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Diffstat (limited to 'vendor/miette-derive/src/fmt.rs')
-rw-r--r-- | vendor/miette-derive/src/fmt.rs | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/vendor/miette-derive/src/fmt.rs b/vendor/miette-derive/src/fmt.rs new file mode 100644 index 0000000..692c5ad --- /dev/null +++ b/vendor/miette-derive/src/fmt.rs @@ -0,0 +1,235 @@ +// NOTE: Most code in this file is taken straight from `thiserror`. +use std::collections::HashSet as Set; +use std::iter::FromIterator; + +use proc_macro2::{Delimiter, Group, TokenStream, TokenTree}; +use quote::{format_ident, quote, quote_spanned, ToTokens}; +use syn::ext::IdentExt; +use syn::parse::{ParseStream, Parser}; +use syn::{braced, bracketed, parenthesized, Ident, Index, LitStr, Member, Result, Token}; + +#[derive(Clone)] +pub struct Display { + pub fmt: LitStr, + pub args: TokenStream, + pub has_bonus_display: bool, +} + +impl ToTokens for Display { + fn to_tokens(&self, tokens: &mut TokenStream) { + let fmt = &self.fmt; + let args = &self.args; + tokens.extend(quote! { + write!(__formatter, #fmt #args) + }); + } +} + +impl Display { + // Transform `"error {var}"` to `"error {}", var`. + pub fn expand_shorthand(&mut self, members: &Set<Member>) { + let raw_args = self.args.clone(); + let mut named_args = explicit_named_args.parse2(raw_args).unwrap(); + + let span = self.fmt.span(); + let fmt = self.fmt.value(); + let mut read = fmt.as_str(); + let mut out = String::new(); + let mut args = self.args.clone(); + let mut has_bonus_display = false; + + let mut has_trailing_comma = false; + if let Some(TokenTree::Punct(punct)) = args.clone().into_iter().last() { + if punct.as_char() == ',' { + has_trailing_comma = true; + } + } + + while let Some(brace) = read.find('{') { + out += &read[..brace + 1]; + read = &read[brace + 1..]; + if read.starts_with('{') { + out.push('{'); + read = &read[1..]; + continue; + } + let next = match read.chars().next() { + Some(next) => next, + None => return, + }; + let member = match next { + '0'..='9' => { + let int = take_int(&mut read); + let member = match int.parse::<u32>() { + Ok(index) => Member::Unnamed(Index { index, span }), + Err(_) => return, + }; + if !members.contains(&member) { + out += ∫ + continue; + } + member + } + 'a'..='z' | 'A'..='Z' | '_' => { + let mut ident = take_ident(&mut read); + ident.set_span(span); + Member::Named(ident) + } + _ => continue, + }; + let local = match &member { + Member::Unnamed(index) => format_ident!("_{}", index), + Member::Named(ident) => ident.clone(), + }; + let mut formatvar = local.clone(); + if formatvar.to_string().starts_with("r#") { + formatvar = format_ident!("r_{}", formatvar); + } + if formatvar.to_string().starts_with('_') { + // Work around leading underscore being rejected by 1.40 and + // older compilers. https://github.com/rust-lang/rust/pull/66847 + formatvar = format_ident!("field_{}", formatvar); + } + out += &formatvar.to_string(); + if !named_args.insert(formatvar.clone()) { + // Already specified in the format argument list. + continue; + } + if !has_trailing_comma { + args.extend(quote_spanned!(span=> ,)); + } + args.extend(quote_spanned!(span=> #formatvar = #local)); + if read.starts_with('}') && members.contains(&member) { + has_bonus_display = true; + // args.extend(quote_spanned!(span=> .as_display())); + } + has_trailing_comma = false; + } + + out += read; + self.fmt = LitStr::new(&out, self.fmt.span()); + self.args = args; + self.has_bonus_display = has_bonus_display; + } +} + +fn explicit_named_args(input: ParseStream) -> Result<Set<Ident>> { + let mut named_args = Set::new(); + + while !input.is_empty() { + if input.peek(Token![,]) && input.peek2(Ident::peek_any) && input.peek3(Token![=]) { + input.parse::<Token![,]>()?; + let ident = input.call(Ident::parse_any)?; + input.parse::<Token![=]>()?; + named_args.insert(ident); + } else { + input.parse::<TokenTree>()?; + } + } + + Ok(named_args) +} + +fn take_int(read: &mut &str) -> String { + let mut int = String::new(); + for (i, ch) in read.char_indices() { + match ch { + '0'..='9' => int.push(ch), + _ => { + *read = &read[i..]; + break; + } + } + } + int +} + +fn take_ident(read: &mut &str) -> Ident { + let mut ident = String::new(); + let raw = read.starts_with("r#"); + if raw { + ident.push_str("r#"); + *read = &read[2..]; + } + for (i, ch) in read.char_indices() { + match ch { + 'a'..='z' | 'A'..='Z' | '0'..='9' | '_' => ident.push(ch), + _ => { + *read = &read[i..]; + break; + } + } + } + Ident::parse_any.parse_str(&ident).unwrap() +} + +pub fn parse_token_expr(input: ParseStream, mut begin_expr: bool) -> Result<TokenStream> { + let mut tokens = Vec::new(); + while !input.is_empty() { + if begin_expr && input.peek(Token![.]) { + if input.peek2(Ident) { + input.parse::<Token![.]>()?; + begin_expr = false; + continue; + } + if input.peek2(syn::LitInt) { + input.parse::<Token![.]>()?; + let int: Index = input.parse()?; + let ident = format_ident!("_{}", int.index, span = int.span); + tokens.push(TokenTree::Ident(ident)); + begin_expr = false; + continue; + } + } + + begin_expr = input.peek(Token![break]) + || input.peek(Token![continue]) + || input.peek(Token![if]) + || input.peek(Token![in]) + || input.peek(Token![match]) + || input.peek(Token![mut]) + || input.peek(Token![return]) + || input.peek(Token![while]) + || input.peek(Token![+]) + || input.peek(Token![&]) + || input.peek(Token![!]) + || input.peek(Token![^]) + || input.peek(Token![,]) + || input.peek(Token![/]) + || input.peek(Token![=]) + || input.peek(Token![>]) + || input.peek(Token![<]) + || input.peek(Token![|]) + || input.peek(Token![%]) + || input.peek(Token![;]) + || input.peek(Token![*]) + || input.peek(Token![-]); + + let token: TokenTree = if input.peek(syn::token::Paren) { + let content; + let delimiter = parenthesized!(content in input); + let nested = parse_token_expr(&content, true)?; + let mut group = Group::new(Delimiter::Parenthesis, nested); + group.set_span(delimiter.span.join()); + TokenTree::Group(group) + } else if input.peek(syn::token::Brace) { + let content; + let delimiter = braced!(content in input); + let nested = parse_token_expr(&content, true)?; + let mut group = Group::new(Delimiter::Brace, nested); + group.set_span(delimiter.span.join()); + TokenTree::Group(group) + } else if input.peek(syn::token::Bracket) { + let content; + let delimiter = bracketed!(content in input); + let nested = parse_token_expr(&content, true)?; + let mut group = Group::new(Delimiter::Bracket, nested); + group.set_span(delimiter.span.join()); + TokenTree::Group(group) + } else { + input.parse()? + }; + tokens.push(token); + } + Ok(TokenStream::from_iter(tokens)) +} |