Squashed 'third_party/flatbuffers/' content from commit acc9990ab
Change-Id: I48550d40d78fea996ebe74e9723a5d1f910de491
git-subtree-dir: third_party/flatbuffers
git-subtree-split: acc9990abd2206491480291b0f85f925110102ea
diff --git a/src/idl_gen_python.cpp b/src/idl_gen_python.cpp
new file mode 100644
index 0000000..c8db359
--- /dev/null
+++ b/src/idl_gen_python.cpp
@@ -0,0 +1,823 @@
+/*
+ * 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 <string>
+
+#include "flatbuffers/code_generators.h"
+#include "flatbuffers/flatbuffers.h"
+#include "flatbuffers/idl.h"
+#include "flatbuffers/util.h"
+
+#include <unordered_set>
+
+namespace flatbuffers {
+namespace python {
+
+// Hardcode spaces per indentation.
+const CommentConfig def_comment = { nullptr, "#", nullptr };
+const std::string Indent = " ";
+
+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 */),
+ float_const_gen_("float('nan')", "float('inf')", "float('-inf')") {
+ static const char * const keywords[] = {
+ "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"
+ };
+ keywords_.insert(std::begin(keywords), std::end(keywords));
+ }
+
+ // 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) {
+ return "\n" + Indent + Indent +
+ "o = flatbuffers.number_types.UOffsetTFlags.py_type" +
+ "(self._tab.Offset(" + NumToString(field.value.offset) + "))\n" +
+ Indent + Indent + "if o != 0:\n";
+ }
+
+ // Begin a class declaration.
+ void BeginClass(const StructDef &struct_def, std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ code += "class " + NormalizedName(struct_def) + "(object):\n";
+ code += Indent + "__slots__ = ['_tab']";
+ code += "\n\n";
+ }
+
+ // Begin enum code with a class declaration.
+ void BeginEnum(const std::string &class_name, std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ code += "class " + class_name + "(object):\n";
+ }
+
+ std::string EscapeKeyword(const std::string &name) const {
+ return keywords_.find(name) == keywords_.end() ? name : name + "_";
+ }
+
+ std::string NormalizedName(const Definition &definition) const {
+ return EscapeKeyword(definition.name);
+ }
+
+ std::string NormalizedName(const EnumVal &ev) const {
+ return EscapeKeyword(ev.name);
+ }
+
+ // A single enum member.
+ void EnumMember(const EnumDef &enum_def, const EnumVal &ev,
+ std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ code += Indent;
+ code += NormalizedName(ev);
+ code += " = ";
+ code += enum_def.ToString(ev) + "\n";
+ }
+
+ // End enum code.
+ void EndEnum(std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ code += "\n";
+ }
+
+ // Initialize a new struct or table from existing data.
+ void NewRootTypeFromBuffer(const StructDef &struct_def,
+ std::string *code_ptr) {
+ std::string &code = *code_ptr;
+
+ code += Indent + "@classmethod\n";
+ code += Indent + "def GetRootAs";
+ code += NormalizedName(struct_def);
+ code += "(cls, buf, offset):";
+ code += "\n";
+ code += Indent + Indent;
+ code += "n = flatbuffers.encode.Get";
+ code += "(flatbuffers.packer.uoffset, buf, offset)\n";
+ code += Indent + Indent + "x = " + NormalizedName(struct_def) + "()\n";
+ code += Indent + Indent + "x.Init(buf, n + offset)\n";
+ code += Indent + Indent + "return x\n";
+ code += "\n";
+ }
+
+ // Initialize an existing object with other data, to avoid an allocation.
+ void InitializeExisting(const StructDef &struct_def,
+ std::string *code_ptr) {
+ std::string &code = *code_ptr;
+
+ GenReceiver(struct_def, code_ptr);
+ 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) {
+ std::string &code = *code_ptr;
+
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(field)) + "Length(self";
+ code += "):" + OffsetPrefix(field);
+ code += Indent + Indent + Indent + "return self._tab.VectorLen(o)\n";
+ code += Indent + Indent + "return 0\n\n";
+ }
+
+ // Get the value of a struct's scalar.
