| // Copyright 2017 The Dawn Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // 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. |
| |
| #include "dawn_native/RefCounted.h" |
| |
| #include "common/Assert.h" |
| |
| namespace dawn_native { |
| |
| static constexpr size_t kPayloadBits = 1; |
| static constexpr uint64_t kPayloadMask = (uint64_t(1) << kPayloadBits) - 1; |
| static constexpr uint64_t kRefCountIncrement = (uint64_t(1) << kPayloadBits); |
| |
| RefCounted::RefCounted(uint64_t payload) : mRefCount(kRefCountIncrement + payload) { |
| ASSERT((payload & kPayloadMask) == payload); |
| } |
| |
| RefCounted::~RefCounted() { |
| } |
| |
| uint64_t RefCounted::GetRefCountForTesting() const { |
| return mRefCount >> kPayloadBits; |
| } |
| |
| uint64_t RefCounted::GetRefCountPayload() const { |
| // We only care about the payload bits of the refcount. These never change after |
| // initialization so we can use the relaxed memory order. The order doesn't guarantee |
| // anything except the atomicity of the load, which is enough since any past values of the |
| // atomic will have the correct payload bits. |
| return kPayloadMask & mRefCount.load(std::memory_order_relaxed); |
| } |
| |
| void RefCounted::Reference() { |
| ASSERT((mRefCount & ~kPayloadMask) != 0); |
| mRefCount += kRefCountIncrement; |
| } |
| |
| void RefCounted::Release() { |
| ASSERT((mRefCount & ~kPayloadMask) != 0); |
| |
| mRefCount -= kRefCountIncrement; |
| if (mRefCount < kRefCountIncrement) { |
| delete this; |
| } |
| } |
| |
| } // namespace dawn_native |