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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/symbols.h"
#include "vm/handles.h"
#include "vm/hash_table.h"
#include "vm/isolate.h"
#include "vm/object.h"
#include "vm/object_store.h"
#include "vm/raw_object.h"
#include "vm/reusable_handles.h"
#include "vm/snapshot_ids.h"
#include "vm/unicode.h"
#include "vm/visitor.h"
namespace dart {
RawString* Symbols::predefined_[Symbols::kNumberOfOneCharCodeSymbols];
String* Symbols::symbol_handles_[Symbols::kMaxPredefinedId];
static const char* names[] = {
// clang-format off
NULL,
#define DEFINE_SYMBOL_LITERAL(symbol, literal) literal,
PREDEFINED_SYMBOLS_LIST(DEFINE_SYMBOL_LITERAL)
#undef DEFINE_SYMBOL_LITERAL
"", // matches kTokenTableStart.
#define DEFINE_TOKEN_SYMBOL_INDEX(t, s, p, a) s,
DART_TOKEN_LIST(DEFINE_TOKEN_SYMBOL_INDEX)
DART_KEYWORD_LIST(DEFINE_TOKEN_SYMBOL_INDEX)
#undef DEFINE_TOKEN_SYMBOL_INDEX
// clang-format on
};
RawString* StringFrom(const uint8_t* data, intptr_t len, Heap::Space space) {
return String::FromLatin1(data, len, space);
}
RawString* StringFrom(const uint16_t* data, intptr_t len, Heap::Space space) {
return String::FromUTF16(data, len, space);
}
RawString* StringFrom(const int32_t* data, intptr_t len, Heap::Space space) {
return String::FromUTF32(data, len, space);
}
template <typename CharType>
class CharArray {
public:
CharArray(const CharType* data, intptr_t len) : data_(data), len_(len) {
hash_ = String::Hash(data, len);
}
RawString* ToSymbol() const {
String& result = String::Handle(StringFrom(data_, len_, Heap::kOld));
result.SetCanonical();
result.SetHash(hash_);
return result.raw();
}
bool Equals(const String& other) const {
ASSERT(other.HasHash());
if (other.Hash() != hash_) {
return false;
}
return other.Equals(data_, len_);
}
intptr_t Hash() const { return hash_; }
private:
const CharType* data_;
intptr_t len_;
intptr_t hash_;
};
typedef CharArray<uint8_t> Latin1Array;
typedef CharArray<uint16_t> UTF16Array;
typedef CharArray<int32_t> UTF32Array;
class StringSlice {
public:
StringSlice(const String& str, intptr_t begin_index, intptr_t length)
: str_(str), begin_index_(begin_index), len_(length) {
hash_ = is_all() ? str.Hash() : String::Hash(str, begin_index, length);
}
RawString* ToSymbol() const;
bool Equals(const String& other) const {
ASSERT(other.HasHash());
if (other.Hash() != hash_) {
return false;
}
return other.Equals(str_, begin_index_, len_);
}
intptr_t Hash() const { return hash_; }
private:
bool is_all() const { return begin_index_ == 0 && len_ == str_.Length(); }
const String& str_;
intptr_t begin_index_;
intptr_t len_;
intptr_t hash_;
};
RawString* StringSlice::ToSymbol() const {
if (is_all() && str_.IsOld()) {
str_.SetCanonical();
return str_.raw();
} else {
String& result =
String::Handle(String::SubString(str_, begin_index_, len_, Heap::kOld));
result.SetCanonical();
result.SetHash(hash_);
return result.raw();
}
}
class ConcatString {
public:
ConcatString(const String& str1, const String& str2)
: str1_(str1), str2_(str2), hash_(String::HashConcat(str1, str2)) {}
RawString* ToSymbol() const;
bool Equals(const String& other) const {
ASSERT(other.HasHash());
if (other.Hash() != hash_) {
return false;
}
return other.EqualsConcat(str1_, str2_);
}
intptr_t Hash() const { return hash_; }
private:
const String& str1_;
const String& str2_;
intptr_t hash_;
};
RawString* ConcatString::ToSymbol() const {
String& result = String::Handle(String::Concat(str1_, str2_, Heap::kOld));
result.SetCanonical();
result.SetHash(hash_);
return result.raw();
}
class SymbolTraits {
public:
static const char* Name() { return "SymbolTraits"; }
static bool ReportStats() { return false; }
static bool IsMatch(const Object& a, const Object& b) {
const String& a_str = String::Cast(a);
const String& b_str = String::Cast(b);
ASSERT(a_str.HasHash());
ASSERT(b_str.HasHash());
if (a_str.Hash() != b_str.Hash()) {
return false;
}
intptr_t a_len = a_str.Length();
if (a_len != b_str.Length()) {
return false;
}
// Use a comparison which does not consider the state of the canonical bit.
