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Copy pathidl_gen_cpp.cpp
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2234 lines (2009 loc) · 81.6 KB
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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 "flatbuffers/flatbuffers.h"
#include "flatbuffers/idl.h"
#include "flatbuffers/util.h"
#include "flatbuffers/code_generators.h"
namespace flatbuffers {
// Pedantic warning free version of toupper().
inline char ToUpper(char c) {
return static_cast<char>(::toupper(c));
}
static std::string GeneratedFileName(const std::string &path,
const std::string &file_name) {
return path + file_name + "_generated.h";
}
namespace cpp {
class CppGenerator : public BaseGenerator {
public:
CppGenerator(const Parser &parser, const std::string &path,
const std::string &file_name)
: BaseGenerator(parser, path, file_name, "", "::"),
cur_name_space_(nullptr) {}
std::string GenIncludeGuard() const {
// 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) { return !isalnum(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.
auto name_space = parser_.namespaces_.back();
for (auto it = name_space->components.begin();
it != name_space->components.end(); ++it) {
guard += *it + "_";
}
guard += "H_";
std::transform(guard.begin(), guard.end(), guard.begin(), ToUpper);
return guard;
}
void GenIncludeDependencies() {
int num_includes = 0;
for (auto it = parser_.native_included_files_.begin();
it != parser_.native_included_files_.end(); ++it) {
code_ += "#include \"" + *it + "\"";
num_includes++;
}
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_ += "#include \"" + parser_.opts.include_prefix +
(parser_.opts.keep_include_path ? noext : basename) +
"_generated.h\"";
num_includes++;
}
if (num_includes) code_ += "";
}
// 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();
code_ += "#ifndef " + include_guard;
code_ += "#define " + include_guard;
code_ += "";
code_ += "#include \"flatbuffers/flatbuffers.h\"";
if (parser_.uses_flexbuffers_) {
code_ += "#include \"flatbuffers/flexbuffers.h\"";
}
code_ += "";
if (parser_.opts.include_dependence_headers) {
GenIncludeDependencies();
}
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 " + struct_def.name + ";";
if (parser_.opts.generate_object_based_api && !struct_def.fixed) {
code_ += "struct " + NativeName(struct_def.name, &struct_def) + ";";
}
code_ += "";
}
}
// Generate code for all the enum declarations.
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);
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 convenient global helper functions:
if (parser_.root_struct_def_) {
auto &struct_def = *parser_.root_struct_def_;
SetNameSpace(struct_def.defined_namespace);
const auto &name = struct_def.name;
const auto qualified_name =
parser_.namespaces_.back()->GetFullyQualifiedName(name);
const auto cpp_name = TranslateNameSpace(qualified_name);
code_.SetValue("STRUCT_NAME", name);
code_.SetValue("CPP_NAME", cpp_name);
// The root datatype accessor:
code_ += "inline \\";
code_ += "const {{CPP_NAME}} *Get{{STRUCT_NAME}}(const void *buf) {";
code_ += " return flatbuffers::GetRoot<{{CPP_NAME}}>(buf);";
code_ += "}";
code_ += "";
if (parser_.opts.mutable_buffer) {
code_ += "inline \\";
code_ += "{{STRUCT_NAME}} *GetMutable{{STRUCT_NAME}}(void *buf) {";
code_ += " return flatbuffers::GetMutableRoot<{{STRUCT_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_ += "";
}
// 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_ += "";
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_ += "";
if (parser_.opts.generate_object_based_api) {
// A convenient root unpack function.
auto native_name =
NativeName(WrapInNameSpace(struct_def), &struct_def);
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_ += "";
}
}
if (cur_name_space_) SetNameSpace(nullptr);
// Close the include guard.
code_ += "#endif // " + include_guard;
const auto file_path = GeneratedFileName(path_, file_name_);
const auto final_code = code_.ToString();
return SaveFile(file_path.c_str(), final_code, false);
}
private:
CodeWriter code_;
// This tracks the current namespace so we can insert namespace declarations.
const Namespace *cur_name_space_;
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;
}
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 {
static const char *ctypename[] = {
#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE) \
#CTYPE,
FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
#undef FLATBUFFERS_TD
};
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(), "", false);
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";
}
}
// TODO(wvo): make this configurable.
