/*
* 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 "idl_gen_python.h"
#include <cctype>
#include <set>
#include <string>
#include <unordered_set>
#include <vector>
#include "flatbuffers/code_generators.h"
#include "flatbuffers/flatbuffers.h"
#include "flatbuffers/idl.h"
#include "flatbuffers/util.h"
#include "idl_namer.h"
namespace flatbuffers {
namespace python {
namespace {
typedef std::pair<std::string, std::string> ImportMapEntry;
typedef std::set<ImportMapEntry> ImportMap;
static std::set<std::string> PythonKeywords() {
return { "False", "None", "True", "and", "as", "assert",
"break", "class", "continue", "def", "del", "elif",
"else", "except", "finally", "for", "from", "global",
"if", "import", "in", "is", "lambda", "nonlocal",
"not", "or", "pass", "raise", "return", "try",
"while", "with", "yield" };
}
static Namer::Config PythonDefaultConfig() {
return { /*types=*/Case::kKeep,
/*constants=*/Case::kScreamingSnake,
/*methods=*/Case::kUpperCamel,
/*functions=*/Case::kUpperCamel,
/*fields=*/Case::kLowerCamel,
/*variable=*/Case::kLowerCamel,
/*variants=*/Case::kKeep,
/*enum_variant_seperator=*/".",
/*escape_keywords=*/Namer::Config::Escape::BeforeConvertingCase,
/*namespaces=*/Case::kKeep, // Packages in python.
/*namespace_seperator=*/".",
/*object_prefix=*/"",
/*object_suffix=*/"T",
/*keyword_prefix=*/"",
/*keyword_suffix=*/"_",
/*filenames=*/Case::kKeep,
/*directories=*/Case::kKeep,
/*output_path=*/"",
/*filename_suffix=*/"",
/*filename_extension=*/".py" };
}
// Hardcode spaces per indentation.
static const CommentConfig def_comment = { nullptr, "#", nullptr };
static const std::string Indent = " ";
} // namespace
class PythonGenerator : public BaseGenerator {
public:
PythonGenerator(const Parser &parser, const std::string &path,
const std::string &file_name)
: BaseGenerator(parser, path, file_name, "" /* not used */,
"" /* not used */, "py"),
float_const_gen_("float('nan')", "float('inf')", "float('-inf')"),
namer_(WithFlagOptions(PythonDefaultConfig(), parser.opts, path),
PythonKeywords()) {}
// Most field accessors need to retrieve and test the field offset first,
// this is the prefix code for that.
std::string OffsetPrefix(const FieldDef &field, bool new_line = true) const {
return "\n" + Indent + Indent +
"o = flatbuffers.number_types.UOffsetTFlags.py_type" +
"(self._tab.Offset(" + NumToString(field.value.offset) + "))\n" +
Indent + Indent + "if o != 0:" + (new_line ? "\n" : "");
}
// Begin a class declaration.
void BeginClass(const StructDef &struct_def, std::string *code_ptr) const {
auto &code = *code_ptr;
code += "class " + namer_.Type(struct_def) + "(object):\n";
code += Indent + "__slots__ = ['_tab']";
code += "\n\n";
}
// Begin enum code with a class declaration.
void BeginEnum(const EnumDef &enum_def, std::string *code_ptr) const {
auto &code = *code_ptr;
code += "class " + namer_.Type(enum_def) + "(object):\n";
}
// Starts a new line and then indents.
std::string GenIndents(int num) const {
return "\n" + std::string(num * Indent.length(), ' ');
}
// A single enum member.
void EnumMember(const EnumDef &enum_def, const EnumVal &ev,
std::string *code_ptr) const {
auto &code = *code_ptr;
code += Indent;
code += namer_.Variant(ev);
code += " = ";
code += enum_def.ToString(ev) + "\n";
}
// Initialize a new struct or table from existing data.
void NewRootTypeFromBuffer(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
const std::string struct_type = namer_.Type(struct_def);
code += Indent + "@classmethod\n";
code += Indent + "def GetRootAs";
if (parser_.opts.python_typing) {
code += "(cls, buf, offset: int = 0):";
} else {
code += "(cls, buf, offset=0):";
}
code += "\n";
code += Indent + Indent;
code += "n = flatbuffers.encode.Get";
code += "(flatbuffers.packer.uoffset, buf, offset)\n";
code += Indent + Indent + "x = " + struct_type + "()\n";
code += Indent + Indent + "x.Init(buf, n + offset)\n";
code += Indent + Indent + "return x\n";
code += "\n";
if (!parser_.opts.python_no_type_prefix_suffix) {
// Add an alias with the old name
code += Indent + "@classmethod\n";
code +=
Indent + "def GetRootAs" + struct_type + "(cls, buf, offset=0):\n";
code += Indent + Indent +
"\"\"\"This method is deprecated. Please switch to "
"GetRootAs.\"\"\"\n";
code += Indent + Indent + "return cls.GetRootAs(buf, offset)\n";
}
}
// Initialize an existing object with other data, to avoid an allocation.
void InitializeExisting(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
if (parser_.opts.python_typing) {
code += "Init(self, buf: bytes, pos: int):\n";
} else {
code += "Init(self, buf, pos):\n";
}
code += Indent + Indent + "self._tab = flatbuffers.table.Table(buf, pos)\n";
code += "\n";
}
// Get the length of a vector.
void GetVectorLen(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field) + "Length(self)";
if (parser_.opts.python_typing) { code += " -> int"; }
code += ":";
if (!IsArray(field.value.type)) {
code += OffsetPrefix(field, false);
code += GenIndents(3) + "return self._tab.VectorLen(o)";
code += GenIndents(2) + "return 0\n\n";
} else {
code += GenIndents(2) + "return " +
NumToString(field.value.type.fixed_length) + "\n\n";
}
}
// Determines whether a vector is none or not.
void GetVectorIsNone(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field) + "IsNone(self)";
if (parser_.opts.python_typing) { code += " -> bool"; }
code += ":";
if (!IsArray(field.value.type)) {
code += GenIndents(2) +
"o = flatbuffers.number_types.UOffsetTFlags.py_type" +
"(self._tab.Offset(" + NumToString(field.value.offset) + "))";
code += GenIndents(2) + "return o == 0";
} else {
// assume that we always have an array as memory is preassigned
code += GenIndents(2) + "return False";
}
code += "\n\n";
}
// Get the value of a struct's scalar.
void GetScalarFieldOfStruct(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
std::string getter = GenGetter(field.value.type);
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
code += "(self): return " + getter;
code += "self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(";
code += NumToString(field.value.offset) + "))\n";
}
// Get the value of a table's scalar.
void GetScalarFieldOfTable(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
std::string getter = GenGetter(field.value.type);
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
code += "(self):";
code += OffsetPrefix(field);
getter += "o + self._tab.Pos)";
auto is_bool = IsBool(field.value.type.base_type);
if (is_bool) { getter = "bool(" + getter + ")"; }
code += Indent + Indent + Indent + "return " + getter + "\n";
std::string default_value;
if (field.IsScalarOptional()) {
default_value = "None";
} else if (is_bool) {
default_value = field.value.constant == "0" ? "False" : "True";
} else {
default_value = IsFloat(field.value.type.base_type)
? float_const_gen_.GenFloatConstant(field)
: field.value.constant;
}
code += Indent + Indent + "return " + default_value + "\n\n";
}
// Get a struct by initializing an existing struct.
// Specific to Struct.
void GetStructFieldOfStruct(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
code += "(self, obj):\n";
code += Indent + Indent + "obj.Init(self._tab.Bytes, self._tab.Pos + ";
code += NumToString(field.value.offset) + ")";
code += "\n" + Indent + Indent + "return obj\n\n";
}
// Get the value of a fixed size array.
void GetArrayOfStruct(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr, ImportMap &imports) const {
auto &code = *code_ptr;
const auto vec_type = field.value.type.VectorType();
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
const ImportMapEntry import_entry = {
GenPackageReference(field.value.type), TypeName(field)
};
if (parser_.opts.python_typing) {
const std::string return_type = ReturnType(struct_def, field);
code += "(self, i: int)";
code += " -> " + return_type + ":";
imports.insert(import_entry);
} else {
code += "(self, i):";
}
if (parser_.opts.include_dependence_headers &&
!parser_.opts.python_typing) {
code += GenIndents(2);
code += "from " + import_entry.first + " import " + import_entry.second +
"\n";
}
code += GenIndents(2) + "obj = " + TypeName(field) + "()";
code += GenIndents(2) + "obj.Init(self._tab.Bytes, self._tab.Pos + ";
code += NumToString(field.value.offset) + " + i * ";
code += NumToString(InlineSize(vec_type));
code += ")" + GenIndents(2) + "return obj\n\n";
}
// Get the value of a vector's non-struct member. Uses a named return
// argument to conveniently set the zero value for the result.
void GetArrayOfNonStruct(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
code += "(self, j = None):";
code += GenIndents(2) + "if j is None:";
code += GenIndents(3) + "return [" + GenGetter(field.value.type);
code += "self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(";
code += NumToString(field.value.offset) + " + i * ";
code += NumToString(InlineSize(field.value.type.VectorType()));
code += ")) for i in range(";
code += "self." + namer_.Method(field) + "Length()" + ")]";
code += GenIndents(2) + "elif j >= 0 and j < self." + namer_.Method(field) +
"Length():";
code += GenIndents(3) + "return " + GenGetter(field.value.type);
code += "self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(";
code += NumToString(field.value.offset) + " + j * ";
code += NumToString(InlineSize(field.value.type.VectorType()));
code += "))";
code += GenIndents(2) + "else:";
code += GenIndents(3) + "return None\n\n";
}
// Get a struct by initializing an existing struct.
