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idl_gen_cpp.cpp
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idl_gen_cpp.cpp
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/*
* Copyright 2014 Google Inc. All rights reserved.
*
* 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 <limits>
#include <string>
#include <unordered_set>
#include "flatbuffers/base.h"
#include "flatbuffers/code_generators.h"
#include "flatbuffers/flatbuffers.h"
#include "flatbuffers/flatc.h"
#include "flatbuffers/idl.h"
#include "flatbuffers/util.h"
namespace flatbuffers {
// Make numerical literal with type-suffix.
// This function is only needed for C++! Other languages do not need it.
static inline std::string NumToStringCpp(std::string val, BaseType type) {
// Avoid issues with -2147483648, -9223372036854775808.
switch (type) {
case BASE_TYPE_INT:
return (val != "-2147483648") ? val : ("(-2147483647 - 1)");
case BASE_TYPE_ULONG: return (val == "0") ? val : (val + "ULL");
case BASE_TYPE_LONG:
if (val == "-9223372036854775808")
return "(-9223372036854775807LL - 1LL)";
else
return (val == "0") ? val : (val + "LL");
default: return val;
}
}
static std::string GenIncludeGuard(const std::string &file_name,
const Namespace &name_space,
const std::string &postfix = "") {
// Generate include guard.
std::string guard = file_name;
// Remove any non-alpha-numeric characters that may appear in a filename.
struct IsAlnum {
bool operator()(char c) const { return !is_alnum(c); }
};
guard.erase(std::remove_if(guard.begin(), guard.end(), IsAlnum()),
guard.end());
guard = "FLATBUFFERS_GENERATED_" + guard;
guard += "_";
// For further uniqueness, also add the namespace.
for (auto it = name_space.components.begin();
it != name_space.components.end(); ++it) {
guard += *it + "_";
}
// Anything extra to add to the guard?
if (!postfix.empty()) { guard += postfix + "_"; }
guard += "H_";
std::transform(guard.begin(), guard.end(), guard.begin(), CharToUpper);
return guard;
}
static bool IsVectorOfPointers(const FieldDef &field) {
const auto &type = field.value.type;
const auto &vector_type = type.VectorType();
return type.base_type == BASE_TYPE_VECTOR &&
vector_type.base_type == BASE_TYPE_STRUCT &&
!vector_type.struct_def->fixed && !field.native_inline;
}
static bool IsPointer(const FieldDef &field) {
return field.value.type.base_type == BASE_TYPE_STRUCT &&
!IsStruct(field.value.type);
}
namespace cpp {
enum CppStandard { CPP_STD_X0 = 0, CPP_STD_11, CPP_STD_17 };
// Define a style of 'struct' constructor if it has 'Array' fields.
enum GenArrayArgMode {
kArrayArgModeNone, // don't generate initialization args
kArrayArgModeSpanStatic, // generate flatbuffers::span<T,N>
};
// Extension of IDLOptions for cpp-generator.
struct IDLOptionsCpp : public IDLOptions {
// All fields start with 'g_' prefix to distinguish from the base IDLOptions.
CppStandard g_cpp_std; // Base version of C++ standard.
bool g_only_fixed_enums; // Generate underlaying type for all enums.
