On Fri, Sep 30, 2011 at 07:37:48PM +0800, lolilolicon wrote:

config_parser.sh provides functions to support parsing simple config files, pacman.conf in particular. Our scripts should never use a simple eval to get config values such as DBPath.

conf_key_val() is modified from pacman-key's get_from() function. Please note conf_key_val() and conf_key_set() both read config file from stdin, instead of $1.

I don't see the advantage of doing it this way. If/when we add a function like conf_keyval_set() (which actually updates a file) we'll have to ignore this convention and pass the filename, for obvious reasons. At the risk of painting my shed green, I dislike your naming convention, particularly conf_key_set, which doesn't set anything at all. I would have thought that something such as the following would be appropriate: # accessors conf_key_isset() # determines existance of a key w/o an associated value. conf_keyval_get() # gets the value of a key. # mutators conf_key_set() # sets a key without a value, as long as it doesn't exist. conf_keyval_set() # sets a key with a value, as long as it doesn't exist. And of course, accessors return 0/1 to indicate existance, mutators return 0/1 to indicate write success/failure. d

Signed-off-by: lolilolicon --- scripts/library/README | 3 ++ scripts/library/config_parser.sh | 56 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+), 0 deletions(-) create mode 100644 scripts/library/config_parser.sh

diff --git a/scripts/library/README b/scripts/library/README index 1e9c962..4fb70dd 100644 --- a/scripts/library/README +++ b/scripts/library/README @@ -1,6 +1,9 @@ This folder contains code snippets that can be reused by multiple scripts. A brief description of each file follows.

+config_parser.sh: +Parses simple config files such as pacman.conf. + output_format.sh: Provides basic output formatting functions with levels 'msg', 'msg2', 'warning' and 'error'. The 'msg' amd 'msg2' functions print to stdout diff --git a/scripts/library/config_parser.sh b/scripts/library/config_parser.sh new file mode 100644 index 0000000..1d125eb --- /dev/null +++ b/scripts/library/config_parser.sh @@ -0,0 +1,56 @@ +shopt -s extglob + +# Parse value of a non-repeating key from a config file. +# +# stdin: config file +# $1: key - shall not contain '=', or start/end with whitespaces +# $2: default value if not defined in config file [optional] +# return: +# 0 - print value of key +# 1 - print nothing +conf_key_val() { + local key val + while IFS='=' read -r key val; do + # strip whitespaces + key=${key##*([[:space:]])} + key=${key%%*([[:space:]])} + val=${val##*([[:space:]])} + val=${val%%*([[:space:]])}

read is the opportune thing to use here -- it's faster (which surprises me) and more concise. read -r key <<< "$key" read -r val <<< "$val"

+ # ignore comments and invalid lines + [[ ${key:0:1} == '#' || -z $key || -z $val ]] && continue + # return success as soon as a value is found + if [[ $key == "$1" ]]; then + printf '%s' "$val" + return 0 + fi + done + # fallback to default value if specified + if [[ -n $2 ]]; then + printf '%s' "$2" + return 0 + fi + return 1 +} + +# Check whether an on/off key is set (on) in a config file. +# +# stdin: config file +# $1: key - shall not contain '=', or start/end with whitespaces +# return: +# 0 - key is set +# 1 - key is not set +conf_key_set() { + local key + while read -r key; do + # strip whitespaces, ignore comments + key=${key##*([[:space:]])} + key=${key%%*([[:space:]])} + # ignore comments and invalid lines + [[ ${key:0:1} == '#' || -z $key ]] && continue + # return success as soon as the key is found + if [[ $key == "$1" ]]; then + return 0 + fi + done + return 1 +} -- 1.7.6.4

