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 <sstream>
20#include <string>
21
22#include "flatbuffers/code_generators.h"
23#include "flatbuffers/flatbuffers.h"
24#include "flatbuffers/idl.h"
25#include "flatbuffers/util.h"
26
27#ifdef _WIN32
28# include <direct.h>
29# define PATH_SEPARATOR "\\"
30# define mkdir(n, m) _mkdir(n)
31#else
32# include <sys/stat.h>
33# define PATH_SEPARATOR "/"
34#endif
35
36namespace flatbuffers {
37
38static std::string GeneratedFileName(const std::string &path,
39 const std::string &file_name) {
40 return path + file_name + "_generated.go";
41}
42
43namespace go {
44
45// see https://golang.org/ref/spec#Keywords
46static const char * const g_golang_keywords[] = {
47 "break", "default", "func", "interface", "select", "case", "defer",
48 "go", "map", "struct", "chan", "else", "goto", "package",
49 "switch", "const", "fallthrough", "if", "range", "type", "continue",
50 "for", "import", "return", "var",
51};
52
53static std::string GoIdentity(const std::string &name) {
54 for (size_t i = 0;
55 i < sizeof(g_golang_keywords) / sizeof(g_golang_keywords[0]); i++) {
56 if (name == g_golang_keywords[i]) { return MakeCamel(name + "_", false); }
57 }
58
59 return MakeCamel(name, false);
60}
61
62class GoGenerator : public BaseGenerator {
63 public:
64 GoGenerator(const Parser &parser, const std::string &path,
65 const std::string &file_name, const std::string &go_namespace)
66 : BaseGenerator(parser, path, file_name, "" /* not used*/,
67 "" /* not used */),
68 cur_name_space_(nullptr) {
69 std::istringstream iss(go_namespace);
70 std::string component;
71 while (std::getline(iss, component, '.')) {
72 go_namespace_.components.push_back(component);
73 }
74 }
75
76 bool generate() {
77 std::string one_file_code;
78 for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
79 ++it) {
80 tracked_imported_namespaces_.clear();
81 std::string enumcode;
82 GenEnum(**it, &enumcode);
83 if (parser_.opts.one_file) {
84 one_file_code += enumcode;
85 } else {
86 if (!SaveType(**it, enumcode, false)) return false;
87 }
88 }
89
90 for (auto it = parser_.structs_.vec.begin();
91 it != parser_.structs_.vec.end(); ++it) {
92 tracked_imported_namespaces_.clear();
93 std::string declcode;
94 GenStruct(**it, &declcode);
95 if (parser_.opts.one_file) {
96 one_file_code += declcode;
97 } else {
98 if (!SaveType(**it, declcode, true)) return false;
99 }
100 }
101
102 if (parser_.opts.one_file) {
103 std::string code = "";
104 BeginFile(LastNamespacePart(go_namespace_), true, &code);
105 code += one_file_code;
106 const std::string filename = GeneratedFileName(path_, file_name_);
107 return SaveFile(filename.c_str(), code, false);
108 }
109
110 return true;
111 }
112
113 private:
114 Namespace go_namespace_;
115 Namespace *cur_name_space_;
116 std::set<const Namespace*> tracked_imported_namespaces_;
117
118 // Most field accessors need to retrieve and test the field offset first,
119 // this is the prefix code for that.
120 std::string OffsetPrefix(const FieldDef &field) {
121 return "{\n\to := flatbuffers.UOffsetT(rcv._tab.Offset(" +
122 NumToString(field.value.offset) + "))\n\tif o != 0 {\n";
123 }
124
125 // Begin a class declaration.
126 void BeginClass(const StructDef &struct_def, std::string *code_ptr) {
127 std::string &code = *code_ptr;
128
129 code += "type " + struct_def.name + " struct {\n\t";
130
131 // _ is reserved in flatbuffers field names, so no chance of name conflict:
132 code += "_tab ";
133 code += struct_def.fixed ? "flatbuffers.Struct" : "flatbuffers.Table";
134 code += "\n}\n\n";
135 }
136
137 // Construct the name of the type alias for this enum.
138 std::string GetEnumTypeName(const EnumDef &enum_def) {
139 return WrapInNameSpaceAndTrack(cur_name_space_, GoIdentity(enum_def.name));
140 }
141
142 // Create a type for the enum values.
