// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use syntax::{ast, ptr};
-use syntax::codemap::Span;
+use config::lists::*;
use syntax::parse::classify;
+use syntax::source_map::Span;
+use syntax::{ast, ptr};
-use codemap::SpanUtils;
-use expr::{block_contains_comment, is_simple_block, is_unsafe_block, need_block_indent,
- rewrite_cond, ToExpr};
+use expr::{block_contains_comment, is_simple_block, is_unsafe_block, rewrite_cond};
use items::{span_hi_for_arg, span_lo_for_arg};
-use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting,
- ListTactic, Separator, SeparatorPlace, SeparatorTactic};
+use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, Separator};
+use overflow::OverflowableItem;
use rewrite::{Rewrite, RewriteContext};
use shape::Shape;
+use source_map::SpanUtils;
use utils::{last_line_width, left_most_sub_expr, stmt_expr};
-// This functions is pretty messy because of the rules around closures and blocks:
+// This module is pretty messy because of the rules around closures and blocks:
// FIXME - the below is probably no longer true in full.
// * if there is a return type, then there must be braces,
// * given a closure with braces, whether that is parsed to give an inner block
// * if the first expression in the body ends with a block (i.e., is a
// statement without needing a semi-colon), then adding or removing braces
// can change whether it is treated as an expression or statement.
+
pub fn rewrite_closure(
capture: ast::CaptureBy,
+ asyncness: ast::IsAsync,
+ movability: ast::Movability,
fn_decl: &ast::FnDecl,
body: &ast::Expr,
span: Span,
) -> Option<String> {
debug!("rewrite_closure {:?}", body);
- let (prefix, extra_offset) =
- rewrite_closure_fn_decl(capture, fn_decl, body, span, context, shape)?;
+ let (prefix, extra_offset) = rewrite_closure_fn_decl(
+ capture, asyncness, movability, fn_decl, body, span, context, shape,
+ )?;
// 1 = space between `|...|` and body.
let body_shape = shape.offset_left(extra_offset)?;
- if let ast::ExprKind::Block(ref block) = body.node {
+ if let ast::ExprKind::Block(ref block, _) = body.node {
// The body of the closure is an empty block.
- if block.stmts.is_empty() && !block_contains_comment(block, context.codemap) {
- return Some(format!("{} {{}}", prefix));
+ if block.stmts.is_empty() && !block_contains_comment(block, context.source_map) {
+ return body
+ .rewrite(context, shape)
+ .map(|s| format!("{} {}", prefix, s));
}
- let no_return_type = match fn_decl.output {
- ast::FunctionRetTy::Default(_) => true,
- _ => false,
- };
-
- // Figure out if the block is necessary.
- let needs_block = is_unsafe_block(block) || block.stmts.len() > 1 || context.inside_macro
- || block_contains_comment(block, context.codemap)
- || prefix.contains('\n');
-
- if no_return_type && !needs_block {
- // block.stmts.len() == 1
- if let Some(expr) = stmt_expr(&block.stmts[0]) {
- let result = if is_block_closure_forced(expr) {
- rewrite_closure_with_block(expr, &prefix, context, shape)
- } else {
- rewrite_closure_expr(expr, &prefix, context, body_shape)
- };
- if result.is_some() {
- return result;
- }
+ let result = match fn_decl.output {
+ ast::FunctionRetTy::Default(_) => {
+ try_rewrite_without_block(body, &prefix, context, shape, body_shape)
}
- }
+ _ => None,
+ };
- // Either we require a block, or tried without and failed.
- rewrite_closure_block(block, &prefix, context, body_shape)
+ result.or_else(|| {
+ // Either we require a block, or tried without and failed.
