tools/fidl/fidlgen_llcpp/codegen/fragment_struct.tmpl.go

// Copyright 2018 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.

package codegen

const fragmentStructTmpl = `
{{- define "StructForwardDeclaration" }}
{{ EnsureNamespace . }}
struct {{ .Name }};
{{- end }}

{{/* TODO(fxbug.dev/36441): Remove __Fuchsia__ ifdefs once we have non-Fuchsia
     emulated handles for C++. */}}
{{- define "StructDeclaration" }}
{{ EnsureNamespace . }}
{{ if .IsResourceType }}
{{- IfdefFuchsia -}}
{{- end }}
extern "C" const fidl_type_t {{ .CodingTableType }};
{{ .Docs }}
struct {{ .Name }} {
  static constexpr const fidl_type_t* Type = &{{ .CodingTableType }};
  static constexpr uint32_t MaxNumHandles = {{ .MaxHandles }};
  static constexpr uint32_t PrimarySize = {{ .InlineSize }};
  [[maybe_unused]]
  static constexpr uint32_t MaxOutOfLine = {{ .MaxOutOfLine }};
  static constexpr bool HasPointer = {{ .HasPointer }};

  {{- range .Members }}
{{ "" }}
    {{- .Docs }}
    {{ .Type }} {{ .Name }} = {};
  {{- end }}

  {{- if .IsResourceType }}

  void _CloseHandles();
  {{- end }}

  class UnownedEncodedMessage final {
   public:
    UnownedEncodedMessage(uint8_t* backing_buffer, uint32_t backing_buffer_size, {{ .Name }}* value)
      : UnownedEncodedMessage(::fidl::internal::IovecBufferSize, backing_buffer, backing_buffer_size, value) {}
    UnownedEncodedMessage(uint32_t iovec_capacity, uint8_t* backing_buffer, uint32_t backing_buffer_size,
      {{ .Name }}* value)
      : message_(::fidl::OutgoingMessage::ConstructorArgs{
          .iovecs = iovecs_,
          .iovec_capacity = iovec_capacity,
    {{- if gt .MaxHandles 0 }}
          .handles = handles_,
          .handle_capacity = std::min(ZX_CHANNEL_MAX_MSG_HANDLES, MaxNumHandles),
    {{- end }}
          .backing_buffer = backing_buffer,
          .backing_buffer_capacity = backing_buffer_size,
        }) {
      ZX_ASSERT(iovec_capacity <= std::size(iovecs_));
      message_.Encode<{{ .Name }}>(value);
    }
    UnownedEncodedMessage(const UnownedEncodedMessage&) = delete;
    UnownedEncodedMessage(UnownedEncodedMessage&&) = delete;
    UnownedEncodedMessage* operator=(const UnownedEncodedMessage&) = delete;
    UnownedEncodedMessage* operator=(UnownedEncodedMessage&&) = delete;

    zx_status_t status() const { return message_.status(); }
{{- IfdefFuchsia -}}
    const char* status_string() const { return message_.status_string(); }
{{- EndifFuchsia -}}
    bool ok() const { return message_.status() == ZX_OK; }
    std::string FormatDescription() const { return message_.FormatDescription(); }
    const char* lossy_description() const { return message_.lossy_description(); }
    const ::fidl::Result& error() const { return message_.error(); }

    ::fidl::OutgoingMessage& GetOutgoingMessage() { return message_; }

   private:
    ::fidl::internal::IovecBuffer iovecs_;
    {{- if gt .MaxHandles 0 }}
      zx_handle_disposition_t handles_[std::min(ZX_CHANNEL_MAX_MSG_HANDLES, MaxNumHandles)];
    {{- end }}
    ::fidl::OutgoingMessage message_;
  };