IDLOptionsCpp(const IDLOptions &opts)
: IDLOptions(opts), g_cpp_std(CPP_STD_11), g_only_fixed_enums(true) {}
};
class CppGenerator : public BaseGenerator {
public:
CppGenerator(const Parser &parser, const std::string &path,
const std::string &file_name, IDLOptionsCpp opts)
: BaseGenerator(parser, path, file_name, "", "::", "h"),
cur_name_space_(nullptr),
opts_(opts),
float_const_gen_("std::numeric_limits<double>::",
"std::numeric_limits<float>::", "quiet_NaN()",
"infinity()") {
static const char *const keywords[] = {
"alignas",
"alignof",
"and",
"and_eq",
"asm",
"atomic_cancel",
"atomic_commit",
"atomic_noexcept",
"auto",
"bitand",
"bitor",
"bool",
"break",
"case",
"catch",
"char",
"char16_t",
"char32_t",
"class",
"compl",
"concept",
"const",
"constexpr",
"const_cast",
"continue",
"co_await",
"co_return",
"co_yield",
"decltype",
"default",
"delete",
"do",
"double",
"dynamic_cast",
"else",
"enum",
"explicit",
"export",
"extern",
"false",
"float",
"for",
"friend",
"goto",
"if",
"import",
"inline",
"int",
"long",
"module",
"mutable",
"namespace",
"new",
"noexcept",
"not",
"not_eq",
"nullptr",
"operator",
"or",
"or_eq",
"private",
"protected",
"public",
"register",
"reinterpret_cast",
"requires",
"return",
"short",
"signed",
"sizeof",
"static",
"static_assert",
"static_cast",
"struct",
"switch",
"synchronized",
"template",
"this",
"thread_local",
"throw",
"true",
"try",
"typedef",
"typeid",
"typename",
"union",
"unsigned",
"using",
"virtual",
"void",
"volatile",
"wchar_t",
"while",
"xor",
"xor_eq",
nullptr,
};
for (auto kw = keywords; *kw; kw++) keywords_.insert(*kw);
}
// Adds code to check that the included flatbuffers.h is of the same version
// as the generated code. This check currently looks for exact version match,
// as we would guarantee that they are compatible, but in theory a newer
// version of flatbuffers.h should work with a old code gen if we do proper
// backwards support.
void GenFlatbuffersVersionCheck() {
code_ +=
"// Ensure the included flatbuffers.h is the same version as when this "
"file was";
code_ += "// generated, otherwise it may not be compatible.";
code_ += "static_assert(FLATBUFFERS_VERSION_MAJOR == " +
std::to_string(FLATBUFFERS_VERSION_MAJOR) + " &&";
code_ += " FLATBUFFERS_VERSION_MINOR == " +
std::to_string(FLATBUFFERS_VERSION_MINOR) + " &&";
code_ += " FLATBUFFERS_VERSION_REVISION == " +
std::to_string(FLATBUFFERS_VERSION_REVISION) + ",";
code_ += " \"Non-compatible flatbuffers version included\");";
}
void GenIncludeDependencies() {
if (opts_.generate_object_based_api) {
for (auto it = parser_.native_included_files_.begin();
it != parser_.native_included_files_.end(); ++it) {
code_ += "#include \"" + *it + "\"";
}
}
// Get the directly included file of the file being parsed.
std::vector<IncludedFile> included_files(parser_.GetIncludedFiles());
// We are safe to sort them alphabetically, since there shouldn't be any
// interdependence between them.
std::stable_sort(included_files.begin(), included_files.end());
for (const IncludedFile &included_file : included_files) {
// Get the name of the included file as defined by the schema, and strip
// the .fbs extension.
const std::string name_without_ext =
flatbuffers::StripExtension(included_file.schema_name);
// If we are told to keep the prefix of the included schema, leave it
// unchanged, otherwise strip the leading path off so just the "basename"
// of the include is retained.
const std::string basename =
opts_.keep_prefix ? name_without_ext
: flatbuffers::StripPath(name_without_ext);
code_ += "#include \"" +
GeneratedFileName(opts_.include_prefix, basename, opts_) + "\"";
}
if (!parser_.native_included_files_.empty() || !included_files.empty()) {
code_ += "";
}
}
void GenExtraIncludes() {
for (std::size_t i = 0; i < opts_.cpp_includes.size(); ++i) {
code_ += "#include \"" + opts_.cpp_includes[i] + "\"";
}
if (!opts_.cpp_includes.empty()) { code_ += ""; }
}
std::string EscapeKeyword(const std::string &name) const {
return keywords_.find(name) == keywords_.end() ? name : name + "_";
}
std::string Name(const FieldDef &field) const {
// the union type field suffix is immutable.
