use config::IndentStyle;
use expr::rewrite_call;
use macros::convert_try_mac;
use rewrite::{Rewrite, RewriteContext};
use shape::Shape;
use utils::{
first_line_width, last_line_extendable, last_line_width, mk_sp, trimmed_last_line_width,
wrap_str,
};
use std::borrow::Cow;
use std::cmp::min;
use std::iter;
use syntax::codemap::Span;
use syntax::{ast, ptr};
pub fn rewrite_chain(expr: &ast::Expr, context: &RewriteContext, shape: Shape) -> Option<String> {
debug!("rewrite_chain {:?}", shape);
let total_span = expr.span;
let (parent, subexpr_list) = make_subexpr_list(expr, context);
if chain_only_try(&subexpr_list) {
return rewrite_try(&parent, subexpr_list.len(), context, shape);
}
let suffix_try_num = subexpr_list.iter().take_while(|e| is_try(e)).count();
let prefix_try_num = subexpr_list.iter().rev().take_while(|e| is_try(e)).count();
let parent_shape = if is_block_expr(context, &parent, "\n") {
match context.config.indent_style() {
IndentStyle::Visual => shape.visual_indent(0),
IndentStyle::Block => shape,
}
} else {
shape
};
let parent_rewrite = parent
.rewrite(context, parent_shape)
.map(|parent_rw| parent_rw + &"?".repeat(prefix_try_num))?;
let parent_rewrite_contains_newline = parent_rewrite.contains('\n');
let is_small_parent = shape.offset + parent_rewrite.len() <= context.config.tab_spaces();
let (nested_shape, extend) = if !parent_rewrite_contains_newline && is_continuable(&parent) {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
context.config.indent_style() == IndentStyle::Visual || is_small_parent,
)
} else if is_block_expr(context, &parent, &parent_rewrite) {
match context.config.indent_style() {
IndentStyle::Block => (parent_shape.block_indent(context.config.tab_spaces()), true),
IndentStyle::Visual => (parent_shape, false),
}
} else {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
false,
)
};
let other_child_shape = nested_shape.with_max_width(context.config);
let first_child_shape = if extend {
let overhead = last_line_width(&parent_rewrite);
let offset = trimmed_last_line_width(&parent_rewrite) + prefix_try_num;
match context.config.indent_style() {
IndentStyle::Visual => parent_shape.offset_left(overhead)?,
IndentStyle::Block => parent_shape.offset_left(offset)?,
}
} else {
other_child_shape
};
debug!(
"child_shapes {:?} {:?}",
first_child_shape, other_child_shape
);
let child_shape_iter = Some(first_child_shape)
.into_iter()
.chain(iter::repeat(other_child_shape));
let subexpr_num = subexpr_list.len();
let last_subexpr = &subexpr_list[suffix_try_num];
let subexpr_list = &subexpr_list[suffix_try_num..subexpr_num - prefix_try_num];
let iter = subexpr_list.iter().skip(1).rev().zip(child_shape_iter);
let mut rewrites = iter
.map(|(e, shape)| rewrite_chain_subexpr(e, total_span, context, shape))
.collect::<Option<Vec<_>>>()?;
let extend_last_subexpr = if is_small_parent {
rewrites.len() == 1 && last_line_extendable(&rewrites[0])
} else {
rewrites.is_empty() && last_line_extendable(&parent_rewrite)
};
let almost_total = if extend_last_subexpr {
last_line_width(&parent_rewrite)
} else {
rewrites.iter().fold(0, |a, b| a + b.len()) + parent_rewrite.len()
} + suffix_try_num;
let one_line_budget = if rewrites.is_empty() {
shape.width
} else {
min(shape.width, context.config.width_heuristics().chain_width)
};
let all_in_one_line = !parent_rewrite_contains_newline
&& rewrites.iter().all(|s| !s.contains('\n'))
&& almost_total < one_line_budget;
let last_shape = if rewrites.is_empty() {
first_child_shape
} else {
other_child_shape
}.sub_width(shape.rhs_overhead(context.config) + suffix_try_num)?;
let rewrite_last = || rewrite_chain_subexpr(last_subexpr, total_span, context, last_shape);
let (last_subexpr_str, fits_single_line) = if all_in_one_line || extend_last_subexpr {
parent_shape.offset_left(almost_total).map(|shape| {
if let Some(rw) = rewrite_chain_subexpr(last_subexpr, total_span, context, shape) {
let line_count = rw.lines().count();
let fits_single_line = almost_total + first_line_width(&rw) <= one_line_budget;
if fits_single_line && line_count >= 5 {
(Some(rw), true)
} else {
match rewrite_last() {
Some(ref new_rw) if !fits_single_line => (Some(new_rw.clone()), false),
Some(ref new_rw) if new_rw.lines().count() >= line_count => {
(Some(rw), fits_single_line)
}
new_rw @ Some(..) => (new_rw, false),
_ => (Some(rw), fits_single_line),
}
}
} else {
(rewrite_last(), false)
}
})?