// Specific to Table.
void GetStructFieldOfTable(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr, ImportMap &imports) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field) + "(self)";
const ImportMapEntry import_entry = {
GenPackageReference(field.value.type), TypeName(field)
};
if (parser_.opts.python_typing) {
const std::string return_type = ReturnType(struct_def, field);
code += " -> Optional[" + return_type + "]";
imports.insert(ImportMapEntry{ "typing", "Optional" });
imports.insert(import_entry);
}
code += ":";
code += OffsetPrefix(field);
if (field.value.type.struct_def->fixed) {
code += Indent + Indent + Indent + "x = o + self._tab.Pos\n";
} else {
code += Indent + Indent + Indent;
code += "x = self._tab.Indirect(o + self._tab.Pos)\n";
}
if (parser_.opts.include_dependence_headers &&
!parser_.opts.python_typing) {
code += Indent + Indent + Indent;
code += "from " + import_entry.first + " import " + import_entry.second +
"\n";
}
code += Indent + Indent + Indent + "obj = " + TypeName(field) + "()\n";
code += Indent + Indent + Indent + "obj.Init(self._tab.Bytes, x)\n";
code += Indent + Indent + Indent + "return obj\n";
code += Indent + Indent + "return None\n\n";
}
// Get the value of a string.
void GetStringField(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr, ImportMap &imports) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
if (parser_.opts.python_typing) {
code += "(self) -> Optional[str]:";
imports.insert(ImportMapEntry{ "typing", "Optional" });
} else {
code += "(self):";
}
code += OffsetPrefix(field);
code += Indent + Indent + Indent + "return " + GenGetter(field.value.type);
code += "o + self._tab.Pos)\n";
code += Indent + Indent + "return None\n\n";
}
// Get the value of a union from an object.
void GetUnionField(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr, ImportMap &imports) const {
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
std::string return_ty = "flatbuffers.table.Table";
bool is_native_table = TypeName(field) == "*flatbuffers.Table";
ImportMapEntry import_entry;
if (is_native_table) {
import_entry = ImportMapEntry{ "flatbuffers.table", "Table" };
} else {
return_ty = TypeName(field);
import_entry = ImportMapEntry{ GenPackageReference(field.value.type),
TypeName(field) };
}
code += namer_.Method(field) + "(self)";
if (parser_.opts.python_typing) {
code += " -> Optional[" + return_ty + "]";
imports.insert(ImportMapEntry{ "typing", "Optional" });
imports.insert(import_entry);
}
code += ":";
code += OffsetPrefix(field);
if (!parser_.opts.python_typing) {
code += Indent + Indent + Indent;
code += "from " + import_entry.first + " import " + import_entry.second +
"\n";
}
code += Indent + Indent + Indent + "obj = Table(bytearray(), 0)\n";
code += Indent + Indent + Indent + GenGetter(field.value.type);
code += "obj, o)\n" + Indent + Indent + Indent + "return obj\n";
code += Indent + Indent + "return None\n\n";
}
// Generate the package reference when importing a struct or enum from its
// module.
std::string GenPackageReference(const Type &type) const {
if (type.struct_def) {
return namer_.NamespacedType(*type.struct_def);
} else if (type.enum_def) {
return namer_.NamespacedType(*type.enum_def);
} else {
return "." + GenTypeGet(type);
}
}
// Get the value of a vector's struct member.
void GetMemberOfVectorOfStruct(const StructDef &struct_def,
const FieldDef &field, std::string *code_ptr,
ImportMap &imports) const {
auto &code = *code_ptr;
auto vectortype = field.value.type.VectorType();
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
const ImportMapEntry import_entry = {
GenPackageReference(field.value.type), TypeName(field)
};
if (parser_.opts.python_typing) {
const std::string return_type = ReturnType(struct_def, field);
code += "(self, j: int) -> Optional[" + return_type + "]";
imports.insert(ImportMapEntry{ "typing", "Optional" });
imports.insert(import_entry);
} else {
code += "(self, j)";
}
code += ":" + OffsetPrefix(field);
code += Indent + Indent + Indent + "x = self._tab.Vector(o)\n";
code += Indent + Indent + Indent;
code += "x += flatbuffers.number_types.UOffsetTFlags.py_type(j) * ";
code += NumToString(InlineSize(vectortype)) + "\n";
if (!(vectortype.struct_def->fixed)) {
code += Indent + Indent + Indent + "x = self._tab.Indirect(x)\n";
}
if (parser_.opts.include_dependence_headers &&
!parser_.opts.python_typing) {
code += Indent + Indent + Indent;
code += "from " + import_entry.first + " import " + import_entry.second +
"\n";
}
code += Indent + Indent + Indent + "obj = " + TypeName(field) + "()\n";
code += Indent + Indent + Indent + "obj.Init(self._tab.Bytes, x)\n";
code += Indent + Indent + Indent + "return obj\n";
code += Indent + Indent + "return None\n\n";
}
// Get the value of a vector's non-struct member. Uses a named return
// argument to conveniently set the zero value for the result.
void GetMemberOfVectorOfNonStruct(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
auto vectortype = field.value.type.VectorType();
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field);
if (parser_.opts.python_typing) {
code += "(self, j: int)";
} else {
code += "(self, j)";
}
code += ":";
code += OffsetPrefix(field);
code += Indent + Indent + Indent + "a = self._tab.Vector(o)\n";
code += Indent + Indent + Indent;
code += "return " + GenGetter(field.value.type);
code += "a + flatbuffers.number_types.UOffsetTFlags.py_type(j * ";
code += NumToString(InlineSize(vectortype)) + "))\n";
if (IsString(vectortype)) {
code += Indent + Indent + "return \"\"\n";
} else {
code += Indent + Indent + "return 0\n";
}
code += "\n";
}
// Returns a non-struct vector as a numpy array. Much faster
// than iterating over the vector element by element.
void GetVectorOfNonStructAsNumpy(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
auto vectortype = field.value.type.VectorType();
// Currently, we only support accessing as numpy array if
// the vector type is a scalar.
if (!(IsScalar(vectortype.base_type))) { return; }
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field) + "AsNumpy(self):";
if (!IsArray(field.value.type)) {
code += OffsetPrefix(field, false);
code += GenIndents(3);
code += "return ";
code += "self._tab.GetVectorAsNumpy(flatbuffers.number_types.";
code += namer_.Method(GenTypeGet(field.value.type));
code += "Flags, o)";
if (IsString(vectortype)) {
code += GenIndents(2) + "return \"\"\n";
} else {
code += GenIndents(2) + "return 0\n";
}
} else {
code += GenIndents(2) + "return ";
code += "self._tab.GetArrayAsNumpy(flatbuffers.number_types.";
code += namer_.Method(GenTypeGet(field.value.type.VectorType()));
code += "Flags, self._tab.Pos + " + NumToString(field.value.offset) +
", " + NumToString("self." + namer_.Method(field) + "Length()") +
")\n";
}
code += "\n";
}
std::string NestedFlatbufferType(std::string unqualified_name) const {
StructDef *nested_root = parser_.LookupStruct(unqualified_name);
std::string qualified_name;
if (nested_root == nullptr) {
qualified_name = namer_.NamespacedType(
parser_.current_namespace_->components, unqualified_name);
// Double check qualified name just to be sure it exists.
nested_root = parser_.LookupStruct(qualified_name);
}
FLATBUFFERS_ASSERT(nested_root); // Guaranteed to exist by parser.
return qualified_name;
}
// Returns a nested flatbuffer as itself.
void GetVectorAsNestedFlatbuffer(const StructDef &struct_def,
const FieldDef &field, std::string *code_ptr,
ImportMap &imports) const {
auto nested = field.attributes.Lookup("nested_flatbuffer");
if (!nested) { return; } // There is no nested flatbuffer.