+ rewrite_closure_block(block, &prefix, context, body_shape)
+ })
} else {
rewrite_closure_expr(body, &prefix, context, body_shape).or_else(|| {
// The closure originally had a non-block expression, but we can't fit on
}
}
+fn try_rewrite_without_block(
+ expr: &ast::Expr,
+ prefix: &str,
+ context: &RewriteContext,
+ shape: Shape,
+ body_shape: Shape,
+) -> Option<String> {
+ let expr = get_inner_expr(expr, prefix, context);
+
+ if is_block_closure_forced(context, expr) {
+ rewrite_closure_with_block(expr, prefix, context, shape)
+ } else {
+ rewrite_closure_expr(expr, prefix, context, body_shape)
+ }
+}
+
+fn get_inner_expr<'a>(
+ expr: &'a ast::Expr,
+ prefix: &str,
+ context: &RewriteContext,
+) -> &'a ast::Expr {
+ if let ast::ExprKind::Block(ref block, _) = expr.node {
+ if !needs_block(block, prefix, context) {
+ // block.stmts.len() == 1
+ if let Some(expr) = stmt_expr(&block.stmts[0]) {
+ return get_inner_expr(expr, prefix, context);
+ }
+ }
+ }
+
+ expr
+}
+
+// Figure out if a block is necessary.
+fn needs_block(block: &ast::Block, prefix: &str, context: &RewriteContext) -> bool {
+ is_unsafe_block(block)
+ || block.stmts.len() > 1
+ || block_contains_comment(block, context.source_map)
+ || prefix.contains('\n')
+}
+
+fn veto_block(e: &ast::Expr) -> bool {
+ match e.node {
+ ast::ExprKind::Call(..)
+ | ast::ExprKind::Binary(..)
+ | ast::ExprKind::Cast(..)
+ | ast::ExprKind::Type(..)
+ | ast::ExprKind::Assign(..)
+ | ast::ExprKind::AssignOp(..)
+ | ast::ExprKind::Field(..)
+ | ast::ExprKind::Index(..)
+ | ast::ExprKind::Range(..)
+ | ast::ExprKind::Try(..) => true,
+ _ => false,
+ }
+}
+
// Rewrite closure with a single expression wrapping its body with block.
fn rewrite_closure_with_block(
body: &ast::Expr,
context: &RewriteContext,
shape: Shape,
) -> Option<String> {
+ let left_most = left_most_sub_expr(body);
+ let veto_block = veto_block(body) && !classify::expr_requires_semi_to_be_stmt(left_most);
+ if veto_block {
+ return None;
+ }
+
let block = ast::Block {
- stmts: vec![
- ast::Stmt {
- id: ast::NodeId::new(0),
- node: ast::StmtKind::Expr(ptr::P(body.clone())),
- span: body.span,
- },
- ],
+ stmts: vec![ast::Stmt {
+ id: ast::NodeId::new(0),
+ node: ast::StmtKind::Expr(ptr::P(body.clone())),
+ span: body.span,
+ }],
id: ast::NodeId::new(0),
rules: ast::BlockCheckMode::Default,
span: body.span,
+ recovered: false,
};
- rewrite_closure_block(&block, prefix, context, shape)
+ let block = ::expr::rewrite_block_with_visitor(context, "", &block, None, None, shape, false)?;
+ Some(format!("{} {}", prefix, block))
}
// Rewrite closure with a single expression without wrapping its body with block.
context: &RewriteContext,
shape: Shape,
) -> Option<String> {
- let mut rewrite = expr.rewrite(context, shape);
- if classify::expr_requires_semi_to_be_stmt(left_most_sub_expr(expr)) {
- rewrite = and_one_line(rewrite);
- }
- rewrite = rewrite.and_then(|rw| {
- if context.config.multiline_closure_forces_block() && rw.contains('\n') {
- None
- } else {
- Some(rw)
+ fn allow_multi_line(expr: &ast::Expr) -> bool {
+ match expr.node {
+ ast::ExprKind::Match(..)
+ | ast::ExprKind::Block(..)
+ | ast::ExprKind::TryBlock(..)
+ | ast::ExprKind::Loop(..)
+ | ast::ExprKind::Struct(..) => true,
+
+ ast::ExprKind::AddrOf(_, ref expr)
+ | ast::ExprKind::Box(ref expr)
+ | ast::ExprKind::Try(ref expr)
+ | ast::ExprKind::Unary(_, ref expr)
+ | ast::ExprKind::Cast(ref expr, _) => allow_multi_line(expr),
+
+ _ => false,
}
- });
- rewrite.map(|rw| format!("{} {}", prefix, rw))
+ }
+
+ // When rewriting closure's body without block, we require it to fit in a single line
+ // unless it is a block-like expression or we are inside macro call.
