Eliminate unneeded clones in find_or_create

...and use it to eliminate duplicate hash lookups and string copies in shape_text.

1 files changed, 15 insertions, 16 deletions

diff --git a/components/util/cache.rs b/components/util/cache.rs
index 7b8d7bfb1a0..7af590b015e 100644
--- a/components/util/cache.rs
+++ b/components/util/cache.rs
@@ -13,14 +13,14 @@ use std::slice::Iter;
 
 #[derive(Debug)]
 pub struct HashCache<K, V>
-    where K: Clone + PartialEq + Eq + Hash,
+    where K: PartialEq + Eq + Hash,
           V: Clone,
 {
     entries: HashMap<K, V, BuildHasherDefault<SipHasher>>,
 }
 
 impl<K, V> HashCache<K, V>
-    where K: Clone + PartialEq + Eq + Hash,
+    where K: PartialEq + Eq + Hash,
           V: Clone,
 {
     pub fn new() -> HashCache<K, V> {
@@ -40,13 +40,13 @@ impl<K, V> HashCache<K, V>
         }
     }
 
-    pub fn find_or_create<F>(&mut self, key: &K, blk: F) -> V where F: Fn(&K) -> V {
-        match self.entries.entry(key.clone()) {
+    pub fn find_or_create<F>(&mut self, key: K, mut blk: F) -> V where F: FnMut() -> V {
+        match self.entries.entry(key) {
             Occupied(occupied) => {
                 (*occupied.get()).clone()
             }
             Vacant(vacant) => {
-                (*vacant.insert(blk(key))).clone()
+                (*vacant.insert(blk())).clone()
             }
         }
     }
@@ -61,7 +61,7 @@ pub struct LRUCache<K, V> {
     cache_size: usize,
 }
 
-impl<K: Clone + PartialEq, V: Clone> LRUCache<K, V> {
+impl<K: PartialEq, V: Clone> LRUCache<K, V> {
     pub fn new(size: usize) -> LRUCache<K, V> {
         LRUCache {
           entries: vec!(),
@@ -97,12 +97,12 @@ impl<K: Clone + PartialEq, V: Clone> LRUCache<K, V> {
         }
     }
 
-    pub fn find_or_create<F>(&mut self, key: &K, blk: F) -> V where F: Fn(&K) -> V {
-        match self.entries.iter().position(|&(ref k, _)| *k == *key) {
+    pub fn find_or_create<F>(&mut self, key: K, mut blk: F) -> V where F: FnMut() -> V {
+        match self.entries.iter().position(|&(ref k, _)| *k == key) {
             Some(pos) => self.touch(pos),
             None => {
-                let val = blk(key);
-                self.insert(key.clone(), val.clone());
+                let val = blk();
+                self.insert(key, val.clone());
                 val
             }
         }
@@ -154,13 +154,12 @@ impl<K: Clone + Eq + Hash, V: Clone> SimpleHashCache<K, V> {
         }
     }
 
-    pub fn find_or_create<F>(&mut self, key: &K, blk: F) -> V where F: Fn(&K) -> V {
-        match self.find(key) {
-            Some(value) => return value,
-            None => {}
+    pub fn find_or_create<F>(&mut self, key: K, mut blk: F) -> V where F: FnMut() -> V {
+        if let Some(value) = self.find(&key) {
+            return value;
         }
-        let value = blk(key);
-        self.insert((*key).clone(), value.clone());
+        let value = blk();
+        self.insert(key, value.clone());
         value
     }