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
27namespace flatbuffers {
28namespace lua {
29
30// Hardcode spaces per indentation.
31const CommentConfig def_comment = { nullptr, "--", nullptr };
32const char *Indent = " ";
33const char *Comment = "-- ";
34const char *End = "end\n";
35const char *EndFunc = "end\n";
36const char *SelfData = "self.view";
37const char *SelfDataPos = "self.view.pos";
38const char *SelfDataBytes = "self.view.bytes";
39
40class LuaGenerator : public BaseGenerator {
41 public:
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.
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.
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.
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
77 std::string EscapeKeyword(const std::string &name) const {
78 return keywords_.find(name) == keywords_.end() ? name : "_" + name;
79 }
80
81 std::string NormalizedName(const Definition &definition) const {
82 return EscapeKeyword(definition.name);
83 }
84
85 std::string NormalizedName(const EnumVal &ev) const {
86 return EscapeKeyword(ev.name);
87 }
88
89 std::string NormalizedMetaName(const Definition &definition) const {
90 return EscapeKeyword(definition.name) + "_mt";
91 }
92
93 // A single enum member.
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.
102 void EndEnum(std::string *code_ptr) {
103 std::string &code = *code_ptr;
104 code += "}\n";
105 }
106
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.
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) + "if type(buf) == \"string\" then\n";
128 code += std::string(Indent) + Indent +
129 "buf = flatbuffers.binaryArray.New(buf)\n";
130 code += std::string(Indent) + "end\n";
131 code += std::string(Indent) +
132 "local n = flatbuffers.N.UOffsetT:Unpack(buf, offset)\n";
133 code += std::string(Indent) + "local o = " + NormalizedName(struct_def) +
134 ".New()\n";
135 code += std::string(Indent) + "o:Init(buf, n + offset)\n";
136 code += std::string(Indent) + "return o\n";
137 code += EndFunc;
138 }
139
140 // Initialize an existing object with other data, to avoid an allocation.
141 void InitializeExisting(const StructDef &struct_def, std::string *code_ptr) {
142 std::string &code = *code_ptr;
143
144 GenReceiver(struct_def, code_ptr);
145 code += "Init(buf, pos)\n";
146 code +=
147 std::string(Indent) + SelfData + " = flatbuffers.view.New(buf, pos)\n";
148 code += EndFunc;
149 }
150
151 // Get the length of a vector.
152 void GetVectorLen(const StructDef &struct_def, const FieldDef &field,
153 std::string *code_ptr) {
154 std::string &code = *code_ptr;
155
156 GenReceiver(struct_def, code_ptr);
157 code += MakeCamel(NormalizedName(field)) + "Length()\n";
158 code += OffsetPrefix(field);
159 code +=
160 std::string(Indent) + Indent + "return " + SelfData + ":VectorLen(o)\n";
161 code += std::string(Indent) + End;
162 code += std::string(Indent) + "return 0\n";
163 code += EndFunc;
164 }
165
166 // Get the value of a struct's scalar.
167 void GetScalarFieldOfStruct(const StructDef &struct_def,
168 const FieldDef &field, std::string *code_ptr) {
169 std::string &code = *code_ptr;
170 std::string getter = GenGetter(field.value.type);
171 GenReceiver(struct_def, code_ptr);
172 code += MakeCamel(NormalizedName(field));
173 code += "()\n";
174 code += std::string(Indent) + "return " + getter;
175 code += std::string(SelfDataPos) + " + " + NumToString(field.value.offset) +
176 ")\n";
177 code += EndFunc;
178 }
179
180 // Get the value of a table's scalar.
181 void GetScalarFieldOfTable(const StructDef &struct_def, const FieldDef &field,
182 std::string *code_ptr) {
183 std::string &code = *code_ptr;
184 std::string getter = GenGetter(field.value.type);
185 GenReceiver(struct_def, code_ptr);
186 code += MakeCamel(NormalizedName(field));
187 code += "()\n";
188 code += OffsetPrefix(field);
189 getter += std::string("o + ") + SelfDataPos + ")";
190 auto is_bool = field.value.type.base_type == BASE_TYPE_BOOL;
191 if (is_bool) { getter = "(" + getter + " ~= 0)"; }
192 code += std::string(Indent) + Indent + "return " + getter + "\n";
193 code += std::string(Indent) + End;
194 std::string default_value;
195 if (is_bool) {
196 default_value = field.value.constant == "0" ? "false" : "true";
197 } else {
198 default_value = field.value.constant;
199 }
200 code += std::string(Indent) + "return " + default_value + "\n";
201 code += EndFunc;
202 }
203
204 // Get a struct by initializing an existing struct.
