Files
nearby/cpp/platform/public/file.h
T
Alexey Polyudov ce4807935e Roll forward to cl/338482889
Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: Ic2bdb234e89f3c5860d1b483dd4bce689f13d057
2020-10-22 11:30:33 -07:00

116 lines
4.0 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 PLATFORM_PUBLIC_FILE_H_
#define PLATFORM_PUBLIC_FILE_H_
#include <cstdint>
#include <memory>
#include <string>
#include "platform/api/input_file.h"
#include "platform/api/output_file.h"
#include "platform/api/platform.h"
#include "platform/base/byte_array.h"
#include "platform/base/exception.h"
#include "platform/base/input_stream.h"
#include "platform/base/output_stream.h"
namespace location {
namespace nearby {
class InputFile final {
public:
using Platform = api::ImplementationPlatform;
InputFile(PayloadId payload_id, std::int64_t size)
: impl_(Platform::CreateInputFile(payload_id, size)), id_(payload_id) {}
~InputFile() = default;
InputFile(InputFile&&) = default;
InputFile& operator=(InputFile&&) = default;
// Reads up to size bytes and returns as a ByteArray object wrapped by
// ExceptionOr.
// Returns Exception::kIo on error, or end of file.
ExceptionOr<ByteArray> Read(std::int64_t size) { return impl_->Read(size); }
// Returns a string that uniqely identifies this file.
std::string GetFilePath() const { return impl_->GetFilePath(); }
// Returns total size of this file in bytes.
std::int64_t GetTotalSize() const { return impl_->GetTotalSize(); }
// Disallows further reads from the file and frees system resources,
// associated with it.
Exception Close() { return impl_->Close(); }
// Returns a handle to the underlying input stream.
//
// Returned handle will remain valid even if InputFile is moved, for as long
// as original InputFile lifetime continues.
// Side effects of any non-const operation invoked for InputFile (such as
// Read, or Close will be observable through InputStream& handle, and vice
// versa.
InputStream& GetInputStream() { return *impl_; }
// Returns payload id of this file. The closest "file" equivalent is inode.
PayloadId GetPayloadId() const { return id_; }
private:
std::unique_ptr<api::InputFile> impl_;
PayloadId id_;
};
class OutputFile final {
public:
using Platform = api::ImplementationPlatform;
explicit OutputFile(PayloadId payload_id)
: impl_(Platform::CreateOutputFile(payload_id)), id_(payload_id) {}
~OutputFile() = default;
OutputFile(OutputFile&&) = default;
OutputFile& operator=(OutputFile&&) = default;
// Writes all data from ByteArray object to the underlying stream.
// Returns Exception::kIo on error, Exception::kSuccess otherwise.
Exception Write(const ByteArray& data) { return impl_->Write(data); }
// Ensures that all data written by previous calls to Write() is passed
// down to the applicable transport layer.
Exception Flush() { return impl_->Flush(); }
// Disallows further writes to the file and frees system resources,
// associated with it.
Exception Close() { return impl_->Close(); }
// Returns a handle to the underlying output stream.
//
// Returned handle will remain valid even if OutputFile is moved, for as long
// as original OutputFile lifetime continues.
// Side effects of any non-const operation invoked for OutputFile (such as
// Write, or Close will be observable through OutputStream& handle, and vice
// versa.
OutputStream& GetOutputStream() { return *impl_; }
// Returns payload id of this file. The closest "file" equivalent is inode.
PayloadId GetPayloadId() const { return id_; }
private:
std::unique_ptr<api::OutputFile> impl_;
PayloadId id_;
};
} // namespace nearby
} // namespace location
#endif // PLATFORM_PUBLIC_FILE_H_