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rust / rustfmt / 39a91ba292af829bc6b678d19f475d91076c3166 / . / src / items.rs
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Formatting top-level items - functions, structs, enums, traits, impls.
use std::cmp::min;
use syntax::{abi, ast, ptr, symbol};
use syntax::ast::ImplItem;
use syntax::codemap::{BytePos, Span};
use {Indent, Shape, Spanned};
use codemap::{LineRangeUtils, SpanUtils};
use comment::{combine_strs_with_missing_comments, contains_comment, recover_comment_removed,
recover_missing_comment_in_span, rewrite_missing_comment, FindUncommented};
use config::{BraceStyle, Config, Density, IndentStyle, ReturnIndent, Style};
use expr::{format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs,
rewrite_call_inner, ExprType};
use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting,
ListItem, ListTactic, Separator, SeparatorPlace, SeparatorTactic};
use rewrite::{Rewrite, RewriteContext};
use types::join_bounds;
use utils::{colon_spaces, contains_skip, end_typaram, first_line_width, format_abi,
format_constness, format_defaultness, format_mutability, format_unsafety,
format_visibility, is_attributes_extendable, last_line_contains_single_line_comment,
last_line_used_width, last_line_width, mk_sp, semicolon_for_expr, stmt_expr,
trim_newlines, trimmed_last_line_width, wrap_str};
use vertical::rewrite_with_alignment;
use visitor::FmtVisitor;
fn type_annotation_separator(config: &Config) -> &str {
colon_spaces(
config.space_before_type_annotation(),
config.space_after_type_annotation_colon(),
)
}
// Statements of the form
// let pat: ty = init;
impl Rewrite for ast::Local {
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
debug!(
"Local::rewrite {:?} {} {:?}",
self,
shape.width,
shape.indent
);
skip_out_of_file_lines_range!(context, self.span);
if contains_skip(&self.attrs) {
return None;
}
let attrs_str = try_opt!(self.attrs.rewrite(context, shape));
let mut result = if attrs_str.is_empty() {
"let ".to_owned()
} else {
try_opt!(combine_strs_with_missing_comments(
context,
&attrs_str,
"let ",
mk_sp(
self.attrs.last().map(|a| a.span.hi()).unwrap(),
self.span.lo(),
),
shape,
false,
))
};
// 4 = "let ".len()
let pat_shape = try_opt!(shape.offset_left(4));
// 1 = ;
let pat_shape = try_opt!(pat_shape.sub_width(1));
let pat_str = try_opt!(self.pat.rewrite(&context, pat_shape));
result.push_str(&pat_str);
// String that is placed within the assignment pattern and expression.
let infix = {
let mut infix = String::with_capacity(32);
if let Some(ref ty) = self.ty {
let separator = type_annotation_separator(context.config);
let indent = shape.indent + last_line_width(&result) + separator.len();
// 1 = ;
let budget = try_opt!(shape.width.checked_sub(indent.width() + 1));
let rewrite = try_opt!(ty.rewrite(context, Shape::legacy(budget, indent)));
infix.push_str(separator);
infix.push_str(&rewrite);
}
if self.init.is_some() {
infix.push_str(" =");
}
infix
};
result.push_str(&infix);
if let Some(ref ex) = self.init {
// 1 = trailing semicolon;
let nested_shape = try_opt!(shape.sub_width(1));
result = try_opt!(rewrite_assign_rhs(&context, result, ex, nested_shape));
}
result.push(';');
Some(result)
}
}
// TODO convert to using rewrite style rather than visitor
// TODO format modules in this style
#[allow(dead_code)]
struct Item<'a> {
keyword: &'static str,
abi: String,
vis: Option<&'a ast::Visibility>,
body: Vec<BodyElement<'a>>,
span: Span,
}
impl<'a> Item<'a> {
fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Item<'a> {
let abi = if fm.abi == abi::Abi::C && !config.force_explicit_abi() {
"extern".into()
} else {
format!("extern {}", fm.abi)
};
Item {
keyword: "",
abi: abi,
vis: None,
body: fm.items
.iter()
.map(|i| BodyElement::ForeignItem(i))
.collect(),
span: span,
}
}
}
enum BodyElement<'a> {
// Stmt(&'a ast::Stmt),
// Field(&'a ast::Field),
// Variant(&'a ast::Variant),
// Item(&'a ast::Item),
ForeignItem(&'a ast::ForeignItem),
}
impl<'a> FmtVisitor<'a> {
fn format_item(&mut self, item: Item) {
self.buffer.push_str(&item.abi);
self.buffer.push_str(" ");
let snippet = self.snippet(item.span);
let brace_pos = snippet.find_uncommented("{").unwrap();
self.buffer.push_str("{");
if !item.body.is_empty() || contains_comment(&snippet[brace_pos..]) {
// FIXME: this skips comments between the extern keyword and the opening
// brace.
self.last_pos = item.span.lo() + BytePos(brace_pos as u32 + 1);
self.block_indent = self.block_indent.block_indent(self.config);
if item.body.is_empty() {
self.format_missing_no_indent(item.span.hi() - BytePos(1));
self.block_indent = self.block_indent.block_unindent(self.config);
self.buffer
.push_str(&self.block_indent.to_string(self.config));
} else {
for item in &item.body {
self.format_body_element(item);
}
self.block_indent = self.block_indent.block_unindent(self.config);
self.format_missing_with_indent(item.span.hi() - BytePos(1));
}
}
self.buffer.push_str("}");
self.last_pos = item.span.hi();
}
fn format_body_element(&mut self, element: &BodyElement) {
match *element {
BodyElement::ForeignItem(ref item) => self.format_foreign_item(item),
}
}
pub fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) {
let item = Item::from_foreign_mod(fm, span, self.config);
self.format_item(item);
}
fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
let rewrite = item.rewrite(&self.get_context(), self.shape());
self.push_rewrite(item.span(), rewrite);
self.last_pos = item.span.hi();
}
pub fn rewrite_fn(
&mut self,
indent: Indent,
ident: ast::Ident,
fd: &ast::FnDecl,
generics: &ast::Generics,
unsafety: ast::Unsafety,
constness: ast::Constness,
defaultness: ast::Defaultness,
abi: abi::Abi,
vis: &ast::Visibility,
span: Span,
block: &ast::Block,
) -> Option<String> {
let context = self.get_context();
let block_snippet = self.snippet(mk_sp(block.span.lo(), block.span.hi()));
let has_body = !block_snippet[1..block_snippet.len() - 1].trim().is_empty() ||
!context.config.fn_empty_single_line();
let mut newline_brace = newline_for_brace(self.config, &generics.where_clause, has_body);
let (mut result, force_newline_brace) = try_opt!(rewrite_fn_base(
&context,
indent,
ident,
fd,
generics,
unsafety,
constness,
defaultness,
abi,
vis,
span,
newline_brace,
has_body,
true,
));
if force_newline_brace {
newline_brace = true;
} else if self.config.fn_brace_style() != BraceStyle::AlwaysNextLine &&
!result.contains('\n')
{
newline_brace = false;
}
// Prepare for the function body by possibly adding a newline and
// indent.
// FIXME we'll miss anything between the end of the signature and the
// start of the body, but we need more spans from the compiler to solve
// this.
if newline_brace {
result.push('\n');
result.push_str(&indent.to_string(self.config));
} else {
result.push(' ');
}
self.single_line_fn(&result, block).or_else(|| Some(result))
}
pub fn rewrite_required_fn(
&mut self,
indent: Indent,
ident: ast::Ident,
sig: &ast::MethodSig,
span: Span,
) -> Option<String> {
// Drop semicolon or it will be interpreted as comment.
