From 992059c8560fddd92bb49d709f606ef72f0d71f0 Mon Sep 17 00:00:00 2001
From: Bobby Holley <bobbyholley@gmail.com>
Date: Thu, 1 Jun 2017 17:03:35 -0700
Subject: [PATCH] Move around specificity computation so that we know it by the
 time we mint the Selector.

This is important to make the selector immutable, which needs to happen when we stick it in an Arc.

MozReview-Commit-ID: BaMbOEbYC3D
---
 components/selectors/parser.rs | 38 +++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/components/selectors/parser.rs b/components/selectors/parser.rs
index 4c40ab54bb4..0049c4e5286 100644
--- a/components/selectors/parser.rs
+++ b/components/selectors/parser.rs
@@ -841,13 +841,13 @@ impl From<Specificity> for u32 {
     }
 }
 
-fn specificity<Impl>(complex_selector: &Selector<Impl>) -> u32
+fn specificity<Impl>(iter: SelectorIter<Impl>) -> u32
     where Impl: SelectorImpl
 {
-    complex_selector_specificity(complex_selector).into()
+    complex_selector_specificity(iter).into()
 }
 
-fn complex_selector_specificity<Impl>(selector: &Selector<Impl>)
+fn complex_selector_specificity<Impl>(mut iter: SelectorIter<Impl>)
                                       -> Specificity
     where Impl: SelectorImpl
 {
@@ -896,9 +896,7 @@ fn complex_selector_specificity<Impl>(selector: &Selector<Impl>)
         }
     }
 
-
     let mut specificity = Default::default();
-    let mut iter = selector.iter();
     loop {
         for simple_selector in &mut iter {
             simple_selector_specificity(&simple_selector, &mut specificity);
@@ -917,12 +915,7 @@ fn complex_selector_specificity<Impl>(selector: &Selector<Impl>)
 fn parse_selector<P, Impl>(parser: &P, input: &mut CssParser) -> Result<Selector<Impl>, ()>
     where P: Parser<Impl=Impl>, Impl: SelectorImpl
 {
-    let (mut selector, has_pseudo_element) = parse_complex_selector(parser, input)?;
-    let mut specificity = specificity(&selector);
-    if has_pseudo_element {
-        specificity |= HAS_PSEUDO_BIT;
-    }
-    selector.1 = specificity;
+    let selector = parse_complex_selector(parser, input)?;
     Ok(selector)
 }
 
@@ -944,7 +937,7 @@ type ParseVec<Impl> = SmallVec<[Component<Impl>; 8]>;
 fn parse_complex_selector<P, Impl>(
         parser: &P,
         input: &mut CssParser)
-        -> Result<(Selector<Impl>, bool), ()>
+        -> Result<Selector<Impl>, ()>
     where P: Parser<Impl=Impl>, Impl: SelectorImpl
 {
     let mut sequence = ParseVec::new();
@@ -992,21 +985,28 @@ fn parse_complex_selector<P, Impl>(
         sequence.push(Component::Combinator(combinator));
     }
 
-    let complex = Selector(ArcSlice::new(sequence.into_vec().into_boxed_slice()), 0);
-    Ok((complex, parsed_pseudo_element))
+    let mut specificity = specificity(SelectorIter {
+        iter: sequence.iter().rev(),
+        next_combinator: None,
+    });
+    if parsed_pseudo_element {
+        specificity |= HAS_PSEUDO_BIT;
+    }
+
+    let complex = Selector(ArcSlice::new(sequence.into_vec().into_boxed_slice()), specificity);
+    Ok(complex)
 }
 
 impl<Impl: SelectorImpl> Selector<Impl> {
-    /// Parse a complex selector, without any pseudo-element.
+    /// Parse a selector, without any pseudo-element.
     pub fn parse<P>(parser: &P, input: &mut CssParser) -> Result<Self, ()>
         where P: Parser<Impl=Impl>
     {
-        let (complex, has_pseudo_element) =
-            parse_complex_selector(parser, input)?;
-        if has_pseudo_element {
+        let selector = parse_complex_selector(parser, input)?;
+        if selector.has_pseudo_element() {
             return Err(())
         }
-        Ok(complex)
+        Ok(selector)
     }
 }