<?php // -*-php-*-
rcs_id('$Id: ADODB.php,v 1.31 2004-06-16 10:38:59 rurban Exp $');

/*
 Copyright 2002,2004 $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

*/ 

/**
 * Based on PearDB.php. 
 * @author: Lawrence Akka, Reini Urban
 *
 * Now (phpwiki-1.3.10) with adodb-4.22, by Reini Urban:
 * 1) Extended to use all available database backend, not only mysql.
 * 2) It uses the ultra-fast binary adodb extension if loaded.
 * 3) We use FETCH_NUM instead of FETCH_ASSOC (faster and more generic)
 * 4) To support generic iterators which return ASSOC fields, and to support queries with 
 *    variable columns, some trickery was needed to use recordset specific fetchMode.
 *    The first Execute uses the global fetchMode (ASSOC), then it's resetted back to NUM 
 *    and the recordset fetchmode is set to ASSOC.
 * 5) Transaction support, and locking as fallback.
 *
 * ADODB basic differences to PearDB: It pre-fetches the first row into fields, 
 * is dirtier in style, layout and more low-level ("worse is better").
 * It has less needed basic features (modifyQuery, locks, ...), but some more 
 * unneeded features included: paging, monitoring and sessions, and much more drivers.
 * No locking (which PearDB supports in some backends), and sequences are very 
 * bad compared to PearDB.

 * Old Comments, by Lawrence Akka:
 * 1)  ADODB's GetRow() is slightly different from that in PEAR.  It does not 
 *     accept a fetchmode parameter
 *     That doesn't matter too much here, since we only ever use FETCHMODE_ASSOC
 * 2)  No need for ''s around strings in sprintf arguments - qstr puts them 
 *     there automatically
 * 3)  ADODB has a version of GetOne, but it is difficult to use it when 
 *     FETCH_ASSOC is in effect.
 *     Instead, use $rs = Execute($query); $value = $rs->fields["$colname"]
 * 4)  No error handling yet - could use ADOConnection->raiseErrorFn
 * 5)  It used to be faster then PEAR/DB at the beginning of 2002. 
 *     Now at August 2002 PEAR/DB with our own page cache added, 
 *     performance is comparable.
 */

require_once('lib/WikiDB/backend.php');
// Error handling - calls trigger_error.  NB - does not close the connection.  Does it need to?
include_once('lib/WikiDB/adodb/adodb-errorhandler.inc.php');
// include the main adodb file
require_once('lib/WikiDB/adodb/adodb.inc.php');

class WikiDB_backend_ADODB
extends WikiDB_backend
{

    function WikiDB_backend_ADODB ($dbparams) {
        $parsed = parseDSN($dbparams['dsn']);
        $this->_dbh = &ADONewConnection($parsed['phptype']);
        $conn = $this->_dbh->Connect($parsed['hostspec'],$parsed['username'], 
                                     $parsed['password'], $parsed['database']);

        //$this->_dbh->debug = true;
        
        // Since 1.3.10 we use the faster ADODB_FETCH_NUM,
        // with some ASSOC based recordsets.
	$GLOBALS['ADODB_FETCH_MODE'] = ADODB_FETCH_NUM;
        $this->_dbh->SetFetchMode(ADODB_FETCH_NUM);

        // Old comment:
        //  With ADODB_COUNTRECS false it should speed up queries, but:
        //  1)  It only works with PHP >= 4.0.6; and
        //  2)  At the moment, I haven't figured out why the wrong results are returned'
        $GLOBALS['ADODB_COUNTRECS'] = false;

        $prefix = isset($dbparams['prefix']) ? $dbparams['prefix'] : '';
        $this->_table_names
            = array('page_tbl'     => $prefix . 'page',
                    'version_tbl'  => $prefix . 'version',
                    'link_tbl'     => $prefix . 'link',
                    'recent_tbl'   => $prefix . 'recent',
                    'nonempty_tbl' => $prefix . 'nonempty');
        $page_tbl = $this->_table_names['page_tbl'];
        $version_tbl = $this->_table_names['version_tbl'];
        $this->page_tbl_fields = "$page_tbl.id as id, $page_tbl.pagename as pagename, "
            . "$page_tbl.hits as hits, $page_tbl.pagedata as pagedata";
        $this->version_tbl_fields = "$version_tbl.version as version, "
            . "$version_tbl.mtime as mtime, "
            . "$version_tbl.minor_edit as minor_edit, $version_tbl.content as content, "
            . "$version_tbl.versiondata as versiondata";

        $this->_expressions
            = array('maxmajor'     => "MAX(CASE WHEN minor_edit=0 THEN version END)",
                    'maxminor'     => "MAX(CASE WHEN minor_edit<>0 THEN version END)",
                    'maxversion'   => "MAX(version)");
        $this->_lock_count = 0;
    }

