foundationdb/flow/flow.cpp

750 lines
22 KiB
C++

/*
* flow.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "flow/flow.h"
#include <stdarg.h>
#include <cinttypes>
#include <openssl/err.h>
#include <openssl/rand.h>
#include <fmt/format.h>
#include "flow/DeterministicRandom.h"
#include "flow/Error.h"
#include "flow/Hostname.h"
#include "flow/rte_memcpy.h"
#include "flow/UnitTest.h"
#ifdef WITH_FOLLY_MEMCPY
#include "folly_memcpy.h"
#endif
std::atomic<bool> startSampling = false;
LineageReference rootLineage;
thread_local LineageReference* currentLineage = &rootLineage;
LineagePropertiesBase::~LineagePropertiesBase() {}
#ifdef ENABLE_SAMPLING
ActorLineage::ActorLineage() : properties(), parent(*currentLineage) {}
#else
ActorLineage::ActorLineage() : properties() {}
#endif
ActorLineage::~ActorLineage() {
for (auto property : properties) {
delete property.properties;
}
}
#ifdef ENABLE_SAMPLING
LineageReference getCurrentLineage() {
if (!currentLineage->isValid() || !currentLineage->isAllocated()) {
currentLineage->allocate();
}
return *currentLineage;
}
void sample(LineageReference* lineagePtr);
void replaceLineage(LineageReference* lineage) {
if (!startSampling) {
currentLineage = lineage;
} else {
startSampling = false;
sample(currentLineage);
currentLineage = lineage;
}
}
#endif
using namespace std::literals;
const std::string_view StackLineage::name = "StackLineage"sv;
#if (defined(__linux__) || defined(__FreeBSD__)) && defined(__AVX__) && !defined(MEMORY_SANITIZER) && !DEBUG_DETERMINISM
// For benchmarking; need a version of rte_memcpy that doesn't live in the same compilation unit as the test.
void* rte_memcpy_noinline(void* __restrict __dest, const void* __restrict __src, size_t __n) {
return rte_memcpy(__dest, __src, __n);
}
// This compilation unit will be linked in to the main binary, so this should override glibc memcpy
__attribute__((visibility("default"))) void* memcpy(void* __restrict __dest, const void* __restrict __src, size_t __n) {
// folly_memcpy is faster for small copies, but rte seems to win out in most other circumstances
return rte_memcpy(__dest, __src, __n);
}
#else
void* rte_memcpy_noinline(void* __restrict __dest, const void* __restrict __src, size_t __n) {
return memcpy(__dest, __src, __n);
}
#endif // (defined (__linux__) || defined (__FreeBSD__)) && defined(__AVX__) && !defined(MEMORY_SANITIZER)
INetwork* g_network = nullptr;
FILE* randLog = nullptr;
thread_local Reference<IRandom> seededRandom;
Reference<IRandom> seededDebugRandom;
uint64_t debug_lastLoadBalanceResultEndpointToken = 0;
bool noUnseed = false;
void setThreadLocalDeterministicRandomSeed(uint32_t seed) {
seededRandom = Reference<IRandom>(new DeterministicRandom(seed, true));
seededDebugRandom = Reference<IRandom>(new DeterministicRandom(seed));
}
Reference<IRandom> debugRandom() {
return seededDebugRandom;
}
Reference<IRandom> deterministicRandom() {
if (!seededRandom) {
seededRandom = Reference<IRandom>(new DeterministicRandom(platform::getRandomSeed(), true));
}
return seededRandom;
}
Reference<IRandom> nondeterministicRandom() {
static thread_local Reference<IRandom> random;
if (!random) {
random = Reference<IRandom>(new DeterministicRandom(platform::getRandomSeed()));
}
return random;
}
std::string UID::toString() const {
return fmt::format("{:016x}{:016x}", part[0], part[1]);
}
UID UID::fromString(std::string const& s) {
ASSERT(s.size() == 32);
uint64_t a = 0, b = 0;
int r = sscanf(s.c_str(), "%16" SCNx64 "%16" SCNx64, &a, &b);
ASSERT(r == 2);
return UID(a, b);
}
UID UID::fromStringThrowsOnFailure(std::string const& s) {