return a_str.Equals(b_str, 0, a_len);
}
template <typename CharType>
static bool IsMatch(const CharArray<CharType>& array, const Object& obj) {
return array.Equals(String::Cast(obj));
}
static bool IsMatch(const StringSlice& slice, const Object& obj) {
return slice.Equals(String::Cast(obj));
}
static bool IsMatch(const ConcatString& concat, const Object& obj) {
return concat.Equals(String::Cast(obj));
}
static uword Hash(const Object& key) { return String::Cast(key).Hash(); }
template <typename CharType>
static uword Hash(const CharArray<CharType>& array) {
return array.Hash();
}
static uword Hash(const StringSlice& slice) { return slice.Hash(); }
static uword Hash(const ConcatString& concat) { return concat.Hash(); }
template <typename CharType>
static RawObject* NewKey(const CharArray<CharType>& array) {
return array.ToSymbol();
}
static RawObject* NewKey(const StringSlice& slice) {
return slice.ToSymbol();
}
static RawObject* NewKey(const ConcatString& concat) {
return concat.ToSymbol();
}
};
typedef UnorderedHashSet<SymbolTraits> SymbolTable;
const char* Symbols::Name(SymbolId symbol) {
ASSERT((symbol > kIllegal) && (symbol < kNullCharId));
return names[symbol];
}
const String& Symbols::Token(Token::Kind token) {
const int tok_index = token;
ASSERT((0 <= tok_index) && (tok_index < Token::kNumTokens));
// First keyword symbol is in symbol_handles_[kTokenTableStart + 1].
const intptr_t token_id = Symbols::kTokenTableStart + 1 + tok_index;
ASSERT(symbol_handles_[token_id] != NULL);
return *symbol_handles_[token_id];
}
void Symbols::Init(Isolate* vm_isolate) {
// Should only be run by the vm isolate.
ASSERT(Isolate::Current() == Dart::vm_isolate());
ASSERT(vm_isolate == Dart::vm_isolate());
Zone* zone = Thread::Current()->zone();
// Create and setup a symbol table in the vm isolate.
SetupSymbolTable(vm_isolate);
// Create all predefined symbols.
ASSERT((sizeof(names) / sizeof(const char*)) == Symbols::kNullCharId);
SymbolTable table(zone, vm_isolate->object_store()->symbol_table());
// First set up all the predefined string symbols.
// Create symbols for language keywords. Some keywords are equal to
// symbols we already created, so use New() instead of Add() to ensure
// that the symbols are canonicalized.
for (intptr_t i = 1; i < Symbols::kNullCharId; i++) {
String* str = String::ReadOnlyHandle();
*str = OneByteString::New(names[i], Heap::kOld);
str->Hash();
*str ^= table.InsertOrGet(*str);
str->SetCanonical(); // Make canonical once entered.
symbol_handles_[i] = str;
}
// Add Latin1 characters as Symbols, so that Symbols::FromCharCode is fast.
for (intptr_t c = 0; c < kNumberOfOneCharCodeSymbols; c++) {
intptr_t idx = (kNullCharId + c);
ASSERT(idx < kMaxPredefinedId);
ASSERT(Utf::IsLatin1(c));
uint8_t ch = static_cast<uint8_t>(c);
String* str = String::ReadOnlyHandle();
*str = OneByteString::New(&ch, 1, Heap::kOld);
str->Hash();
*str ^= table.InsertOrGet(*str);
ASSERT(predefined_[c] == NULL);
str->SetCanonical(); // Make canonical once entered.
predefined_[c] = str->raw();
symbol_handles_[idx] = str;
}
vm_isolate->object_store()->set_symbol_table(table.Release());
}
void Symbols::InitFromSnapshot(Isolate* vm_isolate) {
// Should only be run by the vm isolate.
