Squashed 'third_party/flatbuffers/' content from commit acc9990ab

Change-Id: I48550d40d78fea996ebe74e9723a5d1f910de491
git-subtree-dir: third_party/flatbuffers
git-subtree-split: acc9990abd2206491480291b0f85f925110102ea
diff --git a/src/idl_gen_dart.cpp b/src/idl_gen_dart.cpp
new file mode 100644
index 0000000..2346a85
--- /dev/null
+++ b/src/idl_gen_dart.cpp
@@ -0,0 +1,914 @@
+/*
+ * Copyright 2018 Dan Field
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// independent from idl_parser, since this code is not needed for most clients
+#include <cassert>
+
+#include "flatbuffers/code_generators.h"
+#include "flatbuffers/flatbuffers.h"
+#include "flatbuffers/idl.h"
+#include "flatbuffers/util.h"
+
+namespace flatbuffers {
+
+static std::string GeneratedFileName(const std::string &path,
+                                     const std::string &file_name) {
+  return path + file_name + "_generated.dart";
+}
+
+namespace dart {
+
+const std::string _kFb = "fb";
+// see https://www.dartlang.org/guides/language/language-tour#keywords
+// yeild*, async*, and sync* shouldn't be problems anyway but keeping them in
+static const char *keywords[] = {
+  "abstract",   "deferred", "if",       "super",   "as",       "do",
+  "implements", "switch",   "assert",   "dynamic", "import",   "sync*",
+  "async",      "else",     "in",       "this",    "async*",   "enum",
+  "is",         "throw",    "await",    "export",  "library",  "true",
+  "break",      "external", "new",      "try",     "case",     "extends",
+  "null",       "typedef",  "catch",    "factory", "operator", "var",
+  "class",      "false",    "part",     "void",    "const",    "final",
+  "rethrow",    "while",    "continue", "finally", "return",   "with",
+  "covariant",  "for",      "set",      "yield",   "default",  "get",
+  "static",     "yield*"
+};
+
+// Iterate through all definitions we haven't generate code for (enums, structs,
+// and tables) and output them to a single file.
+class DartGenerator : public BaseGenerator {
+ public:
+  typedef std::map<std::string, std::string> namespace_code_map;
+
+  DartGenerator(const Parser &parser, const std::string &path,
+                const std::string &file_name)
+      : BaseGenerator(parser, path, file_name, "", ".") {}
+  // Iterate through all definitions we haven't generate code for (enums,
+  // structs, and tables) and output them to a single file.
+  bool generate() {
+    std::string code;
+    namespace_code_map namespace_code;
+    GenerateEnums(&namespace_code);
+    GenerateStructs(&namespace_code);
+
+    for (auto kv = namespace_code.begin(); kv != namespace_code.end(); ++kv) {
+      code.clear();
+      code = code + "// " + FlatBuffersGeneratedWarning() + "\n";
+      code = code +
+             "// ignore_for_file: unused_import, unused_field, "
+             "unused_local_variable\n\n";
+
+      code += "library " + kv->first + ";\n\n";
+
+      code += "import 'dart:typed_data' show Uint8List;\n";
+      code += "import 'package:flat_buffers/flat_buffers.dart' as " + _kFb +
+              ";\n\n";
+
+      if (parser_.opts.include_dependence_headers) {
+        GenIncludeDependencies(&code, kv->first);
+      }
+
+      for (auto kv2 = namespace_code.begin(); kv2 != namespace_code.end();
+           ++kv2) {
+        if (kv2->first != kv->first) {
+          code += "import '" +
+                  GeneratedFileName("./", file_name_ + "_" + kv2->first) +
+                  "' as " + ImportAliasName(kv2->first) + ";\n";
+        }
+      }
+      code += "\n";
+      code += kv->second;
+
+      if (!SaveFile(
+              GeneratedFileName(path_, file_name_ + "_" + kv->first).c_str(),
+              code, false)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+ private:
+  static std::string ImportAliasName(const std::string &ns) {
+    std::string ret;
+    ret.assign(ns);
+    size_t pos = ret.find('.');
+    while (pos != std::string::npos) {
+      ret.replace(pos, 1, "_");
+      pos = ret.find('.', pos + 1);
+    }
+
+    return ret;
+  }
+
+  static std::string BuildNamespaceName(const Namespace &ns) {
+    std::stringstream sstream;
+    std::copy(ns.components.begin(), ns.components.end() - 1,
