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chains: more refactoring of visual formatting

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This commit is contained in:
Nick Cameron 2018-07-10 15:14:44 +12:00
parent 92701552bc
commit 86314bf09f
1 changed files with 33 additions and 41 deletions
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74
src/chains.rs
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@ -189,9 +189,9 @@ fn rewrite_chain_block(chain: Chain, context: &RewriteContext, shape: Shape) ->
shape.block_indent(context.config.tab_spaces())
}.with_max_width(context.config);
let mut rewrites: Vec<String> = Vec::with_capacity(children.len());
let mut rewrites: Vec<String> = Vec::with_capacity(children.len() + 2);
rewrites.push(root_rewrite);
let mut is_block_like = Vec::with_capacity(children.len());
let mut is_block_like = Vec::with_capacity(children.len() + 2);
is_block_like.push(root_ends_with_block);
for item in children {
let rewrite = rewrite_chain_subexpr(&item.expr, context, child_shape)?;
@ -314,60 +314,53 @@ fn rewrite_chain_block(chain: Chain, context: &RewriteContext, shape: Shape) ->
Some(result)
}
fn rewrite_chain_visual(mut chain: Chain, context: &RewriteContext, shape: Shape) -> Option<String> {
let last = chain.children.pop().unwrap();
fn rewrite_chain_visual(chain: Chain, context: &RewriteContext, shape: Shape) -> Option<String> {
// Parent is the first item in the chain, e.g., `foo` in `foo.bar.baz()`.
let parent_shape = if is_block_expr(context, &chain.parent.expr, "\n") {
shape.visual_indent(0)
} else {
shape
};
let parent_rewrite = chain.parent.expr
let mut children: &[_] = &chain.children;
let mut root_rewrite = chain.parent.expr
.rewrite(context, parent_shape)
.map(|parent_rw| parent_rw + &"?".repeat(chain.parent.tries))?;
let parent_rewrite_contains_newline = parent_rewrite.contains('\n');
let other_child_shape = shape.visual_indent(0).with_max_width(context.config);
// 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 extend = !parent_rewrite_contains_newline && is_continuable(&chain.parent.expr);
let first_child_shape = if extend {
let overhead = last_line_width(&parent_rewrite);
parent_shape.offset_left(overhead)?
} else {
other_child_shape
};
debug!(
"child_shapes {:?} {:?}",
first_child_shape, other_child_shape
);
let mut rewrites: Vec<String> = Vec::with_capacity(chain.children.len());
for (i, item) in chain.children.iter().enumerate() {
let shape = if i == 0 {
first_child_shape
} else {
other_child_shape
};
if !root_rewrite.contains('\n') && is_continuable(&chain.parent.expr) {
let item = &children[0];
let overhead = last_line_width(&root_rewrite);
let shape = parent_shape.offset_left(overhead)?;
let rewrite = rewrite_chain_subexpr(&item.expr, context, shape)?;
root_rewrite.push_str(&rewrite);
root_rewrite.push_str(&"?".repeat(item.tries));
children = &children[1..];
if children.is_empty() {
return Some(root_rewrite);
}
}
let last = &children[children.len() - 1];
children = &children[..children.len() - 1];
let child_shape = shape.visual_indent(0).with_max_width(context.config);
let mut rewrites: Vec<String> = Vec::with_capacity(children.len() + 2);
rewrites.push(root_rewrite);
for item in chain.children.iter() {
let rewrite = rewrite_chain_subexpr(&item.expr, context, child_shape)?;
rewrites.push(format!("{}{}", rewrite, "?".repeat(item.tries)));
}
// Total of all items excluding the last.
let almost_total = rewrites.iter().fold(0, |a, b| a + b.len()) + parent_rewrite.len() + last.tries;
let one_line_budget = if rewrites.is_empty() {
let almost_total = rewrites.iter().fold(0, |a, b| a + b.len()) + last.tries;
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 =
other_child_shape.sub_width(shape.rhs_overhead(context.config) + last.tries)?;
let last_shape = 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:
@ -445,7 +438,7 @@ fn rewrite_chain_visual(mut chain: Chain, context: &RewriteContext, shape: Shape
last_subexpr_str = last_subexpr_str.or_else(|| rewrite_chain_subexpr(&last.expr, context, last_shape));
rewrites.push(last_subexpr_str?);
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 {
@ -453,11 +446,10 @@ fn rewrite_chain_visual(mut chain: Chain, context: &RewriteContext, shape: Shape
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 result = format!("{}{}{}",
parent_rewrite,
let result = format!("{}{}",
join_rewrites_vis(&rewrites, &connector),
"?".repeat(last.tries),
);