use std::str::{self, FromStr};
use std::iter;
use std::fmt;
use util::{CargoError, CargoResult, human};
#[derive(Clone, PartialEq, Debug)]
pub enum Cfg {
Name(String),
KeyPair(String, String),
}
#[derive(Clone, PartialEq, Debug)]
pub enum CfgExpr {
Not(Box<CfgExpr>),
All(Vec<CfgExpr>),
Any(Vec<CfgExpr>),
Value(Cfg),
}
#[derive(PartialEq)]
enum Token<'a> {
LeftParen,
RightParen,
Ident(&'a str),
Comma,
Equals,
String(&'a str),
}
struct Tokenizer<'a> {
s: iter::Peekable<str::CharIndices<'a>>,
orig: &'a str,
}
struct Parser<'a> {
t: iter::Peekable<Tokenizer<'a>>,
}
impl FromStr for Cfg {
type Err = Box<CargoError>;
fn from_str(s: &str) -> CargoResult<Cfg> {
let mut p = Parser::new(s);
let e = try!(p.cfg());
if p.t.next().is_some() {
bail!("malformed cfg value or key/value pair")
}
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 {
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 = Box<CargoError>;
fn from_str(s: &str) -> CargoResult<CfgExpr> {
let mut p = Parser::new(s);
let e = try!(p.expr());
if p.t.next().is_some() {
bail!("can only have one cfg-expression, consider using all() or \
any() explicitly")
}
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>(&'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 {
try!(write!(f, ", "));
}
try!(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,
}.peekable(),
}
}
fn expr(&mut self) -> CargoResult<CfgExpr> {
match self.t.peek() {
Some(&Ok(Token::Ident(op @ "all"))) |
Some(&Ok(Token::Ident(op @ "any"))) => {
self.t.next();
let mut e = Vec::new();
try!(self.eat(Token::LeftParen));
while !self.try(Token::RightParen) {
e.push(try!(self.expr()));
if !self.try(Token::Comma) {
try!(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();
try!(self.eat(Token::LeftParen));
let e = try!(self.expr());
try!(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 => bail!("expected start of a cfg expression, \
found nothing"),
}
}
fn cfg(&mut self) -> CargoResult<Cfg> {
match self.t.next() {
Some(Ok(Token::Ident(name))) => {
let e = if self.try(Token::Equals) {
let val = match self.t.next() {
Some(Ok(Token::String(s))) => s,
Some(Ok(t)) => bail!("expected a string, found {}",
t.classify()),
Some(Err(e)) => return Err(e),
None => bail!("expected a string, found nothing"),
};
Cfg::KeyPair(name.to_string(), val.to_string())
} else {
Cfg::Name(name.to_string())
};
Ok(e)
}
Some(Ok(t)) => bail!("expected identifier, found {}", t.classify()),
Some(Err(e)) => Err(e),
None => bail!("expected identifier, found nothing"),
}
}
fn try(&mut self, token: Token<'a>) -> bool {
match self.t.peek() {
Some(&Ok(ref t)) if token == *t => {}
_ => return false,
}
self.t.next();
true
}
fn eat(&mut self, token: Token<'a>) -> CargoResult<()> {
match self.t.next() {
Some(Ok(ref t)) if token == *t => Ok(()),
Some(Ok(t)) => bail!("expected {}, found {}", token.classify(),
t.classify()),
Some(Err(e)) => Err(e),
None => bail!("expected {}, but cfg expr ended", token.classify()),
}
}
}
impl<'a> Iterator for Tokenizer<'a> {
type Item = CargoResult<Token<'a>>;
fn next(&mut self) -> Option<CargoResult<Token<'a>>> {
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(human(format!("unterminated string in cfg"))))
}
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(human(format!("unexpected character in \
cfg `{}`, expected parens, \
a comma, an identifier, or \
a string", ch))))
}
None => return None
}
}
}
}
fn is_ident_start(ch: char) -> bool {
ch == '_' || ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z')
}
fn is_ident_rest(ch: char) -> bool {
is_ident_start(ch) || ('0' <= ch && ch <= '9')
}
impl<'a> Token<'a> {
fn classify(&self) -> &str {
match *self {
Token::LeftParen => "`(`",
Token::RightParen => "`)`",
Token::Ident(..) => "an identifier",
Token::Comma => "`,`",
Token::Equals => "`=`",
Token::String(..) => "a string",
}
}
}