Bug 1626570 - Improve handling of copying arrays in layout/style/ and servo/. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D72351

layout/style/nsStyleAutoArray.h

@@ -23,7 +23,7 @@ class nsStyleAutoArray {
   nsStyleAutoArray(const nsStyleAutoArray& aOther) { *this = aOther; }
   nsStyleAutoArray& operator=(const nsStyleAutoArray& aOther) {
     mFirstElement = aOther.mFirstElement;
-    mOtherElements = aOther.mOtherElements;
+    mOtherElements = aOther.mOtherElements.Clone();
     return *this;
   }
 

layout/style/nsStyleStruct.h

@@ -1981,6 +1981,7 @@ STATIC_ASSERT_TYPE_LAYOUTS_MATCH(mozilla::UniquePtr<int>,
  */
 template <typename T>
 class nsTArray_Simple {
+ protected:
   T* mBuffer;
 
  public:
@@ -1991,6 +1992,12 @@ class nsTArray_Simple {
   }
 };
 
+/**
+ * <div rustbindgen replaces="CopyableTArray"></div>
+ */
+template <typename T>
+class CopyableTArray_Simple : public nsTArray_Simple<T> {};
+
 STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsTArray<nsStyleImageLayers::Layer>,
                                  nsTArray_Simple<nsStyleImageLayers::Layer>);
 STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsTArray<mozilla::StyleTransition>,

servo/components/style/gecko_bindings/sugar/ns_t_array.rs

@@ -5,7 +5,7 @@
 //! Rust helpers for Gecko's nsTArray.
 
 use crate::gecko_bindings::bindings;
-use crate::gecko_bindings::structs::{nsTArray, nsTArrayHeader};
+use crate::gecko_bindings::structs::{nsTArray, nsTArrayHeader, CopyableTArray};
 use std::mem;
 use std::ops::{Deref, DerefMut};
 use std::slice;
@@ -128,3 +128,16 @@ impl<T> nsTArray<T> {
         self.iter_mut().zip(iter).for_each(|(r, v)| *r = v);
     }
 }
+
+impl<T> Deref for CopyableTArray<T> {
+    type Target = nsTArray<T>;
+    fn deref(&self) -> &Self::Target {
+        &self._base
+    }
+}
+
+impl<T> DerefMut for CopyableTArray<T> {
+    fn deref_mut(&mut self) -> &mut nsTArray<T> {
+        &mut self._base
+    }
+}

servo/ports/geckolib/cbindgen.toml

@@ -233,6 +233,7 @@ renaming_overrides_prefixing = true
 "nsACString" = "nsACString"
 "nsAString" = "nsAString"
 "nsString" = "nsString"
+"CopyableTArray" = "CopyableTArray"
 "nsTArray" = "nsTArray"
 "nsPresContext" = "nsPresContext"
 "ComputedTiming" = "ComputedTiming"

servo/ports/geckolib/glue.rs

@@ -5791,7 +5791,7 @@ fn fill_in_missing_keyframe_values(
         if !longhands_at_offset.contains(property) {
             unsafe {
                 Gecko_AppendPropertyValuePair(
-                    &mut (*keyframe).mPropertyValues,
+                    &mut *(*keyframe).mPropertyValues,
                     property.to_nscsspropertyid(),
                 );
             }
@@ -5873,7 +5873,7 @@ pub unsafe extern "C" fn Servo_StyleSet_GetKeyframesForName(
                     seen.insert(property);
 
                     Gecko_AppendPropertyValuePair(
-                        &mut (*keyframe).mPropertyValues,
+                        &mut *(*keyframe).mPropertyValues,
                         property.to_nscsspropertyid(),
                     );
                 }
@@ -5922,7 +5922,7 @@ pub unsafe extern "C" fn Servo_StyleSet_GetKeyframesForName(
                     }
 
                     let pair = Gecko_AppendPropertyValuePair(
-                        &mut (*keyframe).mPropertyValues,
+                        &mut *(*keyframe).mPropertyValues,
                         id.to_nscsspropertyid(),
                     );
 
@@ -5945,7 +5945,7 @@ pub unsafe extern "C" fn Servo_StyleSet_GetKeyframesForName(
 
                 if custom_properties.any_normal() {
                     let pair = Gecko_AppendPropertyValuePair(
-                        &mut (*keyframe).mPropertyValues,
+                        &mut *(*keyframe).mPropertyValues,
                         nsCSSPropertyID::eCSSPropertyExtra_variable,
                     );