Database.php

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<?php
# $Id: Database.php,v 1.28 2004/06/15 15:00:52 timstarling Exp $
# This file deals with MySQL interface functions 
# and query specifics/optimisations
#
require_once( "CacheManager.php" );

define( "LIST_COMMA", 0 );
define( "LIST_AND", 1 );
define( "LIST_SET", 2 );

class Database {

#------------------------------------------------------------------------------
# Variables
#------------------------------------------------------------------------------ 
        /* private */ var $mLastQuery = "";
        /* private */ var $mBufferResults = true;
        /* private */ var $mIgnoreErrors = false;
        
        /* private */ var $mServer, $mUser, $mPassword, $mConn, $mDBname;
        /* private */ var $mOut, $mDebug, $mOpened = false;
        
        /* private */ var $mFailFunction; 

#------------------------------------------------------------------------------
# Accessors
#------------------------------------------------------------------------------
        # Set functions
        # These set a variable and return the previous state
        
        # Fail function, takes a Database as a parameter
        # Set to false for default, 1 for ignore errors
        function setFailFunction( $function ) { return wfSetVar( $this->mFailFunction, $function ); }
        
        # Output page, used for reporting errors
        # FALSE means discard output
        function &setOutputPage( &$out ) { $this->mOut =& $out; }
        
        # Boolean, controls output of large amounts of debug information 
        function setDebug( $debug ) { return wfSetVar( $this->mDebug, $debug ); }
        
        # Turns buffering of SQL result sets on (true) or off (false). Default is
        # "on" and it should not be changed without good reasons. 
        function setBufferResults( $buffer ) { return wfSetVar( $this->mBufferResults, $buffer ); }

        # Turns on (false) or off (true) the automatic generation and sending
        # of a "we're sorry, but there has been a database error" page on
        # database errors. Default is on (false). When turned off, the
        # code should use wfLastErrno() and wfLastError() to handle the
        # situation as appropriate.
        function setIgnoreErrors( $ignoreErrors ) { return wfSetVar( $this->mIgnoreErrors, $ignoreErrors ); }
        
        # Get functions
        
        function lastQuery() { return $this->mLastQuery; }
        function isOpen() { return $this->mOpened; }

#------------------------------------------------------------------------------
# Other functions
#------------------------------------------------------------------------------

        function Database()
        {
                global $wgOut;
                # Can't get a reference if it hasn't been set yet
                if ( !isset( $wgOut ) ) {
                        $wgOut = NULL;
                }
                $this->mOut =& $wgOut;
        
        }
        
        /* static */ function newFromParams( $server, $user, $password, $dbName, 
                $failFunction = false, $debug = false, $bufferResults = true, $ignoreErrors = false )
        {
                $db = new Database;
                $db->mFailFunction = $failFunction;
                $db->mIgnoreErrors = $ignoreErrors;
                $db->mDebug = $debug;
                $db->mBufferResults = $bufferResults;
                $db->open( $server, $user, $password, $dbName );
                return $db;
        }
        
        # Usually aborts on failure
        # If the failFunction is set to a non-zero integer, returns success
        function open( $server, $user, $password, $dbName )
        {
                global $wgEmergencyContact;
                
                $this->close();
                $this->mServer = $server;
                $this->mUser = $user;
                $this->mPassword = $password;
                $this->mDBname = $dbName;
                
                $success = false;
                
                @$this->mConn = mysql_connect( $server, $user, $password );
                if ( $dbName != "" ) {
                        if ( $this->mConn !== false ) {
                                $success = @mysql_select_db( $dbName, $this->mConn );
                                if ( !$success ) {
                                        wfDebug( "Error selecting database \"$dbName\": " . $this->lastError() . "\n" );
                                }
                        } else {
                                wfDebug( "DB connection error\n" );
                                wfDebug( "Server: $server, User: $user, Password: " . 
                                        substr( $password, 0, 3 ) . "...\n" );
                                $success = false;
                        }
                } else {
                        # Delay USE query
                        $success = !!$this->mConn;
                }
                
                if ( !$success ) {
                        $this->reportConnectionError();
                        $this->close();
                }
                $this->mOpened = $success;
                return $success;
        }
        
        # Closes a database connection, if it is open
        # Returns success, true if already closed
        function close()
        {
                $this->mOpened = false;
                if ( $this->mConn ) {
                        return mysql_close( $this->mConn );
                } else {
                        return true;
                }
        }
        