static std::string NativeName(const std::string &name, const StructDef *sd) {
return sd && !sd->fixed ? name + "T" : name;
}
const std::string &PtrType(const FieldDef *field) {
auto attr = field ? field->attributes.Lookup("cpp_ptr_type") : nullptr;
return attr ? attr->constant : parser_.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 : parser_.opts.cpp_object_api_string_type;
if (ret.empty()) {
return "std::string";
}
return ret;
}
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 + "<" + type + ">";
} else if (is_constructor) {
return "";
} else {
return type + " *";
}
}
std::string GenPtrGet(const FieldDef &field) {
auto &ptr_type = PtrType(&field);
return ptr_type == "naked" ? "" : ".get()";
}
std::string GenTypeNative(const Type &type, bool invector,
const FieldDef &field) {
switch (type.base_type) {
case BASE_TYPE_STRING: {
return NativeString(&field);
}
case BASE_TYPE_VECTOR: {
const auto type_name = GenTypeNative(type.VectorType(), true, field);
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) {
return type_name;
} else {
return GenTypeNativePtr(type_name, &field, false);
}
} else {
return GenTypeNativePtr(NativeName(type_name, type.struct_def),
&field, false);
}
}
case BASE_TYPE_UNION: {
return type.enum_def->name + "Union";
}
default: {
return 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 {
return beforeptr + GenTypePointer(type) + afterptr;
}
}
std::string GenEnumDecl(const EnumDef &enum_def) const {
const IDLOptions &opts = parser_.opts;
return (opts.scoped_enums ? "enum class " : "enum ") + enum_def.name;
}
std::string GenEnumValDecl(const EnumDef &enum_def,
const std::string &enum_val) const {
const IDLOptions &opts = parser_.opts;
return opts.prefixed_enums ? enum_def.name + "_" + enum_val : enum_val;
}
std::string GetEnumValUse(const EnumDef &enum_def,
const EnumVal &enum_val) const {
const IDLOptions &opts = parser_.opts;
if (opts.scoped_enums) {
return enum_def.name + "::" + enum_val.name;
} else if (opts.prefixed_enums) {
return enum_def.name + "_" + enum_val.name;
} else {
return enum_val.name;
}
}
std::string StripUnionType(const std::string &name) {
return name.substr(0, name.size() - strlen(UnionTypeFieldSuffix()));
}
std::string GetUnionElement(const EnumVal &ev, bool wrap, bool actual_type,
bool native_type = false) {
if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
auto name = actual_type ? ev.union_type.struct_def->name : ev.name;
return wrap
? WrapInNameSpace(ev.union_type.struct_def->defined_namespace, name)
: name;
} else if (ev.union_type.base_type == BASE_TYPE_STRING) {
return actual_type
? (native_type ? "std::string" : "flatbuffers::String")
: ev.name;
} else {
assert(false);
return ev.name;
}
}
static std::string UnionVerifySignature(const EnumDef &enum_def) {
return "bool Verify" + enum_def.name +
"(flatbuffers::Verifier &verifier, const void *obj, " +
enum_def.name + " type)";
}
static std::string UnionVectorVerifySignature(const EnumDef &enum_def) {
return "bool Verify" + enum_def.name + "Vector" +
"(flatbuffers::Verifier &verifier, " +
"const flatbuffers::Vector<flatbuffers::Offset<void>> *values, " +
"const flatbuffers::Vector<uint8_t> *types)";
}
static std::string UnionUnPackSignature(const EnumDef &enum_def,
bool inclass) {
return (inclass ? "static " : "") +
std::string("void *") +
(inclass ? "" : enum_def.name + "Union::") +
"UnPack(const void *obj, " + enum_def.name +
" type, const flatbuffers::resolver_function_t *resolver)";
}
static std::string UnionPackSignature(const EnumDef &enum_def, bool inclass) {
return "flatbuffers::Offset<void> " +
(inclass ? "" : enum_def.name + "Union::") +
"Pack(flatbuffers::FlatBufferBuilder &_fbb, " +
"const flatbuffers::rehasher_function_t *_rehasher" +
(inclass ? " = nullptr" : "") + ") const";
}
