WriteFileHandler.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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.
 */
 
#pragma once
 
#include <vrs/ErrorCode.h>
#include <vrs/FileHandler.h>
#include <vrs/os/CompilerAttributes.h>
 
namespace vrs {
 
class WriteFileHandler : public FileHandler {
 public:
  WriteFileHandler() = default;
 
  static unique_ptr<WriteFileHandler> make(const string& fileHandlerName);
 
  virtual int create(const FileSpec& spec) {
    return spec.chunks.empty() ? INVALID_FILE_SPEC : create(spec.chunks.front(), spec.extras);
  }
 
  virtual int create(const string& newFilePath, const FileSpec::Extras& options = {}) = 0;
 
  virtual int createSplitFile(const FileSpec& spec, const string& initialFilePath) {
    // create the (first) user record chunk
    if (spec.chunks.size() == 1) {
      return create(spec.chunks.front() + "_1", spec.extras);
    } else {
      return create(initialFilePath, spec.extras);
    }
  }
 
  virtual void addSplitHead(MAYBE_UNUSED FileSpec& inOutSpec) {}
 
  virtual bool reopenForUpdatesSupported() const = 0;
 
  virtual int reopenForUpdates() = 0;
 
  bool isReadOnly() const override = 0;
 
  virtual int write(const void* buffer, size_t length) = 0;
  template <typename T, std::enable_if_t<std::is_trivially_copyable<T>::value, int> = 0>
  int write(const T& object) {
    return write(&object, sizeof(object));
  }
 
  virtual int overwrite(const void* buffer, size_t length) = 0;
  template <typename T, std::enable_if_t<std::is_trivially_copyable<T>::value, int> = 0>
  int overwrite(const T& object) {
    return overwrite(&object, sizeof(object));
  }
 
  virtual int addChunk() = 0;
  virtual int truncate() = 0;
  virtual bool getCurrentChunk(string& outChunkPath, size_t& outChunkIndex) const = 0;
};
 
} // namespace vrs