use rewrite::{Rewrite, RewriteContext};
use shape::Shape;
use spanned::Spanned;
-use utils::{
- first_line_width, last_line_extendable, last_line_width, mk_sp, trimmed_last_line_width,
- wrap_str,
-};
+use utils::{first_line_width, last_line_extendable, last_line_width, mk_sp, wrap_str};
use std::borrow::Cow;
use std::cmp::min;
}
// An expression plus trailing `?`s to be formatted together.
+#[derive(Debug)]
struct ChainItem {
expr: ast::Expr,
tries: usize,
}
+#[derive(Debug)]
struct Chain {
parent: ChainItem,
// TODO do we need to clone the exprs?
}
Chain {
- parent: children.pop().unwrap(),
- children: children.into_iter().rev().collect(),
+ parent: children.remove(0),
+ children,
}
}
}
-fn rewrite_chain_block(mut chain: Chain, context: &RewriteContext, shape: Shape) -> Option<String> {
- let last = chain.children.pop().unwrap();
-
+fn rewrite_chain_block(chain: Chain, context: &RewriteContext, shape: Shape) -> Option<String> {
+ debug!("rewrite_chain_block {:?} {:?}", chain, shape);
// Parent is the first item in the chain, e.g., `foo` in `foo.bar.baz()`.
- let parent_rewrite = chain.parent.expr
+ // Root is the parent plus any other chain items placed on the first line to
+ // avoid an orphan. E.g.,
+ // ```
+ // foo.bar
+ // .baz()
+ // ```
+ // If `bar` were not part of the root, then baz would be orphaned and 'float'.
+ let mut root_rewrite = chain.parent.expr
.rewrite(context, shape)
.map(|parent_rw| parent_rw + &"?".repeat(chain.parent.tries))?;
- let parent_rewrite_contains_newline = parent_rewrite.contains('\n');
- let is_small_parent = shape.offset + parent_rewrite.len() <= context.config.tab_spaces();
- let parent_is_block = is_block_expr(context, &chain.parent.expr, &parent_rewrite);
- // Decide how to layout the rest of the chain. `extend` is true if we can
- // put the first non-parent item on the same line as the parent.
- let other_child_shape = if parent_is_block {
+ let mut children: &[_] = &chain.children;
+ let mut root_ends_with_block = is_block_expr(context, &chain.parent.expr, &root_rewrite);
+ let tab_width = context.config.tab_spaces().saturating_sub(shape.offset);
+
+ while root_rewrite.len() <= tab_width && !root_rewrite.contains('\n') {
+ let item = &children[0];
+ let shape = shape.offset_left(root_rewrite.len())?;
+ match rewrite_chain_subexpr(&item.expr, context, shape) {
+ Some(rewrite) => {
+ root_rewrite.push_str(&rewrite);
+ root_rewrite.push_str(&"?".repeat(item.tries));
+ }
+ None => break,
+ }
+
+ root_ends_with_block = is_block_expr(context, &item.expr, &root_rewrite);
+
+ children = &children[1..];
+ if children.is_empty() {
+ return Some(root_rewrite);
+ }
+ }
+
+ // Separate out the last item in the chain for special treatment below.
+ let last = &children[children.len() - 1];
+ children = &children[..children.len() - 1];
+
+ // Decide how to layout the rest of the chain.
+ let child_shape = if root_ends_with_block {
shape
} else {
shape.block_indent(context.config.tab_spaces())
}.with_max_width(context.config);
- let extend = parent_is_block || (is_small_parent && !parent_rewrite_contains_newline && is_continuable(&chain.parent.expr));
-
- let first_child_shape = if extend {
- let offset = trimmed_last_line_width(&parent_rewrite) + chain.parent.tries;
- other_child_shape.offset_left(offset)?
