Merge branch 'master' of https://github.com/google/flatbuffers

CMakeLists.txt

@@ -203,6 +203,9 @@ if(FLATBUFFERS_BUILD_TESTS)
   compile_flatbuffers_schema_to_cpp(tests/monster_test.fbs)
   include_directories(${CMAKE_CURRENT_BINARY_DIR}/tests)
   add_executable(flattests ${FlatBuffers_Tests_SRCS})
+  set_property(TARGET flattests
+    PROPERTY COMPILE_DEFINITIONS FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
+    FLATBUFFERS_DEBUG_VERIFICATION_FAILURE=1)
 
   compile_flatbuffers_schema_to_cpp(samples/monster.fbs)
   include_directories(${CMAKE_CURRENT_BINARY_DIR}/samples)

include/flatbuffers/flatbuffers.h

@@ -252,9 +252,9 @@ template<typename T> struct IndirectHelper<const T *> {
 // calling Get() for every element.
 template<typename T, typename IT>
 struct VectorIterator
-    : public std::iterator<std::input_iterator_tag, IT, uoffset_t> {
+    : public std::iterator<std::random_access_iterator_tag, IT, uoffset_t> {
 
-  typedef std::iterator<std::input_iterator_tag, IT, uoffset_t> super_type;
+  typedef std::iterator<std::random_access_iterator_tag, IT, uoffset_t> super_type;
 
 public:
   VectorIterator(const uint8_t *data, uoffset_t i) :
@@ -274,15 +274,15 @@ public:
     return *this;
   }
 
-  bool operator==(const VectorIterator& other) const {
+  bool operator==(const VectorIterator &other) const {
     return data_ == other.data_;
   }
 
-  bool operator!=(const VectorIterator& other) const {
+  bool operator!=(const VectorIterator &other) const {
     return data_ != other.data_;
   }
 
-  ptrdiff_t operator-(const VectorIterator& other) const {
+  ptrdiff_t operator-(const VectorIterator &other) const {
     return (data_ - other.data_) / IndirectHelper<T>::element_stride;
   }
 
@@ -300,11 +300,40 @@ public:
   }
 
   VectorIterator operator++(int) {
-    VectorIterator temp(data_,0);
+    VectorIterator temp(data_, 0);
     data_ += IndirectHelper<T>::element_stride;
     return temp;
   }
 
+  VectorIterator operator+(const uoffset_t &offset) {
+    return VectorIterator(data_ + offset * IndirectHelper<T>::element_stride, 0);
+  }
+
+  VectorIterator& operator+=(const uoffset_t &offset) {
+    data_ += offset * IndirectHelper<T>::element_stride;
+    return *this;
+  }
+
+  VectorIterator &operator--() {
+    data_ -= IndirectHelper<T>::element_stride;
+    return *this;
+  }
+
+  VectorIterator operator--(int) {
+    VectorIterator temp(data_, 0);
+    data_ -= IndirectHelper<T>::element_stride;
+    return temp;
+  }
+
+  VectorIterator operator-(const uoffset_t &offset) {
+    return VectorIterator(data_ - offset * IndirectHelper<T>::element_stride, 0);
+  }
+
+  VectorIterator& operator-=(const uoffset_t &offset) {
+    data_ -= offset * IndirectHelper<T>::element_stride;
+    return *this;
+  }
+
 private:
   const uint8_t *data_;
 };
@@ -1453,9 +1482,9 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
   size_t max_depth_;
   size_t num_tables_;
   size_t max_tables_;
-  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
+#ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
   mutable const uint8_t *upper_bound_;
-  #endif
+#endif
 };
 
 // Convenient way to bundle a buffer and its length, to pass it around

include/flatbuffers/reflection.h

@@ -428,6 +428,15 @@ Offset<const Table *> CopyTable(FlatBufferBuilder &fbb,
                                 const Table &table,
                                 bool use_string_pooling = false);
 
+// Verifies the provided flatbuffer using reflection.
+// root should point to the root type for this flatbuffer.
+// buf should point to the start of flatbuffer data.
+// length specifies the size of the flatbuffer data.
+bool Verify(const reflection::Schema &schema,
+            const reflection::Object &root,
+            const uint8_t *buf,
+            size_t length);
+
 }  // namespace flatbuffers
 
 #endif  // FLATBUFFERS_REFLECTION_H_

src/reflection.cpp

@@ -481,4 +481,230 @@ Offset<const Table *> CopyTable(FlatBufferBuilder &fbb,
   }
 }
 