let span = mk_sp(span.lo(), span.hi() - BytePos(1));
let context = self.get_context();
let (mut result, _) = try_opt!(rewrite_fn_base(
&context,
indent,
ident,
&sig.decl,
&sig.generics,
sig.unsafety,
sig.constness.node,
ast::Defaultness::Final,
sig.abi,
&ast::Visibility::Inherited,
span,
false,
false,
false,
));
// Re-attach semicolon
result.push(';');
Some(result)
}
fn single_line_fn(&self, fn_str: &str, block: &ast::Block) -> Option<String> {
if fn_str.contains('\n') {
return None;
}
let codemap = self.get_context().codemap;
if self.config.fn_empty_single_line() && is_empty_block(block, codemap) &&
self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width()
{
return Some(format!("{}{{}}", fn_str));
}
if self.config.fn_single_line() && is_simple_block_stmt(block, codemap) {
let rewrite = {
if let Some(ref stmt) = block.stmts.first() {
match stmt_expr(stmt) {
Some(e) => {
let suffix = if semicolon_for_expr(&self.get_context(), e) {
";"
} else {
""
};
format_expr(&e, ExprType::Statement, &self.get_context(), self.shape())
.map(|s| s + suffix)
.or_else(|| Some(self.snippet(e.span)))
}
None => stmt.rewrite(&self.get_context(), self.shape()),
}
} else {
None
}
};
if let Some(res) = rewrite {
let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
if !res.contains('\n') && width <= self.config.max_width() {
return Some(format!("{}{{ {} }}", fn_str, res));
}
}
}
None
}
pub fn visit_enum(
&mut self,
ident: ast::Ident,
vis: &ast::Visibility,
enum_def: &ast::EnumDef,
generics: &ast::Generics,
span: Span,
) {
let enum_header = format_header("enum ", ident, vis);
self.buffer.push_str(&enum_header);
let enum_snippet = self.snippet(span);
let brace_pos = enum_snippet.find_uncommented("{").unwrap();
let body_start = span.lo() + BytePos(brace_pos as u32 + 1);
let generics_str = format_generics(
&self.get_context(),
generics,
"{",
"{",
self.config.item_brace_style(),
enum_def.variants.is_empty(),
self.block_indent,
mk_sp(span.lo(), body_start),
last_line_width(&enum_header),
).unwrap();
self.buffer.push_str(&generics_str);
self.last_pos = body_start;
self.block_indent = self.block_indent.block_indent(self.config);
let variant_list = self.format_variant_list(enum_def, body_start, span.hi() - BytePos(1));
match variant_list {
Some(ref body_str) => self.buffer.push_str(body_str),
None => if contains_comment(&enum_snippet[brace_pos..]) {
self.format_missing_no_indent(span.hi() - BytePos(1))
} else {
self.format_missing(span.hi() - BytePos(1))
},
}
self.block_indent = self.block_indent.block_unindent(self.config);
if variant_list.is_some() || contains_comment(&enum_snippet[brace_pos..]) {
self.buffer
.push_str(&self.block_indent.to_string(self.config));
}
self.buffer.push_str("}");
self.last_pos = span.hi();
}
// Format the body of an enum definition
fn format_variant_list(
&self,
enum_def: &ast::EnumDef,
body_lo: BytePos,
body_hi: BytePos,
) -> Option<String> {
if enum_def.variants.is_empty() {
return None;
}
let mut result = String::with_capacity(1024);
result.push('\n');
let indentation = self.block_indent.to_string(self.config);
result.push_str(&indentation);
let items = itemize_list(
self.codemap,
enum_def.variants.iter(),
"}",
|f| if !f.node.attrs.is_empty() {
f.node.attrs[0].span.lo()
} else {
f.span.lo()
},
|f| f.span.hi(),
|f| self.format_variant(f),
body_lo,
body_hi,
false,
);
let shape = self.shape().sub_width(2).unwrap();
let fmt = ListFormatting {
tactic: DefinitiveListTactic::Vertical,
separator: ",",
trailing_separator: self.config.trailing_comma(),
separator_place: SeparatorPlace::Back,
shape: shape,
ends_with_newline: true,
preserve_newline: true,
config: self.config,
};
let list = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
result.push_str(&list);
result.push('\n');
Some(result)
}
// Variant of an enum.
fn format_variant(&self, field: &ast::Variant) -> Option<String> {
if contains_skip(&field.node.attrs) {
let lo = field.node.attrs[0].span.lo();
let span = mk_sp(lo, field.span.hi());
return Some(self.snippet(span));
}
let context = self.get_context();
let indent = self.block_indent;
let shape = self.shape();
let attrs_str = try_opt!(field.node.attrs.rewrite(&context, shape));
let lo = field
.node
.attrs
.last()
.map_or(field.span.lo(), |attr| attr.span.hi());
let span = mk_sp(lo, field.span.lo());
let variant_body = match field.node.data {
ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => {
// FIXME: Should limit the width, as we have a trailing comma
try_opt!(format_struct(
&context,
"",
field.node.name,
&ast::Visibility::Inherited,
&field.node.data,
None,
field.span,
indent,
Some(self.config.struct_variant_width()),
))
}
ast::VariantData::Unit(..) => if let Some(ref expr) = field.node.disr_expr {
let one_line_width =
field.node.name.to_string().len() + self.snippet(expr.span).len() + 3;
if one_line_width <= shape.width {
format!("{} = {}", field.node.name, self.snippet(expr.span))
} else {
format!(
"{}\n{}{}",
field.node.name,
shape
.indent
.block_indent(self.config)
.to_string(self.config),
self.snippet(expr.span)
)
}
} else {
String::from(field.node.name.to_string())
},
};
let attrs_extendable = attrs_str.is_empty() ||
(context.config.attributes_on_same_line_as_variant() &&
is_attributes_extendable(&attrs_str));
combine_strs_with_missing_comments(
&context,
&attrs_str,
&variant_body,
span,
shape,
attrs_extendable,
)
}
}
pub fn format_impl(
context: &RewriteContext,
item: &ast::Item,
offset: Indent,
where_span_end: Option<BytePos>,
) -> Option<String> {
if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
let mut result = String::with_capacity(128);
let ref_and_type = try_opt!(format_impl_ref_and_type(context, item, offset));
let indent_str = offset.to_string(context.config);
let sep = format!("\n{}", &indent_str);
result.push_str(&ref_and_type);
let where_budget = if result.contains('\n') {
context.config.max_width()
} else {
context
.config
.max_width()
.checked_sub(last_line_width(&result))
.unwrap_or(0)
};
let option = WhereClauseOption::snuggled(&ref_and_type);
let where_clause_str = try_opt!(rewrite_where_clause(
context,
&generics.where_clause,
context.config.item_brace_style(),
Shape::legacy(where_budget, offset.block_only()),
context.config.where_density(),
"{",
where_span_end,
self_ty.span.hi(),
option,
));
// If there is no where clause, we may have missing comments between the trait name and
// the opening brace.
if generics.where_clause.predicates.is_empty() {
if let Some(hi) = where_span_end {
match recover_missing_comment_in_span(
mk_sp(self_ty.span.hi(), hi),
Shape::indented(offset, context.config),
context,
last_line_width(&result),
) {
Some(ref missing_comment) if !missing_comment.is_empty() => {
result.push_str(missing_comment);
}
_ => (),
}
}
}
if try_opt!(is_impl_single_line(
context,
&items,
&result,
&where_clause_str,
&item,
)) {
result.push_str(&where_clause_str);
if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
result.push_str(&format!("{}{{{}}}", &sep, &sep));
} else {
result.push_str(" {}");
}
return Some(result);
}
if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
result.push('\n');
let width = offset.block_indent + context.config.tab_spaces() - 1;
let where_indent = Indent::new(0, width);
result.push_str(&where_indent.to_string(context.config));
}
result.push_str(&where_clause_str);
match context.config.item_brace_style() {
_ if last_line_contains_single_line_comment(&result) => result.push_str(&sep),
BraceStyle::AlwaysNextLine => result.push_str(&sep),
BraceStyle::PreferSameLine => result.push(' '),
BraceStyle::SameLineWhere => if !where_clause_str.is_empty() {
result.push_str(&sep);
} else {
result.push(' ');
},
}
result.push('{');
let snippet = context.snippet(item.span);
let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
visitor.block_indent = offset.block_only().block_indent(context.config);
visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
for item in items {
visitor.visit_impl_item(item);
}
visitor.format_missing(item.span.hi() - BytePos(1));
let inner_indent_str = visitor.block_indent.to_string(context.config);
let outer_indent_str = offset.block_only().to_string(context.config);
result.push('\n');
result.push_str(&inner_indent_str);
result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
result.push('\n');
result.push_str(&outer_indent_str);
}
if result.chars().last().unwrap() == '{' {
result.push_str(&sep);
}
result.push('}');
Some(result)
} else {
unreachable!();
}
}
fn is_impl_single_line(
context: &RewriteContext,
items: &[ImplItem],
result: &str,
where_clause_str: &str,
item: &ast::Item,
) -> Option<bool> {
let snippet = context.snippet(item.span);
let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
Some(
context.config.impl_empty_single_line() && items.is_empty() && !result.contains('\n') &&
result.len() + where_clause_str.len() <= context.config.max_width() &&
!contains_comment(&snippet[open_pos..]),
)
}
fn format_impl_ref_and_type(
context: &RewriteContext,
item: &ast::Item,
offset: Indent,
) -> Option<String> {
if let ast::ItemKind::Impl(
unsafety,
polarity,
defaultness,
ref generics,
ref trait_ref,
ref self_ty,
_,
) = item.node
{
let mut result = String::with_capacity(128);
result.push_str(&format_visibility(&item.vis));
result.push_str(&format_defaultness(defaultness));
result.push_str(format_unsafety(unsafety));
result.push_str("impl");
let lo = context.codemap.span_after(item.span, "impl");
let hi = match *trait_ref {
Some(ref tr) => tr.path.span.lo(),
None => self_ty.span.lo(),
};
let shape = try_opt!(generics_shape_from_config(
context.config,
Shape::indented(offset + last_line_width(&result), context.config),
0,
));
let one_line_budget = try_opt!(shape.width.checked_sub(last_line_width(&result) + 2));
let generics_str = try_opt!(rewrite_generics_inner(
context,
generics,
shape,
one_line_budget,
mk_sp(lo, hi),
));
let polarity_str = if polarity == ast::ImplPolarity::Negative {
"!"
} else {
""
};
if let Some(ref trait_ref) = *trait_ref {
let result_len = result.len();
if let Some(trait_ref_str) = rewrite_trait_ref(
context,
&trait_ref,
offset,
&generics_str,
true,
polarity_str,
result_len,
) {
result.push_str(&trait_ref_str);
} else {
let generics_str = try_opt!(rewrite_generics_inner(
context,
generics,
shape,
0,
mk_sp(lo, hi),
));
result.push_str(&try_opt!(rewrite_trait_ref(
context,
&trait_ref,
offset,
&generics_str,
false,
polarity_str,
result_len,
)));
}
} else {
result.push_str(&generics_str);
}
// Try to put the self type in a single line.