const std::string unqualified_name = nested->constant;
std::string qualified_name = NestedFlatbufferType(unqualified_name);
if (qualified_name.empty()) { qualified_name = nested->constant; }
const ImportMapEntry import_entry = { qualified_name,
unqualified_name };
auto &code = *code_ptr;
GenReceiver(struct_def, code_ptr);
code += namer_.Method(field) + "NestedRoot(self)";
if (parser_.opts.python_typing) {
code += " -> Union[" + unqualified_name + ", int]";
imports.insert(ImportMapEntry{ "typing", "Union" });
imports.insert(import_entry);
}
code += ":";
code += OffsetPrefix(field);
if (!parser_.opts.python_typing) {
code += Indent + Indent + Indent;
code += "from " + import_entry.first + " import " + import_entry.second +
"\n";
}
code += Indent + Indent + Indent + "return " + unqualified_name;
code += ".GetRootAs";
code += "(self._tab.Bytes, self._tab.Vector(o))\n";
code += Indent + Indent + "return 0\n";
code += "\n";
}
// Begin the creator function signature.
void BeginBuilderArgs(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
code += "\n";
code += "def Create" + namer_.Type(struct_def);
code += "(builder";
}
// Recursively generate arguments for a constructor, to deal with nested
// structs.
void StructBuilderArgs(const StructDef &struct_def,
const std::string nameprefix,
const std::string namesuffix, bool has_field_name,
const std::string fieldname_suffix,
std::string *code_ptr) const {
for (auto it = struct_def.fields.vec.begin();
it != struct_def.fields.vec.end(); ++it) {
auto &field = **it;
const auto &field_type = field.value.type;
const auto &type =
IsArray(field_type) ? field_type.VectorType() : field_type;
if (IsStruct(type)) {
// Generate arguments for a struct inside a struct. To ensure names
// don't clash, and to make it obvious these arguments are constructing
// a nested struct, prefix the name with the field name.
auto subprefix = nameprefix;
if (has_field_name) {
subprefix += namer_.Field(field) + fieldname_suffix;
}
StructBuilderArgs(*field.value.type.struct_def, subprefix, namesuffix,
has_field_name, fieldname_suffix, code_ptr);
} else {
auto &code = *code_ptr;
code += std::string(", ") + nameprefix;
if (has_field_name) { code += namer_.Field(field); }
code += namesuffix;
}
}
}
// End the creator function signature.
void EndBuilderArgs(std::string *code_ptr) const {
auto &code = *code_ptr;
code += "):\n";
}
// Recursively generate struct construction statements and instert manual
// padding.
void StructBuilderBody(const StructDef &struct_def, const char *nameprefix,
std::string *code_ptr, size_t index = 0,
bool in_array = false) const {
auto &code = *code_ptr;
std::string indent(index * 4, ' ');
code +=
indent + " builder.Prep(" + NumToString(struct_def.minalign) + ", ";
code += NumToString(struct_def.bytesize) + ")\n";
for (auto it = struct_def.fields.vec.rbegin();
it != struct_def.fields.vec.rend(); ++it) {
auto &field = **it;
const auto &field_type = field.value.type;
const auto &type =
IsArray(field_type) ? field_type.VectorType() : field_type;
if (field.padding)
code +=
indent + " builder.Pad(" + NumToString(field.padding) + ")\n";
if (IsStruct(field_type)) {
StructBuilderBody(*field_type.struct_def,
(nameprefix + (namer_.Field(field) + "_")).c_str(),
code_ptr, index, in_array);
} else {
const auto index_var = "_idx" + NumToString(index);
if (IsArray(field_type)) {
code += indent + " for " + index_var + " in range(";
code += NumToString(field_type.fixed_length);
code += " , 0, -1):\n";
in_array = true;
}
if (IsStruct(type)) {
StructBuilderBody(*field_type.struct_def,
(nameprefix + (namer_.Field(field) + "_")).c_str(),
code_ptr, index + 1, in_array);
} else {
code += IsArray(field_type) ? " " : "";
code += indent + " builder.Prepend" + GenMethod(field) + "(";
code += nameprefix + namer_.Variable(field);
size_t array_cnt = index + (IsArray(field_type) ? 1 : 0);
for (size_t i = 0; in_array && i < array_cnt; i++) {
code += "[_idx" + NumToString(i) + "-1]";
}
code += ")\n";
}
}
}
}
void EndBuilderBody(std::string *code_ptr) const {
auto &code = *code_ptr;
code += " return builder.Offset()\n";
}
// Get the value of a table's starting offset.
void GetStartOfTable(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto struct_type = namer_.Type(struct_def);
// Generate method with struct name.
const auto name = parser_.opts.python_no_type_prefix_suffix
? "Start"
: struct_type + "Start";
code += "def " + name;
if (parser_.opts.python_typing) {
code += "(builder: flatbuffers.Builder):\n";
} else {
code += "(builder):\n";
}
code += Indent + "builder.StartObject(";
code += NumToString(struct_def.fields.vec.size());
code += ")\n\n";
if (!parser_.opts.one_file && !parser_.opts.python_no_type_prefix_suffix) {
// Generate method without struct name.
if (parser_.opts.python_typing) {
code += "def Start(builder: flatbuffers.Builder):\n";
} else {
code += "def Start(builder):\n";
}
code += Indent + struct_type + "Start(builder)\n\n";
}
}
// Set the value of a table's field.
void BuildFieldOfTable(const StructDef &struct_def, const FieldDef &field,
const size_t offset, std::string *code_ptr) const {
auto &code = *code_ptr;
const std::string field_var = namer_.Variable(field);
const std::string field_method = namer_.Method(field);
const std::string field_ty = GenFieldTy(field);
const auto name = parser_.opts.python_no_type_prefix_suffix
? "Add" + field_method
: namer_.Type(struct_def) + "Add" + field_method;
// Generate method with struct name.
code += "def " + name;
if (parser_.opts.python_typing) {
code += "(builder: flatbuffers.Builder, " + field_var + ": " + field_ty;
} else {
code += "(builder, " + field_var;
}
code += "):\n";
code += Indent + "builder.Prepend";
code += GenMethod(field) + "Slot(";
code += NumToString(offset) + ", ";
if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
code += "flatbuffers.number_types.UOffsetTFlags.py_type";
code += "(" + field_var + ")";
} else {
code += field_var;
}
code += ", ";
if (field.IsScalarOptional()) {
code += "None";
} else if (IsFloat(field.value.type.base_type)) {
code += float_const_gen_.GenFloatConstant(field);
} else {
code += field.value.constant;
}
code += ")\n\n";
if (!parser_.opts.one_file && !parser_.opts.python_no_type_prefix_suffix) {
// Generate method without struct name.
code += "def Add" + field_method;
if (parser_.opts.python_typing) {
code += "(builder: flatbuffers.Builder, " + field_var + ": " + field_ty;
} else {
code += "(builder, " + field_var;
}
code += "):\n";
code += Indent + namer_.Type(struct_def) + "Add" + field_method;
code += "(builder, ";
code += field_var;
code += ")\n\n";
}
}
// Set the value of one of the members of a table's vector.
void BuildVectorOfTable(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
const std::string struct_type = namer_.Type(struct_def);
const std::string field_method = namer_.Method(field);
// Generate method with struct name.
const auto name = parser_.opts.python_no_type_prefix_suffix
? "Start" + field_method
: struct_type + "Start" + field_method;
code += "def " + name;
if (parser_.opts.python_typing) {
code += "Vector(builder, numElems: int) -> int:\n";
} else {
code += "Vector(builder, numElems):\n";
}
code += Indent + "return builder.StartVector(";
auto vector_type = field.value.type.VectorType();
auto alignment = InlineAlignment(vector_type);
auto elem_size = InlineSize(vector_type);
code += NumToString(elem_size);
code += ", numElems, " + NumToString(alignment);
code += ")\n\n";
if (!parser_.opts.one_file && !parser_.opts.python_no_type_prefix_suffix) {
// Generate method without struct name.
code += "def Start" + field_method +
"Vector(builder, numElems: int) -> int:\n";
code += Indent + "return " + struct_type + "Start";
code += field_method + "Vector(builder, numElems)\n\n";
}
}
// Set the value of one of the members of a table's vector and fills in the
// elements from a bytearray. This is for simplifying the use of nested
// flatbuffers.
void BuildVectorOfTableFromBytes(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto nested = field.attributes.Lookup("nested_flatbuffer");
if (!nested) { return; } // There is no nested flatbuffer.
auto &code = *code_ptr;
const std::string field_method = namer_.Method(field);
const std::string struct_type = namer_.Type(struct_def);
// Generate method with struct and field name.
