#!/bin/sh
# $Id: git-pbuilder,v 1.16 2010-09-01 21:30:33 eagle Exp $
#
# git-pbuilder -- Wrapper around pbuilder for git-buildpackage
#
# Written by Russ Allbery <rra@stanford.edu>
# Based on the example in the git-buildpackage documentation
# Copyright 2008, 2009, 2010 Board of Trustees, Leland Stanford Jr. University
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose and without fee is hereby granted, provided
# that the above copyright notice appear in all copies and that both that
# copyright notice and this permission notice appear in supporting
# documentation, and that the name of Stanford University not be used in
# advertising or publicity pertaining to distribution of the software without
# specific, written prior permission.  Stanford University makes no
# representations about the suitability of this software for any purpose.  It
# is provided "as is" without express or implied warranty.
#
# THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

set -e

# The root directory where different cowbuilder --basepath directories are
# found.  git-pbuilder expects them to be named base-<dist>.cow.
COWBUILDER_BASE=/var/cache/pbuilder

# Make sure we have the necessary tools
if [ ! -x /usr/sbin/cowbuilder ]; then
    echo "Cowbuilder not found; you need to install the cowbuilder package" >&2
    exit 1
fi

# Set DIST based on the name we were invoked as.  This allows people to create
# symlinks like git-pbuilder-lenny pointing to git-pbuilder and auto-detecting
# the distribution from that.
if [ -z "$DIST" ] ; then
    DIST=${0#*git-pbuilder-}
    case $DIST in
    *git-pbuilder*) DIST= ;;
    esac
fi
if [ -n "$DIST" ] ; then
    if [ -n "$ARCH" ] ; then
        echo "Building for distribution $DIST, architecture $ARCH"
    else
        echo "Building for distribution $DIST"
    fi
fi

# If DIST is set, use base-$DIST.cow.  If DIST is not set, the sid chroot may
# be either base.cow or base-sid.cow.  Try both.  If ARCH is set, use
# base-$DIST-$ARCH.cow.
OPTIONS=
if [ -z "$DIST" ] ; then
    DIST=sid
fi
if [ -n "$ARCH" ] ; then
    BASE="$COWBUILDER_BASE/base-$DIST-$ARCH.cow"
    OPTIONS="--architecture $ARCH"
elif [ "$DIST" = 'sid' ] ; then
    if [ -d "$COWBUILDER_BASE/base-sid.cow" ] ; then
        BASE="$COWBUILDER_BASE/base-sid.cow"
    else
        BASE="$COWBUILDER_BASE/base.cow"
    fi
else
    BASE="$COWBUILDER_BASE/base-$DIST.cow"
fi

# Make sure the base directory exists.
if [ ! -d "$BASE" ] && [ "$1" != "create" ]; then
    echo "Base directory $BASE does not exist" >&2
    exit 1
fi

# Set --debian-etch-workaround if DIST is etch.  Assume that everything else
# is new enough that it will be fine.
if [ "$DIST" = 'etch' ] || [ "$DIST" = 'ebo' ] ; then
    OPTIONS="$OPTIONS --debian-etch-workaround"
fi

# If the first argument to the script is update, create, or login, run
# cowbuilder with the corresponding option under sudo rather than proceeding.
case $1 in
update|create|login)
    action="$1"
    shift
    sudo cowbuilder --"$action" --basepath "$BASE" --dist "$DIST" $OPTIONS "$@"
    exit $?
    ;;
*)
    if [ -z "$GBP_BUILD_DIR" ]; then
        echo "WARNING: not invoked by git-buildpackage." >&2
    fi
    ;;
esac

# Now we can finally run pdebuild.  The quoting here is tricky, but this
# seems to pass everything through properly.
pdebuild --buildresult .. --pbuilder cowbuilder \
    --debbuildopts "-i'(?:^|/)\\.git(attributes)?(?:\$|/.*\$)' -I.git $*" \
    -- --basepath "$BASE" $OPTIONS
if [ -n "`ls ../*_source.changes`" ] ; then
    rm ../*_source.changes
fi
exit 0

