* Re: [gentoo-dev] estack_{push,pop}: cool new helpers or over engineering?
@ 2011-12-14 23:49 99% ` Mike Frysinger
0 siblings, 0 replies; 1+ results
From: Mike Frysinger @ 2011-12-14 23:49 UTC (permalink / raw
To: gentoo-dev
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some people pointed out typos/bugs, so here's v2
-mike
--- eutils.eclass 14 Dec 2011 17:36:18 -0000 1.372
+++ eutils.eclass 14 Dec 2011 23:46:37 -0000
@@ -100,6 +100,54 @@ esvn_clean() {
find "$@" -type d -name '.svn' -prune -print0 | xargs -0 rm -rf
}
+# @FUNCTION: estack_push
+# @USAGE: <stack> [items to push]
+# @DESCRIPTION:
+# Push any number of items onto the specified stack. Pick a name that
+# is a valid variable (i.e. stick to alphanumerics), and push as many
+# items as you like onto the stack at once.
+#
+# The following code snippet will echo 5, then 4, then 3, then ...
+# @CODE
+# estack_push mystack 1 2 3 4 5
+# while estack_pop mystack i ; do
+# echo ${i}
+# done
+# @CODE
+estack_push() {
+ [[ $# -eq 0 ]] && die "estack_push: incorrect # of arguments"
+ local stack_name="__ESTACK_$1__" ; shift
+ eval ${stack_name}+=\( \"\$@\" \)
+}
+
+# @FUNCTION: estack_pop
+# @USAGE: <stack> [variable]
+# @DESCRIPTION:
+# Pop a single item off the specified stack. If a variable is specified,
+# the popped item is stored there. If no more items are available, return
+# 1, else return 0. See estack_push for more info.
+estack_pop() {
+ ( [[ $# -eq 0 ]] || [[ $# -gt 2 ]] ) && die "estack_pop: incorrect # of arguments"
+
+ # We use the fugly __estack_xxx var names to avoid collision with
+ # passing back the return value. If we used "local i" and the
+ # caller ran `estack_pop ... i`, we'd end up setting the local
+ # copy of "i" rather than the caller's copy. The __estack_xxx
+ # garbage is preferable to using $1/$2 everywhere as that is a
+ # bit harder to read.
+ local __estack_name="__ESTACK_$1__" ; shift
+ local __estack_retvar=$1 ; shift
+ eval local __estack_i=\${#${__estack_name}[@]}
+ # Don't warn -- let the caller interpret this as a failure
+ # or as normal behavior (akin to `shift`)
+ [[ $(( --__estack_i )) -eq -1 ]] && return 1
+
+ if [[ -n ${__estack_retvar} ]] ; then
+ eval ${__estack_retvar}=\"\${${__estack_name}[${__estack_i}]}\"
+ fi
+ eval unset ${__estack_name}[${__estack_i}]
+}
+
# @FUNCTION: eshopts_push
# @USAGE: [options to `set` or `shopt`]
# @DESCRIPTION:
@@ -126,15 +174,14 @@ esvn_clean() {
eshopts_push() {
# have to assume __ESHOPTS_SAVE__ isn't screwed with
# as a `declare -a` here will reset its value
- local i=${#__ESHOPTS_SAVE__[@]}
if [[ $1 == -[su] ]] ; then
- __ESHOPTS_SAVE__[$i]=$(shopt -p)
+ estack_push eshopts "$(shopt -p)"
[[ $# -eq 0 ]] && return 0
shopt "$@" || die "eshopts_push: bad options to shopt: $*"
else
- __ESHOPTS_SAVE__[$i]=$-
+ estack_push eshopts $-
[[ $# -eq 0 ]] && return 0
set "$@" || die "eshopts_push: bad options to set: $*"
fi
}
@@ -144,19 +191,36 @@ eshopts_push() {
# Restore the shell options to the state saved with the corresponding
# eshopts_push call. See that function for more details.
eshopts_pop() {
- [[ $# -ne 0 ]] && die "eshopts_pop takes no arguments"
- local i=$(( ${#__ESHOPTS_SAVE__[@]} - 1 ))
- [[ ${i} -eq -1 ]] && die "eshopts_{push,pop}: unbalanced pair"
- local s=${__ESHOPTS_SAVE__[$i]}
- unset __ESHOPTS_SAVE__[$i]
+ local s
+ estack_pop eshopts s || die "${FUNCNAME}: unbalanced push"
if [[ ${s} == "shopt -"* ]] ; then
eval "${s}" || die "eshopts_pop: sanity: invalid shopt options: ${s}"
else
set +$- || die "eshopts_pop: sanity: invalid shell settings: $-"
set -${s} || die "eshopts_pop: sanity: unable to restore saved shell settings: ${s}"
fi
}
+# @FUNCTION: eumask_push
+# @USAGE: <new umask>
+# @DESCRIPTION:
+# Set the umask to the new value specified while saving the previous
+# value onto a stack. Useful for temporarily changing the umask.
+eumask_push() {
+ estack_push eumask "$(umask)"
+ umask "$@" || die "${FUNCNAME}: bad options to umask: $*"
+}
+
+# @FUNCTION: eumask_pop
+# @USAGE:
+# @DESCRIPTION:
+# Restore the previous umask state.
+eumask_pop() {
+ local s
+ estack_pop eumask s || die "${FUNCNAME}: unbalanced push"
+ umask ${s} || die "${FUNCNAME}: sanity: could not restore umask: ${s}"
+}
+
# @VARIABLE: EPATCH_SOURCE
# @DESCRIPTION:
# Default directory to search for patches.
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2011-12-14 22:25 [gentoo-dev] estack_{push,pop}: cool new helpers or over engineering? Mike Frysinger
2011-12-14 23:49 99% ` Mike Frysinger
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