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-rw-r--r--src/tools/cargo/crates/cargo-platform/src/cfg.rs319
1 files changed, 319 insertions, 0 deletions
diff --git a/src/tools/cargo/crates/cargo-platform/src/cfg.rs b/src/tools/cargo/crates/cargo-platform/src/cfg.rs
new file mode 100644
index 000000000..c3ddb69bc
--- /dev/null
+++ b/src/tools/cargo/crates/cargo-platform/src/cfg.rs
@@ -0,0 +1,319 @@
+use crate::error::{ParseError, ParseErrorKind::*};
+use std::fmt;
+use std::iter;
+use std::str::{self, FromStr};
+
+/// A cfg expression.
+#[derive(Eq, PartialEq, Hash, Ord, PartialOrd, Clone, Debug)]
+pub enum CfgExpr {
+ Not(Box<CfgExpr>),
+ All(Vec<CfgExpr>),
+ Any(Vec<CfgExpr>),
+ Value(Cfg),
+}
+
+/// A cfg value.
+#[derive(Eq, PartialEq, Hash, Ord, PartialOrd, Clone, Debug)]
+pub enum Cfg {
+ /// A named cfg value, like `unix`.
+ Name(String),
+ /// A key/value cfg pair, like `target_os = "linux"`.
+ KeyPair(String, String),
+}
+
+#[derive(PartialEq)]
+enum Token<'a> {
+ LeftParen,
+ RightParen,
+ Ident(&'a str),
+ Comma,
+ Equals,
+ String(&'a str),
+}
+
+#[derive(Clone)]
+struct Tokenizer<'a> {
+ s: iter::Peekable<str::CharIndices<'a>>,
+ orig: &'a str,
+}
+
+struct Parser<'a> {
+ t: Tokenizer<'a>,
+}
+
+impl FromStr for Cfg {
+ type Err = ParseError;
+
+ fn from_str(s: &str) -> Result<Cfg, Self::Err> {
+ let mut p = Parser::new(s);
+ let e = p.cfg()?;
+ if let Some(rest) = p.rest() {
+ return Err(ParseError::new(
+ p.t.orig,
+ UnterminatedExpression(rest.to_string()),
+ ));
+ }
+ Ok(e)
+ }
+}
+
+impl fmt::Display for Cfg {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match *self {
+ Cfg::Name(ref s) => s.fmt(f),
+ Cfg::KeyPair(ref k, ref v) => write!(f, "{} = \"{}\"", k, v),
+ }
+ }
+}
+
+impl CfgExpr {
+ /// Utility function to check if the key, "cfg(..)" matches the `target_cfg`
+ pub fn matches_key(key: &str, target_cfg: &[Cfg]) -> bool {
+ if key.starts_with("cfg(") && key.ends_with(')') {
+ let cfg = &key[4..key.len() - 1];
+
+ CfgExpr::from_str(cfg)
+ .ok()
+ .map(|ce| ce.matches(target_cfg))
+ .unwrap_or(false)
+ } else {
+ false
+ }
+ }
+
+ pub fn matches(&self, cfg: &[Cfg]) -> bool {
+ match *self {
+ CfgExpr::Not(ref e) => !e.matches(cfg),
+ CfgExpr::All(ref e) => e.iter().all(|e| e.matches(cfg)),
+ CfgExpr::Any(ref e) => e.iter().any(|e| e.matches(cfg)),
+ CfgExpr::Value(ref e) => cfg.contains(e),
+ }
+ }
+}
+
+impl FromStr for CfgExpr {
+ type Err = ParseError;
+
+ fn from_str(s: &str) -> Result<CfgExpr, Self::Err> {
+ let mut p = Parser::new(s);
+ let e = p.expr()?;
+ if let Some(rest) = p.rest() {
+ return Err(ParseError::new(
+ p.t.orig,
+ UnterminatedExpression(rest.to_string()),
+ ));
+ }
+ Ok(e)
+ }
+}
+
+impl fmt::Display for CfgExpr {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match *self {
+ CfgExpr::Not(ref e) => write!(f, "not({})", e),
+ CfgExpr::All(ref e) => write!(f, "all({})", CommaSep(e)),
+ CfgExpr::Any(ref e) => write!(f, "any({})", CommaSep(e)),
+ CfgExpr::Value(ref e) => write!(f, "{}", e),
+ }
+ }
+}
+
+struct CommaSep<'a, T>(&'a [T]);
+
+impl<'a, T: fmt::Display> fmt::Display for CommaSep<'a, T> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ for (i, v) in self.0.iter().enumerate() {
+ if i > 0 {
+ write!(f, ", ")?;
+ }
+ write!(f, "{}", v)?;
+ }
+ Ok(())
+ }
+}
+
+impl<'a> Parser<'a> {
+ fn new(s: &'a str) -> Parser<'a> {
+ Parser {
+ t: Tokenizer {
+ s: s.char_indices().peekable(),
+ orig: s,
+ },
+ }
+ }
+
+ fn expr(&mut self) -> Result<CfgExpr, ParseError> {
+ match self.peek() {
+ Some(Ok(Token::Ident(op @ "all"))) | Some(Ok(Token::Ident(op @ "any"))) => {
+ self.t.next();
+ let mut e = Vec::new();
+ self.eat(&Token::LeftParen)?;
+ while !self.r#try(&Token::RightParen) {
+ e.push(self.expr()?);
+ if !self.r#try(&Token::Comma) {
+ self.eat(&Token::RightParen)?;
+ break;
+ }