ASSERT(Isolate::Current() == Dart::vm_isolate());
ASSERT(vm_isolate == Dart::vm_isolate());
Zone* zone = Thread::Current()->zone();
SymbolTable table(zone, vm_isolate->object_store()->symbol_table());
// Lookup all the predefined string symbols and language keyword symbols
// and cache them in the read only handles for fast access.
for (intptr_t i = 1; i < Symbols::kNullCharId; i++) {
String* str = String::ReadOnlyHandle();
const unsigned char* name =
reinterpret_cast<const unsigned char*>(names[i]);
*str ^= table.GetOrNull(Latin1Array(name, strlen(names[i])));
ASSERT(!str->IsNull());
ASSERT(str->HasHash());
ASSERT(str->IsCanonical());
symbol_handles_[i] = str;
}
// Lookup Latin1 character Symbols and cache them in read only handles,
// so that Symbols::FromCharCode is fast.
for (intptr_t c = 0; c < kNumberOfOneCharCodeSymbols; c++) {
intptr_t idx = (kNullCharId + c);
ASSERT(idx < kMaxPredefinedId);
ASSERT(Utf::IsLatin1(c));
uint8_t ch = static_cast<uint8_t>(c);
String* str = String::ReadOnlyHandle();
*str ^= table.GetOrNull(Latin1Array(&ch, 1));
ASSERT(!str->IsNull());
ASSERT(str->HasHash());
ASSERT(str->IsCanonical());
predefined_[c] = str->raw();
symbol_handles_[idx] = str;
}
vm_isolate->object_store()->set_symbol_table(table.Release());
}
void Symbols::SetupSymbolTable(Isolate* isolate) {
ASSERT(isolate != NULL);
// Setup the symbol table used within the String class.
const intptr_t initial_size = (isolate == Dart::vm_isolate())
? kInitialVMIsolateSymtabSize
: kInitialSymtabSize;
Array& array =
Array::Handle(HashTables::New<SymbolTable>(initial_size, Heap::kOld));
isolate->object_store()->set_symbol_table(array);
}
RawArray* Symbols::UnifiedSymbolTable() {
Thread* thread = Thread::Current();
Isolate* isolate = thread->isolate();
Zone* zone = thread->zone();
ASSERT(thread->IsMutatorThread());
SymbolTable vm_table(zone,
Dart::vm_isolate()->object_store()->symbol_table());
SymbolTable table(zone, isolate->object_store()->symbol_table());
intptr_t unified_size = vm_table.NumOccupied() + table.NumOccupied();
SymbolTable unified_table(
zone, HashTables::New<SymbolTable>(unified_size, Heap::kOld));
String& symbol = String::Handle(zone);
SymbolTable::Iterator vm_iter(&vm_table);
while (vm_iter.MoveNext()) {
symbol ^= vm_table.GetKey(vm_iter.Current());
ASSERT(!symbol.IsNull());
bool present = unified_table.Insert(symbol);
ASSERT(!present);
}
vm_table.Release();
SymbolTable::Iterator iter(&table);
while (iter.MoveNext()) {
symbol ^= table.GetKey(iter.Current());
ASSERT(!symbol.IsNull());
bool present = unified_table.Insert(symbol);
ASSERT(!present);
}
table.Release();
// TODO(30378): The default load factor of 0.75 / 2 burns ~100KB, but
// increasing the load factor regresses Flutter's hot restart time.
// const double kMinLoad = 0.90;
// const double kMaxLoad = 0.90;
// HashTables::EnsureLoadFactor(kMinLoad, kMaxLoad, unified_table);
return unified_table.Release().raw();
}
void Symbols::Compact(Isolate* isolate) {
ASSERT(isolate != Dart::vm_isolate());
Zone* zone = Thread::Current()->zone();
// 1. Drop the symbol table and do a full garbage collection.
isolate->object_store()->set_symbol_table(Object::empty_array());
isolate->heap()->CollectAllGarbage();
// 2. Walk the heap to find surviving symbols.
