diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs index e759baa0458..dfa83ba9959 100644 --- a/src/librustdoc/clean/mod.rs +++ b/src/librustdoc/clean/mod.rs @@ -5,6 +5,7 @@ mod blanket_impl; crate mod cfg; crate mod inline; +mod render_macro_matchers; mod simplify; crate mod types; crate mod utils; diff --git a/src/librustdoc/clean/render_macro_matchers.rs b/src/librustdoc/clean/render_macro_matchers.rs new file mode 100644 index 00000000000..14990c2e9e6 --- /dev/null +++ b/src/librustdoc/clean/render_macro_matchers.rs @@ -0,0 +1,191 @@ +use rustc_ast::token::{self, BinOpToken, DelimToken}; +use rustc_ast::tokenstream::{TokenStream, TokenTree}; +use rustc_ast_pretty::pprust::state::State as Printer; +use rustc_ast_pretty::pprust::PrintState; +use rustc_middle::ty::TyCtxt; +use rustc_session::parse::ParseSess; +use rustc_span::source_map::FilePathMapping; +use rustc_span::symbol::Symbol; + +/// Render a macro matcher in a format suitable for displaying to the user +/// as part of an item declaration. +pub(super) fn render_macro_matcher(tcx: TyCtxt<'_>, matcher: &TokenTree) -> String { + if let Some(snippet) = snippet_equal_to_token(tcx, matcher) { + // If the original source code is known, we display the matcher exactly + // as present in the source code. + return snippet; + } + + // If the matcher is macro-generated or some other reason the source code + // snippet is not available, we attempt to nicely render the token tree. + let mut printer = Printer::new(); + + // If the inner ibox fits on one line, we get: + // + // macro_rules! macroname { + // (the matcher) => {...}; + // } + // + // If the inner ibox gets wrapped, the cbox will break and get indented: + // + // macro_rules! macroname { + // ( + // the matcher ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~! + // ) => {...}; + // } + printer.cbox(8); + printer.word("("); + printer.zerobreak(); + printer.ibox(0); + match matcher { + TokenTree::Delimited(_span, _delim, tts) => print_tts(&mut printer, tts), + // Matcher which is not a Delimited is unexpected and should've failed + // to compile, but we render whatever it is wrapped in parens. + TokenTree::Token(_) => print_tt(&mut printer, matcher), + } + printer.end(); + printer.break_offset_if_not_bol(0, -4); + printer.word(")"); + printer.end(); + printer.s.eof() +} + +/// Find the source snippet for this token's Span, reparse it, and return the +/// snippet if the reparsed TokenTree matches the argument TokenTree. +fn snippet_equal_to_token(tcx: TyCtxt<'_>, matcher: &TokenTree) -> Option { + // Find what rustc thinks is the source snippet. + // This may not actually be anything meaningful if this matcher was itself + // generated by a macro. + let source_map = tcx.sess.source_map(); + let span = matcher.span(); + let snippet = source_map.span_to_snippet(span).ok()?; + + // Create a Parser. + let sess = ParseSess::new(FilePathMapping::empty()); + let file_name = source_map.span_to_filename(span); + let mut parser = + match rustc_parse::maybe_new_parser_from_source_str(&sess, file_name, snippet.clone()) { + Ok(parser) => parser, + Err(diagnostics) => { + for mut diagnostic in diagnostics { + diagnostic.cancel(); + } + return None; + } + }; + + // Reparse a single token tree. + let mut reparsed_trees = match parser.parse_all_token_trees() { + Ok(reparsed_trees) => reparsed_trees, + Err(mut diagnostic) => { + diagnostic.cancel(); + return None; + } + }; + if reparsed_trees.len() != 1 { + return None; + } + let reparsed_tree = reparsed_trees.pop().unwrap(); + + // Compare against the original tree. + if reparsed_tree.eq_unspanned(matcher) { Some(snippet) } else { None } +} + +fn print_tt(printer: &mut Printer<'_>, tt: &TokenTree) { + match tt { + TokenTree::Token(token) => { + let token_str = printer.token_to_string(token); + printer.word(token_str); + if let token::DocComment(..) = token.kind { + printer.hardbreak() + } + } + TokenTree::Delimited(_span, delim, tts) => { + let open_delim = printer.token_kind_to_string(&token::OpenDelim(*delim)); + printer.word(open_delim); + if !tts.is_empty() { + if *delim == DelimToken::Brace { + printer.space(); + } + print_tts(printer, tts); + if *delim == DelimToken::Brace { + printer.space(); + } + } + let close_delim = printer.token_kind_to_string(&token::CloseDelim(*delim)); + printer.word(close_delim); + } + } +} + +fn print_tts(printer: &mut Printer<'_>, tts: &TokenStream) { + #[derive(Copy, Clone, PartialEq)] + enum State { + Start, + Dollar, + DollarIdent, + DollarIdentColon, + DollarParen, + DollarParenSep, + Pound, + PoundBang, + Ident, + Other, + } + + use