    /**
     * Close database connection.
     */
    function close () {
        if (!$this->_dbh)
            return;
        if ($this->_lock_count) {
            trigger_error( "WARNING: database still locked " . '(lock_count = $this->_lock_count)' . "\n<br />",
                          E_USER_WARNING);
        }
//      $this->_dbh->setErrorHandling(PEAR_ERROR_PRINT);	// prevent recursive loops.
        $this->unlock(false,'force');

        $this->_dbh->close();
        $this->_dbh = false;
    }

    /*
     * Fast test for wikipage.
     */
    function is_wiki_page($pagename) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        $row = $dbh->GetRow(sprintf("SELECT $page_tbl.id AS id"
                                    . " FROM $nonempty_tbl, $page_tbl"
                                    . " WHERE $nonempty_tbl.id=$page_tbl.id"
                                    . "   AND pagename=%s",
                                    $dbh->qstr($pagename)));
        return $row ? $row[0] : false;
    }
        
    function get_all_pagenames() {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        $result = $dbh->Execute("SELECT pagename"
                                . " FROM $nonempty_tbl, $page_tbl"
                                . " WHERE $nonempty_tbl.id=$page_tbl.id");
        return $result->GetArray();
    }

    function numPages($filter=false, $exclude='') {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        $result = $dbh->getRow("SELECT count(*)"
                            . " FROM $nonempty_tbl, $page_tbl"
                            . " WHERE $nonempty_tbl.id=$page_tbl.id");
        return $result[0];
    }
    
    /**
     * Read page information from database.
     */
    function get_pagedata($pagename) {
        $dbh = &$this->_dbh;
        $page_tbl = $this->_table_names['page_tbl'];
        $row = $dbh->GetRow(sprintf("SELECT hits,pagedata FROM $page_tbl WHERE pagename=%s",
                                       $dbh->qstr($pagename)));
        return $row ? $this->_extract_page_data($row[1],$row[0]) : false;
    }

    function  _extract_page_data(&$data, $hits) {
        $pagedata = empty($data) ? array() : unserialize($data);
        $pagedata['hits'] = $hits;
        return $pagedata;
    }

    function update_pagedata($pagename, $newdata) {
        $dbh = &$this->_dbh;
        $page_tbl = $this->_table_names['page_tbl'];

        // Hits is the only thing we can update in a fast manner.
        if (count($newdata) == 1 && isset($newdata['hits'])) {
            // Note that this will fail silently if the page does not
            // have a record in the page table.  Since it's just the
            // hit count, who cares?
            $dbh->Execute(sprintf("UPDATE $page_tbl SET hits=%d WHERE pagename=%s",
                                  $newdata['hits'], $dbh->qstr($pagename)));
            return;
        }
	$where = sprintf("pagename=%s",$dbh->qstr($pagename));
        $dbh->BeginTrans( );
        $dbh->RowLock($page_tbl,$where);
        
        $data = $this->get_pagedata($pagename);
        if (!$data) {
            $data = array();
            $this->_get_pageid($pagename, true); // Creates page record
        }
        
        @$hits = (int)$data['hits'];
        unset($data['hits']);

        foreach ($newdata as $key => $val) {
            if ($key == 'hits')
                $hits = (int)$val;
            else if (empty($val))
                unset($data[$key]);
            else
                $data[$key] = $val;
        }
        if ($dbh->Execute(sprintf("UPDATE $page_tbl"
                                  . " SET hits=%d, pagedata=%s"
                                  . " WHERE pagename=%s",
                                  $hits,
                                  $dbh->qstr(serialize($data)),
                                  $dbh->qstr($pagename))))
	    $dbh->CommitTrans( );
	else
	    $dbh->RollbackTrans( );
    }

    function _get_pageid($pagename, $create_if_missing = false) {
        
        $dbh = &$this->_dbh;
        $page_tbl = $this->_table_names['page_tbl'];
        $query = sprintf("SELECT id FROM $page_tbl WHERE pagename=%s",
                         $dbh->qstr($pagename));
        if (! $create_if_missing ) {
            $row = $dbh->GetRow($query);
            return $row ? $row[0] : false;
        }
        $row = $dbh->GetRow($query);
        if (! $row ) {
            if ((substr($dbh->databaseType,0,5) == 'mysql') or isa($dbh,'ADODB_sqlite')) {
                // have auto-incrementing and atomic version
                $rs = $dbh->Execute(sprintf("INSERT INTO $page_tbl"
                                            . " (pagename,hits)"
                			    . " VALUES(%s,0)",
                                            $dbh->qstr($pagename)));
                $id = $dbh->_insertid();
            } else {
                //$id = $dbh->GenID($page_tbl . 'seq');
                // Better generic version than with adodob::genID
                $this->lock(array('page'));
                $dbh->BeginTrans( );
                $dbh->CommitLock($page_tbl);
                $row = $dbh->GetRow("SELECT MAX(id) FROM $page_tbl");
                $id = $row[0] + 1;
                $rs = $dbh->Execute(sprintf("INSERT INTO $page_tbl"
                                            . " (id,pagename,hits)"
                                            . " VALUES (%d,%s,0)",
                                            $id, $dbh->qstr($pagename)));
                if ($rs) $dbh->CommitTrans( );
                else $dbh->RollbackTrans( );
                $this->unlock(array('page'));
            }
        } else {
            $id = $row[0];
        }
        return $id;
    }

