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1 /*
2  * Copyright 2015 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 #include "flatbuffers/reflection.h"
18 #include "flatbuffers/util.h"
19 
20 // Helper functionality for reflection.
21 
22 namespace flatbuffers {
23 
GetAnyValueI(reflection::BaseType type,const uint8_t * data)24 int64_t GetAnyValueI(reflection::BaseType type, const uint8_t *data) {
25 # define FLATBUFFERS_GET(T) static_cast<int64_t>(ReadScalar<T>(data))
26   switch (type) {
27     case reflection::UType:
28     case reflection::Bool:
29     case reflection::UByte:  return FLATBUFFERS_GET(uint8_t);
30     case reflection::Byte:   return FLATBUFFERS_GET(int8_t);
31     case reflection::Short:  return FLATBUFFERS_GET(int16_t);
32     case reflection::UShort: return FLATBUFFERS_GET(uint16_t);
33     case reflection::Int:    return FLATBUFFERS_GET(int32_t);
34     case reflection::UInt:   return FLATBUFFERS_GET(uint32_t);
35     case reflection::Long:   return FLATBUFFERS_GET(int64_t);
36     case reflection::ULong:  return FLATBUFFERS_GET(uint64_t);
37     case reflection::Float:  return FLATBUFFERS_GET(float);
38     case reflection::Double: return FLATBUFFERS_GET(double);
39     case reflection::String: {
40       auto s = reinterpret_cast<const String *>(ReadScalar<uoffset_t>(data) +
41                                                 data);
42       return s ? StringToInt(s->c_str()) : 0;
43     }
44     default: return 0;  // Tables & vectors do not make sense.
45   }
46 # undef FLATBUFFERS_GET
47 }
48 
GetAnyValueF(reflection::BaseType type,const uint8_t * data)49 double GetAnyValueF(reflection::BaseType type, const uint8_t *data) {
50   switch (type) {
51     case reflection::Float:  return static_cast<double>(ReadScalar<float>(data));
52     case reflection::Double: return ReadScalar<double>(data);
53     case reflection::String: {
54       auto s = reinterpret_cast<const String *>(ReadScalar<uoffset_t>(data) +
55                                                 data);
56       return s ? strtod(s->c_str(), nullptr) : 0.0;
57     }
58     default: return static_cast<double>(GetAnyValueI(type, data));
59   }
60 }
61 
GetAnyValueS(reflection::BaseType type,const uint8_t * data,const reflection::Schema * schema,int type_index)62 std::string GetAnyValueS(reflection::BaseType type, const uint8_t *data,
63                          const reflection::Schema *schema, int type_index) {
64   switch (type) {
65     case reflection::Float:
66     case reflection::Double: return NumToString(GetAnyValueF(type, data));
67     case reflection::String: {
68       auto s = reinterpret_cast<const String *>(ReadScalar<uoffset_t>(data) +
69                                                 data);
70       return s ? s->c_str() : "";
71     }
72     case reflection::Obj:
73       if (schema) {
74         // Convert the table to a string. This is mostly for debugging purposes,
75         // and does NOT promise to be JSON compliant.
76         // Also prefixes the type.
77         auto &objectdef = *schema->objects()->Get(type_index);
78         auto s = objectdef.name()->str();
79         if (objectdef.is_struct()) {
80           s += "(struct)";  // TODO: implement this as well.
81         } else {
82           auto table_field = reinterpret_cast<const Table *>(
83                                ReadScalar<uoffset_t>(data) + data);
84           s += " { ";
85           auto fielddefs = objectdef.fields();
86           for (auto it = fielddefs->begin(); it != fielddefs->end(); ++it) {
87             auto &fielddef = **it;
88             if (!table_field->CheckField(fielddef.offset())) continue;
89             auto val = GetAnyFieldS(*table_field, fielddef, schema);
90             if (fielddef.type()->base_type() == reflection::String)
91               val = "\"" + val + "\"";  // Doesn't deal with escape codes etc.
