1 /*
2 * Copyright 2014 Google Inc. All rights reserved.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 // independent from idl_parser, since this code is not needed for most clients
18
19 #include <string>
20 #include <unordered_set>
21
22 #include "flatbuffers/code_generators.h"
23 #include "flatbuffers/flatbuffers.h"
24 #include "flatbuffers/idl.h"
25 #include "flatbuffers/util.h"
26
27 namespace flatbuffers {
28 namespace lua {
29
30 // Hardcode spaces per indentation.
31 const CommentConfig def_comment = { nullptr, "--", nullptr };
32 const char *Indent = " ";
33 const char *Comment = "-- ";
34 const char *End = "end\n";
35 const char *EndFunc = "end\n";
36 const char *SelfData = "self.view";
37 const char *SelfDataPos = "self.view.pos";
38 const char *SelfDataBytes = "self.view.bytes";
39
40 class LuaGenerator : public BaseGenerator {
41 public:
LuaGenerator(const Parser & parser,const std::string & path,const std::string & file_name)42 LuaGenerator(const Parser &parser, const std::string &path,
43 const std::string &file_name)
44 : BaseGenerator(parser, path, file_name, "" /* not used */,
45 "" /* not used */, "lua") {
46 static const char *const keywords[] = {
47 "and", "break", "do", "else", "elseif", "end", "false", "for",
48 "function", "goto", "if", "in", "local", "nil", "not", "or",
49 "repeat", "return", "then", "true", "until", "while"
50 };
51 keywords_.insert(std::begin(keywords), std::end(keywords));
52 }
53
54 // Most field accessors need to retrieve and test the field offset first,
55 // this is the prefix code for that.
OffsetPrefix(const FieldDef & field)56 std::string OffsetPrefix(const FieldDef &field) {
57 return std::string(Indent) + "local o = " + SelfData + ":Offset(" +
58 NumToString(field.value.offset) + ")\n" + Indent +
59 "if o ~= 0 then\n";
60 }
61
62 // Begin a class declaration.
BeginClass(const StructDef & struct_def,std::string * code_ptr)63 void BeginClass(const StructDef &struct_def, std::string *code_ptr) {
64 std::string &code = *code_ptr;
65 code += "local " + NormalizedName(struct_def) + " = {} -- the module\n";
66 code += "local " + NormalizedMetaName(struct_def) +
67 " = {} -- the class metatable\n";
68 code += "\n";
69 }
70
71 // Begin enum code with a class declaration.
BeginEnum(const std::string & class_name,std::string * code_ptr)72 void BeginEnum(const std::string &class_name, std::string *code_ptr) {
73 std::string &code = *code_ptr;
74 code += "local " + class_name + " = {\n";
75 }
76
EscapeKeyword(const std::string & name) const77 std::string EscapeKeyword(const std::string &name) const {
78 return keywords_.find(name) == keywords_.end() ? name : "_" + name;
79 }
80
NormalizedName(const Definition & definition) const81 std::string NormalizedName(const Definition &definition) const {
82 return EscapeKeyword(definition.name);
83 }
84
NormalizedName(const EnumVal & ev) const85 std::string NormalizedName(const EnumVal &ev) const {
86 return EscapeKeyword(ev.name);
87 }
88
NormalizedMetaName(const Definition & definition) const89 std::string NormalizedMetaName(const Definition &definition) const {
90 return EscapeKeyword(definition.name) + "_mt";
91 }
92
93 // A single enum member.
EnumMember(const EnumDef & enum_def,const EnumVal & ev,std::string * code_ptr)94 void EnumMember(const EnumDef &enum_def, const EnumVal &ev,
95 std::string *code_ptr) {
96 std::string &code = *code_ptr;
97 code += std::string(Indent) + NormalizedName(ev) + " = " +
98 enum_def.ToString(ev) + ",\n";
99 }
100
101 // End enum code.
