rpm query is slow, cache it

diff --git a/shrc.sh b/shrc.sh
index a384ae846f5a20ac59b178afcd9bc8ef262202df..e9ea716b8cf4c2cc78974a6e4436c916ebecc465 100755 (executable)
--- a/shrc.sh
+++ b/shrc.sh
@@ -286,7 +286,10 @@ __bash_prompt_command() {
        local LIGHT_GRAY="\[\033[0;37m\]"
        local COLOR_NONE="\[\e[0m\]"
 
+       # if we are in rpm subdir and have exactly one .spec in the dir, include package version
+       __package_update_rpmversion
        local rpmver=$(__package_rpmversion)
+
        local prompt="${BLUE}[${RED}\w${GREEN}${rpmver:+($rpmver)}$(__bash_parse_git_branch)${BLUE}]${COLOR_NONE} "
        if [ $previous_return_value -eq 0 ]; then
                PS1="${prompt}➔ "
@@ -333,10 +336,46 @@ __bash_parse_git_branch() {
        fi
 }
 
-# if we are in rpm subdir and have exactly one .spec in the dir, include package version
-__package_rpmversion() {
-       if [[ $PWD =~ $(rpm -E %_topdir) ]] && [ "$(\ls *.spec 2>/dev/null | wc -w)" = 1 ]; then
-               # give only first version (ignore subpackages)
-               rpm --define "_specdir $PWD" --specfile *.spec -q --qf '%{VERSION}\n' | head -n1
+# cache requires bash 4.x
+declare -A __package_update_rpmversion_cache
+__package_update_rpmversion() {
+       # extract vars from cache
+       set -- ${__package_update_rpmversion_cache[$PWD]}
+       local specfile=$1 version=$2 mtime=$3
+
+       # invalidate cache
+       if [ -f "$specfile" ]; then
+               local stat
+               stat=$(stat -c %Y $specfile)
+               if [ $mtime ] && [ $stat -gt $mtime ]; then
+                       unset version
+               fi
+               mtime=$stat
+       else
+               # reset cache, .spec may be renamed
+               unset version specfile
        fi
+
+       # we have cached version
+       test -n "$version" && return
+
+       # needs to be one file
+       specfile=${specfile:-$(\ls *.spec 2>/dev/null)}
+       if [ ! -f "$specfile" ]; then
+               unset __package_update_rpmversion_cache[$PWD]
+               return
+       fi
+
+       mtime=${mtime:-$(stat -c %Y $specfile)}
+
+       # give only first version (ignore subpackages)
+       version=$(rpm --define "_specdir $PWD" --specfile $specfile -q --qf '%{VERSION}\n' | head -n1)
+       __package_update_rpmversion_cache[$PWD]="$specfile $version $mtime"
+}
+
+__package_rpmversion() {
+       # extract vars from cache
+       set -- ${__package_update_rpmversion_cache[$PWD]}
+       # print version
+       echo $2
 }