object_rewriter.h

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// Copyright 2018 Google LLC
//
// 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 GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_STORAGE_OBJECT_REWRITER_H
#define GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_STORAGE_OBJECT_REWRITER_H
 
#include "google/cloud/storage/internal/raw_client.h"
#include "google/cloud/storage/version.h"
#include "google/cloud/internal/invoke_result.h"
 
namespace google {
namespace cloud {
namespace storage {
inline namespace STORAGE_CLIENT_NS {
struct RewriteProgress {
  std::uint64_t total_bytes_rewritten;
  std::uint64_t object_size;
  bool done;
};
 
class ObjectRewriter {
 public:
  ObjectRewriter(std::shared_ptr<internal::RawClient> client,
                 internal::RewriteObjectRequest request);
 
  StatusOr<RewriteProgress> Iterate();
 
  StatusOr<RewriteProgress> CurrentProgress() const {
    if (!last_error_.ok()) {
      return last_error_;
    }
    return progress_;
  }
 
  StatusOr<ObjectMetadata> Result() {
    return ResultWithProgressCallback([](StatusOr<RewriteProgress> const&) {});
  }
 
  template <
      typename Functor,
      typename std::enable_if<google::cloud::internal::is_invocable<
                                  Functor, StatusOr<RewriteProgress>>::value,
                              int>::type = 0>
  StatusOr<ObjectMetadata> ResultWithProgressCallback(Functor cb) {
    while (!progress_.done) {
      cb(Iterate());
    }
    if (!last_error_.ok()) {
      return last_error_;
    }
    return result_;
  }
 
  std::string const& token() const { return request_.rewrite_token(); }
 
 private:
  std::shared_ptr<internal::RawClient> client_;
  internal::RewriteObjectRequest request_;
  RewriteProgress progress_;
  ObjectMetadata result_;
  Status last_error_;
};
}  // namespace STORAGE_CLIENT_NS
}  // namespace storage
}  // namespace cloud
}  // namespace google
 
#endif  // GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_STORAGE_OBJECT_REWRITER_H