  class OwnedEncodedMessage final {
   public:
    explicit OwnedEncodedMessage({{ .Name }}* value)
      : message_(1u, backing_buffer_.data(), backing_buffer_.size(), value) {}
    // Internal constructor.
    explicit OwnedEncodedMessage(::fidl::internal::AllowUnownedInputRef allow_unowned, {{ .Name }}* value)
      : message_(::fidl::internal::IovecBufferSize, backing_buffer_.data(), backing_buffer_.size(), value) {}
    OwnedEncodedMessage(const OwnedEncodedMessage&) = delete;
    OwnedEncodedMessage(OwnedEncodedMessage&&) = delete;
    OwnedEncodedMessage* operator=(const OwnedEncodedMessage&) = delete;
    OwnedEncodedMessage* operator=(OwnedEncodedMessage&&) = delete;

    zx_status_t status() const { return message_.status(); }
{{- IfdefFuchsia -}}
    const char* status_string() const { return message_.status_string(); }
{{- EndifFuchsia -}}
    bool ok() const { return message_.ok(); }
    std::string FormatDescription() const { return message_.FormatDescription(); }
    const char* lossy_description() const { return message_.lossy_description(); }
    const ::fidl::Result& error() const { return message_.error(); }

    ::fidl::OutgoingMessage& GetOutgoingMessage() { return message_.GetOutgoingMessage(); }

   private:
    {{ .BackingBufferType }} backing_buffer_;
    UnownedEncodedMessage message_;
  };

  class DecodedMessage final : public ::fidl::internal::DecodedMessageBase<{{ .Name }}> {
   public:
    using DecodedMessageBase<{{ .Name }}>::DecodedMessageBase;

    DecodedMessage(uint8_t* bytes, uint32_t byte_actual, zx_handle_info_t* handles = nullptr,
                   uint32_t handle_actual = 0)
        : DecodedMessageBase(
              ::fidl::IncomingMessage(bytes, byte_actual, handles, handle_actual,
                  ::fidl::IncomingMessage::kSkipMessageHeaderValidation)) {}

    DecodedMessage(const fidl_incoming_msg_t* c_msg)
        : DecodedMessage(reinterpret_cast<uint8_t*>(c_msg->bytes), c_msg->num_bytes,
                         c_msg->handles, c_msg->num_handles) {}

    {{- if .IsResourceType }}
    ~DecodedMessage() {
      if (ok() && (PrimaryObject() != nullptr)) {
        PrimaryObject()->_CloseHandles();
      }
    }
    {{- end }}

    {{ .Name }}* PrimaryObject() {
      ZX_DEBUG_ASSERT(ok());
      return reinterpret_cast<{{ .Name }}*>(bytes());
    }

    // Release the ownership of the decoded message. That means that the handles won't be closed
    // When the object is destroyed.
    // After calling this method, the |DecodedMessage| object should not be used anymore.
    void ReleasePrimaryObject() { ResetBytes(); }
  };
};
{{- if .IsResourceType }}
{{- EndifFuchsia -}}
{{- end }}
{{- end }}

{{/* TODO(fxbug.dev/36441): Remove __Fuchsia__ ifdefs once we have non-Fuchsia
     emulated handles for C++. */}}
{{- define "StructDefinition" }}
{{ EnsureNamespace "" }}
{{ if .IsResourceType }}
{{- IfdefFuchsia -}}
void {{ . }}::_CloseHandles() {
  {{- range .Members }}
    {{- CloseHandles . false false }}
  {{- end }}
}
{{- EndifFuchsia -}}
{{- end }}
{{- end }}

{{/* TODO(fxbug.dev/36441): Remove __Fuchsia__ ifdefs once we have non-Fuchsia
     emulated handles for C++. */}}
{{- define "StructTraits" }}
{{ if .IsResourceType }}
{{- IfdefFuchsia -}}
{{- end }}
template <>
struct IsFidlType<{{ . }}> : public std::true_type {};
template <>
struct IsStruct<{{ . }}> : public std::true_type {};
static_assert(std::is_standard_layout_v<{{ . }}>);
{{- $struct := . }}
{{- range .Members }}
static_assert(offsetof({{ $struct }}, {{ .Name }}) == {{ .Offset }});
{{- end }}
static_assert(sizeof({{ . }}) == {{ . }}::PrimarySize);
{{- if .IsResourceType }}
{{- EndifFuchsia -}}
{{- end }}
{{- end }}
`