static size_t union_suffix_len = strlen(UnionTypeFieldSuffix());
const bool is_union_type = field.value.type.base_type == BASE_TYPE_UTYPE;
// early return if no case transformation required
if (opts_.cpp_object_api_field_case_style ==
IDLOptions::CaseStyle_Unchanged)
return EscapeKeyword(field.name);
std::string name = field.name;
// do not change the case style of the union type field suffix
if (is_union_type) {
FLATBUFFERS_ASSERT(name.length() > union_suffix_len);
name.erase(name.length() - union_suffix_len, union_suffix_len);
}
if (opts_.cpp_object_api_field_case_style == IDLOptions::CaseStyle_Upper)
name = ConvertCase(name, Case::kUpperCamel);
else if (opts_.cpp_object_api_field_case_style ==
IDLOptions::CaseStyle_Lower)
name = ConvertCase(name, Case::kLowerCamel);
// restore the union field type suffix
if (is_union_type) name.append(UnionTypeFieldSuffix(), union_suffix_len);
return EscapeKeyword(name);
}
std::string Name(const Definition &def) const {
return EscapeKeyword(def.name);
}
std::string Name(const EnumVal &ev) const { return EscapeKeyword(ev.name); }
bool generate_bfbs_embed() {
code_.Clear();
code_ += "// " + std::string(FlatBuffersGeneratedWarning()) + "\n\n";
// If we don't have a root struct definition,
if (!parser_.root_struct_def_) {
// put a comment in the output why there is no code generated.
code_ += "// Binary schema not generated, no root struct found";
} else {
auto &struct_def = *parser_.root_struct_def_;
const auto include_guard =
GenIncludeGuard(file_name_, *struct_def.defined_namespace, "bfbs");
code_ += "#ifndef " + include_guard;
code_ += "#define " + include_guard;
code_ += "";
if (parser_.opts.gen_nullable) {
code_ += "#pragma clang system_header\n\n";
}
code_ += "#include \"flatbuffers/flatbuffers.h\"";
code_ += "";
GenFlatbuffersVersionCheck();
code_ += "";
SetNameSpace(struct_def.defined_namespace);
auto name = Name(struct_def);
code_.SetValue("STRUCT_NAME", name);
// Create code to return the binary schema data.
auto binary_schema_hex_text =
BufferToHexText(parser_.builder_.GetBufferPointer(),
parser_.builder_.GetSize(), 105, " ", "");
code_ += "struct {{STRUCT_NAME}}BinarySchema {";
code_ += " static const uint8_t *data() {";
code_ += " // Buffer containing the binary schema.";
code_ += " static const uint8_t bfbsData[" +
NumToString(parser_.builder_.GetSize()) + "] = {";
code_ += binary_schema_hex_text;
code_ += " };";
code_ += " return bfbsData;";
code_ += " }";
code_ += " static size_t size() {";
code_ += " return " + NumToString(parser_.builder_.GetSize()) + ";";
code_ += " }";
code_ += " const uint8_t *begin() {";
code_ += " return data();";
code_ += " }";
code_ += " const uint8_t *end() {";
code_ += " return data() + size();";
code_ += " }";
code_ += "};";
code_ += "";
if (cur_name_space_) SetNameSpace(nullptr);
// Close the include guard.
code_ += "#endif // " + include_guard;
}
// We are just adding "_bfbs" to the generated filename.
const auto file_path =
GeneratedFileName(path_, file_name_ + "_bfbs", opts_);
const auto final_code = code_.ToString();
return SaveFile(file_path.c_str(), final_code, false);
}
// Iterate through all definitions we haven't generate code for (enums,
// structs, and tables) and output them to a single file.
bool generate() {
code_.Clear();
code_ += "// " + std::string(FlatBuffersGeneratedWarning()) + "\n\n";
const auto include_guard =
GenIncludeGuard(file_name_, *parser_.current_namespace_);
code_ += "#ifndef " + include_guard;
code_ += "#define " + include_guard;
code_ += "";
if (opts_.gen_nullable) { code_ += "#pragma clang system_header\n\n"; }
code_ += "#include \"flatbuffers/flatbuffers.h\"";
if (parser_.uses_flexbuffers_) {
code_ += "#include \"flatbuffers/flexbuffers.h\"";
code_ += "#include \"flatbuffers/flex_flat_util.h\"";
}
code_ += "";
GenFlatbuffersVersionCheck();
code_ += "";
if (opts_.include_dependence_headers) { GenIncludeDependencies(); }
GenExtraIncludes();
FLATBUFFERS_ASSERT(!cur_name_space_);
// Generate forward declarations for all structs/tables, since they may
// have circular references.