        /* private */ function reportConnectionError( $msg = "")
        {
                if ( $this->mFailFunction ) {
                        if ( !is_int( $this->mFailFunction ) ) {
                                $ff = $this->mFailFunction;
                                $ff( $this, mysql_error() );
                        }
                } else {
                        wfEmergencyAbort( $this, mysql_error() );
                }
        }
        
        # Usually aborts on failure
        # If errors are explicitly ignored, returns success
        function query( $sql, $fname = "" )
        {
                global $wgProfiling;
                
                if ( $wgProfiling ) {
                        # generalizeSQL will probably cut down the query to reasonable
                        # logging size most of the time. The substr is really just a sanity check.
                        $profName = "query: " . substr( Database::generalizeSQL( $sql ), 0, 255 ); 
                        wfProfileIn( $profName );
                }
                
                $this->mLastQuery = $sql;
                
                if ( $this->mDebug ) {
                        $sqlx = substr( $sql, 0, 500 );
                        $sqlx = wordwrap(strtr($sqlx,"\t\n","  "));
                        wfDebug( "SQL: $sqlx\n" );
                }
                if( $this->mBufferResults ) {
                        $ret = mysql_query( $sql, $this->mConn );
                } else {
                        $ret = mysql_unbuffered_query( $sql, $this->mConn );
                }
        
                if ( false === $ret ) {
                        $error = mysql_error( $this->mConn );
                        $errno = mysql_errno( $this->mConn );
                        if( $this->mIgnoreErrors ) {
                                wfDebug("SQL ERROR (ignored): " . $error . "\n");
                        } else {
                                wfDebug("SQL ERROR: " . $error . "\n");
                                if ( $this->mOut ) {
                                        // this calls wfAbruptExit()
                                        $this->mOut->databaseError( $fname, $sql, $error, $errno );                             
                                }
                        }
                }
                
                if ( $wgProfiling ) {
                        wfProfileOut( $profName );
                }
                return $ret;
        }
        
        function freeResult( $res ) {
                if ( !@mysql_free_result( $res ) ) {
                        wfDebugDieBacktrace( "Unable to free MySQL result\n" );
                }
        }
        function fetchObject( $res ) {
                @$row = mysql_fetch_object( $res );
                # FIXME: HACK HACK HACK HACK debug
                if( mysql_errno() ) {
                        wfDebugDieBacktrace( "SQL error: " . htmlspecialchars( mysql_error() ) );
                }
                return $row;
        }
        
        function fetchRow( $res ) {
                @$row = mysql_fetch_array( $res );
                if (mysql_errno() ) {
                        wfDebugDieBacktrace( "SQL error: " . htmlspecialchars( mysql_error() ) );
                }
                return $row;
        }       

        function numRows( $res ) {
                @$n = mysql_num_rows( $res ); 
                if( mysql_errno() ) {
                        wfDebugDieBacktrace( "SQL error: " . htmlspecialchars( mysql_error() ) );
                }
                return $n;
        }
        function numFields( $res ) { return mysql_num_fields( $res ); }
        function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
        function insertId() { return mysql_insert_id( $this->mConn ); }
        function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
        function lastErrno() { return mysql_errno(); }
        function lastError() { return mysql_error(); }
        function affectedRows() { return mysql_affected_rows( $this->mConn ); }
        
        # Simple UPDATE wrapper
        # Usually aborts on failure
        # If errors are explicitly ignored, returns success
        function set( $table, $var, $value, $cond, $fname = "Database::set" )
        {
                $sql = "UPDATE $table SET $var = '" .
                  wfStrencode( $value ) . "' WHERE ($cond)";
                return !!$this->query( $sql, DB_WRITE, $fname );
        }
        
        # Simple SELECT wrapper, returns a single field, input must be encoded
        # Usually aborts on failure
        # If errors are explicitly ignored, returns FALSE on failure
        function get( $table, $var, $cond, $fname = "Database::get" )
        {
                $sql = "SELECT $var FROM $table WHERE ($cond)";
                $result = $this->query( $sql, DB_READ, $fname );
        
                $ret = "";
                if ( mysql_num_rows( $result ) > 0 ) {
                        $s = mysql_fetch_object( $result );
                        $ret = $s->$var;
                        mysql_free_result( $result );
                }
                return $ret;
        }
        