code += "def " + struct_type + "Make" + field_method;
code += "VectorFromBytes(builder, bytes):\n";
code += Indent + "builder.StartVector(";
auto vector_type = field.value.type.VectorType();
auto alignment = InlineAlignment(vector_type);
auto elem_size = InlineSize(vector_type);
code += NumToString(elem_size);
code += ", len(bytes), " + NumToString(alignment);
code += ")\n";
code += Indent + "builder.head = builder.head - len(bytes)\n";
code += Indent + "builder.Bytes[builder.head : builder.head + len(bytes)]";
code += " = bytes\n";
code += Indent + "return builder.EndVector()\n";
if (!parser_.opts.one_file) {
// Generate method without struct and field name.
code += "def Make" + field_method + "VectorFromBytes(builder, bytes):\n";
code += Indent + "return " + struct_type + "Make" + field_method +
"VectorFromBytes(builder, bytes)\n";
}
}
// Get the offset of the end of a table.
void GetEndOffsetOnTable(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto name = parser_.opts.python_no_type_prefix_suffix
? "End"
: namer_.Type(struct_def) + "End";
// Generate method with struct name.
if (parser_.opts.python_typing) {
code += "def " + name + "(builder: flatbuffers.Builder) -> int:\n";
} else {
code += "def " + name + "(builder):\n";
}
code += Indent + "return builder.EndObject()\n\n";
if (!parser_.opts.one_file && !parser_.opts.python_no_type_prefix_suffix) {
// Generate method without struct name.
if (parser_.opts.python_typing) {
code += "def End(builder: flatbuffers.Builder) -> int:\n";
} else {
code += "def End(builder):\n";
}
code += Indent + "return " + namer_.Type(struct_def) + "End(builder)";
code += "\n";
}
}
// Generate the receiver for function signatures.
void GenReceiver(const StructDef &struct_def, std::string *code_ptr) const {
auto &code = *code_ptr;
code += Indent + "# " + namer_.Type(struct_def) + "\n";
code += Indent + "def ";
}
// Generate a struct field, conditioned on its child type(s).
void GenStructAccessor(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr, ImportMap &imports) const {
GenComment(field.doc_comment, code_ptr, &def_comment, Indent.c_str());
if (IsScalar(field.value.type.base_type)) {
if (struct_def.fixed) {
GetScalarFieldOfStruct(struct_def, field, code_ptr);
} else {
GetScalarFieldOfTable(struct_def, field, code_ptr);
}
} else {
switch (field.value.type.base_type) {
case BASE_TYPE_STRUCT:
if (struct_def.fixed) {
GetStructFieldOfStruct(struct_def, field, code_ptr);
} else {
GetStructFieldOfTable(struct_def, field, code_ptr, imports);
}
break;
case BASE_TYPE_STRING:
GetStringField(struct_def, field, code_ptr, imports);
break;
case BASE_TYPE_VECTOR: {
auto vectortype = field.value.type.VectorType();
if (vectortype.base_type == BASE_TYPE_STRUCT) {
GetMemberOfVectorOfStruct(struct_def, field, code_ptr, imports);
} else {
GetMemberOfVectorOfNonStruct(struct_def, field, code_ptr);
GetVectorOfNonStructAsNumpy(struct_def, field, code_ptr);
GetVectorAsNestedFlatbuffer(struct_def, field, code_ptr, imports);
}
break;
}
case BASE_TYPE_ARRAY: {
auto vectortype = field.value.type.VectorType();
if (vectortype.base_type == BASE_TYPE_STRUCT) {
GetArrayOfStruct(struct_def, field, code_ptr, imports);
} else {
GetArrayOfNonStruct(struct_def, field, code_ptr);
GetVectorOfNonStructAsNumpy(struct_def, field, code_ptr);
GetVectorAsNestedFlatbuffer(struct_def, field, code_ptr, imports);
}
break;
}
case BASE_TYPE_UNION:
GetUnionField(struct_def, field, code_ptr, imports);
break;
default: FLATBUFFERS_ASSERT(0);
}
}
if (IsVector(field.value.type) || IsArray(field.value.type)) {
GetVectorLen(struct_def, field, code_ptr);
GetVectorIsNone(struct_def, field, code_ptr);
}
}
// Generate struct sizeof.
void GenStructSizeOf(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
code += Indent + "@classmethod\n";
if (parser_.opts.python_typing) {
code += Indent + "def SizeOf(cls) -> int:\n";
} else {
code += Indent + "def SizeOf(cls):\n";
}
code +=
Indent + Indent + "return " + NumToString(struct_def.bytesize) + "\n";
code += "\n";
}
// Generate table constructors, conditioned on its members' types.
void GenTableBuilders(const StructDef &struct_def,
std::string *code_ptr) const {
GetStartOfTable(struct_def, code_ptr);
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();
BuildFieldOfTable(struct_def, field, offset, code_ptr);
if (IsVector(field.value.type)) {
BuildVectorOfTable(struct_def, field, code_ptr);
BuildVectorOfTableFromBytes(struct_def, field, code_ptr);
}
}
GetEndOffsetOnTable(struct_def, code_ptr);
}
// Generate function to check for proper file identifier
void GenHasFileIdentifier(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
std::string escapedID;
// In the event any of file_identifier characters are special(NULL, \, etc),
// problems occur. To prevent this, convert all chars to their hex-escaped
// equivalent.
for (auto it = parser_.file_identifier_.begin();
it != parser_.file_identifier_.end(); ++it) {
escapedID += "\\x" + IntToStringHex(*it, 2);
}
code += Indent + "@classmethod\n";
code += Indent + "def " + namer_.Type(struct_def);
code += "BufferHasIdentifier(cls, buf, offset, size_prefixed=False):";
code += "\n";
code += Indent + Indent;
code += "return flatbuffers.util.BufferHasIdentifier(buf, offset, b\"";
code += escapedID;
code += "\", size_prefixed=size_prefixed)\n";
code += "\n";
}
// Generates struct or table methods.
void GenStruct(const StructDef &struct_def, std::string *code_ptr,
ImportMap &imports) const {
if (struct_def.generated) return;
GenComment(struct_def.doc_comment, code_ptr, &def_comment);
BeginClass(struct_def, code_ptr);
if (!struct_def.fixed) {
// Generate a special accessor for the table that has been declared as
// the root type.
NewRootTypeFromBuffer(struct_def, code_ptr);
if (parser_.file_identifier_.length()) {
// Generate a special function to test file_identifier
GenHasFileIdentifier(struct_def, code_ptr);
}
} else {
// Generates the SizeOf method for all structs.
GenStructSizeOf(struct_def, code_ptr);
}
// Generates the Init method that sets the field in a pre-existing
// accessor object. This is to allow object reuse.
InitializeExisting(struct_def, code_ptr);
for (auto it = struct_def.fields.vec.begin();
it != struct_def.fields.vec.end(); ++it) {
auto &field = **it;
if (field.deprecated) continue;
GenStructAccessor(struct_def, field, code_ptr, imports);
}
if (struct_def.fixed) {
// creates a struct constructor function
GenStructBuilder(struct_def, code_ptr);
} else {
// Creates a set of functions that allow table construction.
GenTableBuilders(struct_def, code_ptr);
}
}
void GenReceiverForObjectAPI(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
code += GenIndents(1) + "# " + namer_.ObjectType(struct_def);
code += GenIndents(1) + "def ";
}
void BeginClassForObjectAPI(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
code += "\n";
code += "class " + namer_.ObjectType(struct_def) + "(object):";
code += "\n";
}
// Gets the accoresponding python builtin type of a BaseType for scalars and
// string.
std::string GetBasePythonTypeForScalarAndString(
const BaseType &base_type) const {
if (IsBool(base_type)) {
return "bool";
} else if (IsFloat(base_type)) {
return "float";
} else if (IsInteger(base_type)) {
return "int";
} else if (base_type == BASE_TYPE_STRING) {
return "str";
} else {
FLATBUFFERS_ASSERT(false && "base_type is not a scalar or string type.");
return "";
}
}
std::string GetDefaultValue(const FieldDef &field) const {
BaseType base_type = field.value.type.base_type;
if (field.IsScalarOptional()) {
return "None";
} else if (IsBool(base_type)) {
return field.value.constant == "0" ? "False" : "True";
} else if (IsFloat(base_type)) {
return float_const_gen_.GenFloatConstant(field);
} else if (IsInteger(base_type)) {
return field.value.constant;
} else {
// For string, struct, and table.
return "None";
}
}
void GenUnionInit(const FieldDef &field, std::string *field_types_ptr,
std::set<std::string> *import_list,
std::set<std::string> *import_typing_list) const {
// Gets all possible types in the union.
import_typing_list->insert("Union");
auto &field_types = *field_types_ptr;
field_types = "Union[";
std::string separator_string = ", ";
auto enum_def = field.value.type.enum_def;
for (auto it = enum_def->Vals().begin(); it != enum_def->Vals().end();
++it) {
auto &ev = **it;
// Union only supports string and table.
