tools/fidl/fidlgen_cpp/codegen/driver/fragment_method_unownedresult.tmpl

{{/*
// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
*/}}

{{- define "driver/Method:UnownedResult:MessagingHeader" }}
{{- EnsureNamespace "" }}

{{ if .WireResultUnwrapType -}}
template<>
struct {{ .WireResultUnwrap }} {
  using Type = {{ .WireResultUnwrapType }};
};
{{- end }}

{{/* TODO(fxbug.dev/105375): This type should probably actually just be called
* WireResult since it owns and fdf::Arena and uses DecodedValue to own the
* handles in the decoded message. */}}
template<>
class [[nodiscard]] {{ .WireUnownedResult }} final : public {{ .BaseWireResult }} {
 public:
  {{- if .Transport.HasSyncClient }}
    {{- $args := (printf "%s client_end" .Protocol.UnownedClientEnd) }}
    {{- $args = (List $args "const ::fdf::Arena& arena") }}
    {{- $args = (List $args (printf "%s* request" .WireTransactionalRequest)) }}
    explicit {{ .WireUnownedResult.Self }}({{ RenderParams $args }});
  {{- end }}

  {{- if .HasResponsePayload }}
    explicit {{ .WireUnownedResult.Self }}({{ .WireResponse }}* response)
        : {{ .BaseWireResult }}(fidl::Status::Ok()), decoded_(response) {
      ExtractValueFromDecoded(decoded_.pointer());
    }

    explicit {{ .WireUnownedResult.Self }}(
      ::fit::result<::fidl::Error, ::fidl::DecodedValue<{{ .WireResponse }}>>&& decoded,
      ::fidl::internal::MessageStorageViewBase* storage_view
    ) : {{ .BaseWireResult }}(::fidl::internal::StatusFromResult(decoded)),
        arena_(::fidl::internal::TakeDriverArenaFromStorage(storage_view)) {
      if (decoded.is_ok()) {
        decoded_ = std::move(decoded.value());
        ExtractValueFromDecoded(decoded_.pointer());
      }
    }
  {{- else }}
    explicit {{ .WireUnownedResult.Self }}(
        ::fit::result<::fidl::Error>&& decoded,
        ::fidl::internal::MessageStorageViewBase* storage_view
    ) : {{ .BaseWireResult }}(::fidl::internal::StatusFromResult(decoded)) {}
  {{- end }}

  explicit {{ .WireUnownedResult.Self }}(const ::fidl::Status& result) : {{ .BaseWireResult }}(result) {}
  {{ .WireUnownedResult.Self }}({{ .WireUnownedResult.Self }}&&) = default;
  {{ .WireUnownedResult.Self }}(const {{ .WireUnownedResult.Self }}&) = delete;
  {{ .WireUnownedResult.Self }}& operator=({{ .WireUnownedResult.Self }}&&) = default;
  {{ .WireUnownedResult.Self }}* operator=(const {{ .WireUnownedResult.Self }}&) = delete;
  ~{{ .WireUnownedResult.Self }}() = default;

  {{- if .HasResponse }}
    fdf::Arena& arena() {
      ZX_ASSERT(ok());
      return arena_;
    }

   private:
    ::fdf::Arena arena_{nullptr};
    {{- if .HasResponsePayload }}
      ::fidl::DecodedValue<{{ .WireResponse }}> decoded_;
    {{- end }}
  {{- end }}
};
{{- end }}




{{- define "driver/Method:UnownedResult:MessagingSource" }}
{{- if .Transport.HasSyncClient }}
{{- IfdefFuchsia -}}
{{- EnsureNamespace "" }}
{{- $args := (printf "%s client_end" .Protocol.UnownedClientEnd) }}
{{- $args = (List $args "const ::fdf::Arena& arena") }}
{{- $args = (List $args (printf "%s* request" .WireTransactionalRequest)) }}
{{ .WireUnownedResult }}::{{ .WireUnownedResult.Self }}({{ RenderParams $args }}) {
  {{/* TODO(fxbug.dev/86367): Factor out common buffer allocation logic once we have other instances
  of this pattern. */ -}}

  constexpr uint32_t buffer_size =
    ::fidl::MaxSizeInChannel<{{ .WireTransactionalRequest }}, ::fidl::MessageDirection::kSending>();
  uint8_t* buffer = static_cast<uint8_t*>(arena.Allocate(buffer_size));

  ::fidl::internal::UnownedEncodedMessage<{{ .WireTransactionalRequest }}, fidl::internal::DriverTransport> request_message(
      buffer, buffer_size, request);
  auto& outgoing = request_message.GetOutgoingMessage();

  {{- if .HasResponse }}
    {{ .IncomingMessageStorageForResponse }} response_storage;
    ::fidl::CallOptions call_options = {
        .outgoing_transport_context =
            ::fidl::internal::OutgoingTransportContext::Create<fidl::internal::DriverTransport>(
                arena.get()),
    };
    ::fit::result decoded = ::fidl::internal::InplaceDecodeTransactionalResponse<{{ .Marker }}>(
        outgoing.Call(client_end.handle(), response_storage.view(), std::move(call_options))
    );
    SetStatus(::fidl::internal::StatusFromResult(decoded));
    {{- if .HasResponsePayload }}
      if (ok()) {
        decoded_ = std::move(decoded.value());
        ExtractValueFromDecoded(decoded_.pointer());
      }
    {{- end }}
    arena_ = std::move(response_storage.arena);
  {{- else }}
    ::fidl::WriteOptions write_options = {
        .outgoing_transport_context =
            ::fidl::internal::OutgoingTransportContext::Create<fidl::internal::DriverTransport>(
                arena.get()),
    };
    outgoing.Write(client_end.handle(), std::move(write_options));
    SetStatus(outgoing);
  {{- end }}
}
{{- EndifFuchsia -}}
{{- end }}
{{- end }}