// ` for`
let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
// If there is no where clause adapt budget for type formatting to take space and curly
// brace into account.
match context.config.item_brace_style() {
BraceStyle::AlwaysNextLine => 0,
_ => 2,
}
} else {
0
};
let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
// 1 = space before the type.
let budget = context
.config
.max_width()
.checked_sub(used_space + 1)
.unwrap_or(0);
if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
if !self_ty_str.contains('\n') {
if trait_ref.is_some() {
result.push_str(" for ");
} else {
result.push(' ');
}
result.push_str(&self_ty_str);
return Some(result);
}
}
// Couldn't fit the self type on a single line, put it on a new line.
result.push('\n');
// Add indentation of one additional tab.
let new_line_offset = offset.block_indent(context.config);
result.push_str(&new_line_offset.to_string(context.config));
if trait_ref.is_some() {
result.push_str("for ");
}
let budget = context.config.max_width() - last_line_width(&result);
let type_offset = match context.config.where_style() {
Style::Legacy => new_line_offset + trait_ref_overhead,
Style::Rfc => new_line_offset,
};
result.push_str(&*try_opt!(
self_ty.rewrite(context, Shape::legacy(budget, type_offset))
));
Some(result)
} else {
unreachable!();
}
}
fn rewrite_trait_ref(
context: &RewriteContext,
trait_ref: &ast::TraitRef,
offset: Indent,
generics_str: &str,
retry: bool,
polarity_str: &str,
result_len: usize,
) -> Option<String> {
// 1 = space between generics and trait_ref
let used_space = 1 + polarity_str.len() + last_line_used_width(generics_str, result_len);
let shape = Shape::indented(offset + used_space, context.config);
if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
if !(retry && trait_ref_str.contains('\n')) {
return Some(format!(
"{} {}{}",
generics_str,
polarity_str,
&trait_ref_str
));
}
}
// We could not make enough space for trait_ref, so put it on new line.
if !retry {
let offset = offset.block_indent(context.config);
let shape = Shape::indented(offset, context.config);
let trait_ref_str = try_opt!(trait_ref.rewrite(context, shape));
Some(format!(
"{}\n{}{}{}",
generics_str,
&offset.to_string(context.config),
polarity_str,
&trait_ref_str
))
} else {
None
}
}
pub fn format_struct(
context: &RewriteContext,
item_name: &str,
ident: ast::Ident,
vis: &ast::Visibility,
struct_def: &ast::VariantData,
generics: Option<&ast::Generics>,
span: Span,
offset: Indent,
one_line_width: Option<usize>,
) -> Option<String> {
match *struct_def {
ast::VariantData::Unit(..) => Some(format_unit_struct(item_name, ident, vis)),
ast::VariantData::Tuple(ref fields, _) => format_tuple_struct(
context,
item_name,
ident,
vis,
fields,
generics,
span,
offset,
),
ast::VariantData::Struct(ref fields, _) => format_struct_struct(
context,
item_name,
ident,
vis,
fields,
generics,
span,
offset,
one_line_width,
),
}
}
pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
if let ast::ItemKind::Trait(unsafety, ref generics, ref type_param_bounds, ref trait_items) =
item.node
{
let mut result = String::with_capacity(128);
let header = format!(
"{}{}trait {}",
format_visibility(&item.vis),
format_unsafety(unsafety),
item.ident
);
result.push_str(&header);
let body_lo = context.codemap.span_after(item.span, "{");
let shape = Shape::indented(offset + last_line_width(&result), context.config);
let generics_str = try_opt!(rewrite_generics(
context,
generics,
shape,
mk_sp(item.span.lo(), body_lo),
));
result.push_str(&generics_str);
let trait_bound_str = try_opt!(rewrite_trait_bounds(
context,
type_param_bounds,
Shape::indented(offset, context.config),
));
// If the trait, generics, and trait bound cannot fit on the same line,
// put the trait bounds on an indented new line
if offset.width() + last_line_width(&result) + trait_bound_str.len() >
context.config.comment_width()
{
result.push('\n');
let trait_indent = offset.block_only().block_indent(context.config);
result.push_str(&trait_indent.to_string(context.config));
}
result.push_str(&trait_bound_str);
let has_body = !trait_items.is_empty();
let where_density = if (context.config.where_density() == Density::Compressed &&
(!result.contains('\n') || context.config.fn_args_layout() == IndentStyle::Block)) ||
(context.config.fn_args_layout() == IndentStyle::Block && result.is_empty()) ||
(context.config.where_density() == Density::CompressedIfEmpty && !has_body &&
!result.contains('\n'))
{
Density::Compressed
} else {
Density::Tall
};
let where_budget = try_opt!(
context
.config
.max_width()
.checked_sub(last_line_width(&result))
);
let pos_before_where = if type_param_bounds.is_empty() {
generics.where_clause.span.lo()
} else {
type_param_bounds[type_param_bounds.len() - 1].span().hi()
};
let option = WhereClauseOption::snuggled(&generics_str);
let where_clause_str = try_opt!(rewrite_where_clause(
context,
&generics.where_clause,
context.config.item_brace_style(),
Shape::legacy(where_budget, offset.block_only()),
where_density,
"{",
None,
pos_before_where,
option,
));
// If the where clause cannot fit on the same line,
// put the where clause on a new line
if !where_clause_str.contains('\n') &&
last_line_width(&result) + where_clause_str.len() + offset.width() >
context.config.comment_width()
{
result.push('\n');
let width = offset.block_indent + context.config.tab_spaces() - 1;
let where_indent = Indent::new(0, width);
result.push_str(&where_indent.to_string(context.config));
}
result.push_str(&where_clause_str);
if generics.where_clause.predicates.is_empty() {
let item_snippet = context.snippet(item.span);
if let Some(lo) = item_snippet.chars().position(|c| c == '/') {
// 1 = `{`
let comment_hi = body_lo - BytePos(1);
let comment_lo = item.span.lo() + BytePos(lo as u32);
if comment_lo < comment_hi {
match recover_missing_comment_in_span(
mk_sp(comment_lo, comment_hi),
Shape::indented(offset, context.config),
context,
last_line_width(&result),
) {
Some(ref missing_comment) if !missing_comment.is_empty() => {
result.push_str(missing_comment);
}
_ => (),
}
}
}
}
match context.config.item_brace_style() {
_ if last_line_contains_single_line_comment(&result) => {
result.push('\n');
result.push_str(&offset.to_string(context.config));
}
BraceStyle::AlwaysNextLine => {
result.push('\n');
result.push_str(&offset.to_string(context.config));
}
BraceStyle::PreferSameLine => result.push(' '),
BraceStyle::SameLineWhere => if !where_clause_str.is_empty() &&
(!trait_items.is_empty() || result.contains('\n'))
{
result.push('\n');
result.push_str(&offset.to_string(context.config));
} else {
result.push(' ');
},
}
result.push('{');
let snippet = context.snippet(item.span);
let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
visitor.block_indent = offset.block_only().block_indent(context.config);
visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
for item in trait_items {
visitor.visit_trait_item(item);
}
visitor.format_missing(item.span.hi() - BytePos(1));
let inner_indent_str = visitor.block_indent.to_string(context.config);
let outer_indent_str = offset.block_only().to_string(context.config);
result.push('\n');
result.push_str(&inner_indent_str);
result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
result.push('\n');
result.push_str(&outer_indent_str);
} else if result.contains('\n') {
result.push('\n');
}
result.push('}');
Some(result)
} else {
unreachable!();
}
}
fn format_unit_struct(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
format!("{};", format_header(item_name, ident, vis))
}
pub fn format_struct_struct(
context: &RewriteContext,
item_name: &str,
ident: ast::Ident,
vis: &ast::Visibility,
fields: &[ast::StructField],
generics: Option<&ast::Generics>,
span: Span,
offset: Indent,
one_line_width: Option<usize>,
) -> Option<String> {
let mut result = String::with_capacity(1024);
let header_str = format_header(item_name, ident, vis);
result.push_str(&header_str);
let body_lo = context.codemap.span_after(span, "{");
let generics_str = match generics {
Some(g) => try_opt!(format_generics(
context,
g,
"{",
"{",
context.config.item_brace_style(),
fields.is_empty(),
offset,
mk_sp(span.lo(), body_lo),
last_line_width(&result),
)),
None => {
// 3 = ` {}`, 2 = ` {`.