- } else {
- other_child_shape
- };
- debug!(
- "child_shapes {:?} {:?}",
- first_child_shape, other_child_shape
- );
-
- let mut rewrites: Vec<String> = Vec::with_capacity(chain.children.len());
- let mut is_block_like = Vec::with_capacity(chain.children.len());
- is_block_like.push(true);
- for (i, item) in chain.children.iter().enumerate() {
- let shape = if *is_block_like.last().unwrap() && !(extend && i == 0) {
- first_child_shape
- } else {
- other_child_shape
- };
- let rewrite = rewrite_chain_subexpr(&item.expr, context, shape)?;
+ let mut rewrites: Vec<String> = Vec::with_capacity(children.len());
+ rewrites.push(root_rewrite);
+ let mut is_block_like = Vec::with_capacity(children.len());
+ is_block_like.push(root_ends_with_block);
+ for item in children {
+ let rewrite = rewrite_chain_subexpr(&item.expr, context, child_shape)?;
is_block_like.push(is_block_expr(context, &item.expr, &rewrite));
rewrites.push(format!("{}{}", rewrite, "?".repeat(item.tries)));
}
// Total of all items excluding the last.
- 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 extend_last_subexpr = last_line_extendable(&rewrites[rewrites.len() - 1]);
let almost_total = if extend_last_subexpr {
- last_line_width(&parent_rewrite)
+ last_line_width(&rewrites[rewrites.len() - 1])
} else {
- rewrites.iter().fold(0, |a, b| a + b.len()) + parent_rewrite.len()
+ rewrites.iter().fold(0, |a, b| a + b.len())
} + last.tries;
- let one_line_budget = if rewrites.is_empty() {
+ let one_line_budget = if rewrites.len() == 1 {
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'))
+ let all_in_one_line = rewrites.iter().all(|s| !s.contains('\n'))
&& almost_total < one_line_budget;
- let last_shape = if is_block_like[rewrites.len()] {
- first_child_shape
+ let last_shape = if all_in_one_line {
+ shape.sub_width(last.tries)?
} else {
- other_child_shape
- }.sub_width(shape.rhs_overhead(context.config) + last.tries)?;
+ child_shape.sub_width(shape.rhs_overhead(context.config) + last.tries)?
+ };
// Rewrite the last child. The last child of a chain requires special treatment. We need to
// know whether 'overflowing' the last child make a better formatting:
// })
// ```
- // `rewrite_last` rewrites the last child on its own line. We use a closure here instead of
- // directly calling `rewrite_chain_subexpr()` to avoid exponential blowup.
- let (last_subexpr_str, fits_single_line) = if all_in_one_line || extend_last_subexpr {
+ let mut last_subexpr_str = None;
+ let mut fits_single_line = false;
+ if all_in_one_line || extend_last_subexpr {
// First we try to 'overflow' the last child and see if it looks better than using
// vertical layout.
- shape.offset_left(almost_total).map(|shape| {
+ if let Some(shape) = last_shape.offset_left(almost_total) {
if let Some(rw) = rewrite_chain_subexpr(&last.expr, context, shape) {
// We allow overflowing here only if both of the following conditions match:
// 1. The entire chain fits in a single line except the last child.
// 2. `last_child_str.lines().count() >= 5`.
let line_count = rw.lines().count();
- let fits_single_line = almost_total + first_line_width(&rw) <= one_line_budget;
+ let could_fit_single_line = almost_total + first_line_width(&rw) <= one_line_budget;
if fits_single_line && line_count >= 5 {
- (Some(rw), true)
+ last_subexpr_str = Some(rw);
+ fits_single_line = true;
} else {
// We could not know whether overflowing is better than using vertical layout,
// just by looking at the overflowed rewrite. Now we rewrite the last child
// on its own line, and compare two rewrites to choose which is better.