205 // Specific to Struct.
206 void GetStructFieldOfStruct(const StructDef &struct_def,
207 const FieldDef &field, std::string *code_ptr) {
208 std::string &code = *code_ptr;
209 GenReceiver(struct_def, code_ptr);
210 code += MakeCamel(NormalizedName(field));
211 code += "(obj)\n";
212 code += std::string(Indent) + "obj:Init(" + SelfDataBytes + ", " +
213 SelfDataPos + " + ";
214 code += NumToString(field.value.offset) + ")\n";
215 code += std::string(Indent) + "return obj\n";
216 code += EndFunc;
217 }
218
219 // Get a struct by initializing an existing struct.
220 // Specific to Table.
221 void GetStructFieldOfTable(const StructDef &struct_def, const FieldDef &field,
222 std::string *code_ptr) {
223 std::string &code = *code_ptr;
224 GenReceiver(struct_def, code_ptr);
225 code += MakeCamel(NormalizedName(field));
226 code += "()\n";
227 code += OffsetPrefix(field);
228 if (field.value.type.struct_def->fixed) {
229 code +=
230 std::string(Indent) + Indent + "local x = o + " + SelfDataPos + "\n";
231 } else {
232 code += std::string(Indent) + Indent + "local x = " + SelfData +
233 ":Indirect(o + " + SelfDataPos + ")\n";
234 }
235 code += std::string(Indent) + Indent + "local obj = require('" +
236 TypeNameWithNamespace(field) + "').New()\n";
237 code +=
238 std::string(Indent) + Indent + "obj:Init(" + SelfDataBytes + ", x)\n";
239 code += std::string(Indent) + Indent + "return obj\n";
240 code += std::string(Indent) + End;
241 code += EndFunc;
242 }
243
244 // Get the value of a string.
245 void GetStringField(const StructDef &struct_def, const FieldDef &field,
246 std::string *code_ptr) {
247 std::string &code = *code_ptr;
248 GenReceiver(struct_def, code_ptr);
249 code += MakeCamel(NormalizedName(field));
250 code += "()\n";
251 code += OffsetPrefix(field);
252 code +=
253 std::string(Indent) + Indent + "return " + GenGetter(field.value.type);
254 code += std::string("o + ") + SelfDataPos + ")\n";
255 code += std::string(Indent) + End;
256 code += EndFunc;
257 }
258
259 // Get the value of a union from an object.
260 void GetUnionField(const StructDef &struct_def, const FieldDef &field,
261 std::string *code_ptr) {
262 std::string &code = *code_ptr;
263 GenReceiver(struct_def, code_ptr);
264 code += MakeCamel(NormalizedName(field)) + "()\n";
265 code += OffsetPrefix(field);
266
267 // TODO(rw): this works and is not the good way to it:
268 // bool is_native_table = TypeName(field) == "*flatbuffers.Table";
269 // if (is_native_table) {
270 // code += std::string(Indent) + Indent + "from flatbuffers.table import
271 // Table\n";
272 //} else {
273 // code += std::string(Indent) + Indent +
274 // code += "from ." + TypeName(field) + " import " + TypeName(field) +
275 // "\n";
276 //}
277 code +=
278 std::string(Indent) + Indent +
279 "local obj = "
280 "flatbuffers.view.New(require('flatbuffers.binaryarray').New(0), 0)\n";
281 code += std::string(Indent) + Indent + GenGetter(field.value.type) +
282 "obj, o)\n";
283 code += std::string(Indent) + Indent + "return obj\n";
284 code += std::string(Indent) + End;
285 code += EndFunc;
286 }
287
288 // Get the value of a vector's struct member.