143 void GenEnumType(const EnumDef &enum_def, std::string *code_ptr) {
144 std::string &code = *code_ptr;
145 code += "type " + GetEnumTypeName(enum_def) + " = ";
146 code += GenTypeBasic(enum_def.underlying_type) + "\n";
147 }
148
149 // Begin enum code with a class declaration.
150 void BeginEnum(std::string *code_ptr) {
151 std::string &code = *code_ptr;
152 code += "const (\n";
153 }
154
155 // A single enum member.
156 void EnumMember(const EnumDef &enum_def, const EnumVal &ev,
157 std::string *code_ptr) {
158 std::string &code = *code_ptr;
159 code += "\t";
160 code += enum_def.name;
161 code += ev.name;
162 code += " ";
163 code += GetEnumTypeName(enum_def);
164 code += " = ";
165 code += NumToString(ev.value) + "\n";
166 }
167
168 // End enum code.
169 void EndEnum(std::string *code_ptr) {
170 std::string &code = *code_ptr;
171 code += ")\n\n";
172 }
173
174 // Begin enum name code.
175 void BeginEnumNames(const EnumDef &enum_def, std::string *code_ptr) {
176 std::string &code = *code_ptr;
177 code += "var EnumNames";
178 code += enum_def.name;
179 code += " = map[" + GetEnumTypeName(enum_def) + "]string{\n";
180 }
181
182 // A single enum name member.
183 void EnumNameMember(const EnumDef &enum_def, const EnumVal ev,
184 std::string *code_ptr) {
185 std::string &code = *code_ptr;
186 code += "\t";
187 code += enum_def.name;
188 code += ev.name;
189 code += ":\"";
190 code += ev.name;
191 code += "\",\n";
192 }
193
194 // End enum name code.
195 void EndEnumNames(std::string *code_ptr) {
196 std::string &code = *code_ptr;
197 code += "}\n\n";
198 }
199
200 // Initialize a new struct or table from existing data.
201 void NewRootTypeFromBuffer(const StructDef &struct_def,
202 std::string *code_ptr) {
203 std::string &code = *code_ptr;
204
205 code += "func GetRootAs";
206 code += struct_def.name;
207 code += "(buf []byte, offset flatbuffers.UOffsetT) ";
208 code += "*" + struct_def.name + "";
209 code += " {\n";
210 code += "\tn := flatbuffers.GetUOffsetT(buf[offset:])\n";
211 code += "\tx := &" + struct_def.name + "{}\n";
212 code += "\tx.Init(buf, n+offset)\n";
213 code += "\treturn x\n";
214 code += "}\n\n";
215 }
216
217 // Initialize an existing object with other data, to avoid an allocation.
218 void InitializeExisting(const StructDef &struct_def, std::string *code_ptr) {
219 std::string &code = *code_ptr;
220
221 GenReceiver(struct_def, code_ptr);
222 code += " Init(buf []byte, i flatbuffers.UOffsetT) ";
223 code += "{\n";
224 code += "\trcv._tab.Bytes = buf\n";
225 code += "\trcv._tab.Pos = i\n";
226 code += "}\n\n";
227 }
228
229 // Implement the table accessor
230 void GenTableAccessor(const StructDef &struct_def, std::string *code_ptr) {
231 std::string &code = *code_ptr;
232
233 GenReceiver(struct_def, code_ptr);
234 code += " Table() flatbuffers.Table ";
235 code += "{\n";
236
237 if (struct_def.fixed) {
238 code += "\treturn rcv._tab.Table\n";
239 } else {
240 code += "\treturn rcv._tab\n";
241 }
242 code += "}\n\n";
243 }
244
245 // Get the length of a vector.
246 void GetVectorLen(const StructDef &struct_def, const FieldDef &field,
247 std::string *code_ptr) {
248 std::string &code = *code_ptr;
249
250 GenReceiver(struct_def, code_ptr);
251 code += " " + MakeCamel(field.name) + "Length(";
252 code += ") int " + OffsetPrefix(field);
253 code += "\t\treturn rcv._tab.VectorLen(o)\n\t}\n";
254 code += "\treturn 0\n}\n\n";
255 }
256
257 // Get a [ubyte] vector as a byte slice.
258 void GetUByteSlice(const StructDef &struct_def, const FieldDef &field,
259 std::string *code_ptr) {
260 std::string &code = *code_ptr;
261
262 GenReceiver(struct_def, code_ptr);
263 code += " " + MakeCamel(field.name) + "Bytes(";
264 code += ") []byte " + OffsetPrefix(field);
265 code += "\t\treturn rcv._tab.ByteVector(o + rcv._tab.Pos)\n\t}\n";
266 code += "\treturn nil\n}\n\n";
267 }
268
269 // Get the value of a struct's scalar.
