wiki.techinc.nl/includes/Cdb.php

154 lines
3.4 KiB
PHP

<?php
/**
* Native CDB file reader and writer
*
* @file
*/
/**
* Read from a CDB file.
* Native and pure PHP implementations are provided.
* http://cr.yp.to/cdb.html
*/
abstract class CdbReader {
/**
* Open a file and return a subclass instance
*/
public static function open( $fileName ) {
if ( self::haveExtension() ) {
return new CdbReader_DBA( $fileName );
} else {
wfDebug( "Warning: no dba extension found, using emulation.\n" );
return new CdbReader_PHP( $fileName );
}
}
/**
* Returns true if the native extension is available
*/
public static function haveExtension() {
if ( !function_exists( 'dba_handlers' ) ) {
return false;
}
$handlers = dba_handlers();
if ( !in_array( 'cdb', $handlers ) || !in_array( 'cdb_make', $handlers ) ) {
return false;
}
return true;
}
/**
* Construct the object and open the file
*/
abstract function __construct( $fileName );
/**
* Close the file. Optional, you can just let the variable go out of scope.
*/
abstract function close();
/**
* Get a value with a given key. Only string values are supported.
*/
abstract public function get( $key );
}
/**
* Write to a CDB file.
* Native and pure PHP implementations are provided.
*/
abstract class CdbWriter {
/**
* Open a writer and return a subclass instance.
* The user must have write access to the directory, for temporary file creation.
*/
public static function open( $fileName ) {
if ( CdbReader::haveExtension() ) {
return new CdbWriter_DBA( $fileName );
} else {
wfDebug( "Warning: no dba extension found, using emulation.\n" );
return new CdbWriter_PHP( $fileName );
}
}
/**
* Create the object and open the file
*/
abstract function __construct( $fileName );
/**
* Set a key to a given value. The value will be converted to string.
*/
abstract public function set( $key, $value );
/**
* Close the writer object. You should call this function before the object
* goes out of scope, to write out the final hashtables.
*/
abstract public function close();
}
/**
* Reader class which uses the DBA extension
*/
class CdbReader_DBA {
var $handle;
function __construct( $fileName ) {
$this->handle = dba_open( $fileName, 'r-', 'cdb' );
if ( !$this->handle ) {
throw new MWException( 'Unable to open CDB file "' . $fileName . '"' );
}
}
function close() {
if( isset($this->handle) )
dba_close( $this->handle );
unset( $this->handle );
}
function get( $key ) {
return dba_fetch( $key, $this->handle );
}
}
/**
* Writer class which uses the DBA extension
*/
class CdbWriter_DBA {
var $handle, $realFileName, $tmpFileName;
function __construct( $fileName ) {
$this->realFileName = $fileName;
$this->tmpFileName = $fileName . '.tmp.' . mt_rand( 0, 0x7fffffff );
$this->handle = dba_open( $this->tmpFileName, 'n', 'cdb_make' );
if ( !$this->handle ) {
throw new MWException( 'Unable to open CDB file for write "' . $fileName . '"' );
}
}
function set( $key, $value ) {
return dba_insert( $key, $value, $this->handle );
}
function close() {
if( isset($this->handle) )
dba_close( $this->handle );
if ( wfIsWindows() ) {
unlink( $this->realFileName );
}
if ( !rename( $this->tmpFileName, $this->realFileName ) ) {
throw new MWException( 'Unable to move the new CDB file into place.' );
}
unset( $this->handle );
}
function __destruct() {
if ( isset( $this->handle ) ) {
$this->close();
}
}
}