289 void GetMemberOfVectorOfStruct(const StructDef &struct_def,
290 const FieldDef &field, std::string *code_ptr) {
291 std::string &code = *code_ptr;
292 auto vectortype = field.value.type.VectorType();
293
294 GenReceiver(struct_def, code_ptr);
295 code += MakeCamel(NormalizedName(field));
296 code += "(j)\n";
297 code += OffsetPrefix(field);
298 code +=
299 std::string(Indent) + Indent + "local x = " + SelfData + ":Vector(o)\n";
300 code += std::string(Indent) + Indent + "x = x + ((j-1) * ";
301 code += NumToString(InlineSize(vectortype)) + ")\n";
302 if (!(vectortype.struct_def->fixed)) {
303 code +=
304 std::string(Indent) + Indent + "x = " + SelfData + ":Indirect(x)\n";
305 }
306 code += std::string(Indent) + Indent + "local obj = require('" +
307 TypeNameWithNamespace(field) + "').New()\n";
308 code +=
309 std::string(Indent) + Indent + "obj:Init(" + SelfDataBytes + ", x)\n";
310 code += std::string(Indent) + Indent + "return obj\n";
311 code += std::string(Indent) + End;
312 code += EndFunc;
313 }
314
315 // Get the value of a vector's non-struct member. Uses a named return
316 // argument to conveniently set the zero value for the result.
317 void GetMemberOfVectorOfNonStruct(const StructDef &struct_def,
318 const FieldDef &field,
319 std::string *code_ptr) {
320 std::string &code = *code_ptr;
321 auto vectortype = field.value.type.VectorType();
322
323 GenReceiver(struct_def, code_ptr);
324 code += MakeCamel(NormalizedName(field));
325 code += "(j)\n";
326 code += OffsetPrefix(field);
327 code +=
328 std::string(Indent) + Indent + "local a = " + SelfData + ":Vector(o)\n";
329 code += std::string(Indent) + Indent;
330 code += "return " + GenGetter(field.value.type);
331 code += "a + ((j-1) * ";
332 code += NumToString(InlineSize(vectortype)) + "))\n";
333 code += std::string(Indent) + End;
334 if (IsString(vectortype)) {
335 code += std::string(Indent) + "return ''\n";
336 } else {
337 code += std::string(Indent) + "return 0\n";
338 }
339 code += EndFunc;
340 }
341
342 // Access a byte/ubyte vector as a string
343 void AccessByteVectorAsString(const StructDef &struct_def,
344 const FieldDef &field, std::string *code_ptr) {
345 std::string &code = *code_ptr;
346 GenReceiver(struct_def, code_ptr);
347 code += MakeCamel(NormalizedName(field));
348 code += "AsString(start, stop)\n";
349 code += std::string(Indent) + "return " + SelfData + ":VectorAsString(" +
350 NumToString(field.value.offset) + ", start, stop)\n";
351 code += EndFunc;
352 }
353
354 // Begin the creator function signature.
355 void BeginBuilderArgs(const StructDef &struct_def, std::string *code_ptr) {
356 std::string &code = *code_ptr;
357
358 code += "function " + NormalizedName(struct_def) + ".Create" +
359 NormalizedName(struct_def);
360 code += "(builder";
361 }
362
363 // Recursively generate arguments for a constructor, to deal with nested
364 // structs.
365 void StructBuilderArgs(const StructDef &struct_def, const char *nameprefix,
366 std::string *code_ptr) {
367 for (auto it = struct_def.fields.vec.begin();
368 it != struct_def.fields.vec.end(); ++it) {
369 auto &field = **it;
370 if (IsStruct(field.value.type)) {
371 // Generate arguments for a struct inside a struct. To ensure names
372 // don't clash, and to make it obvious these arguments are constructing
373 // a nested struct, prefix the name with the field name.
374 StructBuilderArgs(*field.value.type.struct_def,
375 (nameprefix + (NormalizedName(field) + "_")).c_str(),
376 code_ptr);
377 } else {
378 std::string &code = *code_ptr;
379 code += std::string(", ") + nameprefix;
380 code += MakeCamel(NormalizedName(field), false);
381 }
382 }
383 }
384
385 // End the creator function signature.
386 void EndBuilderArgs(std::string *code_ptr) {
387 std::string &code = *code_ptr;
388 code += ")\n";
389 }
390
391 // Recursively generate struct construction statements and instert manual
392 // padding.