std::string field_type;
switch (ev.union_type.base_type) {
case BASE_TYPE_STRUCT:
field_type = namer_.ObjectType(*ev.union_type.struct_def);
if (parser_.opts.include_dependence_headers) {
auto package_reference = GenPackageReference(ev.union_type);
field_type = package_reference + "." + field_type;
import_list->insert("import " + package_reference);
}
break;
case BASE_TYPE_STRING: field_type += "str"; break;
case BASE_TYPE_NONE: field_type += "None"; break;
default: break;
}
field_types += field_type + separator_string;
}
// Removes the last separator_string.
field_types.erase(field_types.length() - separator_string.size());
field_types += "]";
// Gets the import lists for the union.
if (parser_.opts.include_dependence_headers) {
const auto package_reference = GenPackageReference(field.value.type);
import_list->insert("import " + package_reference);
}
}
void GenStructInit(const FieldDef &field, std::string *out_ptr,
std::set<std::string> *import_list,
std::set<std::string> *import_typing_list) const {
import_typing_list->insert("Optional");
auto &output = *out_ptr;
const Type &type = field.value.type;
const std::string object_type = namer_.ObjectType(*type.struct_def);
if (parser_.opts.include_dependence_headers) {
auto package_reference = GenPackageReference(type);
output = package_reference + "." + object_type + "]";
import_list->insert("import " + package_reference);
} else {
output = object_type + "]";
}
output = "Optional[" + output;
}
void GenVectorInit(const FieldDef &field, std::string *field_type_ptr,
std::set<std::string> *import_list,
std::set<std::string> *import_typing_list) const {
import_typing_list->insert("List");
auto &field_type = *field_type_ptr;
const Type &vector_type = field.value.type.VectorType();
const BaseType base_type = vector_type.base_type;
if (base_type == BASE_TYPE_STRUCT) {
const std::string object_type =
namer_.ObjectType(*vector_type.struct_def);
field_type = object_type + "]";
if (parser_.opts.include_dependence_headers) {
auto package_reference = GenPackageReference(vector_type);
field_type = package_reference + "." + object_type + "]";
import_list->insert("import " + package_reference);
}
field_type = "List[" + field_type;
} else {
field_type =
"List[" + GetBasePythonTypeForScalarAndString(base_type) + "]";
}
}
void GenInitialize(const StructDef &struct_def, std::string *code_ptr,
std::set<std::string> *import_list) const {
std::string code;
std::set<std::string> import_typing_list;
for (auto it = struct_def.fields.vec.begin();
it != struct_def.fields.vec.end(); ++it) {
auto &field = **it;
if (field.deprecated) continue;
// Determines field type, default value, and typing imports.
auto base_type = field.value.type.base_type;
std::string field_type;
switch (base_type) {
case BASE_TYPE_UNION: {
GenUnionInit(field, &field_type, import_list, &import_typing_list);
break;
}
case BASE_TYPE_STRUCT: {
GenStructInit(field, &field_type, import_list, &import_typing_list);
break;
}
case BASE_TYPE_VECTOR:
case BASE_TYPE_ARRAY: {
GenVectorInit(field, &field_type, import_list, &import_typing_list);
break;
}
default:
// Scalar or sting fields.
field_type = GetBasePythonTypeForScalarAndString(base_type);
if (field.IsScalarOptional()) {
field_type = "Optional[" + field_type + "]";
}
break;
}
const auto default_value = GetDefaultValue(field);
// Wrties the init statement.
const auto field_field = namer_.Field(field);
code += GenIndents(2) + "self." + field_field + " = " + default_value +
" # type: " + field_type;
}
// Writes __init__ method.
auto &code_base = *code_ptr;
GenReceiverForObjectAPI(struct_def, code_ptr);
code_base += "__init__(self):";
if (code.empty()) {
code_base += GenIndents(2) + "pass";
} else {
code_base += code;
}
code_base += "\n";
// Merges the typing imports into import_list.
if (!import_typing_list.empty()) {
// Adds the try statement.
std::string typing_imports = "try:";
typing_imports += GenIndents(1) + "from typing import ";
std::string separator_string = ", ";
for (auto it = import_typing_list.begin(); it != import_typing_list.end();
++it) {
const std::string &im = *it;
typing_imports += im + separator_string;
}
// Removes the last separator_string.
typing_imports.erase(typing_imports.length() - separator_string.size());
// Adds the except statement.
typing_imports += "\n";
typing_imports += "except:";
typing_imports += GenIndents(1) + "pass";
import_list->insert(typing_imports);
}
// Removes the import of the struct itself, if applied.
auto struct_import = "import " + namer_.NamespacedType(struct_def);
import_list->erase(struct_import);
}
void InitializeFromBuf(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto struct_var = namer_.Variable(struct_def);
const auto struct_type = namer_.Type(struct_def);
code += GenIndents(1) + "@classmethod";
code += GenIndents(1) + "def InitFromBuf(cls, buf, pos):";
code += GenIndents(2) + struct_var + " = " + struct_type + "()";
code += GenIndents(2) + struct_var + ".Init(buf, pos)";
code += GenIndents(2) + "return cls.InitFromObj(" + struct_var + ")";
code += "\n";
}
void InitializeFromPackedBuf(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto struct_var = namer_.Variable(struct_def);
const auto struct_type = namer_.Type(struct_def);
code += GenIndents(1) + "@classmethod";
code += GenIndents(1) + "def InitFromPackedBuf(cls, buf, pos=0):";
code += GenIndents(2) +
"n = flatbuffers.encode.Get(flatbuffers.packer.uoffset, buf, pos)";
code += GenIndents(2) + "return cls.InitFromBuf(buf, pos+n)";
code += "\n";
}
void InitializeFromObjForObject(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto struct_var = namer_.Variable(struct_def);
const auto struct_object = namer_.ObjectType(struct_def);
code += GenIndents(1) + "@classmethod";
code += GenIndents(1) + "def InitFromObj(cls, " + struct_var + "):";
code += GenIndents(2) + "x = " + struct_object + "()";
code += GenIndents(2) + "x._UnPack(" + struct_var + ")";
code += GenIndents(2) + "return x";
code += "\n";
}
void GenCompareOperator(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
code += GenIndents(1) + "def __eq__(self, other):";
code += GenIndents(2) + "return type(self) == type(other)";
for (auto it = struct_def.fields.vec.begin();
it != struct_def.fields.vec.end(); ++it) {
auto &field = **it;
if (field.deprecated) continue;
// Wrties the comparison statement for this field.
const auto field_field = namer_.Field(field);
code += " and \\" + GenIndents(3) + "self." + field_field +
" == " + "other." + field_field;
}
code += "\n";
}
void GenUnPackForStruct(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto struct_var = namer_.Variable(struct_def);
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
auto field_type = TypeName(field);
if (parser_.opts.include_dependence_headers) {
auto package_reference = GenPackageReference(field.value.type);
field_type = package_reference + "." + TypeName(field);
}
code += GenIndents(2) + "if " + struct_var + "." + field_method + "(";
// if field is a struct, we need to create an instance for it first.
if (struct_def.fixed && field.value.type.base_type == BASE_TYPE_STRUCT) {
code += field_type + "()";
}
code += ") is not None:";
code += GenIndents(3) + "self." + field_field + " = " +
namer_.ObjectType(field_type) + +".InitFromObj(" + struct_var +
"." + field_method + "(";
// A struct's accessor requires a struct buf instance.
