80 lines
3.1 KiB
C++
80 lines
3.1 KiB
C++
// Copyright 2020 The Dawn Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "dawn_wire/ChunkedCommandHandler.h"
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#include "common/Alloc.h"
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#include <algorithm>
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#include <cstring>
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namespace dawn_wire {
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ChunkedCommandHandler::~ChunkedCommandHandler() = default;
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const volatile char* ChunkedCommandHandler::HandleCommands(const volatile char* commands,
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size_t size) {
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if (mChunkedCommandRemainingSize > 0) {
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// If there is a chunked command in flight, append the command data.
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// We append at most |mChunkedCommandRemainingSize| which is enough to finish the
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// in-flight chunked command, and then pass the rest along to a second call to
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// |HandleCommandsImpl|.
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size_t chunkSize = std::min(size, mChunkedCommandRemainingSize);
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memcpy(mChunkedCommandData.get() + mChunkedCommandPutOffset,
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const_cast<const char*>(commands), chunkSize);
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mChunkedCommandPutOffset += chunkSize;
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mChunkedCommandRemainingSize -= chunkSize;
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commands += chunkSize;
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size -= chunkSize;
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if (mChunkedCommandRemainingSize == 0) {
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// Once the chunked command is complete, pass the data to the command handler
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// implemenation.
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auto chunkedCommandData = std::move(mChunkedCommandData);
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if (HandleCommandsImpl(chunkedCommandData.get(), mChunkedCommandPutOffset) ==
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nullptr) {
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// |HandleCommandsImpl| returns nullptr on error. Forward any errors
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// out.
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return nullptr;
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}
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}
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}
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return HandleCommandsImpl(commands, size);
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}
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ChunkedCommandHandler::ChunkedCommandsResult ChunkedCommandHandler::BeginChunkedCommandData(
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const volatile char* commands,
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size_t commandSize,
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size_t initialSize) {
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ASSERT(!mChunkedCommandData);
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// Reserve space for all the command data we're expecting, and copy the initial data
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// to the start of the memory.
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mChunkedCommandData.reset(AllocNoThrow<char>(commandSize));
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if (!mChunkedCommandData) {
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return ChunkedCommandsResult::Error;
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}
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memcpy(mChunkedCommandData.get(), const_cast<const char*>(commands), initialSize);
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mChunkedCommandPutOffset = initialSize;
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mChunkedCommandRemainingSize = commandSize - initialSize;
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return ChunkedCommandsResult::Consumed;
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}
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} // namespace dawn_wire
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