1 // Copyright 2020 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <array> 17 #include <span> 18 19 #include "pw_assert/light.h" 20 #include "pw_hdlc/encoder.h" 21 #include "pw_rpc/channel.h" 22 #include "pw_stream/stream.h" 23 24 namespace pw::hdlc { 25 26 // Custom HDLC ChannelOutput class to write and read data through serial using 27 // the HDLC protocol. 28 // 29 // WARNING: This ChannelOutput is not thread-safe. If thread-safety is required, 30 // wrap this in a pw::rpc::SynchronizedChannelOutput. 31 class RpcChannelOutput : public rpc::ChannelOutput { 32 public: 33 // The RpcChannelOutput class does not own the buffer it uses to store the 34 // protobuf bytes. This buffer is specified at the time of creation along with 35 // a writer object to which will be used to write and send the bytes. RpcChannelOutput(stream::Writer & writer,std::span<std::byte> buffer,uint64_t address,const char * channel_name)36 constexpr RpcChannelOutput(stream::Writer& writer, 37 std::span<std::byte> buffer, 38 uint64_t address, 39 const char* channel_name) 40 : ChannelOutput(channel_name), 41 writer_(writer), 42 buffer_(buffer), 43 address_(address) {} 44 AcquireBuffer()45 std::span<std::byte> AcquireBuffer() override { return buffer_; } 46 SendAndReleaseBuffer(std::span<const std::byte> buffer)47 Status SendAndReleaseBuffer(std::span<const std::byte> buffer) override { 48 PW_DASSERT(buffer.data() == buffer_.data()); 49 if (buffer.empty()) { 50 return OkStatus(); 51 } 52 return hdlc::WriteUIFrame(address_, buffer, writer_); 53 } 54 55 private: 56 stream::Writer& writer_; 57 const std::span<std::byte> buffer_; 58 const uint64_t address_; 59 }; 60 61 // RpcChannelOutput with its own buffer. 62 // 63 // WARNING: This ChannelOutput is not thread-safe. If thread-safety is required, 64 // wrap this in a pw::rpc::SynchronizedChannelOutput. 65 template <size_t kBufferSize> 66 class RpcChannelOutputBuffer : public rpc::ChannelOutput { 67 public: RpcChannelOutputBuffer(stream::Writer & writer,uint64_t address,const char * channel_name)68 constexpr RpcChannelOutputBuffer(stream::Writer& writer, 69 uint64_t address, 70 const char* channel_name) 71 : ChannelOutput(channel_name), writer_(writer), address_(address) {} 72 AcquireBuffer()73 std::span<std::byte> AcquireBuffer() override { return buffer_; } 74 SendAndReleaseBuffer(std::span<const std::byte> buffer)75 Status SendAndReleaseBuffer(std::span<const std::byte> buffer) override { 76 PW_DASSERT(buffer.data() == buffer_.data()); 77 if (buffer.empty()) { 78 return OkStatus(); 79 } 80 return hdlc::WriteUIFrame(address_, buffer, writer_); 81 } 82 83 private: 84 stream::Writer& writer_; 85 std::array<std::byte, kBufferSize> buffer_; 86 const uint64_t address_; 87 }; 88 89 } // namespace pw::hdlc 90