    function get_latest_version($pagename) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        $row = $dbh->GetRow(sprintf("SELECT latestversion"
                                    . " FROM $page_tbl, $recent_tbl"
                                    . " WHERE $page_tbl.id=$recent_tbl.id"
                                    . "  AND pagename=%s",
                                    $dbh->qstr($pagename)));
        return $row ? (int)$row[0] : false;
    }

    function get_previous_version($pagename, $version) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        // Use SELECTLIMIT for maximum portability
        $rs = $dbh->SelectLimit(sprintf("SELECT version"
                                        . " FROM $version_tbl, $page_tbl"
                                        . " WHERE $version_tbl.id=$page_tbl.id"
                                        . "  AND pagename=%s"
                                        . "  AND version < %d"
                                        . " ORDER BY version DESC"
                                        ,$dbh->qstr($pagename),
                                        $version),
				1);
        return $rs->fields[0] ? (int)$rs->fields[0] : false;
    }
    
    /**
     * Get version data.
     *
     * @param $version int Which version to get.
     *
     * @return hash The version data, or false if specified version does not
     *              exist.
     */
    function get_versiondata($pagename, $version, $want_content = false) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
                
        assert(is_string($pagename) and $pagename != '');
        assert($version > 0);
        
        // FIXME: optimization: sometimes don't get page data?
        if ($want_content) {
            $fields = $this->page_tbl_fields
                . ', ' . $this->version_tbl_fields;
        } else {
            $fields = $this->page_tbl_fields
                . ", $version_tbl.version as version, $version_tbl.mtime as mtime, "
                . "$version_tbl.minor_edit as minor_edit, $version_tbl.content<>'' as have_content, "
                . "$version_tbl.versiondata as versiondata";
        }
        $row = $dbh->GetRow(sprintf("SELECT $fields"
                                    . " FROM $page_tbl, $version_tbl"
                                    . " WHERE $page_tbl.id=$version_tbl.id"
                                    . "  AND pagename=%s"
                                    . "  AND version=%d",
                                    $dbh->qstr($pagename), $version));
        return $row ? $this->_extract_version_data_num($row, $want_content) : false;
    }

    function _extract_version_data_num(&$row, $want_content) {
        if (!$row)
            return false;

        //$id       &= $row[0];
        //$pagename &= $row[1];
        $data = empty($row[8]) ? array() : unserialize($row[8]);
        $data['mtime']         = $row[5];
        $data['is_minor_edit'] = !empty($row[6]);
        if ($want_content) {
            $data['%content'] = $row[7];
        } else {
            $data['%content'] = !empty($row[7]);
        }
        if (!empty($row[3])) {
            $data['%pagedata'] = $this->_extract_page_data($row[3],$row[2]);
        }
        return $data;
    }

    function _extract_version_data_assoc(&$row) {
        if (!$row)
            return false;

        extract($row);
        $data = empty($versiondata) ? array() : unserialize($versiondata);
        $data['mtime'] = $mtime;
        $data['is_minor_edit'] = !empty($minor_edit);
        if (isset($content))
            $data['%content'] = $content;
        elseif ($have_content)
            $data['%content'] = true;
        else
            $data['%content'] = '';
        if (!empty($pagedata)) {
            $data['%pagedata'] = $this->_extract_page_data($pagedata,$hits);
        }
        return $data;
    }

    /**
     * Create a new revision of a page.
     */
    function set_versiondata($pagename, $version, $data) {
        $dbh = &$this->_dbh;
        $version_tbl = $this->_table_names['version_tbl'];
        
        $minor_edit = (int) !empty($data['is_minor_edit']);
        unset($data['is_minor_edit']);
        
        $mtime = (int)$data['mtime'];
        unset($data['mtime']);
        assert(!empty($mtime));

        @$content = (string) $data['%content'];
        unset($data['%content']);
        unset($data['%pagedata']);
        
        $this->lock(array('page','recent','version','nonempty'));
        $dbh->BeginTrans( );
        $dbh->CommitLock($version_tbl);
        $id = $this->_get_pageid($pagename, true);

