Auto merge of servo#19537 - mbrubeck:try, r=nox

style: Use the ? operator for Option

This is stable in Rust 1.22 (servo#19532).

---

- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes do not require tests because it is refactoring only

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---
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Author: bors-servo

components/layout/fragment.rs

@@ -1750,22 +1750,17 @@ impl Fragment {
 
         let character_breaking_strategy =
             text_fragment_info.run.character_slices_in_range(&text_fragment_info.range);
-        match self.calculate_split_position_using_breaking_strategy(character_breaking_strategy,
-                                                                    max_inline_size,
-                                                                    SplitOptions::empty()) {
-            None => None,
-            Some(split_info) => {
-                match split_info.inline_start {
-                    None => None,
-                    Some(split) => {
-                        Some(TruncationResult {
-                            split: split,
-                            text_run: split_info.text_run.clone(),
-                        })
-                    }
-                }
-            }
-        }
+
+        let split_info = self.calculate_split_position_using_breaking_strategy(
+                character_breaking_strategy,
+                max_inline_size,
+                SplitOptions::empty())?;
+
+        let split = split_info.inline_start?;
+        Some(TruncationResult {
+            split: split,
+            text_run: split_info.text_run.clone(),
+        })
     }
 
     /// A helper method that uses the breaking strategy described by `slice_iterator` (at present,

components/style/animation.rs

@@ -339,12 +339,7 @@ impl PropertyAnimation {
             longhand,
             old_style,
             new_style,
-        );
-
-        let animated_property = match animated_property {
-            Some(p) => p,
-            None => return None,
-        };
+        )?;
 
         let property_animation = PropertyAnimation {
             property: animated_property,

components/style/bloom.rs

@@ -169,10 +169,8 @@ impl<E: TElement> StyleBloom<E> {
     /// Pop the last element in the bloom filter and return it.
     #[inline]
     fn pop(&mut self) -> Option<E> {
-        let (popped_element, num_hashes)  = match self.elements.pop() {
-            None => return None,
-            Some(x) => (*x.element, x.num_hashes),
-        };
+        let PushedElement { element, num_hashes } = self.elements.pop()?;
+        let popped_element = *element;
 
         // Verify that the pushed hashes match the ones we'd get from the element.
         let mut expected_hashes = vec![];

components/style/custom_properties.rs

@@ -153,10 +153,7 @@ where
         K: Borrow<Q>,
         Q: PrecomputedHash + Hash + Eq,
     {
-        let index = match self.index.iter().position(|k| k.borrow() == key) {
-            Some(p) => p,
-            None => return None,
-        };
+        let index = self.index.iter().position(|k| k.borrow() == key)?;
         self.index.remove(index);
         self.values.remove(key)
     }
@@ -194,10 +191,7 @@ where
     type Item = (&'a K, &'a V);
 
     fn next(&mut self) -> Option<Self::Item> {
-        let key = match self.inner.index.get(self.pos) {
-            Some(k) => k,
-            None => return None,
-        };
+        let key = self.inner.index.get(self.pos)?;
 
         self.pos += 1;
         let value = &self.inner.values[key];

components/style/dom.rs

@@ -78,14 +78,10 @@ where
 
     fn next(&mut self) -> Option<N> {
         loop {
-            match self.0.next() {
-                Some(n) => {
-                    // Filter out nodes that layout should ignore.
-                    if n.is_text_node() || n.is_element() {
-                        return Some(n)
-                    }
-                }
-                None => return None,
+            let n = self.0.next()?;
+            // Filter out nodes that layout should ignore.
+            if n.is_text_node() || n.is_element() {
+                return Some(n)
             }
         }
     }
@@ -100,13 +96,9 @@ where
     type Item = N;
 
     fn next(&mut self) -> Option<N> {
-        match self.0.take() {
-            Some(n) => {
-                self.0 = n.next_sibling();
-                Some(n)
-            }
-            None => None,
-        }
+        let n = self.0.take()?;
+        self.0 = n.next_sibling();
+        Some(n)
     }
 }
 
