1 files changed, 163 insertions, 0 deletions
diff --git a/vendor/rustversion/src/expr.rs b/vendor/rustversion/src/expr.rs
new file mode 100644
index 000000000..45ed7d215
--- /dev/null
+++ b/vendor/rustversion/src/expr.rs
@@ -0,0 +1,163 @@
+use crate::bound::{self, Bound};
+use crate::date::{self, Date};
+use crate::error::{Error, Result};
+use crate::iter::{self, Iter};
+use crate::release::{self, Release};
+use crate::token;
+use crate::version::{Channel, Version};
+use proc_macro::{Ident, Span, TokenTree};
+
+pub enum Expr {
+    Stable,
+    Beta,
+    Nightly,
+    Date(Date),
+    Since(Bound),
+    Before(Bound),
+    Release(Release),
+    Not(Box<Expr>),
+    Any(Vec<Expr>),
+    All(Vec<Expr>),
+}
+
+impl Expr {
+    pub fn eval(&self, rustc: Version) -> bool {
+        use self::Expr::*;
+
+        match self {
+            Stable => rustc.channel == Channel::Stable,
+            Beta => rustc.channel == Channel::Beta,
+            Nightly => match rustc.channel {
+                Channel::Nightly(_) | Channel::Dev => true,
+                Channel::Stable | Channel::Beta => false,
+            },
+            Date(date) => match rustc.channel {
+                Channel::Nightly(rustc) => rustc == *date,
+                Channel::Stable | Channel::Beta | Channel::Dev => false,
+            },
+            Since(bound) => rustc >= *bound,
+            Before(bound) => rustc < *bound,
+            Release(release) => {
+                rustc.channel == Channel::Stable
+                    && rustc.minor == release.minor
+                    && release.patch.map_or(true, |patch| rustc.patch == patch)
+            }
+            Not(expr) => !expr.eval(rustc),
+            Any(exprs) => exprs.iter().any(|e| e.eval(rustc)),
+            All(exprs) => exprs.iter().all(|e| e.eval(rustc)),
+        }
+    }
+}
+
+pub fn parse(iter: Iter) -> Result<Expr> {
+    match &iter.next() {
+        Some(TokenTree::Ident(i)) if i.to_string() == "stable" => parse_stable(iter),
+        Some(TokenTree::Ident(i)) if i.to_string() == "beta" => Ok(Expr::Beta),
+        Some(TokenTree::Ident(i)) if i.to_string() == "nightly" => parse_nightly(iter),
+        Some(TokenTree::Ident(i)) if i.to_string() == "since" => parse_since(i, iter),
+        Some(TokenTree::Ident(i)) if i.to_string() == "before" => parse_before(i, iter),
+        Some(TokenTree::Ident(i)) if i.to_string() == "not" => parse_not(i, iter),
+        Some(TokenTree::Ident(i)) if i.to_string() == "any" => parse_any(i, iter),
+        Some(TokenTree::Ident(i)) if i.to_string() == "all" => parse_all(i, iter),
+        unexpected => {
+            let span = unexpected
+                .as_ref()
+                .map_or_else(Span::call_site, TokenTree::span);
+            Err(Error::new(span, "expected one of `stable`, `beta`, `nightly`, `since`, `before`, `not`, `any`, `all`"))
+        }
+    }
+}
+
+fn parse_nightly(iter: Iter) -> Result<Expr> {
+    let paren = match token::parse_optional_paren(iter) {
+        Some(group) => group,
+        None => return Ok(Expr::Nightly),
+    };
+
+    let ref mut inner = iter::new(paren.stream());
+    let date = date::parse(paren, inner)?;
+    token::parse_optional_punct(inner, ',');
+    token::parse_end(inner)?;
+
+    Ok(Expr::Date(date))
+}
+
+fn parse_stable(iter: Iter) -> Result<Expr> {
+    let paren = match token::parse_optional_paren(iter) {
+        Some(group) => group,
+        None => return Ok(Expr::Stable),
+    };
+
+    let ref mut inner = iter::new(paren.stream());
+    let release = release::parse(paren, inner)?;
+    token::parse_optional_punct(inner, ',');
+    token::parse_end(inner)?;
+
+    Ok(Expr::Release(release))
+}
+
+fn parse_since(introducer: &Ident, iter: Iter) -> Result<Expr> {
+    let paren = token::parse_paren(introducer, iter)?;
+
+    let ref mut inner = iter::new(paren.stream());
+    let bound = bound::parse(paren, inner)?;
+    token::parse_optional_punct(inner, ',');
+    token::parse_end(inner)?;
+
+    Ok(Expr::Since(bound))
+}
+
+fn parse_before(introducer: &Ident, iter: Iter) -> Result<Expr> {
+    let paren = token::parse_paren(introducer, iter)?;
+
+    let ref mut inner = iter::new(paren.stream());
+    let bound = bound::parse(paren, inner)?;
+    token::parse_optional_punct(inner, ',');
+    token::parse_end(inner)?;
+
+    Ok(Expr::Before(bound))
+}
+
+fn parse_not(introducer: &Ident, iter: Iter) -> Result<Expr> {
+    let paren = token::parse_paren(introducer, iter)?;
+
+    let ref mut inner = iter::new(paren.stream());
+    let expr = self::parse(inner)?;
+    token::parse_optional_punct(inner, ',');
+    token::parse_end(inner)?;
+
+    Ok(Expr::Not(Box::new(expr)))
+}
+
+fn parse_any(introducer: &Ident, iter: Iter) -> Result<Expr> {
+    let paren = token::parse_paren(introducer, iter)?;
+
+    let ref mut inner = iter::new(paren.stream());
+    let exprs = parse_comma_separated(inner)?;
+
+    Ok(Expr::Any(exprs.into_iter().collect()))
+}
+
+fn parse_all(introducer: &Ident, iter: Iter) -> Result<Expr> {
+    let paren = token::parse_paren(introducer, iter)?;
+
+    let ref mut inner = iter::new(paren.stream());
+    let exprs = parse_comma_separated(inner)?;
+
+    Ok(Expr::All(exprs.into_iter().collect()))
+}
+
+fn parse_comma_separated(iter: Iter) -> Result<Vec<Expr>> {
+    let mut exprs = Vec::new();
+
+    while iter.peek().is_some() {
+        let expr = self::parse(iter)?;
+        exprs.push(expr);
+        if iter.peek().is_none() {
+            break;
+        }
+        token::parse_punct(iter, ',')?;
+    }
+
+    Ok(exprs)
+}