if (s.size() != 32) {
// invalid string size
throw operation_failed();
}
uint64_t a = 0, b = 0;
int r = sscanf(s.c_str(), "%16" SCNx64 "%16" SCNx64, &a, &b);
if (r != 2) {
throw operation_failed();
}
return UID(a, b);
}
std::string UID::shortString() const {
return format("%016llx", part[0]);
}
void detectFailureAfter(int const& address, double const& delay);
Optional<uint64_t> parse_with_suffix(std::string const& toparse, std::string const& default_unit) {
char* endptr;
uint64_t ret = strtoull(toparse.c_str(), &endptr, 10);
if (endptr == toparse.c_str()) {
return Optional<uint64_t>();
}
std::string unit;
if (*endptr == '\0') {
if (!default_unit.empty()) {
unit = default_unit;
} else {
return Optional<uint64_t>();
}
} else {
unit = endptr;
}
if (!unit.compare("B")) {
// Nothing to do
} else if (!unit.compare("KB")) {
ret *= int64_t(1e3);
} else if (!unit.compare("KiB")) {
ret *= 1LL << 10;
} else if (!unit.compare("MB")) {
ret *= int64_t(1e6);
} else if (!unit.compare("MiB")) {
ret *= 1LL << 20;
} else if (!unit.compare("GB")) {
ret *= int64_t(1e9);
} else if (!unit.compare("GiB")) {
ret *= 1LL << 30;
} else if (!unit.compare("TB")) {
ret *= int64_t(1e12);
} else if (!unit.compare("TiB")) {
ret *= 1LL << 40;
} else {
return Optional<uint64_t>();
}
return ret;
}
// Parses a duration with one of the following suffixes and returns the duration in seconds
// s - seconds
// m - minutes
// h - hours
// d - days
Optional<uint64_t> parseDuration(std::string const& str, std::string const& defaultUnit) {
char* endptr;
uint64_t ret = strtoull(str.c_str(), &endptr, 10);
if (endptr == str.c_str()) {
return Optional<uint64_t>();
}
std::string unit;
if (*endptr == '\0') {
if (!defaultUnit.empty()) {
unit = defaultUnit;
} else {
return Optional<uint64_t>();
}
} else {
unit = endptr;
}
if (!unit.compare("s")) {
// Nothing to do
} else if (!unit.compare("m")) {
ret *= 60;
} else if (!unit.compare("h")) {
ret *= 60 * 60;
} else if (!unit.compare("d")) {
ret *= 24 * 60 * 60;
} else {
return Optional<uint64_t>();
}
return ret;
}
int vsformat(std::string& outputString, const char* form, va_list args) {
char buf[200];
va_list args2;
va_copy(args2, args);
int size = vsnprintf(buf, sizeof(buf), form, args2);
va_end(args2);
if (size >= 0 && size < sizeof(buf)) {
outputString = std::string(buf, size);
return size;
}
#ifdef _WIN32
// Microsoft's non-standard vsnprintf doesn't return a correct size, but just an error, so determine the necessary
// size
va_copy(args2, args);
size = _vscprintf(form, args2);
va_end(args2);
#endif
if (size < 0) {
return -1;
}
CODE_PROBE(true, "large format result");
outputString.resize(size + 1);
size = vsnprintf(&outputString[0], outputString.size(), form, args);
if (size < 0 || size >= outputString.size()) {
return -1;
}
outputString.resize(size);
return size;
}
std::string format(const char* form, ...) {
va_list args;
va_start(args, form);
std::string str;
int result = vsformat(str, form, args);
va_end(args);
ASSERT(result >= 0);
return str;
}
Standalone<StringRef> strinc(StringRef const& str) {
int index;
for (index = str.size() - 1; index >= 0; index--)
if (str[index] != 255)
break;
// Must not be called with a string that consists only of zero or more '\xff' bytes.
ASSERT(index >= 0);
Standalone<StringRef> r = str.substr(0, index + 1);
uint8_t* p = mutateString(r);
p[r.size() - 1]++;
return r;
}
StringRef strinc(StringRef const& str, Arena& arena) {
int index;
for (index = str.size() - 1; index >= 0; index--)
if (str[index] != 255)
break;
// Must not be called with a string that consists only of zero or more '\xff' bytes.