+              std::ostream_iterator<std::string>(sstream, "."));
+
+    auto ret = sstream.str() + ns.components.back();
+    for (size_t i = 0; i < ret.size(); i++) {
+      auto lower = tolower(ret[i]);
+      if (lower != ret[i]) {
+        ret[i] = static_cast<char>(lower);
+        if (i != 0 && ret[i - 1] != '.') {
+          ret.insert(i, "_");
+          i++;
+        }
+      }
+    }
+    // std::transform(ret.begin(), ret.end(), ret.begin(), ::tolower);
+    return ret;
+  }
+
+  void GenIncludeDependencies(std::string* code, const std::string& the_namespace) {
+    for (auto it = parser_.included_files_.begin();
+         it != parser_.included_files_.end(); ++it) {
+      if (it->second.empty()) continue;
+
+      auto noext = flatbuffers::StripExtension(it->second);
+      auto basename = flatbuffers::StripPath(noext);
+
+      *code += "import '" + GeneratedFileName("", basename + "_" + the_namespace) + "';\n";
+    }
+  }
+
+  static std::string EscapeKeyword(const std::string &name) {
+    for (size_t i = 0; i < sizeof(keywords) / sizeof(keywords[0]); i++) {
+      if (name == keywords[i]) { return MakeCamel(name + "_", false); }
+    }
+
+    return MakeCamel(name, false);
+  }
+
+  void GenerateEnums(namespace_code_map *namespace_code) {
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+         ++it) {
+      auto &enum_def = **it;
+      GenEnum(enum_def, namespace_code);  // enum_code_ptr);
+    }
+  }
+
+  void GenerateStructs(namespace_code_map *namespace_code) {
+    for (auto it = parser_.structs_.vec.begin();
+         it != parser_.structs_.vec.end(); ++it) {
+      auto &struct_def = **it;
+      GenStruct(struct_def, namespace_code);
+    }
+  }
+
+  // Generate a documentation comment, if available.
+  static void GenDocComment(const std::vector<std::string> &dc,
+                            std::string *code_ptr,
+                            const std::string &extra_lines,
+                            const char *indent = nullptr) {
+    if (dc.empty() && extra_lines.empty()) {
+      // Don't output empty comment blocks with 0 lines of comment content.
+      return;
+    }
+
+    auto &code = *code_ptr;
+
+    for (auto it = dc.begin(); it != dc.end(); ++it) {
+      if (indent) code += indent;
+      code += "/// " + *it + "\n";
+    }
+    if (!extra_lines.empty()) {
+      if (!dc.empty()) {
+        if (indent) code += indent;
+        code += "///\n";
+      }
+      if (indent) code += indent;
+      std::string::size_type start = 0;
+      for (;;) {
+        auto end = extra_lines.find('\n', start);
+        if (end != std::string::npos) {
+          code += "/// " + extra_lines.substr(start, end - start) + "\n";
+          start = end + 1;
+        } else {
+          code += "/// " + extra_lines.substr(start) + "\n";
+          break;
+        }
+      }
+    }
+  }
+
+  static void GenDocComment(std::string *code_ptr,
+                            const std::string &extra_lines) {
+    GenDocComment(std::vector<std::string>(), code_ptr, extra_lines);
+  }
+
+  // Generate an enum declaration and an enum string lookup table.
+  void GenEnum(EnumDef &enum_def, namespace_code_map *namespace_code) {
+    if (enum_def.generated) return;
+    auto ns = BuildNamespaceName(*enum_def.defined_namespace);
+    std::string code;
+    GenDocComment(enum_def.doc_comment, &code, "");
+
+    auto name = enum_def.is_union ? enum_def.name + "TypeId" : enum_def.name;
+    auto is_bit_flags = enum_def.attributes.Lookup("bit_flags");
+
+    code += "class " + name + " {\n";
+    code += "  final int value;\n";
+    code += "  const " + name + "._(this.value);\n\n";
+    code += "  factory " + name + ".fromValue(int value) {\n";
+    code += "    if (value == null) value = 0;\n";
+
+    code += "    if (!values.containsKey(value)) {\n";
+    code +=
+        "      throw new StateError('Invalid value $value for bit flag enum ";
+    code += name + "');\n";
+    code += "    }\n";
+
+    code += "    return values[value];\n";
+    code += "  }\n\n";
+
+    // this is meaningless for bit_flags
+    // however, note that unlike "regular" dart enums this enum can still have
+    // holes.