if (struct_def.fixed && field.value.type.base_type == BASE_TYPE_STRUCT) {
code += field_type + "()";
}
code += "))";
}
void GenUnPackForUnion(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_var = namer_.Variable(struct_def);
const EnumDef &enum_def = *field.value.type.enum_def;
auto union_type = namer_.Type(enum_def);
if (parser_.opts.include_dependence_headers) {
union_type = namer_.NamespacedType(enum_def) + "." + union_type;
}
code += GenIndents(2) + "self." + field_field + " = " + union_type +
"Creator(" + "self." + field_field + "Type, " + struct_var + "." +
field_method + "())";
}
void GenUnPackForStructVector(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_var = namer_.Variable(struct_def);
code += GenIndents(2) + "if not " + struct_var + "." + field_method +
"IsNone():";
code += GenIndents(3) + "self." + field_field + " = []";
code += GenIndents(3) + "for i in range(" + struct_var + "." +
field_method + "Length()):";
auto field_type = TypeName(field);
auto one_instance = field_type + "_";
one_instance[0] = CharToLower(one_instance[0]);
if (parser_.opts.include_dependence_headers) {
auto package_reference = GenPackageReference(field.value.type);
field_type = package_reference + "." + TypeName(field);
}
code += GenIndents(4) + "if " + struct_var + "." + field_method +
"(i) is None:";
code += GenIndents(5) + "self." + field_field + ".append(None)";
code += GenIndents(4) + "else:";
code += GenIndents(5) + one_instance + " = " +
namer_.ObjectType(field_type) + ".InitFromObj(" + struct_var + "." +
field_method + "(i))";
code +=
GenIndents(5) + "self." + field_field + ".append(" + one_instance + ")";
}
void GenUnpackForTableVector(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_var = namer_.Variable(struct_def);
code += GenIndents(2) + "if not " + struct_var + "." + field_method +
"IsNone():";
code += GenIndents(3) + "self." + field_field + " = []";
code += GenIndents(3) + "for i in range(" + struct_var + "." +
field_method + "Length()):";
auto field_type = TypeName(field);
auto one_instance = field_type + "_";
one_instance[0] = CharToLower(one_instance[0]);
if (parser_.opts.include_dependence_headers) {
auto package_reference = GenPackageReference(field.value.type);
field_type = package_reference + "." + TypeName(field);
}
code += GenIndents(4) + "if " + struct_var + "." + field_method +
"(i) is None:";
code += GenIndents(5) + "self." + field_field + ".append(None)";
code += GenIndents(4) + "else:";
code += GenIndents(5) + one_instance + " = " +
namer_.ObjectType(field_type) + ".InitFromObj(" + struct_var + "." +
field_method + "(i))";
code +=
GenIndents(5) + "self." + field_field + ".append(" + one_instance + ")";
}
void GenUnpackforScalarVectorHelper(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr,
int indents) const {
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_var = namer_.Variable(struct_def);
code += GenIndents(indents) + "self." + field_field + " = []";
code += GenIndents(indents) + "for i in range(" + struct_var + "." +
field_method + "Length()):";
code += GenIndents(indents + 1) + "self." + field_field + ".append(" +
struct_var + "." + field_method + "(i))";
}
void GenUnPackForScalarVector(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_var = namer_.Variable(struct_def);
code += GenIndents(2) + "if not " + struct_var + "." + field_method +
"IsNone():";
// String does not have the AsNumpy method.
if (!(IsScalar(field.value.type.VectorType().base_type))) {
GenUnpackforScalarVectorHelper(struct_def, field, code_ptr, 3);
return;
}
code += GenIndents(3) + "if np is None:";
GenUnpackforScalarVectorHelper(struct_def, field, code_ptr, 4);
// If numpy exists, use the AsNumpy method to optimize the unpack speed.
code += GenIndents(3) + "else:";
code += GenIndents(4) + "self." + field_field + " = " + struct_var + "." +
field_method + "AsNumpy()";
}
void GenUnPackForScalar(const StructDef &struct_def, const FieldDef &field,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_var = namer_.Variable(struct_def);
code += GenIndents(2) + "self." + field_field + " = " + struct_var + "." +
field_method + "()";
}
// Generates the UnPack method for the object class.
void GenUnPack(const StructDef &struct_def, std::string *code_ptr) const {
std::string code;
// Items that needs to be imported. No duplicate modules will be imported.
std::set<std::string> import_list;
for (auto it = struct_def.fields.vec.begin();
it != struct_def.fields.vec.end(); ++it) {
auto &field = **it;
if (field.deprecated) continue;
auto field_type = TypeName(field);
switch (field.value.type.base_type) {
case BASE_TYPE_STRUCT: {
GenUnPackForStruct(struct_def, field, &code);
break;
}
case BASE_TYPE_UNION: {
GenUnPackForUnion(struct_def, field, &code);
break;
}
case BASE_TYPE_ARRAY:
case BASE_TYPE_VECTOR: {
auto vectortype = field.value.type.VectorType();
if (vectortype.base_type == BASE_TYPE_STRUCT) {
GenUnPackForStructVector(struct_def, field, &code);
} else {
GenUnPackForScalarVector(struct_def, field, &code);
}
break;
}
default: GenUnPackForScalar(struct_def, field, &code);
}
}
// Writes import statements and code into the generated file.
auto &code_base = *code_ptr;
const auto struct_var = namer_.Variable(struct_def);
GenReceiverForObjectAPI(struct_def, code_ptr);
code_base += "_UnPack(self, " + struct_var + "):";
code_base += GenIndents(2) + "if " + struct_var + " is None:";
code_base += GenIndents(3) + "return";
// Write the import statements.
for (std::set<std::string>::iterator it = import_list.begin();
it != import_list.end(); ++it) {
code_base += GenIndents(2) + *it;
}
// Write the code.
code_base += code;
code_base += "\n";
}
void GenPackForStruct(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto struct_fn = namer_.Function(struct_def);
GenReceiverForObjectAPI(struct_def, code_ptr);
code += "Pack(self, builder):";
code += GenIndents(2) + "return Create" + struct_fn + "(builder";
StructBuilderArgs(struct_def,
/* nameprefix = */ "self.",
/* namesuffix = */ "",
/* has_field_name = */ true,
/* fieldname_suffix = */ ".", code_ptr);
code += ")\n";
}
void GenPackForStructVectorField(const StructDef &struct_def,
const FieldDef &field,
std::string *code_prefix_ptr,
std::string *code_ptr) const {
auto &code_prefix = *code_prefix_ptr;
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto struct_type = namer_.Type(struct_def);
const auto field_method = namer_.Method(field);
// Creates the field.
code_prefix += GenIndents(2) + "if self." + field_field + " is not None:";
if (field.value.type.struct_def->fixed) {
code_prefix += GenIndents(3) + struct_type + "Start" + field_method +
"Vector(builder, len(self." + field_field + "))";
code_prefix += GenIndents(3) + "for i in reversed(range(len(self." +
field_field + "))):";
code_prefix +=
GenIndents(4) + "self." + field_field + "[i].Pack(builder)";
code_prefix += GenIndents(3) + field_field + " = builder.EndVector()";
} else {
// If the vector is a struct vector, we need to first build accessor for
// each struct element.
code_prefix += GenIndents(3) + field_field + "list = []";
code_prefix += GenIndents(3);
code_prefix += "for i in range(len(self." + field_field + ")):";
code_prefix += GenIndents(4) + field_field + "list.append(self." +
field_field + "[i].Pack(builder))";
code_prefix += GenIndents(3) + struct_type + "Start" + field_method +
"Vector(builder, len(self." + field_field + "))";
code_prefix += GenIndents(3) + "for i in reversed(range(len(self." +
field_field + "))):";
code_prefix += GenIndents(4) + "builder.PrependUOffsetTRelative" + "(" +
field_field + "list[i])";
code_prefix += GenIndents(3) + field_field + " = builder.EndVector()";
}
// Adds the field into the struct.
code += GenIndents(2) + "if self." + field_field + " is not None:";
code += GenIndents(3) + struct_type + "Add" + field_method + "(builder, " +
field_field + ")";
}
void GenPackForScalarVectorFieldHelper(const StructDef &struct_def,
const FieldDef &field,
std::string *code_ptr,
int indents) const {
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_type = namer_.Type(struct_def);
const auto vectortype = field.value.type.VectorType();
code += GenIndents(indents) + struct_type + "Start" + field_method +
"Vector(builder, len(self." + field_field + "))";
code += GenIndents(indents) + "for i in reversed(range(len(self." +
field_field + "))):";
code += GenIndents(indents + 1) + "builder.Prepend";
std::string type_name;
switch (vectortype.base_type) {
case BASE_TYPE_BOOL: type_name = "Bool"; break;
case BASE_TYPE_CHAR: type_name = "Byte"; break;
case BASE_TYPE_UCHAR: type_name = "Uint8"; break;
case BASE_TYPE_SHORT: type_name = "Int16"; break;
case BASE_TYPE_USHORT: type_name = "Uint16"; break;
case BASE_TYPE_INT: type_name = "Int32"; break;
case BASE_TYPE_UINT: type_name = "Uint32"; break;
case BASE_TYPE_LONG: type_name = "Int64"; break;
case BASE_TYPE_ULONG: type_name = "Uint64"; break;
case BASE_TYPE_FLOAT: type_name = "Float32"; break;
case BASE_TYPE_DOUBLE: type_name = "Float64"; break;
case BASE_TYPE_STRING: type_name = "UOffsetTRelative"; break;
default: type_name = "VOffsetT"; break;
}
code += type_name;
}
void GenPackForScalarVectorField(const StructDef &struct_def,
const FieldDef &field,
std::string *code_prefix_ptr,
std::string *code_ptr) const {
auto &code = *code_ptr;
auto &code_prefix = *code_prefix_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_type = namer_.Type(struct_def);
// Adds the field into the struct.
code += GenIndents(2) + "if self." + field_field + " is not None:";
code += GenIndents(3) + struct_type + "Add" + field_method + "(builder, " +
field_field + ")";
// Creates the field.
code_prefix += GenIndents(2) + "if self." + field_field + " is not None:";
// If the vector is a string vector, we need to first build accessor for
// each string element. And this generated code, needs to be
// placed ahead of code_prefix.
