filename))) {
            $pd = unserialize($data);
            if ($set_pagename == true)
                $pd['pagename'] = $pagename;
            if ($version != 0)
                $pd['version'] = $version;
	    if (!is_array($pd))
		ExitWiki(sprintf(gettext("'%s': corrupt file"),
				 htmlspecialchars($filename)));
            else
              return $pd;
	 }	
	 fclose($fd);
      }
      return NULL;
    }

    function _savePage($type, $pagename, $version, $data) {
        $filename = $this->_pagename2filename($type, $pagename, $version);
        if($fd = fopen($filename, 'a+b')) { 
           $locked = flock($fd,2); #Exclusive blocking lock 
           if (!$locked) { 
              ExitWiki("Timeout while obtaining lock. Please try again"); 
           }

           rewind($fd);
           ftruncate($fd, 0);
           $pagedata = serialize($data);
           fwrite($fd, $pagedata); 
           fclose($fd);
        } else {
           ExitWiki("Error while writing page '$pagename'");
        }
    }

    function _removePage($type, $pagename, $version) {
        $filename = $this->_pagename2filename($type, $pagename, $version);
        if (!file_exists($filename)) return NULL;
        $f = @unlink($filename);
        if ($f == false)
            trigger_error("delete file failed: ".$filename." ver: ".$version, E_USER_WARNING);
    }

    // *********************************************************************

    // *********************************************************************
    // Load/Save Version-Data
    function _loadVersionData($pagename, $version) {
        if ($this->_page_version_data != NULL) {
            if ( ($this->_page_version_data['pagename'] == $pagename) && 
                ($this->_page_version_data['version'] == $version) ) {
                return $this->_page_version_data;
             }
        }
        $vd = $this->_loadPage('ver_data', $pagename, $version);
        if ($vd != NULL) {
            $this->_page_version_data = $vd;
            if ( ($this->_page_version_data['pagename'] == $pagename) && 
                ($this->_page_version_data['version'] == $version) ) {
                return $this->_page_version_data;
             }
        }
        return NULL;
    }

    function _saveVersionData($pagename, $version, $data) {
        $this->_savePage('ver_data', $pagename, $version, $data);

        // check if this is a newer version:
        if ($this->_getLatestVersion($pagename) < $version) {
            // write new latest-version-info
            $this->_setLatestVersion($pagename, $version);
        }
    }


    // *********************************************************************
    // Load/Save Page-Data
    function _loadPageData($pagename) {
        if ($this->_page_data != NULL) {
            if ($this->_page_data['pagename'] == $pagename) {
                return $this->_page_data;
             }
        }
        $pd = $this->_loadPage('page_data', $pagename, 0);
        if ($pd != NULL)
            $this->_page_data = $pd;
        if ($this->_page_data != NULL) {
            if ($this->_page_data['pagename'] == $pagename) {
                return $this->_page_data;
             }
        }
        return array();  // no values found
    }

    function _savePageData($pagename, $data) {
        $this->_savePage('page_data', $pagename, 0, $data);
    }

    // *********************************************************************
    // Load/Save Latest-Version
    function _saveLatestVersions() {
        $data = $this->_latest_versions;
        if ($data == NULL)
            $data = array();
        $this->_savePage('latest_ver', 'latest_versions', 0, $data);
    }

    function _setLatestVersion($pagename, $version) {
        // make sure the page version list is loaded:
        $this->_getLatestVersion($pagename);
        if ($version > 0) {
            $this->_getLatestVersion($pagename);
            $this->_latest_versions[$pagename] = $version;
        }
        else {
            // Remove this page from the Latest-Version-List:
            unset($this->_latest_versions[$pagename]);
        }
        $this->_saveLatestVersions();
    }

    function _loadLatestVersions() {
        if ($this->_latest_versions != NULL)
            return;

        $pd = $this->_loadPage('latest_ver', 'latest_versions', 0, false);
        if ($pd != NULL)
            $this->_latest_versions = $pd;
        else
            $this->_latest_versions = array(); // empty array
    }

    function _getLatestVersion($pagename) {
       $this->_loadLatestVersions();
       if (array_key_exists($pagename, $this->_latest_versions) == false)
           return 0; // do version exists
       return $this->_latest_versions[$pagename];
    }


    // *********************************************************************
    // Load/Save Page-Links
    function _loadPageLinks($pagename) {
        $pd = $this->_loadPage('links', $pagename, 0, false);
        if ($pd != NULL)
            return $pd;;
        return array();  // no values found
    }

    function _savePageLinks($pagename, $links) {
        $this->_savePage('links', $pagename, 0, $links);
    }