92             s += fielddef.name()->str();
93             s += ": ";
94             s += val;
95             s += ", ";
96           }
97           s += "}";
98         }
99         return s;
100       } else {
101         return "(table)";
102       }
103     case reflection::Vector:
104       return "[(elements)]";  // TODO: implement this as well.
105     case reflection::Union:
106       return "(union)";  // TODO: implement this as well.
107     default: return NumToString(GetAnyValueI(type, data));
108   }
109 }
110 
SetAnyValueI(reflection::BaseType type,uint8_t * data,int64_t val)111 void SetAnyValueI(reflection::BaseType type, uint8_t *data, int64_t val) {
112 # define FLATBUFFERS_SET(T) WriteScalar(data, static_cast<T>(val))
113   switch (type) {
114     case reflection::UType:
115     case reflection::Bool:
116     case reflection::UByte:  FLATBUFFERS_SET(uint8_t ); break;
117     case reflection::Byte:   FLATBUFFERS_SET(int8_t  ); break;
118     case reflection::Short:  FLATBUFFERS_SET(int16_t ); break;
119     case reflection::UShort: FLATBUFFERS_SET(uint16_t); break;
120     case reflection::Int:    FLATBUFFERS_SET(int32_t ); break;
121     case reflection::UInt:   FLATBUFFERS_SET(uint32_t); break;
122     case reflection::Long:   FLATBUFFERS_SET(int64_t ); break;
123     case reflection::ULong:  FLATBUFFERS_SET(uint64_t); break;
124     case reflection::Float:  FLATBUFFERS_SET(float   ); break;
125     case reflection::Double: FLATBUFFERS_SET(double  ); break;
126     // TODO: support strings
127     default: break;
128   }
129 # undef FLATBUFFERS_SET
130 }
131 
SetAnyValueF(reflection::BaseType type,uint8_t * data,double val)132 void SetAnyValueF(reflection::BaseType type, uint8_t *data, double val) {
133   switch (type) {
134     case reflection::Float:  WriteScalar(data, static_cast<float>(val)); break;
135     case reflection::Double: WriteScalar(data, val); break;
136     // TODO: support strings.
137     default: SetAnyValueI(type, data, static_cast<int64_t>(val)); break;
138   }
139 }
140 
SetAnyValueS(reflection::BaseType type,uint8_t * data,const char * val)141 void SetAnyValueS(reflection::BaseType type, uint8_t *data, const char *val) {
142   switch (type) {
143     case reflection::Float:
144     case reflection::Double:
145       SetAnyValueF(type, data, strtod(val, nullptr));
146       break;
147     // TODO: support strings.
148     default: SetAnyValueI(type, data, StringToInt(val)); break;
149   }
150 }
151 
152 // Resize a FlatBuffer in-place by iterating through all offsets in the buffer
153 // and adjusting them by "delta" if they straddle the start offset.
154 // Once that is done, bytes can now be inserted/deleted safely.
155 // "delta" may be negative (shrinking).
156 // Unless "delta" is a multiple of the largest alignment, you'll create a small
157 // amount of garbage space in the buffer (usually 0..7 bytes).
158 // If your FlatBuffer's root table is not the schema's root table, you should
159 // pass in your root_table type as well.
160 class ResizeContext {
161  public:
ResizeContext(const reflection::Schema & schema,uoffset_t start,int delta,std::vector<uint8_t> * flatbuf,const reflection::Object * root_table=nullptr)162   ResizeContext(const reflection::Schema &schema, uoffset_t start, int delta,
163                 std::vector<uint8_t> *flatbuf,
164                 const reflection::Object *root_table = nullptr)
165      : schema_(schema), startptr_(flatbuf->data() + start),
166        delta_(delta), buf_(*flatbuf),
167        dag_check_(flatbuf->size() / sizeof(uoffset_t), false) {
168     auto mask = static_cast<int>(sizeof(largest_scalar_t) - 1);
169     delta_ = (delta_ + mask) & ~mask;
170     if (!delta_) return;  // We can't shrink by less than largest_scalar_t.
