tools/fidl/fidlgen_llcpp/codegen/fragment_method_unownedresult.tmpl

{{/*
// Copyright 2021 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 "Method:UnownedResult:WireMessagingHeader" }}
{{- EnsureNamespace "" }}

template<>
class [[nodiscard]] {{ .WireUnownedResult }} final : public ::fidl::Status {
 public:
  {{- if .Transport.HasSyncClient }}
    {{- $args := (printf "::%s::UnownedClientEnd<%s> client_end" .Transport.Namespace .Protocol) }}
    {{- $args = (List $args "::fidl::internal::AnyBufferAllocator& allocator") }}
    {{- $args = (List $args (printf "%s* request" .WireTransactionalRequest)) }}
    explicit {{ .WireUnownedResult.Self }}({{ RenderParams $args }});
  {{- end }}

  {{- if .HasResponse }}
    explicit {{ .WireUnownedResult.Self }}({{ .WireTransactionalResponse }}* response)
        : fidl::Status(fidl::Status::Ok()), decoded_(response) {
      {{- if .HasApplicationError }}
      auto* raw_response = &decoded_.Value()->body;
      if (raw_response->result.is_err()) {
        result_ = fitx::error(raw_response->result.err());
      } else {
        result_ = fitx::ok({{ if .Result.ValueParameters }}&(raw_response->result.response()){{ end }});
      }
      {{- end }}
    }

    explicit {{ .WireUnownedResult.Self }}(
        ::fidl::unstable::DecodedMessage<{{ .WireTransactionalResponse }}>&& decoded,
        ::fidl::internal::MessageStorageViewBase* storage_view
    ) : fidl::Status(decoded) {
      if (decoded.ok()) {
        decoded_ = decoded.Take();
        {{- if .HasApplicationError }}
        auto* raw_response = &decoded_.Value()->body;
        if (raw_response->result.is_err()) {
          result_ = fitx::error(raw_response->result.err());
        } else if (raw_response->result.is_response()) {
          result_ = fitx::ok(
            {{- if .Result.ValueParameters -}}
              &(raw_response->result.response())
            {{- end -}}
          );
        }
        {{- end }}
      }
    }
  {{- end }}

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

  {{- if .HasWireResultBase }}
    {{ .WireResultBase }}* Unwrap() {
      {{- if .Result }}
        return &result_.value();
      {{- else }}
        ZX_ASSERT(ok());
        return &decoded_.Value()->body;
      {{- end }}
    }
    const {{ .WireResultBase }}* Unwrap() const {
      {{- if .Result }}
        return &result_.value();
      {{- else }}
        ZX_ASSERT(ok());
        return &decoded_.Value()->body;
      {{- end }}
    }

    {{ .WireResultBase }}& value() { return *Unwrap(); }
    const {{ .WireResultBase }}& value() const { return *Unwrap(); }

    {{ .WireResultBase }}* operator->() { return &value(); }
    const {{ .WireResultBase }}* operator->() const { return &value(); }

    {{ .WireResultBase }}& operator*() { return value(); }
    const {{ .WireResultBase }}& operator*() const { return value(); }
  {{- end }}

  {{- if .HasResponse }}
   private:
    ::fidl::internal::DecodedValue<{{ .WireTransactionalResponse }}> decoded_;
    {{- if and .Result .HasWireResultBase }}
      std::optional<{{ .WireResultBase }}> result_ = std::nullopt;
    {{- end }}
  {{- end }}
};

{{- end }}



{{- define "Method:UnownedResult:WireMessagingSource" }}
{{- if .Transport.HasSyncClient }}
{{- IfdefFuchsia -}}
{{- EnsureNamespace "" }}
{{- $args := (printf "::%s::UnownedClientEnd<%s> client_end" .Transport.Namespace .Protocol) }}
{{- $args = (List $args "::fidl::internal::AnyBufferAllocator& allocator") }}
{{- $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. */ -}}

  {{/* Allocate one buffer for both request/response (if applicable). */ -}}
  constexpr uint32_t buffer_size = ::fidl::SyncClientMethodBufferSizeInChannel<{{ .Marker }}>();
  ::fitx::result<::fidl::Error, ::fidl::BufferSpan> allocation = allocator.TryAllocate(buffer_size);
  if (!allocation.is_ok()) {
    SetStatus(allocation.error_value());
    return;
  }
  uint8_t* buffer = allocation->data;

  {{- if .HasResponse -}}
    {{/* TODO(fxbug.dev/85843): We should be able optimize this to just the max of
    the send/receive size, once Zircon channel calls guarantee that the
    send/receive buffers can overlap.

    For now, the invariant of SyncClientMethodBufferSizeInChannel is that it returns
    the sum of the request/response size, so we can index into it and get the
    address of the response buffer. */ -}}
    constexpr uint32_t request_byte_capacity = ::fidl::MaxSizeInChannel<
        {{ .WireTransactionalRequest }}, ::fidl::MessageDirection::kSending>();
    uint8_t* request_bytes = buffer;
    static_assert(buffer_size > request_byte_capacity);
    uint32_t response_byte_capacity = buffer_size - request_byte_capacity;
    uint8_t* response_bytes = &buffer[request_byte_capacity];
  {{- else }}
    uint32_t request_byte_capacity = buffer_size;
    uint8_t* request_bytes = buffer;
  {{- end }}

  ::fidl::unstable::UnownedEncodedMessage<{{ .WireTransactionalRequest }}> request_message(
      request_bytes, request_byte_capacity, request);
  auto& outgoing = request_message.GetOutgoingMessage();

  {{- if .HasResponse }}
    {{ .IncomingMessageHandleStorageForResponse }} handle_storage;
    ::fidl::unstable::DecodedMessage<{{ .WireTransactionalResponse }}> decoded{
        outgoing.Call(
            client_end.handle(),
            handle_storage.view(fidl::BufferSpan(response_bytes, response_byte_capacity))
        )
    };
    SetStatus(decoded);
    if (ok()) {
      decoded_ = decoded.Take();
    }

    {{- if .HasApplicationError }}
      if (ok()) {
        auto* raw_response = &decoded_.Value()->body;
        if (raw_response->result.is_err()) {
          result_ = fitx::error(raw_response->result.err());
        } else if (raw_response->result.is_response()) {
          result_ = fitx::ok(
            {{- if .Result.ValueParameters -}}
              &(raw_response->result.response())
            {{- end -}}
          );
        }
      }
    {{- end }}
  {{- else }}
    outgoing.Write(client_end.handle());
    SetStatus(outgoing);
  {{- end }}
}

{{- EndifFuchsia -}}
{{- end }}
{{- end }}