EndEnum(std::string * code_ptr)102 void EndEnum(std::string *code_ptr) {
103 std::string &code = *code_ptr;
104 code += "}\n";
105 }
106
GenerateNewObjectPrototype(const StructDef & struct_def,std::string * code_ptr)107 void GenerateNewObjectPrototype(const StructDef &struct_def,
108 std::string *code_ptr) {
109 std::string &code = *code_ptr;
110
111 code += "function " + NormalizedName(struct_def) + ".New()\n";
112 code += std::string(Indent) + "local o = {}\n";
113 code += std::string(Indent) +
114 "setmetatable(o, {__index = " + NormalizedMetaName(struct_def) +
115 "})\n";
116 code += std::string(Indent) + "return o\n";
117 code += EndFunc;
118 }
119
120 // Initialize a new struct or table from existing data.
NewRootTypeFromBuffer(const StructDef & struct_def,std::string * code_ptr)121 void NewRootTypeFromBuffer(const StructDef &struct_def,
122 std::string *code_ptr) {
123 std::string &code = *code_ptr;
124
125 code += "function " + NormalizedName(struct_def) + ".GetRootAs" +
126 NormalizedName(struct_def) + "(buf, offset)\n";
127 code += std::string(Indent) +
128 "local n = flatbuffers.N.UOffsetT:Unpack(buf, offset)\n";
129 code += std::string(Indent) + "local o = " + NormalizedName(struct_def) +
130 ".New()\n";
131 code += std::string(Indent) + "o:Init(buf, n + offset)\n";
132 code += std::string(Indent) + "return o\n";
133 code += EndFunc;
134 }
135
136 // Initialize an existing object with other data, to avoid an allocation.
InitializeExisting(const StructDef & struct_def,std::string * code_ptr)137 void InitializeExisting(const StructDef &struct_def, std::string *code_ptr) {
138 std::string &code = *code_ptr;
139
140 GenReceiver(struct_def, code_ptr);
141 code += "Init(buf, pos)\n";
142 code +=
143 std::string(Indent) + SelfData + " = flatbuffers.view.New(buf, pos)\n";
144 code += EndFunc;
145 }
146
147 // Get the length of a vector.
GetVectorLen(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)148 void GetVectorLen(const StructDef &struct_def, const FieldDef &field,
149 std::string *code_ptr) {
150 std::string &code = *code_ptr;
151
152 GenReceiver(struct_def, code_ptr);
153 code += MakeCamel(NormalizedName(field)) + "Length()\n";
154 code += OffsetPrefix(field);
155 code +=
156 std::string(Indent) + Indent + "return " + SelfData + ":VectorLen(o)\n";
157 code += std::string(Indent) + End;
158 code += std::string(Indent) + "return 0\n";
159 code += EndFunc;
160 }
161
162 // Get the value of a struct's scalar.
GetScalarFieldOfStruct(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)163 void GetScalarFieldOfStruct(const StructDef &struct_def,
164 const FieldDef &field, std::string *code_ptr) {
165 std::string &code = *code_ptr;
166 std::string getter = GenGetter(field.value.type);
167 GenReceiver(struct_def, code_ptr);
168 code += MakeCamel(NormalizedName(field));
169 code += "()\n";
170 code += std::string(Indent) + "return " + getter;
171 code += std::string(SelfDataPos) + " + " + NumToString(field.value.offset) +
172 ")\n";
173 code += EndFunc;
174 }
175
176 // Get the value of a table's scalar.