ASSERT(index >= 0);
StringRef r(arena, str.substr(0, index + 1));
uint8_t* p = mutateString(r);
p[r.size() - 1]++;
return r;
}
StringRef addVersionStampAtEnd(StringRef const& str, Arena& arena) {
int32_t size = str.size();
uint8_t* s = new (arena) uint8_t[size + 14];
memcpy(s, str.begin(), size);
memset(&s[size], 0, 10);
memcpy(&s[size + 10], &size, 4);
return StringRef(s, size + 14);
}
Standalone<StringRef> addVersionStampAtEnd(StringRef const& str) {
Standalone<StringRef> r;
((StringRef&)r) = addVersionStampAtEnd(str, r.arena());
return r;
}
namespace {
std::vector<bool> buggifyActivated{ false, false };
std::map<BuggifyType, std::map<std::pair<std::string, int>, int>> typedSBVars;
} // namespace
std::vector<double> P_BUGGIFIED_SECTION_ACTIVATED{ .25, .25 };
std::vector<double> P_BUGGIFIED_SECTION_FIRES{ .25, .25 };
double P_EXPENSIVE_VALIDATION = .05;
int getSBVar(std::string const& file, int line, BuggifyType type) {
if (!buggifyActivated[int(type)])
return 0;
const auto& flPair = std::make_pair(file, line);
auto& SBVars = typedSBVars[type];
if (!SBVars.count(flPair)) {
SBVars[flPair] = deterministicRandom()->random01() < P_BUGGIFIED_SECTION_ACTIVATED[int(type)];
g_traceBatch.addBuggify(SBVars[flPair], line, file);
if (g_network)
g_traceBatch.dump();
}
return SBVars[flPair];
}
void clearBuggifySections(BuggifyType type) {
typedSBVars[type].clear();
}
bool validationIsEnabled(BuggifyType type) {
return buggifyActivated[int(type)];
}
bool isBuggifyEnabled(BuggifyType type) {
return buggifyActivated[int(type)];
}
void enableBuggify(bool enabled, BuggifyType type) {
buggifyActivated[int(type)] = enabled;
}
// Make OpenSSL use DeterministicRandom as RNG source such that simulation runs stay deterministic w/ e.g. signature ops
void bindDeterministicRandomToOpenssl() {
// TODO: implement ifdef branch for 3.x using provider API
#ifndef OPENSSL_IS_BORINGSSL
static const RAND_METHOD method = {
// replacement for RAND_seed(), which reseeds OpenSSL RNG
[](const void*, int) -> int { return 1; },
// replacement for RAND_bytes(), which fills given buffer with random byte sequence
[](unsigned char* buf, int length) -> int {
if (g_network)
ASSERT_ABORT(g_network->isSimulated());
deterministicRandom()->randomBytes(buf, length);
return 1;
},
// replacement for RAND_cleanup(), a no-op for simulation
[]() -> void {},
// replacement for RAND_add(), which reseeds OpenSSL RNG with randomness hint
[](const void*, int, double) -> int { return 1; },
// replacement for default pseudobytes getter (same as RAND_bytes by default)
[](unsigned char* buf, int length) -> int {
if (g_network)
ASSERT_ABORT(g_network->isSimulated());
deterministicRandom()->randomBytes(buf, length);
return 1;
},
// status function for PRNG readiness check
[]() -> int { return 1; },
};
if (1 != ::RAND_set_rand_method(&method)) {
auto ec = ::ERR_get_error();
char msg[256]{
0,
};
if (ec) {
::ERR_error_string_n(ec, msg, sizeof(msg));
}
fprintf(stderr,
"ERROR: Failed to bind DeterministicRandom to OpenSSL RNG\n"
" OpenSSL error message: '%s'\n",
msg);
throw internal_error();
} else {
printf("DeterministicRandom successfully bound to OpenSSL RNG\n");
}
#else // OPENSSL_IS_BORINGSSL
static const RAND_METHOD method = {
[](const void*, int) -> void {},
[](unsigned char* buf, unsigned long length) -> int {
if (g_network)
ASSERT_ABORT(g_network->isSimulated());