270 void GetScalarFieldOfStruct(const StructDef &struct_def,
271 const FieldDef &field,
272 std::string *code_ptr) {
273 std::string &code = *code_ptr;
274 std::string getter = GenGetter(field.value.type);
275 GenReceiver(struct_def, code_ptr);
276 code += " " + MakeCamel(field.name);
277 code += "() " + TypeName(field) + " {\n";
278 code += "\treturn " + getter;
279 code += "(rcv._tab.Pos + flatbuffers.UOffsetT(";
280 code += NumToString(field.value.offset) + "))\n}\n";
281 }
282
283 // Get the value of a table's scalar.
284 void GetScalarFieldOfTable(const StructDef &struct_def,
285 const FieldDef &field,
286 std::string *code_ptr) {
287 std::string &code = *code_ptr;
288 std::string getter = GenGetter(field.value.type);
289 GenReceiver(struct_def, code_ptr);
290 code += " " + MakeCamel(field.name);
291 code += "() " + TypeName(field) + " ";
292 code += OffsetPrefix(field) + "\t\treturn " + getter;
293 code += "(o + rcv._tab.Pos)\n\t}\n";
294 code += "\treturn " + GenConstant(field) + "\n";
295 code += "}\n\n";
296 }
297
298 // Get a struct by initializing an existing struct.
299 // Specific to Struct.
300 void GetStructFieldOfStruct(const StructDef &struct_def,
301 const FieldDef &field,
302 std::string *code_ptr) {
303 std::string &code = *code_ptr;
304 GenReceiver(struct_def, code_ptr);
305 code += " " + MakeCamel(field.name);
306 code += "(obj *" + TypeName(field);
307 code += ") *" + TypeName(field);
308 code += " {\n";
309 code += "\tif obj == nil {\n";
310 code += "\t\tobj = new(" + TypeName(field) + ")\n";
311 code += "\t}\n";
312 code += "\tobj.Init(rcv._tab.Bytes, rcv._tab.Pos+";
313 code += NumToString(field.value.offset) + ")";
314 code += "\n\treturn obj\n";
315 code += "}\n";
316 }
317
318 // Get a struct by initializing an existing struct.
319 // Specific to Table.
320 void GetStructFieldOfTable(const StructDef &struct_def,
321 const FieldDef &field,
322 std::string *code_ptr) {
323 std::string &code = *code_ptr;
324 GenReceiver(struct_def, code_ptr);
325 code += " " + MakeCamel(field.name);
326 code += "(obj *";
327 code += TypeName(field);
328 code += ") *" + TypeName(field) + " " + OffsetPrefix(field);
329 if (field.value.type.struct_def->fixed) {
330 code += "\t\tx := o + rcv._tab.Pos\n";
331 } else {
332 code += "\t\tx := rcv._tab.Indirect(o + rcv._tab.Pos)\n";
333 }
334 code += "\t\tif obj == nil {\n";
335 code += "\t\t\tobj = new(" + TypeName(field) + ")\n";
336 code += "\t\t}\n";
337 code += "\t\tobj.Init(rcv._tab.Bytes, x)\n";
338 code += "\t\treturn obj\n\t}\n\treturn nil\n";
339 code += "}\n\n";
340 }
341
342 // Get the value of a string.
343 void GetStringField(const StructDef &struct_def,
344 const FieldDef &field,
345 std::string *code_ptr) {
346 std::string &code = *code_ptr;
347 GenReceiver(struct_def, code_ptr);
348 code += " " + MakeCamel(field.name);
349 code += "() " + TypeName(field) + " ";
350 code += OffsetPrefix(field) + "\t\treturn " + GenGetter(field.value.type);
351 code += "(o + rcv._tab.Pos)\n\t}\n\treturn nil\n";
352 code += "}\n\n";
353 }
354
355 // Get the value of a union from an object.
356 void GetUnionField(const StructDef &struct_def, const FieldDef &field,
357 std::string *code_ptr) {
358 std::string &code = *code_ptr;
359 GenReceiver(struct_def, code_ptr);
360 code += " " + MakeCamel(field.name) + "(";
361 code += "obj " + TypeName(field) + ") bool ";
362 code += OffsetPrefix(field);
363 code += "\t\t" + GenGetter(field.value.type);
364 code += "(obj, o)\n\t\treturn true\n\t}\n";
365 code += "\treturn false\n";
366 code += "}\n\n";
367 }
368
369 // Get the value of a vector's struct member.