static std::string TableCreateSignature(const StructDef &struct_def,
bool predecl) {
return "flatbuffers::Offset<" + struct_def.name + "> Create" +
struct_def.name +
"(flatbuffers::FlatBufferBuilder &_fbb, const " +
NativeName(struct_def.name, &struct_def) +
" *_o, const flatbuffers::rehasher_function_t *_rehasher" +
(predecl ? " = nullptr" : "") + ")";
}
static std::string TablePackSignature(const StructDef &struct_def,
bool inclass) {
return std::string(inclass ? "static " : "") +
"flatbuffers::Offset<" + struct_def.name + "> " +
(inclass ? "" : struct_def.name + "::") +
"Pack(flatbuffers::FlatBufferBuilder &_fbb, " +
"const " + NativeName(struct_def.name, &struct_def) + "* _o, " +
"const flatbuffers::rehasher_function_t *_rehasher" +
(inclass ? " = nullptr" : "") + ")";
}
static std::string TableUnPackSignature(const StructDef &struct_def,
bool inclass) {
return NativeName(struct_def.name, &struct_def) + " *" +
(inclass ? "" : struct_def.name + "::") +
"UnPack(const flatbuffers::resolver_function_t *_resolver" +
(inclass ? " = nullptr" : "") + ") const";
}
static std::string TableUnPackToSignature(const StructDef &struct_def,
bool inclass) {
return "void " + (inclass ? "" : struct_def.name + "::") +
"UnPackTo(" + NativeName(struct_def.name, &struct_def) + " *" +
"_o, const flatbuffers::resolver_function_t *_resolver" +
(inclass ? " = nullptr" : "") + ") const";
}
// Generate an enum declaration,
// an enum string lookup table,
// and an enum array of values
void GenEnum(const EnumDef &enum_def) {
code_.SetValue("ENUM_NAME", enum_def.name);
code_.SetValue("BASE_TYPE", GenTypeBasic(enum_def.underlying_type, false));
code_.SetValue("SEP", "");
GenComment(enum_def.doc_comment);
code_ += GenEnumDecl(enum_def) + "\\";
if (parser_.opts.scoped_enums)
code_ += " : {{BASE_TYPE}}\\";
code_ += " {";
int64_t anyv = 0;
const EnumVal *minv = nullptr, *maxv = nullptr;
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
GenComment(ev.doc_comment, " ");
code_.SetValue("KEY", GenEnumValDecl(enum_def, ev.name));
code_.SetValue("VALUE", NumToString(ev.value));
code_ += "{{SEP}} {{KEY}} = {{VALUE}}\\";
code_.SetValue("SEP", ",\n");
minv = !minv || minv->value > ev.value ? &ev : minv;
maxv = !maxv || maxv->value < ev.value ? &ev : maxv;
anyv |= ev.value;
}
if (parser_.opts.scoped_enums || parser_.opts.prefixed_enums) {
assert(minv && maxv);
code_.SetValue("SEP", ",\n");
if (enum_def.attributes.Lookup("bit_flags")) {
code_.SetValue("KEY", GenEnumValDecl(enum_def, "NONE"));
code_.SetValue("VALUE", "0");
code_ += "{{SEP}} {{KEY}} = {{VALUE}}\\";
code_.SetValue("KEY", GenEnumValDecl(enum_def, "ANY"));
code_.SetValue("VALUE", NumToString(anyv));
code_ += "{{SEP}} {{KEY}} = {{VALUE}}\\";
} else { // MIN & MAX are useless for bit_flags
code_.SetValue("KEY",GenEnumValDecl(enum_def, "MIN"));
code_.SetValue("VALUE", GenEnumValDecl(enum_def, minv->name));
code_ += "{{SEP}} {{KEY}} = {{VALUE}}\\";
code_.SetValue("KEY",GenEnumValDecl(enum_def, "MAX"));
code_.SetValue("VALUE", GenEnumValDecl(enum_def, maxv->name));
code_ += "{{SEP}} {{KEY}} = {{VALUE}}\\";
}
}
code_ += "";
code_ += "};";
if (parser_.opts.scoped_enums && enum_def.attributes.Lookup("bit_flags")) {
code_ += "DEFINE_BITMASK_OPERATORS({{ENUM_NAME}}, {{BASE_TYPE}})";
}
code_ += "";
// Generate an array of all enumeration values
auto num_fields = NumToString(enum_def.vals.vec.size());
code_ += "inline {{ENUM_NAME}} (&EnumValues{{ENUM_NAME}}())[" + num_fields + "] {";
code_ += " static {{ENUM_NAME}} values[] = {";
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
auto value = GetEnumValUse(enum_def, ev);
auto suffix = *it != enum_def.vals.vec.back() ? "," : "";
code_ += " " + value + suffix;
}
code_ += " };";
code_ += " return values;";
code_ += "}";
code_ += "";
// Generate a generate string table for enum values.
