style: Derive more.

Differential Revision: https://phabricator.services.mozilla.com/D17029

components/style/context.rs

@@ -304,7 +304,7 @@ impl ElementCascadeInputs {
 /// Statistics gathered during the traversal. We gather statistics on each
 /// thread and then combine them after the threads join via the Add
 /// implementation below.
-#[derive(Default)]
+#[derive(AddAssign, Clone, Default)]
 pub struct PerThreadTraversalStatistics {
     /// The total number of elements traversed.
     pub elements_traversed: u32,
@@ -319,20 +319,6 @@ pub struct PerThreadTraversalStatistics {
     pub styles_reused: u32,
 }
 
-/// Implementation of Add to aggregate statistics across different threads.
-impl<'a> ops::Add for &'a PerThreadTraversalStatistics {
-    type Output = PerThreadTraversalStatistics;
-    fn add(self, other: Self) -> PerThreadTraversalStatistics {
-        PerThreadTraversalStatistics {
-            elements_traversed: self.elements_traversed + other.elements_traversed,
-            elements_styled: self.elements_styled + other.elements_styled,
-            elements_matched: self.elements_matched + other.elements_matched,
-            styles_shared: self.styles_shared + other.styles_shared,
-            styles_reused: self.styles_reused + other.styles_reused,
-        }
-    }
-}
-
 /// Statistics gathered during the traversal plus some information from
 /// other sources including stylist.
 #[derive(Default)]

components/style/driver.rs

@@ -161,10 +161,11 @@ pub fn traverse_dom<E, D>(
         let parallel = maybe_tls.is_some();
         if let Some(ref mut tls) = maybe_tls {
             let slots = unsafe { tls.unsafe_get() };
-            aggregate = slots.iter().fold(aggregate, |acc, t| match *t.borrow() {
-                None => acc,
-                Some(ref cx) => &cx.statistics + &acc,
-            });
+            for slot in slots {
+                if let Some(ref cx) = *slot.borrow() {
+                    aggregate += cx.statistics.clone();
+                }
+            }
         }
 
         if report_stats {

components/style/lib.rs

@@ -37,6 +37,8 @@ extern crate crossbeam_channel;
 #[macro_use]
 extern crate cssparser;
 #[macro_use]
+extern crate derive_more;
+#[macro_use]
 extern crate debug_unreachable;
 extern crate euclid;
 extern crate fallible;

components/style/values/computed/angle.rs

@@ -9,13 +9,12 @@ use crate::values::CSSFloat;
 use num_traits::Zero;
 use std::f64::consts::PI;
 use std::fmt::{self, Write};
-use std::ops::Add;
 use std::{f32, f64};
 use style_traits::{CssWriter, ToCss};
 
 /// A computed angle in degrees.
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-#[derive(Animate, Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd, ToAnimatedZero)]
+#[derive(Add, Animate, Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd, ToAnimatedZero)]
 pub struct Angle(CSSFloat);
 
 impl ToCss for Angle {
@@ -66,15 +65,6 @@ impl Angle {
     }
 }
 
-impl Add for Angle {
-    type Output = Self;
-
-    #[inline]
-    fn add(self, rhs: Self) -> Self {
-        Angle(self.0 + rhs.0)
-    }
-}
-
 impl Zero for Angle {
     #[inline]
     fn zero() -> Self {

components/style/values/distance.rs

@@ -31,7 +31,7 @@ pub trait ComputeSquaredDistance {
 }
 
 /// A distance between two animatable values.
-#[derive(Clone, Copy, Debug)]
+#[derive(Add, Clone, Copy, Debug, From)]
 pub struct SquaredDistance {
     value: f64,
 }
@@ -114,24 +114,6 @@ impl SquaredDistance {
     }
 }
 
-impl From<SquaredDistance> for f64 {
-    #[inline]
-    fn from(distance: SquaredDistance) -> Self {
-        distance.value
-    }
-}
-
-impl Add for SquaredDistance {
-    type Output = Self;
-
-    #[inline]
-    fn add(self, rhs: Self) -> Self {
-        SquaredDistance {
-            value: self.value + rhs.value,
-        }
-    }
-}
-
 impl Sum for SquaredDistance {
     fn sum<I>(iter: I) -> Self
     where

components/style/values/specified/svg_path.rs

@@ -11,7 +11,6 @@ use crate::values::CSSFloat;
 use cssparser::Parser;
 use std::fmt::{self, Write};
 use std::iter::{Cloned, Peekable};
-use std::ops::AddAssign;
 use std::slice;
 use style_traits::values::SequenceWriter;
 use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
@@ -491,6 +490,7 @@ impl IsAbsolute {
 
 /// The path coord type.
 #[derive(
+    AddAssign,
     Animate,
     Clone,
     ComputeSquaredDistance,
@@ -513,14 +513,6 @@ impl CoordPair {
     }
 }
 
-impl AddAssign for CoordPair {
-    #[inline]
-    fn add_assign(&mut self, other: Self) {
-        self.0 += other.0;
-        self.1 += other.1;
-    }
-}
-
 /// The EllipticalArc flag type.
 #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo)]
 #[repr(C)]