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1# Copyright 1999-2003 Gentoo Technologies, Inc. 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 1.1 2003/10/07 17:21:40 liquidx Exp $ 3# $Header: /var/cvsroot/gentoo-x86/eclass/alternatives.eclass,v 1.1.1.1 2005/11/30 09:59:13 chriswhite 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# $ALTERNATIVES is a list of alternatives. Second way is the use the function
23# alternatives_makesym() like the example below. 23# alternatives_makesym() like the example below.
24# 24#
25# Example: 25# Example:
26# 26#
27# pkg_postinst() { 27# pkg_postinst() {
28# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2" 28# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
29# } 29# }
30# 30#
31# The above example will create a symlink at /usr/bin/python to either 31# The above example will create a symlink at /usr/bin/python to either
35# Alternatively, you can use this function: 35# Alternatively, you can use this function:
36# 36#
37# pkg_postinst() { 37# pkg_postinst() {
38# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]" 38# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
39# } 39# }
40# 40#
41# This will use bash pathname expansion to fill a list of alternatives it can 41# This will use bash pathname expansion to fill a list of alternatives it can
42# link to. It is probably more robust against version upgrades. You should 42# link to. It is probably more robust against version upgrades. You should
43# consider using this unless you are want to do something special. 43# consider using this unless you are want to do something special.
44# 44#
45ECLASS="alternatives"
46INHERITED="$INHERITED $ECLASS"
47 45
48# automatic deduction based on a symlink and a regex mask 46# automatic deduction based on a symlink and a regex mask
49alternatives_auto_makesym() { 47alternatives_auto_makesym() {
50 local SOURCE REGEX ALT 48 local SYMLINK REGEX ALT myregex
51 local unsorted 49 SYMLINK=$1
52 SOURCE=$1
53 REGEX=$2 50 REGEX=$2
51 if [ "${REGEX:0:1}" != "/" ]
52 then
53 #not an absolute path:
54 #inherit the root directory of our main link path for our regex search
55 myregex="${SYMLINK%/*}/${REGEX}"
56 else
57 myregex=${REGEX}
58 fi
54 59
55 ALT="`ls -1 ${ROOT}${REGEX} | sort -r | xargs`" 60 # sort a space delimited string by converting it to a multiline list
56 if [ -n "${ALT}" ]; then 61 # and then run sort -r over it.
62 # make sure we use ${ROOT} because otherwise stage-building will break
63 ALT="$(for i in $(echo ${ROOT}${myregex}); do echo ${i#${ROOT}}; done | sort -r)"
57 alternatives_makesym ${SOURCE} ${ALT} 64 alternatives_makesym ${SYMLINK} ${ALT}
58 else
59 eerror "regex ${REGEX} doesn't match any files."
60 fi
61} 65}
62 66
63alternatives_makesym() { 67alternatives_makesym() {
64 local ALTERNATIVES="" 68 local ALTERNATIVES=""
65 local SOURCE="" 69 local SYMLINK=""
66 70 local alt pref
71
67 # usage: alternatives_makesym <resulting symlink> [alternative targets..] 72 # usage: alternatives_makesym <resulting symlink> [alternative targets..]
68 SOURCE=$1 73 SYMLINK=$1
74 # this trick removes the trailing / from ${ROOT}
75 pref=$(echo ${ROOT} | sed 's:/$::')
69 shift 76 shift
70 ALTERNATIVES=$@ 77 ALTERNATIVES=$@
71 78
72 # step through given alternatives from first to last 79 # step through given alternatives from first to last
73 # and if one exists, link it and finish. 80 # and if one exists, link it and finish.
74 81
75 for alt in ${ALTERNATIVES}; do 82 for alt in ${ALTERNATIVES}; do
76 if [ -f "${ROOT}${alt}" ]; then 83 if [ -f "${pref}${alt}" ]; then
77 if [ -L "${ROOT}${SOURCE}" ]; then 84 #are files in same directory?
78 rm -f ${ROOT}${SOURCE} 85 if [ "${alt%/*}" = "${SYMLINK%/*}" ]
86 then
87 #yes; strip leading dirname from alt to create relative symlink
88 einfo "Linking ${alt} to ${pref}${SYMLINK} (relative)"
89 ln -sf ${alt##*/} ${pref}${SYMLINK}
90 else
91 #no; keep absolute path
92 einfo "Linking ${alt} to ${pref}${SYMLINK} (absolute)"
93 ln -sf ${pref}${alt} ${pref}${SYMLINK}
79 fi 94 fi
80 einfo "Linking ${alt} to ${SOURCE}"
81 ln -s ${alt} ${ROOT}${SOURCE}
82 break 95 break
83 fi 96 fi
84 done 97 done
85 98
86 # report any errors 99 # report any errors
87 if [ ! -L ${ROOT}${SOURCE} ]; then 100 if [ ! -L ${pref}${SYMLINK} ]; then
88 ewarn "Unable to establish ${SOURCE} symlink" 101 ewarn "Unable to establish ${pref}${SYMLINK} symlink"
89 elif [ ! -f "`readlink ${ROOT}${SOURCE}`" -a ! -f "${ROOT}`readlink ${ROOT}${SOURE}`" ]; then 102 else
103 # we need to check for either the target being in relative path form
104 # or absolute path form
105 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \
106 ! -f "`readlink ${pref}${SYMLINK}`" ]; then
90 ewarn "${SOURCE} is a dead symlink." 107 ewarn "${pref}${SYMLINK} is a dead symlink."
108 fi
91 fi 109 fi
92} 110}
93 111
94alternatives_pkg_postinst() { 112alternatives_pkg_postinst() {
95 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 113 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
96 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 114 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
97 fi 115 fi
98} 116}
99 117
100alternatives_pkg_postrm() { 118alternatives_pkg_postrm() {
101 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 119 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
102 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 120 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
103 fi 121 fi
104} 122}
105 123
106EXPORT_FUNCTIONS pkg_postinst pkg_postrm 124EXPORT_FUNCTIONS pkg_postinst pkg_postrm
107

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