# Documentation.  Use a hack to hide this from the shell.  Because of the
# above exit line, this should never be executed.
DOCS=<<__END_OF_DOCS__

=head1 NAME

git-pbuilder - Wrapper around pbuilder for git-buildpackage

=head1 SYNOPSIS

DIST=I<distribution> ARCH=I<architecture> B<git-pbuilder> I<debbuild-options>

DIST=I<distribution> ARCH=I<architecture> \
    B<git-pbuilder> (update | create | login) I<cowbuilder-options>

=head1 DESCRIPTION

B<git-pbuilder> is a wrapper around B<pdebuild> intended for use by
B<git-buildpackage>.  It configures B<pdebuild> to use B<cowbuilder>,
passes appropriate options to B<debbuild>, and sets the base path for
B<cowbuilder> based on the environment variable DIST and, if set, the
environment variable ARCH.

By default, B<git-pbuilder> assumes the target distribution is C<sid>, the
same architecture as the B<cowbuilder> default, and uses
F</var/cache/pbuilder/base-sid.cow> if it exists.  If it doesn't,
F</var/cache/pbuilder/base.cow> is tried.  If DIST is set, its value is
the target distribution and F</var/cache/pbuilder/base-I<dist>.cow> is
used instead.  If DIST is C<etch> or C<ebo>, B<--debian-etch-workaround>
is also passed to B<cowbuilder>.  If ARCH is set, its value is the target
architecture and F</var/cache/pbuilder/base-I<dist>-I<arch>.cow> is used,
with I<dist> being set to C<sid> if DIST was not set.

If B<git-pbuilder> is invoked via a name that starts with
C<git-pbuilder->, the part after the last hyphen is taken to be the
distribution (although the environment variable overrides this).  One can
therefore create symlinks like C<git-pbuilder-lenny> pointing to
B<git-pbuilder> and use that name when wanting to use a distribution of
C<lenny>.

Any arguments are passed as-is to B<dpkg-buildpackage> via the
B<--debbuildopts> option to B<pdebuild>.

Normally, one does not run this script directly.  Instead, it's used as
the builder script for B<git-buildpackage>.  To configure
B<git-buildpackage> to use it, add a stanza like:

    [DEFAULT]
    builder = /path/to/git-pbuilder

in your F<gbp.conf> file (which can be F<.gbp.conf> in your home directory
or at the top level of the repository, or F<gbp.conf> in the F<.git>
directory).  DIST is read as an environment variable so that you can set
it before running B<git-buildpackage> without having to worry about
passing parameters through B<git-buildpackage>.

Alternately, B<git-pbuilder> may be called with an argument of C<update>,
C<create>, or C<login>.  In this case, it calls B<cowbuilder> using
B<sudo> and passes the corresponding command to B<cowbuilder>, using the
same logic as above to determine the base directory and distribution.  Any
additional arguments to B<git-pbuilder> are passed along to B<cowbuilder>.

=head1 ENVIRONMENT

=over 4

=item DIST

Sets the target distribution.  This is used primarily to determine the
base path for B<cowbuilder>, but it's also used to determine whether to
pass B<--debian-etch-workaround> to B<cowbuilder>.

=back

=head1 FILES

=over 4

=item /var/cache/pbuilder/base-sid.cow

=item /var/cache/pbuilder/base.cow

The default C<cowbuilder --basepath> directories, searched for in that
order, if DIST is not set.

=item /var/cache/pbuilder/base-$DIST.cow

The C<cowbuilder --basepath> directory used if DIST is set.

=back

=head1 SEE ALSO

cowbuilder(8), dpkg-buildpackage(1), git-buildpackage(1), pdebuild(1),
sudo(8)

The latest version of this script is available from
L<http://www.eyrie.org/~eagle/software/scripts/>.

=head1 AUTHOR

Russ Allbery <rra@stanford.edu>

=cut

__END_OF_DOCS__