2 * Copyright 2017 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include <folly/experimental/hazptr/debug.h>
20 ////////////////////////////////////////////////////////////////////////////////
21 /// Disclaimer: This is intended only as a partial stand-in for
22 /// std::pmr::memory_resource (C++17) as needed for developing a
24 ////////////////////////////////////////////////////////////////////////////////
25 #include <folly/Portability.h>
31 class memory_resource {
33 virtual ~memory_resource() = default;
34 virtual void* allocate(
36 const size_t alignment = folly::max_align_v) = 0;
37 virtual void deallocate(
40 const size_t alignment = folly::max_align_v) = 0;
43 memory_resource* get_default_resource();
44 void set_default_resource(memory_resource*);
45 memory_resource* new_delete_resource();
47 ////////////////////////////////////////////////////////////////////////////////
49 ////////////////////////////////////////////////////////////////////////////////
51 inline memory_resource** default_mr_ptr() {
52 /* library-local */ static memory_resource* default_mr =
53 new_delete_resource();
54 DEBUG_PRINT(&default_mr << " " << default_mr);
58 inline memory_resource* get_default_resource() {
60 return *default_mr_ptr();
63 inline void set_default_resource(memory_resource* mr) {
65 *default_mr_ptr() = mr;
68 inline memory_resource* new_delete_resource() {
69 class new_delete : public memory_resource {
73 const size_t alignment = folly::max_align_v) override {
75 void* p = static_cast<void*>(new char[bytes]);
76 DEBUG_PRINT(this << " " << p << " " << bytes);
82 const size_t alignment = folly::max_align_v) override {
85 DEBUG_PRINT(p << " " << bytes);
86 delete[] static_cast<char*>(p);