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Implement PartialEq for PropertyDeclaration by hand 🐉🐲

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We first check that the discriminants are equal, then we pattern match only
on `*self` and use `PropertyDeclarationVariantRepr` to look into `other` directly.
This commit is contained in:
Anthony Ramine 2018-02-05 23:51:45 +01:00
parent 8ebf0f057f
commit 456c18f767
1 changed files with 34 additions and 9 deletions
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43
components/style/properties/properties.mako.rs
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@ -268,7 +268,6 @@ pub mod animated_properties {
/// Servo's representation for a property declaration.
#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
#[derive(PartialEq)]
#[repr(u16)]
pub enum PropertyDeclaration {
% for variant in variants:
@ -277,17 +276,17 @@ pub enum PropertyDeclaration {
% endfor
}
#[repr(C)]
struct PropertyDeclarationVariantRepr<T> {
tag: u16,
value: T
}
impl Clone for PropertyDeclaration {
#[inline]
fn clone(&self) -> Self {
use self::PropertyDeclaration::*;
#[repr(C)]
struct VariantRepr<T> {
tag: u16,
value: T
}
match *self {
% for ty, variants in groups.iteritems():
% if len(variants) == 1:
@ -299,8 +298,8 @@ impl Clone for PropertyDeclaration {
unsafe {
let mut out = ManuallyDrop::new(mem::uninitialized());
ptr::write(
&mut out as *mut _ as *mut VariantRepr<${ty}>,
VariantRepr {
&mut out as *mut _ as *mut PropertyDeclarationVariantRepr<${ty}>,
PropertyDeclarationVariantRepr {
tag: *(self as *const _ as *const u16),
value: value.clone(),
},
@ -314,6 +313,32 @@ impl Clone for PropertyDeclaration {
}
}
impl PartialEq for PropertyDeclaration {
#[inline]
fn eq(&self, other: &Self) -> bool {
use self::PropertyDeclaration::*;
unsafe {
let this_repr =
&*(self as *const _ as *const PropertyDeclarationVariantRepr<()>);
let other_repr =
&*(other as *const _ as *const PropertyDeclarationVariantRepr<()>);
if this_repr.tag != other_repr.tag {
return false;
}
match *self {
% for ty, variants in groups.iteritems():
${" | ".join("{}(ref this)".format(v) for v in variants)} => {
let other_repr =
&*(other as *const _ as *const PropertyDeclarationVariantRepr<${ty}>);
*this == other_repr.value
}
% endfor
}
}
}
}
impl PropertyDeclaration {
/// Like the method on ToCss, but without the type parameter to avoid
/// accidentally monomorphizing this large function multiple times for