GetScalarFieldOfTable(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)177 void GetScalarFieldOfTable(const StructDef &struct_def, const FieldDef &field,
178 std::string *code_ptr) {
179 std::string &code = *code_ptr;
180 std::string getter = GenGetter(field.value.type);
181 GenReceiver(struct_def, code_ptr);
182 code += MakeCamel(NormalizedName(field));
183 code += "()\n";
184 code += OffsetPrefix(field);
185 getter += std::string("o + ") + SelfDataPos + ")";
186 auto is_bool = field.value.type.base_type == BASE_TYPE_BOOL;
187 if (is_bool) { getter = "(" + getter + " ~= 0)"; }
188 code += std::string(Indent) + Indent + "return " + getter + "\n";
189 code += std::string(Indent) + End;
190 std::string default_value;
191 if (is_bool) {
192 default_value = field.value.constant == "0" ? "false" : "true";
193 } else {
194 default_value = field.value.constant;
195 }
196 code += std::string(Indent) + "return " + default_value + "\n";
197 code += EndFunc;
198 }
199
200 // Get a struct by initializing an existing struct.
201 // Specific to Struct.
GetStructFieldOfStruct(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)202 void GetStructFieldOfStruct(const StructDef &struct_def,
203 const FieldDef &field, std::string *code_ptr) {
204 std::string &code = *code_ptr;
205 GenReceiver(struct_def, code_ptr);
206 code += MakeCamel(NormalizedName(field));
207 code += "(obj)\n";
208 code += std::string(Indent) + "obj:Init(" + SelfDataBytes + ", " +
209 SelfDataPos + " + ";
210 code += NumToString(field.value.offset) + ")\n";
211 code += std::string(Indent) + "return obj\n";
212 code += EndFunc;
213 }
214
215 // Get a struct by initializing an existing struct.
216 // Specific to Table.
GetStructFieldOfTable(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)217 void GetStructFieldOfTable(const StructDef &struct_def, const FieldDef &field,
218 std::string *code_ptr) {
219 std::string &code = *code_ptr;
220 GenReceiver(struct_def, code_ptr);
221 code += MakeCamel(NormalizedName(field));
222 code += "()\n";
223 code += OffsetPrefix(field);
224 if (field.value.type.struct_def->fixed) {
225 code +=
226 std::string(Indent) + Indent + "local x = o + " + SelfDataPos + "\n";
227 } else {
228 code += std::string(Indent) + Indent + "local x = " + SelfData +
229 ":Indirect(o + " + SelfDataPos + ")\n";
230 }
231 code += std::string(Indent) + Indent + "local obj = require('" +
232 TypeNameWithNamespace(field) + "').New()\n";
233 code +=
234 std::string(Indent) + Indent + "obj:Init(" + SelfDataBytes + ", x)\n";
235 code += std::string(Indent) + Indent + "return obj\n";
236 code += std::string(Indent) + End;
237 code += EndFunc;
238 }
239
240 // Get the value of a string.
GetStringField(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)241 void GetStringField(const StructDef &struct_def, const FieldDef &field,
242 std::string *code_ptr) {
243 std::string &code = *code_ptr;
244 GenReceiver(struct_def, code_ptr);
245 code += MakeCamel(NormalizedName(field));
246 code += "()\n";
247 code += OffsetPrefix(field);
248 code +=
249 std::string(Indent) + Indent + "return " + GenGetter(field.value.type);
250 code += std::string("o + ") + SelfDataPos + ")\n";
251 code += std::string(Indent) + End;
252 code += EndFunc;
253 }
254
255 // Get the value of a union from an object.
GetUnionField(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)256 void GetUnionField(const StructDef &struct_def, const FieldDef &field,
257 std::string *code_ptr) {
258 std::string &code = *code_ptr;
259 GenReceiver(struct_def, code_ptr);
260 code += MakeCamel(NormalizedName(field)) + "()\n";
261 code += OffsetPrefix(field);
262
263 // TODO(rw): this works and is not the good way to it:
264 // bool is_native_table = TypeName(field) == "*flatbuffers.Table";
265 // if (is_native_table) {
266 // code += std::string(Indent) + Indent + "from flatbuffers.table import
267 // Table\n";
268 //} else {
269 // code += std::string(Indent) + Indent +
270 // code += "from ." + TypeName(field) + " import " + TypeName(field) +
271 // "\n";
272 //}
273 code +=
274 std::string(Indent) + Indent +
275 "local obj = "
276 "flatbuffers.view.New(require('flatbuffers.binaryarray').New(0), 0)\n";
277 code += std::string(Indent) + Indent + GenGetter(field.value.type) +
278 "obj, o)\n";
279 code += std::string(Indent) + Indent + "return obj\n";
280 code += std::string(Indent) + End;
281 code += EndFunc;
282 }
283
284 // Get the value of a vector's struct member.