auto vectortype = field.value.type.VectorType();
if (IsString(vectortype)) {
code_prefix += GenIndents(3) + field_field + "list = []";
code_prefix +=
GenIndents(3) + "for i in range(len(self." + field_field + ")):";
code_prefix += GenIndents(4) + field_field +
"list.append(builder.CreateString(self." + field_field +
"[i]))";
GenPackForScalarVectorFieldHelper(struct_def, field, code_prefix_ptr, 3);
code_prefix += "(" + field_field + "list[i])";
code_prefix += GenIndents(3) + field_field + " = builder.EndVector()";
return;
}
code_prefix += GenIndents(3) + "if np is not None and type(self." +
field_field + ") is np.ndarray:";
code_prefix += GenIndents(4) + field_field +
" = builder.CreateNumpyVector(self." + field_field + ")";
code_prefix += GenIndents(3) + "else:";
GenPackForScalarVectorFieldHelper(struct_def, field, code_prefix_ptr, 4);
code_prefix += "(self." + field_field + "[i])";
code_prefix += GenIndents(4) + field_field + " = builder.EndVector()";
}
void GenPackForStructField(const StructDef &struct_def, const FieldDef &field,
std::string *code_prefix_ptr,
std::string *code_ptr) const {
auto &code_prefix = *code_prefix_ptr;
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_type = namer_.Type(struct_def);
if (field.value.type.struct_def->fixed) {
// Pure struct fields need to be created along with their parent
// structs.
code += GenIndents(2) + "if self." + field_field + " is not None:";
code += GenIndents(3) + field_field + " = self." + field_field +
".Pack(builder)";
} else {
// Tables need to be created before their parent structs are created.
code_prefix += GenIndents(2) + "if self." + field_field + " is not None:";
code_prefix += GenIndents(3) + field_field + " = self." + field_field +
".Pack(builder)";
code += GenIndents(2) + "if self." + field_field + " is not None:";
}
code += GenIndents(3) + struct_type + "Add" + field_method + "(builder, " +
field_field + ")";
}
void GenPackForUnionField(const StructDef &struct_def, const FieldDef &field,
std::string *code_prefix_ptr,
std::string *code_ptr) const {
auto &code_prefix = *code_prefix_ptr;
auto &code = *code_ptr;
const auto field_field = namer_.Field(field);
const auto field_method = namer_.Method(field);
const auto struct_type = namer_.Type(struct_def);
// TODO(luwa): TypeT should be moved under the None check as well.
code_prefix += GenIndents(2) + "if self." + field_field + " is not None:";
code_prefix += GenIndents(3) + field_field + " = self." + field_field +
".Pack(builder)";
code += GenIndents(2) + "if self." + field_field + " is not None:";
code += GenIndents(3) + struct_type + "Add" + field_method + "(builder, " +
field_field + ")";
}
void GenPackForTable(const StructDef &struct_def,
std::string *code_ptr) const {
auto &code_base = *code_ptr;
std::string code, code_prefix;
const auto struct_var = namer_.Variable(struct_def);
const auto struct_type = namer_.Type(struct_def);
GenReceiverForObjectAPI(struct_def, code_ptr);
code_base += "Pack(self, builder):";
code += GenIndents(2) + struct_type + "Start(builder)";
for (auto it = struct_def.fields.vec.begin();
it != struct_def.fields.vec.end(); ++it) {
auto &field = **it;
if (field.deprecated) continue;
const auto field_method = namer_.Method(field);
const auto field_field = namer_.Field(field);
switch (field.value.type.base_type) {
case BASE_TYPE_STRUCT: {
GenPackForStructField(struct_def, field, &code_prefix, &code);
break;
}
case BASE_TYPE_UNION: {
GenPackForUnionField(struct_def, field, &code_prefix, &code);
break;
}
case BASE_TYPE_ARRAY:
case BASE_TYPE_VECTOR: {
auto vectortype = field.value.type.VectorType();
if (vectortype.base_type == BASE_TYPE_STRUCT) {
GenPackForStructVectorField(struct_def, field, &code_prefix, &code);
} else {
GenPackForScalarVectorField(struct_def, field, &code_prefix, &code);
}
break;
}
case BASE_TYPE_STRING: {
code_prefix +=
GenIndents(2) + "if self." + field_field + " is not None:";
code_prefix += GenIndents(3) + field_field +
" = builder.CreateString(self." + field_field + ")";
code += GenIndents(2) + "if self." + field_field + " is not None:";
code += GenIndents(3) + struct_type + "Add" + field_method +
"(builder, " + field_field + ")";
break;
}
default:
// Generates code for scalar values. If the value equals to the
// default value, builder will automatically ignore it. So we don't
// need to check the value ahead.
code += GenIndents(2) + struct_type + "Add" + field_method +
"(builder, self." + field_field + ")";
break;
}
}
code += GenIndents(2) + struct_var + " = " + struct_type + "End(builder)";
code += GenIndents(2) + "return " + struct_var;
code_base += code_prefix + code;
code_base += "\n";
}
void GenStructForObjectAPI(const StructDef &struct_def,
std::string *code_ptr) const {
if (struct_def.generated) return;
std::set<std::string> import_list;
std::string code;
// Creates an object class for a struct or a table
BeginClassForObjectAPI(struct_def, &code);
GenInitialize(struct_def, &code, &import_list);
InitializeFromBuf(struct_def, &code);
InitializeFromPackedBuf(struct_def, &code);
InitializeFromObjForObject(struct_def, &code);
if (parser_.opts.gen_compare) { GenCompareOperator(struct_def, &code); }
GenUnPack(struct_def, &code);
if (struct_def.fixed) {
GenPackForStruct(struct_def, &code);
} else {
GenPackForTable(struct_def, &code);
}
// Adds the imports at top.
auto &code_base = *code_ptr;
code_base += "\n";
for (auto it = import_list.begin(); it != import_list.end(); it++) {
auto im = *it;
code_base += im + "\n";
}
code_base += code;
}
void GenUnionCreatorForStruct(const EnumDef &enum_def, const EnumVal &ev,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto union_type = namer_.Type(enum_def);
const auto variant = namer_.Variant(ev);
auto field_type = namer_.ObjectType(*ev.union_type.struct_def);
code +=
GenIndents(1) + "if unionType == " + union_type + "()." + variant + ":";
if (parser_.opts.include_dependence_headers) {
auto package_reference = GenPackageReference(ev.union_type);
code += GenIndents(2) + "import " + package_reference;
field_type = package_reference + "." + field_type;
}
code += GenIndents(2) + "return " + field_type +
".InitFromBuf(table.Bytes, table.Pos)";
}
void GenUnionCreatorForString(const EnumDef &enum_def, const EnumVal &ev,
std::string *code_ptr) const {
auto &code = *code_ptr;
const auto union_type = namer_.Type(enum_def);
const auto variant = namer_.Variant(ev);
code +=
GenIndents(1) + "if unionType == " + union_type + "()." + variant + ":";
code += GenIndents(2) + "tab = Table(table.Bytes, table.Pos)";
code += GenIndents(2) + "union = tab.String(table.Pos)";
code += GenIndents(2) + "return union";
}
// Creates an union object based on union type.
void GenUnionCreator(const EnumDef &enum_def, std::string *code_ptr) const {
if (enum_def.generated) return;
auto &code = *code_ptr;
const auto enum_fn = namer_.Function(enum_def);
code += "\n";
code += "def " + enum_fn + "Creator(unionType, table):";
code += GenIndents(1) + "from flatbuffers.table import Table";
code += GenIndents(1) + "if not isinstance(table, Table):";
code += GenIndents(2) + "return None";
for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
auto &ev = **it;
// Union only supports string and table.
switch (ev.union_type.base_type) {
case BASE_TYPE_STRUCT:
GenUnionCreatorForStruct(enum_def, ev, &code);
break;
case BASE_TYPE_STRING:
GenUnionCreatorForString(enum_def, ev, &code);
break;
default: break;
}
}
code += GenIndents(1) + "return None";
code += "\n";
}
// Generate enum declarations.
void GenEnum(const EnumDef &enum_def, std::string *code_ptr) const {
if (enum_def.generated) return;
GenComment(enum_def.doc_comment, code_ptr, &def_comment);
BeginEnum(enum_def, code_ptr);
for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
auto &ev = **it;
GenComment(ev.doc_comment, code_ptr, &def_comment, Indent.c_str());
EnumMember(enum_def, ev, code_ptr);
}
}
// Returns the function name that is able to read a value of the given type.
