use syntax::ast;
use syntax::codemap::BytePos;
use syntax::parse::new_parser_from_tts;
use syntax::parse::parser::Parser;
use syntax::parse::token::Token;
use syntax::symbol;
use syntax::tokenstream::TokenStream;
use syntax::util::ThinVec;
use codemap::SpanUtils;
use comment::{contains_comment, FindUncommented};
use expr::{rewrite_array, rewrite_call_inner};
use rewrite::{Rewrite, RewriteContext};
use shape::{Indent, Shape};
use utils::mk_sp;
const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
#[derive(Clone, Copy, PartialEq, Eq)]
enum MacroStyle {
Parens,
Brackets,
Braces,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum MacroPosition {
Item,
Statement,
Expression,
}
impl MacroStyle {
fn opener(&self) -> &'static str {
match *self {
MacroStyle::Parens => "(",
MacroStyle::Brackets => "[",
MacroStyle::Braces => "{",
}
}
}
pub enum MacroArg {
Expr(ast::Expr),
Ty(ast::Ty),
Pat(ast::Pat),
}
impl Rewrite for MacroArg {
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
match *self {
MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
}
}
}
fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
macro_rules! parse_macro_arg {
($target:tt, $macro_arg:ident, $parser:ident) => {
let mut cloned_parser = (*parser).clone();
match cloned_parser.$parser() {
Ok($target) => {
if parser.sess.span_diagnostic.has_errors() {
parser.sess.span_diagnostic.reset_err_count();
} else {
*parser = cloned_parser;
return Some(MacroArg::$macro_arg((*$target).clone()));
}
}
Err(mut e) => {
e.cancel();
parser.sess.span_diagnostic.reset_err_count();
}
}
}
}
parse_macro_arg!(expr, Expr, parse_expr);
parse_macro_arg!(ty, Ty, parse_ty);
parse_macro_arg!(pat, Pat, parse_pat);
None
}
pub fn rewrite_macro(
mac: &ast::Mac,
extra_ident: Option<ast::Ident>,
context: &RewriteContext,
shape: Shape,
position: MacroPosition,
) -> Option<String> {
let context = &mut context.clone();
context.inside_macro = true;
if context.config.use_try_shorthand() {
if let Some(expr) = convert_try_mac(mac, context) {
return expr.rewrite(context, shape);
}
}
let original_style = macro_style(mac, context);
let macro_name = match extra_ident {
None => format!("{}!", mac.node.path),
Some(ident) => if ident == symbol::keywords::Invalid.ident() {
format!("{}!", mac.node.path)
} else {
format!("{}! {}", mac.node.path, ident)
},
};
let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
MacroStyle::Brackets
} else {
original_style
};
let ts: TokenStream = mac.node.stream();
if ts.is_empty() && !contains_comment(&context.snippet(mac.span)) {
return match style {
MacroStyle::Parens if position == MacroPosition::Item => {
Some(format!("{}();", macro_name))
}
MacroStyle::Parens => Some(format!("{}()", macro_name)),
MacroStyle::Brackets => Some(format!("{}[]", macro_name)),
MacroStyle::Braces => Some(format!("{}{{}}", macro_name)),
};
}
let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
let mut arg_vec = Vec::new();
let mut vec_with_semi = false;
let mut trailing_comma = false;
if MacroStyle::Braces != style {
loop {
match parse_macro_arg(&mut parser) {
Some(arg) => arg_vec.push(arg),
None => return Some(context.snippet(mac.span)),
}
match parser.token {
Token::Eof => break,
Token::Comma => (),
Token::Semi => {
if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
parser.bump();
if parser.token != Token::Eof {
match parse_macro_arg(&mut parser) {
Some(arg) => {
arg_vec.push(arg);
parser.bump();
if parser.token == Token::Eof && arg_vec.len() == 2 {
vec_with_semi = true;
break;
}
}
None => return Some(context.snippet(mac.span)),
}
}
}
return Some(context.snippet(mac.span));
}
_ => return Some(context.snippet(mac.span)),
}
parser.bump();
if parser.token == Token::Eof {
trailing_comma = true;
break;
}
}
}