+    if (!is_bit_flags) {
+      code += "  static const int minValue = " +
+              enum_def.ToString(*enum_def.MinValue()) + ";\n";
+      code += "  static const int maxValue = " +
+              enum_def.ToString(*enum_def.MaxValue()) + ";\n";
+    }
+
+    code +=
+        "  static bool containsValue(int value) =>"
+        " values.containsKey(value);\n\n";
+
+    for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
+      auto &ev = **it;
+
+      if (!ev.doc_comment.empty()) {
+        if (it != enum_def.Vals().begin()) { code += '\n'; }
+        GenDocComment(ev.doc_comment, &code, "", "  ");
+      }
+      code += "  static const " + name + " " + ev.name + " = ";
+      code += "const " + name + "._(" + enum_def.ToString(ev) + ");\n";
+    }
+
+    code += "  static get values => {";
+    for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
+      auto &ev = **it;
+      code += enum_def.ToString(ev) + ": " + ev.name + ",";
+    }
+    code += "};\n\n";
+
+    code += "  static const " + _kFb + ".Reader<" + name +
+            "> reader = const _" + name + "Reader();\n\n";
+    code += "  @override\n";
+    code += "  String toString() {\n";
+    code += "    return '" + name + "{value: $value}';\n";
+    code += "  }\n";
+    code += "}\n\n";
+
+    GenEnumReader(enum_def, name, &code);
+    (*namespace_code)[ns] += code;
+  }
+
+  void GenEnumReader(EnumDef &enum_def, const std::string &name,
+                     std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    code += "class _" + name + "Reader extends " + _kFb + ".Reader<" + name +
+            "> {\n";
+    code += "  const _" + name + "Reader();\n\n";
+    code += "  @override\n";
+    code += "  int get size => 1;\n\n";
+    code += "  @override\n";
+    code +=
+        "  " + name + " read(" + _kFb + ".BufferContext bc, int offset) =>\n";
+    code += "      new " + name + ".fromValue(const " + _kFb + "." +
+            GenType(enum_def.underlying_type) + "Reader().read(bc, offset));\n";
+    code += "}\n\n";
+  }
+
+  static std::string GenType(const Type &type) {
+    switch (type.base_type) {
+      case BASE_TYPE_BOOL: return "Bool";
+      case BASE_TYPE_CHAR: return "Int8";
+      case BASE_TYPE_UTYPE:
+      case BASE_TYPE_UCHAR: return "Uint8";
+      case BASE_TYPE_SHORT: return "Int16";
+      case BASE_TYPE_USHORT: return "Uint16";
+      case BASE_TYPE_INT: return "Int32";
+      case BASE_TYPE_UINT: return "Uint32";
+      case BASE_TYPE_LONG: return "Int64";
+      case BASE_TYPE_ULONG: return "Uint64";
+      case BASE_TYPE_FLOAT: return "Float32";
+      case BASE_TYPE_DOUBLE: return "Float64";
+      case BASE_TYPE_STRING: return "String";
+      case BASE_TYPE_VECTOR: return GenType(type.VectorType());
+      case BASE_TYPE_STRUCT: return type.struct_def->name;
+      case BASE_TYPE_UNION: return type.enum_def->name + "TypeId";
+      default: return "Table";
+    }
+  }
+
+  std::string GenReaderTypeName(const Type &type, Namespace *current_namespace,
+                                const FieldDef &def,
+                                bool parent_is_vector = false) {