State::*; + + let mut state = Start; + for tt in tts.trees() { + let (needs_space, next_state) = match &tt { + TokenTree::Token(tt) => match (state, &tt.kind) { + (Dollar, token::Ident(..)) => (false, DollarIdent), + (DollarIdent, token::Colon) => (false, DollarIdentColon), + (DollarIdentColon, token::Ident(..)) => (false, Other), + ( + DollarParen, + token::BinOp(BinOpToken::Plus | BinOpToken::Star) | token::Question, + ) => (false, Other), + (DollarParen, _) => (false, DollarParenSep), + (DollarParenSep, token::BinOp(BinOpToken::Plus | BinOpToken::Star)) => { + (false, Other) + } + (Pound, token::Not) => (false, PoundBang), + (_, token::Ident(symbol, /* is_raw */ false)) + if !usually_needs_space_between_keyword_and_open_delim(*symbol) => + { + (true, Ident) + } + (_, token::Comma | token::Semi) => (false, Other), + (_, token::Dollar) => (true, Dollar), + (_, token::Pound) => (true, Pound), + (_, _) => (true, Other), + }, + TokenTree::Delimited(_, delim, _) => match (state, delim) { + (Dollar, DelimToken::Paren) => (false, DollarParen), + (Pound | PoundBang, DelimToken::Bracket) => (false, Other), + (Ident, DelimToken::Paren | DelimToken::Bracket) => (false, Other), + (_, _) => (true, Other), + }, + }; + if state != Start && needs_space { + printer.space(); + } + print_tt(printer, &tt); + state = next_state; + } +} + +// This rough subset of keywords is listed here to distinguish tokens resembling +// `f(0)` (no space between ident and paren) from tokens resembling `if let (0, +// 0) = x` (space between ident and paren). +fn usually_needs_space_between_keyword_and_open_delim(symbol: Symbol) -> bool { + match symbol.as_str() { + "as" | "box" | "break" | "const" | "continue" | "crate" | "else" | "enum" | "extern" + | "for" | "if" | "impl" | "in" | "let" | "loop" | "macro" | "match" | "mod" | "move" + | "mut" | "ref" | "return" | "static" | "struct" | "trait" | "type" | "unsafe" | "use" + | "where" | "while" | "yield" => true, + _ => false, + } +} diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs index a88e11b667a..dabf1e878c9 100644 --- a/src/librustdoc/clean/utils.rs +++ b/src/librustdoc/clean/utils.rs @@ -1,5 +1,6 @@ use crate::clean::auto_trait::AutoTraitFinder; use crate::clean::blanket_impl::BlanketImplFinder; +use crate::clean::render_macro_matchers::render_macro_matcher; use crate::clean::{ inline, Clean, Crate, ExternalCrate, Generic, GenericArg, GenericArgs, ImportSource, Item, ItemKind, Lifetime, Path, PathSegment, Primitive, PrimitiveType, Type, TypeBinding, Visibility, @@ -9,10 +10,7 @@ use crate::visit_lib::LibEmbargoVisitor; use rustc_ast as ast; -use rustc_ast::token::{self, BinOpToken, DelimToken}; -use rustc_ast::tokenstream::{TokenStream, TokenTree}; -use rustc_ast_pretty::pprust::state::State as Printer; -use rustc_ast_pretty::pprust::PrintState; +use rustc_ast::tokenstream::TokenTree; use rustc_data_structures::thin_vec::ThinVec; use rustc_hir as hir; use rustc_hir::def::{DefKind, Res}; @@ -20,8 +18,6 @@ use rustc_middle::mir::interpret::ConstValue; use rustc_middle::ty::subst::{GenericArgKind, SubstsRef}; use rustc_middle::ty::{self, DefIdTree, TyCtxt}; -use rustc_session::parse::ParseSess; -use rustc_span::source_map::FilePathMapping; use rustc_span::symbol::{kw, sym, Symbol}; use std::fmt::Write as _; use std::mem; @@ -503,189 +499,6 @@ pub(super) fn render_macro_arms<'a>( out } -/// Render a macro matcher in a format suitable for displaying to the user -/// as part of an item declaration. -pub(super) fn render_macro_matcher(tcx: TyCtxt<'_>, matcher: &TokenTree) -> String { - if let Some(snippet) = snippet_equal_to_token(tcx, matcher) { - // If the original source code is known, we display the matcher exactly - // as present in the source code. - return snippet; - } - - // If the matcher is macro-generated or some other reason the source code - // snippet is not available, we attempt to nicely render the token tree. - let mut printer = Printer::new(); - - // If the inner ibox fits on one line, we get: - // - // macro_rules! macroname { - // (the matcher) => {...}; - // } - // - // If the inner ibox gets wrapped, the cbox will break and get indented: - // - // macro_rules! macroname { - // ( - // the matcher ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~! - // ) => {...