        // optimize: mysql can do this with one REPLACE INTO.
        if (substr($dbh->databaseType,0,5) == 'mysql') {
            $rs = $dbh->Execute(sprintf("REPLACE INTO $version_tbl"
                                  . " (id,version,mtime,minor_edit,content,versiondata)"
                                  . " VALUES(%d,%d,%d,%d,%s,%s)",
                                  $id, $version, $mtime, $minor_edit,
                                  $dbh->qstr($content),
                                  $dbh->qstr(serialize($data))));
        } else {
            $dbh->Execute(sprintf("DELETE FROM $version_tbl"
                                  . " WHERE id=%d AND version=%d",
                                  $id, $version));
            $rs = $dbh->Execute(sprintf("INSERT INTO $version_tbl"
                                  . " (id,version,mtime,minor_edit,content,versiondata)"
                                  . " VALUES(%d,%d,%d,%d,%s,%s)",
                                  $id, $version, $mtime, $minor_edit,
                                  $dbh->qstr($content),
                                  $dbh->qstr(serialize($data))));
        }
        $this->_update_recent_table($id);
        $this->_update_nonempty_table($id);
        if ($rs) $dbh->CommitTrans( );
        else $dbh->RollbackTrans( );
        $this->unlock(array('page','recent','version','nonempty'));
    }
    
    /**
     * Delete an old revision of a page.
     */
    function delete_versiondata($pagename, $version) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);

        $this->lock(array('version'));
        if ( ($id = $this->_get_pageid($pagename)) ) {
            $dbh->Execute("DELETE FROM $version_tbl"
                        . " WHERE id=$id AND version=$version");
            $this->_update_recent_table($id);
            // This shouldn't be needed (as long as the latestversion
            // never gets deleted.)  But, let's be safe.
            $this->_update_nonempty_table($id);
        }
        $this->unlock(array('version'));
    }

    /**
     * Delete page from the database.
     */
    function delete_page($pagename) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        
        $this->lock(array('version','recent','nonempty','page','link'));
        if ( ($id = $this->_get_pageid($pagename, false)) ) {
            $dbh->Execute("DELETE FROM $version_tbl  WHERE id=$id");
            $dbh->Execute("DELETE FROM $recent_tbl   WHERE id=$id");
            $dbh->Execute("DELETE FROM $nonempty_tbl WHERE id=$id");
            $dbh->Execute("DELETE FROM $link_tbl     WHERE linkfrom=$id");
            $row = $dbh->GetRow("SELECT COUNT(*) FROM $link_tbl WHERE linkto=$id");
            if ($row and $row[0]) {
                // We're still in the link table (dangling link) so we can't delete this
                // altogether.
                $dbh->Execute("UPDATE $page_tbl SET hits=0, pagedata='' WHERE id=$id");
            }
            else {
                $dbh->Execute("DELETE FROM $page_tbl WHERE id=$id");
            }
            $this->_update_recent_table();
            $this->_update_nonempty_table();
        }
        $this->unlock(array('version','recent','nonempty','page','link'));
    }
            

    // The only thing we might be interested in updating which we can
    // do fast in the flags (minor_edit).   I think the default
    // update_versiondata will work fine...
    //function update_versiondata($pagename, $version, $data) {
    //}

    function set_links($pagename, $links) {
        // Update link table.
        // FIXME: optimize: mysql can do this all in one big INSERT.

        $dbh = &$this->_dbh;
        extract($this->_table_names);

        $this->lock(array('link'));
        $pageid = $this->_get_pageid($pagename, true);

        $dbh->Execute("DELETE FROM $link_tbl WHERE linkfrom=$pageid");

	if ($links) {
            foreach($links as $link) {
                if (isset($linkseen[$link]))
                    continue;
                $linkseen[$link] = true;
                $linkid = $this->_get_pageid($link, true);
                $dbh->Execute("INSERT INTO $link_tbl (linkfrom, linkto)"
                            . " VALUES ($pageid, $linkid)");
            }
	}
        $this->unlock(array('link'));
    }
    
    /**
     * Find pages which link to or are linked from a page.
     */
    function get_links($pagename, $reversed = true) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);

        if ($reversed)
            list($have,$want) = array('linkee', 'linker');
        else
            list($have,$want) = array('linker', 'linkee');

        $qpagename = $dbh->qstr($pagename);
        $dbh->SetFetchMode(ADODB_FETCH_ASSOC);
        // removed ref to FETCH_MODE in next line
        $result = $dbh->Execute("SELECT $want.id as id, $want.pagename as pagename,"
                                . " $want.hits as hits, $want.pagedata as pagedata"
                                . " FROM $link_tbl, $page_tbl AS linker, $page_tbl AS linkee"
                                . " WHERE linkfrom=linker.id AND linkto=linkee.id"
                                . " AND $have.pagename=$qpagename"
                                //. " GROUP BY $want.id"
                                . " ORDER BY $want.pagename");
        $dbh->SetFetchMode(ADODB_FETCH_NUM);
        return new WikiDB_backend_ADODB_iter($this, $result);
    }