+    if (type.base_type == BASE_TYPE_BOOL) {
+      return "const " + _kFb + ".BoolReader()";
+    } else if (type.base_type == BASE_TYPE_VECTOR) {
+      return "const " + _kFb + ".ListReader<" +
+             GenDartTypeName(type.VectorType(), current_namespace, def) + ">(" +
+             GenReaderTypeName(type.VectorType(), current_namespace, def,
+                               true) +
+             ")";
+    } else if (type.base_type == BASE_TYPE_STRING) {
+      return "const " + _kFb + ".StringReader()";
+    }
+    if (IsScalar(type.base_type)) {
+      if (type.enum_def && parent_is_vector) {
+        return GenDartTypeName(type, current_namespace, def) + ".reader";
+      }
+      return "const " + _kFb + "." + GenType(type) + "Reader()";
+    } else {
+      return GenDartTypeName(type, current_namespace, def) + ".reader";
+    }
+  }
+
+  std::string GenDartTypeName(const Type &type, Namespace *current_namespace,
+                              const FieldDef &def, bool addBuilder = false) {
+    if (type.enum_def) {
+      if (type.enum_def->is_union && type.base_type != BASE_TYPE_UNION) {
+        return type.enum_def->name + "TypeId";
+      } else if (type.enum_def->is_union) {
+        return "dynamic";
+      } else if (type.base_type != BASE_TYPE_VECTOR) {
+        return type.enum_def->name;
+      }
+    }
+
+    switch (type.base_type) {
+      case BASE_TYPE_BOOL: return "bool";
+      case BASE_TYPE_LONG:
+      case BASE_TYPE_ULONG:
+      case BASE_TYPE_INT:
+      case BASE_TYPE_UINT:
+      case BASE_TYPE_SHORT:
+      case BASE_TYPE_USHORT:
+      case BASE_TYPE_CHAR:
+      case BASE_TYPE_UCHAR: return "int";
+      case BASE_TYPE_FLOAT:
+      case BASE_TYPE_DOUBLE: return "double";
+      case BASE_TYPE_STRING: return "String";
+      case BASE_TYPE_STRUCT:
+        return MaybeWrapNamespace(
+            type.struct_def->name + (addBuilder ? "ObjectBuilder" : ""),
+            current_namespace, def);
+      case BASE_TYPE_VECTOR:
+        return "List<" +
+               GenDartTypeName(type.VectorType(), current_namespace, def,
+                               addBuilder) +
+               ">";
+      default: assert(0); return "dynamic";
+    }
+  }
+
+  static const std::string MaybeWrapNamespace(const std::string &type_name,
+                                              Namespace *current_ns,
+                                              const FieldDef &field) {
+    auto curr_ns_str = BuildNamespaceName(*current_ns);
+    std::string field_ns_str = "";
+    if (field.value.type.struct_def) {
+      field_ns_str +=
+          BuildNamespaceName(*field.value.type.struct_def->defined_namespace);
+    } else if (field.value.type.enum_def) {
+      field_ns_str +=
+          BuildNamespaceName(*field.value.type.enum_def->defined_namespace);
+    }
+
+    if (field_ns_str != "" && field_ns_str != curr_ns_str) {
+      return ImportAliasName(field_ns_str) + "." + type_name;
+    } else {
+      return type_name;
+    }
+  }
+
+  // Generate an accessor struct with constructor for a flatbuffers struct.