GetMemberOfVectorOfStruct(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)285 void GetMemberOfVectorOfStruct(const StructDef &struct_def,
286 const FieldDef &field, std::string *code_ptr) {
287 std::string &code = *code_ptr;
288 auto vectortype = field.value.type.VectorType();
289
290 GenReceiver(struct_def, code_ptr);
291 code += MakeCamel(NormalizedName(field));
292 code += "(j)\n";
293 code += OffsetPrefix(field);
294 code +=
295 std::string(Indent) + Indent + "local x = " + SelfData + ":Vector(o)\n";
296 code += std::string(Indent) + Indent + "x = x + ((j-1) * ";
297 code += NumToString(InlineSize(vectortype)) + ")\n";
298 if (!(vectortype.struct_def->fixed)) {
299 code +=
300 std::string(Indent) + Indent + "x = " + SelfData + ":Indirect(x)\n";
301 }
302 code += std::string(Indent) + Indent + "local obj = require('" +
303 TypeNameWithNamespace(field) + "').New()\n";
304 code +=
305 std::string(Indent) + Indent + "obj:Init(" + SelfDataBytes + ", x)\n";
306 code += std::string(Indent) + Indent + "return obj\n";
307 code += std::string(Indent) + End;
308 code += EndFunc;
309 }
310
311 // Get the value of a vector's non-struct member. Uses a named return
312 // argument to conveniently set the zero value for the result.
GetMemberOfVectorOfNonStruct(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)313 void GetMemberOfVectorOfNonStruct(const StructDef &struct_def,
314 const FieldDef &field,
315 std::string *code_ptr) {
316 std::string &code = *code_ptr;
317 auto vectortype = field.value.type.VectorType();
318
319 GenReceiver(struct_def, code_ptr);
320 code += MakeCamel(NormalizedName(field));
321 code += "(j)\n";
322 code += OffsetPrefix(field);
323 code +=
324 std::string(Indent) + Indent + "local a = " + SelfData + ":Vector(o)\n";
325 code += std::string(Indent) + Indent;
326 code += "return " + GenGetter(field.value.type);
327 code += "a + ((j-1) * ";
328 code += NumToString(InlineSize(vectortype)) + "))\n";
329 code += std::string(Indent) + End;
330 if (vectortype.base_type == BASE_TYPE_STRING) {
331 code += std::string(Indent) + "return ''\n";
332 } else {
333 code += std::string(Indent) + "return 0\n";
334 }
335 code += EndFunc;
336 }
337
338 // Begin the creator function signature.
BeginBuilderArgs(const StructDef & struct_def,std::string * code_ptr)339 void BeginBuilderArgs(const StructDef &struct_def, std::string *code_ptr) {
340 std::string &code = *code_ptr;
341
342 code += "function " + NormalizedName(struct_def) + ".Create" +
343 NormalizedName(struct_def);
344 code += "(builder";
345 }
346
347 // Recursively generate arguments for a constructor, to deal with nested
348 // structs.
StructBuilderArgs(const StructDef & struct_def,const char * nameprefix,std::string * code_ptr)349 void StructBuilderArgs(const StructDef &struct_def, const char *nameprefix,
350 std::string *code_ptr) {
351 for (auto it = struct_def.fields.vec.begin();
352 it != struct_def.fields.vec.end(); ++it) {
353 auto &field = **it;
354 if (IsStruct(field.value.type)) {
355 // Generate arguments for a struct inside a struct. To ensure names
356 // don't clash, and to make it obvious these arguments are constructing
357 // a nested struct, prefix the name with the field name.
