//! Platform definition used by Cargo.
//!
//! This defines a [`Platform`] type which is used in Cargo to specify a target platform.
//! There are two kinds, a named target like `x86_64-apple-darwin`, and a "cfg expression"
//! like `cfg(any(target_os = "macos", target_os = "ios"))`.
//!
//! See `examples/matches.rs` for an example of how to match against a `Platform`.
//!
//! [`Platform`]: enum.Platform.html
use std::fmt;
use std::str::FromStr;
mod cfg;
mod error;
pub use cfg::{Cfg, CfgExpr};
pub use error::{ParseError, ParseErrorKind};
/// Platform definition.
#[derive(Eq, PartialEq, Hash, Ord, PartialOrd, Clone, Debug)]
pub enum Platform {
/// A named platform, like `x86_64-apple-darwin`.
Name(String),
/// A cfg expression, like `cfg(windows)`.
Cfg(CfgExpr),
}
impl Platform {
/// Returns whether the Platform matches the given target and cfg.
///
/// The named target and cfg values should be obtained from `rustc`.
pub fn matches(&self, name: &str, cfg: &[Cfg]) -> bool {
match *self {
Platform::Name(ref p) => p == name,
Platform::Cfg(ref p) => p.matches(cfg),
}
}
fn validate_named_platform(name: &str) -> Result<(), ParseError> {
if let Some(ch) = name
.chars()
.find(|&c| !(c.is_alphanumeric() || c == '_' || c == '-' || c == '.'))
{
if name.chars().any(|c| c == '(') {
return Err(ParseError::new(
name,
ParseErrorKind::InvalidTarget(
"unexpected `(` character, cfg expressions must start with `cfg(`"
.to_string(),
),
));
}
return Err(ParseError::new(
name,
ParseErrorKind::InvalidTarget(format!(
"unexpected character {} in target name",
ch
)),
));
}
Ok(())
}
pub fn check_cfg_attributes(&self, warnings: &mut Vec<String>) {
fn check_cfg_expr(expr: &CfgExpr, warnings: &mut Vec<String>) {
match *expr {
CfgExpr::Not(ref e) => check_cfg_expr(e, warnings),
CfgExpr::All(ref e) | CfgExpr::Any(ref e) => {
for e in e {
check_cfg_expr(e, warnings);
}
}
CfgExpr::Value(ref e) => match e {
Cfg::Name(name) => match name.as_str() {
"test" | "debug_assertions" | "proc_macro" =>
warnings.push(format!(
"Found `{}` in `target.'cfg(...)'.dependencies`. \
This value is not supported for selecting dependencies \
and will not work as expected. \
To learn more visit \
https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#platform-specific-dependencies",
name
)),
_ => (),
},
Cfg::KeyPair(name, _) => if name.as_str() == "feature" {
warnings.push(String::from(
"Found `feature = ...` in `target.'cfg(...)'.dependencies`. \
This key is not supported for selecting dependencies \
and will not work as expected. \
Use the [features] section instead: \
https://doc.rust-lang.org/cargo/reference/features.html"
))
},
}
}
}
if let Platform::Cfg(cfg) = self {
check_cfg_expr(cfg, warnings);
}
}
}
impl serde::Serialize for Platform {
fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
self.to_string().serialize(s)
}
}
impl<'de> serde::Deserialize<'de> for Platform {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
let s = String::deserialize(deserializer)?;
FromStr::from_str(&s).map_err(serde::de::Error::custom)
}
}
impl FromStr for Platform {
type Err = ParseError;
fn from_str(s: &str) -> Result<Platform, ParseError> {
if s.starts_with("cfg(") && s.ends_with(')') {
let s = &s[4..s.len() - 1];
s.parse().map(Platform::Cfg)
} else {
Platform::validate_named_platform(s)?;
Ok(Platform::Name(s.to_string()))
}
}
}
impl fmt::Display for Platform {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
Platform::Name(ref n) => n.fmt(f),
Platform::Cfg(ref e) => write!(f, "cfg({})", e),
}
}
}