370 void GetMemberOfVectorOfStruct(const StructDef &struct_def,
371 const FieldDef &field,
372 std::string *code_ptr) {
373 std::string &code = *code_ptr;
374 auto vectortype = field.value.type.VectorType();
375
376 GenReceiver(struct_def, code_ptr);
377 code += " " + MakeCamel(field.name);
378 code += "(obj *" + TypeName(field);
379 code += ", j int) bool " + OffsetPrefix(field);
380 code += "\t\tx := rcv._tab.Vector(o)\n";
381 code += "\t\tx += flatbuffers.UOffsetT(j) * ";
382 code += NumToString(InlineSize(vectortype)) + "\n";
383 if (!(vectortype.struct_def->fixed)) {
384 code += "\t\tx = rcv._tab.Indirect(x)\n";
385 }
386 code += "\t\tobj.Init(rcv._tab.Bytes, x)\n";
387 code += "\t\treturn true\n\t}\n";
388 code += "\treturn false\n";
389 code += "}\n\n";
390 }
391
392 // Get the value of a vector's non-struct member. Uses a named return
393 // argument to conveniently set the zero value for the result.
394 void GetMemberOfVectorOfNonStruct(const StructDef &struct_def,
395 const FieldDef &field,
396 std::string *code_ptr) {
397 std::string &code = *code_ptr;
398 auto vectortype = field.value.type.VectorType();
399
400 GenReceiver(struct_def, code_ptr);
401 code += " " + MakeCamel(field.name);
402 code += "(j int) " + TypeName(field) + " ";
403 code += OffsetPrefix(field);
404 code += "\t\ta := rcv._tab.Vector(o)\n";
405 code += "\t\treturn " + GenGetter(field.value.type) + "(";
406 code += "a + flatbuffers.UOffsetT(j*";
407 code += NumToString(InlineSize(vectortype)) + "))\n";
408 code += "\t}\n";
409 if (vectortype.base_type == BASE_TYPE_STRING) {
410 code += "\treturn nil\n";
411 } else if (vectortype.base_type == BASE_TYPE_BOOL) {
412 code += "\treturn false\n";
413 } else {
414 code += "\treturn 0\n";
415 }
416 code += "}\n\n";
417 }
418
419 // Begin the creator function signature.
420 void BeginBuilderArgs(const StructDef &struct_def, std::string *code_ptr) {
421 std::string &code = *code_ptr;
422
423 if (code.substr(code.length() - 2) != "\n\n") {
424 // a previous mutate has not put an extra new line
425 code += "\n";
426 }
427 code += "func Create" + struct_def.name;
428 code += "(builder *flatbuffers.Builder";
429 }
430
431 // Recursively generate arguments for a constructor, to deal with nested
432 // structs.
433 void StructBuilderArgs(const StructDef &struct_def, const char *nameprefix,
434 std::string *code_ptr) {
435 for (auto it = struct_def.fields.vec.begin();
436 it != struct_def.fields.vec.end(); ++it) {
437 auto &field = **it;
438 if (IsStruct(field.value.type)) {
439 // Generate arguments for a struct inside a struct. To ensure names
440 // don't clash, and to make it obvious these arguments are constructing
441 // a nested struct, prefix the name with the field name.
442 StructBuilderArgs(*field.value.type.struct_def,
443 (nameprefix + (field.name + "_")).c_str(), code_ptr);
444 } else {
445 std::string &code = *code_ptr;
446 code += std::string(", ") + nameprefix;
447 code += GoIdentity(field.name);
448 code += " " + GenTypeBasic(field.value.type);
449 }
450 }
451 }
452
453 // End the creator function signature.
454 void EndBuilderArgs(std::string *code_ptr) {
455 std::string &code = *code_ptr;
456 code += ") flatbuffers.UOffsetT {\n";
457 }
458
459 // Recursively generate struct construction statements and instert manual
460 // padding.