+bool VerifyStruct(flatbuffers::Verifier &v,
+                  const flatbuffers::Table &parent_table,
+                  voffset_t field_offset,
+                  const reflection::Object &obj,
+                  bool required) {  
+  auto offset = parent_table.GetOptionalFieldOffset(field_offset);
+  if (required && !offset) {
+    return false;
+  }
+
+  return !offset || v.Verify(reinterpret_cast<const uint8_t*>(&parent_table)
+                             + offset, obj.bytesize());  
+}
+
+bool VerifyVectorOfStructs(flatbuffers::Verifier &v,
+                           const flatbuffers::Table &parent_table,
+                           voffset_t field_offset,
+                           const reflection::Object &obj,
+                           bool required) {
+  auto p = parent_table.GetPointer<const uint8_t*>(field_offset);
+  const uint8_t* end;
+  if (required && !p) {
+    return false;
+  }
+
+  return !p || v.VerifyVector(p, obj.bytesize(), &end);
+}
+
+// forward declare to resolve cyclic deps between VerifyObject and VerifyVector
+bool VerifyObject(flatbuffers::Verifier &v,
+                  const reflection::Schema &schema,
+                  const reflection::Object &obj,
+                  const flatbuffers::Table *table,
+                  bool isRequired);
+
+bool VerifyVector(flatbuffers::Verifier &v,
+                  const reflection::Schema &schema,
+                  const flatbuffers::Table &table,
+                  const reflection::Field &vec_field) {
+  assert(vec_field.type()->base_type() == reflection::BaseType::Vector);
+  if (!table.VerifyField<uoffset_t>(v, vec_field.offset()))
+    return false;
+
+  switch (vec_field.type()->element()) {
+    case reflection::BaseType::None:
+      assert(false);
+      break;
+    case reflection::BaseType::UType:
+      return v.Verify(flatbuffers::GetFieldV<uint8_t>(table, vec_field));
+    case reflection::BaseType::Bool:
+    case reflection::BaseType::Byte:
+    case reflection::BaseType::UByte:
+      return v.Verify(flatbuffers::GetFieldV<int8_t>(table, vec_field));
+    case reflection::BaseType::Short:
+    case reflection::BaseType::UShort:
+      return v.Verify(flatbuffers::GetFieldV<int16_t>(table, vec_field));
+    case reflection::BaseType::Int:
+    case reflection::BaseType::UInt:
+      return v.Verify(flatbuffers::GetFieldV<int32_t>(table, vec_field));
+    case reflection::BaseType::Long:
+    case reflection::BaseType::ULong:
+      return v.Verify(flatbuffers::GetFieldV<int64_t>(table, vec_field));
+    case reflection::BaseType::Float:
+      return v.Verify(flatbuffers::GetFieldV<float>(table, vec_field));
+    case reflection::BaseType::Double:
+      return v.Verify(flatbuffers::GetFieldV<double>(table, vec_field));
+    case reflection::BaseType::String: {
+      auto vecString =
+        flatbuffers::GetFieldV<flatbuffers::
+        Offset<flatbuffers::String>>(table, vec_field);
+      if (v.Verify(vecString) && v.VerifyVectorOfStrings(vecString)) {
+        return true;
+      } else {
+        return false;
+      }
+    }
+    case reflection::BaseType::Vector:
+      assert(false);
+      break;
+    case reflection::BaseType::Obj: {
+      auto obj = schema.objects()->Get(vec_field.type()->index());
+      if (obj->is_struct()) {
+        if (!VerifyVectorOfStructs(v, table, vec_field.offset(), *obj,
+                                   vec_field.required())) {
+          return false;
+        }
+      } else {
+        auto vec =
+          flatbuffers::GetFieldV<flatbuffers::
+          Offset<flatbuffers::Table>>(table, vec_field);
+        if (!v.Verify(vec))
+          return false;
+        if (vec) {
+          for (uoffset_t j = 0; j < vec->size(); j++) {
+            if (!VerifyObject(v, schema, *obj, vec->Get(j), true)) {
+              return false;
+            }
+          }
+        }
+      }
+      return true;
+    }
+    case reflection::BaseType::Union:
+      assert(false);
+      break;
+    default:
+      assert(false);
+      break;
+  }
+
+  return false;
+}
+
+bool VerifyObject(flatbuffers::Verifier &v,
+                  const reflection::Schema &schema,
+                  const reflection::Object &obj,
+                  const flatbuffers::Table *table,
+                  bool required) {
+  if (!table) {
+    if (!required)
+      return true;
+    else
+      return false;
+  }
+
+  if (!table->VerifyTableStart(v))
+    return false;
+
+  for (size_t i = 0; i < obj.fields()->size(); i++) {
+    auto field_def = obj.fields()->Get(i);
+    switch (field_def->type()->base_type()) {
+      case reflection::BaseType::None:
+        assert(false);
+        break;
+      case reflection::BaseType::UType:
+        if (!table->VerifyField<uint8_t>(v, field_def->offset()))
+          return false;
+        break;
+      case reflection::BaseType::Bool:
+      case reflection::BaseType::Byte:
+      case reflection::BaseType::UByte:
+        if (!table->VerifyField<int8_t>(v, field_def->offset()))
+          return false;
+        break;
+      case reflection::BaseType::Short:
+      case reflection::BaseType::UShort:
+        if (!table->VerifyField<int16_t>(v, field_def->offset()))
+          return false;
+        break;
+      case reflection::BaseType::Int:
+      case reflection::BaseType::UInt:
+        if (!table->VerifyField<int32_t>(v, field_def->offset()))
+          return false;
+        break;
+      case reflection::BaseType::Long:
+      case reflection::BaseType::ULong:
+        if (!table->VerifyField<int64_t>(v, field_def->offset()))
+          return false;
+        break;
+      case reflection::BaseType::Float:
+        if (!table->VerifyField<float>(v, field_def->offset()))
+          return false;
+        break;
+      case reflection::BaseType::Double:
+        if (!table->VerifyField<double>(v, field_def->offset()))
+          return false;
+        break;
+      case reflection::BaseType::String:
+        if (!table->VerifyField<uoffset_t>(v, field_def->offset()) ||
+            !v.Verify(flatbuffers::GetFieldS(*table, *field_def))) {
+          return false;
+        }
+        break;
+      case reflection::BaseType::Vector:
+        if (!VerifyVector(v, schema, *table, *field_def))
+          return false;
+        break;
+      case reflection::BaseType::Obj: {
+        auto child_obj = schema.objects()->Get(field_def->type()->index());
+        if (child_obj->is_struct()) {
+          if (!VerifyStruct(v, *table, field_def->offset(), *child_obj,
+                            field_def->required())) {
+            return false;
+          }
+        } else {
+          if (!VerifyObject(v, schema, *child_obj,
+                            flatbuffers::GetFieldT(*table, *field_def),
+                            field_def->required())) {
+            return false;
+          }
+        }
+        break;
+      }
+      case reflection::BaseType::Union: {
+        //  get union type from the prev field 
+        voffset_t utype_offset = field_def->offset() - sizeof(voffset_t);
+        auto utype = table->GetField<uint8_t>(utype_offset, 0);
+        if (utype != 0) {
+          // Means we have this union field present
+          auto fb_enum = schema.enums()->Get(field_def->type()->index());
+          auto child_obj = fb_enum->values()->Get(utype)->object();
+          if (!VerifyObject(v, schema, *child_obj,
+                            flatbuffers::GetFieldT(*table, *field_def),
+                            field_def->required())) {
+            return false;
+          }
+        }
+        break;
+      }
+      default:
+        assert(false);
+        break;
+    }
+  }
+
+  return true;
+}
+
+bool Verify(const reflection::Schema &schema,
+            const reflection::Object &root,
+            const uint8_t *buf,
+            size_t length) {
+  Verifier v(buf, length);
+  return VerifyObject(v, schema, root, flatbuffers::GetAnyRoot(buf), true);
+}
+
 }  // namespace flatbuffers