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
const auto &struct_def = **it;
if (!struct_def.generated) {
SetNameSpace(struct_def.defined_namespace);
code_ += "struct " + Name(struct_def) + ";";
if (!struct_def.fixed) {
code_ += "struct " + Name(struct_def) + "Builder;";
}
if (opts_.generate_object_based_api) {
auto nativeName = NativeName(Name(struct_def), &struct_def, opts_);
if (!struct_def.fixed) { code_ += "struct " + nativeName + ";"; }
}
code_ += "";
}
}
// Generate forward declarations for all equal operators
if (opts_.generate_object_based_api && opts_.gen_compare) {
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
const auto &struct_def = **it;
if (!struct_def.generated) {
SetNameSpace(struct_def.defined_namespace);
auto nativeName = NativeName(Name(struct_def), &struct_def, opts_);
code_ += "bool operator==(const " + nativeName + " &lhs, const " +
nativeName + " &rhs);";
code_ += "bool operator!=(const " + nativeName + " &lhs, const " +
nativeName + " &rhs);";
}
}
code_ += "";
}
// Generate preablmle code for mini reflection.
if (opts_.mini_reflect != IDLOptions::kNone) {
// To break cyclic dependencies, first pre-declare all tables/structs.
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
const auto &struct_def = **it;
if (!struct_def.generated) {
SetNameSpace(struct_def.defined_namespace);
GenMiniReflectPre(&struct_def);
}
}
}
// Generate code for all the enum declarations.
for (const auto enum_def : parser_.enums_.vec) {
if (!enum_def->generated) {
SetNameSpace(enum_def->defined_namespace);
GenEnum(*enum_def);
}
}
// Generate code for all structs, then all tables.
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
const auto &struct_def = **it;
if (struct_def.fixed && !struct_def.generated) {
SetNameSpace(struct_def.defined_namespace);
GenStruct(struct_def);
}
}
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
const auto &struct_def = **it;
if (!struct_def.fixed && !struct_def.generated) {
SetNameSpace(struct_def.defined_namespace);
GenTable(struct_def);
}
}
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
const auto &struct_def = **it;
if (!struct_def.fixed && !struct_def.generated) {
SetNameSpace(struct_def.defined_namespace);
GenTablePost(struct_def);
}
}
// Generate code for union verifiers.
for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
++it) {
const auto &enum_def = **it;
if (enum_def.is_union && !enum_def.generated) {
SetNameSpace(enum_def.defined_namespace);
GenUnionPost(enum_def);
}
}
// Generate code for mini reflection.
if (opts_.mini_reflect != IDLOptions::kNone) {
// Then the unions/enums that may refer to them.
for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
++it) {
const auto &enum_def = **it;
if (!enum_def.generated) {
SetNameSpace(enum_def.defined_namespace);
GenMiniReflect(nullptr, &enum_def);
}
}
// Then the full tables/structs.
