| use syntax::ast::{self, BindingMode, FieldPat, Pat, PatKind, RangeEnd, RangeSyntax}; |
| use syntax::ptr; |
| use syntax::source_map::{self, BytePos, Span}; |
| |
| use crate::comment::FindUncommented; |
| use crate::config::lists::*; |
| use crate::expr::{can_be_overflowed_expr, rewrite_unary_prefix, wrap_struct_field}; |
| use crate::lists::{ |
| itemize_list, shape_for_tactic, struct_lit_formatting, struct_lit_shape, struct_lit_tactic, |
| write_list, |
| }; |
| use crate::macros::{rewrite_macro, MacroPosition}; |
| use crate::overflow; |
| use crate::pairs::{rewrite_pair, PairParts}; |
| use crate::rewrite::{Rewrite, RewriteContext}; |
| use crate::shape::Shape; |
| use crate::source_map::SpanUtils; |
| use crate::spanned::Spanned; |
| use crate::types::{rewrite_path, PathContext}; |
| use crate::utils::{format_mutability, mk_sp, rewrite_ident}; |
| |
| /// Returns `true` if the given pattern is "short". |
| /// A short pattern is defined by the following grammar: |
| /// |
| /// [small, ntp]: |
| /// - single token |
| /// - `&[single-line, ntp]` |
| /// |
| /// [small]: |
| /// - `[small, ntp]` |
| /// - unary tuple constructor `([small, ntp])` |
| /// - `&[small]` |
| pub(crate) fn is_short_pattern(pat: &ast::Pat, pat_str: &str) -> bool { |
| // We also require that the pattern is reasonably 'small' with its literal width. |
| pat_str.len() <= 20 && !pat_str.contains('\n') && is_short_pattern_inner(pat) |
| } |
| |
| fn is_short_pattern_inner(pat: &ast::Pat) -> bool { |
| match pat.node { |
| ast::PatKind::Wild | ast::PatKind::Lit(_) => true, |
| ast::PatKind::Ident(_, _, ref pat) => pat.is_none(), |
| ast::PatKind::Struct(..) |
| | ast::PatKind::Mac(..) |
| | ast::PatKind::Slice(..) |
| | ast::PatKind::Path(..) |
| | ast::PatKind::Range(..) => false, |
| ast::PatKind::Tuple(ref subpats, _) => subpats.len() <= 1, |
| ast::PatKind::TupleStruct(ref path, ref subpats, _) => { |
| path.segments.len() <= 1 && subpats.len() <= 1 |
| } |
| ast::PatKind::Box(ref p) | ast::PatKind::Ref(ref p, _) | ast::PatKind::Paren(ref p) => { |
| is_short_pattern_inner(&*p) |
| } |
| } |
| } |
| |
| impl Rewrite for Pat { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| match self.node { |
| PatKind::Box(ref pat) => rewrite_unary_prefix(context, "box ", &**pat, shape), |
| PatKind::Ident(binding_mode, ident, ref sub_pat) => { |
| let (prefix, mutability) = match binding_mode { |
| BindingMode::ByRef(mutability) => ("ref ", mutability), |
| BindingMode::ByValue(mutability) => ("", mutability), |
| }; |
| let mut_infix = format_mutability(mutability); |
| let id_str = rewrite_ident(context, ident); |
| let sub_pat = match *sub_pat { |
| Some(ref p) => { |
| // 3 - ` @ `. |
| let width = shape |
| .width |
| .checked_sub(prefix.len() + mut_infix.len() + id_str.len() + 3)?; |
| format!( |
| " @ {}", |
| p.rewrite(context, Shape::legacy(width, shape.indent))? |
| ) |
| } |
| None => "".to_owned(), |
| }; |
| |
| Some(format!("{}{}{}{}", prefix, mut_infix, id_str, sub_pat)) |
| } |
| PatKind::Wild => { |
| if 1 <= shape.width { |
| Some("_".to_owned()) |
| } else { |
| None |
| } |
| } |