171     // Now change all the offsets by delta_.
172     auto root = GetAnyRoot(buf_.data());
173     Straddle<uoffset_t, 1>(buf_.data(), root, buf_.data());
174     ResizeTable(root_table ? *root_table : *schema.root_table(), root);
175     // We can now add or remove bytes at start.
176     if (delta_ > 0) buf_.insert(buf_.begin() + start, delta_, 0);
177     else buf_.erase(buf_.begin() + start, buf_.begin() + start - delta_);
178   }
179 
180   // Check if the range between first (lower address) and second straddles
181   // the insertion point. If it does, change the offset at offsetloc (of
182   // type T, with direction D).
Straddle(const void * first,const void * second,void * offsetloc)183   template<typename T, int D> void Straddle(const void *first,
184                                             const void *second,
185                                             void *offsetloc) {
186     if (first <= startptr_ && second >= startptr_) {
187       WriteScalar<T>(offsetloc, ReadScalar<T>(offsetloc) + delta_ * D);
188       DagCheck(offsetloc) = true;
189     }
190   }
191 
192   // This returns a boolean that records if the corresponding offset location
193   // has been modified already. If so, we can't even read the corresponding
194   // offset, since it is pointing to a location that is illegal until the
195   // resize actually happens.
196   // This must be checked for every offset, since we can't know which offsets
197   // will straddle and which won't.
DagCheck(const void * offsetloc)198   uint8_t &DagCheck(const void *offsetloc) {
199     auto dag_idx = reinterpret_cast<const uoffset_t *>(offsetloc) -
200                    reinterpret_cast<const uoffset_t *>(buf_.data());
201     return dag_check_[dag_idx];
202   }
203 
ResizeTable(const reflection::Object & objectdef,Table * table)204   void ResizeTable(const reflection::Object &objectdef, Table *table) {
205     if (DagCheck(table))
206       return;  // Table already visited.
207     auto vtable = table->GetVTable();
208     // Early out: since all fields inside the table must point forwards in
209     // memory, if the insertion point is before the table we can stop here.
210     auto tableloc = reinterpret_cast<uint8_t *>(table);
211     if (startptr_ <= tableloc) {
212       // Check if insertion point is between the table and a vtable that
213       // precedes it. This can't happen in current construction code, but check
214       // just in case we ever change the way flatbuffers are built.
215       Straddle<soffset_t, -1>(vtable, table, table);
216     } else {
217       // Check each field.
218       auto fielddefs = objectdef.fields();
219       for (auto it = fielddefs->begin(); it != fielddefs->end(); ++it) {
220         auto &fielddef = **it;
221         auto base_type = fielddef.type()->base_type();
222         // Ignore scalars.
223         if (base_type <= reflection::Double) continue;
224         // Ignore fields that are not stored.
225         auto offset = table->GetOptionalFieldOffset(fielddef.offset());
226         if (!offset) continue;
227         // Ignore structs.
228         auto subobjectdef = base_type == reflection::Obj ?
229           schema_.objects()->Get(fielddef.type()->index()) : nullptr;
230         if (subobjectdef && subobjectdef->is_struct()) continue;
231         // Get this fields' offset, and read it if safe.
232         auto offsetloc = tableloc + offset;
233         if (DagCheck(offsetloc))
234           continue;  // This offset already visited.
235         auto ref = offsetloc + ReadScalar<uoffset_t>(offsetloc);
236         Straddle<uoffset_t, 1>(offsetloc, ref, offsetloc);
237         // Recurse.