461 void StructBuilderBody(const StructDef &struct_def,
462 const char *nameprefix, std::string *code_ptr) {
463 std::string &code = *code_ptr;
464 code += "\tbuilder.Prep(" + NumToString(struct_def.minalign) + ", ";
465 code += NumToString(struct_def.bytesize) + ")\n";
466 for (auto it = struct_def.fields.vec.rbegin();
467 it != struct_def.fields.vec.rend(); ++it) {
468 auto &field = **it;
469 if (field.padding)
470 code += "\tbuilder.Pad(" + NumToString(field.padding) + ")\n";
471 if (IsStruct(field.value.type)) {
472 StructBuilderBody(*field.value.type.struct_def,
473 (nameprefix + (field.name + "_")).c_str(), code_ptr);
474 } else {
475 code += "\tbuilder.Prepend" + GenMethod(field) + "(";
476 code += nameprefix + GoIdentity(field.name) + ")\n";
477 }
478 }
479 }
480
481 void EndBuilderBody(std::string *code_ptr) {
482 std::string &code = *code_ptr;
483 code += "\treturn builder.Offset()\n";
484 code += "}\n";
485 }
486
487 // Get the value of a table's starting offset.
488 void GetStartOfTable(const StructDef &struct_def, std::string *code_ptr) {
489 std::string &code = *code_ptr;
490 code += "func " + struct_def.name + "Start";
491 code += "(builder *flatbuffers.Builder) {\n";
492 code += "\tbuilder.StartObject(";
493 code += NumToString(struct_def.fields.vec.size());
494 code += ")\n}\n";
495 }
496
497 // Set the value of a table's field.
498 void BuildFieldOfTable(const StructDef &struct_def, const FieldDef &field,
499 const size_t offset, std::string *code_ptr) {
500 std::string &code = *code_ptr;
501 code += "func " + struct_def.name + "Add" + MakeCamel(field.name);
502 code += "(builder *flatbuffers.Builder, ";
503 code += GoIdentity(field.name) + " ";
504 if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
505 code += "flatbuffers.UOffsetT";
506 } else {
507 code += GenTypeBasic(field.value.type);
508 }
509 code += ") {\n";
510 code += "\tbuilder.Prepend";
511 code += GenMethod(field) + "Slot(";
512 code += NumToString(offset) + ", ";
513 if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
514 code += "flatbuffers.UOffsetT";
515 code += "(";
516 code += GoIdentity(field.name) + ")";
517 } else {
518 code += GoIdentity(field.name);
519 }
520 code += ", " + GenConstant(field);
521 code += ")\n}\n";
522 }
523
524 // Set the value of one of the members of a table's vector.
525 void BuildVectorOfTable(const StructDef &struct_def,
526 const FieldDef &field, std::string *code_ptr) {
527 std::string &code = *code_ptr;
528 code += "func " + struct_def.name + "Start";
529 code += MakeCamel(field.name);
530 code += "Vector(builder *flatbuffers.Builder, numElems int) ";
531 code += "flatbuffers.UOffsetT {\n\treturn builder.StartVector(";
532 auto vector_type = field.value.type.VectorType();
533 auto alignment = InlineAlignment(vector_type);
534 auto elem_size = InlineSize(vector_type);
535 code += NumToString(elem_size);
536 code += ", numElems, " + NumToString(alignment);
537 code += ")\n}\n";
538 }
539
540 // Get the offset of the end of a table.
541 void GetEndOffsetOnTable(const StructDef &struct_def, std::string *code_ptr) {
542 std::string &code = *code_ptr;
543 code += "func " + struct_def.name + "End";
544 code += "(builder *flatbuffers.Builder) flatbuffers.UOffsetT ";
545 code += "{\n\treturn builder.EndObject()\n}\n";
546 }
547
548 // Generate the receiver for function signatures.
549 void GenReceiver(const StructDef &struct_def, std::string *code_ptr) {
550 std::string &code = *code_ptr;
551 code += "func (rcv *" + struct_def.name + ")";
552 }
553
554 // Generate a struct field getter, conditioned on its child type(s).