    /**
     * Get page meta-data from database.
     *
     * @param $pagename string Page name.
     * @return hash
     * Returns a hash containing the page meta-data.
     * Returns an empty array if there is no meta-data for the requested page.
     * Keys which might be present in the hash are:
     * <dl>
     *  <dt> locked  <dd> If the page is locked.
     *  <dt> hits    <dd> The page hit count.
     *  <dt> created <dd> Unix time of page creation. (FIXME: Deprecated: I
     *                    don't think we need this...) 
     * </dl>
     */
    function get_pagedata($pagename) {
        return $this->_loadPageData($pagename);
    }

    /**
     * Update the page meta-data.
     *
     * Set page meta-data.
     *
     * Only meta-data whose keys are preset in $newdata is affected.
     *
     * For example:
     * <pre>
     *   $backend->update_pagedata($pagename, array('locked' => 1)); 
     * </pre>
     * will set the value of 'locked' to 1 for the specified page, but it
     * will not affect the value of 'hits' (or whatever other meta-data
     * may have been stored for the page.)
     *
     * To delete a particular piece of meta-data, set it's value to false.
     * <pre>
     *   $backend->update_pagedata($pagename, array('locked' => false)); 
     * </pre>
     *
     * @param $pagename string Page name.
     * @param $newdata hash New meta-data.
     */
    /**
     * This will create a new page if page being requested does not
     * exist.
     */
    function update_pagedata($pagename, $newdata) {
        $data = $this->get_pagedata($pagename);
        if (count($data) == 0) {
            $this->_savePageData($pagename, $newdata);  // create a new pagedata-file
            return;
        }
        
        foreach ($newdata as $key => $val) {
            if (empty($val))
                unset($data[$key]);
            else
                $data[$key] = $val;
        }
        $this->_savePageData($pagename, $data);  // write new pagedata-file
    }
    

    /**
     * Get the current version number for a page.
     *
     * @param $pagename string Page name.
     * @return int The latest version number for the page.  Returns zero if
     *  no versions of a page exist.
     */
    function get_latest_version($pagename) {
        return $this->_getLatestVersion($pagename);
    }
    
    /**
     * Get preceding version number.
     *
     * @param $pagename string Page name.
     * @param $version int Find version before this one.
     * @return int The version number of the version in the database which
     *  immediately preceeds $version.
     *
     * FIXED: Check if this version really exists!
     */
    function get_previous_version($pagename, $version) {
        $prev = ($version > 0 ? $version - 1 : 0);
    	while ($prev and !file_exists($this->_pagename2filename('ver_data', $pagename, $prev))) {
            $prev--;
    	}
    	return $prev;
    }
    
    /**
     * Get revision meta-data and content.
     *
     * @param $pagename string Page name.
     * @param $version integer Which version to get.
     * @param $want_content boolean
     *  Indicates the caller really wants the page content.  If this
     *  flag is not set, the backend is free to skip fetching of the
     *  page content (as that may be expensive).  If the backend omits
     *  the content, the backend might still want to set the value of
     *  '%content' to the empty string if it knows there's no content.
     *
     * @return hash The version data, or false if specified version does not
     *    exist.
     *
     * Some keys which might be present in the $versiondata hash are:
     * <dl>
     * <dt> %content
     *  <dd> This is a pseudo-meta-data element (since it's actually
     *       the page data, get it?) containing the page content.
     *       If the content was not fetched, this key may not be present.
     * </dl>
     * For description of other version meta-data see WikiDB_PageRevision::get().
     * @see WikiDB_PageRevision::get
     */
    function get_versiondata($pagename, $version, $want_content = false) {
	$vd = $this->_loadVersionData($pagename, $version);
        if ($vd == NULL)
            return false;
        return $vd;
    }

    /**
     * Rename all files for this page
     *
     * @access protected   Via WikiDB
     */
    function rename_page($pagename, $to) {
        $version = _getLatestVersion($pagename);
        foreach ($this->_dir_names as $type => $path) {
            if (is_dir($path)) {
                $filename = $this->_pagename2filename($type, $pagename, $version);
                $new = $this->_pagename2filename($type, $to, $version);
                @rename($filename,$new);
            }
        }
        $this->update_pagedata($pagename, array('pagename' => $to)); 
        return true;
    }

    /**
     * See ADODB for a better delete_page(), which can be undone and is seen in RecentChanges.
     */
    function delete_page($pagename) {
        $this->purge_page($pagename);
    }

    /**
     * Delete page from the database.
     *
     * Delete page (and all it's revisions) from the database.
     *
     * @param $pagename string Page name.
     */
    function purge_page($pagename) {
        $ver = $this->get_latest_version($pagename);
        while ($ver > 0) {
            $this->_removePage('ver_data', $pagename, $ver);
            $ver = $this->get_previous_version($pagename, $ver);
        }
        $this->_removePage('page_data', $pagename, 0);
        $this->_removePage('links', $pagename, 0);
        // remove page from latest_version...