@@ -124,11 +116,7 @@ where
 
     #[inline]
     fn next(&mut self) -> Option<N> {
-        let prev = match self.previous.take() {
-            None => return None,
-            Some(n) => n,
-        };
-
+        let prev = self.previous.take()?;
         self.previous = prev.next_in_preorder(Some(self.scope));
         self.previous
     }

components/style/gecko/wrapper.rs

@@ -428,10 +428,7 @@ impl<'lb> GeckoXBLBinding<'lb> {
             if !binding.anon_content().is_null() {
                 return Some(binding);
             }
-            binding = match binding.base_binding() {
-                Some(b) => b,
-                None => return None,
-            };
+            binding = binding.base_binding()?;
         }
     }
 
@@ -1006,20 +1003,14 @@ impl<'le> TElement for GeckoElement<'le> {
 
     fn closest_non_native_anonymous_ancestor(&self) -> Option<Self> {
         debug_assert!(self.is_native_anonymous());
-        let mut parent = match self.traversal_parent() {
-            Some(e) => e,
-            None => return None,
-        };
+        let mut parent = self.traversal_parent()?;
 
         loop {
             if !parent.is_native_anonymous() {
                 return Some(parent);
             }
 
-            parent = match parent.traversal_parent() {
-                Some(p) => p,
-                None => return None,
-            };
+            parent = parent.traversal_parent()?;
         }
     }
 
@@ -1054,16 +1045,10 @@ impl<'le> TElement for GeckoElement<'le> {
 
     fn get_smil_override(&self) -> Option<ArcBorrow<Locked<PropertyDeclarationBlock>>> {
         unsafe {
-            let slots = match self.get_extended_slots() {
-                Some(s) => s,
-                None => return None,
-            };
+            let slots = self.get_extended_slots()?;
 
             let base_declaration: &structs::DeclarationBlock =
-                match slots.mSMILOverrideStyleDeclaration.mRawPtr.as_ref() {
-                    Some(decl) => decl,
-                    None => return None,
-                };
+                slots.mSMILOverrideStyleDeclaration.mRawPtr.as_ref()?;
 
             assert_eq!(base_declaration.mType, structs::StyleBackendType_Servo);
             let declaration: &structs::ServoDeclarationBlock =
@@ -1074,11 +1059,7 @@ impl<'le> TElement for GeckoElement<'le> {
                 base_declaration as *const structs::DeclarationBlock
             );
 
-            let raw: &structs::RawServoDeclarationBlock =
-                match declaration.mRaw.mRawPtr.as_ref() {
-                    Some(decl) => decl,
-                    None => return None,
-                };
+            let raw: &structs::RawServoDeclarationBlock = declaration.mRaw.mRawPtr.as_ref()?;
 
             Some(Locked::<PropertyDeclarationBlock>::as_arc(
                 &*(&raw as *const &structs::RawServoDeclarationBlock)

components/style/invalidation/element/element_wrapper.rs

@@ -127,10 +127,7 @@ impl<'a, E> ElementWrapper<'a, E>
             if lang.is_some() {
                 return lang;
             }
-            match current.parent_element() {
-                Some(parent) => current = parent,
-                None => return None,
-            }
+            current = current.parent_element()?;
         }
     }
 }

components/style/rule_cache.rs

@@ -102,20 +102,16 @@ impl RuleCache {
             return None;
         }
 
-        let rules = match builder_with_early_props.rules {
-            Some(ref rules) => rules,
-            None => return None,
-        };
+        let rules = builder_with_early_props.rules.as_ref()?;
+        let cached_values = self.map.get(rules)?;
 
-        self.map.get(rules).and_then(|cached_values| {
-            for &(ref conditions, ref values) in cached_values.iter() {
-                if conditions.matches(builder_with_early_props) {
-                    debug!("Using cached reset style with conditions {:?}", conditions);
-                    return Some(&**values)
-                }
+        for &(ref conditions, ref values) in cached_values.iter() {
+            if conditions.matches(builder_with_early_props) {
+                debug!("Using cached reset style with conditions {:?}", conditions);
+                return Some(&**values)
             }
-            None
-        })
+        }
+        None
     }
 