std::string GenGetter(const Type &type) const {
switch (type.base_type) {
case BASE_TYPE_STRING: return "self._tab.String(";
case BASE_TYPE_UNION: return "self._tab.Union(";
case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());
default:
return "self._tab.Get(flatbuffers.number_types." +
namer_.Method(GenTypeGet(type)) + "Flags, ";
}
}
std::string GenFieldTy(const FieldDef &field) const {
if (IsScalar(field.value.type.base_type) || IsArray(field.value.type)) {
const std::string ty = GenTypeBasic(field.value.type);
if (ty.find("int") != std::string::npos) { return "int"; }
if (ty.find("float") != std::string::npos) { return "float"; }
if (ty == "bool") { return "bool"; }
return "Any";
} else {
if (IsStruct(field.value.type)) {
return "Any";
} else {
return "int";
}
}
}
// Returns the method name for use with add/put calls.
std::string GenMethod(const FieldDef &field) const {
return (IsScalar(field.value.type.base_type) || IsArray(field.value.type))
? namer_.Method(GenTypeBasic(field.value.type))
: (IsStruct(field.value.type) ? "Struct" : "UOffsetTRelative");
}
std::string GenTypeBasic(const Type &type) const {
// clang-format off
static const char *ctypename[] = {
#define FLATBUFFERS_TD(ENUM, IDLTYPE, \
CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, ...) \
#PTYPE,
FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
#undef FLATBUFFERS_TD
};
// clang-format on
return ctypename[IsArray(type) ? type.VectorType().base_type
: type.base_type];
}
std::string GenTypePointer(const Type &type) const {
switch (type.base_type) {
case BASE_TYPE_STRING: return "string";
case BASE_TYPE_VECTOR:
// fall through
case BASE_TYPE_ARRAY: return GenTypeGet(type.VectorType());
case BASE_TYPE_STRUCT: return type.struct_def->name;
case BASE_TYPE_UNION:
// fall through
default: return "*flatbuffers.Table";
}
}
std::string GenTypeGet(const Type &type) const {
return IsScalar(type.base_type) ? GenTypeBasic(type) : GenTypePointer(type);
}
std::string TypeName(const FieldDef &field) const {
return GenTypeGet(field.value.type);
}
std::string ReturnType(const StructDef &struct_def,
const FieldDef &field) const {
// If we have a class member that returns an instance of the same class,
// for example:
// class Field(object):
// def Children(self, j: int) -> Optional[Field]:
// pass
//
// we need to quote the return type:
// class Field(object):
// def Children(self, j: int) -> Optional['Field']:
// pass
//
// because Python is unable to resolve the name during parse and will return
// an error.
// (see PEP 484 under forward references:
// https://peps.python.org/pep-0484/#forward-references)
const std::string self_type = struct_def.name;
std::string field_type = TypeName(field);
if (self_type == field_type) { field_type = "'" + field_type + "'"; }
return field_type;
}
// Create a struct with a builder and the struct's arguments.
void GenStructBuilder(const StructDef &struct_def,
std::string *code_ptr) const {
BeginBuilderArgs(struct_def, code_ptr);
StructBuilderArgs(struct_def,
/* nameprefix = */ "",
/* namesuffix = */ "",
/* has_field_name = */ true,
/* fieldname_suffix = */ "_", code_ptr);
EndBuilderArgs(code_ptr);
StructBuilderBody(struct_def, "", code_ptr);
EndBuilderBody(code_ptr);
}
bool generate() {
std::string one_file_code;
ImportMap one_file_imports;
if (!generateEnums(&one_file_code)) return false;
if (!generateStructs(&one_file_code, one_file_imports)) return false;
if (parser_.opts.one_file) {
const std::string mod = file_name_ + "_generated";
// Legacy file format uses keep casing.
return SaveType(mod + ".py", *parser_.current_namespace_, one_file_code,
one_file_imports, mod, true);
}
return true;
}
private:
bool generateEnums(std::string *one_file_code) const {
for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
++it) {
auto &enum_def = **it;
std::string enumcode;
GenEnum(enum_def, &enumcode);
if (parser_.opts.generate_object_based_api & enum_def.is_union) {
GenUnionCreator(enum_def, &enumcode);
}
if (parser_.opts.one_file && !enumcode.empty()) {
*one_file_code += enumcode + "\n\n";
} else {
ImportMap imports;
const std::string mod =
namer_.File(enum_def, SkipFile::SuffixAndExtension);
if (!SaveType(namer_.File(enum_def, SkipFile::Suffix),
*enum_def.defined_namespace, enumcode, imports, mod,
false))
return false;
}
}
return true;
}
bool generateStructs(std::string *one_file_code,
ImportMap &one_file_imports) const {
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
auto &struct_def = **it;
std::string declcode;
ImportMap imports;
GenStruct(struct_def, &declcode, imports);
if (parser_.opts.generate_object_based_api) {
GenStructForObjectAPI(struct_def, &declcode);
}
if (parser_.opts.one_file) {
if (!declcode.empty()) { *one_file_code += declcode + "\n\n"; }
for (auto import_str : imports) { one_file_imports.insert(import_str); }
} else {
const std::string mod =
namer_.File(struct_def, SkipFile::SuffixAndExtension);
if (!SaveType(namer_.File(struct_def, SkipFile::Suffix),
*struct_def.defined_namespace, declcode, imports, mod,
true))
return false;
}
}
return true;
}
// Begin by declaring namespace and imports.
void BeginFile(const std::string &name_space_name, const bool needs_imports,
std::string *code_ptr, const std::string &mod,
const ImportMap &imports) const {
auto &code = *code_ptr;
code = code + "# " + FlatBuffersGeneratedWarning() + "\n\n";
code += "# namespace: " + name_space_name + "\n\n";
if (needs_imports) {
const std::string local_import = "." + mod;
code += "import flatbuffers\n";
code += "from flatbuffers.compat import import_numpy\n";
if (parser_.opts.python_typing) {
code += "from typing import Any\n";
for (auto import_entry : imports) {
// If we have a file called, say, "MyType.py" and in it we have a
// class "MyType", we can generate imports -- usually when we
// have a type that contains arrays of itself -- of the type
// "from .MyType import MyType", which Python can't resolve. So
// if we are trying to import ourself, we skip.
if (import_entry.first != local_import) {
code += "from " + import_entry.first + " import " +
import_entry.second + "\n";
}
}
}
code += "np = import_numpy()\n\n";
}
}
// Save out the generated code for a Python Table type.
bool SaveType(const std::string &defname, const Namespace &ns,
const std::string &classcode, const ImportMap &imports,
const std::string &mod, bool needs_imports) const {
if (!classcode.length()) return true;
std::string code = "";
BeginFile(LastNamespacePart(ns), needs_imports, &code, mod, imports);
code += classcode;
const std::string directories =
parser_.opts.one_file ? path_ : namer_.Directories(ns.components);
EnsureDirExists(directories);
for (size_t i = path_.size() + 1; i != std::string::npos;
i = directories.find(kPathSeparator, i + 1)) {
const std::string init_py =
directories.substr(0, i) + kPathSeparator + "__init__.py";
SaveFile(init_py.c_str(), "", false);
}
const std::string filename = directories + defname;
return SaveFile(filename.c_str(), code, false);
}
private:
const SimpleFloatConstantGenerator float_const_gen_;
const IdlNamer namer_;
};
} // namespace python
static bool GeneratePython(const Parser &parser, const std::string &path,
const std::string &file_name) {
python::PythonGenerator generator(parser, path, file_name);
return generator.generate();
}
namespace {
class PythonCodeGenerator : public CodeGenerator {
public:
Status GenerateCode(const Parser &parser, const std::string &path,
const std::string &filename) override {
if (!GeneratePython(parser, path, filename)) { return Status::ERROR; }
return Status::OK;
}
Status GenerateCode(const uint8_t *, int64_t,
const CodeGenOptions &) override {
return Status::NOT_IMPLEMENTED;
}
Status GenerateMakeRule(const Parser &parser, const std::string &path,
const std::string &filename,
std::string &output) override {
(void)parser;
(void)path;
(void)filename;
(void)output;
return Status::NOT_IMPLEMENTED;
}
Status GenerateGrpcCode(const Parser &parser, const std::string &path,
const std::string &filename) override {
if (!GeneratePythonGRPC(parser, path, filename)) { return Status::ERROR; }
return Status::OK;
}
Status GenerateRootFile(const Parser &parser,
const std::string &path) override {
(void)parser;
(void)path;
return Status::NOT_IMPLEMENTED;
}
bool IsSchemaOnly() const override { return true; }
bool SupportsBfbsGeneration() const override { return false; }
bool SupportsRootFileGeneration() const override { return false; }
IDLOptions::Language Language() const override { return IDLOptions::kPython; }
std::string LanguageName() const override { return "Python"; }
};
} // namespace
std::unique_ptr<CodeGenerator> NewPythonCodeGenerator() {
return std::unique_ptr<PythonCodeGenerator>(new PythonCodeGenerator());
}
} // namespace flatbuffers