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Revision 1.10 - (hide annotations) (download)
Wed Jul 6 20:20:03 2005 UTC (9 years, 5 months ago) by agriffis
Branch: MAIN
Changes since 1.9: +1 -2 lines
Remove ECLASS= and INHERITED= which haven't been necessary for a long time now

1 vapier 1.9 # Copyright 1999-2004 Gentoo Foundation
2 liquidx 1.1 # Distributed under the terms of the GNU General Public License v2
3 agriffis 1.10 # $Header: /var/cvsroot/gentoo-x86/eclass/alternatives.eclass,v 1.9 2004/06/25 00:39:48 vapier Exp $
4 liquidx 1.1
5     # Author : Alastair Tse <liquidx@gentoo.org> (03 Oct 2003)
6     # Short Desc: Creates symlink to the latest version of multiple slotted
7     # packages.
8     #
9     # Long Desc:
10     #
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.
14     #
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.
17     # It will choose the latest version if can find installed and create
18     # the desired symlink.
19     #
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
22     # $ALTERNATIVES is a list of alternatives. Second way is the use the function
23     # alternatives_makesym() like the example below.
24     #
25     # Example:
26     #
27     # pkg_postinst() {
28     # alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
29     # }
30     #
31     # The above example will create a symlink at /usr/bin/python to either
32     # /usr/bin/python2.3 or /usr/bin/python2.2. It will choose python2.3 over
33     # python2.2 if both exist.
34     #
35     # Alternatively, you can use this function:
36     #
37     # pkg_postinst() {
38     # alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
39     # }
40     #
41     # This will use bash pathname expansion to fill a list of alternatives it can
42     # link to. It is probably more robust against version upgrades. You should
43     # consider using this unless you are want to do something special.
44     #
45     INHERITED="$INHERITED $ECLASS"
46    
47     # automatic deduction based on a symlink and a regex mask
48     alternatives_auto_makesym() {
49 liquidx 1.6 local SYMLINK REGEX ALT myregex
50     SYMLINK=$1
51 liquidx 1.1 REGEX=$2
52 liquidx 1.6 if [ "${REGEX:0:1}" != "/" ]
53     then
54     #not an absolute path:
55     #inherit the root directory of our main link path for our regex search
56     myregex="${SYMLINK%/*}/${REGEX}"
57 liquidx 1.1 else
58 liquidx 1.6 myregex=${REGEX}
59     fi
60 liquidx 1.8
61 liquidx 1.6 # sort a space delimited string by converting it to a multiline list
62     # and then run sort -r over it.
63 liquidx 1.8 # make sure we use ${ROOT} because otherwise stage-building will break
64     ALT="$(for i in $(echo ${ROOT}${myregex}); do echo ${i#${ROOT}}; done | sort -r)"
65 liquidx 1.6 alternatives_makesym ${SYMLINK} ${ALT}
66 liquidx 1.1 }
67    
68     alternatives_makesym() {
69     local ALTERNATIVES=""
70 liquidx 1.6 local SYMLINK=""
71     local alt pref
72 liquidx 1.8
73 liquidx 1.1 # usage: alternatives_makesym <resulting symlink> [alternative targets..]
74 liquidx 1.6 SYMLINK=$1
75 liquidx 1.8 # this trick removes the trailing / from ${ROOT}
76     pref=$(echo ${ROOT} | sed 's:/$::')
77 liquidx 1.1 shift
78     ALTERNATIVES=$@
79    
80     # step through given alternatives from first to last
81     # and if one exists, link it and finish.
82    
83     for alt in ${ALTERNATIVES}; do
84 liquidx 1.6 if [ -f "${pref}${alt}" ]; then
85     #are files in same directory?
86     if [ "${alt%/*}" = "${SYMLINK%/*}" ]
87     then
88     #yes; strip leading dirname from alt to create relative symlink
89 liquidx 1.8 einfo "Linking ${alt} to ${pref}${SYMLINK} (relative)"
90 liquidx 1.7 ln -sf ${alt##*/} ${pref}${SYMLINK}
91 liquidx 1.6 else
92     #no; keep absolute path
93 liquidx 1.8 einfo "Linking ${alt} to ${pref}${SYMLINK} (absolute)"
94 liquidx 1.7 ln -sf ${pref}${alt} ${pref}${SYMLINK}
95 liquidx 1.1 fi
96     break
97     fi
98     done
99    
100     # report any errors
101 liquidx 1.6 if [ ! -L ${pref}${SYMLINK} ]; then
102     ewarn "Unable to establish ${pref}${SYMLINK} symlink"
103     else
104     # we need to check for either the target being in relative path form
105     # or absolute path form
106     if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \
107     ! -f "`readlink ${pref}${SYMLINK}`" ]; then
108     ewarn "${pref}${SYMLINK} is a dead symlink."
109     fi
110 liquidx 1.1 fi
111     }
112    
113     alternatives_pkg_postinst() {
114     if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
115     alternatives_makesym ${SOURCE} ${ALTERNATIVES}
116     fi
117     }
118    
119     alternatives_pkg_postrm() {
120     if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
121     alternatives_makesym ${SOURCE} ${ALTERNATIVES}
122     fi
123     }
124    
125     EXPORT_FUNCTIONS pkg_postinst pkg_postrm

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