GrowableArray<String*> symbols;
class SymbolCollector : public ObjectVisitor {
public:
SymbolCollector(Thread* thread, GrowableArray<String*>* symbols)
: symbols_(symbols), zone_(thread->zone()) {}
void VisitObject(RawObject* obj) {
if (obj->IsCanonical() && obj->IsStringInstance()) {
symbols_->Add(&String::ZoneHandle(zone_, String::RawCast(obj)));
}
}
private:
GrowableArray<String*>* symbols_;
Zone* zone_;
};
{
Thread* thread = Thread::Current();
HeapIterationScope iteration(thread);
SymbolCollector visitor(thread, &symbols);
iteration.IterateObjects(&visitor);
}
// 3. Build a new table from the surviving symbols.
Array& array = Array::Handle(
zone, HashTables::New<SymbolTable>(symbols.length() * 4 / 3, Heap::kOld));
SymbolTable table(zone, array.raw());
for (intptr_t i = 0; i < symbols.length(); i++) {
String& symbol = *symbols[i];
ASSERT(symbol.IsString());
ASSERT(symbol.IsCanonical());
bool present = table.Insert(symbol);
ASSERT(!present);
}
isolate->object_store()->set_symbol_table(table.Release());
}
void Symbols::GetStats(Isolate* isolate, intptr_t* size, intptr_t* capacity) {
ASSERT(isolate != NULL);
SymbolTable table(isolate->object_store()->symbol_table());
*size = table.NumOccupied();
*capacity = table.NumEntries();
table.Release();
}
RawString* Symbols::New(Thread* thread, const char* cstr, intptr_t len) {
ASSERT((cstr != NULL) && (len >= 0));
const uint8_t* utf8_array = reinterpret_cast<const uint8_t*>(cstr);
return Symbols::FromUTF8(thread, utf8_array, len);
}
RawString* Symbols::FromUTF8(Thread* thread,
const uint8_t* utf8_array,
intptr_t array_len) {
if (array_len == 0 || utf8_array == NULL) {
return FromLatin1(thread, reinterpret_cast<uint8_t*>(NULL), 0);
}
Utf8::Type type;
intptr_t len = Utf8::CodeUnitCount(utf8_array, array_len, &type);
ASSERT(len != 0);
Zone* zone = thread->zone();
if (type == Utf8::kLatin1) {
uint8_t* characters = zone->Alloc<uint8_t>(len);
Utf8::DecodeToLatin1(utf8_array, array_len, characters, len);
return FromLatin1(thread, characters, len);
}
ASSERT((type == Utf8::kBMP) || (type == Utf8::kSupplementary));
uint16_t* characters = zone->Alloc<uint16_t>(len);
Utf8::DecodeToUTF16(utf8_array, array_len, characters, len);
return FromUTF16(thread, characters, len);
}
RawString* Symbols::FromLatin1(Thread* thread,
const uint8_t* latin1_array,
intptr_t len) {
return NewSymbol(thread, Latin1Array(latin1_array, len));
}
RawString* Symbols::FromUTF16(Thread* thread,
const uint16_t* utf16_array,
intptr_t len) {
return NewSymbol(thread, UTF16Array(utf16_array, len));
}
RawString* Symbols::FromUTF32(Thread* thread,
const int32_t* utf32_array,
intptr_t len) {
return NewSymbol(thread, UTF32Array(utf32_array, len));
}
RawString* Symbols::FromConcat(Thread* thread,
const String& str1,
const String& str2) {
if (str1.Length() == 0) {
return New(thread, str2);
} else if (str2.Length() == 0) {
return New(thread, str1);
} else {
return NewSymbol(thread, ConcatString(str1, str2));
}
}
RawString* Symbols::FromGet(Thread* thread, const String& str) {
return FromConcat(thread, GetterPrefix(), str);
}
RawString* Symbols::FromSet(Thread* thread, const String& str) {
return FromConcat(thread, SetterPrefix(), str);
}
RawString* Symbols::FromDot(Thread* thread, const String& str) {
return FromConcat(thread, str, Dot());
}
// TODO(srdjan): If this becomes performance critical code, consider looking
// up symbol from hash of pieces instead of concatenating them first into
// a string.
