Files
nearby/cpp/core_v2/payload.h
T
Alexey Polyudov 7e19ffbab7 Release based on cl/313536507.
Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: I83ec7dee1a7ef6f4bdfd47482c94d03910525b7e
2020-06-04 10:06:31 -07:00

100 lines
3.4 KiB
C++

// Copyright 2020 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
//
// https://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 CORE_V2_PAYLOAD_H_
#define CORE_V2_PAYLOAD_H_
#include <cstdint>
#include <memory>
#include <utility>
#include "platform_v2/base/byte_array.h"
#include "platform_v2/base/input_stream.h"
#include "platform_v2/base/prng.h"
#include "platform_v2/public/file.h"
#include "absl/types/variant.h"
namespace location {
namespace nearby {
namespace connections {
// Payload is default-constructible, and moveable, but not copyable container
// that holds at most one instance of one of:
// ByteArray, InputStream, or InputFile.
class Payload {
public:
// Order of types in variant, and values in Type enum is important.
// Enum values must match respective variant types.
using Content =
absl::variant<absl::monostate, ByteArray, std::unique_ptr<InputStream>,
std::unique_ptr<InputFile>>;
enum class Type { kUnknown = 0, kBytes = 1, kStream = 2, kFile = 3 };
Payload(Payload&& other) = default;
~Payload() = default;
Payload& operator=(Payload&& other) = default;
// Create Payload from bytes, steam, or file. Payload is immutable.
Payload() : content_(absl::monostate()) {}
explicit Payload(ByteArray&& bytes) : content_(std::move(bytes)) {}
explicit Payload(const ByteArray& bytes) : content_(bytes) {}
explicit Payload(std::unique_ptr<InputStream> stream)
: content_(std::move(stream)) {}
explicit Payload(std::unique_ptr<InputFile> file)
: content_(std::move(file)) {}
// Returns ByteArray payload, if it has been defined, or empty ByteArray.
const ByteArray& AsBytes() const & {
static const ByteArray empty; // NOLINT: function-level static is OK.
auto* result = absl::get_if<ByteArray>(&content_);
return result ? *result : empty;
}
ByteArray&& AsBytes() && {
auto* result = absl::get_if<ByteArray>(&content_);
return result ? std::move(*result) : std::move(ByteArray());
}
// Returns InputStream* payload, if it has been defined, or nullptr.
InputStream* AsStream() const {
auto* result = absl::get_if<std::unique_ptr<InputStream>>(&content_);
return result ? result->get() : nullptr;
}
// Returns InputFile* payload, if it has been defined, or nullptr.
InputFile* AsFile() const {
auto* result = absl::get_if<std::unique_ptr<InputFile>>(&content_);
return result ? result->get() : nullptr;
}
// Returns Payload unique ID.
std::int64_t GetId() const { return id_; }
// Returns Payload type.
Type GetType() const { return type_; }
private:
static std::int64_t GenerateId() { return Prng().NextInt64(); }
Type FindType(const Content& content) const {
return static_cast<Type>(content_.index());
}
Content content_;
std::int64_t id_{GenerateId()};
Type type_{FindType(content_)};
};
} // namespace connections
} // namespace nearby
} // namespace location
#endif // CORE_V2_PAYLOAD_H_