+ let veto_multiline = (!allow_multi_line(expr) && !context.inside_macro())
+ || context.config.force_multiline_blocks();
+ expr.rewrite(context, shape)
+ .and_then(|rw| {
+ if veto_multiline && rw.contains('\n') {
+ None
+ } else {
+ Some(rw)
+ }
+ })
+ .map(|rw| format!("{} {}", prefix, rw))
}
// Rewrite closure whose body is block.
context: &RewriteContext,
shape: Shape,
) -> Option<String> {
- // Start with visual indent, then fall back to block indent if the
- // closure is large.
- let block_threshold = context.config.closure_block_indent_threshold();
- if block_threshold >= 0 {
- if let Some(block_str) = block.rewrite(context, shape) {
- if block_str.matches('\n').count() <= block_threshold as usize
- && !need_block_indent(&block_str, shape)
- {
- return Some(format!("{} {}", prefix, block_str));
- }
- }
- }
-
- // The body of the closure is big enough to be block indented, that
- // means we must re-format.
- let block_shape = shape.block();
- let block_str = block.rewrite(context, block_shape)?;
- Some(format!("{} {}", prefix, block_str))
+ Some(format!("{} {}", prefix, block.rewrite(context, shape)?))
}
// Return type is (prefix, extra_offset)
fn rewrite_closure_fn_decl(
capture: ast::CaptureBy,
+ asyncness: ast::IsAsync,
+ movability: ast::Movability,
fn_decl: &ast::FnDecl,
body: &ast::Expr,
span: Span,
context: &RewriteContext,
shape: Shape,
) -> Option<(String, usize)> {
+ let is_async = if asyncness.is_async() { "async " } else { "" };
let mover = if capture == ast::CaptureBy::Value {
"move "
} else {
""
};
+ let immovable = if movability == ast::Movability::Static {
+ "static "
+ } else {
+ ""
+ };
// 4 = "|| {".len(), which is overconservative when the closure consists of
// a single expression.
- let nested_shape = shape.shrink_left(mover.len())?.sub_width(4)?;
+ let nested_shape = shape
+ .shrink_left(is_async.len() + mover.len() + immovable.len())?
+ .sub_width(4)?;
// 1 = |
let argument_offset = nested_shape.indent + 1;
let ret_str = fn_decl.output.rewrite(context, arg_shape)?;
let arg_items = itemize_list(
- context.codemap,
+ context.snippet_provider,
fn_decl.inputs.iter(),
"|",
+ ",",
|arg| span_lo_for_arg(arg),
|arg| span_hi_for_arg(context, arg),
|arg| arg.rewrite(context, arg_shape),
- context.codemap.span_after(span, "|"),
+ context.snippet_provider.span_after(span, "|"),
body.span.lo(),
false,
);
let item_vec = arg_items.collect::<Vec<_>>();
// 1 = space between arguments and return type.
- let horizontal_budget = nested_shape
- .width
- .checked_sub(ret_str.len() + 1)
- .unwrap_or(0);
+ let horizontal_budget = nested_shape.width.saturating_sub(ret_str.len() + 1);
let tactic = definitive_tactic(
&item_vec,
ListTactic::HorizontalVertical,
_ => arg_shape,
};
- let fmt = ListFormatting {
- tactic: tactic,
- separator: ",",
- trailing_separator: SeparatorTactic::Never,
- separator_place: SeparatorPlace::Back,
- shape: arg_shape,
- ends_with_newline: false,
- preserve_newline: true,
- config: context.config,
- };
+ let fmt = ListFormatting::new(arg_shape, context.config)
+ .tactic(tactic)
+ .preserve_newline(true);
let list_str = write_list(&item_vec, &fmt)?;
- let mut prefix = format!("{}|{}|", mover, list_str);
+ let mut prefix = format!("{}{}{}|{}|", is_async, immovable, mover, list_str);
if !ret_str.is_empty() {
if prefix.contains('\n') {
expr: &ast::Expr,
shape: Shape,
) -> Option<String> {
- if let ast::ExprKind::Closure(capture, ref fn_decl, ref body, _) = expr.node {
+ if let ast::ExprKind::Closure(capture, asyncness, movability, ref fn_decl, ref body, _) =
+ expr.node
+ {
let body = match body.node {
- ast::ExprKind::Block(ref block) if is_simple_block(block, context.codemap) => {
+ ast::ExprKind::Block(ref block, _)
+ if !is_unsafe_block(block)
+ && is_simple_block(block, Some(&body.attrs), context.source_map) =>
+ {
stmt_expr(&block.stmts[0]).unwrap_or(body)
}
_ => body,
};
- let (prefix, extra_offset) =
- rewrite_closure_fn_decl(capture, fn_decl, body, expr.span, context, shape)?;
+ let (prefix, extra_offset) = rewrite_closure_fn_decl(
+ capture, asyncness, movability, fn_decl, body, expr.span, context, shape,
+ )?;
// If the closure goes multi line before its body, do not overflow the closure.