+ void GetScalarFieldOfStruct(const StructDef &struct_def,
+ const FieldDef &field,
+ std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ std::string getter = GenGetter(field.value.type);
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(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) {
+ std::string &code = *code_ptr;
+ std::string getter = GenGetter(field.value.type);
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(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 (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) {
+ std::string &code = *code_ptr;
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(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) {
+ std::string &code = *code_ptr;
+ const auto vec_type = field.value.type.VectorType();
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(field));
+ if (IsStruct(vec_type)) {
+ code += "(self, obj, i):\n";
+ code += Indent + Indent + "obj.Init(self._tab.Bytes, self._tab.Pos + ";
+ code += NumToString(field.value.offset) + " + i * ";
+ code += NumToString(InlineSize(vec_type));
+ code += ")\n" + Indent + Indent + "return obj\n\n";
+ } else {
+ auto getter = GenGetter(vec_type);
+ code += "(self): return [" + getter;
+ code += "self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(";
+ code += NumToString(field.value.offset) + " + i * ";
+ code += NumToString(InlineSize(vec_type));
+ code += ")) for i in range(";
+ code += NumToString(field.value.type.fixed_length) + ")]\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) {
+ std::string &code = *code_ptr;
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(field));
+ code += "(self):";
+ 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";
+ }
+ code += Indent + Indent + Indent;
+ code += "from ." + TypeName(field) + " import " + TypeName(field) + "\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) {
+ std::string &code = *code_ptr;
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(field));
+ 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) {
+ std::string &code = *code_ptr;
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(field)) + "(self):";
+ code += OffsetPrefix(field);
+
+ // TODO(rw): this works and is not the good way to it:
+ bool is_native_table = TypeName(field) == "*flatbuffers.Table";
+ if (is_native_table) {
+ code += Indent + Indent + Indent + "from flatbuffers.table import Table\n";
+ } else {
+ code += Indent + Indent + Indent;
+ code += "from ." + TypeName(field) + " import " + TypeName(field) + "\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";
+ }
+
+ // Get the value of a vector's struct member.
+ void GetMemberOfVectorOfStruct(const StructDef &struct_def,
+ const FieldDef &field,
+ std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ auto vectortype = field.value.type.VectorType();
+
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(field));
+ code += "(self, j):" + 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";
+ }
+ code += Indent + Indent + Indent;
+ code += "from ." + TypeName(field) + " import " + TypeName(field) + "\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) {
+ std::string &code = *code_ptr;
+ auto vectortype = field.value.type.VectorType();
+
+ GenReceiver(struct_def, code_ptr);
+ code += MakeCamel(NormalizedName(field));
+ code += "(self, j):";
+ 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 (vectortype.base_type == BASE_TYPE_STRING) {
+ 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) {
+ std::string &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 += MakeCamel(NormalizedName(field)) + "AsNumpy(self):";
+ code += OffsetPrefix(field);
+
+ code += Indent + Indent + Indent;
+ code += "return ";
+ code += "self._tab.GetVectorAsNumpy(flatbuffers.number_types.";
+ code += MakeCamel(GenTypeGet(field.value.type));
+ code += "Flags, o)\n";
+
+ if (vectortype.base_type == BASE_TYPE_STRING) {
+ code += Indent + Indent + "return \"\"\n";
+ } else {
+ code += Indent + Indent + "return 0\n";
+ }
+ code += "\n";
+ }
+
+ // Begin the creator function signature.
+ void BeginBuilderArgs(const StructDef &struct_def,
+ std::string *code_ptr) {
+ std::string &code = *code_ptr;
+
+ code += "\n";
+ code += "def Create" + NormalizedName(struct_def);
+ code += "(builder";
+ }
+
+ // Recursively generate arguments for a constructor, to deal with nested
+ // structs.
+ void StructBuilderArgs(const StructDef &struct_def,
+ const char *nameprefix, std::string *code_ptr) {
+ 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.