238         switch (base_type) {
239           case reflection::Obj: {
240             ResizeTable(*subobjectdef, reinterpret_cast<Table *>(ref));
241             break;
242           }
243           case reflection::Vector: {
244             auto elem_type = fielddef.type()->element();
245             if (elem_type != reflection::Obj && elem_type != reflection::String)
246               break;
247             auto vec = reinterpret_cast<Vector<uoffset_t> *>(ref);
248             auto elemobjectdef = elem_type == reflection::Obj
249               ? schema_.objects()->Get(fielddef.type()->index())
250               : nullptr;
251             if (elemobjectdef && elemobjectdef->is_struct()) break;
252             for (uoffset_t i = 0; i < vec->size(); i++) {
253               auto loc = vec->Data() + i * sizeof(uoffset_t);
254               if (DagCheck(loc))
255                 continue;  // This offset already visited.
256               auto dest = loc + vec->Get(i);
257               Straddle<uoffset_t, 1>(loc, dest ,loc);
258               if (elemobjectdef)
259                 ResizeTable(*elemobjectdef, reinterpret_cast<Table *>(dest));
260             }
261             break;
262           }
263           case reflection::Union: {
264             ResizeTable(GetUnionType(schema_, objectdef, fielddef, *table),
265                         reinterpret_cast<Table *>(ref));
266             break;
267           }
268           case reflection::String:
269             break;
270           default:
271             assert(false);
272         }
273       }
274       // Check if the vtable offset points beyond the insertion point.
275       // Must do this last, since GetOptionalFieldOffset above still reads
276       // this value.
277       Straddle<soffset_t, -1>(table, vtable, table);
278     }
279   }
280 
281   void operator=(const ResizeContext &rc);
282 
283  private:
284   const reflection::Schema &schema_;
285   uint8_t *startptr_;
286   int delta_;
287   std::vector<uint8_t> &buf_;
288   std::vector<uint8_t> dag_check_;
289 };
290 
SetString(const reflection::Schema & schema,const std::string & val,const String * str,std::vector<uint8_t> * flatbuf,const reflection::Object * root_table)291 void SetString(const reflection::Schema &schema, const std::string &val,
292                       const String *str, std::vector<uint8_t> *flatbuf,
293                       const reflection::Object *root_table) {
294   auto delta = static_cast<int>(val.size()) - static_cast<int>(str->Length());
295   auto str_start = static_cast<uoffset_t>(
296                      reinterpret_cast<const uint8_t *>(str) - flatbuf->data());
297   auto start = str_start + static_cast<uoffset_t>(sizeof(uoffset_t));
298   if (delta) {
299     // Clear the old string, since we don't want parts of it remaining.
300     memset(flatbuf->data() + start, 0, str->Length());
301     // Different size, we must expand (or contract).
302     ResizeContext(schema, start, delta, flatbuf, root_table);
303     // Set the new length.
304     WriteScalar(flatbuf->data() + str_start,
305                 static_cast<uoffset_t>(val.size()));
306   }
307   // Copy new data. Safe because we created the right amount of space.
308   memcpy(flatbuf->data() + start, val.c_str(), val.size() + 1);
309 }
310 
ResizeAnyVector(const reflection::Schema & schema,uoffset_t newsize,const VectorOfAny * vec,uoffset_t num_elems,uoffset_t elem_size,std::vector<uint8_t> * flatbuf,const reflection::Object * root_table)311 uint8_t *ResizeAnyVector(const reflection::Schema &schema, uoffset_t newsize,
312                          const VectorOfAny *vec, uoffset_t num_elems,
313                          uoffset_t elem_size, std::vector<uint8_t> *flatbuf,
314                          const reflection::Object *root_table) {
315   auto delta_elem = static_cast<int>(newsize) - static_cast<int>(num_elems);
316   auto delta_bytes = delta_elem * static_cast<int>(elem_size);
317   auto vec_start = reinterpret_cast<const uint8_t *>(vec) - flatbuf->data();
318   auto start = static_cast<uoffset_t>(vec_start + sizeof(uoffset_t) +
319                                       elem_size * num_elems);
320   if (delta_bytes) {
321     if (delta_elem < 0) {
322       // Clear elements we're throwing away, since some might remain in the
323       // buffer.
