root/tags/1.3/wp-admin/includes/file.php

<?php

$wp_file_descriptions = array ('index.php' => __( 'Main Index Template' ), 'style.css' => __( 'Stylesheet' ), 'comments.php' => __( 'Comments' ), 'comments-popup.php' => __( 'Popup Comments' ), 'footer.php' => __( 'Footer' ), 'header.php' => __( 'Header' ), 'sidebar.php' => __( 'Sidebar' ), 'archive.php' => __( 'Archives' ), 'category.php' => __( 'Category Template' ), 'page.php' => __( 'Page Template' ), 'search.php' => __( 'Search Results' ), 'single.php' => __( 'Single Post' ), '404.php' => __( '404 Template' ), 'my-hacks.php' => __( 'my-hacks.php (legacy hacks support)' ), '.htaccess' => __( '.htaccess (for rewrite rules )' ),
    // Deprecated files
    'wp-layout.css' => __( 'Stylesheet' ), 'wp-comments.php' => __( 'Comments Template' ), 'wp-comments-popup.php' => __( 'Popup Comments Template' ));
function get_file_description( $file ) {
    global $wp_file_descriptions;

    if ( isset( $wp_file_descriptions[basename( $file )] ) ) {
        return $wp_file_descriptions[basename( $file )];
    }
    elseif ( file_exists( ABSPATH . $file ) && is_file( ABSPATH . $file ) ) {
        $template_data = implode( '', file( ABSPATH . $file ) );
        if ( preg_match( "|Template Name:(.*)|i", $template_data, $name ))
            return $name[1];
    }

    return basename( $file );
}

function get_home_path() {
    $home = get_option( 'home' );
    if ( $home != '' && $home != get_option( 'siteurl' ) ) {
        $home_path = parse_url( $home );
        $home_path = $home_path['path'];
        $root = str_replace( $_SERVER["PHP_SELF"], '', $_SERVER["SCRIPT_FILENAME"] );
        $home_path = trailingslashit( $root.$home_path );
    } else {
        $home_path = ABSPATH;
    }

    return $home_path;
}

function get_real_file_to_edit( $file ) {
    if ('index.php' == $file || '.htaccess' == $file ) {
        $real_file = get_home_path().$file;
    } else {
        $real_file = ABSPATH.$file;
    }

    return $real_file;
}

function validate_file( $file, $allowed_files = '' ) {
    if ( false !== strpos( $file, './' ))
        return 1;

    if (':' == substr( $file, 1, 1 ))
        return 2;

    if (!empty ( $allowed_files ) && (!in_array( $file, $allowed_files ) ) )
        return 3;

    return 0;
}

function validate_file_to_edit( $file, $allowed_files = '' ) {
    $file = stripslashes( $file );

    $code = validate_file( $file, $allowed_files );

    if (!$code )
        return $file;

    switch ( $code ) {
        case 1 :
            wp_die( __('Sorry, can&#8217;t edit files with ".." in the name. If you are trying to edit a file in your WordPress home directory, you can just type the name of the file in.' ));

        case 2 :
            wp_die( __('Sorry, can&#8217;t call files with their real path.' ));

        case 3 :
            wp_die( __('Sorry, that file cannot be edited.' ));
    }
}

// array wp_handle_upload ( array &file [, array overrides] )
// file: reference to a single element of $_FILES. Call the function once for each uploaded file.
// overrides: an associative array of names=>values to override default variables with extract( $overrides, EXTR_OVERWRITE ).
// On success, returns an associative array of file attributes.
// On failure, returns $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
function wp_handle_upload( &$file, $overrides = false ) {
    // The default error handler.
    if (! function_exists( 'wp_handle_upload_error' ) ) {
        function wp_handle_upload_error( &$file, $message ) {
            return array( 'error'=>$message );
        }
    }

    $file = apply_filters( 'wp_handle_upload_prefilter', $file );

    // You may define your own function and pass the name in $overrides['upload_error_handler']
    $upload_error_handler = 'wp_handle_upload_error';

    // $_POST['action'] must be set and its value must equal $overrides['action'] or this:
    $action = 'wp_handle_upload';