393 void StructBuilderBody(const StructDef &struct_def, const char *nameprefix,
394 std::string *code_ptr) {
395 std::string &code = *code_ptr;
396 code += std::string(Indent) + "builder:Prep(" +
397 NumToString(struct_def.minalign) + ", ";
398 code += NumToString(struct_def.bytesize) + ")\n";
399 for (auto it = struct_def.fields.vec.rbegin();
400 it != struct_def.fields.vec.rend(); ++it) {
401 auto &field = **it;
402 if (field.padding)
403 code += std::string(Indent) + "builder:Pad(" +
404 NumToString(field.padding) + ")\n";
405 if (IsStruct(field.value.type)) {
406 StructBuilderBody(*field.value.type.struct_def,
407 (nameprefix + (NormalizedName(field) + "_")).c_str(),
408 code_ptr);
409 } else {
410 code +=
411 std::string(Indent) + "builder:Prepend" + GenMethod(field) + "(";
412 code += nameprefix + MakeCamel(NormalizedName(field), false) + ")\n";
413 }
414 }
415 }
416
417 void EndBuilderBody(std::string *code_ptr) {
418 std::string &code = *code_ptr;
419 code += std::string(Indent) + "return builder:Offset()\n";
420 code += EndFunc;
421 }
422
423 // Get the value of a table's starting offset.
424 void GetStartOfTable(const StructDef &struct_def, std::string *code_ptr) {
425 std::string &code = *code_ptr;
426 code += "function " + NormalizedName(struct_def) + ".Start";
427 code += "(builder) ";
428 code += "builder:StartObject(";
429 code += NumToString(struct_def.fields.vec.size());
430 code += ") end\n";
431 }
432
433 // Set the value of a table's field.
434 void BuildFieldOfTable(const StructDef &struct_def, const FieldDef &field,
435 const size_t offset, std::string *code_ptr) {
436 std::string &code = *code_ptr;
437 code += "function " + NormalizedName(struct_def) + ".Add" +
438 MakeCamel(NormalizedName(field));
439 code += "(builder, ";
440 code += MakeCamel(NormalizedName(field), false);
441 code += ") ";
442 code += "builder:Prepend";
443 code += GenMethod(field) + "Slot(";
444 code += NumToString(offset) + ", ";
445 // todo: i don't need to cast in Lua, but am I missing something?
446 // if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
447 // code += "flatbuffers.N.UOffsetTFlags.py_type";
448 // code += "(";
449 // code += MakeCamel(NormalizedName(field), false) + ")";
450 // } else {
451 code += MakeCamel(NormalizedName(field), false);
452 // }
453 code += ", " + field.value.constant;
454 code += ") end\n";
455 }
456
457 // Set the value of one of the members of a table's vector.
458 void BuildVectorOfTable(const StructDef &struct_def, const FieldDef &field,
459 std::string *code_ptr) {
460 std::string &code = *code_ptr;
461 code += "function " + NormalizedName(struct_def) + ".Start";
462 code += MakeCamel(NormalizedName(field));
463 code += "Vector(builder, numElems) return builder:StartVector(";
464 auto vector_type = field.value.type.VectorType();
465 auto alignment = InlineAlignment(vector_type);
466 auto elem_size = InlineSize(vector_type);
467 code += NumToString(elem_size);
468 code += ", numElems, " + NumToString(alignment);
469 code += ") end\n";
470 }
471
472 // Get the offset of the end of a table.
473 void GetEndOffsetOnTable(const StructDef &struct_def, std::string *code_ptr) {
474 std::string &code = *code_ptr;
475 code += "function " + NormalizedName(struct_def) + ".End";
476 code += "(builder) ";
477 code += "return builder:EndObject() end\n";
478 }
479
480 // Generate the receiver for function signatures.
481 void GenReceiver(const StructDef &struct_def, std::string *code_ptr) {
482 std::string &code = *code_ptr;
483 code += "function " + NormalizedMetaName(struct_def) + ":";
484 }
485
486 // Generate a struct field, conditioned on its child type(s).