324       auto size_clear = -delta_elem * elem_size;
325       memset(flatbuf->data() + start - size_clear, 0, size_clear);
326     }
327     ResizeContext(schema, start, delta_bytes, flatbuf, root_table);
328     WriteScalar(flatbuf->data() + vec_start, newsize);  // Length field.
329     // Set new elements to 0.. this can be overwritten by the caller.
330     if (delta_elem > 0) {
331       memset(flatbuf->data() + start, 0, delta_elem * elem_size);
332     }
333   }
334   return flatbuf->data() + start;
335 }
336 
AddFlatBuffer(std::vector<uint8_t> & flatbuf,const uint8_t * newbuf,size_t newlen)337 const uint8_t *AddFlatBuffer(std::vector<uint8_t> &flatbuf,
338                              const uint8_t *newbuf, size_t newlen) {
339   // Align to sizeof(uoffset_t) past sizeof(largest_scalar_t) since we're
340   // going to chop off the root offset.
341   while ((flatbuf.size() & (sizeof(uoffset_t) - 1)) ||
342          !(flatbuf.size() & (sizeof(largest_scalar_t) - 1))) {
343     flatbuf.push_back(0);
344   }
345   auto insertion_point = static_cast<uoffset_t>(flatbuf.size());
346   // Insert the entire FlatBuffer minus the root pointer.
347   flatbuf.insert(flatbuf.end(), newbuf + sizeof(uoffset_t), newbuf + newlen);
348   auto root_offset = ReadScalar<uoffset_t>(newbuf) - sizeof(uoffset_t);
349   return flatbuf.data() + insertion_point + root_offset;
350 }
351 
CopyInline(FlatBufferBuilder & fbb,const reflection::Field & fielddef,const Table & table,size_t align,size_t size)352 void CopyInline(FlatBufferBuilder &fbb, const reflection::Field &fielddef,
353                 const Table &table, size_t align, size_t size) {
354   fbb.Align(align);
355   fbb.PushBytes(table.GetStruct<const uint8_t *>(fielddef.offset()), size);
356   fbb.TrackField(fielddef.offset(), fbb.GetSize());
357 }
358 
CopyTable(FlatBufferBuilder & fbb,const reflection::Schema & schema,const reflection::Object & objectdef,const Table & table,bool use_string_pooling)359 Offset<const Table *> CopyTable(FlatBufferBuilder &fbb,
360                                 const reflection::Schema &schema,
361                                 const reflection::Object &objectdef,
362                                 const Table &table,
363                                 bool use_string_pooling) {
364   // Before we can construct the table, we have to first generate any
365   // subobjects, and collect their offsets.
366   std::vector<uoffset_t> offsets;
367   auto fielddefs = objectdef.fields();
368   for (auto it = fielddefs->begin(); it != fielddefs->end(); ++it) {
369     auto &fielddef = **it;
370     // Skip if field is not present in the source.
