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// Copyright 2020 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/wire/ChunkedCommandHandler.h"
#include <algorithm>
#include <cstring>
#include <utility>
#include "dawn/common/Alloc.h"
namespace dawn::wire {
ChunkedCommandHandler::ChunkedCommandHandler() = default;
ChunkedCommandHandler::~ChunkedCommandHandler() = default;
const volatile char* ChunkedCommandHandler::HandleCommands(const volatile char* commands,
size_t size) {
if (mChunkedCommandRemainingSize > 0) {
// If there is a chunked command in flight, append the command data.
// We append at most |mChunkedCommandRemainingSize| which is enough to finish the
// in-flight chunked command, and then pass the rest along to a second call to
// |HandleCommandsImpl|.
size_t chunkSize = std::min(size, mChunkedCommandRemainingSize);
memcpy(mChunkedCommandData.get() + mChunkedCommandPutOffset,
const_cast<const char*>(commands), chunkSize);
mChunkedCommandPutOffset += chunkSize;
mChunkedCommandRemainingSize -= chunkSize;
commands += chunkSize;
size -= chunkSize;
if (mChunkedCommandRemainingSize == 0) {
// Once the chunked command is complete, pass the data to the command handler
// implemenation.
auto chunkedCommandData = std::move(mChunkedCommandData);
if (HandleCommandsImpl(chunkedCommandData.get(), mChunkedCommandPutOffset) == nullptr) {
// |HandleCommandsImpl| returns nullptr on error. Forward any errors
// out.
return nullptr;
}
}
}
return HandleCommandsImpl(commands, size);
}
ChunkedCommandHandler::ChunkedCommandsResult ChunkedCommandHandler::BeginChunkedCommandData(
const volatile char* commands,
size_t commandSize,
size_t initialSize) {
ASSERT(!mChunkedCommandData);
// Reserve space for all the command data we're expecting, and copy the initial data
// to the start of the memory.
mChunkedCommandData.reset(AllocNoThrow<char>(commandSize));
if (!mChunkedCommandData) {
return ChunkedCommandsResult::Error;
}
memcpy(mChunkedCommandData.get(), const_cast<const char*>(commands), initialSize);
mChunkedCommandPutOffset = initialSize;
mChunkedCommandRemainingSize = commandSize - initialSize;
return ChunkedCommandsResult::Consumed;
}
} // namespace dawn::wire