358 StructBuilderArgs(*field.value.type.struct_def,
359 (nameprefix + (NormalizedName(field) + "_")).c_str(),
360 code_ptr);
361 } else {
362 std::string &code = *code_ptr;
363 code += std::string(", ") + nameprefix;
364 code += MakeCamel(NormalizedName(field), false);
365 }
366 }
367 }
368
369 // End the creator function signature.
EndBuilderArgs(std::string * code_ptr)370 void EndBuilderArgs(std::string *code_ptr) {
371 std::string &code = *code_ptr;
372 code += ")\n";
373 }
374
375 // Recursively generate struct construction statements and instert manual
376 // padding.
StructBuilderBody(const StructDef & struct_def,const char * nameprefix,std::string * code_ptr)377 void StructBuilderBody(const StructDef &struct_def, const char *nameprefix,
378 std::string *code_ptr) {
379 std::string &code = *code_ptr;
380 code += std::string(Indent) + "builder:Prep(" +
381 NumToString(struct_def.minalign) + ", ";
382 code += NumToString(struct_def.bytesize) + ")\n";
383 for (auto it = struct_def.fields.vec.rbegin();
384 it != struct_def.fields.vec.rend(); ++it) {
385 auto &field = **it;
386 if (field.padding)
387 code += std::string(Indent) + "builder:Pad(" +
388 NumToString(field.padding) + ")\n";
389 if (IsStruct(field.value.type)) {
390 StructBuilderBody(*field.value.type.struct_def,
391 (nameprefix + (NormalizedName(field) + "_")).c_str(),
392 code_ptr);
393 } else {
394 code +=
395 std::string(Indent) + "builder:Prepend" + GenMethod(field) + "(";
396 code += nameprefix + MakeCamel(NormalizedName(field), false) + ")\n";
397 }
398 }
399 }
400
EndBuilderBody(std::string * code_ptr)401 void EndBuilderBody(std::string *code_ptr) {
402 std::string &code = *code_ptr;
403 code += std::string(Indent) + "return builder:Offset()\n";
404 code += EndFunc;
405 }
406
407 // Get the value of a table's starting offset.
GetStartOfTable(const StructDef & struct_def,std::string * code_ptr)408 void GetStartOfTable(const StructDef &struct_def, std::string *code_ptr) {
409 std::string &code = *code_ptr;
410 code += "function " + NormalizedName(struct_def) + ".Start";
411 code += "(builder) ";
412 code += "builder:StartObject(";
413 code += NumToString(struct_def.fields.vec.size());
414 code += ") end\n";
415 }
416
417 // Set the value of a table's field.
BuildFieldOfTable(const StructDef & struct_def,const FieldDef & field,const size_t offset,std::string * code_ptr)418 void BuildFieldOfTable(const StructDef &struct_def, const FieldDef &field,
419 const size_t offset, std::string *code_ptr) {
420 std::string &code = *code_ptr;
421 code += "function " + NormalizedName(struct_def) + ".Add" +
422 MakeCamel(NormalizedName(field));
423 code += "(builder, ";
424 code += MakeCamel(NormalizedName(field), false);
425 code += ") ";
426 code += "builder:Prepend";
427 code += GenMethod(field) + "Slot(";
428 code += NumToString(offset) + ", ";
429 // todo: i don't need to cast in Lua, but am I missing something?
430 // if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
431 // code += "flatbuffers.N.UOffsetTFlags.py_type";
432 // code += "(";
433 // code += MakeCamel(NormalizedName(field), false) + ")";
434 // } else {
435 code += MakeCamel(NormalizedName(field), false);
436 // }
437 code += ", " + field.value.constant;
438 code += ") end\n";
439 }
440
441 // Set the value of one of the members of a table's vector.
