373 lines
13 KiB
Rust
373 lines
13 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use Shape;
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use codemap::SpanUtils;
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use rewrite::{Rewrite, RewriteContext};
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use utils::{wrap_str, format_mutability, mk_sp};
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use lists::{DefinitiveListTactic, SeparatorTactic, itemize_list, struct_lit_shape,
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struct_lit_tactic, shape_for_tactic, struct_lit_formatting, write_list};
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use expr::{rewrite_call_inner, rewrite_unary_prefix, rewrite_pair, can_be_overflowed_expr,
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wrap_struct_field};
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use types::{rewrite_path, PathContext};
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use super::Spanned;
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use comment::FindUncommented;
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use syntax::ast::{self, BindingMode, Pat, PatKind, FieldPat, RangeEnd};
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use syntax::ptr;
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use syntax::codemap::{self, BytePos, Span};
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impl Rewrite for Pat {
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fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
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match self.node {
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PatKind::Box(ref pat) => rewrite_unary_prefix(context, "box ", &**pat, shape),
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PatKind::Ident(binding_mode, ident, ref sub_pat) => {
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let (prefix, mutability) = match binding_mode {
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BindingMode::ByRef(mutability) => ("ref ", mutability),
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BindingMode::ByValue(mutability) => ("", mutability),
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};
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let mut_infix = format_mutability(mutability);
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let id_str = ident.node.to_string();
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let sub_pat = match *sub_pat {
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Some(ref p) => {
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// 3 - ` @ `.
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let width = try_opt!(
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shape
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.width
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.checked_sub(prefix.len() + mut_infix.len() + id_str.len() + 3)
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);
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format!(
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" @ {}",
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try_opt!(p.rewrite(context, Shape::legacy(width, shape.indent)))
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)
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}
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None => "".to_owned(),
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};
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let result = format!("{}{}{}{}", prefix, mut_infix, id_str, sub_pat);
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wrap_str(result, context.config.max_width(), shape)
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}
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PatKind::Wild => {
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if 1 <= shape.width {
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Some("_".to_owned())
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} else {
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None
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}
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}
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PatKind::Range(ref lhs, ref rhs, ref end_kind) => {
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match *end_kind {
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RangeEnd::Included => {
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rewrite_pair(&**lhs, &**rhs, "", "...", "", context, shape)
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}
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RangeEnd::Excluded => {
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rewrite_pair(&**lhs, &**rhs, "", "..", "", context, shape)
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}
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}
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}
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PatKind::Ref(ref pat, mutability) => {
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let prefix = format!("&{}", format_mutability(mutability));
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rewrite_unary_prefix(context, &prefix, &**pat, shape)
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}
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PatKind::Tuple(ref items, dotdot_pos) => {
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rewrite_tuple_pat(items, dotdot_pos, None, self.span, context, shape)
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}
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PatKind::Path(ref q_self, ref path) => {
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rewrite_path(context, PathContext::Expr, q_self.as_ref(), path, shape)
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}
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PatKind::TupleStruct(ref path, ref pat_vec, dotdot_pos) => {
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let path_str =
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try_opt!(rewrite_path(context, PathContext::Expr, None, path, shape));
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rewrite_tuple_pat(
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pat_vec,
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dotdot_pos,
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Some(path_str),
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self.span,
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context,
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shape,
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)
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}
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PatKind::Lit(ref expr) => expr.rewrite(context, shape),
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PatKind::Slice(ref prefix, ref slice_pat, ref suffix) => {
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// Rewrite all the sub-patterns.
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let prefix = prefix.iter().map(|p| p.rewrite(context, shape));
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let slice_pat = slice_pat.as_ref().map(|p| {
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Some(format!("{}..", try_opt!(p.rewrite(context, shape))))
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});
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let suffix = suffix.iter().map(|p| p.rewrite(context, shape));
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// Munge them together.
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let pats: Option<Vec<String>> =
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prefix.chain(slice_pat.into_iter()).chain(suffix).collect();
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// Check that all the rewrites succeeded, and if not return None.
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let pats = try_opt!(pats);
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// Unwrap all the sub-strings and join them with commas.
