X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fsrc%2Fmsg%2Fasync%2Fdpdk%2Fshared_ptr.h;fp=src%2Fceph%2Fsrc%2Fmsg%2Fasync%2Fdpdk%2Fshared_ptr.h;h=11fbf2c90582a2e81aac837d6b707f37950851c9;hb=812ff6ca9fcd3e629e49d4328905f33eee8ca3f5;hp=0000000000000000000000000000000000000000;hpb=15280273faafb77777eab341909a3f495cf248d9;p=stor4nfv.git

diff --git a/src/ceph/src/msg/async/dpdk/shared_ptr.h b/src/ceph/src/msg/async/dpdk/shared_ptr.h
new file mode 100644
index 0000000..11fbf2c
--- /dev/null
+++ b/src/ceph/src/msg/async/dpdk/shared_ptr.h
@@ -0,0 +1,266 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+/*
+ * This file is open source software, licensed to you under the terms
+ * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
+ * distributed with this work for additional information regarding copyright
+ * ownership.  You may not use this file except in compliance with the License.
+ *
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Copyright (C) 2014 Cloudius Systems, Ltd.
+ */
+
+#ifndef CEPH_LW_SHARED_PTR_H_
+#define CEPH_LW_SHARED_PTR_H_
+
+#include <utility>
+#include <type_traits>
+#include <functional>
+#include <iostream>
+
+// This header defines two shared pointer facilities, lw_shared_ptr<>
+// modeled after std::shared_ptr<>.
+//
+// Unlike std::shared_ptr<>, neither of these implementations are thread
+// safe, and two pointers sharing the same object must not be used in
+// different threads.
+//
+// lw_shared_ptr<> is the more lightweight variant, with a lw_shared_ptr<>
+// occupying just one machine word, and adding just one word to the shared
+// object.  However, it does not support polymorphism.
+//
+// Both variants support shared_from_this() via enable_shared_from_this<>
+// and lw_enable_shared_from_this<>().
+//
+
+template< class T >
+using remove_const_t = typename remove_const<T>::type;
+
+template <typename T>
+class lw_shared_ptr;
+
+template <typename T, typename... A>
+lw_shared_ptr<T> make_lw_shared(A&&... a);
+
+template <typename T>
+lw_shared_ptr<T> make_lw_shared(T&& a);
+
+template <typename T>
+lw_shared_ptr<T> make_lw_shared(T& a);
+
+// CRTP from this to enable shared_from_this:
+template <typename T>
+class enable_lw_shared_from_this {
+  long _count = 0;
+  using ctor = T;
+  T* to_value() { return static_cast<T*>(this); }
+  T* to_internal_object() { return static_cast<T*>(this); }
+ protected:
+  enable_lw_shared_from_this() noexcept {}
+  enable_lw_shared_from_this(enable_lw_shared_from_this&&) noexcept {}
+  enable_lw_shared_from_this(const enable_lw_shared_from_this&) noexcept {}
+  enable_lw_shared_from_this& operator=(const enable_lw_shared_from_this&) noexcept { return *this; }
+  enable_lw_shared_from_this& operator=(enable_lw_shared_from_this&&) noexcept { return *this; }
+ public:
+  lw_shared_ptr<T> shared_from_this();
+  lw_shared_ptr<const T> shared_from_this() const;
+  template <typename X>
+  friend class lw_shared_ptr;
+};
+
+template <typename T>
+struct shared_ptr_no_esft {
+  T _value;
+  using ctor = shared_ptr_no_esft;
+
+  T* to_value() { return &_value; }
+  shared_ptr_no_esft* to_internal_object() { return this; }
+  shared_ptr_no_esft() = default;
+  shared_ptr_no_esft(const T& x) : _value(x) {}
+  shared_ptr_no_esft(T&& x) : _value(std::move(x)) {}
+  template <typename... A>
+  shared_ptr_no_esft(A&&... a) : _value(std::forward<A>(a)...) {}
+  template <typename X>
+  friend class lw_shared_ptr;
+};
+
+template <typename T>
+using shared_ptr_impl = typename std::conditional<
+        std::is_base_of<enable_lw_shared_from_this<remove_const_t<T>>, T>::value,
+        enable_lw_shared_from_this<remove_const_t<T>>,
+        shared_ptr_no_esft<remove_const_t<T>> >::type;
+
+template <typename T>
+class lw_shared_ptr {
+  mutable shared_ptr_impl<T>* _p = nullptr;
+ private:
+  lw_shared_ptr(shared_ptr_impl<T>* p) noexcept : _p(p) {