BuildVectorOfTable(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)442 void BuildVectorOfTable(const StructDef &struct_def, const FieldDef &field,
443 std::string *code_ptr) {
444 std::string &code = *code_ptr;
445 code += "function " + NormalizedName(struct_def) + ".Start";
446 code += MakeCamel(NormalizedName(field));
447 code += "Vector(builder, numElems) return builder:StartVector(";
448 auto vector_type = field.value.type.VectorType();
449 auto alignment = InlineAlignment(vector_type);
450 auto elem_size = InlineSize(vector_type);
451 code += NumToString(elem_size);
452 code += ", numElems, " + NumToString(alignment);
453 code += ") end\n";
454 }
455
456 // Get the offset of the end of a table.
GetEndOffsetOnTable(const StructDef & struct_def,std::string * code_ptr)457 void GetEndOffsetOnTable(const StructDef &struct_def, std::string *code_ptr) {
458 std::string &code = *code_ptr;
459 code += "function " + NormalizedName(struct_def) + ".End";
460 code += "(builder) ";
461 code += "return builder:EndObject() end\n";
462 }
463
464 // Generate the receiver for function signatures.
GenReceiver(const StructDef & struct_def,std::string * code_ptr)465 void GenReceiver(const StructDef &struct_def, std::string *code_ptr) {
466 std::string &code = *code_ptr;
467 code += "function " + NormalizedMetaName(struct_def) + ":";
468 }
469
470 // Generate a struct field, conditioned on its child type(s).
GenStructAccessor(const StructDef & struct_def,const FieldDef & field,std::string * code_ptr)471 void GenStructAccessor(const StructDef &struct_def, const FieldDef &field,
472 std::string *code_ptr) {
473 GenComment(field.doc_comment, code_ptr, &def_comment);
474 if (IsScalar(field.value.type.base_type)) {
475 if (struct_def.fixed) {
476 GetScalarFieldOfStruct(struct_def, field, code_ptr);
477 } else {
478 GetScalarFieldOfTable(struct_def, field, code_ptr);
479 }
480 } else {
481 switch (field.value.type.base_type) {
482 case BASE_TYPE_STRUCT:
483 if (struct_def.fixed) {
484 GetStructFieldOfStruct(struct_def, field, code_ptr);
485 } else {
486 GetStructFieldOfTable(struct_def, field, code_ptr);
487 }
488 break;
489 case BASE_TYPE_STRING:
490 GetStringField(struct_def, field, code_ptr);
491 break;
492 case BASE_TYPE_VECTOR: {
493 auto vectortype = field.value.type.VectorType();
494 if (vectortype.base_type == BASE_TYPE_STRUCT) {
495 GetMemberOfVectorOfStruct(struct_def, field, code_ptr);
496 } else {
497 GetMemberOfVectorOfNonStruct(struct_def, field, code_ptr);
498 }
499 break;
500 }
501 case BASE_TYPE_UNION: GetUnionField(struct_def, field, code_ptr); break;
502 default: FLATBUFFERS_ASSERT(0);
503 }
504 }
505 if (field.value.type.base_type == BASE_TYPE_VECTOR) {
506 GetVectorLen(struct_def, field, code_ptr);
507 }
508 }
509
510 // Generate table constructors, conditioned on its members' types.
GenTableBuilders(const StructDef & struct_def,std::string * code_ptr)511 void GenTableBuilders(const StructDef &struct_def, std::string *code_ptr) {
512 GetStartOfTable(struct_def, code_ptr);
513
514 for (auto it = struct_def.fields.vec.begin();
515 it != struct_def.fields.vec.end(); ++it) {
516 auto &field = **it;
517 if (field.deprecated) continue;
518
519 auto offset = it - struct_def.fields.vec.begin();
520 BuildFieldOfTable(struct_def, field, offset, code_ptr);
521 if (field.value.type.base_type == BASE_TYPE_VECTOR) {
522 BuildVectorOfTable(struct_def, field, code_ptr);
523 }
524 }
525
526 GetEndOffsetOnTable(struct_def, code_ptr);
527 }
528
529 // Generate struct or table methods.
