blob: ecae939225bdef9b530ea6618d63283ad9d1f1b5 [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 <cstdint>
#include <span>
#include "pw_assert/assert.h"
#include "pw_status/status.h"
namespace pw::rpc {
namespace internal {
class BaseServerWriter;
} // namespace internal
class ChannelOutput {
// Creates a channel output with the provided name. The name is used for
// logging only.
constexpr ChannelOutput(const char* name) : name_(name) {}
virtual ~ChannelOutput() = default;
constexpr const char* name() const { return name_; }
// Acquire a buffer into which to write an outgoing RPC packet.
virtual std::span<std::byte> AcquireBuffer() = 0;
// Sends the contents of the buffer from AcquireBuffer().
virtual void SendAndReleaseBuffer(size_t size) = 0;
const char* name_;
class Channel {
static constexpr uint32_t kUnassignedChannelId = 0;
// Creates a dynamically assignable channel without a set ID or output.
constexpr Channel() : id_(kUnassignedChannelId), output_(nullptr) {}
// Creates a channel with a static ID. The channel's output can also be
// static, or it can set to null to allow dynamically opening connections
// through the channel.
template <uint32_t id>
constexpr static Channel Create(ChannelOutput* output) {
static_assert(id != kUnassignedChannelId, "Channel ID cannot be 0");
return Channel(id, output);
constexpr uint32_t id() const { return id_; }
constexpr bool assigned() const { return id_ != kUnassignedChannelId; }
constexpr Channel(uint32_t id, ChannelOutput* output)
: id_(id), output_(output) {
PW_CHECK_UINT_NE(id, kUnassignedChannelId);
ChannelOutput& output() const {
return *output_;
uint32_t id_;
ChannelOutput* output_;
} // namespace pw::rpc