config_parser.sh provides functions to support parsing simple config files, pacman.conf for example. Our scripts should never use a dirty eval to get config values such as DBPath. conf_key_get_val() is modified from pacman-key's get_from() function. All the parser functions implemented read config file from stdin, which makes chaining a breeze. Signed-off-by: lolilolicon --- scripts/library/README | 3 + scripts/library/config_parser.sh | 106 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 109 insertions(+), 0 deletions(-) create mode 100644 scripts/library/config_parser.sh diff --git a/scripts/library/README b/scripts/library/README index 1e9c962..4fb70dd 100644 --- a/scripts/library/README +++ b/scripts/library/README @@ -1,6 +1,9 @@ This folder contains code snippets that can be reused by multiple scripts. A brief description of each file follows. +config_parser.sh: +Parses simple config files such as pacman.conf. + output_format.sh: Provides basic output formatting functions with levels 'msg', 'msg2', 'warning' and 'error'. The 'msg' amd 'msg2' functions print to stdout diff --git a/scripts/library/config_parser.sh b/scripts/library/config_parser.sh new file mode 100644 index 0000000..73e40d3 --- /dev/null +++ b/scripts/library/config_parser.sh @@ -0,0 +1,106 @@ +# Parse value of a single-value key from a config file. +# +# stdin: config file +# $1: key - shall not contain '=', or start/end with whitespaces +# $2: default value if not defined in config file [optional] +# return: +# 0 - print value of key +# 1 - print nothing +conf_key_get_val() { + local key val + while IFS='=' read -r key val; do + # strip whitespaces + IFS=$' \t' read -r key <<< "$key" + IFS=$' \t' read -r val <<< "$val" + # ignore comments and invalid lines + [[ ${key:0:1} == '#' || -z $key || -z $val ]] && continue + # return success as soon as a value is found + if [[ $key == "$1" ]]; then + printf '%s' "$val" + return 0 + fi + done + # fallback to default value if specified + if [[ -n $2 ]]; then + printf '%s' "$2" + return 0 + fi + return 1 +} + +# Parse values of a repeatable, multi-value key from a config file. +# +# stdin: config file +# $1: key - shall not contain '=', or start/end with whitespaces +# $2: default values if not defined in config file [optional] +# return: +# 0 - print values of key, one per line +# 1 - print nothing +conf_key_get_vals() { + local key val vals=() + while IFS='=' read -r key val; do + # strip whitespaces + IFS=$' \t' read -r key <<< "$key" + IFS=$' \t' read -r val <<< "$val" + # ignore comments and invalid lines + [[ ${key:0:1} == '#' || -z $key || -z $val ]] && continue + # keep collecting values + if [[ $key == "$1" ]]; then + vals+=($val) + fi + done + # fallback to default values if specified + (( ${#vals[@]} )) || vals=($2) + (( ${#vals[@]} )) || return 1 + printf '%s\n' "${vals[@]}" + return 0 +} + +# Check whether an on/off key is set in a config file. +# +# stdin: config file +# $1: key - shall not contain '=', or start/end with whitespaces +# return: +# 0 - key is set +# 1 - key is not set +conf_key_isset() { + local key + while read -r key; do + # strip whitespaces + IFS=$' \t' read -r key <<< "$key" + # ignore comments and invalid lines + [[ ${key:0:1} == '#' || -z $key ]] && continue + # return success as soon as the key is found + if [[ $key == "$1" ]]; then + return 0 + fi + done + return 1 +} + +# Print the first section with the specified header from a config file. +# +# stdin: config file +# $1: header string - exact header string of the section +# $2: header pattern - regex matching only header strings +# return: +# 0 - print lines in section +# 1 - print nothing +conf_get_section() { + local line + while read -r line; do + # strip whitespaces + IFS=$' \t' read -r line <<< "$line" + # ignore comments and invalid lines + [[ ${line:0:1} == '#' || -z $line ]] && continue + # print section till EOF or next section + if [[ $line == "$1" ]]; then + while printf '%s\n' "$line"; do + read -r line || break + [[ $line =~ $2 ]] && break + done + return 0 + fi + done + return 1 +} -- 1.7.6.4