GenStruct(const StructDef & struct_def,std::string * code_ptr)530 void GenStruct(const StructDef &struct_def, std::string *code_ptr) {
531 if (struct_def.generated) return;
532
533 GenComment(struct_def.doc_comment, code_ptr, &def_comment);
534 BeginClass(struct_def, code_ptr);
535
536 GenerateNewObjectPrototype(struct_def, code_ptr);
537
538 if (!struct_def.fixed) {
539 // Generate a special accessor for the table that has been declared as
540 // the root type.
541 NewRootTypeFromBuffer(struct_def, code_ptr);
542 }
543
544 // Generate the Init method that sets the field in a pre-existing
545 // accessor object. This is to allow object reuse.
546 InitializeExisting(struct_def, code_ptr);
547 for (auto it = struct_def.fields.vec.begin();
548 it != struct_def.fields.vec.end(); ++it) {
549 auto &field = **it;
550 if (field.deprecated) continue;
551
552 GenStructAccessor(struct_def, field, code_ptr);
553 }
554
555 if (struct_def.fixed) {
556 // create a struct constructor function
557 GenStructBuilder(struct_def, code_ptr);
558 } else {
559 // Create a set of functions that allow table construction.
560 GenTableBuilders(struct_def, code_ptr);
561 }
562 }
563
564 // Generate enum declarations.
GenEnum(const EnumDef & enum_def,std::string * code_ptr)565 void GenEnum(const EnumDef &enum_def, std::string *code_ptr) {
566 if (enum_def.generated) return;
567
568 GenComment(enum_def.doc_comment, code_ptr, &def_comment);
569 BeginEnum(NormalizedName(enum_def), code_ptr);
570 for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
571 auto &ev = **it;
572 GenComment(ev.doc_comment, code_ptr, &def_comment, Indent);
573 EnumMember(enum_def, ev, code_ptr);
574 }
575 EndEnum(code_ptr);
576 }
577
578 // Returns the function name that is able to read a value of the given type.
GenGetter(const Type & type)579 std::string GenGetter(const Type &type) {
580 switch (type.base_type) {
581 case BASE_TYPE_STRING: return std::string(SelfData) + ":String(";
582 case BASE_TYPE_UNION: return std::string(SelfData) + ":Union(";
583 case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());
584 default:
585 return std::string(SelfData) + ":Get(flatbuffers.N." +
586 MakeCamel(GenTypeGet(type)) + ", ";
587 }
588 }
589
590 // Returns the method name for use with add/put calls.
GenMethod(const FieldDef & field)591 std::string GenMethod(const FieldDef &field) {
592 return IsScalar(field.value.type.base_type)
593 ? MakeCamel(GenTypeBasic(field.value.type))
594 : (IsStruct(field.value.type) ? "Struct" : "UOffsetTRelative");
595 }
596
GenTypeBasic(const Type & type)597 std::string GenTypeBasic(const Type &type) {
598 // clang-format off
599 static const char *ctypename[] = {
600 #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
601 CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, ...) \
602 #PTYPE,
603 FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
604 #undef FLATBUFFERS_TD
605 };
606 // clang-format on
607 return ctypename[type.base_type];
608 }
609
GenTypePointer(const Type & type)610 std::string GenTypePointer(const Type &type) {
611 switch (type.base_type) {
612 case BASE_TYPE_STRING: return "string";
613 case BASE_TYPE_VECTOR: return GenTypeGet(type.VectorType());
614 case BASE_TYPE_STRUCT: return type.struct_def->name;
615 case BASE_TYPE_UNION:
616 // fall through
617 default: return "*flatbuffers.Table";
618 }
619 }
620
GenTypeGet(const Type & type)621 std::string GenTypeGet(const Type &type) {
622 return IsScalar(type.base_type) ? GenTypeBasic(type) : GenTypePointer(type);
623 }
624
GetNamespace(const Type & type)625 std::string GetNamespace(const Type &type) {
626 return type.struct_def->defined_namespace->GetFullyQualifiedName(
627 type.struct_def->name);
628 }
629
TypeName(const FieldDef & field)630 std::string TypeName(const FieldDef &field) {
631 return GenTypeGet(field.value.type);
632 }
633
TypeNameWithNamespace(const FieldDef & field)634 std::string TypeNameWithNamespace(const FieldDef &field) {
635 return GetNamespace(field.value.type);
636 }
637
638 // Create a struct with a builder and the struct's arguments.
