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1# Copyright 1999-2003 Gentoo Technologies, Inc. 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 1.4 2003/11/01 17:35:59 liquidx 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# $ALTERNATIVES is a list of alternatives. Second way is the use the function
23# alternatives_makesym() like the example below.
24# 33#
25# Example:
26#
27# pkg_postinst() { 34# pkg_postinst() {
28# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2" 35# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
29# } 36# }
30# 37#
31# The above example will create a symlink at /usr/bin/python to either
32# /usr/bin/python2.3 or /usr/bin/python2.2. It will choose python2.3 over
33# python2.2 if both exist.
34#
35# Alternatively, you can use this function:
36#
37# pkg_postinst() {
38# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
39# }
40#
41# This will use bash pathname expansion to fill a list of alternatives it can 38# This will use bash pathname expansion to fill a list of alternatives it can
42# link to. It is probably more robust against version upgrades. You should 39# link to. It is probably more robust against version upgrades. You should
43# consider using this unless you are want to do something special. 40# consider using this unless you are want to do something special.
44#
45ECLASS="alternatives"
46INHERITED="$INHERITED $ECLASS"
47 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:
48# automatic deduction based on a symlink and a regex mask 54# automatic deduction based on a symlink and a regex mask
49alternatives_auto_makesym() { 55alternatives_auto_makesym() {
50 local SYMLINK REGEX ALT myregex 56 local SYMLINK REGEX ALT myregex
51 SYMLINK=$1 57 SYMLINK=$1
52 REGEX=$2 58 REGEX=$2
53 if [ "${REGEX:0:1}" != "/" ] 59 if [ "${REGEX:0:1}" != "/" ]
54 then 60 then
55 #not an absolute path: 61 #not an absolute path:
56 #inherit the root directory of our main link path for our regex search 62 #inherit the root directory of our main link path for our regex search
57 myregex="${SYMLINK%/*}/${REGEX}" 63 myregex="${SYMLINK%/*}/${REGEX}"
58 else 64 else
59 myregex=${REGEX} 65 myregex=${REGEX}
60 fi 66 fi
61 ALT="`echo ${myregex} | sort -r`" 67
68 # sort a space delimited string by converting it to a multiline list
69 # and then run sort -r over it.
70 # make sure we use ${ROOT} because otherwise stage-building will break
71 ALT="$(for i in $(echo ${ROOT}${myregex}); do echo ${i#${ROOT}}; done | sort -r)"
62 alternatives_makesym ${SYMLINK} ${ALT} 72 alternatives_makesym ${SYMLINK} ${ALT}
63} 73}
64 74
65alternatives_makesym() { 75alternatives_makesym() {
66 local ALTERNATIVES="" 76 local ALTERNATIVES=""
67 local SYMLINK="" 77 local SYMLINK=""
68 local alt pref 78 local alt pref
79
69 # usage: alternatives_makesym <resulting symlink> [alternative targets..] 80 # usage: alternatives_makesym <resulting symlink> [alternative targets..]
70 SYMLINK=$1 81 SYMLINK=$1
71 pref=${ROOT:0:${#ROOT}-1} 82 # this trick removes the trailing / from ${ROOT}
83 pref=$(echo ${ROOT} | sed 's:/$::')
72 shift 84 shift
73 ALTERNATIVES=$@ 85 ALTERNATIVES=$@
74 86
75 # step through given alternatives from first to last 87 # step through given alternatives from first to last
76 # and if one exists, link it and finish. 88 # and if one exists, link it and finish.
77 89
78 for alt in ${ALTERNATIVES}; do 90 for alt in ${ALTERNATIVES}; do
79 if [ -f "${pref}${alt}" ]; then 91 if [ -f "${pref}${alt}" ]; then
80 einfo "Linking ${alt} to ${pref}${SYMLINK}"
81 [ -L "${pref}${SYMLINK}" ] && rm -f ${pref}${SYMLINK}
82 #are files in same directory? 92 #are files in same directory?
83 if [ "${alt%/*}" = "${SYMLINK%/*}" ] 93 if [ "${alt%/*}" = "${SYMLINK%/*}" ]
84 then 94 then
85 #yes; strip leading dirname from alt to create relative symlink 95 #yes; strip leading dirname from alt to create relative symlink
96 einfo "Linking ${alt} to ${pref}${SYMLINK} (relative)"
86 ln -s ${alt##*/} ${pref}${SYMLINK} 97 ln -sf ${alt##*/} ${pref}${SYMLINK}
87 else 98 else
88 #no; keep absolute path 99 #no; keep absolute path
100 einfo "Linking ${alt} to ${pref}${SYMLINK} (absolute)"
89 ln -s ${pref}${alt} ${pref}${SYMLINK} 101 ln -sf ${pref}${alt} ${pref}${SYMLINK}
90 fi 102 fi
91 break 103 break
92 fi 104 fi
93 done 105 done
94 106
95 # report any errors 107 # report any errors
96 if [ ! -L ${pref}${SYMLINK} ]; then 108 if [ ! -L ${pref}${SYMLINK} ]; then
97 ewarn "Unable to establish ${pref}${SYMLINK} symlink" 109 ewarn "Unable to establish ${pref}${SYMLINK} symlink"
98 else 110 else
99 # 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
100 # or absolute path form 112 # or absolute path form
101 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \ 113 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \
102 ! -f "`readlink ${pref}${SYMLINK}`" ]; then 114 ! -f "`readlink ${pref}${SYMLINK}`" ]; then
103 ewarn "${pref}${SYMLINK} is a dead symlink." 115 ewarn "Removing dead symlink ${pref}${SYMLINK}"
116 rm -f ${pref}${SYMLINK}
104 fi 117 fi
105 fi 118 fi
106} 119}
107 120
121# @FUNCTION: alernatives-pkg_postinst
122# @DESCRIPTION:
123# The alternatives pkg_postinst, this function will be exported
108alternatives_pkg_postinst() { 124alternatives_pkg_postinst() {
109 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 125 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
110 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 126 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
111 fi 127 fi
112} 128}
113 129
130# @FUNCTION: alternatives_pkg_postrm
131# @DESCRIPTION:
132# The alternatives pkg_postrm, this function will be exported
114alternatives_pkg_postrm() { 133alternatives_pkg_postrm() {
115 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 134 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
116 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 135 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
117 fi 136 fi
118} 137}
119 138
120EXPORT_FUNCTIONS pkg_postinst pkg_postrm 139EXPORT_FUNCTIONS pkg_postinst pkg_postrm
121

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