        # More complex SELECT wrapper, single row only
        # Aborts or returns FALSE on error
        # Takes an array of selected variables, and a condition map, which is ANDed
        # e.g. getArray( "cur", array( "cur_id" ), array( "cur_namespace" => 0, "cur_title" => "Astronomy" ) )
        #   would return an object where $obj->cur_id is the ID of the Astronomy article
        function getArray( $table, $vars, $conds, $fname = "Database::getArray" )
        {
                $vars = implode( ",", $vars );
                $where = Database::makeList( $conds, LIST_AND );
                $sql = "SELECT $vars FROM $table WHERE $where LIMIT 1";
                $res = $this->query( $sql, $fname );
                if ( $res === false || !$this->numRows( $res ) ) {
                        return false;
                }
                $obj = $this->fetchObject( $res );
                $this->freeResult( $res );
                return $obj;
        }
        
        # Removes most variables from an SQL query and replaces them with X or N for numbers.
        # It's only slightly flawed. Don't use for anything important.
        /* static */ function generalizeSQL( $sql )
        {       
                # This does the same as the regexp below would do, but in such a way
                # as to avoid crashing php on some large strings.
                # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
        
                $sql = str_replace ( "\\\\", "", $sql);
                $sql = str_replace ( "\\'", "", $sql);
                $sql = str_replace ( "\\\"", "", $sql);
                $sql = preg_replace ("/'.*'/s", "'X'", $sql);
                $sql = preg_replace ('/".*"/s', "'X'", $sql);
        
                # All newlines, tabs, etc replaced by single space
                $sql = preg_replace ( "/\s+/", " ", $sql);
        
                # All numbers => N      
                $sql = preg_replace ('/-?[0-9]+/s', "N", $sql);
        
                return $sql;
        }
        
        # Determines whether a field exists in a table
        # Usually aborts on failure
        # If errors are explicitly ignored, returns NULL on failure
        function fieldExists( $table, $field, $fname = "Database::fieldExists" )
        {
                $res = $this->query( "DESCRIBE $table", DB_READ, $fname );
                if ( !$res ) {
                        return NULL;
                }
                
                $found = false;
                
                while ( $row = $this->fetchObject( $res ) ) {
                        if ( $row->Field == $field ) {
                                $found = true;
                                break;
                        }
                }
                return $found;
        }
        
        # Determines whether an index exists
        # Usually aborts on failure
        # If errors are explicitly ignored, returns NULL on failure
        function indexExists( $table, $index, $fname = "Database::indexExists" ) 
        {
                # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
                # SHOW INDEX should work for 3.x and up:
                # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
                $sql = "SHOW INDEX FROM $table";
                $res = $this->query( $sql, DB_READ, $fname );
                if ( !$res ) {
                        return NULL;
                }
                
                $found = false;
                
                while ( $row = $this->fetchObject( $res ) ) {
                        if ( $row->Key_name == $index ) {
                                $found = true;
                                break;
                        }
                }
                return $found;
        }
        
        function tableExists( $table )
        {
                $old = $this->mIgnoreErrors;
                $this->mIgnoreErrors = true;
                $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
                $this->mIgnoreErrors = $old;
                if( $res ) {
                        $this->freeResult( $res );
                        return true;
                } else {
                        return false;
                }
        }

        function fieldInfo( $table, $field )
        {
                $res = $this->query( "SELECT * FROM $table LIMIT 1" );
                $n = mysql_num_fields( $res );
                for( $i = 0; $i < $n; $i++ ) {
                        $meta = mysql_fetch_field( $res, $i );
                        if( $field == $meta->name ) {
                                return $meta;
                        }
                }
                return false;
        }

        # INSERT wrapper, inserts an array into a table
        # Keys are field names, values are values
        # Usually aborts on failure
        # If errors are explicitly ignored, returns success
        function insertArray( $table, $a, $fname = "Database::insertArray" )
        {
                $sql1 = "INSERT INTO $table (";
                $sql2 = "VALUES (" . Database::makeList( $a );
                $first = true;
                foreach ( $a as $field => $value ) {
                        if ( !$first ) {
                                $sql1 .= ",";
                        }
                        $first = false;
                        $sql1 .= $field;
                }
                $sql = "$sql1) $sql2)";
                return !!$this->query( $sql, $fname );
        }
        