RawString* Symbols::FromConcatAll(
Thread* thread,
const GrowableHandlePtrArray<const String>& strs) {
const intptr_t strs_length = strs.length();
GrowableArray<intptr_t> lengths(strs_length);
intptr_t len_sum = 0;
const intptr_t kOneByteChar = 1;
intptr_t char_size = kOneByteChar;
for (intptr_t i = 0; i < strs_length; i++) {
const String& str = strs[i];
const intptr_t str_len = str.Length();
if ((String::kMaxElements - len_sum) < str_len) {
Exceptions::ThrowOOM();
UNREACHABLE();
}
len_sum += str_len;
lengths.Add(str_len);
char_size = Utils::Maximum(char_size, str.CharSize());
}
const bool is_one_byte_string = char_size == kOneByteChar;
Zone* zone = thread->zone();
if (is_one_byte_string) {
uint8_t* buffer = zone->Alloc<uint8_t>(len_sum);
const uint8_t* const orig_buffer = buffer;
for (intptr_t i = 0; i < strs_length; i++) {
NoSafepointScope no_safepoint;
intptr_t str_len = lengths[i];
if (str_len > 0) {
const String& str = strs[i];
ASSERT(str.IsOneByteString() || str.IsExternalOneByteString());
const uint8_t* src_p = str.IsOneByteString()
? OneByteString::DataStart(str)
: ExternalOneByteString::DataStart(str);
memmove(buffer, src_p, str_len);
buffer += str_len;
}
}
ASSERT(len_sum == buffer - orig_buffer);
return Symbols::FromLatin1(thread, orig_buffer, len_sum);
} else {
uint16_t* buffer = zone->Alloc<uint16_t>(len_sum);
const uint16_t* const orig_buffer = buffer;
for (intptr_t i = 0; i < strs_length; i++) {
NoSafepointScope no_safepoint;
intptr_t str_len = lengths[i];
if (str_len > 0) {
const String& str = strs[i];
if (str.IsTwoByteString()) {
memmove(buffer, TwoByteString::DataStart(str), str_len * 2);
} else if (str.IsExternalTwoByteString()) {
memmove(buffer, ExternalTwoByteString::DataStart(str), str_len * 2);
} else {
// One-byte to two-byte string copy.
ASSERT(str.IsOneByteString() || str.IsExternalOneByteString());
const uint8_t* src_p = str.IsOneByteString()
? OneByteString::DataStart(str)
: ExternalOneByteString::DataStart(str);
for (int n = 0; n < str_len; n++) {
buffer[n] = src_p[n];
}
}
buffer += str_len;
}
}
ASSERT(len_sum == buffer - orig_buffer);
return Symbols::FromUTF16(thread, orig_buffer, len_sum);
}
}
// StringType can be StringSlice, ConcatString, or {Latin1,UTF16,UTF32}Array.
template <typename StringType>
RawString* Symbols::NewSymbol(Thread* thread, const StringType& str) {
REUSABLE_OBJECT_HANDLESCOPE(thread);
REUSABLE_SMI_HANDLESCOPE(thread);
REUSABLE_ARRAY_HANDLESCOPE(thread);
String& symbol = String::Handle(thread->zone());
dart::Object& key = thread->ObjectHandle();
Smi& value = thread->SmiHandle();
Array& data = thread->ArrayHandle();
{
Isolate* vm_isolate = Dart::vm_isolate();
data ^= vm_isolate->object_store()->symbol_table();
SymbolTable table(&key, &value, &data);
symbol ^= table.GetOrNull(str);
table.Release();
}
if (symbol.IsNull()) {
Isolate* isolate = thread->isolate();
SafepointMutexLocker ml(isolate->symbols_mutex());
data ^= isolate->object_store()->symbol_table();
SymbolTable table(&key, &value, &data);
symbol ^= table.InsertNewOrGet(str);
isolate->object_store()->set_symbol_table(table.Release());
}
ASSERT(symbol.IsSymbol());
ASSERT(symbol.HasHash());
return symbol.raw();
}
template <typename StringType>
RawString* Symbols::Lookup(Thread* thread, const StringType& str) {
REUSABLE_OBJECT_HANDLESCOPE(thread);
REUSABLE_SMI_HANDLESCOPE(thread);
REUSABLE_ARRAY_HANDLESCOPE(thread);
String& symbol = String::Handle(thread->zone());
dart::Object& key = thread->ObjectHandle();
Smi& value = thread->SmiHandle();
