Decoding¶

File list data read from the remote rsync should be passed to the decode() function. The data may be read and processed in arbitrary sized chunks. The decode() function returns how many bytes were actually processed. It is the caller's responsbility to remove that number of bytes from the input argument, preserving the remaining bytes for the next call to decode(). The decodeDone() function returns true when the file list is complete. The fatalError() function returns true if there was a non-recoverable error while decoding.

The clean() function needs to be called after the file list decode is complete. The clean() function sorts the file list and removes repeated entries. Skipping this step will produce unexpected results: since files are referred to using integers, each side will refer to different files is the file lists are not sorted and purged in exactly the same manner.

A typical decode loop looks like:

    while ( !$fileList->decodeDone && !$fileList->fatalError ) {
        $data .= readMoreDataFromRemoteRsync();
        $bytesDone = $fileList->decode($data);
        $data = substr($data, $bytesDone) if ( $bytesDone > 0 );
    }
    $fileList->clean;

After clean() is called, the number of files in the file list can be found by calling count(). Files can be fetched by calling the get() function, with an index from 0 to count()-1:

    $fileInfo = $fileList->get(5);

The get() function returns a hashref with various entries:

        name      path name of the file (relative to rsync dir):
                  equal to dirname/basename
        basename  file name, without directory
        dirname   directory where file resides
        sum       file MD4 checksum (only present if --checksum specified)
        uid       file user id
        gid       file group id
        mode      file mode
        mtime     file modification time
        size      file length
        dev       device number on which file resides
        inode     file inode
        link      link contents if the file is a sym link
        rdev      major/minor device number if file is char/block special

Various fields will only have valid values if the corresponding options are set (eg: uid if preserve_uid is set, dev and inode if preserve_hard_links is set etc).

For example, to dump out each of hash you could do this:

    use Data::Dumper;
    my $count = $fileList->count;
    for ( my $i = 0 ; $i < $count ; $i++ ) {
        print("File $i is:\n");
        print Dumper($fileList->get($i));
    }

Encoding¶

In this example the matching stat() values are shown:

    $fileList->encode({
            name  => $filePath,
            dev   => $stat[0],
            inode => $stat[1],
            mode  => $stat[2],
            uid   => $stat[4],
            gid   => $stat[5],
            rdev  => $stat[6],
            size  => $stat[7],
            mtime => $stat[9],
        });

It is not necessary to specify basename and dirname; these are extracted from name. You only need to specify the parameters that match the options given to new(). You can also specify sum and link as necessary.

To compute the encoded file list data the encodeData() function should be called. It can be called every time encode() is called, or once at the end of all the encode() calls. It returns the encoded data that should be sent to the remote rsync:

    $data = $fileList->encodeData;

It is recommended that encodeData() be called frequently to avoid the need to allocate large internal buffers to hold the entire encoded file list. Since encodeData() does not know when the last file has been encoded, it is the caller's responsbility to add the final null byte (eg: pack("C", 0)) to the data to indicate the end of the file list data.

After all the file list entries are processed you should call clean():

    $fileList->clean;

This ensures that each side (sender/receiver) has identical sorted file lists.

Utility functions¶

The fatalError() function returns true if a fatal error has occured during file decoding. It should be called in the decode loop to make sure no error has occured.