371     if (!table.CheckField(fielddef.offset())) continue;
372     uoffset_t offset = 0;
373     switch (fielddef.type()->base_type()) {
374       case reflection::String: {
375         offset = use_string_pooling
376                  ? fbb.CreateSharedString(GetFieldS(table, fielddef)).o
377                  : fbb.CreateString(GetFieldS(table, fielddef)).o;
378         break;
379       }
380       case reflection::Obj: {
381         auto &subobjectdef = *schema.objects()->Get(fielddef.type()->index());
382         if (!subobjectdef.is_struct()) {
383           offset = CopyTable(fbb, schema, subobjectdef,
384                              *GetFieldT(table, fielddef)).o;
385         }
386         break;
387       }
388       case reflection::Union: {
389         auto &subobjectdef = GetUnionType(schema, objectdef, fielddef, table);
390         offset = CopyTable(fbb, schema, subobjectdef,
391                            *GetFieldT(table, fielddef)).o;
392         break;
393       }
394       case reflection::Vector: {
395         auto vec = table.GetPointer<const Vector<Offset<Table>> *>(
396                                                              fielddef.offset());
397         auto element_base_type = fielddef.type()->element();
398         auto elemobjectdef = element_base_type == reflection::Obj
399                              ? schema.objects()->Get(fielddef.type()->index())
400                              : nullptr;
401         switch (element_base_type) {
402           case reflection::String: {
403             std::vector<Offset<const String *>> elements(vec->size());
404             auto vec_s = reinterpret_cast<const Vector<Offset<String>> *>(vec);
405             for (uoffset_t i = 0; i < vec_s->size(); i++) {
406               elements[i] = use_string_pooling
407                             ? fbb.CreateSharedString(vec_s->Get(i)).o
408                             : fbb.CreateString(vec_s->Get(i)).o;
409             }
410             offset = fbb.CreateVector(elements).o;
411             break;
412           }
413           case reflection::Obj: {
414             if (!elemobjectdef->is_struct()) {
415               std::vector<Offset<const Table *>> elements(vec->size());
416               for (uoffset_t i = 0; i < vec->size(); i++) {
417                 elements[i] =
418                   CopyTable(fbb, schema, *elemobjectdef, *vec->Get(i));
419               }
420               offset = fbb.CreateVector(elements).o;
421               break;
422             }
423             // FALL-THRU:
424           }
425           default: {  // Scalars and structs.
426             auto element_size = GetTypeSize(element_base_type);
427             if (elemobjectdef && elemobjectdef->is_struct())
428               element_size = elemobjectdef->bytesize();
429             fbb.StartVector(element_size, vec->size());
430             fbb.PushBytes(vec->Data(), element_size * vec->size());
431             offset = fbb.EndVector(vec->size());
432             break;
433           }
434         }
435         break;
436       }
437       default:  // Scalars.
438         break;
439     }
440     if (offset) {
441       offsets.push_back(offset);
442     }
443   }
444   // Now we can build the actual table from either offsets or scalar data.
445   auto start = objectdef.is_struct()
446                  ? fbb.StartStruct(objectdef.minalign())
447                  : fbb.StartTable();
448   size_t offset_idx = 0;
449   for (auto it = fielddefs->begin(); it != fielddefs->end(); ++it) {
450     auto &fielddef = **it;
451     if (!table.CheckField(fielddef.offset())) continue;
452     auto base_type = fielddef.type()->base_type();
453     switch (base_type) {
454       case reflection::Obj: {
455         auto &subobjectdef = *schema.objects()->Get(fielddef.type()->index());
456         if (subobjectdef.is_struct()) {
457           CopyInline(fbb, fielddef, table, subobjectdef.minalign(),
458                      subobjectdef.bytesize());
459           break;
460         }
461         // else: FALL-THRU:
462       }
463       case reflection::Union:
464       case reflection::String:
465       case reflection::Vector:
466         fbb.AddOffset(fielddef.offset(), Offset<void>(offsets[offset_idx++]));
467         break;
468       default: { // Scalars.