487 void GenStructAccessor(const StructDef &struct_def, const FieldDef &field,
488 std::string *code_ptr) {
489 GenComment(field.doc_comment, code_ptr, &def_comment);
490 if (IsScalar(field.value.type.base_type)) {
491 if (struct_def.fixed) {
492 GetScalarFieldOfStruct(struct_def, field, code_ptr);
493 } else {
494 GetScalarFieldOfTable(struct_def, field, code_ptr);
495 }
496 } else {
497 switch (field.value.type.base_type) {
498 case BASE_TYPE_STRUCT:
499 if (struct_def.fixed) {
500 GetStructFieldOfStruct(struct_def, field, code_ptr);
501 } else {
502 GetStructFieldOfTable(struct_def, field, code_ptr);
503 }
504 break;
505 case BASE_TYPE_STRING:
506 GetStringField(struct_def, field, code_ptr);
507 break;
508 case BASE_TYPE_VECTOR: {
509 auto vectortype = field.value.type.VectorType();
510 if (vectortype.base_type == BASE_TYPE_STRUCT) {
511 GetMemberOfVectorOfStruct(struct_def, field, code_ptr);
512 } else {
513 GetMemberOfVectorOfNonStruct(struct_def, field, code_ptr);
514 if (vectortype.base_type == BASE_TYPE_CHAR ||
515 vectortype.base_type == BASE_TYPE_UCHAR) {
516 AccessByteVectorAsString(struct_def, field, code_ptr);
517 }
518 }
519 break;
520 }
521 case BASE_TYPE_UNION: GetUnionField(struct_def, field, code_ptr); break;
522 default: FLATBUFFERS_ASSERT(0);
523 }
524 }
525 if (IsVector(field.value.type)) {
526 GetVectorLen(struct_def, field, code_ptr);
527 }
528 }
529
530 // Generate table constructors, conditioned on its members' types.
531 void GenTableBuilders(const StructDef &struct_def, std::string *code_ptr) {
532 GetStartOfTable(struct_def, code_ptr);
533
534 for (auto it = struct_def.fields.vec.begin();
535 it != struct_def.fields.vec.end(); ++it) {
536 auto &field = **it;
537 if (field.deprecated) continue;
538
539 auto offset = it - struct_def.fields.vec.begin();
540 BuildFieldOfTable(struct_def, field, offset, code_ptr);
541 if (IsVector(field.value.type)) {
542 BuildVectorOfTable(struct_def, field, code_ptr);
543 }
544 }
545
546 GetEndOffsetOnTable(struct_def, code_ptr);
547 }
548
549 // Generate struct or table methods.
550 void GenStruct(const StructDef &struct_def, std::string *code_ptr) {
551 if (struct_def.generated) return;
552
553 GenComment(struct_def.doc_comment, code_ptr, &def_comment);
554 BeginClass(struct_def, code_ptr);
555
556 GenerateNewObjectPrototype(struct_def, code_ptr);
557
558 if (!struct_def.fixed) {
559 // Generate a special accessor for the table that has been declared as
560 // the root type.
561 NewRootTypeFromBuffer(struct_def, code_ptr);
562 }
563
564 // Generate the Init method that sets the field in a pre-existing
565 // accessor object. This is to allow object reuse.
566 InitializeExisting(struct_def, code_ptr);
567 for (auto it = struct_def.fields.vec.begin();
568 it != struct_def.fields.vec.end(); ++it) {
569 auto &field = **it;
570 if (field.deprecated) continue;
571
572 GenStructAccessor(struct_def, field, code_ptr);
573 }
574
575 if (struct_def.fixed) {
576 // create a struct constructor function
577 GenStructBuilder(struct_def, code_ptr);
578 } else {
579 // Create a set of functions that allow table construction.
580 GenTableBuilders(struct_def, code_ptr);
581 }
582 }
583
584 // Generate enum declarations.
585 void GenEnum(const EnumDef &enum_def, std::string *code_ptr) {
586 if (enum_def.generated) return;
587
588 GenComment(enum_def.doc_comment, code_ptr, &def_comment);
589 BeginEnum(NormalizedName(enum_def), code_ptr);
590 for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
591 auto &ev = **it;
592 GenComment(ev.doc_comment, code_ptr, &def_comment, Indent);
593 EnumMember(enum_def, ev, code_ptr);
594 }
595 EndEnum(code_ptr);
596 }
597
598 // Returns the function name that is able to read a value of the given type.
599 std::string GenGetter(const Type &type) {
600 switch (type.base_type) {
601 case BASE_TYPE_STRING: return std::string(SelfData) + ":String(";
602 case BASE_TYPE_UNION: return std::string(SelfData) + ":Union(";
603 case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());
604 default:
605 return std::string(SelfData) + ":Get(flatbuffers.N." +
606 MakeCamel(GenTypeGet(type)) + ", ";
607 }
608 }
609
610 // Returns the method name for use with add/put calls.