        # A cross between insertArray and getArray, takes a condition array and a SET array
        function updateArray( $table, $values, $conds, $fname = "Database::updateArray" )
        {
                $sql = "UPDATE $table SET " . $this->makeList( $values, LIST_SET );
                $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
                $this->query( $sql, $fname );
        }
        
        # Makes a wfStrencoded list from an array
        # $mode: LIST_COMMA - comma separated, no field names
        #        LIST_AND   - ANDed WHERE clause (without the WHERE)
        #        LIST_SET   - comma separated with field names, like a SET clause
        /* static */ function makeList( $a, $mode = LIST_COMMA )
        {
                $first = true;
                $list = "";
                foreach ( $a as $field => $value ) {
                        if ( !$first ) {
                                if ( $mode == LIST_AND ) {
                                        $list .= " AND ";
                                } else {
                                        $list .= ",";
                                }
                        } else {
                                $first = false;
                        }
                        if ( $mode == LIST_AND || $mode == LIST_SET ) {
                                $list .= "$field=";
                        }
                        if ( !is_numeric( $value ) ) {
                                $list .= "'" . wfStrencode( $value ) . "'";
                        } else {
                                $list .= $value;
                        }
                }
                return $list;
        }
        
        function selectDB( $db ) 
        {
                $this->mDBname = $db;
                mysql_select_db( $db, $this->mConn );
        }

        function startTimer( $timeout )
        {
                global $IP;

                $tid = mysql_thread_id( $this->mConn );
                exec( "php $IP/killthread.php $timeout $tid &>/dev/null &" );
        }

        function stopTimer()
        {
        }

}

#------------------------------------------------------------------------------
# Global functions
#------------------------------------------------------------------------------

/* Standard fail function, called by default when a connection cannot be established
   Displays the file cache if possible */
function wfEmergencyAbort( &$conn, $error ) {
        global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgSiteNotice, $wgOutputEncoding;
        
        if( !headers_sent() ) {
                header( "HTTP/1.0 500 Internal Server Error" );
                header( "Content-type: text/html; charset=$wgOutputEncoding" );
                /* Don't cache error pages!  They cause no end of trouble... */
                header( "Cache-control: none" );
                header( "Pragma: nocache" );
        }
        $msg = $wgSiteNotice;
        if($msg == "") $msg = wfMsgNoDB( "noconnect", $error );
        $text = $msg;

        if($wgUseFileCache) {
                if($wgTitle) {
                        $t =& $wgTitle;
                } else {
                        if($title) {
                                $t = Title::newFromURL( $title );
                        } elseif (@$_REQUEST['search']) {
                                $search = $_REQUEST['search'];
                                echo wfMsgNoDB( "searchdisabled" );
                                echo wfMsgNoDB( "googlesearch", htmlspecialchars( $search ), $wgInputEncoding );
                                wfAbruptExit();
                        } else {
                                $t = Title::newFromText( wfMsgNoDB( "mainpage" ) );
                        }
                }

                $cache = new CacheManager( $t );
                if( $cache->isFileCached() ) {
                        $msg = "<p style='color: red'><b>$msg<br />\n" .
                                wfMsgNoDB( "cachederror" ) . "</b></p>\n";
                        
                        $tag = "<div id='article'>";
                        $text = str_replace(
                                $tag,
                                $tag . $msg,
                                $cache->fetchPageText() );
                }
        }
        
        echo $text;
        wfAbruptExit();
}

function wfStrencode( $s )
{
        return addslashes( $s );
}

# Ideally we'd be using actual time fields in the db
function wfTimestamp2Unix( $ts ) {
        return gmmktime( ( (int)substr( $ts, 8, 2) ),
                  (int)substr( $ts, 10, 2 ), (int)substr( $ts, 12, 2 ),
                  (int)substr( $ts, 4, 2 ), (int)substr( $ts, 6, 2 ),
                  (int)substr( $ts, 0, 4 ) );
}

function wfUnix2Timestamp( $unixtime ) {
        return gmdate( "YmdHis", $unixtime );
}

function wfTimestampNow() {
        # return NOW
        return gmdate( "YmdHis" );
}

# Sorting hack for MySQL 3, which doesn't use index sorts for DESC
function wfInvertTimestamp( $ts ) {
        return strtr(
                $ts,
                "0123456789",
                "9876543210"
        );
}

function wfLimitResult( $limit, $offset ) {
        return " LIMIT ".(is_numeric($offset)?"{$offset},":"")."{$limit} ";
}

?>

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