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Add failure mode to write_list

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This commit is contained in:
Marcus Klaas 2015-09-04 18:09:05 +02:00
parent 2a61a989d5
commit d05a41c773
12 changed files with 294 additions and 212 deletions
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117
src/expr.rs
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@ -8,11 +8,13 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::cmp::Ordering;
use rewrite::{Rewrite, RewriteContext};
use lists::{write_list, itemize_list, ListFormatting, SeparatorTactic, ListTactic};
use string::{StringFormat, rewrite_string};
use StructLitStyle;
use utils::{span_after, make_indent, extra_offset, first_line_width, last_line_width};
use utils::{span_after, make_indent, extra_offset, first_line_width, last_line_width, wrap_str};
use visitor::FmtVisitor;
use config::BlockIndentStyle;
use comment::{FindUncommented, rewrite_comment, contains_comment};
@ -134,37 +136,9 @@ impl Rewrite for ast::Expr {
ast::Expr_::ExprClosure(capture, ref fn_decl, ref body) => {
rewrite_closure(capture, fn_decl, body, self.span, context, width, offset)
}
_ => {
// We do not format these expressions yet, but they should still
// satisfy our width restrictions.
let snippet = context.snippet(self.span);
{
let mut lines = snippet.lines();
// The caller of this function has already placed `offset`
// characters on the first line.
let first_line_max_len = try_opt!(context.config.max_width.checked_sub(offset));
if lines.next().unwrap().len() > first_line_max_len {
return None;
}
// The other lines must fit within the maximum width.
if lines.find(|line| line.len() > context.config.max_width).is_some() {
return None;
}
// `width` is the maximum length of the last line, excluding
// indentation.
// A special check for the last line, since the caller may
// place trailing characters on this line.
if snippet.lines().rev().next().unwrap().len() > offset + width {
return None;
}
}
Some(snippet)
}
// We do not format these expressions yet, but they should still
// satisfy our width restrictions.
_ => wrap_str(context.snippet(self.span), context.config.max_width, width, offset),
}
}
}
@ -202,7 +176,8 @@ fn rewrite_closure(capture: ast::CaptureClause,
body.span.lo);
let fmt = ListFormatting::for_fn(argument_budget, argument_offset);
let prefix = format!("{}|{}|", mover, write_list(&arg_items.collect::<Vec<_>>(), &fmt));
let list_str = try_opt!(write_list(&arg_items.collect::<Vec<_>>(), &fmt));
let prefix = format!("{}|{}|", mover, list_str);
let closure_indent = closure_indent(context, offset);
// Try to format closure body as a single line expression without braces.
@ -869,19 +844,58 @@ fn rewrite_call(context: &RewriteContext,
-> Option<String> {
debug!("rewrite_call, width: {}, offset: {}", width, offset);
// FIXME using byte lens instead of char lens (and probably all over the place too)
// 2 is for parens
let max_callee_width = try_opt!(width.checked_sub(2));
let callee_str = try_opt!(callee.rewrite(context, max_callee_width, offset));
debug!("rewrite_call, callee_str: `{}`", callee_str);
let mut hi = try_opt!(width.checked_sub(2)) * 2;
let mut lo = 0;
let mut tries = 0;
if args.is_empty() {
return Some(format!("{}()", callee_str));
// Binary search for the best split between callee and arguments.
loop {
let middle = (lo + hi) / 2;
match rewrite_call_inner(context, callee, middle, args, span, width, offset) {
_ if tries > 10 => return None,
Ok(result) => return Some(result),
Err(Ordering::Less) => {
lo = middle;
tries += 1;
}
Err(Ordering::Greater) => {
hi = middle;
tries += 1;
}
_ => unreachable!(),
}
}
}
fn rewrite_call_inner(context: &RewriteContext,
callee: &ast::Expr,
max_callee_width: usize,
args: &[ptr::P<ast::Expr>],
span: Span,
width: usize,
offset: usize)
-> Result<String, Ordering> {
// FIXME using byte lens instead of char lens (and probably all over the place too)
let callee_str = match callee.rewrite(context, max_callee_width, offset) {
Some(string) => {
if !string.contains('\n') && string.len() > max_callee_width {
panic!("{:?} {}", string, max_callee_width);
} else {
string
}
}
None => return Err(Ordering::Less),
};
debug!("rewrite_call, callee_str: `{}`", callee_str);
let extra_offset = extra_offset(&callee_str, offset);
// 2 is for parens.
let remaining_width = try_opt!(width.checked_sub(extra_offset + 2));
let remaining_width = match width.checked_sub(extra_offset + 2) {
Some(str) => str,
None => return Err(Ordering::Greater),
};
let offset = offset + extra_offset + 1;
let inner_indent = expr_indent(context, offset);
let inner_context = context.overflow_context(inner_indent - context.block_indent);
@ -900,8 +914,12 @@ fn rewrite_call(context: &RewriteContext,
span.hi);
let fmt = ListFormatting::for_fn(remaining_width, offset);
let list_str = match write_list(&items.collect::<Vec<_>>(), &fmt) {
Some(str) => str,
None => return Err(Ordering::Greater),
};
Some(format!("{}({})", callee_str, write_list(&items.collect::<Vec<_>>(), &fmt)))
Ok(format!("{}({})", callee_str, list_str))
}
macro_rules! block_indent_helper {
@ -1024,7 +1042,7 @@ fn rewrite_struct_lit<'a>(context: &RewriteContext,
v_width: v_budget,
ends_with_newline: false,
};
let fields_str = write_list(&items.collect::<Vec<_>>(), &fmt);
let fields_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
match context.config.struct_lit_style {
StructLitStyle::Block if fields_str.contains('\n') => {
@ -1046,7 +1064,8 @@ fn rewrite_field(context: &RewriteContext,
-> Option<String> {
let name = &field.ident.node.to_string();
let overhead = name.len() + 2;
let expr = field.expr.rewrite(context, try_opt!(width.checked_sub(overhead)), offset + overhead);
let expr =
field.expr.rewrite(context, try_opt!(width.checked_sub(overhead)), offset + overhead);
expr.map(|s| format!("{}: {}", name, s))
}
@ -1080,8 +1099,9 @@ fn rewrite_tuple_lit(context: &RewriteContext,
let budget = try_opt!(width.checked_sub(2));
let fmt = ListFormatting::for_fn(budget, indent);
let list_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
Some(format!("({})", write_list(&items.collect::<Vec<_>>(), &fmt)))
Some(format!("({})", list_str))
}
fn rewrite_binary_op(context: &RewriteContext,
@ -1206,12 +1226,13 @@ pub fn rewrite_assign_rhs<S: Into<String>>(context: &RewriteContext,
let new_offset = offset + context.config.tab_spaces;
result.push_str(&format!("\n{}", make_indent(new_offset)));
// FIXME: we probably should related max_width to width instead of config.max_width
// where is the 1 coming from anyway?
let max_width = try_opt!(context.config.max_width.checked_sub(new_offset + 1));
let rhs = try_opt!(ex.rewrite(&context.overflow_context(context.config.tab_spaces),
max_width,
new_offset));
let overflow_context = context.overflow_context(context.config.tab_spaces);
let rhs = ex.rewrite(&overflow_context, max_width, new_offset);
result.push_str(&rhs);
result.push_str(&&try_opt!(rhs));
}
}