+ StructBuilderArgs(*field_type.struct_def,
+ (nameprefix + (NormalizedName(field) + "_")).c_str(),
+ code_ptr);
+ } else {
+ std::string &code = *code_ptr;
+ code += std::string(", ") + nameprefix;
+ code += MakeCamel(NormalizedName(field), false);
+ }
+ }
+ }
+
+ // End the creator function signature.
+ void EndBuilderArgs(std::string *code_ptr) {
+ std::string &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) {
+ std::string &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 + (NormalizedName(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 + (NormalizedName(field) + "_")).c_str(), code_ptr,
+ index + 1, in_array);
+ } else {
+ code += IsArray(field_type) ? " " : "";
+ code += indent + " builder.Prepend" + GenMethod(field) + "(";
+ code += nameprefix + MakeCamel(NormalizedName(field), false);
+ 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) {
+ std::string &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) {
+ std::string &code = *code_ptr;
+ code += "def " + NormalizedName(struct_def) + "Start";
+ code += "(builder): ";
+ code += "builder.StartObject(";
+ code += NumToString(struct_def.fields.vec.size());
+ code += ")\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) {
+ std::string &code = *code_ptr;
+ code += "def " + NormalizedName(struct_def) + "Add" + MakeCamel(NormalizedName(field));
+ code += "(builder, ";
+ code += MakeCamel(NormalizedName(field), false);
+ code += "): ";
+ code += "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 += "(";
+ code += MakeCamel(NormalizedName(field), false) + ")";
+ } else {
+ code += MakeCamel(NormalizedName(field), false);
+ }
+ code += ", ";
+ code += IsFloat(field.value.type.base_type)
+ ? float_const_gen_.GenFloatConstant(field)
+ : field.value.constant;
+ code += ")\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) {
+ std::string &code = *code_ptr;
+ code += "def " + NormalizedName(struct_def) + "Start";
+ code += MakeCamel(NormalizedName(field));
+ code += "Vector(builder, numElems): 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";
+ }
+
+ // Get the offset of the end of a table.
+ void GetEndOffsetOnTable(const StructDef &struct_def,
+ std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ code += "def " + NormalizedName(struct_def) + "End";
+ code += "(builder): ";
+ code += "return builder.EndObject()\n";
+ }
+
+ // Generate the receiver for function signatures.
+ void GenReceiver(const StructDef &struct_def, std::string *code_ptr) {
+ std::string &code = *code_ptr;
+ code += Indent + "# " + NormalizedName(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) {
+ 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 if (IsArray(field.value.type)) {
+ GetArrayOfStruct(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);
+ }
+ break;
+ case BASE_TYPE_STRING: GetStringField(struct_def, field, code_ptr); break;
+ case BASE_TYPE_VECTOR: {
+ auto vectortype = field.value.type.VectorType();
+ if (vectortype.base_type == BASE_TYPE_STRUCT) {
+ GetMemberOfVectorOfStruct(struct_def, field, code_ptr);
+ } else {
+ GetMemberOfVectorOfNonStruct(struct_def, field, code_ptr);
+ GetVectorOfNonStructAsNumpy(struct_def, field, code_ptr);
+ }
+ break;
+ }
+ case BASE_TYPE_UNION: GetUnionField(struct_def, field, code_ptr); break;
+ default: FLATBUFFERS_ASSERT(0);
+ }
+ }
+ if (field.value.type.base_type == BASE_TYPE_VECTOR) {
+ GetVectorLen(struct_def, field, code_ptr);
+ }
+ }
+
+ // Generate table constructors, conditioned on its members' types.
+ void GenTableBuilders(const StructDef &struct_def,
+ std::string *code_ptr) {
+ 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 (field.value.type.base_type == BASE_TYPE_VECTOR) {
+ BuildVectorOfTable(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) {
+ std::string &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 " + NormalizedName(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";
+ }
+
+ // Generate struct or table methods.
+ void GenStruct(const StructDef &struct_def, std::string *code_ptr) {
+ 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);
+ }
+ }
+ // Generate 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);
+ }
+
+ if (struct_def.fixed) {
+ // create a struct constructor function
+ GenStructBuilder(struct_def, code_ptr);
+ } else {
+ // Create a set of functions that allow table construction.