match rewrite_chain_subexpr(&last.expr, context, last_shape) {
- Some(ref new_rw) if !fits_single_line => (Some(new_rw.clone()), false),
+ Some(ref new_rw) if !could_fit_single_line => {
+ last_subexpr_str = Some(new_rw.clone());
+ }
Some(ref new_rw) if new_rw.lines().count() >= line_count => {
- (Some(rw), fits_single_line)
+ last_subexpr_str = Some(rw);
+ fits_single_line = could_fit_single_line;
+ }
+ new_rw @ Some(..) => {
+ last_subexpr_str = new_rw;
+ }
+ _ => {
+ last_subexpr_str = Some(rw);
+ fits_single_line = could_fit_single_line;
}
- new_rw @ Some(..) => (new_rw, false),
- _ => (Some(rw), fits_single_line),
}
}
- } else {
- (rewrite_chain_subexpr(&last.expr, context, last_shape), false)
}
- })?
- } else {
- (rewrite_chain_subexpr(&last.expr, context, last_shape), false)
- };
- rewrites.push(last_subexpr_str?);
+ }
+ }
+
+ last_subexpr_str = last_subexpr_str.or_else(|| rewrite_chain_subexpr(&last.expr, context, last_shape));
+ rewrites.push(format!("{}{}", last_subexpr_str?, "?".repeat(last.tries)));
+
// We should never look at this, since we only look at the block-ness of the
// previous item in the chain.
is_block_like.push(false);
- let connector = if fits_single_line && !parent_rewrite_contains_newline {
+ let connector = if fits_single_line && all_in_one_line {
// Yay, we can put everything on one line.
Cow::from("")
} else {
if *context.force_one_line_chain.borrow() {
return None;
}
- other_child_shape.indent.to_string_with_newline(context.config)
+ child_shape.indent.to_string_with_newline(context.config)
};
- let first_connector = if is_small_parent
- || fits_single_line
- || last_line_extendable(&parent_rewrite)
- {
- ""
- } 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])
- {
- ""
- } else {
- &connector
- };
- format!(
- "{}{}{}{}{}",
- parent_rewrite,
- first_connector,
- rewrites[0],
- second_connector,
- join_rewrites(&rewrites[1..], &is_block_like[2..], &connector),
- )
- } else {
- format!(
- "{}{}{}",
- parent_rewrite,
- first_connector,
- join_rewrites(&rewrites, &is_block_like[1..], &connector),
- )
- };
- let result = format!("{}{}", result, "?".repeat(last.tries));
+ let result = join_rewrites(&rewrites, &is_block_like, &connector);
Some(result)
}
let mut last_subexpr_str = None;
let mut fits_single_line = false;
-
if all_in_one_line {
// First we try to 'overflow' the last child and see if it looks better than using
// vertical layout.
// parens, braces, and brackets in its idiomatic formatting.
fn is_block_expr(context: &RewriteContext, expr: &ast::Expr, repr: &str) -> bool {
match expr.node {
- ast::ExprKind::Mac(..) | ast::ExprKind::Call(..) => {
+ ast::ExprKind::Mac(..)
+ | ast::ExprKind::Call(..)
+ | ast::ExprKind::MethodCall(..) => {
context.use_block_indent() && repr.contains('\n')
}
ast::ExprKind::Struct(..)
| ast::ExprKind::Binary(_, _, ref expr)
| ast::ExprKind::Index(_, ref expr)
| ast::ExprKind::Unary(_, ref expr)
- | ast::ExprKind::Closure(_, _, _, _, ref expr, _) => is_block_expr(context, expr, repr),
- ast::ExprKind::MethodCall(_, ref exprs) => {
- // TODO maybe should be like Call
- is_block_expr(context, exprs.last().unwrap(), repr)
- }
+ | ast::ExprKind::Closure(_, _, _, _, ref expr, _)
+ | ast::ExprKind::Try(ref expr)
+ | ast::ExprKind::Yield(Some(ref expr)) => is_block_expr(context, expr, repr),
_ => false,
}
}
projects / rust.git / commitdiff