555 void GenStructAccessor(const StructDef &struct_def,
556 const FieldDef &field, std::string *code_ptr) {
557 GenComment(field.doc_comment, code_ptr, nullptr, "");
558 if (IsScalar(field.value.type.base_type)) {
559 if (struct_def.fixed) {
560 GetScalarFieldOfStruct(struct_def, field, code_ptr);
561 } else {
562 GetScalarFieldOfTable(struct_def, field, code_ptr);
563 }
564 } else {
565 switch (field.value.type.base_type) {
566 case BASE_TYPE_STRUCT:
567 if (struct_def.fixed) {
568 GetStructFieldOfStruct(struct_def, field, code_ptr);
569 } else {
570 GetStructFieldOfTable(struct_def, field, code_ptr);
571 }
572 break;
573 case BASE_TYPE_STRING: GetStringField(struct_def, field, code_ptr); break;
574 case BASE_TYPE_VECTOR: {
575 auto vectortype = field.value.type.VectorType();
576 if (vectortype.base_type == BASE_TYPE_STRUCT) {
577 GetMemberOfVectorOfStruct(struct_def, field, code_ptr);
578 } else {
579 GetMemberOfVectorOfNonStruct(struct_def, field, code_ptr);
580 }
581 break;
582 }
583 case BASE_TYPE_UNION: GetUnionField(struct_def, field, code_ptr); break;
584 default: FLATBUFFERS_ASSERT(0);
585 }
586 }
587 if (field.value.type.base_type == BASE_TYPE_VECTOR) {
588 GetVectorLen(struct_def, field, code_ptr);
589 if (field.value.type.element == BASE_TYPE_UCHAR) {
590 GetUByteSlice(struct_def, field, code_ptr);
591 }
592 }
593 }
594
595 // Mutate the value of a struct's scalar.
596 void MutateScalarFieldOfStruct(const StructDef &struct_def,
597 const FieldDef &field,
598 std::string *code_ptr) {
599 std::string &code = *code_ptr;
600 std::string type = MakeCamel(GenTypeBasic(field.value.type));
601 std::string setter = "rcv._tab.Mutate" + type;
602 GenReceiver(struct_def, code_ptr);
603 code += " Mutate" + MakeCamel(field.name);
604 code += "(n " + TypeName(field) + ") bool {\n\treturn " + setter;
605 code += "(rcv._tab.Pos+flatbuffers.UOffsetT(";
606 code += NumToString(field.value.offset) + "), n)\n}\n\n";
607 }
608
609 // Mutate the value of a table's scalar.
610 void MutateScalarFieldOfTable(const StructDef &struct_def,
611 const FieldDef &field,
612 std::string *code_ptr) {
613 std::string &code = *code_ptr;
614 std::string type = MakeCamel(GenTypeBasic(field.value.type));
615 std::string setter = "rcv._tab.Mutate" + type + "Slot";
616 GenReceiver(struct_def, code_ptr);
617 code += " Mutate" + MakeCamel(field.name);
618 code += "(n " + TypeName(field) + ") bool {\n\treturn ";
619 code += setter + "(" + NumToString(field.value.offset) + ", n)\n";
620 code += "}\n\n";
621 }
622
623 // Mutate an element of a vector of scalars.
624 void MutateElementOfVectorOfNonStruct(const StructDef &struct_def,
625 const FieldDef &field,
626 std::string *code_ptr) {
627 std::string &code = *code_ptr;
628 auto vectortype = field.value.type.VectorType();
629 std::string type = MakeCamel(GenTypeBasic(vectortype));
630 std::string setter = "rcv._tab.Mutate" + type;
631 GenReceiver(struct_def, code_ptr);
632 code += " Mutate" + MakeCamel(field.name);
633 code += "(j int, n " + TypeName(field) + ") bool ";
634 code += OffsetPrefix(field);
635 code += "\t\ta := rcv._tab.Vector(o)\n";
636 code += "\t\treturn " + setter + "(";
637 code += "a+flatbuffers.UOffsetT(j*";
638 code += NumToString(InlineSize(vectortype)) + "), n)\n";
639 code += "\t}\n";
640 code += "\treturn false\n";
641 code += "}\n\n";
642 }
643
644 // Generate a struct field setter, conditioned on its child type(s).
645 void GenStructMutator(const StructDef &struct_def, const FieldDef &field,
646 std::string *code_ptr) {
647 GenComment(field.doc_comment, code_ptr, nullptr, "");
648 if (IsScalar(field.value.type.base_type)) {
649 if (struct_def.fixed) {
650 MutateScalarFieldOfStruct(struct_def, field, code_ptr);
651 } else {
652 MutateScalarFieldOfTable(struct_def, field, code_ptr);
653 }
654 } else if (field.value.type.base_type == BASE_TYPE_VECTOR) {
655 if (IsScalar(field.value.type.element)) {
656 MutateElementOfVectorOfNonStruct(struct_def, field, code_ptr);
657 }
658 }
659 }
660
661 // Generate table constructors, conditioned on its members' types.