611 std::string GenMethod(const FieldDef &field) {
612 return IsScalar(field.value.type.base_type)
613 ? MakeCamel(GenTypeBasic(field.value.type))
614 : (IsStruct(field.value.type) ? "Struct" : "UOffsetTRelative");
615 }
616
617 std::string GenTypeBasic(const Type &type) {
618 // clang-format off
619 static const char *ctypename[] = {
620 #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
621 CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, ...) \
622 #PTYPE,
623 FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
624 #undef FLATBUFFERS_TD
625 };
626 // clang-format on
627 return ctypename[type.base_type];
628 }
629
630 std::string GenTypePointer(const Type &type) {
631 switch (type.base_type) {
632 case BASE_TYPE_STRING: return "string";
633 case BASE_TYPE_VECTOR: return GenTypeGet(type.VectorType());
634 case BASE_TYPE_STRUCT: return type.struct_def->name;
635 case BASE_TYPE_UNION:
636 // fall through
637 default: return "*flatbuffers.Table";
638 }
639 }
640
641 std::string GenTypeGet(const Type &type) {
642 return IsScalar(type.base_type) ? GenTypeBasic(type) : GenTypePointer(type);
643 }
644
645 std::string GetNamespace(const Type &type) {
646 return type.struct_def->defined_namespace->GetFullyQualifiedName(
647 type.struct_def->name);
648 }
649
650 std::string TypeName(const FieldDef &field) {
651 return GenTypeGet(field.value.type);
652 }
653
654 std::string TypeNameWithNamespace(const FieldDef &field) {
655 return GetNamespace(field.value.type);
656 }
657
658 // Create a struct with a builder and the struct's arguments.
659 void GenStructBuilder(const StructDef &struct_def, std::string *code_ptr) {
660 BeginBuilderArgs(struct_def, code_ptr);
661 StructBuilderArgs(struct_def, "", code_ptr);
662 EndBuilderArgs(code_ptr);
663
664 StructBuilderBody(struct_def, "", code_ptr);
665 EndBuilderBody(code_ptr);
666 }
667
668 bool generate() {
669 if (!generateEnums()) return false;
670 if (!generateStructs()) return false;
671 return true;
672 }
673
674 private:
675 bool generateEnums() {
676 for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
677 ++it) {
678 auto &enum_def = **it;
679 std::string enumcode;
680 GenEnum(enum_def, &enumcode);
681 if (!SaveType(enum_def, enumcode, false)) return false;
682 }
683 return true;
684 }
685
686 bool generateStructs() {
687 for (auto it = parser_.structs_.vec.begin();
688 it != parser_.structs_.vec.end(); ++it) {
689 auto &struct_def = **it;
690 std::string declcode;
691 GenStruct(struct_def, &declcode);
692 if (!SaveType(struct_def, declcode, true)) return false;
693 }
694 return true;
695 }
696
697 // Begin by declaring namespace and imports.
698 void BeginFile(const std::string &name_space_name, const bool needs_imports,
699 std::string *code_ptr) {
700 std::string &code = *code_ptr;
701 code += std::string(Comment) + FlatBuffersGeneratedWarning() + "\n\n";
702 code += std::string(Comment) + "namespace: " + name_space_name + "\n\n";
703 if (needs_imports) {
704 code += "local flatbuffers = require('flatbuffers')\n\n";
705 }
706 }
707
708 // Save out the generated code for a Lua Table type.
709 bool SaveType(const Definition &def, const std::string &classcode,
710 bool needs_imports) {
711 if (!classcode.length()) return true;
712
713 std::string namespace_dir = path_;
714 auto &namespaces = def.defined_namespace->components;
715 for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
716 if (it != namespaces.begin()) namespace_dir += kPathSeparator;
717 namespace_dir += *it;
718 // std::string init_py_filename = namespace_dir + "/__init__.py";
719 // SaveFile(init_py_filename.c_str(), "", false);
720 }
721
722 std::string code = "";
723 BeginFile(LastNamespacePart(*def.defined_namespace), needs_imports, &code);
724 code += classcode;
725 code += "\n";
726 code +=
727 "return " + NormalizedName(def) + " " + Comment + "return the module";
728 std::string filename =
729 NamespaceDir(*def.defined_namespace) + NormalizedName(def) + ".lua";
730 return SaveFile(filename.c_str(), code, false);
731 }
732
733 private:
734 std::unordered_set<std::string> keywords_;
735};
736
737} // namespace lua
738
739bool GenerateLua(const Parser &parser, const std::string &path,
740 const std::string &file_name) {
741 lua::LuaGenerator generator(parser, path, file_name);
742 return generator.generate();
743}
744
745} // namespace flatbuffers
746