| PatKind::Range(ref lhs, ref rhs, ref end_kind) => { |
| let infix = match end_kind.node { |
| RangeEnd::Included(RangeSyntax::DotDotDot) => "...", |
| RangeEnd::Included(RangeSyntax::DotDotEq) => "..=", |
| RangeEnd::Excluded => "..", |
| }; |
| let infix = if context.config.spaces_around_ranges() { |
| format!(" {} ", infix) |
| } else { |
| infix.to_owned() |
| }; |
| rewrite_pair( |
| &**lhs, |
| &**rhs, |
| PairParts::infix(&infix), |
| context, |
| shape, |
| SeparatorPlace::Front, |
| ) |
| } |
| PatKind::Ref(ref pat, mutability) => { |
| let prefix = format!("&{}", format_mutability(mutability)); |
| rewrite_unary_prefix(context, &prefix, &**pat, shape) |
| } |
| PatKind::Tuple(ref items, dotdot_pos) => { |
| rewrite_tuple_pat(items, dotdot_pos, None, self.span, context, shape) |
| } |
| PatKind::Path(ref q_self, ref path) => { |
| rewrite_path(context, PathContext::Expr, q_self.as_ref(), path, shape) |
| } |
| PatKind::TupleStruct(ref path, ref pat_vec, dotdot_pos) => { |
| let path_str = rewrite_path(context, PathContext::Expr, None, path, shape)?; |
| rewrite_tuple_pat( |
| pat_vec, |
| dotdot_pos, |
| Some(path_str), |
| self.span, |
| context, |
| shape, |
| ) |
| } |
| PatKind::Lit(ref expr) => expr.rewrite(context, shape), |
| PatKind::Slice(ref prefix, ref slice_pat, ref suffix) => { |
| // Rewrite all the sub-patterns. |
| let prefix = prefix.iter().map(|p| p.rewrite(context, shape)); |
| let slice_pat = slice_pat |
| .as_ref() |
| .and_then(|p| p.rewrite(context, shape)) |
| .map(|rw| Some(format!("{}..", if rw == "_" { "" } else { &rw }))); |
| let suffix = suffix.iter().map(|p| p.rewrite(context, shape)); |
| |
| // Munge them together. |
| let pats: Option<Vec<String>> = |
| prefix.chain(slice_pat.into_iter()).chain(suffix).collect(); |
| |
| // Check that all the rewrites succeeded, and if not return `None`. |
| let pats = pats?; |
| |
| // Unwrap all the sub-strings and join them with commas. |
| Some(format!("[{}]", pats.join(", "))) |
| } |
| PatKind::Struct(ref path, ref fields, ellipsis) => { |
| rewrite_struct_pat(path, fields, ellipsis, self.span, context, shape) |
| } |
| PatKind::Mac(ref mac) => rewrite_macro(mac, None, context, shape, MacroPosition::Pat), |
| PatKind::Paren(ref pat) => pat |
| .rewrite(context, shape.offset_left(1)?.sub_width(1)?) |
| .map(|inner_pat| format!("({})", inner_pat)), |
| } |
| } |
| } |
| |
| fn rewrite_struct_pat( |
| path: &ast::Path, |
| fields: &[source_map::Spanned<ast::FieldPat>], |
| ellipsis: bool, |
| span: Span, |
| context: &RewriteContext<'_>, |
| shape: Shape, |
| ) -> Option<String> { |
| // 2 = ` {` |
| let path_shape = shape.sub_width(2)?; |
| let path_str = rewrite_path(context, PathContext::Expr, None, path, path_shape)?; |
| |
| if fields.is_empty() && !ellipsis { |
| return Some(format!("{} {{}}", path_str)); |
| } |
| |
| let (ellipsis_str, terminator) = if ellipsis { (", ..", "..") } else { ("", "}") }; |
| |
| // 3 = ` { `, 2 = ` }`. |
| let (h_shape, v_shape) = |
| struct_lit_shape(shape, context, path_str.len() + 3, ellipsis_str.len() + 2)?; |
| |
| let items = itemize_list( |
| context.snippet_provider, |
| fields.iter(), |
| terminator, |
