NAME
    File::RdistByRsync - read rdist distfiles, emulate using rsync

SYNOPSIS
            use File::RdistByRsync

            @dist_blocks = parse_rdist($distfile, %options)

            ($args, $extras, @dist_blocks) = rdist(@ARGV);

            rsync(@ARGV)

            perl -MFile::RdistByRsync -e 'rsync(qw/rdist command flags/)'

DESCRIPTION
    File::RdistByRsync parses and understands rdist distfiles and command
    lines.

    It can share it's understanding by returning what it got
    ("parse_rdist()" and "rdist()") or it can attempt to emulate rdist using
    rsync.

    Why?

    Well, because rdist is so slow it's unusable and rsync has such a
    limited interface that it's unusable. I'm sure a better specification
    language than rdist's could be developed, but rdist's language already
    exists so I used it to drive rsync.

WARNING
    As of this writing, this code is still green. Use the "-D" "-n" and "-v"
    options and look at the output. Look carefully. If it looks good, then
    try running it for real. If it deletes all your files, then you didn't
    look carefully enough. Don't blame me. See the LICENSE.

DATA STRUCTURE
    The main return value from rdist is an array of distribution blocks.

    They look like:

            {
                    HOSTS           => [ host1 user@host2 host3 etc...],
                    FILES           => [ /etc/rc.* /etc/hosts /usr etc...],
                    EXCEPT          => [
                            # tuples of type & file
                            EXCEPT_PAT      /etc/p.*d       # regular expression
                            EXCEPT          /etc/rc.local   # glob
                            RSYNC_EXCLUDE   /etc/rc.loc*    # glob-style pattern exclusions
                            RSYNC_INCLUDE   /etc/rc.*       # glob-style pattern inclusions
                    ]
                    SPECIAL         => [
                                {
                                    FILES   => /etc/login.conf      # glob okay
                                    COMMAND => "cap_mkdb $FILE"     # a command to run
                                },
                                {
                                    FILES   => /etc/named.conf      # glob okay
                                    COMMAND => "ndc reload"         # a command to run
                                },
                            ]
                    RSYNC_OPTION    => [ --dry-run --verbose ]
                    INSTALL         => [
                                {
                                    DESTINATION => /usr             # where to install
                                    FLAGS       => {
                                            R => 1,                 # remove extra
                                            w => 1,                 # append whole path
                                    }
                                }
                    TSFILE          => /some/file                   # touch file name
            }

DETAILS
            @dist_blocks = parse_rdist($distfile, %options)

    There is one "dist_block" for each "::" or "->" entry in the distfile.

    The options supported by parse_rdist are "DEFINES => {}" which override
    variable definitions made in the distfile and "TARGETS => []" which
    filters the results so that entries that don't match label targets (if
    any match) and files that don't match file targets are removed.

            ($args, $extras, @dist_blocks) = rdist(@ARGV);

    "$args" comes from the Getopt::Declare manpage. See the grammer inside
    File::RdistByRsync for full details, but basically "$args-"{"-y"}> is
    true if "@ARGV" contained "-y".

    "$extras" is a hash of a few items that are sometimes useful.
    "$extras-"{HOSTS}> is the list of hosts specified with the "-m" option.
    "$extras-"{DEFINES}> is a hash of "-d" variable definitions.
    "$extras-"{RSYNCOPT}> is a list of rsync options specified in "@ARGV".
    "$extra-"{TARGETS}> is a list of distfile entries (by label) or
    filenames given in "@ARGV" to limit the scope of the invocation.
    "$extra-"{CFLAG}> is a dist_block created if there is a command-line
    style distfile.

            rsync(@ARGV)

    The "rsync()" function does the whole job. The "@ARGV" parameter should
    be an rdist-style command line.

COMPATABILITY
    All rdist switches except "-i" are honored. The output is quite
    different from rdist. Multiple invocations of rsync can be required to
    do a single rdist.

    Two features of rdist are currently ignored: email notification and
    timestamp checking with "::" productions.

    There are some additional features that are useful when using "rsync()".

    First, the long-form of rsync command line arguments are noticed by
    "rdist()" and used by "rsync()".

    Second, in the "->" productions, three new commands are available:

            'rsync_options' <options> ';'
            'rsync_include' <name list> ';'
            'rsync_exclude' <name list> ';'

    Rsync_options will be passed to any rsync commands called by "rsync()"
    that operate on the block in question.

    Rsync_include and rsync_exclude will be passed to rsync with "- "
    prepended for the excludes and "+ " prepended for the includes. When
    building rsync exclusion lists, the order of the 'rsync_include',
    'rsync_exclude', 'except', and 'except_pat' are taken into account and
    preserved.

LICENSE
    Copyright (C) 2002 David Muir Sharnoff. License hereby granted for
    anyone to use, modify or redistribute this module at their own risk. Use
    of this module consitutes an agreement to indemnify and hold harmless
    the author(s) for whatever might happen when using this code. Please
    feed useful changes back to muir@idiom.com.

