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1# Copyright 1999-2004 Gentoo Foundation 1# Copyright 1999-2011 Gentoo Foundation
2# Distributed under the terms of the GNU General Public License v2 2# Distributed under the terms of the GNU General Public License v2
3# $Header: /var/cvsroot/gentoo-x86/eclass/alternatives.eclass,v 1.1.1.1 2005/11/30 09:59:13 chriswhite Exp $ 3# $Header: /var/cvsroot/gentoo-x86/eclass/alternatives.eclass,v 1.17 2011/08/22 04:46:31 vapier Exp $
4 4
5# @ECLASS: alternatives.eclass
6# @AUTHOR:
5# Author : Alastair Tse <liquidx@gentoo.org> (03 Oct 2003) 7# Original author: Alastair Tse <liquidx@gentoo.org> (03 Oct 2003)
6# Short Desc: Creates symlink to the latest version of multiple slotted 8# @BLURB: Creates symlink to the latest version of multiple slotted packages.
7# packages. 9# @DESCRIPTION:
10# When a package is SLOT'ed, very often we need to have a symlink to the
11# latest version. However, depending on the order the user has merged them,
12# more often than not, the symlink maybe clobbered by the older versions.
8# 13#
9# Long Desc: 14# This eclass provides a convenience function that needs to be given a
15# list of alternatives (descending order of recent-ness) and the symlink.
16# It will choose the latest version it can find installed and create
17# the desired symlink.
10# 18#
11# When a package is SLOT'ed, very often we need to have a symlink to the 19# There are two ways to use this eclass. First is by declaring two variables
12# latest version. However, depending on the order the user has merged them, 20# $SOURCE and $ALTERNATIVES where $SOURCE is the symlink to be created and
13# more often than not, the symlink maybe clobbered by the older versions. 21# $ALTERNATIVES is a list of alternatives. Second way is the use the function
22# alternatives_makesym() like the example below.
23# @EXAMPLE:
24# pkg_postinst() {
25# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
26# }
14# 27#
15# This eclass provides a convenience function that needs to be given a 28# The above example will create a symlink at /usr/bin/python to either
16# list of alternatives (descending order of recent-ness) and the symlink. 29# /usr/bin/python2.3 or /usr/bin/python2.2. It will choose python2.3 over
17# It will choose the latest version if can find installed and create 30# python2.2 if both exist.
18# the desired symlink.
19# 31#
20# There are two ways to use this eclass. First is by declaring two variables 32# Alternatively, you can use this function:
21# $SOURCE and $ALTERNATIVES where $SOURCE is the symlink to be created and
22# $ALTERNATIVES is a list of alternatives. Second way is the use the function
23# alternatives_makesym() like the example below.
24# 33#
25# Example: 34# pkg_postinst() {
35# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
36# }
26# 37#
27# pkg_postinst() {
28# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
29# }
30#
31# The above example will create a symlink at /usr/bin/python to either
32# /usr/bin/python2.3 or /usr/bin/python2.2. It will choose python2.3 over
33# python2.2 if both exist.
34#
35# Alternatively, you can use this function:
36#
37# pkg_postinst() {
38# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
39# }
40#
41# This will use bash pathname expansion to fill a list of alternatives it can 38# This will use bash pathname expansion to fill a list of alternatives it can
42# link to. It is probably more robust against version upgrades. You should 39# link to. It is probably more robust against version upgrades. You should
43# consider using this unless you are want to do something special. 40# consider using this unless you are want to do something special.
44#
45 41
42# @ECLASS-VARIABLE: SOURCE
43# @DEFAULT_UNSET
44# @DESCRIPTION:
45# The symlink to be created
46
47# @ECLASS-VARIABLE: ALTERNATIVES
48# @DEFAULT_UNSET
49# @DESCRIPTION:
50# The list of alternatives
51
52# @FUNCTION: alternatives_auto_makesym
53# @DESCRIPTION:
46# automatic deduction based on a symlink and a regex mask 54# automatic deduction based on a symlink and a regex mask
47alternatives_auto_makesym() { 55alternatives_auto_makesym() {
48 local SYMLINK REGEX ALT myregex 56 local SYMLINK REGEX ALT myregex
49 SYMLINK=$1 57 SYMLINK=$1
50 REGEX=$2 58 REGEX=$2
102 else 110 else
103 # we need to check for either the target being in relative path form 111 # we need to check for either the target being in relative path form
104 # or absolute path form 112 # or absolute path form
105 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \ 113 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \
106 ! -f "`readlink ${pref}${SYMLINK}`" ]; then 114 ! -f "`readlink ${pref}${SYMLINK}`" ]; then
107 ewarn "${pref}${SYMLINK} is a dead symlink." 115 ewarn "Removing dead symlink ${pref}${SYMLINK}"
116 rm -f ${pref}${SYMLINK}
108 fi 117 fi
109 fi 118 fi
110} 119}
111 120
121# @FUNCTION: alernatives-pkg_postinst
122# @DESCRIPTION:
123# The alternatives pkg_postinst, this function will be exported
112alternatives_pkg_postinst() { 124alternatives_pkg_postinst() {
113 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 125 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
114 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 126 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
115 fi 127 fi
116} 128}
117 129
130# @FUNCTION: alternatives_pkg_postrm
131# @DESCRIPTION:
132# The alternatives pkg_postrm, this function will be exported
118alternatives_pkg_postrm() { 133alternatives_pkg_postrm() {
119 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 134 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
120 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 135 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
121 fi 136 fi
122} 137}

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