Merge pull request #328 from Eh2406/master

Faster Ord when Eq

Author: dtolnay

src/identifier.rs

@@ -257,12 +257,18 @@ impl Drop for Identifier {
     }
 }
 
+impl Identifier {
+    pub(crate) fn ptr_eq(&self, rhs: &Self) -> bool {
+        self.head == rhs.head && self.tail == rhs.tail
+    }
+}
+
 impl PartialEq for Identifier {
     fn eq(&self, rhs: &Self) -> bool {
-        if self.is_empty_or_inline() {
+        if self.ptr_eq(rhs) {
             // Fast path (most common)
-            self.head == rhs.head && self.tail == rhs.tail
-        } else if rhs.is_empty_or_inline() {
+            true
+        } else if self.is_empty_or_inline() || rhs.is_empty_or_inline() {
             false
         } else {
             // SAFETY: both reprs are in the heap allocated representation.

src/impls.rs

@@ -50,8 +50,10 @@ impl PartialOrd for BuildMetadata {
 
 impl Ord for Prerelease {
     fn cmp(&self, rhs: &Self) -> Ordering {
+        if self.identifier.ptr_eq(&rhs.identifier) {
+            return Ordering::Equal;
+        }
         match self.is_empty() {
-            true if rhs.is_empty() => return Ordering::Equal,
             // A real release compares greater than prerelease.
             true => return Ordering::Greater,
             // Prerelease compares less than the real release.
@@ -105,6 +107,9 @@ impl Ord for Prerelease {
 
 impl Ord for BuildMetadata {
     fn cmp(&self, rhs: &Self) -> Ordering {
+        if self.identifier.ptr_eq(&rhs.identifier) {
+            return Ordering::Equal;
+        }
         let lhs = self.as_str().split('.');
         let mut rhs = rhs.as_str().split('.');