+  void GenStruct(const StructDef &struct_def,
+                 namespace_code_map *namespace_code) {
+    if (struct_def.generated) return;
+
+    auto object_namespace = BuildNamespaceName(*struct_def.defined_namespace);
+    std::string code;
+
+    const auto &object_name = struct_def.name;
+
+    // Emit constructor
+
+    GenDocComment(struct_def.doc_comment, &code, "");
+
+    auto reader_name = "_" + object_name + "Reader";
+    auto builder_name = object_name + "Builder";
+    auto object_builder_name = object_name + "ObjectBuilder";
+
+    std::string reader_code, builder_code;
+
+    code += "class " + object_name + " {\n";
+
+    code += "  " + object_name + "._(this._bc, this._bcOffset);\n";
+    if (!struct_def.fixed) {
+      code += "  factory " + object_name + "(List<int> bytes) {\n";
+      code += "    " + _kFb + ".BufferContext rootRef = new " + _kFb +
+              ".BufferContext.fromBytes(bytes);\n";
+      code += "    return reader.read(rootRef, 0);\n";
+      code += "  }\n";
+    }
+
+    code += "\n";
+    code += "  static const " + _kFb + ".Reader<" + object_name +
+            "> reader = const " + reader_name + "();\n\n";
+
+    code += "  final " + _kFb + ".BufferContext _bc;\n";
+    code += "  final int _bcOffset;\n\n";
+
+    GenImplementationGetters(struct_def, &code);
+
+    code += "}\n\n";
+
+    GenReader(struct_def, &reader_name, &reader_code);
+    GenBuilder(struct_def, &builder_name, &builder_code);
+    GenObjectBuilder(struct_def, &object_builder_name, &builder_code);
+
+    code += reader_code;
+    code += builder_code;
+
+    (*namespace_code)[object_namespace] += code;
+  }
+
+  std::string NamespaceAliasFromUnionType(const std::string &in) {
+    if (in.find('_') == std::string::npos) { return in; }
+
+    std::stringstream ss(in);
+    std::string item;
+    std::vector<std::string> parts;
+    std::string ns;
+
+    while (std::getline(ss, item, '_')) { parts.push_back(item); }
+
+    for (auto it = parts.begin(); it != parts.end() - 1; ++it) {
+      auto &part = *it;
+
+      for (size_t i = 0; i < part.length(); i++) {
+        if (i && !isdigit(part[i]) &&
+            part[i] == static_cast<char>(toupper(part[i]))) {
+          ns += "_";
+          ns += static_cast<char>(tolower(part[i]));
+        } else {
+          ns += static_cast<char>(tolower(part[i]));
+        }
+      }
+      if (it != parts.end() - 2) { ns += "_"; }
+    }
+
+    return ns + "." + parts.back();
+  }
+
+  void GenImplementationGetters(const StructDef &struct_def,
+                                std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      std::string field_name = MakeCamel(field.name, false);
+      std::string type_name = GenDartTypeName(
+          field.value.type, struct_def.defined_namespace, field, false);
+
+      GenDocComment(field.doc_comment, &code, "", "  ");
+
+      code += "  " + type_name + " get " + field_name;
+      if (field.value.type.base_type == BASE_TYPE_UNION) {
+        code += " {\n";
+        code += "    switch (" + field_name + "Type?.value) {\n";
+        auto &enum_def = *field.value.type.enum_def;
+        for (auto en_it = enum_def.Vals().begin() + 1;
+             en_it != enum_def.Vals().end(); ++en_it) {
+          auto &ev = **en_it;
+
+          auto enum_name = NamespaceAliasFromUnionType(ev.name);
+          code += "      case " + enum_def.ToString(ev) + ": return " +
+                  enum_name + ".reader.vTableGet(_bc, _bcOffset, " +
+                  NumToString(field.value.offset) + ", null);\n";
+        }
+        code += "      default: return null;\n";
+        code += "    }\n";
+        code += "  }\n";
+      } else {
+        code += " => ";
+        if (field.value.type.enum_def &&
+            field.value.type.base_type != BASE_TYPE_VECTOR) {
+          code += "new " +
+                  GenDartTypeName(field.value.type,
+                                  struct_def.defined_namespace, field) +
+                  ".fromValue(";
+        }
+
+        code += GenReaderTypeName(field.value.type,
+                                  struct_def.defined_namespace, field);
+        if (struct_def.fixed) {
+          code +=
+              ".read(_bc, _bcOffset + " + NumToString(field.value.offset) + ")";
+        } else {