Array& data = thread->ArrayHandle();
{
Isolate* vm_isolate = Dart::vm_isolate();
data ^= vm_isolate->object_store()->symbol_table();
SymbolTable table(&key, &value, &data);
symbol ^= table.GetOrNull(str);
table.Release();
}
if (symbol.IsNull()) {
Isolate* isolate = thread->isolate();
SafepointMutexLocker ml(isolate->symbols_mutex());
data ^= isolate->object_store()->symbol_table();
SymbolTable table(&key, &value, &data);
symbol ^= table.GetOrNull(str);
table.Release();
}
ASSERT(symbol.IsNull() || symbol.IsSymbol());
ASSERT(symbol.IsNull() || symbol.HasHash());
return symbol.raw();
}
RawString* Symbols::LookupFromConcat(Thread* thread,
const String& str1,
const String& str2) {
if (str1.Length() == 0) {
return Lookup(thread, str2);
} else if (str2.Length() == 0) {
return Lookup(thread, str1);
} else {
return Lookup(thread, ConcatString(str1, str2));
}
}
RawString* Symbols::LookupFromGet(Thread* thread, const String& str) {
return LookupFromConcat(thread, GetterPrefix(), str);
}
RawString* Symbols::LookupFromSet(Thread* thread, const String& str) {
return LookupFromConcat(thread, SetterPrefix(), str);
}
RawString* Symbols::LookupFromDot(Thread* thread, const String& str) {
return LookupFromConcat(thread, str, Dot());
}
RawString* Symbols::New(Thread* thread, const String& str) {
if (str.IsSymbol()) {
return str.raw();
}
return New(thread, str, 0, str.Length());
}
RawString* Symbols::New(Thread* thread,
const String& str,
intptr_t begin_index,
intptr_t len) {
return NewSymbol(thread, StringSlice(str, begin_index, len));
}
RawString* Symbols::NewFormatted(Thread* thread, const char* format, ...) {
va_list args;
va_start(args, format);
RawString* result = NewFormattedV(thread, format, args);
NoSafepointScope no_safepoint;
va_end(args);
return result;
}
RawString* Symbols::NewFormattedV(Thread* thread,
const char* format,
va_list args) {
va_list args_copy;
va_copy(args_copy, args);
intptr_t len = Utils::VSNPrint(NULL, 0, format, args_copy);
va_end(args_copy);
Zone* zone = Thread::Current()->zone();
char* buffer = zone->Alloc<char>(len + 1);
Utils::VSNPrint(buffer, (len + 1), format, args);
return Symbols::New(thread, buffer);
}
RawString* Symbols::FromCharCode(Thread* thread, int32_t char_code) {
if (char_code > kMaxOneCharCodeSymbol) {
return FromUTF32(thread, &char_code, 1);
}
return predefined_[char_code];
}
void Symbols::DumpStats(Isolate* isolate) {
intptr_t size = -1;
intptr_t capacity = -1;
// First dump VM symbol table stats.
GetStats(Dart::vm_isolate(), &size, &capacity);
OS::PrintErr("VM Isolate: Number of symbols : %" Pd "\n", size);
OS::PrintErr("VM Isolate: Symbol table capacity : %" Pd "\n", capacity);
// Now dump regular isolate symbol table stats.
GetStats(isolate, &size, &capacity);
OS::PrintErr("Isolate: Number of symbols : %" Pd "\n", size);
OS::PrintErr("Isolate: Symbol table capacity : %" Pd "\n", capacity);
// TODO(koda): Consider recording growth and collision stats in HashTable,
// in DEBUG mode.
}
intptr_t Symbols::LookupPredefinedSymbol(RawObject* obj) {
for (intptr_t i = 1; i < Symbols::kMaxPredefinedId; i++) {
if (symbol_handles_[i]->raw() == obj) {
return (i + kMaxPredefinedObjectIds);
}
}
return kInvalidIndex;
}
RawObject* Symbols::GetPredefinedSymbol(intptr_t object_id) {
ASSERT(IsPredefinedSymbolId(object_id));
intptr_t i = (object_id - kMaxPredefinedObjectIds);
if ((i > kIllegal) && (i < Symbols::kMaxPredefinedId)) {
return symbol_handles_[i]->raw();
}
return Object::null();
}
} // namespace dart