    // Courtesy of php.net, the strings that describe the error indicated in $_FILES[{form field}]['error'].
    $upload_error_strings = array( false,
        __( "The uploaded file exceeds the <code>upload_max_filesize</code> directive in <code>php.ini</code>." ),
        __( "The uploaded file exceeds the <em>MAX_FILE_SIZE</em> directive that was specified in the HTML form." ),
        __( "The uploaded file was only partially uploaded." ),
        __( "No file was uploaded." ),
        __( "Missing a temporary folder." ),
        __( "Failed to write file to disk." ));

    // All tests are on by default. Most can be turned off by $override[{test_name}] = false;
    $test_form = true;
    $test_size = true;

    // If you override this, you must provide $ext and $type!!!!
    $test_type = true;

    // Install user overrides. Did we mention that this voids your warranty?
    if ( is_array( $overrides ) )
        extract( $overrides, EXTR_OVERWRITE );

    // A correct form post will pass this test.
    if ( $test_form && (!isset( $_POST['action'] ) || ($_POST['action'] != $action ) ) )
        return $upload_error_handler( $file, __( 'Invalid form submission.' ));

    // A successful upload will pass this test. It makes no sense to override this one.
    if ( $file['error'] > 0 )
        return $upload_error_handler( $file, $upload_error_strings[$file['error']] );

    // A non-empty file will pass this test.
    if ( $test_size && !($file['size'] > 0 ) )
        return $upload_error_handler( $file, __( 'File is empty. Please upload something more substantial.' ));

    // A properly uploaded file will pass this test. There should be no reason to override this one.
    if (! @ is_uploaded_file( $file['tmp_name'] ) )
        return $upload_error_handler( $file, __( 'Specified file failed upload test.' ));

    // A correct MIME type will pass this test. Override $mimes or use the upload_mimes filter.
    if ( $test_type ) {
        $wp_filetype = wp_check_filetype( $file['name'], $mimes );

        extract( $wp_filetype );

        if ( ( !$type || !$ext ) && !current_user_can( 'unfiltered_upload' ) )
            return $upload_error_handler( $file, __( 'File type does not meet security guidelines. Try another.' ));

        if ( !$ext )
            $ext = ltrim(strrchr($file['name'], '.'), '.');
    }

    // A writable uploads dir will pass this test. Again, there's no point overriding this one.
    if ( ! ( ( $uploads = wp_upload_dir() ) && false === $uploads['error'] ) )
        return $upload_error_handler( $file, $uploads['error'] );

    // Increment the file number until we have a unique file to save in $dir. Use $override['unique_filename_callback'] if supplied.
    if ( isset( $unique_filename_callback ) && function_exists( $unique_filename_callback ) ) {
        $filename = $unique_filename_callback( $uploads['path'], $file['name'] );
    } else {
        $number = '';
        $filename = str_replace( '#', '_', $file['name'] );
        $filename = str_replace( array( '\\', "'" ), '', $filename );
        if ( empty( $ext) )
            $ext = '';
        else
            $ext = ".$ext";
        while ( file_exists( $uploads['path'] . "/$filename" ) ) {
            if ( '' == "$number$ext" )
                $filename = $filename . ++$number . $ext;
            else
                $filename = str_replace( "$number$ext", ++$number . $ext, $filename );
        }
        $filename = str_replace( $ext, '', $filename );
        $filename = sanitize_title_with_dashes( $filename ) . $ext;
    }

    // Move the file to the uploads dir
    $new_file = $uploads['path'] . "/$filename";
    if ( false === @ move_uploaded_file( $file['tmp_name'], $new_file ) )
        wp_die( __('There was a problem uploading your file. Please try again.' ) );

    // Set correct file permissions
    $stat = stat( dirname( $new_file ));
    $perms = $stat['mode'] & 0000666;
    @ chmod( $new_file, $perms );

    // Compute the URL
    $url = $uploads['url'] . "/$filename";

    $return = apply_filters( 'wp_handle_upload', array( 'file' => $new_file, 'url' => $url, 'type' => $type ) );

    return $return;
}

?>