// Problem is, if values are very sparse that could generate really big
// tables. Ideally in that case we generate a map lookup instead, but for
// the moment we simply don't output a table at all.
auto range =
enum_def.vals.vec.back()->value - enum_def.vals.vec.front()->value + 1;
// Average distance between values above which we consider a table
// "too sparse". Change at will.
static const int kMaxSparseness = 5;
if (range / static_cast<int64_t>(enum_def.vals.vec.size()) <
kMaxSparseness) {
code_ += "inline const char **EnumNames{{ENUM_NAME}}() {";
code_ += " static const char *names[] = {";
auto val = enum_def.vals.vec.front()->value;
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
while (val++ != ev.value) {
code_ += " \"\",";
}
code_ += " \"" + ev.name + "\",";
}
code_ += " nullptr";
code_ += " };";
code_ += " return names;";
code_ += "}";
code_ += "";
code_ += "inline const char *EnumName{{ENUM_NAME}}({{ENUM_NAME}} e) {";
code_ += " const size_t index = static_cast<int>(e)\\";
if (enum_def.vals.vec.front()->value) {
auto vals = GetEnumValUse(enum_def, *enum_def.vals.vec.front());
code_ += " - static_cast<int>(" + vals + ")\\";
}
code_ += ";";
code_ += " return EnumNames{{ENUM_NAME}}()[index];";
code_ += "}";
code_ += "";
}
// Generate type traits for unions to map from a type to union enum value.
if (enum_def.is_union && !enum_def.uses_type_aliases) {
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
if (it == enum_def.vals.vec.begin()) {
code_ += "template<typename T> struct {{ENUM_NAME}}Traits {";
}
else {
auto name = GetUnionElement(ev, true, true);
code_ += "template<> struct {{ENUM_NAME}}Traits<" + name + "> {";
}
auto value = GetEnumValUse(enum_def, ev);
code_ += " static const {{ENUM_NAME}} enum_value = " + value + ";";
code_ += "};";
code_ += "";
}
}
if (parser_.opts.generate_object_based_api && enum_def.is_union) {
// Generate a union type
code_.SetValue("NAME", enum_def.name);
code_.SetValue("NONE",
GetEnumValUse(enum_def, *enum_def.vals.Lookup("NONE")));
code_ += "struct {{NAME}}Union {";
code_ += " {{NAME}} type;";
code_ += " void *value;";
code_ += "";
code_ += " {{NAME}}Union() : type({{NONE}}), value(nullptr) {}";
code_ += " {{NAME}}Union({{NAME}}Union&& u) FLATBUFFERS_NOEXCEPT :";
code_ += " type({{NONE}}), value(nullptr)";
code_ += " { std::swap(type, u.type); std::swap(value, u.value); }";
code_ += " {{NAME}}Union(const {{NAME}}Union &) FLATBUFFERS_NOEXCEPT;";
code_ += " {{NAME}}Union &operator=(const {{NAME}}Union &u) FLATBUFFERS_NOEXCEPT";
code_ += " { {{NAME}}Union t(u); std::swap(type, t.type); std::swap(value, t.value); return *this; }";
code_ += " {{NAME}}Union &operator=({{NAME}}Union &&u) FLATBUFFERS_NOEXCEPT";
code_ += " { std::swap(type, u.type); std::swap(value, u.value); return *this; }";
code_ += " ~{{NAME}}Union() { Reset(); }";
code_ += "";
code_ += " void Reset();";
code_ += "";
if (!enum_def.uses_type_aliases) {