let overhead = if fields.is_empty() { 3 } else { 2 };
if (context.config.item_brace_style() == BraceStyle::AlwaysNextLine &&
!fields.is_empty()) ||
context
.config
.max_width()
.checked_sub(result.len())
.unwrap_or(0) < overhead
{
format!("\n{}{{", offset.block_only().to_string(context.config))
} else {
" {".to_owned()
}
}
};
// 1 = `}`
let overhead = if fields.is_empty() { 1 } else { 0 };
let max_len = context
.config
.max_width()
.checked_sub(offset.width())
.unwrap_or(0);
if !generics_str.contains('\n') && result.len() + generics_str.len() + overhead > max_len {
result.push('\n');
result.push_str(&offset.to_string(context.config));
result.push_str(&generics_str.trim_left());
} else {
result.push_str(&generics_str);
}
if fields.is_empty() {
let snippet = context.snippet(mk_sp(body_lo, span.hi() - BytePos(1)));
if snippet.trim().is_empty() {
// `struct S {}`
} else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
// fix indent
result.push_str(&snippet.trim_right());
result.push('\n');
result.push_str(&offset.to_string(context.config));
} else {
result.push_str(&snippet);
}
result.push('}');
return Some(result);
}
// 3 = ` ` and ` }`
let one_line_budget = context
.config
.max_width()
.checked_sub(result.len() + 3 + offset.width())
.unwrap_or(0);
let one_line_budget =
one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
let items_str = try_opt!(rewrite_with_alignment(
fields,
context,
Shape::indented(offset, context.config),
mk_sp(body_lo, span.hi()),
one_line_budget,
));
if !items_str.contains('\n') && !result.contains('\n') && items_str.len() <= one_line_budget {
Some(format!("{} {} }}", result, items_str))
} else {
Some(format!(
"{}\n{}{}\n{}}}",
result,
offset
.block_indent(context.config)
.to_string(context.config),
items_str,
offset.to_string(context.config)
))
}
}
fn format_tuple_struct(
context: &RewriteContext,
item_name: &str,
ident: ast::Ident,
vis: &ast::Visibility,
fields: &[ast::StructField],
generics: Option<&ast::Generics>,
span: Span,
offset: Indent,
) -> Option<String> {
let mut result = String::with_capacity(1024);
let header_str = format_header(item_name, ident, vis);
result.push_str(&header_str);
let body_lo = if fields.is_empty() {
context.codemap.span_after(span, "(")
} else {
fields[0].span.lo()
};
let body_hi = if fields.is_empty() {
context.codemap.span_after(span, ")")
} else {
// This is a dirty hack to work around a missing `)` from the span of the last field.
let last_arg_span = fields[fields.len() - 1].span;
if context.snippet(last_arg_span).ends_with(")") {
last_arg_span.hi()
} else {
context
.codemap
.span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
}
};
let where_clause_str = match generics {
Some(generics) => {
let budget = context.budget(last_line_width(&header_str));
let shape = Shape::legacy(budget, offset);
let g_span = mk_sp(span.lo(), body_lo);
let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
result.push_str(&generics_str);
let where_budget = context.budget(last_line_width(&result));
let option = WhereClauseOption::new(true, false);
try_opt!(rewrite_where_clause(
context,
&generics.where_clause,
context.config.item_brace_style(),
Shape::legacy(where_budget, offset.block_only()),
Density::Compressed,
";",
None,
body_hi,
option,
))
}
None => "".to_owned(),
};
if fields.is_empty() {
// 3 = `();`
let used_width = last_line_used_width(&result, offset.width()) + 3;
if used_width > context.config.max_width() {
result.push('\n');
result.push_str(&offset
.block_indent(context.config)
.to_string(context.config))
}
result.push('(');
let snippet = context.snippet(mk_sp(body_lo, context.codemap.span_before(span, ")")));
if snippet.is_empty() {
// `struct S ()`
} else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
result.push_str(&snippet.trim_right());
result.push('\n');
result.push_str(&offset.to_string(context.config));
} else {
result.push_str(&snippet);
}
result.push(')');
} else {
// 3 = `();`
let body = try_opt!(
rewrite_call_inner(
context,
"",
&fields.iter().map(|field| field).collect::<Vec<_>>()[..],
span,
Shape::legacy(context.budget(last_line_width(&result) + 3), offset),
context.config.fn_call_width(),
false,
).ok()
);
result.push_str(&body);
}
if !where_clause_str.is_empty() && !where_clause_str.contains('\n') &&
(result.contains('\n') ||
offset.block_indent + result.len() + where_clause_str.len() + 1 >
context.config.max_width())
{
// We need to put the where clause on a new line, but we didn't
// know that earlier, so the where clause will not be indented properly.
result.push('\n');
result.push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
.to_string(context.config));
}
result.push_str(&where_clause_str);
Some(result)
}
pub fn rewrite_type_alias(
context: &RewriteContext,
indent: Indent,
ident: ast::Ident,
ty: &ast::Ty,
generics: &ast::Generics,
vis: &ast::Visibility,
span: Span,
) -> Option<String> {
let mut result = String::with_capacity(128);
result.push_str(&format_visibility(vis));
result.push_str("type ");
result.push_str(&ident.to_string());
// 2 = `= `
let shape = try_opt!(Shape::indented(indent + result.len(), context.config).sub_width(2));
let g_span = mk_sp(context.codemap.span_after(span, "type"), ty.span.lo());
let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
result.push_str(&generics_str);
let where_budget = try_opt!(
context
.config
.max_width()
.checked_sub(last_line_width(&result))
);
let option = WhereClauseOption::snuggled(&result);
let where_clause_str = try_opt!(rewrite_where_clause(
context,
&generics.where_clause,
context.config.item_brace_style(),
Shape::legacy(where_budget, indent),
context.config.where_density(),
"=",
Some(span.hi()),
generics.span.hi(),
option,
));
result.push_str(&where_clause_str);
if where_clause_str.is_empty() {
result.push_str(" = ");
} else {
result.push_str(&format!("\n{}= ", indent.to_string(context.config)));
}
let line_width = last_line_width(&result);
// This checked_sub may fail as the extra space after '=' is not taken into account
// In that case the budget is set to 0 which will make ty.rewrite retry on a new line
let budget = context
.config
.max_width()
.checked_sub(indent.width() + line_width + ";".len())
.unwrap_or(0);
let type_indent = indent + line_width;
// Try to fit the type on the same line
let ty_str = try_opt!(
ty.rewrite(context, Shape::legacy(budget, type_indent))
.or_else(|| {
// The line was too short, try to put the type on the next line
// Remove the space after '='
result.pop();
let type_indent = indent.block_indent(context.config);
result.push('\n');
result.push_str(&type_indent.to_string(context.config));
let budget = try_opt!(
context
.config
.max_width()
.checked_sub(type_indent.width() + ";".len())
);
ty.rewrite(context, Shape::legacy(budget, type_indent))
})
);
result.push_str(&ty_str);
result.push_str(";");
Some(result)
}
fn type_annotation_spacing(config: &Config) -> (&str, &str) {
(
if config.space_before_type_annotation() {
" "
} else {
""
},
if config.space_after_type_annotation_colon() {
" "
} else {
""
},
)
}
pub fn rewrite_struct_field_prefix(
context: &RewriteContext,
field: &ast::StructField,
) -> Option<String> {
let vis = format_visibility(&field.vis);
let type_annotation_spacing = type_annotation_spacing(context.config);
Some(match field.ident {
Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
None => format!("{}", vis),
})
}
fn rewrite_struct_field_type(
context: &RewriteContext,
last_line_width: usize,
field: &ast::StructField,
spacing: &str,
shape: Shape,
) -> Option<String> {
let ty_shape = try_opt!(shape.offset_left(last_line_width + spacing.len()));
field
.ty
.rewrite(context, ty_shape)
.map(|ty| format!("{}{}", spacing, ty))
}
impl Rewrite for ast::StructField {
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
rewrite_struct_field(context, self, shape, 0)
}
}
pub fn rewrite_struct_field(
context: &RewriteContext,
field: &ast::StructField,
shape: Shape,
lhs_max_width: usize,
) -> Option<String> {
if contains_skip(&field.attrs) {
let span = context.snippet(mk_sp(field.attrs[0].span.lo(), field.span.hi()));
return wrap_str(span, context.config.max_width(), shape);
}
let type_annotation_spacing = type_annotation_spacing(context.config);
let prefix = try_opt!(rewrite_struct_field_prefix(context, field));
let attrs_str = try_opt!(field.attrs.rewrite(context, shape));
let attrs_extendable = attrs_str.is_empty() ||
(context.config.attributes_on_same_line_as_field() && is_attributes_extendable(&attrs_str));
let missing_span = if field.attrs.is_empty() {
mk_sp(field.span.lo(), field.span.lo())
} else {
mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
};
let mut spacing = String::from(if field.ident.is_some() {
type_annotation_spacing.1
} else {
""
});
// Try to put everything on a single line.
let attr_prefix = try_opt!(combine_strs_with_missing_comments(
context,
&attrs_str,
&prefix,
missing_span,
shape,
attrs_extendable,
));
let overhead = last_line_width(&attr_prefix);
let lhs_offset = lhs_max_width.checked_sub(overhead).unwrap_or(0);
for _ in 0..lhs_offset {
spacing.push(' ');
}
// In this extreme case we will be missing a space betweeen an attribute and a field.
if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
spacing.push(' ');
}
let ty_rewritten = rewrite_struct_field_type(context, overhead, field, &spacing, shape);
if let Some(ref ty) = ty_rewritten {
if !ty.contains('\n') {
return Some(attr_prefix + &ty);
}
}
// We must use multiline.
let last_line_width = last_line_width(&prefix);
let ty_rewritten = rewrite_struct_field_type(context, last_line_width, field, &spacing, shape);
let type_offset = shape.indent.block_indent(context.config);
let rewrite_type_in_next_line = || {
field
.ty
.rewrite(context, Shape::indented(type_offset, context.config))
};
let field_str = match ty_rewritten {
// If we start from the next line and type fits in a single line, then do so.
