1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
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("."))
}