/[gentoo-x86]/eclass/alternatives.eclass
Gentoo

Diff of /eclass/alternatives.eclass

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

Revision 1.4 Revision 1.15
1# Copyright 1999-2003 Gentoo Technologies, Inc. 1# Copyright 1999-2008 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 1.15 2008/09/10 08:10:31 pva Exp $
4 4
5# Author : Alastair Tse <liquidx@gentoo.org> (03 Oct 2003) 5# @ECLASS: alternatives.eclass
6# Short Desc: Creates symlink to the latest version of multiple slotted 6# @MAINTAINER:
7# packages.
8# 7#
9# Long Desc: 8# Original author : Alastair Tse <liquidx@gentoo.org> (03 Oct 2003)
9# @BLURB: Creates symlink to the latest version of multiple slotted packages.
10# @DESCRIPTION:
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,
13# more often than not, the symlink maybe clobbered by the older versions.
10# 14#
11# When a package is SLOT'ed, very often we need to have a symlink to the 15# This eclass provides a convenience function that needs to be given a
12# latest version. However, depending on the order the user has merged them, 16# list of alternatives (descending order of recent-ness) and the symlink.
13# more often than not, the symlink maybe clobbered by the older versions. 17# It will choose the latest version it can find installed and create
18# the desired symlink.
14# 19#
15# This eclass provides a convenience function that needs to be given a 20# There are two ways to use this eclass. First is by declaring two variables
16# list of alternatives (descending order of recent-ness) and the symlink. 21# $SOURCE and $ALTERNATIVES where $SOURCE is the symlink to be created and
17# It will choose the latest version if can find installed and create 22# $ALTERNATIVES is a list of alternatives. Second way is the use the function
18# the desired symlink. 23# alternatives_makesym() like the example below.
24# @EXAMPLE:
25# pkg_postinst() {
26# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
27# }
19# 28#
20# There are two ways to use this eclass. First is by declaring two variables 29# The above example will create a symlink at /usr/bin/python to either
21# $SOURCE and $ALTERNATIVES where $SOURCE is the symlink to be created and 30# /usr/bin/python2.3 or /usr/bin/python2.2. It will choose python2.3 over
22# $ALTERNATIVES is a list of alternatives. Second way is the use the function 31# python2.2 if both exist.
23# alternatives_makesym() like the example below.
24# 32#
25# Example: 33# Alternatively, you can use this function:
26#
27# pkg_postinst() {
28# alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
29# }
30# 34#
31# The above example will create a symlink at /usr/bin/python to either 35# pkg_postinst() {
32# /usr/bin/python2.3 or /usr/bin/python2.2. It will choose python2.3 over 36# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
33# python2.2 if both exist. 37# }
34# 38#
35# Alternatively, you can use this function:
36#
37# pkg_postinst() {
38# alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
39# }
40#
41# This will use bash pathname expansion to fill a list of alternatives it can 39# This will use bash pathname expansion to fill a list of alternatives it can
42# link to. It is probably more robust against version upgrades. You should 40# link to. It is probably more robust against version upgrades. You should
43# consider using this unless you are want to do something special. 41# consider using this unless you are want to do something special.
44#
45ECLASS="alternatives"
46INHERITED="$INHERITED $ECLASS"
47 42
43# @ECLASS-VARIABLE: SOURCE
44# @DESCRIPTION:
45# The symlink to be created
46
47# @ECLASS-VARIABLE: ALTERNATIVES
48# @DESCRIPTION:
49# The list of alternatives
50
51# @FUNCTION: alternatives_auto_makesym
52# @DESCRIPTION:
48# automatic deduction based on a symlink and a regex mask 53# automatic deduction based on a symlink and a regex mask
49alternatives_auto_makesym() { 54alternatives_auto_makesym() {
50 local SYMLINK REGEX ALT myregex 55 local SYMLINK REGEX ALT myregex
51 SYMLINK=$1 56 SYMLINK=$1
52 REGEX=$2 57 REGEX=$2
53 if [ "${REGEX:0:1}" != "/" ] 58 if [ "${REGEX:0:1}" != "/" ]
54 then 59 then
55 #not an absolute path: 60 #not an absolute path:
