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Alien::Package

Section: User Contributed Perl Documentation (3)
Updated: 2003-10-14
Index

NAME

Alien::Package - an object that represents a package

DESCRIPTION

This is a perl object class that represents a package in an internal formatusable 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 actualpackages they represent, as well as some fields pointing to the actualcontents of the package. They can also examine an actual package on disk,and populate those fields. And they can build the actual package using thedata stored in the fields.

A typical use of this object class will be to instantiate an object froma class derived from this one, such as Alien::Package::Rpm. Feed the objecta rpm file, thus populating all of its fields. Then rebless the object intothe destination class, such as Alien::Package::Deb. Finally, ask the objectto 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 valueof the field if nothing is passed in. Child classes may override thesefields to process input data, or to format output data. The general rule isthat 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 isread, it too may be modified before it is returned, to change things into aform 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 dependancies. Only dependencies that should exist on alltarget 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 aboutthe 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 setto 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 holdsownership/group information for files that cannot be represented on thefilesystem. Typically that is because the owners or groups just don't existyet. It will be set at unpack time.
modeinfo: If set this will be a reference to a hash, with filename as key, thatholds 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, withouthaving 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 linesof 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 otherfields with data from it.

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

scan

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

unpack

This method unpacks the package into a temporary directory. It setsunpacked_tree to point to that directory.

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

prep

This method causes the object to prepare a build tree to be used inbuilding the object. It expects that the unpack method has already beencalled. 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 andbuild methods might have on it.

revert

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

build

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

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

DESTROY

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

AUTOLOAD

Handles all fields, by creating accessor methods for them the first timethey 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 beoutput.

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 namedparameters 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 isa 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, loggingthe command run if asked to. The output of the command returned.

AUTHOR

Joey Hess <joeyAATTkitenet.net>

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