469         auto size = GetTypeSize(base_type);
470         CopyInline(fbb, fielddef, table, size, size);
471         break;
472       }
473     }
474   }
475   assert(offset_idx == offsets.size());
476   if (objectdef.is_struct()) {
477     fbb.ClearOffsets();
478     return fbb.EndStruct();
479   } else {
480     return fbb.EndTable(start, static_cast<voffset_t>(fielddefs->size()));
481   }
482 }
483 
VerifyStruct(flatbuffers::Verifier & v,const flatbuffers::Table & parent_table,voffset_t field_offset,const reflection::Object & obj,bool required)484 bool VerifyStruct(flatbuffers::Verifier &v,
485                   const flatbuffers::Table &parent_table,
486                   voffset_t field_offset,
487                   const reflection::Object &obj,
488                   bool required) {
489   auto offset = parent_table.GetOptionalFieldOffset(field_offset);
490   if (required && !offset) {
491     return false;
492   }
493 
494   return !offset || v.Verify(reinterpret_cast<const uint8_t*>(&parent_table)
495                              + offset, obj.bytesize());
496 }
497 
VerifyVectorOfStructs(flatbuffers::Verifier & v,const flatbuffers::Table & parent_table,voffset_t field_offset,const reflection::Object & obj,bool required)498 bool VerifyVectorOfStructs(flatbuffers::Verifier &v,
499                            const flatbuffers::Table &parent_table,
500                            voffset_t field_offset,
501                            const reflection::Object &obj,
502                            bool required) {
503   auto p = parent_table.GetPointer<const uint8_t*>(field_offset);
504   const uint8_t* end;
505   if (required && !p) {
506     return false;
507   }
508 
509   return !p || v.VerifyVector(p, obj.bytesize(), &end);
510 }
511 
512 // forward declare to resolve cyclic deps between VerifyObject and VerifyVector
513 bool VerifyObject(flatbuffers::Verifier &v,
514                   const reflection::Schema &schema,
515                   const reflection::Object &obj,
516                   const flatbuffers::Table *table,
517                   bool isRequired);
518 
VerifyVector(flatbuffers::Verifier & v,const reflection::Schema & schema,const flatbuffers::Table & table,const reflection::Field & vec_field)519 bool VerifyVector(flatbuffers::Verifier &v,
520                   const reflection::Schema &schema,
521                   const flatbuffers::Table &table,
522                   const reflection::Field &vec_field) {
523   assert(vec_field.type()->base_type() == reflection::Vector);
524   if (!table.VerifyField<uoffset_t>(v, vec_field.offset()))
525     return false;
526 
527   switch (vec_field.type()->element()) {
528     case reflection::None:
529       assert(false);
530       break;
531     case reflection::UType:
532       return v.Verify(flatbuffers::GetFieldV<uint8_t>(table, vec_field));
533     case reflection::Bool:
534     case reflection::Byte:
535     case reflection::UByte:
536       return v.Verify(flatbuffers::GetFieldV<int8_t>(table, vec_field));
537     case reflection::Short:
538     case reflection::UShort:
539       return v.Verify(flatbuffers::GetFieldV<int16_t>(table, vec_field));
540     case reflection::Int:
541     case reflection::UInt:
542       return v.Verify(flatbuffers::GetFieldV<int32_t>(table, vec_field));
543     case reflection::Long:
544     case reflection::ULong:
545       return v.Verify(flatbuffers::GetFieldV<int64_t>(table, vec_field));
546     case reflection::Float:
547       return v.Verify(flatbuffers::GetFieldV<float>(table, vec_field));
548     case reflection::Double:
549       return v.Verify(flatbuffers::GetFieldV<double>(table, vec_field));
550     case reflection::String: {
551       auto vecString =
552         flatbuffers::GetFieldV<flatbuffers::
553         Offset<flatbuffers::String>>(table, vec_field);
554       if (v.Verify(vecString) && v.VerifyVectorOfStrings(vecString)) {
555         return true;
556       } else {
557         return false;
558       }
559     }
560     case reflection::Vector:
561       assert(false);
562       break;
563     case reflection::Obj: {
564       auto obj = schema.objects()->Get(vec_field.type()->index());
565       if (obj->is_struct()) {
566         if (!VerifyVectorOfStructs(v, table, vec_field.offset(), *obj,
567                                    vec_field.required())) {
568           return false;
569         }
570       } else {
571         auto vec =
572           flatbuffers::GetFieldV<flatbuffers::
573           Offset<flatbuffers::Table>>(table, vec_field);
574         if (!v.Verify(vec))
575           return false;
576         if (vec) {
577           for (uoffset_t j = 0; j < vec->size(); j++) {