Some(ref ty) => match rewrite_type_in_next_line() {
Some(ref new_ty) if !new_ty.contains('\n') => format!(
"{}\n{}{}",
prefix,
type_offset.to_string(&context.config),
&new_ty
),
_ => prefix + &ty,
},
_ => {
let ty = try_opt!(rewrite_type_in_next_line());
format!(
"{}\n{}{}",
prefix,
type_offset.to_string(&context.config),
&ty
)
}
};
combine_strs_with_missing_comments(
context,
&attrs_str,
&field_str,
missing_span,
shape,
attrs_extendable,
)
}
pub fn rewrite_static(
prefix: &str,
vis: &ast::Visibility,
ident: ast::Ident,
ty: &ast::Ty,
mutability: ast::Mutability,
expr_opt: Option<&ptr::P<ast::Expr>>,
offset: Indent,
span: Span,
context: &RewriteContext,
) -> Option<String> {
let colon = colon_spaces(
context.config.space_before_type_annotation(),
context.config.space_after_type_annotation_colon(),
);
let prefix = format!(
"{}{} {}{}{}",
format_visibility(vis),
prefix,
format_mutability(mutability),
ident,
colon,
);
// 2 = " =".len()
let ty_str = try_opt!(ty.rewrite(
context,
try_opt!(
Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)
),
));
if let Some(expr) = expr_opt {
let lhs = format!("{}{} =", prefix, ty_str);
// 1 = ;
let remaining_width = context.config.max_width() - offset.block_indent - 1;
rewrite_assign_rhs(
context,
lhs,
expr,
Shape::legacy(remaining_width, offset.block_only()),
).and_then(|res| {
recover_comment_removed(res, span, context, Shape::indented(offset, context.config))
})
.map(|s| if s.ends_with(';') { s } else { s + ";" })
} else {
Some(format!("{}{};", prefix, ty_str))
}
}
pub fn rewrite_associated_type(
ident: ast::Ident,
ty_opt: Option<&ptr::P<ast::Ty>>,
ty_param_bounds_opt: Option<&ast::TyParamBounds>,
context: &RewriteContext,
indent: Indent,
) -> Option<String> {
let prefix = format!("type {}", ident);
let type_bounds_str = if let Some(ty_param_bounds) = ty_param_bounds_opt {
// 2 = ": ".len()
let shape = try_opt!(Shape::indented(indent, context.config).offset_left(prefix.len() + 2));
let bounds: &[_] = ty_param_bounds;
let bound_str = try_opt!(
bounds
.iter()
.map(|ty_bound| ty_bound.rewrite(context, shape))
.collect::<Option<Vec<_>>>()
);
if bounds.len() > 0 {
format!(": {}", join_bounds(context, shape, &bound_str))
} else {
String::new()
}
} else {
String::new()
};
if let Some(ty) = ty_opt {
let ty_str = try_opt!(ty.rewrite(
context,
Shape::legacy(
context.config.max_width() - indent.block_indent - prefix.len() - 2,
indent.block_only(),
),
));
Some(format!("{}{} = {};", prefix, type_bounds_str, ty_str))
} else {
Some(format!("{}{};", prefix, type_bounds_str))
}
}
pub fn rewrite_associated_impl_type(
ident: ast::Ident,
defaultness: ast::Defaultness,
ty_opt: Option<&ptr::P<ast::Ty>>,
ty_param_bounds_opt: Option<&ast::TyParamBounds>,
context: &RewriteContext,
indent: Indent,
) -> Option<String> {
let result = try_opt!(rewrite_associated_type(
ident,
ty_opt,
ty_param_bounds_opt,
context,
indent,
));
match defaultness {
ast::Defaultness::Default => Some(format!("default {}", result)),
_ => Some(result),
}
}
impl Rewrite for ast::FunctionRetTy {
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
match *self {
ast::FunctionRetTy::Default(_) => Some(String::new()),
ast::FunctionRetTy::Ty(ref ty) => {
let inner_width = try_opt!(shape.width.checked_sub(3));
ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
.map(|r| format!("-> {}", r))
}
}
}
}
fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
match ty.node {
ast::TyKind::Infer => {
let original = context.snippet(ty.span);
original != "_"
}
_ => false,
}
}
impl Rewrite for ast::Arg {
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
if is_named_arg(self) {
let mut result = try_opt!(
self.pat
.rewrite(context, Shape::legacy(shape.width, shape.indent))
);
if !is_empty_infer(context, &*self.ty) {
if context.config.space_before_type_annotation() {
result.push_str(" ");
}
result.push_str(":");
if context.config.space_after_type_annotation_colon() {
result.push_str(" ");
}
let max_width = try_opt!(shape.width.checked_sub(result.len()));
let ty_str = try_opt!(self.ty.rewrite(
context,
Shape::legacy(max_width, shape.indent + result.len()),
));
result.push_str(&ty_str);
}
Some(result)
} else {
self.ty.rewrite(context, shape)
}
}
}
fn rewrite_explicit_self(
explicit_self: &ast::ExplicitSelf,
args: &[ast::Arg],
context: &RewriteContext,
) -> Option<String> {
match explicit_self.node {
ast::SelfKind::Region(lt, m) => {
let mut_str = format_mutability(m);
match lt {
Some(ref l) => {
let lifetime_str = try_opt!(l.rewrite(
context,
Shape::legacy(context.config.max_width(), Indent::empty()),
));
Some(format!("&{} {}self", lifetime_str, mut_str))
}
None => Some(format!("&{}self", mut_str)),
}
}
ast::SelfKind::Explicit(ref ty, _) => {
assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
let mutability = explicit_self_mutability(&args[0]);
let type_str = try_opt!(ty.rewrite(
context,
Shape::legacy(context.config.max_width(), Indent::empty()),
));
Some(format!(
"{}self: {}",
format_mutability(mutability),
type_str
))
}
ast::SelfKind::Value(_) => {
assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
let mutability = explicit_self_mutability(&args[0]);
Some(format!("{}self", format_mutability(mutability)))
}
}
}
// Hacky solution caused by absence of `Mutability` in `SelfValue` and
// `SelfExplicit` variants of `ast::ExplicitSelf_`.
fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
mutability
} else {
unreachable!()
}
}
pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
if is_named_arg(arg) {
arg.pat.span.lo()
} else {
arg.ty.span.lo()
}
}
pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
match arg.ty.node {
ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
_ => arg.ty.span.hi(),
}
}
pub fn is_named_arg(arg: &ast::Arg) -> bool {
if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
ident.node != symbol::keywords::Invalid.ident()
} else {
true
}
}
// Return type is (result, force_new_line_for_brace)
fn rewrite_fn_base(
context: &RewriteContext,
indent: Indent,
ident: ast::Ident,
fd: &ast::FnDecl,
generics: &ast::Generics,
unsafety: ast::Unsafety,
constness: ast::Constness,
defaultness: ast::Defaultness,
abi: abi::Abi,
vis: &ast::Visibility,
span: Span,
newline_brace: bool,
has_body: bool,
has_braces: bool,
) -> Option<(String, bool)> {
let mut force_new_line_for_brace = false;
let where_clause = &generics.where_clause;
let mut result = String::with_capacity(1024);
// Vis defaultness constness unsafety abi.
result.push_str(&*format_visibility(vis));
result.push_str(format_defaultness(defaultness));
result.push_str(format_constness(constness));
result.push_str(format_unsafety(unsafety));
if abi != abi::Abi::Rust {
result.push_str(&format_abi(abi, context.config.force_explicit_abi()));
}
// fn foo
result.push_str("fn ");
result.push_str(&ident.to_string());
// Generics.
let overhead = if has_braces && !newline_brace {
// 4 = `() {`
4
} else {
// 2 = `()`
2
};
let used_width = last_line_used_width(&result, indent.width());
let one_line_budget = context
.config
.max_width()
.checked_sub(used_width + overhead)
.unwrap_or(0);
let shape = Shape {
width: one_line_budget,
indent: indent,
offset: used_width,
};
let g_span = mk_sp(span.lo(), fd.output.span().lo());
let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
result.push_str(&generics_str);
let snuggle_angle_bracket = generics_str
.lines()
.last()
.map_or(false, |l| l.trim_left().len() == 1);
// Note that the width and indent don't really matter, we'll re-layout the
// return type later anyway.
let ret_str = try_opt!(
fd.output
.rewrite(&context, Shape::indented(indent, context.config))
);
let multi_line_ret_str = ret_str.contains('\n');
let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
// Args.
let (one_line_budget, multi_line_budget, mut arg_indent) = try_opt!(compute_budgets_for_args(
context,
&result,
indent,
ret_str_len,
newline_brace,
has_braces,
multi_line_ret_str,
));
debug!(
"rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
one_line_budget,
multi_line_budget,
arg_indent
);
// Check if vertical layout was forced.