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
const auto &struct_def = **it;
if (!struct_def.generated) {
SetNameSpace(struct_def.defined_namespace);
GenMiniReflect(&struct_def, nullptr);
}
}
}
// Generate convenient global helper functions:
if (parser_.root_struct_def_) {
auto &struct_def = *parser_.root_struct_def_;
SetNameSpace(struct_def.defined_namespace);
auto name = Name(struct_def);
auto qualified_name = cur_name_space_->GetFullyQualifiedName(name);
auto cpp_name = TranslateNameSpace(qualified_name);
code_.SetValue("STRUCT_NAME", name);
code_.SetValue("CPP_NAME", cpp_name);
code_.SetValue("NULLABLE_EXT", NullableExtension());
// The root datatype accessor:
code_ += "inline \\";
code_ +=
"const {{CPP_NAME}} *{{NULLABLE_EXT}}Get{{STRUCT_NAME}}(const void "
"*buf) {";
code_ += " return flatbuffers::GetRoot<{{CPP_NAME}}>(buf);";
code_ += "}";
code_ += "";
code_ += "inline \\";
code_ +=
"const {{CPP_NAME}} "
"*{{NULLABLE_EXT}}GetSizePrefixed{{STRUCT_NAME}}(const void "
"*buf) {";
code_ += " return flatbuffers::GetSizePrefixedRoot<{{CPP_NAME}}>(buf);";
code_ += "}";
code_ += "";
if (opts_.mutable_buffer) {
code_ += "inline \\";
code_ += "{{STRUCT_NAME}} *GetMutable{{STRUCT_NAME}}(void *buf) {";
code_ += " return flatbuffers::GetMutableRoot<{{STRUCT_NAME}}>(buf);";
code_ += "}";
code_ += "";
code_ += "inline \\";
code_ +=
"{{CPP_NAME}} "
"*{{NULLABLE_EXT}}GetMutableSizePrefixed{{STRUCT_NAME}}(void "
"*buf) {";
code_ +=
" return "
"flatbuffers::GetMutableSizePrefixedRoot<{{CPP_NAME}}>(buf);";
code_ += "}";
code_ += "";
}
if (parser_.file_identifier_.length()) {
// Return the identifier
code_ += "inline const char *{{STRUCT_NAME}}Identifier() {";
code_ += " return \"" + parser_.file_identifier_ + "\";";
code_ += "}";
code_ += "";
// Check if a buffer has the identifier.
code_ += "inline \\";
code_ += "bool {{STRUCT_NAME}}BufferHasIdentifier(const void *buf) {";
code_ += " return flatbuffers::BufferHasIdentifier(";
code_ += " buf, {{STRUCT_NAME}}Identifier());";
code_ += "}";
code_ += "";
// Check if a size-prefixed buffer has the identifier.
code_ += "inline \\";
code_ +=
"bool SizePrefixed{{STRUCT_NAME}}BufferHasIdentifier(const void "
"*buf) {";
code_ += " return flatbuffers::BufferHasIdentifier(";
code_ += " buf, {{STRUCT_NAME}}Identifier(), true);";
code_ += "}";
code_ += "";
}
// The root verifier.
if (parser_.file_identifier_.length()) {
code_.SetValue("ID", name + "Identifier()");
} else {
code_.SetValue("ID", "nullptr");
}
code_ += "inline bool Verify{{STRUCT_NAME}}Buffer(";
code_ += " flatbuffers::Verifier &verifier) {";
code_ += " return verifier.VerifyBuffer<{{CPP_NAME}}>({{ID}});";
code_ += "}";
code_ += "";
code_ += "inline bool VerifySizePrefixed{{STRUCT_NAME}}Buffer(";
code_ += " flatbuffers::Verifier &verifier) {";
code_ +=
" return verifier.VerifySizePrefixedBuffer<{{CPP_NAME}}>({{ID}});";
code_ += "}";
code_ += "";
if (parser_.file_extension_.length()) {
// Return the extension
code_ += "inline const char *{{STRUCT_NAME}}Extension() {";
code_ += " return \"" + parser_.file_extension_ + "\";";
code_ += "}";
code_ += "";
}
// Finish a buffer with a given root object:
code_ += "inline void Finish{{STRUCT_NAME}}Buffer(";
code_ += " flatbuffers::FlatBufferBuilder &fbb,";
code_ += " flatbuffers::Offset<{{CPP_NAME}}> root) {";
if (parser_.file_identifier_.length())
code_ += " fbb.Finish(root, {{STRUCT_NAME}}Identifier());";
else
code_ += " fbb.Finish(root);";
code_ += "}";
code_ += "";
code_ += "inline void FinishSizePrefixed{{STRUCT_NAME}}Buffer(";
code_ += " flatbuffers::FlatBufferBuilder &fbb,";
code_ += " flatbuffers::Offset<{{CPP_NAME}}> root) {";
if (parser_.file_identifier_.length())
code_ += " fbb.FinishSizePrefixed(root, {{STRUCT_NAME}}Identifier());";
else
code_ += " fbb.FinishSizePrefixed(root);";
code_ += "}";
code_ += "";
if (opts_.generate_object_based_api) {
// A convenient root unpack function.