    function get_all_pages($include_deleted=false,$sortby = false,$limit = false) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        if ($limit)  $limit = "LIMIT $limit";
        else         $limit = '';
        if ($sortby) $orderby = 'ORDER BY ' . PageList::sortby($sortby,'db');
        else         $orderby = '';
        $dbh->SetFetchMode(ADODB_FETCH_ASSOC);
        if (strstr($orderby,' mtime')) {
            if ($include_deleted) {
                $result = $dbh->Execute("SELECT * FROM $page_tbl, $recent_tbl, $version_tbl"
                                        . " WHERE $page_tbl.id=$recent_tbl.id"
                                        . " AND $page_tbl.id=$version_tbl.id AND latestversion=version"
                                        . " $orderby $limit");
            }
            else {
                $result = $dbh->Execute("SELECT "
                                        . $this->page_tbl_fields
                                        . " FROM $nonempty_tbl, $page_tbl, $recent_tbl, $version_tbl"
                                        . " WHERE $nonempty_tbl.id=$page_tbl.id"
                                        . " AND $page_tbl.id=$recent_tbl.id"
                                        . " AND $page_tbl.id=$version_tbl.id AND latestversion=version"
                                        . " $orderby $limit");
            }
        } else {
            if ($include_deleted) {
                $result = $dbh->Execute("SELECT "
                                        . $this->page_tbl_fields
                                        . " FROM $page_tbl $orderby $limit");
            } else {
                $result = $dbh->Execute("SELECT "
                                        . $this->page_tbl_fields
                                        . " FROM $nonempty_tbl, $page_tbl"
                                        . " WHERE $nonempty_tbl.id=$page_tbl.id"
                                        . " $orderby $limit");
            }
        }
        $dbh->SetFetchMode(ADODB_FETCH_NUM);
        return new WikiDB_backend_ADODB_iter($this, $result);
    }
        
    /**
     * Title search.
     */
    function text_search($search = '', $fullsearch = false) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        
        $table = "$nonempty_tbl, $page_tbl";
        $join_clause = "$nonempty_tbl.id=$page_tbl.id";
        $fields = $this->page_tbl_fields;
        $callback = new WikiMethodCb($this, '_sql_match_clause');
        
        if ($fullsearch) {
            $table .= ", $recent_tbl";
            $join_clause .= " AND $page_tbl.id=$recent_tbl.id";

            $table .= ", $version_tbl";
            $join_clause .= " AND $page_tbl.id=$version_tbl.id AND latestversion=version";

            $fields .= "," . $this->version_tbl_fields;
            $callback = new WikiMethodCb($this, '_fullsearch_sql_match_clause');
        }
        
        $search_clause = $search->makeSqlClause($callback);
        $dbh->SetFetchMode(ADODB_FETCH_ASSOC);
        $result = $dbh->Execute("SELECT $fields FROM $table"
                                . " WHERE $join_clause"
                                . "  AND ($search_clause)"
                                . " ORDER BY pagename");

        $dbh->SetFetchMode(ADODB_FETCH_NUM);
        return new WikiDB_backend_ADODB_iter($this, $result);
    }

    function _sql_match_clause($word) {
        //not sure if we need this.  ADODB may do it for us
        $word = preg_replace('/(?=[%_\\\\])/', "\\", $word);  

        // (we need it for at least % and _ --- they're the wildcard characters
        //  for the LIKE operator, and we need to quote them if we're searching
        //  for literal '%'s or '_'s.  --- I'm not sure about \, but it seems to
        //  work as is.
        $word = $this->_dbh->qstr("%$word%");
        $page_tbl = $this->_table_names['page_tbl'];
        return "LOWER($page_tbl.pagename) LIKE $word";
    }

    function _fullsearch_sql_match_clause($word) {
        $word = preg_replace('/(?=[%_\\\\])/', "\\", $word);  //not sure if we need this
        // (see above)
        $word = $this->_dbh->qstr("%$word%");
        $page_tbl = $this->_table_names['page_tbl'];
        return "LOWER($page_tbl.pagename) LIKE $word OR content LIKE $word";
    }

    /**
     * Find highest or lowest hit counts.
     */
    function most_popular($limit=0,$sortby = '') {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        $order = "DESC";
        if ($limit < 0){ 
            $order = "ASC"; 
            $limit = -$limit;
            $where = "";
        } else {
            $where = " AND hits > 0";
        }
        if ($sortby) $orderby = " ORDER BY " . PageList::sortby($sortby,'db');
        else         $orderby = " ORDER BY hits $order";
        $limit = $limit ? $limit : -1;

        $dbh->SetFetchMode(ADODB_FETCH_ASSOC);
        $result = $dbh->SelectLimit("SELECT " 
                                    . $this->page_tbl_fields
                                    . " FROM $nonempty_tbl, $page_tbl"
                                    . " WHERE $nonempty_tbl.id=$page_tbl.id"
                                    . $where
                                    . $orderby
                                    , $limit);
        $dbh->SetFetchMode(ADODB_FETCH_NUM);
        return new WikiDB_backend_ADODB_iter($this, $result);
    }

    /**
     * Find recent changes.
     */
    function most_recent($params) {
        $limit = 0;
        $since = 0;
        $include_minor_revisions = false;
        $exclude_major_revisions = false;
        $include_all_revisions = false;
        extract($params);