+    if (_p) {
+      ++_p->_count;
+    }
+  }
+  template <typename... A>
+  static lw_shared_ptr make(A&&... a) {
+      return lw_shared_ptr(new typename shared_ptr_impl<T>::ctor(std::forward<A>(a)...));
+  }
+ public:
+  using element_type = T;
+
+  lw_shared_ptr() noexcept = default;
+  lw_shared_ptr(std::nullptr_t) noexcept : lw_shared_ptr() {}
+  lw_shared_ptr(const lw_shared_ptr& x) noexcept : _p(x._p) {
+    if (_p) {
+      ++_p->_count;
+    }
+  }
+  lw_shared_ptr(lw_shared_ptr&& x) noexcept  : _p(x._p) {
+      x._p = nullptr;
+  }
+  [[gnu::always_inline]]
+  ~lw_shared_ptr() {
+    if (_p && !--_p->_count) {
+      delete _p->to_internal_object();
+    }
+  }
+  lw_shared_ptr& operator=(const lw_shared_ptr& x) noexcept {
+      if (_p != x._p) {
+          this->~lw_shared_ptr();
+          new (this) lw_shared_ptr(x);
+      }
+      return *this;
+  }
+  lw_shared_ptr& operator=(lw_shared_ptr&& x) noexcept {
+      if (_p != x._p) {
+          this->~lw_shared_ptr();
+          new (this) lw_shared_ptr(std::move(x));
+      }
+      return *this;
+  }
+  lw_shared_ptr& operator=(std::nullptr_t) noexcept {
+      return *this = lw_shared_ptr();
+  }
+  lw_shared_ptr& operator=(T&& x) noexcept {
+      this->~lw_shared_ptr();
+      new (this) lw_shared_ptr(make_lw_shared<T>(std::move(x)));
+      return *this;
+  }
+
+  T& operator*() const noexcept { return *_p->to_value(); }
+  T* operator->() const noexcept { return _p->to_value(); }
+  T* get() const noexcept { return _p->to_value(); }
+
+  long int use_count() const noexcept {
+    if (_p) {
+      return _p->_count;
+    } else {
+      return 0;
+    }
+  }
+
+  operator lw_shared_ptr<const T>() const noexcept {
+      return lw_shared_ptr<const T>(_p);
+  }
+
+  explicit operator bool() const noexcept {
+      return _p;
+  }
+
+  bool owned() const noexcept {
+    return _p->_count == 1;
+  }
+
+  bool operator==(const lw_shared_ptr<const T>& x) const {
+      return _p == x._p;
+  }
+
+  bool operator!=(const lw_shared_ptr<const T>& x) const {
+      return !operator==(x);
+  }
+
+  bool operator==(const lw_shared_ptr<remove_const_t<T>>& x) const {
+      return _p == x._p;
+  }
+
+  bool operator!=(const lw_shared_ptr<remove_const_t<T>>& x) const {
+      return !operator==(x);
+  }
+
+  template <typename U>
+  friend class lw_shared_ptr;
+
+  template <typename X, typename... A>
+  friend lw_shared_ptr<X> make_lw_shared(A&&...);
+
+  template <typename U>
+  friend lw_shared_ptr<U> make_lw_shared(U&&);
+
+  template <typename U>
+  friend lw_shared_ptr<U> make_lw_shared(U&);
+
+  template <typename U>
+  friend class enable_lw_shared_from_this;
+};
+
+template <typename T, typename... A>
+inline
+lw_shared_ptr<T> make_lw_shared(A&&... a) {
+    return lw_shared_ptr<T>::make(std::forward<A>(a)...);
+}
+
+template <typename T>
+inline
+lw_shared_ptr<T> make_lw_shared(T&& a) {
+    return lw_shared_ptr<T>::make(std::move(a));
+}
+
+template <typename T>
+inline
+lw_shared_ptr<T> make_lw_shared(T& a) {
+    return lw_shared_ptr<T>::make(a);
+}
+
+template <typename T>
+inline
+lw_shared_ptr<T>
+enable_lw_shared_from_this<T>::shared_from_this() {
+    return lw_shared_ptr<T>(this);
+}
+
+template <typename T>
+inline
+lw_shared_ptr<const T>
+enable_lw_shared_from_this<T>::shared_from_this() const {
+    return lw_shared_ptr<const T>(const_cast<enable_lw_shared_from_this*>(this));
+}
+
+template <typename T>
+static inline
+std::ostream& operator<<(std::ostream& out, const lw_shared_ptr<T>& p) {
+    if (!p) {
+        return out << "null";
+    }
+    return out << *p;
+}
+
+namespace std {
+
+  template <typename T>
+  struct hash<lw_shared_ptr<T>> : private hash<T*> {
+    size_t operator()(const lw_shared_ptr<T>& p) const {
+        return hash<T*>::operator()(p.get());
+    }
+  };
+
+}
+
+#endif /* CEPH_LW_SHARED_PTR_H_ */