slice_buffer.h

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// Copyright 2022 gRPC 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.
 
#ifndef GRPC_EVENT_ENGINE_SLICE_BUFFER_H
#define GRPC_EVENT_ENGINE_SLICE_BUFFER_H
 
#include <string.h>
 
#include <cstdint>
#include <string>
 
#include "absl/strings/string_view.h"
#include "absl/utility/utility.h"
 
#include <grpc/event_engine/internal/slice_cast.h>
#include <grpc/event_engine/slice.h>
#include <grpc/impl/codegen/slice.h>
#include <grpc/slice.h>
#include <grpc/slice_buffer.h>
#include <grpc/support/log.h>
#include <grpc/support/port_platform.h>
 
namespace grpc_event_engine {
namespace experimental {
 
class SliceBuffer {
 public:
  SliceBuffer() { grpc_slice_buffer_init(&slice_buffer_); }
  SliceBuffer(const SliceBuffer& other) = delete;
  SliceBuffer(SliceBuffer&& other) noexcept
      : slice_buffer_(other.slice_buffer_) {
    grpc_slice_buffer_init(&slice_buffer_);
    grpc_slice_buffer_swap(&slice_buffer_, &other.slice_buffer_);
  }
  ~SliceBuffer() { grpc_slice_buffer_destroy(&slice_buffer_); }
 
  SliceBuffer& operator=(const SliceBuffer&) = delete;
  SliceBuffer& operator=(SliceBuffer&& other) noexcept {
    grpc_slice_buffer_swap(&slice_buffer_, &other.slice_buffer_);
    return *this;
  }
 
  void Swap(SliceBuffer& other) {
    grpc_slice_buffer_swap(&slice_buffer_, &other.slice_buffer_);
  }
 
  void Append(Slice slice);
 
  size_t AppendIndexed(Slice slice);
 
  size_t Count() { return slice_buffer_.count; }
 
  void RemoveLastNBytes(size_t n) {
    grpc_slice_buffer_trim_end(&slice_buffer_, n, nullptr);
  }
 
  void MoveFirstNBytesIntoBuffer(size_t n, void* dst) {
    grpc_slice_buffer_move_first_into_buffer(&slice_buffer_, n, dst);
  }
 
  void MoveLastNBytesIntoSliceBuffer(size_t n, SliceBuffer& other) {
    grpc_slice_buffer_trim_end(&slice_buffer_, n, &other.slice_buffer_);
  }
 
  void MoveFirstNBytesIntoSliceBuffer(size_t n, SliceBuffer& other) {
    grpc_slice_buffer_move_first(&slice_buffer_, n, &other.slice_buffer_);
  }
 
  void Clear() { grpc_slice_buffer_reset_and_unref(&slice_buffer_); }
 
  Slice TakeFirst();
 
  void Prepend(Slice slice);
 
  Slice RefSlice(size_t index);
 
  const Slice& operator[](size_t index) const {
    return internal::SliceCast<Slice>(slice_buffer_.slices[index]);
  }
 
  Slice& MutableSliceAt(size_t index) const {
    return internal::SliceCast<Slice>(slice_buffer_.slices[index]);
  }
 
  size_t Length() const { return slice_buffer_.length; }
 
  grpc_slice_buffer* c_slice_buffer() { return &slice_buffer_; }
 
  // Returns a SliceBuffer that transfers slices into this new SliceBuffer,
  // leaving the input parameter empty.
  static SliceBuffer TakeCSliceBuffer(grpc_slice_buffer& slice_buffer) {
    return SliceBuffer(&slice_buffer);
  }
 
 private:
  // Transfers slices into this new SliceBuffer, leaving the parameter empty.
  // Does not take ownership of the slice_buffer argument.
  explicit SliceBuffer(grpc_slice_buffer* slice_buffer) {
    grpc_slice_buffer_init(&slice_buffer_);
    grpc_slice_buffer_swap(&slice_buffer_, slice_buffer);
  }
  grpc_slice_buffer slice_buffer_;
};
 
}  // namespace experimental
}  // namespace grpc_event_engine
 
#endif  // GRPC_EVENT_ENGINE_SLICE_BUFFER_H