56 #inherit the root directory of our main link path for our regex search 61 #inherit the root directory of our main link path for our regex search
57 myregex="${SYMLINK%/*}/${REGEX}" 62 myregex="${SYMLINK%/*}/${REGEX}"
58 else 63 else
59 myregex=${REGEX} 64 myregex=${REGEX}
60 fi 65 fi
61 ALT="`echo ${myregex} | sort -r`" 66
67 # sort a space delimited string by converting it to a multiline list
68 # and then run sort -r over it.
69 # make sure we use ${ROOT} because otherwise stage-building will break
70 ALT="$(for i in $(echo ${ROOT}${myregex}); do echo ${i#${ROOT}}; done | sort -r)"
62 alternatives_makesym ${SYMLINK} ${ALT} 71 alternatives_makesym ${SYMLINK} ${ALT}
63} 72}
64 73
65alternatives_makesym() { 74alternatives_makesym() {
66 local ALTERNATIVES="" 75 local ALTERNATIVES=""
67 local SYMLINK="" 76 local SYMLINK=""
68 local alt pref 77 local alt pref
78
69 # usage: alternatives_makesym <resulting symlink> [alternative targets..] 79 # usage: alternatives_makesym <resulting symlink> [alternative targets..]
70 SYMLINK=$1 80 SYMLINK=$1
71 pref=${ROOT:0:${#ROOT}-1} 81 # this trick removes the trailing / from ${ROOT}
82 pref=$(echo ${ROOT} | sed 's:/$::')
72 shift 83 shift
73 ALTERNATIVES=$@ 84 ALTERNATIVES=$@
74 85
75 # step through given alternatives from first to last 86 # step through given alternatives from first to last
76 # and if one exists, link it and finish. 87 # and if one exists, link it and finish.
77 88
78 for alt in ${ALTERNATIVES}; do 89 for alt in ${ALTERNATIVES}; do
79 if [ -f "${pref}${alt}" ]; then 90 if [ -f "${pref}${alt}" ]; then
80 einfo "Linking ${alt} to ${pref}${SYMLINK}"
81 [ -L "${pref}${SYMLINK}" ] && rm -f ${pref}${SYMLINK}
82 #are files in same directory? 91 #are files in same directory?
83 if [ "${alt%/*}" = "${SYMLINK%/*}" ] 92 if [ "${alt%/*}" = "${SYMLINK%/*}" ]
84 then 93 then
85 #yes; strip leading dirname from alt to create relative symlink 94 #yes; strip leading dirname from alt to create relative symlink
95 einfo "Linking ${alt} to ${pref}${SYMLINK} (relative)"
86 ln -s ${alt##*/} ${pref}${SYMLINK} 96 ln -sf ${alt##*/} ${pref}${SYMLINK}
87 else 97 else
88 #no; keep absolute path 98 #no; keep absolute path
99 einfo "Linking ${alt} to ${pref}${SYMLINK} (absolute)"
89 ln -s ${pref}${alt} ${pref}${SYMLINK} 100 ln -sf ${pref}${alt} ${pref}${SYMLINK}
90 fi 101 fi
91 break 102 break
92 fi 103 fi
93 done 104 done
94 105
95 # report any errors 106 # report any errors
96 if [ ! -L ${pref}${SYMLINK} ]; then 107 if [ ! -L ${pref}${SYMLINK} ]; then
97 ewarn "Unable to establish ${pref}${SYMLINK} symlink" 108 ewarn "Unable to establish ${pref}${SYMLINK} symlink"
98 else 109 else
99 # we need to check for either the target being in relative path form 110 # we need to check for either the target being in relative path form
100 # or absolute path form 111 # or absolute path form
101 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \ 112 if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \
102 ! -f "`readlink ${pref}${SYMLINK}`" ]; then 113 ! -f "`readlink ${pref}${SYMLINK}`" ]; then
103 ewarn "${pref}${SYMLINK} is a dead symlink." 114 ewarn "Removing dead symlink ${pref}${SYMLINK}"
115 rm -f ${pref}${SYMLINK}
104 fi 116 fi
105 fi 117 fi
106} 118}
107 119
120# @FUNCTION: alernatives-pkg_postinst
121# @DESCRIPTION:
122# The alternatives pkg_postinst, this function will be exported
108alternatives_pkg_postinst() { 123alternatives_pkg_postinst() {
109 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 124 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
110 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 125 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
111 fi 126 fi
112} 127}
113 128
129# @FUNCTION: alternatives_pkg_postrm
130# @DESCRIPTION:
131# The alternatives pkg_postrm, this function will be exported
114alternatives_pkg_postrm() { 132alternatives_pkg_postrm() {
115 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then 133 if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
116 alternatives_makesym ${SOURCE} ${ALTERNATIVES} 134 alternatives_makesym ${SOURCE} ${ALTERNATIVES}
117 fi 135 fi
118} 136}
119 137
120EXPORT_FUNCTIONS pkg_postinst pkg_postrm 138EXPORT_FUNCTIONS pkg_postinst pkg_postrm
121

Legend:
Removed from v.1.4  
changed lines
  Added in v.1.15

  ViewVC Help
Powered by ViewVC 1.1.20