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Fix some potential arithmetic underflow issues

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There have been many of this sort already. These were just bugs waiting to happen.
This commit is contained in:
Marcus Klaas 2015-08-31 19:30:00 +02:00
parent a896d91ff6
commit 0f4bf9b3ba
1 changed files with 31 additions and 21 deletions
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52
src/expr.rs
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@ -219,7 +219,8 @@ fn rewrite_closure(capture: ast::CaptureClause,
// 1 = the separating space between arguments and the body.
let extra_offset = extra_offset(&prefix, offset) + 1;
let rewrite = inner_expr.rewrite(context, width - extra_offset, offset + extra_offset);
let budget = try_opt!(width.checked_sub(extra_offset));
let rewrite = inner_expr.rewrite(context, budget, offset + extra_offset);
// Checks if rewrite succeeded and fits on a single line.
let accept_rewrite = rewrite.as_ref().map(|result| !result.contains('\n')).unwrap_or(false);
@ -263,7 +264,8 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
if !trimmed.is_empty() {
// 9 = "unsafe {".len(), 7 = "unsafe ".len()
format!("unsafe {} ", rewrite_comment(trimmed, true, width - 9, offset + 7))
let budget = try_opt!(width.checked_sub(9));
format!("unsafe {} ", rewrite_comment(trimmed, true, budget, offset + 7))
} else {
"unsafe ".to_owned()
}
@ -357,7 +359,7 @@ impl<'a> Rewrite for Loop<'a> {
fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
let label_string = rewrite_label(self.label);
// 2 = " {".len()
let inner_width = width - self.keyword.len() - 2 - label_string.len();
let inner_width = try_opt!(width.checked_sub(self.keyword.len() + 2 + label_string.len()));
let inner_offset = offset + self.keyword.len() + label_string.len();
let pat_expr_string = match self.cond {
@ -393,14 +395,17 @@ fn rewrite_range(context: &RewriteContext,
offset: usize)
-> Option<String> {
let left_string = match left {
Some(expr) => try_opt!(expr.rewrite(context, width - 2, offset)),
Some(expr) => {
// 2 = ..
let max_width = try_opt!(width.checked_sub(2));
try_opt!(expr.rewrite(context, max_width, offset))
}
None => String::new(),
};
let right_string = match right {
Some(expr) => {
// 2 = ..
let max_width = (width - 2).checked_sub(left_string.len()).unwrap_or(0);
let max_width = try_opt!(width.checked_sub(left_string.len() + 2));
try_opt!(expr.rewrite(context, max_width, offset + 2 + left_string.len()))
}
None => String::new(),
@ -532,7 +537,8 @@ fn rewrite_match(context: &RewriteContext,
}
// `match `cond` {`
let cond_str = try_opt!(cond.rewrite(context, width - 8, offset + 6));
let cond_budget = try_opt!(width.checked_sub(8));
let cond_str = try_opt!(cond.rewrite(context, cond_budget, offset + 6));
let mut result = format!("match {} {{", cond_str);
let block_indent = context.block_indent;
@ -632,17 +638,20 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
};
// Patterns
let pat_strs = try_opt!(pats.iter().map(|p| p.rewrite(context,
// 5 = ` => {`
width - 5,
offset + context.config.tab_spaces))
// 5 = ` => {`
let pat_budget = try_opt!(width.checked_sub(5));
let pat_strs = try_opt!(pats.iter().map(|p| {
p.rewrite(context,
pat_budget,
offset + context.config.tab_spaces)
})
.collect::<Option<Vec<_>>>());
let mut total_width = pat_strs.iter().fold(0, |a, p| a + p.len());
// Add ` | `.len().
total_width += (pat_strs.len() - 1) * 3;
let mut vertical = total_width > width - 5 || pat_strs.iter().any(|p| p.contains('\n'));
let mut vertical = total_width > pat_budget || pat_strs.iter().any(|p| p.contains('\n'));
if !vertical {
// If the patterns were previously stacked, keep them stacked.
// FIXME should be an option.
@ -710,9 +719,8 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
return None;
}
let body_str = try_opt!(body.rewrite(context,
width - context.config.tab_spaces,
nested_indent));
let body_budget = try_opt!(width.checked_sub(context.config.tab_spaces));
let body_str = try_opt!(body.rewrite(context, body_budget, nested_indent));
Some(format!("{}{} =>\n{}{},",
attr_str.trim_left(),
pats_str,
@ -775,9 +783,8 @@ fn rewrite_pat_expr(context: &RewriteContext,
let pat_offset = offset + matcher.len();
let mut result = match pat {
Some(pat) => {
let pat_string = try_opt!(pat.rewrite(context,
width - connector.len() - matcher.len(),
pat_offset));
let pat_budget = try_opt!(width.checked_sub(connector.len() + matcher.len()));
let pat_string = try_opt!(pat.rewrite(context, pat_budget, pat_offset));
format!("{}{}{}", matcher, pat_string, connector)
}
None => String::new(),
@ -930,7 +937,8 @@ enum StructLitField<'a> {
}
// 2 = " {".len()
let path_str = try_opt!(path.rewrite(context, width - 2, offset));
let path_budget = try_opt!(width.checked_sub(2));
let path_str = try_opt!(path.rewrite(context, path_budget, offset));
// Foo { a: Foo } - indent is +3, width is -5.
let h_budget = try_opt!(width.checked_sub(path_str.len() + 5));
@ -1041,7 +1049,8 @@ fn rewrite_tuple_lit(context: &RewriteContext,
// In case of length 1, need a trailing comma
if items.len() == 1 {
// 3 = "(" + ",)"
return items[0].rewrite(context, width - 3, indent).map(|s| format!("({},)", s));
let budget = try_opt!(width.checked_sub(3));
return items[0].rewrite(context, budget, indent).map(|s| format!("({},)", s));
}
let items = itemize_list(context.codemap,
@ -1057,7 +1066,8 @@ fn rewrite_tuple_lit(context: &RewriteContext,
span.lo + BytePos(1), // Remove parens
span.hi - BytePos(1));
let fmt = ListFormatting::for_fn(width - 2, indent);
let budget = try_opt!(width.checked_sub(2));
let fmt = ListFormatting::for_fn(budget, indent);
Some(format!("({})", write_list(&items.collect::<Vec<_>>(), &fmt)))
}