tools/fidl/fidlmerge/examples/ostream

{{/*

This is an example fidlmerge template. It generates .h and .cc files for the
ostream operator<< overloads required to print the types generated by fidlmerge
for FIDL enums, structs and unions.

NOTE: This template uses some indenting capabilities that aren't currently
implemented in the tree.

NOTE: This template generates a "#pragma once", which should be replaced by
an #ifndef guard to conform to the style guide. scripts/git-file-format will do
this automatically.

*/}}


{{/* Produces the copyright messages for a file header. */}}
{{/* TODO: variable copyright year. */}}
{{- define "FileHeader" -}}
// 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.
//
// WARNING: This file is machine generated by fidlmerge.
{{- end }}


{{- define "ThisFidlInclude" -}}
    #include <{{- range .Name.Parts}}{{ . }}/{{ end }}cpp/fidl.h>
{{ end }}


{{- define "IncludeHeader" }}
    {{- template "FileHeader" }}

#pragma once

{{ template "ThisFidlInclude" . }}
    {{- range .Name.Parts }}
namespace {{ . }} {
    {{- end }}

// Because the FIDL compiler back end generates simple ostream formatters for
// enums, WrapEnum is used to allow for alternative formatters.
// e.g. os << WrapEnum(enum_value);
template <typename T>
struct WrapEnum {
  WrapEnum(T actual) : actual_(actual) {}
  T actual_;
};
{{ end }}


{{- define "NamespaceClose" }}
{{/* keep the newline */}}
    {{- range .Name.PartsReversed }}
} // namespace {{ . }}
    {{- end }}
{{- end }}


{{/* Produces a C++ expression for a types.EncodedCompoundIdentifier. */}}
{{/* The expression is qualified for use in the subject namespace. */}}
{{- define "Id" }}
    {{- if isLocal . }}
        {{- .Parts.Name }}
    {{- else }}
        {{- template "QualifiedId" . }}
    {{- end }}
{{- end }}


{{- define "EnumWriterDecls" }}
    {{- range .Enums }}
std::ostream& operator<<(std::ostream& os, const WrapEnum<{{ .Name.Parts.Name }}>& value);
    {{- end }}
{{- end }}


{{- define "StructWriterDecls" }}
    {{- range .Structs }}
std::ostream& operator<<(std::ostream& os, const {{ .Name.Parts.Name }}& value);
    {{- end }}
{{- end }}


{{- define "UnionWriterDecls" }}
    {{- range .Unions }}
std::ostream& operator<<(std::ostream& os, const {{ .Name.Parts.Name }}& value);
    {{- end }}
{{- end }}


{{- define "ImplementationHeader" }}
    {{- template "FileHeader" }}

// TODO: Fix this include to reference the generated include file.
#include "..."

#include "lib/fostr/fidl_types.h"
{{/* keep the newline */}}
    {{- range .Name.Parts }}
namespace {{ . }} {
    {{- end }}

template <typename T>
std::ostream& operator<<(std::ostream& os, const std::unique_ptr<T>& value) {
  if (!value) {
    return os << "<null>";
  }

  return os << *value;
}
{{/* keep the newline */}}
{{- end }}


{{- define "EnumWriterDefs" }}
    {{- range .Enums }}
        {{- $type_name := .Name.Parts.Name }}
std::ostream& operator<<(std::ostream& os, const WrapEnum<{{ .Name.Parts.Name }}>& value) {
  switch (value.actual_) {
        {{- range .Members }}
    case {{ $type_name }}::{{ .Name }}:
      return os << "{{ toFriendlyCase .Name }}";
        {{- end }}
  }

  return os;
}
{{/* keep the newline */}}
    {{- end }}
{{- end }}


{{- define "StructWriterDefs" }}
    {{- range .Structs }}

std::ostream& operator<<(std::ostream& os, const {{ .Name.Parts.Name }}& value) {
  os << fostr::Indent;
        {{- range .Members }}
            {{- if eq .Type.Kind "identifier" }}
                {{- if eq (declType .Type.Identifier) "enum" }}
  os << fostr::NewLine << "{{ .Name }}: " << WrapEnum<{{ template "Id" .Type.Identifier }}>(value.{{ .Name }});
                {{- else }}
  os << fostr::NewLine << "{{ .Name }}: " << value.{{ .Name }};
                {{- end }}
            {{- else }}
  os << fostr::NewLine << "{{ .Name }}: " << value.{{ .Name }};
            {{- end }}
        {{- end }}
  return os << fostr::Outdent;
}
    {{- end }}
{{- end }}


{{- define "UnionWriterDefs" }}
    {{- range .Unions }}

std::ostream& operator<<(std::ostream& os, const {{ .Name.Parts.Name }}& value) {
  switch (value.Which()) {
        {{- $type_name := .Name.Parts.Name }}
        {{- range .Members }}
    case {{ $type_name }}::Tag::k{{ toUpperCamelCase .Name }}:
            {{- if eq .Type.Kind "identifier" }}
                {{- if eq (declType .Type.Identifier) "enum" }}
      return os << "{{ toSnakeCase .Name }} " << WrapEnum<{{ template "Id" .Type.Identifier }}>(value.{{ toSnakeCase .Name }}());
                {{- else }}
      return os << "{{ toSnakeCase .Name }} " << value.{{ toSnakeCase .Name }}();
                {{- end }}
            {{- else }}
      return os << "{{ toSnakeCase .Name }} " << value.{{ toSnakeCase .Name }}();
            {{- end }}
        {{- end }}
    case {{ $type_name }}::Tag::Invalid:
      return os << "<invalid union>";
  }

  return os;
}
    {{- end }}
{{- end }}


{{- define "IncludeFile" }}
    {{- template "IncludeHeader" . }}
    {{- template "EnumWriterDecls" . }}
    {{- template "StructWriterDecls" . }}
    {{- template "UnionWriterDecls" . }}
    {{- template "NamespaceClose" . }}
{{- end }}


{{- define "ImplementationFile" }}
    {{- template "ImplementationHeader" . }}
    {{- template "EnumWriterDefs" . }}
    {{- template "StructWriterDefs" . }}
    {{- template "UnionWriterDefs" . }}
    {{- template "NamespaceClose" . }}
{{- end }}


{{- define "Main" }}
    {{- $include_path := .Output ".h" }}
    {{- $implementation_path := .Output ".cc" }}
    {{ .Generate $include_path "IncludeFile" . }}
    {{ .Generate $implementation_path "ImplementationFile" . }}
{{end}}