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use std::fmt;
use std::borrow::Cow;
use std::path::{Path, PathBuf};
use std::panic::Location;
use crate::Profile;
/// Metadata about a configuration value: its source's name and location.
///
/// # Overview
///
/// Every [`Value`] produced by a [`Figment`] is [`Tag`]ed with `Metadata`
/// by its producing [`Provider`]. The metadata consists of:
///
/// * A name for the source, e.g. "TOML File".
/// * The [`Source`] itself, if it is known.
/// * A default or custom [interpolater](#interpolation).
/// * A source [`Location`] where a value's provider was added to the
/// containing figment, if it is known.
///
/// This information is used to produce insightful error messages as well as to
/// generate values like [`RelativePathBuf`] that know about their configuration
/// source.
///
/// [`Location`]: std::panic::Location
///
/// ## Errors
///
/// [`Error`]s produced by [`Figment`]s contain the `Metadata` for the value
/// that caused the error. The `Display` implementation for `Error` uses the
/// metadata's interpolater to display the path to the key for the value that
/// caused the error.
///
/// ## Interpolation
///
/// Interpolation takes a figment profile and key path (`a.b.c`) and turns it
/// into a source-native path. The default interpolater returns a figment key
/// path prefixed with the profile if the profile is custom:
///
/// ```text
/// ${profile}.${a}.${b}.${c}
/// ```
///
/// Providers are free to implement any interpolater for their metadata. For
/// example, the interpolater for [`Env`] uppercases each path key:
///
/// ```rust
/// use figment::Metadata;
///
/// let metadata = Metadata::named("environment variable(s)")
/// .interpolater(|profile, path| {
/// let keys: Vec<_> = path.iter()
/// .map(|k| k.to_ascii_uppercase())
/// .collect();
///
/// format!("{}", keys.join("."))
/// });
///
/// let profile = figment::Profile::Default;
/// let interpolated = metadata.interpolate(&profile, &["key", "path"]);
/// assert_eq!(interpolated, "KEY.PATH");
/// ```
///
/// [`Provider`]: crate::Provider
/// [`Error`]: crate::Error
/// [`Figment`]: crate::Figment
/// [`RelativePathBuf`]: crate::value::magic::RelativePathBuf
/// [`value`]: crate::value::Value
/// [`Tag`]: crate::value::Tag
/// [`Env`]: crate::providers::Env
#[derive(Debug, Clone)]
pub struct Metadata {
/// The name of the configuration source for a given value.
pub name: Cow<'static, str>,
/// The source of the configuration value, if it is known.
pub source: Option<Source>,
/// The source location where this value's provider was added to the
/// containing figment, if it is known.
pub provide_location: Option<&'static Location<'static>>,
interpolater: Box<dyn Interpolator>,
}
impl Metadata {
/// Creates a new `Metadata` with the given `name` and `source`.
///
/// # Example
///
/// ```rust
/// use figment::Metadata;
///
/// let metadata = Metadata::from("AWS Config Store", "path/to/value");
/// assert_eq!(metadata.name, "AWS Config Store");
/// assert_eq!(metadata.source.unwrap().custom(), Some("path/to/value"));
/// ```
#[inline(always)]
pub fn from<N, S>(name: N, source: S) -> Self
where N: Into<Cow<'static, str>>, S: Into<Source>
{
Metadata::named(name).source(source)
}
/// Creates a new `Metadata` with the given `name` and no source.
///
/// # Example
///
/// ```rust
/// use figment::Metadata;
///
/// let metadata = Metadata::named("AWS Config Store");
/// assert_eq!(metadata.name, "AWS Config Store");
/// assert!(metadata.source.is_none());
/// ```
#[inline]
pub fn named<T: Into<Cow<'static, str>>>(name: T) -> Self {
Metadata { name: name.into(), ..Metadata::default() }
}
/// Sets the `source` of `self` to `Some(source)`.
///
/// # Example
///
/// ```rust
/// use figment::Metadata;
///
/// let metadata = Metadata::named("AWS Config Store").source("config/path");
/// assert_eq!(metadata.name, "AWS Config Store");
/// assert_eq!(metadata.source.unwrap().custom(), Some("config/path"));
/// ```
#[inline(always)]
pub fn source<S: Into<Source>>(mut self, source: S) -> Self {
self.source = Some(source.into());
self
}
/// Sets the `interpolater` of `self` to the function `f`. The interpolater
/// can be invoked via [`Metadata::interpolate()`].
///
/// # Example
///
/// ```rust
/// use figment::Metadata;
///
/// let metadata = Metadata::named("environment variable(s)")
/// .interpolater(|profile, path| {
/// let keys: Vec<_> = path.iter()
/// .map(|k| k.to_ascii_uppercase())
/// .collect();
///
/// format!("{}", keys.join("."))
/// });
///
/// let profile = figment::Profile::Default;
/// let interpolated = metadata.interpolate(&profile, &["key", "path"]);
/// assert_eq!(interpolated, "KEY.PATH");
/// ```
#[inline(always)]
pub fn interpolater<I: Clone + Send + Sync + 'static>(mut self, f: I) -> Self
where I: Fn(&Profile, &[&str]) -> String
{
self.interpolater = Box::new(f);
self
}
/// Runs the interpolater in `self` on `profile` and `keys`.