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let result = if context.config.spaces_within_square_brackets() {
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format!("[ {} ]", pats.join(", "))
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} else {
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format!("[{}]", pats.join(", "))
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};
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wrap_str(result, context.config.max_width(), shape)
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}
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PatKind::Struct(ref path, ref fields, elipses) => {
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rewrite_struct_pat(path, fields, elipses, self.span, context, shape)
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}
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// FIXME(#819) format pattern macros.
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PatKind::Mac(..) => {
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wrap_str(
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context.snippet(self.span),
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context.config.max_width(),
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shape,
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)
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}
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}
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}
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}
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fn rewrite_struct_pat(
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path: &ast::Path,
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fields: &[codemap::Spanned<ast::FieldPat>],
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elipses: bool,
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span: Span,
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context: &RewriteContext,
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shape: Shape,
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) -> Option<String> {
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// 2 = ` {`
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let path_shape = try_opt!(shape.sub_width(2));
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let path_str = try_opt!(rewrite_path(
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context,
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PathContext::Expr,
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None,
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path,
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path_shape,
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));
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if fields.len() == 0 && !elipses {
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return Some(format!("{} {{}}", path_str));
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}
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let (elipses_str, terminator) = if elipses { (", ..", "..") } else { ("", "}") };
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// 3 = ` { `, 2 = ` }`.
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let (h_shape, v_shape) = try_opt!(struct_lit_shape(
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shape,
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context,
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path_str.len() + 3,
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elipses_str.len() + 2,
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));
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let items = itemize_list(
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context.codemap,
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fields.iter(),
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terminator,
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|f| f.span.lo,
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|f| f.span.hi,
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|f| f.node.rewrite(context, v_shape),
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context.codemap.span_after(span, "{"),
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span.hi,
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);
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let item_vec = items.collect::<Vec<_>>();
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let tactic = struct_lit_tactic(h_shape, context, &item_vec);
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let nested_shape = shape_for_tactic(tactic, h_shape, v_shape);
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let fmt = struct_lit_formatting(nested_shape, tactic, context, false);
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let mut fields_str = try_opt!(write_list(&item_vec, &fmt));
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let one_line_width = h_shape.map_or(0, |shape| shape.width);
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if elipses {
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if fields_str.contains('\n') || fields_str.len() > one_line_width {
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// Add a missing trailing comma.
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if fmt.trailing_separator == SeparatorTactic::Never {
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fields_str.push_str(",");
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}
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fields_str.push_str("\n");
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fields_str.push_str(&nested_shape.indent.to_string(context.config));
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fields_str.push_str("..");
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} else {
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if !fields_str.is_empty() {
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// there are preceeding struct fields being matched on
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if fmt.tactic == DefinitiveListTactic::Vertical {
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// if the tactic is Vertical, write_list already added a trailing ,
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fields_str.push_str(" ");
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} else {
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fields_str.push_str(", ");
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}
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}
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fields_str.push_str("..");
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}
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}
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let fields_str = wrap_struct_field(context, &fields_str, shape, v_shape, one_line_width);
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Some(format!("{} {{{}}}", path_str, fields_str))
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}
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impl Rewrite for FieldPat {
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fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
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let pat = self.pat.rewrite(context, shape);
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if self.is_shorthand {
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pat
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} else {
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wrap_str(
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format!("{}: {}", self.ident.to_string(), try_opt!(pat)),
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context.config.max_width(),
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shape,
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)
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}
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}
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}
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pub enum TuplePatField<'a> {
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Pat(&'a ptr::P<ast::Pat>),
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Dotdot(Span),
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}
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impl<'a> Rewrite for TuplePatField<'a> {
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fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
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match *self {
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TuplePatField::Pat(ref p) => p.rewrite(context, shape),
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TuplePatField::Dotdot(_) => Some("..".to_string()),
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}
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}
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}
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impl<'a> Spanned for TuplePatField<'a> {
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fn span(&self) -> Span {
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match *self {