        $dbh = &$this->_dbh;
        extract($this->_table_names);

        $pick = array();
        if ($since)
            $pick[] = "mtime >= $since";
        
        if ($include_all_revisions) {
            // Include all revisions of each page.
            $table = "$page_tbl, $version_tbl";
            $join_clause = "$page_tbl.id=$version_tbl.id";

            if ($exclude_major_revisions) {
		// Include only minor revisions
                $pick[] = "minor_edit <> 0";
            }
            elseif (!$include_minor_revisions) {
		// Include only major revisions
                $pick[] = "minor_edit = 0";
            }
        }
        else {
            $table = "$page_tbl, $recent_tbl";
            $join_clause = "$page_tbl.id=$recent_tbl.id";
            $table .= ", $version_tbl";
            $join_clause .= " AND $version_tbl.id=$page_tbl.id";
                
            if ($exclude_major_revisions) {
                // Include only most recent minor revision
                $pick[] = 'version=latestminor';
            }
            elseif (!$include_minor_revisions) {
                // Include only most recent major revision
                $pick[] = 'version=latestmajor';
            }
            else {
                // Include only the latest revision (whether major or minor).
                $pick[] ='version=latestversion';
            }
        }
        $order = "DESC";
        if($limit < 0){
            $order = "ASC";
            $limit = -$limit;
        }
        $limit = $limit ? $limit : -1;
        $where_clause = $join_clause;
        if ($pick)
            $where_clause .= " AND " . join(" AND ", $pick);

        // FIXME: use SQL_BUFFER_RESULT for mysql?
        // Use SELECTLIMIT for portability
        $dbh->SetFetchMode(ADODB_FETCH_ASSOC);
        $result = $dbh->SelectLimit("SELECT "
                                    . $this->page_tbl_fields . ", " . $this->version_tbl_fields
                                    . " FROM $table"
                                    . " WHERE $where_clause"
                                    . " ORDER BY mtime $order",
                                    $limit);
        $dbh->SetFetchMode(ADODB_FETCH_NUM);
        //$result->fields['version'] = $result->fields[6];
        return new WikiDB_backend_ADODB_iter($this, $result);
    }

    /**
     * Rename page in the database.
     */
    function rename_page($pagename, $to) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        
        $this->lock(array('page'));
        if ( ($id = $this->_get_pageid($pagename, false)) ) {
            if ($new = $this->_get_pageid($to, false)) {
                //cludge alert!
                //this page does not exist (already verified before), but exists in the page table.
                //so we delete this page.
                $dbh->query(sprintf("DELETE FROM $page_tbl WHERE id=$id",
                                    $dbh->qstr($to)));
            }
            $dbh->query(sprintf("UPDATE $page_tbl SET pagename=%s WHERE id=$id",
                                $dbh->qstr($to)));
        }
        $this->unlock(array('page'));
        return $id;
    }

    function _update_recent_table($pageid = false) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);
        extract($this->_expressions);

        $pageid = (int)$pageid;

        // optimize: mysql can do this with one REPLACE INTO.
        if (substr($dbh->databaseType,0,5) == 'mysql') {
            $dbh->Execute("REPLACE INTO $recent_tbl"
                          . " (id, latestversion, latestmajor, latestminor)"
                          . " SELECT id, $maxversion, $maxmajor, $maxminor"
                          . " FROM $version_tbl"
                          . ( $pageid ? " WHERE id=$pageid" : "")
                          . " GROUP BY id" );
        } else {
            $this->lock(array('recent'));
            $dbh->Execute("DELETE FROM $recent_tbl"
                      . ( $pageid ? " WHERE id=$pageid" : ""));
            $dbh->Execute( "INSERT INTO $recent_tbl"
                           . " (id, latestversion, latestmajor, latestminor)"
                           . " SELECT id, $maxversion, $maxmajor, $maxminor"
                           . " FROM $version_tbl"
                           . ( $pageid ? " WHERE id=$pageid" : "")
                           . " GROUP BY id" );
            $this->unlock(array('recent'));
        }
    }

    function _update_nonempty_table($pageid = false) {
        $dbh = &$this->_dbh;
        extract($this->_table_names);

        $pageid = (int)$pageid;

        // optimize: mysql can do this with one REPLACE INTO.
        if (substr($dbh->databaseType,0,5) == 'mysql') {
            $dbh->Execute("REPLACE INTO $nonempty_tbl (id)"
                          . " SELECT $recent_tbl.id"
                          . " FROM $recent_tbl, $version_tbl"
                          . " WHERE $recent_tbl.id=$version_tbl.id"
                          . "       AND version=latestversion"
                          . "  AND content<>''"
                          . ( $pageid ? " AND $recent_tbl.id=$pageid" : ""));
        } else {
            $this->lock(array('nonempty'));
            $dbh->Execute("DELETE FROM $nonempty_tbl"
                          . ( $pageid ? " WHERE id=$pageid" : ""));
            $dbh->Execute("INSERT INTO $nonempty_tbl (id)"
                          . " SELECT $recent_tbl.id"
                          . " FROM $recent_tbl, $version_tbl"
                          . " WHERE $recent_tbl.id=$version_tbl.id"
                          . "       AND version=latestversion"
                          . "  AND content<>''"
                          . ( $pageid ? " AND $recent_tbl.id=$pageid" : ""));
            $this->unlock(array('nonempty'));
        }
    }