if one_line_budget == 0 {
if snuggle_angle_bracket {
result.push('(');
} else {
if context.config.fn_args_paren_newline() {
result.push('\n');
result.push_str(&arg_indent.to_string(context.config));
if context.config.fn_args_layout() == IndentStyle::Visual {
arg_indent = arg_indent + 1; // extra space for `(`
}
result.push('(');
} else {
result.push_str("(");
if context.config.fn_args_layout() == IndentStyle::Visual {
result.push('\n');
result.push_str(&arg_indent.to_string(context.config));
}
}
}
} else {
result.push('(');
}
if context.config.spaces_within_parens() && fd.inputs.len() > 0 && result.ends_with('(') {
result.push(' ')
}
// A conservative estimation, to goal is to be over all parens in generics
let args_start = generics
.ty_params
.last()
.map_or(span.lo(), |tp| end_typaram(tp));
let args_end = if fd.inputs.is_empty() {
context
.codemap
.span_after(mk_sp(args_start, span.hi()), ")")
} else {
let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
context.codemap.span_after(last_span, ")")
};
let args_span = mk_sp(
context
.codemap
.span_after(mk_sp(args_start, span.hi()), "("),
args_end,
);
let arg_str = try_opt!(rewrite_args(
context,
&fd.inputs,
fd.get_self().as_ref(),
one_line_budget,
multi_line_budget,
indent,
arg_indent,
args_span,
fd.variadic,
generics_str.contains('\n'),
));
let put_args_in_block = match context.config.fn_args_layout() {
IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
_ => false,
} && !fd.inputs.is_empty();
let mut args_last_line_contains_comment = false;
if put_args_in_block {
arg_indent = indent.block_indent(context.config);
result.push('\n');
result.push_str(&arg_indent.to_string(context.config));
result.push_str(&arg_str);
result.push('\n');
result.push_str(&indent.to_string(context.config));
result.push(')');
} else {
result.push_str(&arg_str);
let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
// Put the closing brace on the next line if it overflows the max width.
// 1 = `)`
if fd.inputs.len() == 0 && used_width + 1 > context.config.max_width() {
result.push('\n');
}
if context.config.spaces_within_parens() && fd.inputs.len() > 0 {
result.push(' ')
}
// If the last line of args contains comment, we cannot put the closing paren
// on the same line.
if arg_str
.lines()
.last()
.map_or(false, |last_line| last_line.contains("//"))
{
args_last_line_contains_comment = true;
result.push('\n');
result.push_str(&arg_indent.to_string(context.config));
}
result.push(')');
}
// Return type.
if let ast::FunctionRetTy::Ty(..) = fd.output {
let ret_should_indent = match context.config.fn_args_layout() {
// If our args are block layout then we surely must have space.
IndentStyle::Block if put_args_in_block || fd.inputs.len() == 0 => false,
_ if args_last_line_contains_comment => false,
_ if result.contains('\n') || multi_line_ret_str => true,
_ => {
// If the return type would push over the max width, then put the return type on
// a new line. With the +1 for the signature length an additional space between
// the closing parenthesis of the argument and the arrow '->' is considered.
let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
// If there is no where clause, take into account the space after the return type
// and the brace.
if where_clause.predicates.is_empty() {
sig_length += 2;
}
sig_length > context.config.max_width()
}
};
let ret_indent = if ret_should_indent {
let indent = match context.config.fn_return_indent() {
ReturnIndent::WithWhereClause => indent + 4,
// Aligning with non-existent args looks silly.
_ if arg_str.is_empty() => {
force_new_line_for_brace = true;
indent + 4
}
// FIXME: we might want to check that using the arg indent
// doesn't blow our budget, and if it does, then fallback to
// the where clause indent.
_ => arg_indent,
};
result.push('\n');
result.push_str(&indent.to_string(context.config));
indent
} else {
result.push(' ');
Indent::new(indent.block_indent, last_line_width(&result))
};
if multi_line_ret_str || ret_should_indent {
// Now that we know the proper indent and width, we need to
// re-layout the return type.
let ret_str = try_opt!(
fd.output
.rewrite(context, Shape::indented(ret_indent, context.config))
);
result.push_str(&ret_str);
} else {
result.push_str(&ret_str);
}
// Comment between return type and the end of the decl.
let snippet_lo = fd.output.span().hi();
if where_clause.predicates.is_empty() {
let snippet_hi = span.hi();
let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
// Try to preserve the layout of the original snippet.
let original_starts_with_newline = snippet
.find(|c| c != ' ')
.map_or(false, |i| snippet[i..].starts_with('\n'));
let original_ends_with_newline = snippet
.rfind(|c| c != ' ')
.map_or(false, |i| snippet[i..].ends_with('\n'));
let snippet = snippet.trim();
if !snippet.is_empty() {
result.push(if original_starts_with_newline {
'\n'
} else {
' '
});
result.push_str(snippet);
if original_ends_with_newline {
force_new_line_for_brace = true;
}
}
}
}
let should_compress_where = match context.config.where_density() {
Density::Compressed => !result.contains('\n'),
Density::CompressedIfEmpty => !has_body && !result.contains('\n'),
_ => false,
};
let pos_before_where = match fd.output {
ast::FunctionRetTy::Default(..) => args_span.hi(),
ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
};
if where_clause.predicates.len() == 1 && should_compress_where {
let budget = context
.config
.max_width()
.checked_sub(last_line_used_width(&result, indent.width()))
.unwrap_or(0);
if let Some(where_clause_str) = rewrite_where_clause(
context,
where_clause,
context.config.fn_brace_style(),
Shape::legacy(budget, indent),
Density::Compressed,
"{",
Some(span.hi()),
pos_before_where,
WhereClauseOption::compressed(),
) {
result.push_str(&where_clause_str);
force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
return Some((result, force_new_line_for_brace));
}
}
let option = WhereClauseOption::new(!has_braces, put_args_in_block && ret_str.is_empty());
let where_clause_str = try_opt!(rewrite_where_clause(
context,
where_clause,
context.config.fn_brace_style(),
Shape::indented(indent, context.config),
Density::Tall,
"{",
Some(span.hi()),
pos_before_where,
option,
));
// If there are neither where clause nor return type, we may be missing comments between
// args and `{`.
if where_clause_str.is_empty() {
if let ast::FunctionRetTy::Default(ret_span) = fd.output {
match recover_missing_comment_in_span(
mk_sp(args_span.hi(), ret_span.hi()),
shape,
context,
last_line_width(&result),
) {
Some(ref missing_comment) if !missing_comment.is_empty() => {
result.push_str(missing_comment);
force_new_line_for_brace = true;
}
_ => (),
}
}
}
result.push_str(&where_clause_str);
force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
return Some((result, force_new_line_for_brace));
}
struct WhereClauseOption {
suppress_comma: bool, // Force no trailing comma
snuggle: bool, // Do not insert newline before `where`
compress_where: bool, // Try single line where clause instead of vertical layout
}
impl WhereClauseOption {
pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
WhereClauseOption {
suppress_comma: suppress_comma,
snuggle: snuggle,
compress_where: false,
}
}
pub fn compressed() -> WhereClauseOption {
WhereClauseOption {
suppress_comma: true,
snuggle: false,
compress_where: true,
}
}
pub fn snuggled(current: &str) -> WhereClauseOption {
WhereClauseOption {
suppress_comma: false,
snuggle: trimmed_last_line_width(current) == 1,
compress_where: false,
}
}
}
fn rewrite_args(
context: &RewriteContext,
args: &[ast::Arg],
explicit_self: Option<&ast::ExplicitSelf>,
one_line_budget: usize,
multi_line_budget: usize,
indent: Indent,
arg_indent: Indent,
span: Span,
variadic: bool,
generics_str_contains_newline: bool,
) -> Option<String> {
let mut arg_item_strs = try_opt!(
args.iter()
.map(|arg| {
arg.rewrite(&context, Shape::legacy(multi_line_budget, arg_indent))
})
.collect::<Option<Vec<_>>>()
);
// Account for sugary self.
// FIXME: the comment for the self argument is dropped. This is blocked
// on rust issue #27522.
let min_args = explicit_self
.and_then(|explicit_self| {
rewrite_explicit_self(explicit_self, args, context)
})
.map_or(1, |self_str| {
arg_item_strs[0] = self_str;
2
});
// Comments between args.
let mut arg_items = Vec::new();
if min_args == 2 {
arg_items.push(ListItem::from_str(""));
}
// FIXME(#21): if there are no args, there might still be a comment, but
// without spans for the comment or parens, there is no chance of
// getting it right. You also don't get to put a comment on self, unless
// it is explicit.
if args.len() >= min_args || variadic {
let comment_span_start = if min_args == 2 {
let second_arg_start = if arg_has_pattern(&args[1]) {
args[1].pat.span.lo()
} else {
args[1].ty.span.lo()
};
let reduced_span = mk_sp(span.lo(), second_arg_start);
context.codemap.span_after_last(reduced_span, ",")
} else {
span.lo()
};
enum ArgumentKind<'a> {
Regular(&'a ast::Arg),
Variadic(BytePos),
}
let variadic_arg = if variadic {
let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
let variadic_start = context.codemap.span_after(variadic_span, "...") - BytePos(3);
Some(ArgumentKind::Variadic(variadic_start))
} else {
None
};
let more_items = itemize_list(
context.codemap,
args[min_args - 1..]