}; - // } - printer.cbox(8); - printer.word("("); - printer.zerobreak(); - printer.ibox(0); - match matcher { - TokenTree::Delimited(_span, _delim, tts) => print_tts(&mut printer, tts), - // Matcher which is not a Delimited is unexpected and should've failed - // to compile, but we render whatever it is wrapped in parens. - TokenTree::Token(_) => print_tt(&mut printer, matcher), - } - printer.end(); - printer.break_offset_if_not_bol(0, -4); - printer.word(")"); - printer.end(); - printer.s.eof() -} - -/// Find the source snippet for this token's Span, reparse it, and return the -/// snippet if the reparsed TokenTree matches the argument TokenTree. -fn snippet_equal_to_token(tcx: TyCtxt<'_>, matcher: &TokenTree) -> Option { - // Find what rustc thinks is the source snippet. - // This may not actually be anything meaningful if this matcher was itself - // generated by a macro. - let source_map = tcx.sess.source_map(); - let span = matcher.span(); - let snippet = source_map.span_to_snippet(span).ok()?; - - // Create a Parser. - let sess = ParseSess::new(FilePathMapping::empty()); - let file_name = source_map.span_to_filename(span); - let mut parser = - match rustc_parse::maybe_new_parser_from_source_str(&sess, file_name, snippet.clone()) { - Ok(parser) => parser, - Err(diagnostics) => { - for mut diagnostic in diagnostics { - diagnostic.cancel(); - } - return None; - } - }; - - // Reparse a single token tree. - let mut reparsed_trees = match parser.parse_all_token_trees() { - Ok(reparsed_trees) => reparsed_trees, - Err(mut diagnostic) => { - diagnostic.cancel(); - return None; - } - }; - if reparsed_trees.len() != 1 { - return None; - } - let reparsed_tree = reparsed_trees.pop().unwrap(); - - // Compare against the original tree. - if reparsed_tree.eq_unspanned(matcher) { Some(snippet) } else { None } -} - -fn print_tt(printer: &mut Printer<'_>, tt: &TokenTree) { - match tt { - TokenTree::Token(token) => { - let token_str = printer.token_to_string(token); - printer.word(token_str); - if let token::DocComment(..) = token.kind { - printer.hardbreak() - } - } - TokenTree::Delimited(_span, delim, tts) => { - let open_delim = printer.token_kind_to_string(&token::OpenDelim(*delim)); - printer.word(open_delim); - if !tts.is_empty() { - if *delim == DelimToken::Brace { - printer.space(); - } - print_tts(printer, tts); - if *delim == DelimToken::Brace { - printer.space(); - } - } - let close_delim = printer.token_kind_to_string(&token::CloseDelim(*delim)); - printer.word(close_delim); - } - } -} - -fn print_tts(printer: &mut Printer<'_>, tts: &TokenStream) { - #[derive(Copy, Clone, PartialEq)] - enum State { - Start, - Dollar, - DollarIdent, - DollarIdentColon, - DollarParen, - DollarParenSep, - Pound, - PoundBang, - Ident, - Other, - } - - use State::*; - - let mut state = Start; - for tt in tts.trees() { - let (needs_space, next_state) = match &tt { - TokenTree::Token(tt) => match (state, &tt.kind) { - (Dollar, token::Ident(..)) => (false, DollarIdent), - (DollarIdent, token::Colon) => (false, DollarIdentColon), - (DollarIdentColon, token::Ident(..)) => (false, Other), - ( - DollarParen, - token::BinOp(BinOpToken::Plus | BinOpToken::Star) | token::Question, - ) => (false, Other), - (DollarParen, _) => (false, DollarParenSep), - (DollarParenSep, token::BinOp(BinOpToken::Plus | BinOpToken::Star)) => { - (false, Other) - } - (Pound, token::Not) => (false, PoundBang), - (_, token::Ident(symbol, /* is_raw */ false)) - if !usually_needs_space_between_keyword_and_open_delim(*symbol) => - { - (true, Ident) - } - (_, token::Comma | token::Semi) => (false, Other), - (_, token::Dollar) => (true, Dollar), - (_, token::Pound) => (true, Pound), - (_, _) => (true, Other), - }, - TokenTree::Delimited(_, delim, _) => match (state, delim) { - (Dollar, DelimToken::Paren) => (false, DollarParen), - (Pound | PoundBang, DelimToken::Bracket) => (false, Other), - (Ident, DelimToken::Paren | DelimToken::Bracket) => (false, Other), - (_, _) => (true, Other), - }, - }; - if state != Start && needs_space { - printer.space(); - } - print_tt(printer, &tt); - state = next_state; - } -} - -// This rough subset of keywords is listed here to distinguish tokens resembling -// `f(0)` (no space between ident and paren) from tokens resembling `if let (0, -// 0) = x` (space between ident and paren). -fn usually_needs_space_between_keyword_and_open_delim(symbol: Symbol) -> bool { - match symbol.as_str() { - "as" | "box" | "break" | "const" | "continue" | "crate" | "else" | "enum" | "extern" - | "for" | "if" | "impl" | "in" | "let" | "loop" | "macro" | "match" | "mod" | "move" - | "mut" | "ref" | "return" | "static" | "struct" | "trait" | "type" | "unsafe" | "use" - | "where" | "while" | "yield" => true, - _ => false, - } -} - pub(super) fn display_macro_source( cx: &mut DocContext<'_>, name: Symbol,