| ",", |
| |f| f.span.lo(), |
| |f| f.span.hi(), |
| |f| f.node.rewrite(context, v_shape), |
| context.snippet_provider.span_after(span, "{"), |
| span.hi(), |
| false, |
| ); |
| let item_vec = items.collect::<Vec<_>>(); |
| |
| let tactic = struct_lit_tactic(h_shape, context, &item_vec); |
| let nested_shape = shape_for_tactic(tactic, h_shape, v_shape); |
| let fmt = struct_lit_formatting(nested_shape, tactic, context, false); |
| |
| let mut fields_str = write_list(&item_vec, &fmt)?; |
| let one_line_width = h_shape.map_or(0, |shape| shape.width); |
| |
| if ellipsis { |
| if fields_str.contains('\n') || fields_str.len() > one_line_width { |
| // Add a missing trailing comma. |
| if context.config.trailing_comma() == SeparatorTactic::Never { |
| fields_str.push_str(","); |
| } |
| fields_str.push_str("\n"); |
| fields_str.push_str(&nested_shape.indent.to_string(context.config)); |
| fields_str.push_str(".."); |
| } else { |
| if !fields_str.is_empty() { |
| // there are preceding struct fields being matched on |
| if tactic == DefinitiveListTactic::Vertical { |
| // if the tactic is Vertical, write_list already added a trailing , |
| fields_str.push_str(" "); |
| } else { |
| fields_str.push_str(", "); |
| } |
| } |
| fields_str.push_str(".."); |
| } |
| } |
| |
| // ast::Pat doesn't have attrs so use &[] |
| let fields_str = wrap_struct_field(context, &[], &fields_str, shape, v_shape, one_line_width)?; |
| Some(format!("{} {{{}}}", path_str, fields_str)) |
| } |
| |
| impl Rewrite for FieldPat { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| let pat = self.pat.rewrite(context, shape); |
| if self.is_shorthand { |
| pat |
| } else { |
| let pat_str = pat?; |
| let id_str = rewrite_ident(context, self.ident); |
| let one_line_width = id_str.len() + 2 + pat_str.len(); |
| if one_line_width <= shape.width { |
| Some(format!("{}: {}", id_str, pat_str)) |
| } else { |
| let nested_shape = shape.block_indent(context.config.tab_spaces()); |
| let pat_str = self.pat.rewrite(context, nested_shape)?; |
| Some(format!( |
| "{}:\n{}{}", |
| id_str, |
| nested_shape.indent.to_string(context.config), |
| pat_str, |
| )) |
| } |
| } |
| } |
| } |
| |
| #[derive(Debug)] |
| pub(crate) enum TuplePatField<'a> { |
| Pat(&'a ptr::P<ast::Pat>), |
| Dotdot(Span), |
| } |
| |
| impl<'a> Rewrite for TuplePatField<'a> { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| match *self { |
| TuplePatField::Pat(p) => p.rewrite(context, shape), |
| TuplePatField::Dotdot(_) => Some("..".to_string()), |
| } |
| } |
| } |
| |
| impl<'a> Spanned for TuplePatField<'a> { |
| fn span(&self) -> Span { |
| match *self { |
| TuplePatField::Pat(p) => p.span(), |
| TuplePatField::Dotdot(span) => span, |
| } |
| } |
| } |
| |
| pub(crate) fn can_be_overflowed_pat( |
| context: &RewriteContext<'_>, |
| pat: &TuplePatField<'_>, |
| len: usize, |
| ) -> bool { |
| match *pat { |
| TuplePatField::Pat(pat) => match pat.node { |
| ast::PatKind::Path(..) |
| | ast::PatKind::Tuple(..) |
| | ast::PatKind::Struct(..) |
| | ast::PatKind::TupleStruct(..) => context.use_block_indent() && len == 1, |
| ast::PatKind::Ref(ref p, _) | ast::PatKind::Box(ref p) => { |