GenStructBuilder(const StructDef & struct_def,std::string * code_ptr)639 void GenStructBuilder(const StructDef &struct_def, std::string *code_ptr) {
640 BeginBuilderArgs(struct_def, code_ptr);
641 StructBuilderArgs(struct_def, "", code_ptr);
642 EndBuilderArgs(code_ptr);
643
644 StructBuilderBody(struct_def, "", code_ptr);
645 EndBuilderBody(code_ptr);
646 }
647
generate()648 bool generate() {
649 if (!generateEnums()) return false;
650 if (!generateStructs()) return false;
651 return true;
652 }
653
654 private:
generateEnums()655 bool generateEnums() {
656 for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
657 ++it) {
658 auto &enum_def = **it;
659 std::string enumcode;
660 GenEnum(enum_def, &enumcode);
661 if (!SaveType(enum_def, enumcode, false)) return false;
662 }
663 return true;
664 }
665
generateStructs()666 bool generateStructs() {
667 for (auto it = parser_.structs_.vec.begin();
668 it != parser_.structs_.vec.end(); ++it) {
669 auto &struct_def = **it;
670 std::string declcode;
671 GenStruct(struct_def, &declcode);
672 if (!SaveType(struct_def, declcode, true)) return false;
673 }
674 return true;
675 }
676
677 // Begin by declaring namespace and imports.
BeginFile(const std::string & name_space_name,const bool needs_imports,std::string * code_ptr)678 void BeginFile(const std::string &name_space_name, const bool needs_imports,
679 std::string *code_ptr) {
680 std::string &code = *code_ptr;
681 code += std::string(Comment) + FlatBuffersGeneratedWarning() + "\n\n";
682 code += std::string(Comment) + "namespace: " + name_space_name + "\n\n";
683 if (needs_imports) {
684 code += "local flatbuffers = require('flatbuffers')\n\n";
685 }
686 }
687
688 // Save out the generated code for a Lua Table type.
SaveType(const Definition & def,const std::string & classcode,bool needs_imports)689 bool SaveType(const Definition &def, const std::string &classcode,
690 bool needs_imports) {
691 if (!classcode.length()) return true;
692
693 std::string namespace_dir = path_;
694 auto &namespaces = def.defined_namespace->components;
695 for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
696 if (it != namespaces.begin()) namespace_dir += kPathSeparator;
697 namespace_dir += *it;
698 // std::string init_py_filename = namespace_dir + "/__init__.py";
699 // SaveFile(init_py_filename.c_str(), "", false);
700 }
701
702 std::string code = "";
703 BeginFile(LastNamespacePart(*def.defined_namespace), needs_imports, &code);
704 code += classcode;
705 code += "\n";
706 code +=
707 "return " + NormalizedName(def) + " " + Comment + "return the module";
708 std::string filename =
709 NamespaceDir(*def.defined_namespace) + NormalizedName(def) + ".lua";
710 return SaveFile(filename.c_str(), code, false);
711 }
712
713 private:
714 std::unordered_set<std::string> keywords_;
715 };
716
717 } // namespace lua
718
GenerateLua(const Parser & parser,const std::string & path,const std::string & file_name)719 bool GenerateLua(const Parser &parser, const std::string &path,
720 const std::string &file_name) {
721 lua::LuaGenerator generator(parser, path, file_name);
722 return generator.generate();
723 }
724
725 } // namespace flatbuffers
726