match style {
MacroStyle::Parens => {
rewrite_call_inner(
context,
¯o_name,
&arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..],
mac.span,
shape,
context.config.fn_call_width(),
trailing_comma,
).map(|rw| match position {
MacroPosition::Item => format!("{};", rw),
_ => rw,
})
}
MacroStyle::Brackets => {
let mac_shape = shape.offset_left(macro_name.len())?;
if vec_with_semi {
let (lbr, rbr) = if context.config.spaces_within_square_brackets() {
("[ ", " ]")
} else {
("[", "]")
};
let total_overhead = lbr.len() + rbr.len() + 6;
let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
let lhs = arg_vec[0].rewrite(context, nested_shape)?;
let rhs = arg_vec[1].rewrite(context, nested_shape)?;
if !lhs.contains('\n') && !rhs.contains('\n')
&& lhs.len() + rhs.len() + total_overhead <= shape.width
{
Some(format!("{}{}{}; {}{}", macro_name, lbr, lhs, rhs, rbr))
} else {
Some(format!(
"{}{}\n{}{};\n{}{}\n{}{}",
macro_name,
lbr,
nested_shape.indent.to_string(context.config),
lhs,
nested_shape.indent.to_string(context.config),
rhs,
shape.indent.to_string(context.config),
rbr
))
}
} else {
if FORCED_BRACKET_MACROS.contains(¯o_name.as_str()) {
context.inside_macro = false;
trailing_comma = false;
}
let expr_vec: Vec<_> = arg_vec
.iter()
.filter_map(|e| match *e {
MacroArg::Expr(ref e) => Some(e.clone()),
_ => None,
})
.collect();
if expr_vec.len() != arg_vec.len() {
return Some(context.snippet(mac.span));
}
let sp = mk_sp(
context
.codemap
.span_after(mac.span, original_style.opener()),
mac.span.hi() - BytePos(1),
);
let rewrite =
rewrite_array(expr_vec.iter(), sp, context, mac_shape, trailing_comma)?;
Some(format!("{}{}", macro_name, rewrite))
}
}
MacroStyle::Braces => {
indent_macro_snippet(context, &context.snippet(mac.span), shape.indent)
}
}
}
pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
if &format!("{}", mac.node.path)[..] == "try" {
let ts: TokenStream = mac.node.tts.clone().into();
let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
Some(ast::Expr {
id: ast::NodeId::new(0), node: ast::ExprKind::Try(parser.parse_expr().ok()?),
span: mac.span, attrs: ThinVec::new(),
})
} else {
None
}
}
fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> MacroStyle {
let snippet = context.snippet(mac.span);
let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
if paren_pos < bracket_pos && paren_pos < brace_pos {
MacroStyle::Parens
} else if bracket_pos < brace_pos {
MacroStyle::Brackets
} else {
MacroStyle::Braces
}
}
fn indent_macro_snippet(
context: &RewriteContext,
macro_str: &str,
indent: Indent,
) -> Option<String> {
let mut lines = macro_str.lines();
let first_line = lines.next().map(|s| s.trim_right())?;
let mut trimmed_lines = Vec::with_capacity(16);
let min_prefix_space_width = lines
.filter_map(|line| {
let prefix_space_width = if is_empty_line(line) {
None
} else {
Some(get_prefix_space_width(context, line))
};
trimmed_lines.push((line.trim(), prefix_space_width));
prefix_space_width
})
.min()?;
Some(
String::from(first_line) + "\n"
+ &trimmed_lines
.iter()
.map(|&(line, prefix_space_width)| match prefix_space_width {
Some(original_indent_width) => {
let new_indent_width = indent.width()
+ original_indent_width
.checked_sub(min_prefix_space_width)
.unwrap_or(0);
let new_indent = Indent::from_width(context.config, new_indent_width);
format!("{}{}", new_indent.to_string(context.config), line.trim())
}
None => String::new(),
})
.collect::<Vec<_>>()
.join("\n"),
)
}
fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
let mut width = 0;
for c in s.chars() {
match c {
' ' => width += 1,
'\t' => width += context.config.tab_spaces(),
_ => return width,
}
}
width
}
fn is_empty_line(s: &str) -> bool {
s.is_empty() || s.chars().all(char::is_whitespace)
}