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

cargo_platform/
lib.rs