auto native_name = WrapNativeNameInNameSpace(struct_def, opts_);
code_.SetValue("UNPACK_RETURN",
GenTypeNativePtr(native_name, nullptr, false));
code_.SetValue("UNPACK_TYPE",
GenTypeNativePtr(native_name, nullptr, true));
code_ += "inline {{UNPACK_RETURN}} UnPack{{STRUCT_NAME}}(";
code_ += " const void *buf,";
code_ += " const flatbuffers::resolver_function_t *res = nullptr) {";
code_ += " return {{UNPACK_TYPE}}\\";
code_ += "(Get{{STRUCT_NAME}}(buf)->UnPack(res));";
code_ += "}";
code_ += "";
code_ += "inline {{UNPACK_RETURN}} UnPackSizePrefixed{{STRUCT_NAME}}(";
code_ += " const void *buf,";
code_ += " const flatbuffers::resolver_function_t *res = nullptr) {";
code_ += " return {{UNPACK_TYPE}}\\";
code_ += "(GetSizePrefixed{{STRUCT_NAME}}(buf)->UnPack(res));";
code_ += "}";
code_ += "";
}
}
if (cur_name_space_) SetNameSpace(nullptr);
// Close the include guard.
code_ += "#endif // " + include_guard;
const auto file_path = GeneratedFileName(path_, file_name_, opts_);
const auto final_code = code_.ToString();
// Save the file and optionally generate the binary schema code.
return SaveFile(file_path.c_str(), final_code, false) &&
(!parser_.opts.binary_schema_gen_embed || generate_bfbs_embed());
}
private:
CodeWriter code_;
std::unordered_set<std::string> keywords_;
// This tracks the current namespace so we can insert namespace declarations.
const Namespace *cur_name_space_;
const IDLOptionsCpp opts_;
const TypedFloatConstantGenerator float_const_gen_;
const Namespace *CurrentNameSpace() const { return cur_name_space_; }
// Translates a qualified name in flatbuffer text format to the same name in
// the equivalent C++ namespace.
static std::string TranslateNameSpace(const std::string &qualified_name) {
std::string cpp_qualified_name = qualified_name;
size_t start_pos = 0;
while ((start_pos = cpp_qualified_name.find('.', start_pos)) !=
std::string::npos) {
cpp_qualified_name.replace(start_pos, 1, "::");
}
return cpp_qualified_name;
}
bool TypeHasKey(const Type &type) {
if (type.base_type != BASE_TYPE_STRUCT) { return false; }
for (auto it = type.struct_def->fields.vec.begin();
it != type.struct_def->fields.vec.end(); ++it) {
const auto &field = **it;
if (field.key) { return true; }
}
return false;
}
bool VectorElementUserFacing(const Type &type) const {
return (opts_.scoped_enums && IsEnum(type)) ||
(opts_.g_cpp_std >= cpp::CPP_STD_17 && opts_.g_only_fixed_enums &&
IsEnum(type));
}
void GenComment(const std::vector<std::string> &dc, const char *prefix = "") {
std::string text;
::flatbuffers::GenComment(dc, &text, nullptr, prefix);
code_ += text + "\\";
}
// Return a C++ type from the table in idl.h
std::string GenTypeBasic(const Type &type, bool user_facing_type) const {
// clang-format off
static const char *const ctypename[] = {
#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
#CTYPE,
FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
#undef FLATBUFFERS_TD
};
// clang-format on
if (user_facing_type) {
if (type.enum_def) return WrapInNameSpace(*type.enum_def);
if (type.base_type == BASE_TYPE_BOOL) return "bool";
}
return ctypename[type.base_type];
}
// Return a C++ pointer type, specialized to the actual struct/table types,
// and vector element types.