    /**
     * Grab a write lock on the tables in the SQL database.
     *
     * Calls can be nested.  The tables won't be unlocked until
     * _unlock_database() is called as many times as _lock_database().
     *
     * @access protected
     */
    function lock($tables, $write_lock = true) {
    	$this->_dbh->StartTrans();
        if ($this->_lock_count++ == 0) {
            $this->_current_lock = $tables;
            $this->_lock_tables($tables, $write_lock);
        }
    }

    /**
     * Overridden by non-transaction safe backends.
     */
    function _lock_tables($tables, $write_lock) {
        return $this->_current_lock;
    }
    
    /**
     * Release a write lock on the tables in the SQL database.
     *
     * @access protected
     *
     * @param $force boolean Unlock even if not every call to lock() has been matched
     * by a call to unlock().
     *
     * @see _lock_database
     */
    function unlock($tables = false, $force = false) {
        if ($this->_lock_count == 0) {
            $this->_dbh->CompleteTrans(! $force);
            $this->_current_lock = false;
            return;
        }
        if (--$this->_lock_count <= 0 || $force) {
            $this->_unlock_tables($tables);
            $this->_current_lock = false;
            $this->_lock_count = 0;
        }
    	$this->_dbh->CompleteTrans(! $force);
    }

    /**
     * overridden by non-transaction safe backends
     */
    function _unlock_tables($tables, $write_lock) {
        return;
    }

    /* some variables and functions for DB backend abstraction (action=upgrade) */
    function database () {
        return $this->_dbh->database;
    }
    function backendType() {
        return $this->_dbh->databaseType;
    }
    function connection() {
        return $this->_dbh->_connectionID;
    }

    function listOfTables() {
        return $this->_dbh->MetaTables();
    }
    function listOfFields($database,$table) {
        $field_list = array();
        foreach ($this->_dbh->MetaColumns($table,false) as $field) {
            $field_list[] = $field->name;
        }
        return $field_list;
    }

};

class WikiDB_backend_ADODB_generic_iter
extends WikiDB_backend_iterator
{
    function WikiDB_backend_ADODB_generic_iter(&$backend, &$query_result) {
        $this->_backend = &$backend;
        $this->_result = $query_result;
    }
    
    function count() {
        if (!$this->_result) {
            return false;
        }
        return $this->_result->numRows();
    }

    function next() {
        $result = &$this->_result;
        $backend = &$this->_backend;
        if (!$result || $result->EOF) {
            $this->free();
            return false;
        }
        if (substr($backend->_dbh->databaseType,0,5) == 'mysql')
            $result->fetchMode = 1;
        else
            $result->fetchMode = 2;
        $record = $result->fields;
        if (isset($record[0])) {
            $record = $result->GetRowAssoc(2);
        } else {
            $record = $result->fields;
        }
        $result->MoveNext();
        return $record;
    }

    function free () {
        if ($this->_result) {
            $this->_result->Close();
            $this->_result = false;
        }
    }
}

class WikiDB_backend_ADODB_iter
extends WikiDB_backend_ADODB_generic_iter
{
    function next() {
        $result = &$this->_result;
        $backend = &$this->_backend;
        if (!$result || $result->EOF) {
            $this->free();
            return false;
        }
        if (substr($backend->_dbh->databaseType,0,5) == 'mysql')
            $result->fetchMode = 1;
        else
            $result->fetchMode = 2;
        $record = $result->fields;
        if (isset($record[0])) {
            $record = $result->GetRowAssoc(2);
        } else {
            $record = $result->fields;
        }
        $result->MoveNext();
        
        $pagedata = $backend->_extract_page_data($record['pagedata'], $record['hits']);
        $rec = array('pagename' => $record['pagename'],
                     'pagedata' => $pagedata);
        if (!empty($record['version'])) {
            $rec['versiondata'] = $backend->_extract_version_data_assoc($record);
            $rec['version'] = $record['version'];
        }
        return $rec;
    }
}

