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//! Implement a configuration source based on command-line arguments.
use once_cell::sync::Lazy;
use regex::Regex;
/// A CmdLine holds a set of command-line arguments that augment a
/// configuration.
///
/// These arguments are formatted in toml, and concatenated into a
/// single toml object. With arguments of the form "key=bareword",
/// the bareword is quoted for convenience.
#[derive(Debug, Clone)]
pub struct CmdLine {
/// String for decorating Values.
//
// TODO(nickm): not yet used.
#[allow(dead_code)]
name: String,
/// List of toml lines as given on the command line.
contents: Vec<String>,
}
impl Default for CmdLine {
fn default() -> Self {
Self::new()
impl CmdLine {
/// Make a new empty command-line
pub fn new() -> Self {
CmdLine {
name: "command line".to_string(),
contents: Vec::new(),
/// Add a single line of toml to the configuration.
pub fn push_toml_line(&mut self, line: String) {
self.contents.push(line);
/// Try to adjust the contents of a toml deserialization error so
/// that instead it refers to a single command-line argument.
fn convert_toml_error(
&self,
toml_str: &str,
error_message: &str,
span: &Option<std::ops::Range<usize>>,
) -> String {
// Function to translate a string index to a 0-offset line number.
let linepos = |idx| toml_str.bytes().take(idx).filter(|b| *b == b'\n').count();
// Find the source position as a line within toml_str, and convert that
// to an index into self.contents.
let source_line = span
.as_ref()
.and_then(|range| {
let startline = linepos(range.start);
let endline = linepos(range.end);
(startline == endline).then_some(startline)
})
.and_then(|pos| self.contents.get(pos));
match (source_line, span.as_ref()) {
(Some(source), _) => {
format!("Couldn't parse command line: {error_message} in {source:?}")
(None, Some(range)) if toml_str.get(range.clone()).is_some() => format!(
"Couldn't parse command line: {error_message} within {:?}",
&toml_str[range.clone()]
),
_ => format!("Couldn't parse command line: {error_message}"),
/// Compose elements of this cmdline into a single toml string.
fn build_toml(&self) -> String {
let mut toml_s = String::new();
for line in &self.contents {
toml_s.push_str(tweak_toml_bareword(line).as_ref().unwrap_or(line));
toml_s.push('\n');
toml_s
impl figment::Provider for CmdLine {
fn metadata(&self) -> figment::Metadata {
figment::Metadata::named("command line")
fn data(&self) -> figment::Result<figment::value::Map<figment::Profile, figment::value::Dict>> {
let toml_str = self.build_toml();
let toml: toml::Value = toml::from_str(&toml_str).map_err(|toml_err| {
self.convert_toml_error(&toml_str, toml_err.message(), &toml_err.span())
})?;
figment::providers::Serialized::defaults(toml).data()
/// If `s` is a string of the form "keyword=bareword", return a new string
/// where `bareword` is quoted. Otherwise return None.
/// This isn't a smart transformation outside the context of 'config',
/// since many serde formats don't do so good a job when they get a
/// string when they wanted a number or whatever. But 'config' is
/// pretty happy to convert strings to other stuff.
fn tweak_toml_bareword(s: &str) -> Option<String> {
/// Regex to match a keyword=bareword item.
static RE: Lazy<Regex> = Lazy::new(|| {
Regex::new(
r#"(?x:
^
[ \t]*
# first capture group: dotted barewords
((?:[a-zA-Z0-9_\-]+\.)*
[a-zA-Z0-9_\-]+)
[ \t]*=[ \t]*
# second group: one bareword without hyphens
([a-zA-Z0-9_]+)
$)"#,
)
.expect("Built-in regex compilation failed")
});
RE.captures(s).map(|c| format!("{}=\"{}\"", &c[1], &c[2]))
#[cfg(test)]
mod test {
// @@ begin test lint list maintained by maint/add_warning @@
#![allow(clippy::bool_assert_comparison)]
#![allow(clippy::clone_on_copy)]
#![allow(clippy::dbg_macro)]
#![allow(clippy::mixed_attributes_style)]
#![allow(clippy::print_stderr)]
#![allow(clippy::print_stdout)]
#![allow(clippy::single_char_pattern)]
#![allow(clippy::unwrap_used)]
#![allow(clippy::unchecked_duration_subtraction)]
#![allow(clippy::useless_vec)]
#![allow(clippy::needless_pass_by_value)]
//! <!-- @@ end test lint list maintained by maint/add_warning @@ -->
use super::*;
use figment::Provider as _;
#[test]
fn bareword_expansion() {
assert_eq!(tweak_toml_bareword("dsfklj"), None);
assert_eq!(tweak_toml_bareword("=99"), None);
assert_eq!(tweak_toml_bareword("=[1,2,3]"), None);
assert_eq!(tweak_toml_bareword("a=b-c"), None);
assert_eq!(tweak_toml_bareword("a=bc"), Some("a=\"bc\"".into()));
assert_eq!(tweak_toml_bareword("a=b_c"), Some("a=\"b_c\"".into()));
assert_eq!(
tweak_toml_bareword("hello.there.now=a_greeting"),
Some("hello.there.now=\"a_greeting\"".into())
);
fn conv_toml_error() {
let mut cl = CmdLine::new();
cl.push_toml_line("Hello=world".to_string());
cl.push_toml_line("Hola=mundo".to_string());
cl.push_toml_line("Bonjour=monde".to_string());
let toml_s = cl.build_toml();
&cl.convert_toml_error(&toml_s, "Nice greeting", &Some(0..13)),
"Couldn't parse command line: Nice greeting in \"Hello=world\""
&cl.convert_toml_error(&toml_s, "Nice greeting", &Some(99..333)),
"Couldn't parse command line: Nice greeting"
&cl.convert_toml_error(&toml_s, "Nice greeting with a thing", &Some(0..13)),
"Couldn't parse command line: Nice greeting with a thing in \"Hello=world\""
fn parse_good() {
let mut cl = CmdLine::default();
cl.push_toml_line("a=3".to_string());
cl.push_toml_line("bcd=hello".to_string());
cl.push_toml_line("ef=\"gh i\"".to_string());
cl.push_toml_line("w=[1,2,3]".to_string());
let v = cl
.data()
.unwrap()
.remove(&figment::Profile::Default)
.unwrap();
assert_eq!(v["a"], "3".into());
assert_eq!(v["bcd"], "hello".into());
assert_eq!(v["ef"], "gh i".into());
assert_eq!(v["w"], vec![1, 2, 3].into());
fn parse_bad() {
cl.push_toml_line("x=1 1 1 1 1".to_owned());
let v = cl.data();
assert!(v.is_err());