///
/// # Example
///
/// ```rust
/// use figment::{Metadata, Profile};
///
/// let url = "ftp://config.dev";
/// let md = Metadata::named("Network").source(url)
/// .interpolater(move |profile, keys| match profile.is_custom() {
/// true => format!("{}/{}/{}", url, profile, keys.join("/")),
/// false => format!("{}/{}", url, keys.join("/")),
/// });
///
/// let interpolated = md.interpolate(&Profile::Default, &["key", "path"]);
/// assert_eq!(interpolated, "ftp://config.dev/key/path");
///
/// let profile = Profile::new("static");
/// let interpolated = md.interpolate(&profile, &["key", "path"]);
/// assert_eq!(interpolated, "ftp://config.dev/static/key/path");
/// ```
pub fn interpolate<K: AsRef<str>>(&self, profile: &Profile, keys: &[K]) -> String {
let keys: Vec<_> = keys.iter().map(|k| k.as_ref()).collect();
(self.interpolater)(profile, &keys)
}
}
impl PartialEq for Metadata {
fn eq(&self, other: &Self) -> bool {
self.name == other.name && self.source == other.source
}
}
impl Default for Metadata {
fn default() -> Self {
Self {
name: "Default".into(),
source: None,
provide_location: None,
interpolater: Box::new(default_interpolater),
}
}
}
/// The source for a configuration value.
///
/// The `Source` of a given value can be determined via that value's
/// [`Metadata.source`](Metadata#structfield.source) retrievable via the value's
/// [`Tag`] (via [`Value::tag()`] or via the magic value [`Tagged`]) and
/// [`Figment::get_metadata()`].
///
/// [`Tag`]: crate::value::Tag
/// [`Value::tag()`]: crate::value::Value::tag()
/// [`Tagged`]: crate::value::magic::Tagged
/// [`Figment::get_metadata()`]: crate::Figment::get_metadata()
#[non_exhaustive]
#[derive(PartialEq, Debug, Clone)]
pub enum Source {
/// A file: the path to the file.
File(PathBuf),
/// Some programatic value: the source location.
Code(&'static Location<'static>),
/// A custom source all-together.
Custom(String),
}
impl Source {
/// Returns the path to the source file if `self.kind` is `Kind::File`.
///
/// # Example
///
/// ```rust
/// use std::path::Path;
/// use figment::Source;
///
/// let source = Source::from(Path::new("a/b/c.txt"));
/// assert_eq!(source.file_path(), Some(Path::new("a/b/c.txt")));
/// ```
pub fn file_path(&self) -> Option<&Path> {
match self {
Source::File(ref p) => Some(p),
_ => None,
}
}
/// Returns the location to the source code if `self` is `Source::Code`.
///
/// # Example
///
/// ```rust
/// use std::panic::Location;
///
/// use figment::Source;
///
/// let location = Location::caller();
/// let source = Source::Code(location);
/// assert_eq!(source.code_location(), Some(location));
/// ```
pub fn code_location(&self) -> Option<&'static Location<'static>> {
match self {
Source::Code(s) => Some(s),
_ => None
}
}
/// Returns the custom source location if `self` is `Source::Custom`.
///
/// # Example
///
/// ```rust
/// use figment::Source;
///
/// let source = Source::Custom("ftp://foo".into());
/// assert_eq!(source.custom(), Some("ftp://foo"));
/// ```
pub fn custom(&self) -> Option<&str> {
match self {
Source::Custom(ref c) => Some(c),
_ => None,
}
}
}
/// Displays the source. Location and custom sources are displayed directly.
/// File paths are displayed relative to the current working directory if the
/// relative path is shorter than the complete path.
impl fmt::Display for Source {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Source::File(p) => {
use {std::env::current_dir, crate::util::diff_paths};
match current_dir().ok().and_then(|cwd| diff_paths(p, &cwd)) {
Some(r) if r.iter().count() < p.iter().count() => r.display().fmt(f),
Some(_) | None => p.display().fmt(f)
}
}
Source::Code(l) => l.fmt(f),
Source::Custom(c) => c.fmt(f),
}
}
}
impl From<&Path> for Source {
fn from(path: &Path) -> Source {
Source::File(path.into())
}
}
impl From<&'static Location<'static>> for Source {
fn from(location: &'static Location<'static>) -> Source {
Source::Code(location)
}
}
impl From<&str> for Source {
fn from(string: &str) -> Source {
Source::Custom(string.into())
}
}
impl From<String> for Source {
fn from(string: String) -> Source {
Source::Custom(string)
}
}
crate::util::cloneable_fn_trait!(
Interpolator: Fn(&Profile, &[&str]) -> String + Send + Sync + 'static
);
fn default_interpolater(profile: &Profile, keys: &[&str]) -> String {
format!("{}.{}", profile, keys.join("."))
}