.iter()
.map(ArgumentKind::Regular)
.chain(variadic_arg),
")",
|arg| match *arg {
ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
ArgumentKind::Variadic(start) => start,
},
|arg| match *arg {
ArgumentKind::Regular(arg) => arg.ty.span.hi(),
ArgumentKind::Variadic(start) => start + BytePos(3),
},
|arg| match *arg {
ArgumentKind::Regular(..) => None,
ArgumentKind::Variadic(..) => Some("...".to_owned()),
},
comment_span_start,
span.hi(),
false,
);
arg_items.extend(more_items);
}
let fits_in_one_line = !generics_str_contains_newline &&
(arg_items.len() == 0 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
item.item = Some(arg);
}
let last_line_ends_with_comment = arg_items
.iter()
.last()
.and_then(|item| item.post_comment.as_ref())
.map_or(false, |s| s.trim().starts_with("//"));
let (indent, trailing_comma) = match context.config.fn_args_layout() {
IndentStyle::Block if fits_in_one_line => {
(indent.block_indent(context.config), SeparatorTactic::Never)
}
IndentStyle::Block => (
indent.block_indent(context.config),
context.config.trailing_comma(),
),
IndentStyle::Visual if last_line_ends_with_comment => {
(arg_indent, context.config.trailing_comma())
}
IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
};
let tactic = definitive_tactic(
&arg_items,
context.config.fn_args_density().to_list_tactic(),
Separator::Comma,
one_line_budget,
);
let budget = match tactic {
DefinitiveListTactic::Horizontal => one_line_budget,
_ => multi_line_budget,
};
debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
let fmt = ListFormatting {
tactic: tactic,
separator: ",",
trailing_separator: if variadic {
SeparatorTactic::Never
} else {
trailing_comma
},
separator_place: SeparatorPlace::Back,
shape: Shape::legacy(budget, indent),
ends_with_newline: tactic.ends_with_newline(context.config.fn_args_layout()),
preserve_newline: true,
config: context.config,
};
write_list(&arg_items, &fmt)
}
fn arg_has_pattern(arg: &ast::Arg) -> bool {
if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
ident.node != symbol::keywords::Invalid.ident()
} else {
true
}
}
fn compute_budgets_for_args(
context: &RewriteContext,
result: &str,
indent: Indent,
ret_str_len: usize,
newline_brace: bool,
has_braces: bool,
force_vertical_layout: bool,
) -> Option<((usize, usize, Indent))> {
debug!(
"compute_budgets_for_args {} {:?}, {}, {}",
result.len(),
indent,
ret_str_len,
newline_brace
);
// Try keeping everything on the same line.
if !result.contains('\n') && !force_vertical_layout {
// 2 = `()`, 3 = `() `, space is before ret_string.
let overhead = if ret_str_len == 0 { 2 } else { 3 };
let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
if has_braces {
if !newline_brace {
// 2 = `{}`
used_space += 2;
}
} else {
// 1 = `;`
used_space += 1;
}
let one_line_budget = context
.config
.max_width()
.checked_sub(used_space)
.unwrap_or(0);
if one_line_budget > 0 {
// 4 = "() {".len()
let (indent, multi_line_budget) = match context.config.fn_args_layout() {
IndentStyle::Block => {
let indent = indent.block_indent(context.config);
let budget =
try_opt!(context.config.max_width().checked_sub(indent.width() + 1));
(indent, budget)
}
IndentStyle::Visual => {
let indent = indent + result.len() + 1;
let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
let budget =
try_opt!(context.config.max_width().checked_sub(multi_line_overhead));
(indent, budget)
}
};
return Some((one_line_budget, multi_line_budget, indent));
}
}
// Didn't work. we must force vertical layout and put args on a newline.
let new_indent = indent.block_indent(context.config);
let used_space = match context.config.fn_args_layout() {
// 1 = `,`
IndentStyle::Block => new_indent.width() + 1,
// Account for `)` and possibly ` {`.
IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
};
let max_space = try_opt!(context.config.max_width().checked_sub(used_space));
Some((0, max_space, new_indent))
}
fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause, has_body: bool) -> bool {
match (config.fn_brace_style(), config.where_density()) {
(BraceStyle::AlwaysNextLine, _) => true,
(_, Density::Compressed) if where_clause.predicates.len() == 1 => false,
(_, Density::CompressedIfEmpty) if where_clause.predicates.len() == 1 && !has_body => false,
(BraceStyle::SameLineWhere, _) if !where_clause.predicates.is_empty() => true,
_ => false,
}
}
fn rewrite_generics(
context: &RewriteContext,
generics: &ast::Generics,
shape: Shape,
span: Span,
) -> Option<String> {
let g_shape = try_opt!(generics_shape_from_config(context.config, shape, 0));
let one_line_width = shape.width.checked_sub(2).unwrap_or(0);
rewrite_generics_inner(context, generics, g_shape, one_line_width, span).or_else(|| {
rewrite_generics_inner(context, generics, g_shape, 0, span)
})
}
fn rewrite_generics_inner(
context: &RewriteContext,
generics: &ast::Generics,
shape: Shape,
one_line_width: usize,
span: Span,
) -> Option<String> {
// FIXME: convert bounds to where clauses where they get too big or if
// there is a where clause at all.
let lifetimes: &[_] = &generics.lifetimes;
let tys: &[_] = &generics.ty_params;
if lifetimes.is_empty() && tys.is_empty() {
return Some(String::new());
}
// Strings for the generics.
let lt_strs = lifetimes.iter().map(|lt| lt.rewrite(context, shape));
let ty_strs = tys.iter().map(|ty_param| ty_param.rewrite(context, shape));
// Extract comments between generics.
let lt_spans = lifetimes.iter().map(|l| {
let hi = if l.bounds.is_empty() {
l.lifetime.span.hi()
} else {
l.bounds[l.bounds.len() - 1].span.hi()
};
mk_sp(l.lifetime.span.lo(), hi)
});
let ty_spans = tys.iter().map(|ty| ty.span());
let items = itemize_list(
context.codemap,
lt_spans.chain(ty_spans).zip(lt_strs.chain(ty_strs)),
">",
|&(sp, _)| sp.lo(),
|&(sp, _)| sp.hi(),
// FIXME: don't clone
|&(_, ref str)| str.clone(),
context.codemap.span_after(span, "<"),
span.hi(),
false,
);
format_generics_item_list(context, items, shape, one_line_width)
}
pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
match config.generics_indent() {
IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
IndentStyle::Block => {
// 1 = ","
shape
.block()
.block_indent(config.tab_spaces())
.with_max_width(config)
.sub_width(1)
}
}
}
pub fn format_generics_item_list<I>(
context: &RewriteContext,
items: I,
shape: Shape,
one_line_budget: usize,
) -> Option<String>
where
I: Iterator<Item = ListItem>,
{
let item_vec = items.collect::<Vec<_>>();
let tactic = definitive_tactic(
&item_vec,
ListTactic::HorizontalVertical,
Separator::Comma,
one_line_budget,
);
let fmt = ListFormatting {
tactic: tactic,
separator: ",",
trailing_separator: if context.config.generics_indent() == IndentStyle::Visual {
SeparatorTactic::Never
} else {
context.config.trailing_comma()
},
separator_place: SeparatorPlace::Back,
shape: shape,
ends_with_newline: tactic.ends_with_newline(context.config.generics_indent()),
preserve_newline: true,
config: context.config,
};
let list_str = try_opt!(write_list(&item_vec, &fmt));
Some(wrap_generics_with_angle_brackets(
context,
&list_str,
shape.indent,
))
}
pub fn wrap_generics_with_angle_brackets(
context: &RewriteContext,
list_str: &str,
list_offset: Indent,
) -> String {
if context.config.generics_indent() == IndentStyle::Block &&
(list_str.contains('\n') || list_str.ends_with(','))
{
format!(
"<\n{}{}\n{}>",
list_offset.to_string(context.config),
list_str,
list_offset
.block_unindent(context.config)
.to_string(context.config)
)
} else if context.config.spaces_within_angle_brackets() {
format!("< {} >", list_str)
} else {
format!("<{}>", list_str)
}
}
fn rewrite_trait_bounds(
context: &RewriteContext,
type_param_bounds: &ast::TyParamBounds,
shape: Shape,
) -> Option<String> {
let bounds: &[_] = type_param_bounds;
if bounds.is_empty() {
return Some(String::new());
}
let bound_str = try_opt!(
bounds
.iter()
.map(|ty_bound| ty_bound.rewrite(&context, shape))
.collect::<Option<Vec<_>>>()
);
Some(format!(": {}", join_bounds(context, shape, &bound_str)))
}
fn rewrite_where_clause_rfc_style(
context: &RewriteContext,
where_clause: &ast::WhereClause,
shape: Shape,
terminator: &str,
span_end: Option<BytePos>,
span_end_before_where: BytePos,
where_clause_option: WhereClauseOption,
) -> Option<String> {
let block_shape = shape.block().with_max_width(context.config);
let (span_before, span_after) =
missing_span_before_after_where(span_end_before_where, where_clause);
let (comment_before, comment_after) = try_opt!(rewrite_comments_before_after_where(
context,
span_before,
span_after,
shape,
));
let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
" ".to_owned()
} else {
"\n".to_owned() + &block_shape.indent.to_string(context.config)
};
let clause_shape = block_shape.block_indent(context.config.tab_spaces());
// each clause on one line, trailing comma (except if suppress_comma)
let span_start = where_clause.predicates[0].span().lo();
// If we don't have the start of the next span, then use the end of the
// predicates, but that means we miss comments.