+ }
+ if op == "all" {
+ Ok(CfgExpr::All(e))
+ } else {
+ Ok(CfgExpr::Any(e))
+ }
+ }
+ Some(Ok(Token::Ident("not"))) => {
+ self.t.next();
+ self.eat(&Token::LeftParen)?;
+ let e = self.expr()?;
+ self.eat(&Token::RightParen)?;
+ Ok(CfgExpr::Not(Box::new(e)))
+ }
+ Some(Ok(..)) => self.cfg().map(CfgExpr::Value),
+ Some(Err(..)) => Err(self.t.next().unwrap().err().unwrap()),
+ None => Err(ParseError::new(
+ self.t.orig,
+ IncompleteExpr("start of a cfg expression"),
+ )),
+ }
+ }
+
+ fn cfg(&mut self) -> Result<Cfg, ParseError> {
+ match self.t.next() {
+ Some(Ok(Token::Ident(name))) => {
+ let e = if self.r#try(&Token::Equals) {
+ let val = match self.t.next() {
+ Some(Ok(Token::String(s))) => s,
+ Some(Ok(t)) => {
+ return Err(ParseError::new(
+ self.t.orig,
+ UnexpectedToken {
+ expected: "a string",
+ found: t.classify(),
+ },
+ ))
+ }
+ Some(Err(e)) => return Err(e),
+ None => {
+ return Err(ParseError::new(self.t.orig, IncompleteExpr("a string")))
+ }
+ };
+ Cfg::KeyPair(name.to_string(), val.to_string())
+ } else {
+ Cfg::Name(name.to_string())
+ };
+ Ok(e)
+ }
+ Some(Ok(t)) => Err(ParseError::new(
+ self.t.orig,
+ UnexpectedToken {
+ expected: "identifier",
+ found: t.classify(),
+ },
+ )),
+ Some(Err(e)) => Err(e),
+ None => Err(ParseError::new(self.t.orig, IncompleteExpr("identifier"))),
+ }
+ }
+
+ fn peek(&mut self) -> Option<Result<Token<'a>, ParseError>> {
+ self.t.clone().next()
+ }
+
+ fn r#try(&mut self, token: &Token<'a>) -> bool {
+ match self.peek() {
+ Some(Ok(ref t)) if token == t => {}
+ _ => return false,
+ }
+ self.t.next();
+ true
+ }
+
+ fn eat(&mut self, token: &Token<'a>) -> Result<(), ParseError> {
+ match self.t.next() {
+ Some(Ok(ref t)) if token == t => Ok(()),
+ Some(Ok(t)) => Err(ParseError::new(
+ self.t.orig,
+ UnexpectedToken {
+ expected: token.classify(),
+ found: t.classify(),
+ },
+ )),
+ Some(Err(e)) => Err(e),
+ None => Err(ParseError::new(
+ self.t.orig,
+ IncompleteExpr(token.classify()),
+ )),
+ }
+ }
+
+ /// Returns the rest of the input from the current location.
+ fn rest(&self) -> Option<&str> {
+ let mut s = self.t.s.clone();
+ loop {
+ match s.next() {
+ Some((_, ' ')) => {}
+ Some((start, _ch)) => return Some(&self.t.orig[start..]),
+ None => return None,
+ }
+ }
+ }
+}
+
+impl<'a> Iterator for Tokenizer<'a> {
+ type Item = Result<Token<'a>, ParseError>;
+
+ fn next(&mut self) -> Option<Result<Token<'a>, ParseError>> {
+ loop {
+ match self.s.next() {
+ Some((_, ' ')) => {}
+ Some((_, '(')) => return Some(Ok(Token::LeftParen)),
+ Some((_, ')')) => return Some(Ok(Token::RightParen)),
+ Some((_, ',')) => return Some(Ok(Token::Comma)),
+ Some((_, '=')) => return Some(Ok(Token::Equals)),
+ Some((start, '"')) => {
+ while let Some((end, ch)) = self.s.next() {
+ if ch == '"' {
+ return Some(Ok(Token::String(&self.orig[start + 1..end])));
+ }
+ }
+ return Some(Err(ParseError::new(self.orig, UnterminatedString)));
+ }
+ Some((start, ch)) if is_ident_start(ch) => {
+ while let Some(&(end, ch)) = self.s.peek() {
+ if !is_ident_rest(ch) {
+ return Some(Ok(Token::Ident(&self.orig[start..end])));
+ } else {
+ self.s.next();
+ }
+ }
+ return Some(Ok(Token::Ident(&self.orig[start..])));
+ }
+ Some((_, ch)) => {
+ return Some(Err(ParseError::new(self.orig, UnexpectedChar(ch))));
+ }
+ None => return None,
+ }
+ }
+ }
+}
+
+fn is_ident_start(ch: char) -> bool {
+ ch == '_' || ch.is_ascii_alphabetic()
+}
+
+fn is_ident_rest(ch: char) -> bool {
+ is_ident_start(ch) || ch.is_ascii_digit()
+}
+
+impl<'a> Token<'a> {
+ fn classify(&self) -> &'static str {
+ match *self {
+ Token::LeftParen => "`(`",
+ Token::RightParen => "`)`",
+ Token::Ident(..) => "an identifier",
+ Token::Comma => "`,`",
+ Token::Equals => "`=`",
+ Token::String(..) => "a string",
+ }
+ }
+}
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