std::string GenTypePointer(const Type &type) const {
switch (type.base_type) {
case BASE_TYPE_STRING: {
return "flatbuffers::String";
}
case BASE_TYPE_VECTOR: {
const auto type_name = GenTypeWire(
type.VectorType(), "", VectorElementUserFacing(type.VectorType()));
return "flatbuffers::Vector<" + type_name + ">";
}
case BASE_TYPE_STRUCT: {
return WrapInNameSpace(*type.struct_def);
}
case BASE_TYPE_UNION:
// fall through
default: {
return "void";
}
}
}
// Return a C++ type for any type (scalar/pointer) specifically for
// building a flatbuffer.
std::string GenTypeWire(const Type &type, const char *postfix,
bool user_facing_type) const {
if (IsScalar(type.base_type)) {
return GenTypeBasic(type, user_facing_type) + postfix;
} else if (IsStruct(type)) {
return "const " + GenTypePointer(type) + " *";
} else {
return "flatbuffers::Offset<" + GenTypePointer(type) + ">" + postfix;
}
}
// Return a C++ type for any type (scalar/pointer) that reflects its
// serialized size.
std::string GenTypeSize(const Type &type) const {
if (IsScalar(type.base_type)) {
return GenTypeBasic(type, false);
} else if (IsStruct(type)) {
return GenTypePointer(type);
} else {
return "flatbuffers::uoffset_t";
}
}
std::string NullableExtension() {
return opts_.gen_nullable ? " _Nullable " : "";
}
static std::string NativeName(const std::string &name, const StructDef *sd,
const IDLOptions &opts) {
return sd && !sd->fixed ? opts.object_prefix + name + opts.object_suffix
: name;
}
std::string WrapNativeNameInNameSpace(const StructDef &struct_def,
const IDLOptions &opts) {
return WrapInNameSpace(struct_def.defined_namespace,
NativeName(Name(struct_def), &struct_def, opts));
}
const std::string &PtrType(const FieldDef *field) {
auto attr = field ? field->attributes.Lookup("cpp_ptr_type") : nullptr;
return attr ? attr->constant : opts_.cpp_object_api_pointer_type;
}
const std::string NativeString(const FieldDef *field) {
auto attr = field ? field->attributes.Lookup("cpp_str_type") : nullptr;
auto &ret = attr ? attr->constant : opts_.cpp_object_api_string_type;
if (ret.empty()) { return "std::string"; }
return ret;
}
bool FlexibleStringConstructor(const FieldDef *field) {
auto attr = field
? (field->attributes.Lookup("cpp_str_flex_ctor") != nullptr)
: false;
auto ret = attr ? attr : opts_.cpp_object_api_string_flexible_constructor;
return ret && NativeString(field) !=
"std::string"; // Only for custom string types.
}
std::string GenTypeNativePtr(const std::string &type, const FieldDef *field,
bool is_constructor) {
auto &ptr_type = PtrType(field);
if (ptr_type != "naked") {
return (ptr_type != "default_ptr_type"
? ptr_type
: opts_.cpp_object_api_pointer_type) +
"<" + type + ">";
} else if (is_constructor) {
return "";
} else {
return type + " *";
}
}
std::string GenPtrGet(const FieldDef &field) {
auto cpp_ptr_type_get = field.attributes.Lookup("cpp_ptr_type_get");
if (cpp_ptr_type_get) return cpp_ptr_type_get->constant;
auto &ptr_type = PtrType(&field);
return ptr_type == "naked" ? "" : ".get()";
}
std::string GenOptionalNull() { return "flatbuffers::nullopt"; }
std::string GenOptionalDecl(const Type &type) {
return "flatbuffers::Optional<" + GenTypeBasic(type, true) + ">";
}
std::string GenTypeNative(const Type &type, bool invector,
const FieldDef &field, bool forcopy = false) {
switch (type.base_type) {
case BASE_TYPE_STRING: {
return NativeString(&field);
}
case BASE_TYPE_VECTOR: {
const auto type_name = GenTypeNative(type.VectorType(), true, field);
if (type.struct_def &&
type.struct_def->attributes.Lookup("native_custom_alloc")) {
auto native_custom_alloc =
type.struct_def->attributes.Lookup("native_custom_alloc");
return "std::vector<" + type_name + "," +
native_custom_alloc->constant + "<" + type_name + ">>";
} else
return "std::vector<" + type_name + ">";
}
case BASE_TYPE_STRUCT: {
auto type_name = WrapInNameSpace(*type.struct_def);
if (IsStruct(type)) {
auto native_type = type.struct_def->attributes.Lookup("native_type");
if (native_type) { type_name = native_type->constant; }
if (invector || field.native_inline || forcopy) {
return type_name;
} else {
return GenTypeNativePtr(type_name, &field, false);
}
} else {
const auto nn = WrapNativeNameInNameSpace(*type.struct_def, opts_);
return (forcopy || field.native_inline)
? nn
: GenTypeNativePtr(nn, &field, false);
}
}
case BASE_TYPE_UNION: {
auto type_name = WrapInNameSpace(*type.enum_def);
return type_name + "Union";
}
default: {
return field.IsScalarOptional() ? GenOptionalDecl(type)
: GenTypeBasic(type, true);
}
}
}
// Return a C++ type for any type (scalar/pointer) specifically for
// using a flatbuffer.