ASSERT(length <= std::numeric_limits<int>::max());
deterministicRandom()->randomBytes(buf, length);
return 1;
},
[]() -> void {},
[](const void*, int, double) -> void {},
[](unsigned char* buf, unsigned long length) -> int {
if (g_network)
ASSERT_ABORT(g_network->isSimulated());
ASSERT(length <= std::numeric_limits<int>::max());
deterministicRandom()->randomBytes(buf, length);
return 1;
},
[]() -> int { return 1; },
};
::RAND_set_rand_method(&method);
printf("DeterministicRandom successfully bound to OpenSSL RNG\n");
#endif // OPENSSL_IS_BORINGSSL
}
int nChooseK(int n, int k) {
assert(n >= k && k >= 0);
if (k == 0) {
return 1;
}
if (k > n / 2) {
return nChooseK(n, n - k);
}
long ret = 1;
// To avoid integer overflow, we do n/1 * (n-1)/2 * (n-2)/3 * (n-i+1)/i, where i = k
for (int i = 1; i <= k; ++i) {
ret *= n - i + 1;
ret /= i;
}
ASSERT(ret <= INT_MAX);
return ret;
}
namespace {
// Simple message for flatbuffers unittests
struct Int {
constexpr static FileIdentifier file_identifier = 12345;
uint32_t value;
Int() = default;
Int(uint32_t value) : value(value) {}
template <class Ar>
void serialize(Ar& ar) {
serializer(ar, value);
}
};
} // namespace
TEST_CASE("/flow/FlatBuffers/ErrorOr") {
{
ErrorOr<Int> in(worker_removed());
ErrorOr<Int> out;
ObjectWriter writer(Unversioned());
writer.serialize(in);
Standalone<StringRef> copy = writer.toStringRef();
ArenaObjectReader reader(copy.arena(), copy, Unversioned());
reader.deserialize(out);
ASSERT(out.isError());
ASSERT(out.getError().code() == in.getError().code());
}
{
ErrorOr<Int> in(deterministicRandom()->randomUInt32());
ErrorOr<Int> out;
ObjectWriter writer(Unversioned());
writer.serialize(in);
Standalone<StringRef> copy = writer.toStringRef();
ArenaObjectReader reader(copy.arena(), copy, Unversioned());
reader.deserialize(out);
ASSERT(!out.isError());
ASSERT(out.get().value == in.get().value);
}
return Void();
}
TEST_CASE("/flow/FlatBuffers/Optional") {
{
Optional<Int> in;
Optional<Int> out;
ObjectWriter writer(Unversioned());
writer.serialize(in);
Standalone<StringRef> copy = writer.toStringRef();
ArenaObjectReader reader(copy.arena(), copy, Unversioned());
reader.deserialize(out);
ASSERT(!out.present());
}
{
Optional<Int> in(deterministicRandom()->randomUInt32());
Optional<Int> out;
ObjectWriter writer(Unversioned());
writer.serialize(in);
Standalone<StringRef> copy = writer.toStringRef();
ArenaObjectReader reader(copy.arena(), copy, Unversioned());
reader.deserialize(out);
ASSERT(out.present());
ASSERT(out.get().value == in.get().value);
}
return Void();
}
TEST_CASE("/flow/FlatBuffers/Standalone") {
{
Standalone<StringRef> in(std::string("foobar"));
StringRef out;
ObjectWriter writer(Unversioned());
writer.serialize(in);
Standalone<StringRef> copy = writer.toStringRef();
ArenaObjectReader reader(copy.arena(), copy, Unversioned());
reader.deserialize(out);
ASSERT(in == out);
}
{
StringRef in = "foobar"_sr;
Standalone<StringRef> out;
ObjectWriter writer(Unversioned());
writer.serialize(in);
Standalone<StringRef> copy = writer.toStringRef();
ArenaObjectReader reader(copy.arena(), copy, Unversioned());
reader.deserialize(out);
ASSERT(in == out);
}
return Void();
}
// we need to make sure at least one test of each prefix exists, otherwise
// the noSim test fails if we compile without RocksDB
TEST_CASE("noSim/noopTest") {
return Void();
}
struct TestErrorOrMapClass {