+          code += ".vTableGet(_bc, _bcOffset, " +
+                  NumToString(field.value.offset) + ", ";
+          if (!field.value.constant.empty() && field.value.constant != "0") {
+            if (IsBool(field.value.type.base_type)) {
+              code += "true";
+            } else {
+              code += field.value.constant;
+            }
+          } else {
+            if (IsBool(field.value.type.base_type)) {
+              code += "false";
+            } else if (IsScalar(field.value.type.base_type)) {
+              code += "0";
+            } else {
+              code += "null";
+            }
+          }
+          code += ")";
+        }
+        if (field.value.type.enum_def &&
+            field.value.type.base_type != BASE_TYPE_VECTOR) {
+          code += ")";
+        }
+        code += ";\n";
+      }
+    }
+
+    code += "\n";
+
+    code += "  @override\n";
+    code += "  String toString() {\n";
+    code += "    return '" + struct_def.name + "{";
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+      code +=
+          MakeCamel(field.name, false) + ": $" + MakeCamel(field.name, false);
+      if (it != struct_def.fields.vec.end() - 1) { code += ", "; }
+    }
+    code += "}';\n";
+    code += "  }\n";
+  }
+
+  void GenReader(const StructDef &struct_def, std::string *reader_name_ptr,
+                 std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto &reader_name = *reader_name_ptr;
+    auto &impl_name = struct_def.name;
+
+    code += "class " + reader_name + " extends " + _kFb;
+    if (struct_def.fixed) {
+      code += ".StructReader<";
+    } else {
+      code += ".TableReader<";
+    }
+    code += impl_name + "> {\n";
+    code += "  const " + reader_name + "();\n\n";
+
+    if (struct_def.fixed) {
+      code += "  @override\n";
+      code += "  int get size => " + NumToString(struct_def.bytesize) + ";\n\n";
+    }
+    code += "  @override\n";
+    code += "  " + impl_name +
+            " createObject(fb.BufferContext bc, int offset) => \n    new " +
+            impl_name + "._(bc, offset);\n";
+    code += "}\n\n";
+  }
+
+  void GenBuilder(const StructDef &struct_def, std::string *builder_name_ptr,
+                  std::string *code_ptr) {
+    if (struct_def.fields.vec.size() == 0) { return; }
+    auto &code = *code_ptr;
+    auto &builder_name = *builder_name_ptr;
+
+    code += "class " + builder_name + " {\n";
+    code += "  " + builder_name + "(this.fbBuilder) {\n";
+    code += "    assert(fbBuilder != null);\n";
+    code += "  }\n\n";
+    code += "  final " + _kFb + ".Builder fbBuilder;\n\n";
+
+    if (struct_def.fixed) {
+      StructBuilderBody(struct_def, code_ptr);
+    } else {
+      TableBuilderBody(struct_def, code_ptr);
+    }
+
+    code += "}\n\n";
+  }
+
+  void StructBuilderBody(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    code += "  int finish(";
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      if (IsStruct(field.value.type)) {
+        code += "fb.StructBuilder";
+      } else {
+        code += GenDartTypeName(field.value.type, struct_def.defined_namespace,
+                                field);
+      }
+      code += " " + field.name;
+      if (it != struct_def.fields.vec.end() - 1) { code += ", "; }
+    }
+    code += ") {\n";
+
+    for (auto it = struct_def.fields.vec.rbegin();
+         it != struct_def.fields.vec.rend(); ++it) {
+      auto &field = **it;
+
+      if (field.deprecated) continue;
+
+      if (field.padding) {
+        code += "    fbBuilder.pad(" + NumToString(field.padding) + ");\n";
+      }
+
+      if (IsStruct(field.value.type)) {
+        code += "    " + field.name + "();\n";
+      } else {
+        code += "    fbBuilder.put" + GenType(field.value.type) + "(";
+        code += field.name;
+        if (field.value.type.enum_def) { code += "?.value"; }
+        code += ");\n";
+      }
+    }
+    code += "    return fbBuilder.offset;\n";
+    code += "  }\n\n";
+  }
+
+  void TableBuilderBody(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    code += "  void begin() {\n";
+    code += "    fbBuilder.startTable();\n";
+    code += "  }\n\n";
+
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      auto offset = it - struct_def.fields.vec.begin();
+
+      if (IsScalar(field.value.type.base_type)) {