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TuplePatField::Pat(ref p) => p.span(),
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TuplePatField::Dotdot(span) => span,
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}
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}
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}
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pub fn can_be_overflowed_pat(context: &RewriteContext, pat: &TuplePatField, len: usize) -> bool {
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match pat {
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&TuplePatField::Pat(ref pat) => {
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match pat.node {
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ast::PatKind::Path(..) | ast::PatKind::Tuple(..) | ast::PatKind::Struct(..) => {
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context.use_block_indent() && len == 1
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}
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ast::PatKind::Ref(ref p, _) | ast::PatKind::Box(ref p) => {
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can_be_overflowed_pat(context, &TuplePatField::Pat(p), len)
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}
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ast::PatKind::Lit(ref expr) => can_be_overflowed_expr(context, expr, len),
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_ => false,
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}
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}
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&TuplePatField::Dotdot(..) => false,
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}
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}
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fn rewrite_tuple_pat(
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pats: &[ptr::P<ast::Pat>],
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dotdot_pos: Option<usize>,
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path_str: Option<String>,
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span: Span,
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context: &RewriteContext,
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shape: Shape,
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) -> Option<String> {
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let mut pat_vec: Vec<_> = pats.into_iter().map(|x| TuplePatField::Pat(x)).collect();
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if let Some(pos) = dotdot_pos {
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let prev = if pos == 0 {
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span.lo
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} else {
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pats[pos - 1].span().hi
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};
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let next = if pos + 1 >= pats.len() {
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span.hi
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} else {
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pats[pos + 1].span().lo
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};
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let dot_span = mk_sp(prev, next);
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let snippet = context.snippet(dot_span);
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let lo = dot_span.lo + BytePos(snippet.find_uncommented("..").unwrap() as u32);
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let dotdot = TuplePatField::Dotdot(Span {
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lo: lo,
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// 2 == "..".len()
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hi: lo + BytePos(2),
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ctxt: codemap::NO_EXPANSION,
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});
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pat_vec.insert(pos, dotdot);
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}
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if pat_vec.is_empty() {
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return Some(format!("{}()", try_opt!(path_str)));
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}
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let wildcard_suffix_len = count_wildcard_suffix_len(context, &pat_vec, span, shape);
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let (pat_vec, span) =
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if context.config.condense_wildcard_suffixes() && wildcard_suffix_len >= 2 {
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let new_item_count = 1 + pat_vec.len() - wildcard_suffix_len;
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let sp = pat_vec[new_item_count - 1].span();
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let snippet = context.snippet(sp);
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let lo = sp.lo + BytePos(snippet.find_uncommented("_").unwrap() as u32);
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pat_vec[new_item_count - 1] = TuplePatField::Dotdot(mk_sp(lo, lo + BytePos(1)));
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(&pat_vec[..new_item_count], mk_sp(span.lo, lo + BytePos(1)))
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} else {
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(&pat_vec[..], span)
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};
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// add comma if `(x,)`
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let add_comma = path_str.is_none() && pat_vec.len() == 1 && dotdot_pos.is_none();
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let mut context = context.clone();
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if let Some(&TuplePatField::Dotdot(..)) = pat_vec.last() {
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context.inside_macro = true;
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}
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let path_str = path_str.unwrap_or(String::new());
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let mut pat_ref_vec = Vec::with_capacity(pat_vec.len());
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for pat in pat_vec {
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pat_ref_vec.push(pat);
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}
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return rewrite_call_inner(
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&context,
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&path_str,
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&pat_ref_vec[..],
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span,
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shape,
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shape.width,
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add_comma,
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).ok();
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}
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fn count_wildcard_suffix_len(
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context: &RewriteContext,
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patterns: &[TuplePatField],
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span: Span,
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shape: Shape,
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) -> usize {
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let mut suffix_len = 0;
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let items: Vec<_> = itemize_list(
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context.codemap,
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patterns.iter(),
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")",
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|item| item.span().lo,
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|item| item.span().hi,
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|item| item.rewrite(context, shape),
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context.codemap.span_after(span, "("),
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span.hi - BytePos(1),
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).collect();
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for item in items.iter().rev().take_while(|i| match i.item {
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Some(ref internal_string) if internal_string == "_" => true,
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_ => false,
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}) {
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suffix_len += 1;
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if item.pre_comment.is_some() || item.post_comment.is_some() {
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break;
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}
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}
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suffix_len
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}
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