cargo_platform/
lib.rs

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1//! Platform definition used by Cargo.
2//!
3//! This defines a [`Platform`] type which is used in Cargo to specify a target platform.
4//! There are two kinds, a named target like `x86_64-apple-darwin`, and a "cfg expression"
5//! like `cfg(any(target_os = "macos", target_os = "ios"))`.
6//!
7//! See `examples/matches.rs` for an example of how to match against a `Platform`.
8//!
9//! > This crate is maintained by the Cargo team for use by the wider
10//! > ecosystem. This crate follows semver compatibility for its APIs.
11//!
12//! [`Platform`]: enum.Platform.html
13
14use std::fmt;
15use std::str::FromStr;
16
17mod cfg;
18mod error;
19
20pub use cfg::{Cfg, CfgExpr};
21pub use error::{ParseError, ParseErrorKind};
22
23/// Platform definition.
24#[derive(Eq, PartialEq, Hash, Ord, PartialOrd, Clone, Debug)]
25pub enum Platform {
26    /// A named platform, like `x86_64-apple-darwin`.
27    Name(String),
28    /// A cfg expression, like `cfg(windows)`.
29    Cfg(CfgExpr),
30}
31
32impl Platform {
33    /// Returns whether the Platform matches the given target and cfg.
34    ///
35    /// The named target and cfg values should be obtained from `rustc`.
36    pub fn matches(&self, name: &str, cfg: &[Cfg]) -> bool {
37        match *self {
38            Platform::Name(ref p) => p == name,
39            Platform::Cfg(ref p) => p.matches(cfg),
40        }
41    }
42
43    fn validate_named_platform(name: &str) -> Result<(), ParseError> {
44        if let Some(ch) = name
45            .chars()
46            .find(|&c| !(c.is_alphanumeric() || c == '_' || c == '-' || c == '.'))
47        {
48            if name.chars().any(|c| c == '(') {
49                return Err(ParseError::new(
50                    name,
51                    ParseErrorKind::InvalidTarget(
52                        "unexpected `(` character, cfg expressions must start with `cfg(`"
53                            .to_string(),
54                    ),
55                ));
56            }
57            return Err(ParseError::new(
58                name,
59                ParseErrorKind::InvalidTarget(format!(
60                    "unexpected character {} in target name",
61                    ch
62                )),
63            ));
64        }
65        Ok(())
66    }
67
68    pub fn check_cfg_attributes(&self, warnings: &mut Vec<String>) {
69        fn check_cfg_expr(expr: &CfgExpr, warnings: &mut Vec<String>) {
70            match *expr {
71                CfgExpr::Not(ref e) => check_cfg_expr(e, warnings),
72                CfgExpr::All(ref e) | CfgExpr::Any(ref e) => {
73                    for e in e {
74                        check_cfg_expr(e, warnings);
75                    }
76                }
77                CfgExpr::Value(ref e) => match e {
78                    Cfg::Name(name) => match name.as_str() {
79                        "test" | "debug_assertions" | "proc_macro" =>
80                            warnings.push(format!(
81                                "Found `{}` in `target.'cfg(...)'.dependencies`. \
82                                 This value is not supported for selecting dependencies \
83                                 and will not work as expected. \
84                                 To learn more visit \
85                                 https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#platform-specific-dependencies",
86                                 name
87                            )),
88                        _ => (),
89                    },
90                    Cfg::KeyPair(name, _) => if name.as_str() == "feature" {
91                        warnings.push(String::from(
92                            "Found `feature = ...` in `target.'cfg(...)'.dependencies`. \
93                             This key is not supported for selecting dependencies \
94                             and will not work as expected. \
95                             Use the [features] section instead: \
96                             https://doc.rust-lang.org/cargo/reference/features.html"
97                        ))
98                    },
99                }
100            }
101        }
102
103        if let Platform::Cfg(cfg) = self {
104            check_cfg_expr(cfg, warnings);
105        }
106    }
107}
108
109impl serde::Serialize for Platform {
110    fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
111    where
112        S: serde::Serializer,
113    {
114        self.to_string().serialize(s)
115    }
116}
117
118impl<'de> serde::Deserialize<'de> for Platform {
119    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
120    where
121        D: serde::Deserializer<'de>,
122    {
123        let s = String::deserialize(deserializer)?;
124        FromStr::from_str(&s).map_err(serde::de::Error::custom)
125    }
126}
127
128impl FromStr for Platform {
129    type Err = ParseError;
130
131    fn from_str(s: &str) -> Result<Platform, ParseError> {
132        if let Some(s) = s.strip_prefix("cfg(").and_then(|s| s.strip_suffix(')')) {
133            s.parse().map(Platform::Cfg)
134        } else {
135            Platform::validate_named_platform(s)?;
136            Ok(Platform::Name(s.to_string()))
137        }
138    }
139}
140
141impl fmt::Display for Platform {
142    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
143        match *self {
144            Platform::Name(ref n) => n.fmt(f),
145            Platform::Cfg(ref e) => write!(f, "cfg({})", e),
146        }
147    }
148}
cargo_platform/lib.rs

cargo_platform/
lib.rs