662 void GenTableBuilders(const StructDef &struct_def, std::string *code_ptr) {
663 GetStartOfTable(struct_def, code_ptr);
664
665 for (auto it = struct_def.fields.vec.begin();
666 it != struct_def.fields.vec.end(); ++it) {
667 auto &field = **it;
668 if (field.deprecated) continue;
669
670 auto offset = it - struct_def.fields.vec.begin();
671 BuildFieldOfTable(struct_def, field, offset, code_ptr);
672 if (field.value.type.base_type == BASE_TYPE_VECTOR) {
673 BuildVectorOfTable(struct_def, field, code_ptr);
674 }
675 }
676
677 GetEndOffsetOnTable(struct_def, code_ptr);
678 }
679
680 // Generate struct or table methods.
681 void GenStruct(const StructDef &struct_def, std::string *code_ptr) {
682 if (struct_def.generated) return;
683
684 cur_name_space_ = struct_def.defined_namespace;
685
686 GenComment(struct_def.doc_comment, code_ptr, nullptr);
687 BeginClass(struct_def, code_ptr);
688 if (!struct_def.fixed) {
689 // Generate a special accessor for the table that has been declared as
690 // the root type.
691 NewRootTypeFromBuffer(struct_def, code_ptr);
692 }
693 // Generate the Init method that sets the field in a pre-existing
694 // accessor object. This is to allow object reuse.
695 InitializeExisting(struct_def, code_ptr);
696 // Generate _tab accessor
697 GenTableAccessor(struct_def, code_ptr);
698
699 // Generate struct fields accessors
700 for (auto it = struct_def.fields.vec.begin();
701 it != struct_def.fields.vec.end(); ++it) {
702 auto &field = **it;
703 if (field.deprecated) continue;
704
705 GenStructAccessor(struct_def, field, code_ptr);
706 GenStructMutator(struct_def, field, code_ptr);
707 }
708
709 // Generate builders
710 if (struct_def.fixed) {
711 // create a struct constructor function
712 GenStructBuilder(struct_def, code_ptr);
713 } else {
714 // Create a set of functions that allow table construction.
715 GenTableBuilders(struct_def, code_ptr);
716 }
717 }
718
719 // Generate enum declarations.
720 void GenEnum(const EnumDef &enum_def, std::string *code_ptr) {
721 if (enum_def.generated) return;
722
723 cur_name_space_ = enum_def.defined_namespace;
724
725 GenComment(enum_def.doc_comment, code_ptr, nullptr);
726 GenEnumType(enum_def, code_ptr);
727 BeginEnum(code_ptr);
728 for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
729 auto &ev = **it;
730 GenComment(ev.doc_comment, code_ptr, nullptr, "\t");
731 EnumMember(enum_def, ev, code_ptr);
732 }
733 EndEnum(code_ptr);
734
735 BeginEnumNames(enum_def, code_ptr);
736 for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
737 auto &ev = **it;
738 EnumNameMember(enum_def, ev, code_ptr);
739 }
740 EndEnumNames(code_ptr);
741 }
742
743 // Returns the function name that is able to read a value of the given type.
744 std::string GenGetter(const Type &type) {
745 switch (type.base_type) {
746 case BASE_TYPE_STRING: return "rcv._tab.ByteVector";
747 case BASE_TYPE_UNION: return "rcv._tab.Union";
748 case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());
749 default: return "rcv._tab.Get" + MakeCamel(GenTypeBasic(type));
750 }
751 }
752
753 // Returns the method name for use with add/put calls.
754 std::string GenMethod(const FieldDef &field) {
755 return IsScalar(field.value.type.base_type)
756 ? MakeCamel(GenTypeBasic(field.value.type))
757 : (IsStruct(field.value.type) ? "Struct" : "UOffsetT");
758 }
759
760 std::string GenTypeBasic(const Type &type) {
761 static const char *ctypename[] = {
762 // clang-format off
763 #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
764 CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE) \
765 #GTYPE,
766 FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
767 #undef FLATBUFFERS_TD
768 // clang-format on
769 };
770 return ctypename[type.base_type];
771 }
772
773 std::string GenTypePointer(const Type &type) {
774 switch (type.base_type) {
775 case BASE_TYPE_STRING: return "[]byte";
776 case BASE_TYPE_VECTOR: return GenTypeGet(type.VectorType());
777 case BASE_TYPE_STRUCT: return WrapInNameSpaceAndTrack(*type.struct_def);
778 case BASE_TYPE_UNION:
779 // fall through
780 default: return "*flatbuffers.Table";
781 }
782 }
783
784 std::string GenTypeGet(const Type &type) {
785 if (type.enum_def != nullptr && !type.enum_def->is_union) {
786 return GetEnumTypeName(*type.enum_def);
787 }
788 return IsScalar(type.base_type) ? GenTypeBasic(type) : GenTypePointer(type);
789 }
790
791 std::string TypeName(const FieldDef &field) {
792 return GenTypeGet(field.value.type);
793 }
794
795 std::string GenConstant(const FieldDef &field) {
796 switch (field.value.type.base_type) {
797 case BASE_TYPE_BOOL: return field.value.constant == "0" ? "false" : "true";;
798 default: return field.value.constant;
799 }
800 }
801
802 // Create a struct with a builder and the struct's arguments.