code_ += " template <typename T>";
code_ += " void Set(T&& val) {";
code_ += " Reset();";
code_ += " type = {{NAME}}Traits<typename T::TableType>::enum_value;";
code_ += " if (type != {{NONE}}) {";
code_ += " value = new T(std::forward<T>(val));";
code_ += " }";
code_ += " }";
code_ += "";
}
code_ += " " + UnionUnPackSignature(enum_def, true) + ";";
code_ += " " + UnionPackSignature(enum_def, true) + ";";
code_ += "";
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
if (!ev.value) {
continue;
}
const auto native_type =
NativeName(GetUnionElement(ev, true, true, true),
ev.union_type.struct_def);
code_.SetValue("NATIVE_TYPE", native_type);
code_.SetValue("NATIVE_NAME", ev.name);
code_.SetValue("NATIVE_ID", GetEnumValUse(enum_def, ev));
code_ += " {{NATIVE_TYPE}} *As{{NATIVE_NAME}}() {";
code_ += " return type == {{NATIVE_ID}} ?";
code_ += " reinterpret_cast<{{NATIVE_TYPE}} *>(value) : nullptr;";
code_ += " }";
}
code_ += "};";
code_ += "";
}
if (enum_def.is_union) {
code_ += UnionVerifySignature(enum_def) + ";";
code_ += UnionVectorVerifySignature(enum_def) + ";";
code_ += "";
}
}
void GenUnionPost(const EnumDef &enum_def) {
// Generate a verifier function for this union that can be called by the
// table verifier functions. It uses a switch case to select a specific
// verifier function to call, this should be safe even if the union type
// has been corrupted, since the verifiers will simply fail when called
// on the wrong type.
code_.SetValue("ENUM_NAME", enum_def.name);
code_ += "inline " + UnionVerifySignature(enum_def) + " {";
code_ += " switch (type) {";
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
if (ev.value) {
code_.SetValue("TYPE", GetUnionElement(ev, true, true));
code_ += " case {{LABEL}}: {";
auto getptr =
" auto ptr = reinterpret_cast<const {{TYPE}} *>(obj);";
if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
if (ev.union_type.struct_def->fixed) {
code_ += " return true;";
} else {
code_ += getptr;
code_ += " return verifier.VerifyTable(ptr);";
}
} else if (ev.union_type.base_type == BASE_TYPE_STRING) {
code_ += getptr;
code_ += " return verifier.Verify(ptr);";
} else {
assert(false);
}
code_ += " }";
} else {
code_ += " case {{LABEL}}: {";
code_ += " return true;"; // "NONE" enum value.
code_ += " }";
}
}
code_ += " default: return false;";
code_ += " }";
code_ += "}";
code_ += "";
code_ += "inline " + UnionVectorVerifySignature(enum_def) + " {";
code_ += " if (values->size() != types->size()) return false;";
code_ += " for (flatbuffers::uoffset_t i = 0; i < values->size(); ++i) {";
code_ += " if (!Verify" + enum_def.name + "(";
code_ += " verifier, values->Get(i), types->GetEnum<" + enum_def.name + ">(i))) {";
code_ += " return false;";
code_ += " }";
code_ += " }";
code_ += " return true;";
code_ += "}";
code_ += "";
if (parser_.opts.generate_object_based_api) {
// Generate union Unpack() and Pack() functions.
