Bug 1397439 - stylo: Use saturating subtraction for script level; r?emilio
MozReview-Commit-ID: 3OBc1f4k9Ru
new file mode 100644
--- /dev/null
+++ b/layout/style/crashtests/1397439-1.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<math>
+<mstyle scriptlevel=101>
+<mstyle scriptlevel=-204>
+</math>
+
--- a/layout/style/crashtests/crashtests.list
+++ b/layout/style/crashtests/crashtests.list
@@ -208,8 +208,9 @@ load 1393189.html
load 1393580.html
load 1389645.html
load 1390726.html
load 1393791.html
load 1384232.html
load 1395725.html
load 1396041.html
load 1397363-1.html
+load 1397439-1.html
--- a/servo/components/style/properties/gecko.mako.rs
+++ b/servo/components/style/properties/gecko.mako.rs
@@ -2355,17 +2355,17 @@ fn static_assert() {
/// unconstrained size are set to the explicit value. However, if the font
/// size is manually set to an em or percent unit, the unconstrained size
/// will be set to the value of that unit computed against the parent
/// unconstrained size, whereas the font size will be set computing against
/// the parent font size.
pub fn calculate_script_level_size(&self, parent: &Self, device: &Device) -> (Au, Au) {
use std::cmp;
- let delta = self.gecko.mScriptLevel - parent.gecko.mScriptLevel;
+ let delta = self.gecko.mScriptLevel.saturating_sub(parent.gecko.mScriptLevel);
let parent_size = Au(parent.gecko.mSize);
let parent_unconstrained_size = Au(parent.gecko.mScriptUnconstrainedSize);
if delta == 0 {
return (parent_size, parent_unconstrained_size)
}
