Comments and minor fixes

3 files changed, 13 insertions, 6 deletions

diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 21d43c0d009..a7e433642c9 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -3202,8 +3202,7 @@ fn static_assert() {
 
         let result = match list {
             Some(list) => {
-                let vec: Vec<_> = list
-                    .into_iter()
+                list.into_iter()
                     .filter_map(|value| {
                         // Handle none transform.
                         if value.is_none() {
@@ -3212,12 +3211,11 @@ fn static_assert() {
                             Some(Self::clone_single_transform_function(value))
                         }
                     })
-                    .collect();
-                if !vec.is_empty() { Some(vec) } else { None }
+                    .collect::<Vec<_>>()
             },
-            _ => None,
+            _ => vec![],
         };
-        Transform(result.unwrap_or(vec!()))
+        Transform(result)
     }
 
     ${impl_transition_time_value('delay', 'Delay')}
diff --git a/components/style/properties/helpers/animated_properties.mako.rs b/components/style/properties/helpers/animated_properties.mako.rs
index 7f637fa26cd..b054e3f9863 100644
--- a/components/style/properties/helpers/animated_properties.mako.rs
+++ b/components/style/properties/helpers/animated_properties.mako.rs
@@ -1438,6 +1438,8 @@ impl Animate for Matrix3D {
     }
 
     #[cfg(feature = "gecko")]
+    // Gecko doesn't exactly follow the spec here; we use a different procedure
+    // to match it
     fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
         let (from, to) = if self.is_3d() || other.is_3d() {
             (decompose_3d_matrix(*self), decompose_3d_matrix(*other))
@@ -1467,6 +1469,8 @@ impl Animate for Matrix {
     }
 
     #[cfg(feature = "gecko")]
+    // Gecko doesn't exactly follow the spec here; we use a different procedure
+    // to match it
     fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
         let from = decompose_2d_matrix(&(*self).into());
         let to = decompose_2d_matrix(&(*other).into());
@@ -2471,6 +2475,9 @@ impl ComputeSquaredDistance for ComputedTransformOperation {
                 }
                 p_matrix.compute_squared_distance(&m)
             }
+            // Gecko cross-interpolates amongst all translate and all scale
+            // functions (See ToPrimitive in layout/style/StyleAnimationValue.cpp)
+            // without falling back to InterpolateMatrix
             _ if self.is_translate() && other.is_translate() => {
                 self.to_translate_3d().compute_squared_distance(&other.to_translate_3d())
             }
diff --git a/components/style/values/computed/transform.rs b/components/style/values/computed/transform.rs
index 3be9816b34c..440758a06b1 100644
--- a/components/style/values/computed/transform.rs
+++ b/components/style/values/computed/transform.rs
@@ -59,6 +59,8 @@ pub type Matrix = GenericMatrix<Number>;
 /// computed value of matrix() in -moz-transform
 pub type PrefixedMatrix = GenericMatrix<Number, LengthOrPercentageOrNumber>;
 
+// we rustfmt_skip here because we want the matrices to look like
+// matrices instead of being split across lines
 #[cfg_attr(rustfmt, rustfmt_skip)]
 impl Matrix3D {
     #[inline]