blob: 13e30e96857fc9749aa5fee95346692e248f1353 [file] [log] [blame]
// Copyright 2020 The Pigweed 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
// 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 <array>
#include <cstddef>
#include <span>
#include "pw_assert/assert.h"
#include "pw_status/status.h"
namespace pw::stream {
// General-purpose writer interface.
class Writer {
// There are no requirements around if or how a `Writer` should call Flush()
// at the time of object destruction. In general, do not assume a `Writer`
// will automatically call Flush when destroyed.
virtual ~Writer() = default;
// Write data to this stream Writer. If the writer runs out of resources, it
// will return Status::RESOURCE_EXHAUSTED. The derived class choses whether
// to do partial writes in this case, or abort the entire write operation.
// Derived classes should NOT try to override these public write methods.
// Instead, provide an implementation by overriding DoWrite().
Status Write(std::span<const std::byte> data) {
PW_DCHECK(data.empty() || != nullptr);
return DoWrite(data);
Status Write(const void* data, size_t size_bytes) {
return Write(std::span(static_cast<const std::byte*>(data), size_bytes));
// Flush any buffered data, finalizing all writes.
// Generally speaking, the scope that instantiates the concrete `Writer`
// class should be in charge of calling `Flush()`, and functions that only
// have access to the Writer interface should avoid calling this function.
virtual Status Flush() { return Status::OK; }
virtual Status DoWrite(std::span<const std::byte> data) = 0;
} // namespace pw::stream