lib/src/header_parser/sub_parsers/structdecl_parser.dart

// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:ffi';

import 'package:ffigen/src/code_generator.dart';
import 'package:logging/logging.dart';

import '../clang_bindings/clang_bindings.dart' as clang;
import '../includer.dart';
import '../utils.dart';

var _logger = Logger('parser:structdecl_parser');

/// Temporarily holds a struc before its returned by [parseStructDeclaration].
Struc _struc;

/// Parses a struct declaration.
Struc parseStructDeclaration(
  Pointer<clang.CXCursor> cursor, {

  /// Optionally provide name (useful in case struct is inside a typedef).
  String name,

  /// Option to override shouldInclude methods. (Useful in case of extracting
  /// structs when they are passed/returned by an included function.)
  ///
  /// Check if binding is not already included before setting this to true.
  bool doInclude = false,
}) {
  _struc = null;
  final structName = name ?? cursor.spelling();

  if (structName == '') {
    _logger.finest('unnamed structure or typedef structure declaration');
    return null;
  } else if (doInclude || shouldIncludeStruct(structName)) {
    _logger.fine(
        '++++ Adding Structure: structName: ${structName}, ${cursor.completeStringRepr()}');

    final members = _getMembers(cursor, structName);
    _struc = Struc(
      dartDoc: getCursorDocComment(cursor),
      name: structName,
      members: members,
    );
  }

  return _struc;
}

List<Member> _members;
List<Member> _getMembers(Pointer<clang.CXCursor> cursor, String structName) {
  _members = [];
  nestedStructMember = false;
  unimplementedMemberType = false;

  final resultCode = clang.clang_visitChildren_wrap(
      cursor,
      Pointer.fromFunction(
          _structMembersVisitor, clang.CXChildVisitResult.CXChildVisit_Break),
      nullptr);

  visitChildrenResultChecker(resultCode);

  // Returning null to exclude the struct members as it has a struct by value field.
  if (nestedStructMember) {
    _logger.fine(
        '---- Removed Struct members, reason: struct has struct members ${cursor.completeStringRepr()}');
    _logger.warning(
        "Removed All Struct Members from '$structName', Nested Structures not supported.");
    return null;
  } else if (unimplementedMemberType) {
    _logger.fine(
        '---- Removed Struct members, reason: member with unimplementedtype ${cursor.completeStringRepr()}');
    _logger.warning(
        "Removed All Struct Members from '$structName', struct member has an unsupported type.");
    return null;
  }

  return _members;
}

bool nestedStructMember = false;
bool unimplementedMemberType = false;

/// Visitor for the struct cursor [CXCursorKind.CXCursor_StructDecl].
///
/// Child visitor invoked on struct cursor.
int _structMembersVisitor(Pointer<clang.CXCursor> cursor,
    Pointer<clang.CXCursor> parent, Pointer<Void> clientData) {
  try {
    if (cursor.kind() == clang.CXCursorKind.CXCursor_FieldDecl) {
      _logger.finer('===== member: ${cursor.completeStringRepr()}');

      final mt = cursor.type().toCodeGenTypeAndDispose();

      //TODO(4): Remove these when support for Structs by value arrives.
      if (mt.broadType == BroadType.Struct) {
        // Setting this flag will exclude adding members for this struct's bindings.
        nestedStructMember = true;
      } else if (mt.broadType == BroadType.ConstantArray) {
        if (mt.elementType.broadType == BroadType.Struct) {
          // Setting this flag will exclude adding members for this struct's bindings.
          nestedStructMember = true;
        }
      }

      if (mt.getBaseBroadType() == BroadType.Unimplemented) {
        unimplementedMemberType = true;
      }

      _members.add(
        Member(
          name: cursor.spelling(),
          type: mt,
        ),
      );
    }
    cursor.dispose();
    parent.dispose();
  } catch (e, s) {
    _logger.severe(e);
    _logger.severe(s);
    rethrow;
  }
  return clang.CXChildVisitResult.CXChildVisit_Continue;
}