// Following function taken from adodb-pear.inc.php.  
// Eventually, change index.php to provide the relevant information
// directly?
    /**
     * Parse a data source name
     *
     * @param $dsn string Data Source Name to be parsed
     *
     * @return array an associative array with the following keys:
     *
     *  phptype: Database backend used in PHP (mysql, odbc etc.)
     *  dbsyntax: Database used with regards to SQL syntax etc.
     *  protocol: Communication protocol to use (tcp, unix etc.)
     *  hostspec: Host specification (hostname[:port])
     *  database: Database to use on the DBMS server
     *  username: User name for login
     *  password: Password for login
     *
     * The format of the supplied DSN is in its fullest form:
     *
     *  phptype(dbsyntax)://username:password@protocol+hostspec/database
     *
     * Most variations are allowed:
     *
     *  phptype://username:password@protocol+hostspec:110//usr/db_file.db
     *  phptype://username:password@hostspec/database_name
     *  phptype://username:password@hostspec
     *  phptype://username@hostspec
     *  phptype://hostspec/database
     *  phptype://hostspec
     *  phptype(dbsyntax)
     *  phptype
     *
     * @author Tomas V.V.Cox <cox@idecnet.com>
     */
    function parseDSN($dsn) {
        if (is_array($dsn)) {
            return $dsn;
        }

        $parsed = array(
            'phptype'  => false,
            'dbsyntax' => false,
            'protocol' => false,
            'hostspec' => false,
            'database' => false,
            'username' => false,
            'password' => false
        );

        // Find phptype and dbsyntax
        if (($pos = strpos($dsn, '://')) !== false) {
            $str = substr($dsn, 0, $pos);
            $dsn = substr($dsn, $pos + 3);
        } else {
            $str = $dsn;
            $dsn = NULL;
        }

        // Get phptype and dbsyntax
        // $str => phptype(dbsyntax)
        if (preg_match('|^(.+?)\((.*?)\)$|', $str, $arr)) {
            $parsed['phptype'] = $arr[1];
            $parsed['dbsyntax'] = (empty($arr[2])) ? $arr[1] : $arr[2];
        } else {
            $parsed['phptype'] = $str;
            $parsed['dbsyntax'] = $str;
        }

        if (empty($dsn)) {
            return $parsed;
        }

        // Get (if found): username and password
        // $dsn => username:password@protocol+hostspec/database
        if (($at = strpos($dsn,'@')) !== false) {
            $str = substr($dsn, 0, $at);
            $dsn = substr($dsn, $at + 1);
            if (($pos = strpos($str, ':')) !== false) {
                $parsed['username'] = urldecode(substr($str, 0, $pos));
                $parsed['password'] = urldecode(substr($str, $pos + 1));
            } else {
                $parsed['username'] = urldecode($str);
            }
        }

        // Find protocol and hostspec
        // $dsn => protocol+hostspec/database
        if (($pos = strpos($dsn, '/')) !== false) {
            $str = substr($dsn, 0, $pos);
            $dsn = substr($dsn, $pos + 1);
        } else {
            $str = $dsn;
            $dsn = NULL;
        }

        // Get protocol + hostspec
        // $str => protocol+hostspec
        if (($pos = strpos($str, '+')) !== false) {
            $parsed['protocol'] = substr($str, 0, $pos);
            $parsed['hostspec'] = urldecode(substr($str, $pos + 1));
        } else {
            $parsed['hostspec'] = urldecode($str);
        }

        // Get dabase if any
        // $dsn => database
        if (!empty($dsn)) {
            $parsed['database'] = $dsn;
        }

        return $parsed;
    }

// $Log: not supported by cvs2svn $
// Revision 1.30  2004/06/07 19:31:31  rurban
// fixed ADOOB upgrade: listOfFields()
//
// Revision 1.29  2004/05/12 10:49:55  rurban
// require_once fix for those libs which are loaded before FileFinder and
//   its automatic include_path fix, and where require_once doesn't grok
//   dirname(__FILE__) != './lib'
// upgrade fix with PearDB
// navbar.tmpl: remove spaces for IE &nbsp; button alignment
//
// Revision 1.28  2004/05/06 19:26:16  rurban
// improve stability, trying to find the InlineParser endless loop on sf.net
//
// remove end-of-zip comments to fix sf.net bug #777278 and probably #859628
//
// Revision 1.27  2004/05/06 17:30:38  rurban
// CategoryGroup: oops, dos2unix eol
// improved phpwiki_version:
//   pre -= .0001 (1.3.10pre: 1030.099)
//   -p1 += .001 (1.3.9-p1: 1030.091)
// improved InstallTable for mysql and generic SQL versions and all newer tables so far.
// abstracted more ADODB/PearDB methods for action=upgrade stuff:
//   backend->backendType(), backend->database(),
//   backend->listOfFields(),
//   backend->listOfTables(),
//
// Revision 1.26  2004/04/26 20:44:35  rurban
// locking table specific for better databases
//
// Revision 1.25  2004/04/20 00:06:04  rurban
// themable paging support
//
// Revision 1.24  2004/04/18 01:34:20  rurban
// protect most_popular from sortby=mtime
//
// Revision 1.23  2004/04/16 14:19:39  rurban
// updated ADODB notes
//

// (c-file-style: "gnu")
// Local Variables:
// mode: php
// tab-width: 8
// c-basic-offset: 4
// c-hanging-comment-ender-p: nil
// indent-tabs-mode: nil
// End:   
?>