// Copyright 2018 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/metal/StagingBufferMTL.h"
#include "dawn_native/metal/DeviceMTL.h"

namespace dawn_native::metal {

    StagingBuffer::StagingBuffer(size_t size, Device* device)
        : StagingBufferBase(size), mDevice(device) {
    }

    MaybeError StagingBuffer::Initialize() {
        const size_t bufferSize = GetSize();
        mBuffer = AcquireNSPRef([mDevice->GetMTLDevice()
            newBufferWithLength:bufferSize
                        options:MTLResourceStorageModeShared]);

        if (mBuffer == nullptr) {
            return DAWN_OUT_OF_MEMORY_ERROR("Unable to allocate buffer.");
        }

        mMappedPointer = [*mBuffer contents];
        if (mMappedPointer == nullptr) {
            return DAWN_INTERNAL_ERROR("Unable to map staging buffer.");
        }

        return {};
    }

    id<MTLBuffer> StagingBuffer::GetBufferHandle() const {
        return mBuffer.Get();
    }

}  // namespace dawn_native::metal