std::string GenTypeGet(const Type &type, const char *afterbasic,
const char *beforeptr, const char *afterptr,
bool user_facing_type) {
if (IsScalar(type.base_type)) {
return GenTypeBasic(type, user_facing_type) + afterbasic;
} else if (IsArray(type)) {
auto element_type = type.VectorType();
// Check if enum arrays are used in C++ without specifying --scoped-enums
if (IsEnum(element_type) && !opts_.g_only_fixed_enums) {
LogCompilerError(
"--scoped-enums must be enabled to use enum arrays in C++");
FLATBUFFERS_ASSERT(true);
}
return beforeptr +
(IsScalar(element_type.base_type)
? GenTypeBasic(element_type, user_facing_type)
: GenTypePointer(element_type)) +
afterptr;
} else {
return beforeptr + GenTypePointer(type) + afterptr;
}
}
std::string GenTypeSpan(const Type &type, bool immutable, size_t extent) {
// Generate "flatbuffers::span<const U, extent>".
FLATBUFFERS_ASSERT(IsSeries(type) && "unexpected type");
auto element_type = type.VectorType();
std::string text = "flatbuffers::span<";
text += immutable ? "const " : "";
if (IsScalar(element_type.base_type)) {
text += GenTypeBasic(element_type, IsEnum(element_type));
} else {
switch (element_type.base_type) {
case BASE_TYPE_STRING: {
text += "char";
break;
}
case BASE_TYPE_STRUCT: {
FLATBUFFERS_ASSERT(type.struct_def);
text += WrapInNameSpace(*type.struct_def);
break;
}
default:
FLATBUFFERS_ASSERT(false && "unexpected element's type");
break;
}
}
if (extent != flatbuffers::dynamic_extent) {
text += ", ";
text += NumToString(extent);
}
text += "> ";
return text;
}
std::string GenEnumValDecl(const EnumDef &enum_def,
const std::string &enum_val) const {
return opts_.prefixed_enums ? Name(enum_def) + "_" + enum_val : enum_val;
}
std::string GetEnumValUse(const EnumDef &enum_def,
const EnumVal &enum_val) const {
if (opts_.scoped_enums) {
return Name(enum_def) + "::" + Name(enum_val);
} else if (opts_.prefixed_enums) {
return Name(enum_def) + "_" + Name(enum_val);
} else {
return Name(enum_val);
}
}
std::string StripUnionType(const std::string &name) {
return name.substr(0, name.size() - strlen(UnionTypeFieldSuffix()));
}
std::string GetUnionElement(const EnumVal &ev, bool native_type,
const IDLOptions &opts) {
if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
auto name = ev.union_type.struct_def->name;
if (native_type) {
name = NativeName(name, ev.union_type.struct_def, opts);
}
return WrapInNameSpace(ev.union_type.struct_def->defined_namespace, name);
} else if (IsString(ev.union_type)) {
return native_type ? "std::string" : "flatbuffers::String";
} else {
FLATBUFFERS_ASSERT(false);