StringRef value;
ErrorOr<StringRef> errorOrValue;
const StringRef constValue;
const ErrorOr<StringRef> constErrorOrValue;
StringRef getValue() const { return value; }
ErrorOr<StringRef> getErrorOrValue() const { return errorOrValue; }
StringRef const& getValueRef() const { return value; }
ErrorOr<StringRef> const& getErrorOrValueRef() const { return errorOrValue; }
StringRef sub(int x) const { return value.substr(x); }
ErrorOr<StringRef> errorOrSub(int x) const { return errorOrValue.map<StringRef>(&StringRef::substr, (int)x); }
TestErrorOrMapClass(StringRef value, Optional<Error> optionalValueError)
: value(value), constValue(value),
errorOrValue(!optionalValueError.present() ? ErrorOr<StringRef>(value)
: ErrorOr<StringRef>(optionalValueError.get())),
constErrorOrValue(!optionalValueError.present() ? ErrorOr<StringRef>(value)
: ErrorOr<StringRef>(optionalValueError.get())) {}
};
struct TestErrorOrMapClassRef : public TestErrorOrMapClass, public ReferenceCounted<TestErrorOrMapClassRef> {
TestErrorOrMapClassRef(StringRef value, Optional<Error> optionalValueError)
: TestErrorOrMapClass(value, optionalValueError) {}
};
void checkResults(std::vector<ErrorOr<StringRef>> const& results,
StringRef value,
Optional<Error> expectedError,
std::string context) {
if (expectedError.present()) {
for (int i = 0; i < results.size(); ++i) {
if (results[i].present() || results[i].getError().code() != expectedError.get().code()) {
fmt::print("Unexpected result at index {} in {}\n", i, context);
ASSERT(false);
}
}
} else {
for (int i = 0; i < results.size(); ++i) {
if (!results[i].present()) {
fmt::print("Missing result {} at index {} in {}\n", value.printable(), i, context);
ASSERT(false);
}
if (i < results.size() - 1) {
if (results[i].get() != value) {
fmt::print("Incorrect result {} at index {} in {}: expected {}\n",
results[i].get().printable(),
i,
context,
value.printable());
ASSERT(false);
}
} else {
if (results[i].get() != value.substr(5)) {
fmt::print("Incorrect result {} at index {} in {}: expected {}\n",
results[i].get().printable(),
i,
context,
value.substr(5).printable());
ASSERT(false);
}
}
}
}
}
template <bool IsRef, class T>
void checkErrorOr(ErrorOr<T> val) {
StringRef value;
bool isError = !val.present();
bool isFlatMapError = isError;
Optional<Error> expectedError;
std::vector<ErrorOr<StringRef>> mapResults;
std::vector<ErrorOr<StringRef>> flatMapResults;
if (isError) {
expectedError = val.getError();
}
if constexpr (IsRef) {
if (!isError && !val.get()) {
isError = isFlatMapError = true;
expectedError = default_error_or();
}
if (!isError) {
value = val.get()->value;
isFlatMapError = !val.get()->errorOrValue.present();
if (isFlatMapError) {
expectedError = val.get()->errorOrValue.getError();
}
}
mapResults.push_back(val.mapRef(&TestErrorOrMapClass::value));
mapResults.push_back(val.mapRef(&TestErrorOrMapClass::constValue));
mapResults.push_back(val.mapRef(&TestErrorOrMapClass::getValue));
mapResults.push_back(val.mapRef(&TestErrorOrMapClass::getValueRef));
mapResults.push_back(val.mapRef(&TestErrorOrMapClass::sub, 5));
flatMapResults.push_back(val.flatMap([](auto t) { return t ? t->errorOrValue : ErrorOr<StringRef>(); }));
flatMapResults.push_back(val.flatMapRef(&TestErrorOrMapClass::errorOrValue));
flatMapResults.push_back(val.flatMapRef(&TestErrorOrMapClass::constErrorOrValue));