578             if (!VerifyObject(v, schema, *obj, vec->Get(j), true)) {
579               return false;
580             }
581           }
582         }
583       }
584       return true;
585     }
586     case reflection::Union:
587       assert(false);
588       break;
589     default:
590       assert(false);
591       break;
592   }
593 
594   return false;
595 }
596 
VerifyObject(flatbuffers::Verifier & v,const reflection::Schema & schema,const reflection::Object & obj,const flatbuffers::Table * table,bool required)597 bool VerifyObject(flatbuffers::Verifier &v,
598                   const reflection::Schema &schema,
599                   const reflection::Object &obj,
600                   const flatbuffers::Table *table,
601                   bool required) {
602   if (!table) {
603     if (!required)
604       return true;
605     else
606       return false;
607   }
608 
609   if (!table->VerifyTableStart(v))
610     return false;
611 
612   for (uoffset_t i = 0; i < obj.fields()->size(); i++) {
613     auto field_def = obj.fields()->Get(i);
614     switch (field_def->type()->base_type()) {
615       case reflection::None:
616         assert(false);
617         break;
618       case reflection::UType:
619         if (!table->VerifyField<uint8_t>(v, field_def->offset()))
620           return false;
621         break;
622       case reflection::Bool:
623       case reflection::Byte:
624       case reflection::UByte:
625         if (!table->VerifyField<int8_t>(v, field_def->offset()))
626           return false;
627         break;
628       case reflection::Short:
629       case reflection::UShort:
630         if (!table->VerifyField<int16_t>(v, field_def->offset()))
631           return false;
632         break;
633       case reflection::Int:
634       case reflection::UInt:
635         if (!table->VerifyField<int32_t>(v, field_def->offset()))
636           return false;
637         break;
638       case reflection::Long:
639       case reflection::ULong:
640         if (!table->VerifyField<int64_t>(v, field_def->offset()))
641           return false;
642         break;
643       case reflection::Float:
644         if (!table->VerifyField<float>(v, field_def->offset()))
645           return false;
646         break;
647       case reflection::Double:
648         if (!table->VerifyField<double>(v, field_def->offset()))
649           return false;
650         break;
651       case reflection::String:
652         if (!table->VerifyField<uoffset_t>(v, field_def->offset()) ||
653             !v.Verify(flatbuffers::GetFieldS(*table, *field_def))) {
654           return false;
655         }
656         break;
657       case reflection::Vector:
658         if (!VerifyVector(v, schema, *table, *field_def))
659           return false;
660         break;
661       case reflection::Obj: {
662         auto child_obj = schema.objects()->Get(field_def->type()->index());
663         if (child_obj->is_struct()) {
664           if (!VerifyStruct(v, *table, field_def->offset(), *child_obj,
665                             field_def->required())) {
666             return false;
667           }
668         } else {
669           if (!VerifyObject(v, schema, *child_obj,
670                             flatbuffers::GetFieldT(*table, *field_def),
671                             field_def->required())) {
672             return false;
673           }
674         }
675         break;
676       }
677       case reflection::Union: {
678         //  get union type from the prev field
679         voffset_t utype_offset = field_def->offset() - sizeof(voffset_t);
680         auto utype = table->GetField<uint8_t>(utype_offset, 0);
681         if (utype != 0) {
682           // Means we have this union field present
683           auto fb_enum = schema.enums()->Get(field_def->type()->index());
684           auto child_obj = fb_enum->values()->Get(utype)->object();
685           if (!VerifyObject(v, schema, *child_obj,
686                             flatbuffers::GetFieldT(*table, *field_def),
687                             field_def->required())) {
688             return false;
689           }
690         }
691         break;
692       }
693       default:
694         assert(false);
695         break;
696     }
697   }
698 
699   return true;
700 }
701 
Verify(const reflection::Schema & schema,const reflection::Object & root,const uint8_t * buf,size_t length)702 bool Verify(const reflection::Schema &schema,
703             const reflection::Object &root,
704             const uint8_t *buf,
705             size_t length) {
706   Verifier v(buf, length);
707   return VerifyObject(v, schema, root, flatbuffers::GetAnyRoot(buf), true);
708 }
709 
710 }  // namespace flatbuffers
711