text: // 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 <cstring>
  
  #include "pw_bytes/span.h"
  #include "pw_rpc/internal/call_context.h"
  #include "pw_rpc/internal/server_call.h"
  #include "pw_rpc/method_type.h"
  
  namespace pw::rpc::internal::test {
  
  // Fake server reader/writer classes for testing use. These also serve as a
  // model for how the RPC implementations (raw, pwpb, Nanopb) structure their
  // reader/writer classes.
  //
  // Readers/writers use an unusual inheritance hierarchy. Rather than having the
  // ServerReaderWriter inherit from both the Reader and Writer classes, the
  // readers and writers inherit from it, but hide the unsupported functionality.
  // A ReaderWriter defines conversions to Reader and Writer, so it acts as if it
  // inherited from both. This approach is unusual but necessary to have all
  // classes use a single IntrusiveList::Item base and to avoid virtual methods or
  // virtual inheritance.
  //
  // Call's public API is intended for rpc::Server, so hide the public methods
  // with private inheritance.
  class FakeServerReaderWriter : private internal::ServerCall {
   public:
    constexpr FakeServerReaderWriter() = default;
  
    // On a real reader/writer, this constructor would not be exposed.
    FakeServerReaderWriter(const CallContext& context,
                           MethodType type = MethodType::kBidirectionalStreaming)
        : ServerCall(context, type) {}
  
    FakeServerReaderWriter(FakeServerReaderWriter&&) = default;
    FakeServerReaderWriter& operator=(FakeServerReaderWriter&&) = default;
  
    // Pull in protected functions from the hidden Call base as needed.
    using Call::active;
    using Call::set_on_error;
    using Call::set_on_next;
    using ServerCall::set_on_client_stream_end;
  
    Status Finish(Status status = OkStatus()) {
      return CloseAndSendResponse(status);
    }
  
    using Call::Write;
  
    // Expose a few additional methods for test use.
    ServerCall& as_server_call() { return *this; }
  };
  
  class FakeServerWriter : private FakeServerReaderWriter {
   public:
    constexpr FakeServerWriter() = default;
  
    FakeServerWriter(const CallContext& context)
        : FakeServerReaderWriter(context, MethodType::kServerStreaming) {}
    FakeServerWriter(FakeServerWriter&&) = default;
  
    // Common reader/writer functions.
    using FakeServerReaderWriter::active;
    using FakeServerReaderWriter::Finish;
    using FakeServerReaderWriter::set_on_error;
    using FakeServerReaderWriter::Write;
  
    // Functions for test use.
    using FakeServerReaderWriter::as_server_call;
  };
  
  class FakeServerReader : private FakeServerReaderWriter {
   public:
    constexpr FakeServerReader() = default;
  
    FakeServerReader(const CallContext& context)
        : FakeServerReaderWriter(context, MethodType::kClientStreaming) {}
  
    FakeServerReader(FakeServerReader&&) = default;
  
    using FakeServerReaderWriter::active;
    using FakeServerReaderWriter::as_server_call;
  };
  
  }  // namespace pw::rpc::internal::test
  