| can_be_overflowed_pat(context, &TuplePatField::Pat(p), len) |
| } |
| ast::PatKind::Lit(ref expr) => can_be_overflowed_expr(context, expr, len), |
| _ => false, |
| }, |
| TuplePatField::Dotdot(..) => false, |
| } |
| } |
| |
| fn rewrite_tuple_pat( |
| pats: &[ptr::P<ast::Pat>], |
| dotdot_pos: Option<usize>, |
| path_str: Option<String>, |
| span: Span, |
| context: &RewriteContext<'_>, |
| shape: Shape, |
| ) -> Option<String> { |
| let mut pat_vec: Vec<_> = pats.iter().map(|x| TuplePatField::Pat(x)).collect(); |
| |
| if let Some(pos) = dotdot_pos { |
| let prev = if pos == 0 { |
| span.lo() |
| } else { |
| pats[pos - 1].span().hi() |
| }; |
| let next = if pos + 1 >= pats.len() { |
| span.hi() |
| } else { |
| pats[pos + 1].span().lo() |
| }; |
| let dot_span = mk_sp(prev, next); |
| let snippet = context.snippet(dot_span); |
| let lo = dot_span.lo() + BytePos(snippet.find_uncommented("..").unwrap() as u32); |
| let dotdot = TuplePatField::Dotdot(Span::new( |
| lo, |
| // 2 == "..".len() |
| lo + BytePos(2), |
| source_map::NO_EXPANSION, |
| )); |
| pat_vec.insert(pos, dotdot); |
| } |
| if pat_vec.is_empty() { |
| return Some(format!("{}()", path_str.unwrap_or_default())); |
| } |
| let wildcard_suffix_len = count_wildcard_suffix_len(context, &pat_vec, span, shape); |
| let (pat_vec, span, condensed) = |
| if context.config.condense_wildcard_suffixes() && wildcard_suffix_len >= 2 { |
| let new_item_count = 1 + pat_vec.len() - wildcard_suffix_len; |
| let sp = pat_vec[new_item_count - 1].span(); |
| let snippet = context.snippet(sp); |
| let lo = sp.lo() + BytePos(snippet.find_uncommented("_").unwrap() as u32); |
| pat_vec[new_item_count - 1] = TuplePatField::Dotdot(mk_sp(lo, lo + BytePos(1))); |
| ( |
| &pat_vec[..new_item_count], |
| mk_sp(span.lo(), lo + BytePos(1)), |
| true, |
| ) |
| } else { |
| (&pat_vec[..], span, false) |
| }; |
| |
| // add comma if `(x,)` |
| let add_comma = path_str.is_none() && pat_vec.len() == 1 && dotdot_pos.is_none() && !condensed; |
| let path_str = path_str.unwrap_or_default(); |
| |
| overflow::rewrite_with_parens( |
| &context, |
| &path_str, |
| pat_vec.iter(), |
| shape, |
| span, |
| context.config.max_width(), |
| if dotdot_pos.is_some() { |
| Some(SeparatorTactic::Never) |
| } else if add_comma { |
| Some(SeparatorTactic::Always) |
| } else { |
| None |
| }, |
| ) |
| } |
| |
| fn count_wildcard_suffix_len( |
| context: &RewriteContext<'_>, |
| patterns: &[TuplePatField<'_>], |
| span: Span, |
| shape: Shape, |
| ) -> usize { |
| let mut suffix_len = 0; |
| |
| let items: Vec<_> = itemize_list( |
| context.snippet_provider, |
| patterns.iter(), |
| ")", |
| ",", |
| |item| item.span().lo(), |
| |item| item.span().hi(), |
| |item| item.rewrite(context, shape), |
| context.snippet_provider.span_after(span, "("), |
| span.hi() - BytePos(1), |
| false, |
| ) |
| .collect(); |
| |
| for item in items.iter().rev().take_while(|i| match i.item { |
| Some(ref internal_string) if internal_string == "_" => true, |
| _ => false, |
| }) { |
| suffix_len += 1; |
| |
| if item.has_comment() { |
| break; |
| } |
| } |
| |
| suffix_len |
| } |