code_ += "inline " + UnionUnPackSignature(enum_def, false) + " {";
code_ += " switch (type) {";
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
if (!ev.value) {
continue;
}
code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
code_.SetValue("TYPE", GetUnionElement(ev, true, true));
code_ += " case {{LABEL}}: {";
code_ += " auto ptr = reinterpret_cast<const {{TYPE}} *>(obj);";
if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
if (ev.union_type.struct_def->fixed) {
code_ += " return new " +
WrapInNameSpace(*ev.union_type.struct_def) + "(*ptr);";
} else {
code_ += " return ptr->UnPack(resolver);";
}
} else if (ev.union_type.base_type == BASE_TYPE_STRING) {
code_ += " return new std::string(ptr->c_str(), ptr->size());";
} else {
assert(false);
}
code_ += " }";
}
code_ += " default: return nullptr;";
code_ += " }";
code_ += "}";
code_ += "";
code_ += "inline " + UnionPackSignature(enum_def, false) + " {";
code_ += " switch (type) {";
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
auto &ev = **it;
if (!ev.value) {
continue;
}
code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
code_.SetValue("TYPE", NativeName(GetUnionElement(ev, true, true, true),
ev.union_type.struct_def));
code_.SetValue("NAME", GetUnionElement(ev, false, true));
code_ += " case {{LABEL}}: {";
code_ += " auto ptr = reinterpret_cast<const {{TYPE}} *>(value);";
if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
if (ev.union_type.struct_def->fixed) {
code_ += " return _fbb.CreateStruct(*ptr).Union();";
} else {
code_ +=
" return Create{{NAME}}(_fbb, ptr, _rehasher).Union();";
}
} else if (ev.union_type.base_type == BASE_TYPE_STRING) {
code_ += " return _fbb.CreateString(*ptr).Union();";
} else {
assert(false);
}
code_ += " }";
}
code_ += " default: return 0;";
code_ += " }";
code_ += "}";
code_ += "";
// Union copy constructor
code_ += "inline {{ENUM_NAME}}Union::{{ENUM_NAME}}Union(const "
"{{ENUM_NAME}}Union &u) FLATBUFFERS_NOEXCEPT : type(u.type), "
"value(nullptr) {";
code_ += " switch (type) {";
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
if (!ev.value) {
continue;
}
code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
code_.SetValue("TYPE", NativeName(GetUnionElement(ev, true, true, true),
ev.union_type.struct_def));
code_ += " case {{LABEL}}: {";
bool copyable = true;
if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
// Don't generate code to copy if table is not copyable.
// TODO(wvo): make tables copyable instead.
for (auto fit = ev.union_type.struct_def->fields.vec.begin();
fit != ev.union_type.struct_def->fields.vec.end(); ++fit) {
const auto &field = **fit;
if (!field.deprecated && field.value.type.struct_def) {
copyable = false;
break;
}
}
}
if (copyable) {
code_ += " value = new {{TYPE}}(*reinterpret_cast<{{TYPE}} *>"
"(u.value));";
} else {
code_ += " assert(false); // {{TYPE}} not copyable.";
}
code_ += " break;";
code_ += " }";
}
code_ += " default:";
code_ += " break;";
code_ += " }";
code_ += "}";
code_ += "";
// Union Reset() function.
code_.SetValue("NONE",
GetEnumValUse(enum_def, *enum_def.vals.Lookup("NONE")));
code_ += "inline void {{ENUM_NAME}}Union::Reset() {";
code_ += " switch (type) {";
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
++it) {
const auto &ev = **it;
if (!ev.value) {
continue;
}
code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
code_.SetValue("TYPE", NativeName(GetUnionElement(ev, true, true, true),
ev.union_type.struct_def));
code_ += " case {{LABEL}}: {";
code_ += " auto ptr = reinterpret_cast<{{TYPE}} *>(value);";
code_ += " delete ptr;";
code_ += " break;";
code_ += " }";
}
code_ += " default: break;";
code_ += " }";
code_ += " value = nullptr;";
code_ += " type = {{NONE}};";
code_ += "}";
code_ += "";
}
}
// Generates a value with optionally a cast applied if the field has a
// different underlying type from its interface type (currently only the
// case for enums. "from" specify the direction, true meaning from the
// underlying type to the interface type.
std::string GenUnderlyingCast(const FieldDef &field, bool from,
const std::string &val) {
if (from && field.value.type.base_type == BASE_TYPE_BOOL) {
return val + " != 0";
} else if ((field.value.type.enum_def &&
IsScalar(field.value.type.base_type)) ||
field.value.type.base_type == BASE_TYPE_BOOL) {
return "static_cast<" + GenTypeBasic(field.value.type, from) + ">(" +
val + ")";
} else {
return val;
}
}
std::string GenFieldOffsetName(const FieldDef &field) {
std::string uname = field.name;
std::transform(uname.begin(), uname.end(), uname.begin(), ToUpper);
return "VT_" + uname;
}
void GenFullyQualifiedNameGetter(const std::string &name) {
if (!parser_.opts.generate_name_strings) {
return;
}
auto fullname = parser_.namespaces_.back()->GetFullyQualifiedName(name);
code_.SetValue("NAME", fullname);
code_.SetValue("CONSTEXPR", "FLATBUFFERS_CONSTEXPR");
code_ += " static {{CONSTEXPR}} const char *GetFullyQualifiedName() {";