+ GenTableBuilders(struct_def, code_ptr);
+ }
+ }
+
+ // Generate enum declarations.
+ void GenEnum(const EnumDef &enum_def, std::string *code_ptr) {
+ if (enum_def.generated) return;
+
+ GenComment(enum_def.doc_comment, code_ptr, &def_comment);
+ BeginEnum(NormalizedName(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);
+ }
+ EndEnum(code_ptr);
+ }
+
+ // Returns the function name that is able to read a value of the given type.
+ std::string GenGetter(const Type &type) {
+ 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." +
+ MakeCamel(GenTypeGet(type)) + "Flags, ";
+ }
+ }
+
+ // Returns the method name for use with add/put calls.
+ std::string GenMethod(const FieldDef &field) {
+ return (IsScalar(field.value.type.base_type) || IsArray(field.value.type))
+ ? MakeCamel(GenTypeBasic(field.value.type))
+ : (IsStruct(field.value.type) ? "Struct" : "UOffsetTRelative");
+ }
+
+ std::string GenTypeBasic(const Type &type) {
+ static const char *ctypename[] = {
+ // clang-format off
+ #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
+ CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+ #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) {
+ switch (type.base_type) {
+ case BASE_TYPE_STRING: return "string";
+ case BASE_TYPE_VECTOR: 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) {
+ return IsScalar(type.base_type) ? GenTypeBasic(type) : GenTypePointer(type);
+ }
+
+ std::string TypeName(const FieldDef &field) {
+ return GenTypeGet(field.value.type);
+ }
+
+ // Create a struct with a builder and the struct's arguments.
+ void GenStructBuilder(const StructDef &struct_def,
+ std::string *code_ptr) {
+ BeginBuilderArgs(struct_def, code_ptr);
+ StructBuilderArgs(struct_def, "", code_ptr);
+ EndBuilderArgs(code_ptr);
+
+ StructBuilderBody(struct_def, "", code_ptr);
+ EndBuilderBody(code_ptr);
+ }
+
+ bool generate() {
+ if (!generateEnums()) return false;
+ if (!generateStructs()) return false;
+ return true;
+ }
+
+ private:
+ bool generateEnums() {
+ 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 (!SaveType(enum_def, enumcode, false)) return false;
+ }
+ return true;
+ }
+
+ bool generateStructs() {
+ for (auto it = parser_.structs_.vec.begin();
+ it != parser_.structs_.vec.end(); ++it) {
+ auto &struct_def = **it;
+ std::string declcode;
+ GenStruct(struct_def, &declcode);
+ if (!SaveType(struct_def, declcode, 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) {
+ std::string &code = *code_ptr;
+ code = code + "# " + FlatBuffersGeneratedWarning() + "\n\n";
+ code += "# namespace: " + name_space_name + "\n\n";
+ if (needs_imports) { code += "import flatbuffers\n\n"; }
+ }
+
+ // Save out the generated code for a Python Table type.
+ bool SaveType(const Definition &def, const std::string &classcode,
+ bool needs_imports) {
+ if (!classcode.length()) return true;
+
+ std::string namespace_dir = path_;
+ auto &namespaces = def.defined_namespace->components;
+ for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
+ if (it != namespaces.begin()) namespace_dir += kPathSeparator;
+ namespace_dir += *it;
+ std::string init_py_filename = namespace_dir + "/__init__.py";
+ SaveFile(init_py_filename.c_str(), "", false);
+ }
+
+ std::string code = "";
+ BeginFile(LastNamespacePart(*def.defined_namespace), needs_imports, &code);
+ code += classcode;
+ std::string filename =
+ NamespaceDir(*def.defined_namespace) + NormalizedName(def) + ".py";
+ return SaveFile(filename.c_str(), code, false);
+ }
+ private:
+ std::unordered_set<std::string> keywords_;
+ const SimpleFloatConstantGenerator float_const_gen_;
+};
+
+} // namespace python
+
+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 flatbuffers