Stop using std::shared_ptr<X>::unique()

bredelings · Jul 25, 2024 · 5ae1a59 · 5ae1a59
1 parent c5722fd
commit 5ae1a59
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Showing 2 changed files with 3 additions and 20 deletions.
diff --git a/src/computation/object.H b/src/computation/object.H
@@ -107,16 +107,6 @@ template<> std::string Box<Matrix>::print() const;
 
 template<> std::string Box<std::vector<std::pair<int,int>>>::print() const;
 
-template <typename T>
-bool unshare(object_ptr<T>& ptr)
-{
-    if (ptr.unique()) return false;
-
-    ptr = object_ptr<T>(ptr->clone());
-
-    return true;
-}
-
 template <typename T>
 using Vector = Box<std::vector<T>>;
 

diff --git a/src/util/include/util/cow-ptr.H b/src/util/include/util/cow-ptr.H
@@ -53,7 +53,8 @@ private:
   // create a new copy of data = make a direct copy otherwise
   void copy()
   {
-    if (not data.unique()) {
+    // Note that shared_ptr<X>::use_count() isn't thread-safe.
+    if (data.use_count() > 1) {
       X* data_old = data.get();
       data = std::shared_ptr<X>(new X(*data_old));
     }
@@ -101,10 +102,6 @@ public:
     return data.use_count();
   }
 
-  bool unique() const {
-    return data.unique(); 
-  }
-
   void swap(cow_ptr<X>& other) {std::swap(data,other.data);}
 
   cow_ptr& operator=(const cow_ptr& r)
@@ -167,7 +164,7 @@ private:
   // create a new copy of data = make a direct copy otherwise
   void copy()
   {
-    if (not data.unique()) {
+    if (data.use_count() > 1) {
       X* data_old = data.get();
       data = std::shared_ptr<X>(data_old->clone());
     }
@@ -216,10 +213,6 @@ public:
     return data.use_count();
   }
 
-  bool unique() const {
-    return data.unique(); 
-  }
-
   void swap(polymorphic_cow_ptr<X>& other) {std::swap(data,other.data);}
 
   polymorphic_cow_ptr& operator=(const polymorphic_cow_ptr& r)