tests/test.cpp

@@ -14,9 +14,6 @@
  * limitations under the License.
  */
 
-#define FLATBUFFERS_DEBUG_VERIFICATION_FAILURE 1
-#define FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
-
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
@@ -493,8 +490,15 @@ void ReflectionTest(uint8_t *flatbuf, size_t length) {
   TEST_NOTNULL(pos_table_ptr);
   TEST_EQ_STR(pos_table_ptr->name()->c_str(), "MyGame.Example.Vec3");
 
+  
+
   // Now use it to dynamically access a buffer.
   auto &root = *flatbuffers::GetAnyRoot(flatbuf);
+
+  // Verify the buffer first using reflection based verification
+  TEST_EQ(flatbuffers::Verify(schema, *schema.root_table(), flatbuf, length),
+          true);
+
   auto hp = flatbuffers::GetFieldI<uint16_t>(root, hp_field);
   TEST_EQ(hp, 80);
 
@@ -523,6 +527,10 @@ void ReflectionTest(uint8_t *flatbuf, size_t length) {
   hp_int64 = flatbuffers::GetAnyFieldI(root, hp_field);
   TEST_EQ(hp_int64, 300);
 
+  // Test buffer is valid after the modifications
+  TEST_EQ(flatbuffers::Verify(schema, *schema.root_table(), flatbuf, length),
+          true);
+
   // Reset it, for further tests.
   flatbuffers::SetField<uint16_t>(&root, hp_field, 80);
 
@@ -584,6 +592,11 @@ void ReflectionTest(uint8_t *flatbuf, size_t length) {
         reinterpret_cast<const uint8_t *>(resizingbuf.data()),
         resizingbuf.size());
   TEST_EQ(VerifyMonsterBuffer(resize_verifier), true);
+    
+  // Test buffer is valid using reflection as well
+  TEST_EQ(flatbuffers::Verify(schema, *schema.root_table(), resizingbuf.data(),
+                              resizingbuf.size()), true);
+  
   // As an additional test, also set it on the name field.
   // Note: unlike the name change above, this just overwrites the offset,
   // rather than changing the string in-place.
@@ -600,6 +613,10 @@ void ReflectionTest(uint8_t *flatbuf, size_t length) {
   fbb.Finish(root_offset, MonsterIdentifier());
   // Test that it was copied correctly:
   AccessFlatBufferTest(fbb.GetBufferPointer(), fbb.GetSize());
+
+  // Test buffer is valid using reflection as well
+  TEST_EQ(flatbuffers::Verify(schema, *schema.root_table(),
+                              fbb.GetBufferPointer(), fbb.GetSize()), true);
 }
 
 // Parse a .proto schema, output as .fbs