let len = where_clause.predicates.len();
let end_of_preds = where_clause.predicates[len - 1].span().hi();
let span_end = span_end.unwrap_or(end_of_preds);
let items = itemize_list(
context.codemap,
where_clause.predicates.iter(),
terminator,
|pred| pred.span().lo(),
|pred| pred.span().hi(),
|pred| pred.rewrite(context, block_shape),
span_start,
span_end,
false,
);
let comma_tactic = if where_clause_option.suppress_comma {
SeparatorTactic::Never
} else {
context.config.trailing_comma()
};
let fmt = ListFormatting {
tactic: DefinitiveListTactic::Vertical,
separator: ",",
trailing_separator: comma_tactic,
separator_place: SeparatorPlace::Back,
shape: clause_shape,
ends_with_newline: true,
preserve_newline: true,
config: context.config,
};
let preds_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
let comment_separator = |comment: &str, shape: Shape| if comment.is_empty() {
String::new()
} else {
format!("\n{}", shape.indent.to_string(context.config))
};
let newline_before_where = comment_separator(&comment_before, shape);
let newline_after_where = comment_separator(&comment_after, clause_shape);
// 6 = `where `
let clause_sep = if where_clause_option.compress_where && comment_before.is_empty() &&
comment_after.is_empty() && !preds_str.contains('\n') &&
6 + preds_str.len() <= shape.width
{
String::from(" ")
} else {
format!("\n{}", clause_shape.indent.to_string(context.config))
};
Some(format!(
"{}{}{}where{}{}{}{}",
starting_newline,
comment_before,
newline_before_where,
newline_after_where,
comment_after,
clause_sep,
preds_str
))
}
fn rewrite_where_clause(
context: &RewriteContext,
where_clause: &ast::WhereClause,
brace_style: BraceStyle,
shape: Shape,
density: Density,
terminator: &str,
span_end: Option<BytePos>,
span_end_before_where: BytePos,
where_clause_option: WhereClauseOption,
) -> Option<String> {
if where_clause.predicates.is_empty() {
return Some(String::new());
}
if context.config.where_style() == Style::Rfc {
return rewrite_where_clause_rfc_style(
context,
where_clause,
shape,
terminator,
span_end,
span_end_before_where,
where_clause_option,
);
}
let extra_indent = Indent::new(context.config.tab_spaces(), 0);
let offset = match context.config.where_pred_indent() {
IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
// 6 = "where ".len()
IndentStyle::Visual => shape.indent + extra_indent + 6,
};
// FIXME: if where_pred_indent != Visual, then the budgets below might
// be out by a char or two.
let budget = context.config.max_width() - offset.width();
let span_start = where_clause.predicates[0].span().lo();
// If we don't have the start of the next span, then use the end of the
// predicates, but that means we miss comments.
let len = where_clause.predicates.len();
let end_of_preds = where_clause.predicates[len - 1].span().hi();
let span_end = span_end.unwrap_or(end_of_preds);
let items = itemize_list(
context.codemap,
where_clause.predicates.iter(),
terminator,
|pred| pred.span().lo(),
|pred| pred.span().hi(),
|pred| pred.rewrite(context, Shape::legacy(budget, offset)),
span_start,
span_end,
false,
);
let item_vec = items.collect::<Vec<_>>();
// FIXME: we don't need to collect here if the where_layout isn't
// HorizontalVertical.
let tactic = definitive_tactic(
&item_vec,
context.config.where_layout(),
Separator::Comma,
budget,
);
let mut comma_tactic = context.config.trailing_comma();
// Kind of a hack because we don't usually have trailing commas in where clauses.
if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
comma_tactic = SeparatorTactic::Never;
}
let fmt = ListFormatting {
tactic: tactic,
separator: ",",
trailing_separator: comma_tactic,
separator_place: SeparatorPlace::Back,
shape: Shape::legacy(budget, offset),
ends_with_newline: tactic.ends_with_newline(context.config.where_pred_indent()),
preserve_newline: true,
config: context.config,
};
let preds_str = try_opt!(write_list(&item_vec, &fmt));
let end_length = if terminator == "{" {
// If the brace is on the next line we don't need to count it otherwise it needs two
// characters " {"
match brace_style {
BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
BraceStyle::PreferSameLine => 2,
}
} else if terminator == "=" {
2
} else {
terminator.len()
};
if density == Density::Tall || preds_str.contains('\n') ||
shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
{
Some(format!(
"\n{}where {}",
(shape.indent + extra_indent).to_string(context.config),
preds_str
))
} else {
Some(format!(" where {}", preds_str))
}
}
fn missing_span_before_after_where(
before_item_span_end: BytePos,
where_clause: &ast::WhereClause,
) -> (Span, Span) {
let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
// 5 = `where`
let pos_after_where = where_clause.span.lo() + BytePos(5);
let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
(missing_span_before, missing_span_after)
}
fn rewrite_comments_before_after_where(
context: &RewriteContext,
span_before_where: Span,
span_after_where: Span,
shape: Shape,
) -> Option<(String, String)> {
let before_comment = try_opt!(rewrite_missing_comment(span_before_where, shape, context));
let after_comment = try_opt!(rewrite_missing_comment(
span_after_where,
shape.block_indent(context.config.tab_spaces()),
context,
));
Some((before_comment, after_comment))
}
fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
format!("{}{}{}", format_visibility(vis), item_name, ident)
}
fn format_generics(
context: &RewriteContext,
generics: &ast::Generics,
opener: &str,
terminator: &str,
brace_style: BraceStyle,
force_same_line_brace: bool,
offset: Indent,
span: Span,
used_width: usize,
) -> Option<String> {
let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
let mut result = try_opt!(rewrite_generics(context, generics, shape, span));
let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
let budget = context
.config
.max_width()
.checked_sub(last_line_used_width(&result, offset.width()))
.unwrap_or(0);
let option = WhereClauseOption::snuggled(&result);
let where_clause_str = try_opt!(rewrite_where_clause(
context,
&generics.where_clause,
brace_style,
Shape::legacy(budget, offset.block_only()),
Density::Tall,
terminator,
Some(span.hi()),
generics.span.hi(),
option,
));
result.push_str(&where_clause_str);
force_same_line_brace || brace_style == BraceStyle::PreferSameLine ||
(generics.where_clause.predicates.is_empty() && trimmed_last_line_width(&result) == 1)
} else {
force_same_line_brace || trimmed_last_line_width(&result) == 1 ||
brace_style != BraceStyle::AlwaysNextLine
};
let total_used_width = last_line_used_width(&result, used_width);
let remaining_budget = context
.config
.max_width()
.checked_sub(total_used_width)
.unwrap_or(0);
// If the same line brace if forced, it indicates that we are rewriting an item with empty body,
// and hence we take the closer into account as well for one line budget.
// We assume that the closer has the same length as the opener.
let overhead = if force_same_line_brace {
1 + opener.len() + opener.len()
} else {
1 + opener.len()
};
let forbid_same_line_brace = overhead > remaining_budget;
if !forbid_same_line_brace && same_line_brace {
result.push(' ');
} else {
result.push('\n');
result.push_str(&offset.block_only().to_string(context.config));
}
result.push_str(opener);
Some(result)
}
impl Rewrite for ast::ForeignItem {
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
let attrs_str = try_opt!(self.attrs.rewrite(context, shape));
// Drop semicolon or it will be interpreted as comment.
// FIXME: this may be a faulty span from libsyntax.
let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
let item_str = try_opt!(match self.node {
ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
rewrite_fn_base(
context,
shape.indent,
self.ident,
fn_decl,
generics,
ast::Unsafety::Normal,
ast::Constness::NotConst,
ast::Defaultness::Final,
// These are not actually rust functions,
// but we format them as such.
abi::Abi::Rust,
&self.vis,
span,
false,
false,
false,
).map(|(s, _)| format!("{};", s))
}
ast::ForeignItemKind::Static(ref ty, is_mutable) => {
// FIXME(#21): we're dropping potential comments in between the
// function keywords here.
let vis = format_visibility(&self.vis);
let mut_str = if is_mutable { "mut " } else { "" };
let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
// 1 = ;
let shape = try_opt!(shape.sub_width(1));
ty.rewrite(context, shape).map(|ty_str| {
// 1 = space between prefix and type.
let sep = if prefix.len() + ty_str.len() + 1 <= shape.width {
String::from(" ")
} else {
let nested_indent = shape.indent.block_indent(context.config);
format!("\n{}", nested_indent.to_string(context.config))
};
format!("{}{}{};", prefix, sep, ty_str)
})
}
});
let missing_span = if self.attrs.is_empty() {
mk_sp(self.span.lo(), self.span.lo())
} else {
mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
};
combine_strs_with_missing_comments(
context,
&attrs_str,
&item_str,
missing_span,
shape,
false,
)
}
}