if prefix.contains('\n') {
return None;
}
- // If we are inside macro, we do not want to add or remove block from closure body.
- if context.inside_macro {
- return expr.rewrite(context, shape);
- }
let body_shape = shape.offset_left(extra_offset)?;
// We force to use block for the body of the closure for certain kinds of expressions.
- if is_block_closure_forced(body) {
+ if is_block_closure_forced(context, body) {
return rewrite_closure_with_block(body, &prefix, context, body_shape).and_then(
|body_str| {
// If the expression can fit in a single line, we need not force block closure.
// When overflowing the closure which consists of a single control flow expression,
// force to use block if its condition uses multi line.
- let is_multi_lined_cond = rewrite_cond(context, body, body_shape)
- .map(|cond| cond.contains('\n') || cond.len() > body_shape.width)
- .unwrap_or(false);
+ let is_multi_lined_cond = rewrite_cond(context, body, body_shape).map_or(false, |cond| {
+ cond.contains('\n') || cond.len() > body_shape.width
+ });
if is_multi_lined_cond {
return rewrite_closure_with_block(body, &prefix, context, body_shape);
}
}
/// Returns true if the given vector of arguments has more than one `ast::ExprKind::Closure`.
-pub fn args_have_many_closure<T>(args: &[&T]) -> bool
-where
- T: ToExpr,
-{
+pub fn args_have_many_closure(args: &[OverflowableItem]) -> bool {
args.iter()
- .filter(|arg| {
- arg.to_expr()
- .map(|e| match e.node {
- ast::ExprKind::Closure(..) => true,
- _ => false,
- })
- .unwrap_or(false)
+ .filter_map(|arg| arg.to_expr())
+ .filter(|expr| match expr.node {
+ ast::ExprKind::Closure(..) => true,
+ _ => false,
})
- .count() > 1
+ .count()
+ > 1
}
-fn is_block_closure_forced(expr: &ast::Expr) -> bool {
- match expr.node {
- ast::ExprKind::If(..) |
- ast::ExprKind::IfLet(..) |
- ast::ExprKind::Loop(..) |
- ast::ExprKind::While(..) |
- ast::ExprKind::WhileLet(..) |
- ast::ExprKind::ForLoop(..) => true,
- ast::ExprKind::AddrOf(_, ref expr) |
- ast::ExprKind::Box(ref expr) |
- ast::ExprKind::Try(ref expr) |
- ast::ExprKind::Unary(_, ref expr) |
- ast::ExprKind::Cast(ref expr, _) => is_block_closure_forced(expr),
- _ => false,
+fn is_block_closure_forced(context: &RewriteContext, expr: &ast::Expr) -> bool {
+ // If we are inside macro, we do not want to add or remove block from closure body.
+ if context.inside_macro() {
+ false
+ } else {
+ is_block_closure_forced_inner(expr)
}
}
-fn and_one_line(x: Option<String>) -> Option<String> {
- x.and_then(|x| if x.contains('\n') { None } else { Some(x) })
+fn is_block_closure_forced_inner(expr: &ast::Expr) -> bool {
+ match expr.node {
+ ast::ExprKind::If(..)
+ | ast::ExprKind::IfLet(..)
+ | ast::ExprKind::While(..)
+ | ast::ExprKind::WhileLet(..)
+ | ast::ExprKind::ForLoop(..) => true,
+ ast::ExprKind::AddrOf(_, ref expr)
+ | ast::ExprKind::Box(ref expr)
+ | ast::ExprKind::Try(ref expr)
+ | ast::ExprKind::Unary(_, ref expr)
+ | ast::ExprKind::Cast(ref expr, _) => is_block_closure_forced_inner(expr),
+ _ => false,
+ }
}
projects / rust.git / blobdiff