803 void GenStructBuilder(const StructDef &struct_def, std::string *code_ptr) {
804 BeginBuilderArgs(struct_def, code_ptr);
805 StructBuilderArgs(struct_def, "", code_ptr);
806 EndBuilderArgs(code_ptr);
807
808 StructBuilderBody(struct_def, "", code_ptr);
809 EndBuilderBody(code_ptr);
810 }
811 // Begin by declaring namespace and imports.
812 void BeginFile(const std::string name_space_name, const bool needs_imports,
813 std::string *code_ptr) {
814 std::string &code = *code_ptr;
815 code = code + "// Code generated by the FlatBuffers compiler. DO NOT EDIT.\n\n";
816 code += "package " + name_space_name + "\n\n";
817 if (needs_imports) {
818 code += "import (\n";
819 if (!parser_.opts.go_import.empty()) {
820 code += "\tflatbuffers \"" + parser_.opts.go_import + "\"\n";
821 } else {
822 code += "\tflatbuffers \"github.com/google/flatbuffers/go\"\n";
823 }
824 if (tracked_imported_namespaces_.size() > 0) {
825 code += "\n";
826 for (auto it = tracked_imported_namespaces_.begin();
827 it != tracked_imported_namespaces_.end();
828 ++it) {
829 code += "\t" + NamespaceImportName(*it) + " \"" + \
830 NamespaceImportPath(*it) + "\"\n";
831 }
832 }
833 code += ")\n\n";
834 }
835 }
836
837 // Save out the generated code for a Go Table type.
838 bool SaveType(const Definition &def, const std::string &classcode,
839 bool needs_imports) {
840 if (!classcode.length()) return true;
841
842 Namespace &ns = go_namespace_.components.empty() ? *def.defined_namespace
843 : go_namespace_;
844 std::string code = "";
845 BeginFile(LastNamespacePart(ns), needs_imports, &code);
846 code += classcode;
847 std::string filename = NamespaceDir(ns) + def.name + ".go";
848 return SaveFile(filename.c_str(), code, false);
849 }
850
851 // Create the full name of the imported namespace (format: A__B__C).
852 std::string NamespaceImportName(const Namespace *ns) {
853 std::string s = "";
854 for (auto it = ns->components.begin(); it != ns->components.end(); ++it) {
855 if (s.size() == 0) {
856 s += *it;
857 } else {
858 s += "__" + *it;
859 }
860 }
861 return s;
862 }
863
864 // Create the full path for the imported namespace (format: A/B/C).
865 std::string NamespaceImportPath(const Namespace *ns) {
866 std::string s = "";
867 for (auto it = ns->components.begin(); it != ns->components.end(); ++it) {
868 if (s.size() == 0) {
869 s += *it;
870 } else {
871 s += "/" + *it;
872 }
873 }
874 return s;
875 }
876
877 // Ensure that a type is prefixed with its go package import name if it is
878 // used outside of its namespace.
879 std::string WrapInNameSpaceAndTrack(const Namespace *ns,
880 const std::string &name) {
881 if (CurrentNameSpace() == ns) return name;
882
883 tracked_imported_namespaces_.insert(ns);
884
885 std::string import_name = NamespaceImportName(ns);
886 return import_name + "." + name;
887 }
888
889 std::string WrapInNameSpaceAndTrack(const Definition &def) {
890 return WrapInNameSpaceAndTrack(def.defined_namespace, def.name);
891 }
892
893 const Namespace *CurrentNameSpace() const { return cur_name_space_; }
894};
895} // namespace go
896
897bool GenerateGo(const Parser &parser, const std::string &path,
898 const std::string &file_name) {
899 go::GoGenerator generator(parser, path, file_name, parser.opts.go_namespace);
900 return generator.generate();
901}
902
903} // namespace flatbuffers
904