     /// Inserts a node into the rules cache if possible.

components/style/style_resolver.rs

@@ -376,11 +376,7 @@ where
             originating_element_style.style(),
             pseudo,
             VisitedHandlingMode::AllLinksUnvisited
-        );
-        let rules = match rules {
-            Some(rules) => rules,
-            None => return None,
-        };
+        )?;
 
         let mut visited_rules = None;
         if originating_element_style.style().visited_style().is_some() {

components/style/stylesheet_set.rs

@@ -80,10 +80,7 @@ where
     fn next(&mut self) -> Option<Self::Item> {
         loop {
             if self.current.is_none() {
-                let next_origin = match self.origins.next() {
-                    Some(o) => o,
-                    None => return None,
-                };
+                let next_origin = self.origins.next()?;
 
                 self.current =
                     Some((next_origin, self.collections.borrow_for_origin(&next_origin).iter()));
@@ -238,10 +235,7 @@ where
         use std::mem;
 
         loop {
-            let potential_sheet = match self.iter.next() {
-                Some(s) => s,
-                None => return None,
-            };
+            let potential_sheet = self.iter.next()?;
 
             let dirty = mem::replace(&mut potential_sheet.dirty, false);
             if dirty {

components/style/stylesheets/origin.rs

@@ -89,10 +89,7 @@ impl Iterator for OriginSetIterator {
 
     fn next(&mut self) -> Option<Origin> {
         loop {
-            let origin = match Origin::from_index(self.cur) {
-                Some(origin) => origin,
-                None => return None,
-            };
+            let origin = Origin::from_index(self.cur)?;
 
             self.cur += 1;
 
@@ -184,10 +181,7 @@ impl<'a, T> Iterator for PerOriginIter<'a, T> where T: 'a {
     type Item = (&'a T, Origin);
 
     fn next(&mut self) -> Option<Self::Item> {
-        let origin = match Origin::from_index(self.cur) {
-            Some(origin) => origin,
-            None => return None,
-        };
+        let origin = Origin::from_index(self.cur)?;
 
         self.cur += if self.rev { -1 } else { 1 };
 
@@ -211,10 +205,7 @@ impl<'a, T> Iterator for PerOriginIterMut<'a, T> where T: 'a {
     type Item = (&'a mut T, Origin);
 
     fn next(&mut self) -> Option<Self::Item> {
-        let origin = match Origin::from_index(self.cur) {
-            Some(origin) => origin,
-            None => return None,
-        };
+        let origin = Origin::from_index(self.cur)?;
 
         self.cur += 1;
 

components/style/stylist.rs

@@ -196,11 +196,7 @@ impl<'a> Iterator for DocumentCascadeDataIter<'a> {
     type Item = (&'a CascadeData, Origin);
 
     fn next(&mut self) -> Option<Self::Item> {
-        let (_, origin) = match self.iter.next() {
-            Some(o) => o,
-            None => return None,
-        };
-
+        let (_, origin) = self.iter.next()?;
         Some((self.cascade_data.borrow_for_origin(origin), origin))
     }
 }

components/style_derive/to_css.rs

@@ -145,10 +145,7 @@ fn to_css_identifier(mut camel_case: &str) -> String {
 
 /// Given "FooBar", returns "Foo" and sets `camel_case` to "Bar".
 fn split_camel_segment<'input>(camel_case: &mut &'input str) -> Option<&'input str> {
-    let index = match camel_case.chars().next() {
-        None => return None,
-        Some(ch) => ch.len_utf8(),
-    };
+    let index = camel_case.chars().next()?.len_utf8();
     let end_position = camel_case[index..]
         .find(char::is_uppercase)
         .map_or(camel_case.len(), |pos| index + pos);