} else {
(rewrite_last(), false)
};
rewrites.push(last_subexpr_str?);
let connector = if fits_single_line && !parent_rewrite_contains_newline {
Cow::from("")
} else {
if *context.force_one_line_chain.borrow() {
return None;
}
nested_shape.indent.to_string_with_newline(context.config)
};
let first_connector = if is_small_parent
|| fits_single_line
|| last_line_extendable(&parent_rewrite)
|| context.config.indent_style() == IndentStyle::Visual
{
""
} else {
&connector
};
let result = if is_small_parent && rewrites.len() > 1 {
let second_connector = if fits_single_line
|| rewrites[1] == "?"
|| last_line_extendable(&rewrites[0])
|| context.config.indent_style() == IndentStyle::Visual
{
""
} else {
&connector
};
format!(
"{}{}{}{}{}",
parent_rewrite,
first_connector,
rewrites[0],
second_connector,
join_rewrites(&rewrites[1..], &connector)
)
} else {
format!(
"{}{}{}",
parent_rewrite,
first_connector,
join_rewrites(&rewrites, &connector)
)
};
let result = format!("{}{}", result, "?".repeat(suffix_try_num));
if context.config.indent_style() == IndentStyle::Visual {
wrap_str(result, context.config.max_width(), shape)
} else {
Some(result)
}
}
fn chain_only_try(exprs: &[ast::Expr]) -> bool {
exprs.iter().all(|e| {
if let ast::ExprKind::Try(_) = e.node {
true
} else {
false
}
})
}
fn rewrite_try(
expr: &ast::Expr,
try_count: usize,
context: &RewriteContext,
shape: Shape,
) -> Option<String> {
let sub_expr = expr.rewrite(context, shape.sub_width(try_count)?)?;
Some(format!("{}{}", sub_expr, "?".repeat(try_count)))
}
fn join_rewrites(rewrites: &[String], connector: &str) -> String {
let mut rewrite_iter = rewrites.iter();
let mut result = rewrite_iter.next().unwrap().clone();
for rewrite in rewrite_iter {
if rewrite != "?" {
result.push_str(connector);
}
result.push_str(&rewrite);
}
result
}
fn is_block_expr(context: &RewriteContext, expr: &ast::Expr, repr: &str) -> bool {
match expr.node {
ast::ExprKind::Mac(..) | ast::ExprKind::Call(..) => {
context.use_block_indent() && repr.contains('\n')
}
ast::ExprKind::Struct(..)
| ast::ExprKind::While(..)
| ast::ExprKind::WhileLet(..)
| ast::ExprKind::If(..)
| ast::ExprKind::IfLet(..)
| ast::ExprKind::Block(..)
| ast::ExprKind::Loop(..)
| ast::ExprKind::ForLoop(..)
