Alien::Package(3)

NAME
Alien::Package - an object that represents a package

DESCRIPTION
This is a perl object class that represents a package in an internal format usable by alien. The package may be a deb, a rpm, a tgz, or a slp package, etc. Objects in this class hold various fields of metadata from the actual packages they represent, as well as some fields pointing to the actual contents of the package. They can also examine an actual package on disk, and populate those fields. And they can build the actual package using the data stored in the fields.

A typical use of this object class will be to instantiate an object from a class derived from this one, such as Alien::Package::Rpm. Feed the object a rpm file, thus populating all of its fields. Then rebless the object into the destination class, such as Alien::Package::Deb. Finally, ask the object to build a package, and the package has been converted.

FIELDS
These fields are of course really just methods that all act similarly; allowing a value to be passed in to set them, or simply returning the value of the field if nothing is passed in. Child classes may override these fields to process input data, or to format output data. The general rule is that input data is modified to get things into a package-independant form, which is how the data is stored in the fields. When the value of a field is read, it too may be modified before it is returned, to change things into a form more suitable for the particular type of package.

name
    The package's name.

version
    The package's upstream version.

release
    The package's distribution specific release number.

arch
    The package's architecture, in the format used by Debian.

maintainer
    The package's maintainer.

depends
    The package's dependencies. Only dependencies that should exist on all target distributions can be put in here though (ie: lsb).

group
    The section the package is in.

summary
    A one line description of the package.

description
    A longer description of the package. May contain multiple paragraphs.

copyright
    A short statement of copyright.

origformat
    What format the package was originally in.

distribution
    What distribution family the package originated from.

binary_info
    Whatever the package's package tool says when told to display info about the package.

conffiles
    A reference to a list of all the conffiles in the package.

files
    A reference to a list of all the files in the package.

changelogtext
    The text of the changelog

postinst
    The postinst script of the package.

postrm
    The postrm script of the package.

preinst
    The preinst script of the package.

prerm
    The prerm script of the package.

usescripts
    Only use the above scripts fields when generating the package if this is set to a true value.

unpacked_tree
    Points to a directory where the package has been unpacked.

owninfo
    If set this will be a reference to a hash, with filename as key, that holds ownership/group information for files that cannot be represented on the filesystem. Typically that is because the owners or groups just don't exist yet. It will be set at unpack time.

modeinfo
    If set this will be a reference to a hash, with filename as key, that holds mode information for setuid files that have an entry in owninfo. It will be set at unpack time.

METHODS

init
    This is called by new(). It's a handy place to set fields, etc, without having to write your own new() method.

install
    Simply installs a package file. The filename is passed. This has to be overridden in child classes.

test
    Test a package file. The filename is passed, should return an array of lines of test results. Child classses may implement this.

filename
    Set/get the filename of the package the object represents.

    When it is set, it performs a scan of the file, populating most other fields with data from it.

    (This is just a stub; child classes should override it to actually do something.)

scripts
    Returns a list of all non-empty maintainer scripts in the package.

scan
    This method scans the file associated with an object, and populates as many other fields as it can with data from it.

unpack
    This method unpacks the package into a temporary directory. It sets unpacked_tree to point to that directory.

    (This is just a stub method that makes a directory below the current working directory, and sets unpacked_tree to point to it. It should be overridden by child classes to actually unpack the package as well.)

prep
    This method causes the object to prepare a build tree to be used in building the object. It expects that the unpack method has already been called. It takes the tree generated by that method, and mangles it somehow, to produce a suitable build tree.

    (This is just a stub method that all child classes should override.)

cleantree
    This method should clean the unpacked_tree of any effects the prep and build methods might have on it.

revert
    This method should ensure that the object is in the same state it was in before the prep method was called.

build
    This method takes a prepped build tree, and simply builds a package from it. It should put the package in the current directory, and should return the filename of the generated package.

    (This is just a stub method that all child classes should override.)

incrementrelease
    This method should increment the release field of the package by the specified number.

DESTROY
    When an object is destroyed, it cleans some stuff up. In particular, if the package was unpacked, it is time now to wipe out the temporary directory.

AUTOLOAD
    Handles all fields, by creating accessor methods for them the first time they are accessed.

CLASS DATA

$Alien::Package::verbose
    If set to a nonzero value, the shell commands that are run should be output. If set to a value greater than 1, any output of the commands should also be output.

CLASS METHODS
These methods can be called on either an object or on the class itself.

new Returns a new object of this class. Optionally, you can pass in named parameters that specify the values of any fields in the class.

checkfile
    Pass it a filename, and it will return true if it looks like the file is a package of the type handled by the class.

do  Runs a shell command. Is verbose or not depending on the value of $Alien::Package::verbose. Returns true if the command succeeds, false on failure.

runpipe
    This is similar to backticks, but honors $Alien::Package::verbose, logging the command run if asked to. The output of the command is returned.

    The first parameter controls what to do on error. If it's true then any errors from the command will be ignored (and $? will be set). If it's false, errors will abort alien.

AUTHOR
Joey Hess <joey@kitenet.net>