flatMapResults.push_back(val.flatMapRef(&TestErrorOrMapClass::getErrorOrValue));
flatMapResults.push_back(val.flatMapRef(&TestErrorOrMapClass::getErrorOrValueRef));
flatMapResults.push_back(val.flatMapRef(&TestErrorOrMapClass::errorOrSub, 5));
} else {
if (!isError) {
value = val.get().value;
isFlatMapError = !val.get().errorOrValue.present();
if (isFlatMapError) {
expectedError = val.get().errorOrValue.getError();
}
}
mapResults.push_back(val.map([](auto t) { return t.value; }));
mapResults.push_back(val.map(&TestErrorOrMapClass::value));
mapResults.push_back(val.map(&TestErrorOrMapClass::constValue));
mapResults.push_back(val.map(&TestErrorOrMapClass::getValue));
mapResults.push_back(val.map(&TestErrorOrMapClass::getValueRef));
mapResults.push_back(val.map(&TestErrorOrMapClass::sub, 5));
flatMapResults.push_back(val.flatMap([](auto t) { return t.errorOrValue; }));
flatMapResults.push_back(val.flatMap(&TestErrorOrMapClass::errorOrValue));
flatMapResults.push_back(val.flatMap(&TestErrorOrMapClass::constErrorOrValue));
flatMapResults.push_back(val.flatMap(&TestErrorOrMapClass::getErrorOrValue));
flatMapResults.push_back(val.flatMap(&TestErrorOrMapClass::getErrorOrValueRef));
flatMapResults.push_back(val.flatMap(&TestErrorOrMapClass::errorOrSub, 5));
}
checkResults(mapResults, value, isError ? expectedError : Optional<Error>(), IsRef ? "ref map" : "non-ref map");
checkResults(flatMapResults,
value,
isFlatMapError ? expectedError : Optional<Error>(),
IsRef ? "ref flat map" : "non-ref flat map");
}
TEST_CASE("/flow/ErrorOr/Map") {
// ErrorOr<T>
checkErrorOr<false>(ErrorOr<TestErrorOrMapClass>());
checkErrorOr<false>(ErrorOr<TestErrorOrMapClass>(transaction_too_old()));
checkErrorOr<false>(ErrorOr<TestErrorOrMapClass>(TestErrorOrMapClass("test_string"_sr, {})));
checkErrorOr<false>(ErrorOr<TestErrorOrMapClass>(TestErrorOrMapClass("test_string"_sr, default_error_or())));
checkErrorOr<false>(ErrorOr<TestErrorOrMapClass>(TestErrorOrMapClass("test_string"_sr, transaction_too_old())));
// ErrorOr<Reference<T>>
checkErrorOr<true>(ErrorOr<Reference<TestErrorOrMapClassRef>>());
checkErrorOr<true>(ErrorOr<Reference<TestErrorOrMapClassRef>>(Reference<TestErrorOrMapClassRef>()));
checkErrorOr<true>(ErrorOr<Reference<TestErrorOrMapClassRef>>(transaction_too_old()));
checkErrorOr<true>(ErrorOr<Reference<TestErrorOrMapClassRef>>(
makeReference<TestErrorOrMapClassRef>("test_string"_sr, Optional<Error>())));
checkErrorOr<true>(ErrorOr<Reference<TestErrorOrMapClassRef>>(
makeReference<TestErrorOrMapClassRef>("test_string"_sr, Optional<Error>(default_error_or()))));
checkErrorOr<true>(ErrorOr<Reference<TestErrorOrMapClassRef>>(
makeReference<TestErrorOrMapClassRef>("test_string"_sr, Optional<Error>(transaction_too_old()))));
// ErrorOr<T*>
checkErrorOr<true>(ErrorOr<TestErrorOrMapClass*>());
checkErrorOr<true>(ErrorOr<TestErrorOrMapClass*>(nullptr));
checkErrorOr<true>(ErrorOr<TestErrorOrMapClassRef*>(transaction_too_old()));
auto ptr = new TestErrorOrMapClass("test_string"_sr, Optional<Error>());
checkErrorOr<true>(ErrorOr<TestErrorOrMapClass*>(ptr));
delete ptr;
ptr = new TestErrorOrMapClass("test_string"_sr, default_error_or());
checkErrorOr<true>(ErrorOr<TestErrorOrMapClass*>(ptr));
delete ptr;
ptr = new TestErrorOrMapClass("test_string"_sr, transaction_too_old());
checkErrorOr<true>(ErrorOr<TestErrorOrMapClass*>(ptr));
delete ptr;
return Void();
}