| // Copyright 2021 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 |
| // |
| // 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. |
| #pragma once |
| |
| #include <array> |
| |
| #include "pw_function/function.h" |
| #include "pw_status/status.h" |
| #include "pw_stream/stream.h" |
| #include "pw_sync/lock_annotations.h" |
| #include "pw_sync/mutex.h" |
| #include "pw_transfer/internal/client_context.h" |
| #include "pw_transfer/transfer.raw_rpc.pb.h" |
| #include "pw_work_queue/work_queue.h" |
| |
| namespace pw::transfer { |
| |
| class Client { |
| public: |
| using CompletionFunc = Function<void(Status)>; |
| |
| // Initializes a transfer client on a specified RPC client and channel. |
| // Transfers are processed on a work queue so as not to block any RPC threads. |
| // The work queue does not have to be unique to the transfer client; it can be |
| // shared with other modules (including additional transfer clients). |
| // |
| // As data is processed within the work queue's context, the original RPC |
| // messages received by the transfer service are not available. Therefore, |
| // the transfer client requires an additional buffer where transfer data can |
| // stored during the context switch. |
| // |
| // The size of this buffer is the largest amount of bytes that can be sent |
| // within a single transfer chunk (read or write), excluding any transport |
| // layer overhead. Not all of this size is used to send data -- there is |
| // additional overhead in the pw_rpc and pw_transfer protocols (typically |
| // ~22B/chunk). |
| // |
| // An optional max_bytes_to_receive argument can be provided to set the |
| // default number of data bytes the client will request from the server at a |
| // time. If not provided, this defaults to the size of the data buffer. A |
| // larger value can make transfers more efficient as it minimizes the |
| // back-and-forth between client and server; however, it also increases the |
| // impact of packet loss, potentially requiring larger retransmissions to |
| // recover. |
| Client(rpc::Client& rpc_client, |
| uint32_t channel_id, |
| work_queue::WorkQueue& work_queue, |
| ByteSpan transfer_data_buffer, |
| size_t max_bytes_to_receive = 0) |
| : client_(rpc_client, channel_id), |
| work_queue_(work_queue), |
| max_parameters_(max_bytes_to_receive > 0 ? max_bytes_to_receive |
| : transfer_data_buffer.size(), |
| transfer_data_buffer.size()), |
| chunk_data_buffer_(transfer_data_buffer) {} |
| |
| // Begins a new read transfer for the given transfer ID. The data read from |
| // the server is written to the provided writer. Returns OK if the transfer is |
| // successfully started. When the transfer finishes (successfully or not), the |
| // completion callback is invoked with the overall status. |
| Status Read( |
| uint32_t transfer_id, |
| stream::Writer& output, |
| CompletionFunc&& on_completion, |
| chrono::SystemClock::duration timeout = cfg::kDefaultChunkTimeout); |
| |
| // Begins a new write transfer for the given transfer ID. Data from the |
| // provided reader is sent to the server. When the transfer finishes |
| // (successfully or not), the completion callback is invoked with the overall |
| // status. |
| Status Write( |
| uint32_t transfer_id, |
| stream::Reader& input, |
| CompletionFunc&& on_completion, |
| chrono::SystemClock::duration timeout = cfg::kDefaultChunkTimeout); |
| |
| private: |
| using Transfer = pw_rpc::raw::Transfer; |
| using ClientContext = internal::ClientContext; |
| |
| enum Type : bool { kRead, kWrite }; |
| |
| Status StartNewTransfer(uint32_t transfer_id, |
| Type type, |
| stream::Stream& stream, |
| CompletionFunc&& on_completion, |
| chrono::SystemClock::duration timeout); |
| |
| ClientContext* GetTransferById(uint32_t transfer_id); |
| |
| // Function called when a chunk is received, from the context of the RPC |
| // client thread. |
| void OnChunk(ConstByteSpan data, Type type); |
| |
| Transfer::Client client_; |
| work_queue::WorkQueue& work_queue_; |
| |
| rpc::RawClientReaderWriter read_stream_; |
| rpc::RawClientReaderWriter write_stream_; |
| |
| // TODO(frolv): Make this size configurable. |
| std::array<ClientContext, 1> transfer_contexts_ |
| PW_GUARDED_BY(transfer_context_mutex_); |
| sync::Mutex transfer_context_mutex_; |
| |
| internal::TransferParameters max_parameters_; |
| internal::ChunkDataBuffer chunk_data_buffer_; |
| }; |
| |
| } // namespace pw::transfer |