+        code += "  int add" + MakeCamel(field.name) + "(";
+        code += GenDartTypeName(field.value.type, struct_def.defined_namespace,
+                                field);
+        code += " " + MakeCamel(field.name, false) + ") {\n";
+        code += "    fbBuilder.add" + GenType(field.value.type) + "(" +
+                NumToString(offset) + ", ";
+        code += MakeCamel(field.name, false);
+        if (field.value.type.enum_def) { code += "?.value"; }
+        code += ");\n";
+      } else if (IsStruct(field.value.type)) {
+        code += "  int add" + MakeCamel(field.name) + "(int offset) {\n";
+        code +=
+            "    fbBuilder.addStruct(" + NumToString(offset) + ", offset);\n";
+      } else {
+        code += "  int add" + MakeCamel(field.name) + "Offset(int offset) {\n";
+        code +=
+            "    fbBuilder.addOffset(" + NumToString(offset) + ", offset);\n";
+      }
+      code += "    return fbBuilder.offset;\n";
+      code += "  }\n";
+    }
+
+    code += "\n";
+    code += "  int finish() {\n";
+    code += "    return fbBuilder.endTable();\n";
+    code += "  }\n";
+  }
+
+  void GenObjectBuilder(const StructDef &struct_def,
+                        std::string *builder_name_ptr, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto &builder_name = *builder_name_ptr;
+
+    code += "class " + builder_name + " extends " + _kFb + ".ObjectBuilder {\n";
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+      code += "  final " +
+              GenDartTypeName(field.value.type, struct_def.defined_namespace,
+                              field, true) +
+              " _" + MakeCamel(field.name, false) + ";\n";
+    }
+    code += "\n";
+    code += "  " + builder_name + "(";
+    if (struct_def.fields.vec.size() != 0) {
+      code +=
+
+          "{\n";
+      for (auto it = struct_def.fields.vec.begin();
+           it != struct_def.fields.vec.end(); ++it) {
+        auto &field = **it;
+        if (field.deprecated) continue;
+        code += "    " +
+                GenDartTypeName(field.value.type, struct_def.defined_namespace,
+                                field, true) +
+                " " + MakeCamel(field.name, false) + ",\n";
+      }
+      code += "  })\n";
+      code += "      : ";
+      for (auto it = struct_def.fields.vec.begin();
+           it != struct_def.fields.vec.end(); ++it) {
+        auto &field = **it;
+        if (field.deprecated) continue;
+        code += "_" + MakeCamel(field.name, false) + " = " +
+                MakeCamel(field.name, false);
+        if (it == struct_def.fields.vec.end() - 1) {
+          code += ";\n\n";
+        } else {
+          code += ",\n        ";
+        }
+      }
+    } else {
+      code += ");\n\n";
+    }
+
+    code += "  /// Finish building, and store into the [fbBuilder].\n";
+    code += "  @override\n";
+    code += "  int finish(\n";
+    code += "    " + _kFb + ".Builder fbBuilder) {\n";
+    code += "    assert(fbBuilder != null);\n";
+
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+      if (IsScalar(field.value.type.base_type) || IsStruct(field.value.type))
+        continue;
+
+      code += "    final int " + MakeCamel(field.name, false) + "Offset";
+      if (field.value.type.base_type == BASE_TYPE_VECTOR) {
+        code +=
+            " = _" + MakeCamel(field.name, false) + "?.isNotEmpty == true\n";
+        code += "        ? fbBuilder.writeList";
+        switch (field.value.type.VectorType().base_type) {
+          case BASE_TYPE_STRING:
+            code += "(_" + MakeCamel(field.name, false) +
+                    ".map((b) => fbBuilder.writeString(b)).toList())";
+            break;
+          case BASE_TYPE_STRUCT:
+            if (field.value.type.struct_def->fixed) {
+              code += "OfStructs(_" + MakeCamel(field.name, false) + ")";
+            } else {
+              code += "(_" + MakeCamel(field.name, false) +
+                      ".map((b) => b.getOrCreateOffset(fbBuilder)).toList())";
+            }
+            break;
+          default:
+            code += GenType(field.value.type.VectorType()) + "(_" +
+                    MakeCamel(field.name, false);
+            if (field.value.type.enum_def) { code += ".map((f) => f.value)"; }