| ast::ExprKind::Match(..) => repr.contains('\n'),
ast::ExprKind::Paren(ref expr)
| ast::ExprKind::Binary(_, _, ref expr)
| ast::ExprKind::Index(_, ref expr)
| ast::ExprKind::Unary(_, ref expr) => is_block_expr(context, expr, repr),
_ => false,
}
}
fn make_subexpr_list(expr: &ast::Expr, context: &RewriteContext) -> (ast::Expr, Vec<ast::Expr>) {
let mut subexpr_list = vec![expr.clone()];
while let Some(subexpr) = pop_expr_chain(subexpr_list.last().unwrap(), context) {
subexpr_list.push(subexpr.clone());
}
let parent = subexpr_list.pop().unwrap();
(parent, subexpr_list)
}
fn chain_indent(context: &RewriteContext, shape: Shape) -> Shape {
match context.config.indent_style() {
IndentStyle::Visual => shape.visual_indent(0),
IndentStyle::Block => shape
.block_indent(context.config.tab_spaces())
.with_max_width(context.config),
}
}
fn pop_expr_chain(expr: &ast::Expr, context: &RewriteContext) -> Option<ast::Expr> {
match expr.node {
ast::ExprKind::MethodCall(_, ref expressions) => {
Some(convert_try(&expressions[0], context))
}
ast::ExprKind::Field(ref subexpr, _) | ast::ExprKind::Try(ref subexpr) => {
Some(convert_try(subexpr, context))
}
_ => None,
}
}
fn convert_try(expr: &ast::Expr, context: &RewriteContext) -> ast::Expr {
match expr.node {
ast::ExprKind::Mac(ref mac) if context.config.use_try_shorthand() => {
if let Some(subexpr) = convert_try_mac(mac, context) {
subexpr
} else {
expr.clone()
}
}
_ => expr.clone(),
}
}
fn rewrite_chain_subexpr(
expr: &ast::Expr,
span: Span,
context: &RewriteContext,
shape: Shape,
) -> Option<String> {
let rewrite_element = |expr_str: String| {
if expr_str.len() <= shape.width {
Some(expr_str)
} else {
None
}
};
match expr.node {
ast::ExprKind::MethodCall(ref segment, ref expressions) => {
let types = match segment.parameters {
Some(ref params) => match **params {
ast::PathParameters::AngleBracketed(ref data) => &data.types[..],
_ => &[],
},
_ => &[],
};
rewrite_method_call(segment.ident, types, expressions, span, context, shape)
}
ast::ExprKind::Field(ref nested, ref field) => {
let space = if is_tup_field_access(expr) && is_tup_field_access(nested) {
" "
} else {
""
};
rewrite_element(format!("{}.{}", space, field.name))
}
ast::ExprKind::Try(_) => rewrite_element(String::from("?")),
_ => unreachable!(),
}
}
fn is_tup_field_access(expr: &ast::Expr) -> bool {
match expr.node {
ast::ExprKind::Field(_, ref field) => {
field.name.to_string().chars().all(|c| c.is_digit(10))
}
_ => false,
}
}
fn is_continuable(expr: &ast::Expr) -> bool {
match expr.node {
ast::ExprKind::Path(..) => true,
_ => false,
}
}
fn is_try(expr: &ast::Expr) -> bool {
match expr.node {
ast::ExprKind::Try(..) => true,
_ => false,
}
}
fn rewrite_method_call(
method_name: ast::Ident,
types: &[ptr::P<ast::Ty>],
args: &[ptr::P<ast::Expr>],
span: Span,
context: &RewriteContext,
shape: Shape,
) -> Option<String> {
let (lo, type_str) = if types.is_empty() {
(args[0].span.hi(), String::new())
} else {
let type_list = types
.iter()
.map(|ty| ty.rewrite(context, shape))
.collect::<Option<Vec<_>>>()?;
let type_str = format!("::<{}>", type_list.join(", "));
(types.last().unwrap().span.hi(), type_str)
};
let callee_str = format!(".{}{}", method_name, type_str);
let span = mk_sp(lo, span.hi());
rewrite_call(context, &callee_str, &args[1..], span, shape)
}