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1# Copyright 1999-2004 Gentoo Foundation 1# Copyright 1999-2004 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 1.11 2005/07/06 20:23:20 agriffis Exp $ 3# $Header: /var/cvsroot/gentoo-x86/eclass/alternatives.eclass,v 1.12 2005/07/11 15:08:06 swegener Exp $
4 4
5# Author : Alastair Tse <liquidx@gentoo.org> (03 Oct 2003) 5# Author : Alastair Tse <liquidx@gentoo.org> (03 Oct 2003)
6# Short Desc: Creates symlink to the latest version of multiple slotted 6# Short Desc: Creates symlink to the latest version of multiple slotted
7# packages. 7# packages.
8# 8#
10# 10#
11# When a package is SLOT'ed, very often we need to have a symlink to the 11# When a package is SLOT'ed, very often we need to have a symlink to the
12# latest version. However, depending on the order the user has merged them, 12# latest version. However, depending on the order the user has merged them,
13# more often than not, the symlink maybe clobbered by the older versions. 13# more often than not, the symlink maybe clobbered by the older versions.
14# 14#
15# This eclass provides a convenience function that needs to be given a 15# This eclass provides a convenience function that needs to be given a
16# list of alternatives (descending order of recent-ness) and the symlink. 16# list of alternatives (descending order of recent-ness) and the symlink.
17# It will choose the latest version if can find installed and create 17# It will choose the latest version if can find installed and create
18# the desired symlink. 18# the desired symlink.
19# 19#
20# There are two ways to use this eclass. First is by declaring two variables 20# There are two ways to use this eclass. First is by declaring two variables
21# $SOURCE and $ALTERNATIVES where $SOURCE is the symlink to be created and 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 22# $ALTERNATIVES is a list of alternatives. Second way is the use the function
23# alternatives_makesym() like the example below. 23# alternatives_makesym() like the example below.
24# 24#
25# Example: 25# Example:
26# 26#
27# pkg_postinst() { 27# pkg_postinst() {
28# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2" 28# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
29# } 29# }
30# 30#
31# The above example will create a symlink at /usr/bin/python to either 31# The above example will create a symlink at /usr/bin/python to either
35# Alternatively, you can use this function: 35# Alternatively, you can use this function:
36# 36#
37# pkg_postinst() { 37# pkg_postinst() {
38# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]" 38# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
39# } 39# }
40# 40#
41# This will use bash pathname expansion to fill a list of alternatives it can 41# 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 42# link to. It is probably more robust against version upgrades. You should
43# consider using this unless you are want to do something special. 43# consider using this unless you are want to do something special.
44# 44#
45 45
46# automatic deduction based on a symlink and a regex mask 46# automatic deduction based on a symlink and a regex mask
47alternatives_auto_makesym() { 47alternatives_auto_makesym() {
48 local SYMLINK REGEX ALT myregex 48 local SYMLINK REGEX ALT myregex
49 SYMLINK=$1 49 SYMLINK=$1
50 REGEX=$2 50 REGEX=$2
51 if [ "${REGEX:0:1}" != "/" ] 51 if [ "${REGEX:0:1}" != "/" ]
52 then 52 then
53 #not an absolute path: 53 #not an absolute path:
54 #inherit the root directory of our main link path for our regex search 54 #inherit the root directory of our main link path for our regex search
55 myregex="${SYMLINK%/*}/${REGEX}" 55 myregex="${SYMLINK%/*}/${REGEX}"
56 else 56 else
66 66
67alternatives_makesym() { 67alternatives_makesym() {
68 local ALTERNATIVES="" 68 local ALTERNATIVES=""
69 local SYMLINK="" 69 local SYMLINK=""
70 local alt pref 70 local alt pref
71 71
72 # usage: alternatives_makesym <resulting symlink> [alternative targets..] 72 # usage: alternatives_makesym <resulting symlink> [alternative targets..]
73 SYMLINK=$1 73 SYMLINK=$1
74 # this trick removes the trailing / from ${ROOT} 74 # this trick removes the trailing / from ${ROOT}
75 pref=$(echo ${ROOT} | sed 's:/$::') 75 pref=$(echo ${ROOT} | sed 's:/$::')
76 shift 76 shift
77 ALTERNATIVES=$@ 77 ALTERNATIVES=$@
78 78
79 # step through given alternatives from first to last 79 # step through given alternatives from first to last
80 # and if one exists, link it and finish. 80 # and if one exists, link it and finish.
81 81
82 for alt in ${ALTERNATIVES}; do 82 for alt in ${ALTERNATIVES}; do
83 if [ -f "${pref}${alt}" ]; then 83 if [ -f "${pref}${alt}" ]; then
84 #are files in same directory? 84 #are files in same directory?
85 if [ "${alt%/*}" = "${SYMLINK%/*}" ] 85 if [ "${alt%/*}" = "${SYMLINK%/*}" ]
86 then 86 then
93 ln -sf ${pref}${alt} ${pref}${SYMLINK} 93 ln -sf ${pref}${alt} ${pref}${SYMLINK}
94 fi 94 fi
95 break 95 break
96 fi 96 fi
97 done 97 done
98 98
99 # report any errors 99 # report any errors
100 if [ ! -L ${pref}${SYMLINK} ]; then 100 if [ ! -L ${pref}${SYMLINK} ]; then
101 ewarn "Unable to establish ${pref}${SYMLINK} symlink" 101 ewarn "Unable to establish ${pref}${SYMLINK} symlink"
102 else 102 else
103 # we need to check for either the target being in relative path form 103 # we need to check for either the target being in relative path form
104 # or absolute path form 104 # or absolute path form
105 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \ 105 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \
106 ! -f "`readlink ${pref}${SYMLINK}`" ]; then 106 ! -f "`readlink ${pref}${SYMLINK}`" ]; then
107 ewarn "${pref}${SYMLINK} is a dead symlink." 107 ewarn "${pref}${SYMLINK} is a dead symlink."
108 fi 108 fi
109 fi 109 fi
110} 110}
111 111
112alternatives_pkg_postinst() { 112alternatives_pkg_postinst() {
113 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 113 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
114 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 114 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
115 fi 115 fi
116} 116}
117 117
118alternatives_pkg_postrm() { 118alternatives_pkg_postrm() {
119 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 119 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
120 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 120 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
121 fi 121 fi
122} 122}
123 123
124EXPORT_FUNCTIONS pkg_postinst pkg_postrm 124EXPORT_FUNCTIONS pkg_postinst pkg_postrm
125

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