+            code += ")";
+        }
+        code += "\n        : null;\n";
+      } else if (field.value.type.base_type == BASE_TYPE_STRING) {
+        code += " = fbBuilder.writeString(_" + MakeCamel(field.name, false) + ");\n";
+      } else {
+        code += " = _" + MakeCamel(field.name, false) +
+                "?.getOrCreateOffset(fbBuilder);\n";
+      }
+    }
+
+    code += "\n";
+    if (struct_def.fixed) {
+      StructObjectBuilderBody(struct_def, code_ptr);
+    } else {
+      TableObjectBuilderBody(struct_def, code_ptr);
+    }
+    code += "  }\n\n";
+
+    code += "  /// Convenience method to serialize to byte list.\n";
+    code += "  @override\n";
+    code += "  Uint8List toBytes([String fileIdentifier]) {\n";
+    code += "    " + _kFb + ".Builder fbBuilder = new ";
+    code += _kFb + ".Builder();\n";
+    code += "    int offset = finish(fbBuilder);\n";
+    code += "    return fbBuilder.finish(offset, fileIdentifier);\n";
+    code += "  }\n";
+    code += "}\n";
+  }
+
+  void StructObjectBuilderBody(const StructDef &struct_def,
+                               std::string *code_ptr,
+                               bool prependUnderscore = true) {
+    auto &code = *code_ptr;
+
+    for (auto it = struct_def.fields.vec.rbegin();
+         it != struct_def.fields.vec.rend(); ++it) {
+      auto &field = **it;
+
+      if (field.deprecated) continue;
+
+      if (field.padding) {
+        code += "    fbBuilder.pad(" + NumToString(field.padding) + ");\n";
+      }
+
+      if (IsStruct(field.value.type)) {
+        code += "    ";
+        if (prependUnderscore) { code += "_"; }
+        code += field.name + ".finish(fbBuilder);\n";
+      } else {
+        code += "    fbBuilder.put" + GenType(field.value.type) + "(";
+        if (prependUnderscore) { code += "_"; }
+        code += field.name;
+        if (field.value.type.enum_def) { code += "?.value"; }
+        code += ");\n";
+      }
+    }
+
+    code += "    return fbBuilder.offset;\n";
+  }
+
+  void TableObjectBuilderBody(const StructDef &struct_def,
+                              std::string *code_ptr,
+                              bool prependUnderscore = true) {
+    std::string &code = *code_ptr;
+    code += "    fbBuilder.startTable();\n";
+
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+
+      if (field.deprecated) continue;
+
+      auto offset = it - struct_def.fields.vec.begin();
+      if (IsScalar(field.value.type.base_type)) {
+        code += "    fbBuilder.add" + GenType(field.value.type) + "(" +
+                NumToString(offset) + ", ";
+        if (prependUnderscore) { code += "_"; }
+        code += MakeCamel(field.name, false);
+        if (field.value.type.enum_def) { code += "?.value"; }
+        code += ");\n";
+      } else if (IsStruct(field.value.type)) {
+        code += "    if (";
+        if (prependUnderscore) { code += "_"; }
+        code += MakeCamel(field.name, false) + " != null) {\n";
+        code += "      fbBuilder.addStruct(" + NumToString(offset) + ", ";
+        code += "_" + MakeCamel(field.name, false) + ".finish(fbBuilder));\n";
+        code += "    }\n";
+      } else {
+        code +=
+            "    if (" + MakeCamel(field.name, false) + "Offset != null) {\n";
+        code += "      fbBuilder.addOffset(" + NumToString(offset) + ", " +
+                MakeCamel(field.name, false) + "Offset);\n";
+        code += "    }\n";
+      }
+    }
+    code += "    return fbBuilder.endTable();\n";
+  }
+};
+}  // namespace dart
+
+bool GenerateDart(const Parser &parser, const std::string &path,
+                  const std::string &file_name) {
+  dart::DartGenerator generator(parser, path, file_name);
+  return generator.generate();
+}
+
+std::string DartMakeRule(const Parser &parser, const std::string &path,
+                         const std::string &file_name) {
+  assert(parser.opts.lang <= IDLOptions::kMAX);
+
+  auto filebase =
+      flatbuffers::StripPath(flatbuffers::StripExtension(file_name));
+  auto make_rule = GeneratedFileName(path, filebase) + ": ";
+
+  auto included_files = parser.GetIncludedFilesRecursive(file_name);
+  for (auto it = included_files.begin(); it != included_files.end(); ++it) {
+    make_rule += " " + *it;
+  }
+  return make_rule;
+}
+
+}  // namespace flatbuffers