/*
- * Copyright 2015 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <folly/Singleton.h>
+#ifndef _WIN32
+#include <dlfcn.h>
+#endif
+
#include <atomic>
+#include <cstdio>
+#include <cstdlib>
+#include <iostream>
#include <string>
#include <folly/ScopeGuard.h>
+#if !defined(_WIN32) && !defined(__APPLE__) && !defined(__ANDROID__)
+static void hs_init_weak(int* argc, char** argv[])
+ __attribute__((__weakref__("hs_init")));
+#endif
+
namespace folly {
-namespace detail {
+SingletonVault::Type SingletonVault::defaultVaultType() {
+#if !defined(_WIN32) && !defined(__APPLE__) && !defined(__ANDROID__)
+ bool isPython = dlsym(RTLD_DEFAULT, "Py_Main");
+ bool isHaskel = &::hs_init_weak || dlsym(RTLD_DEFAULT, "hs_init");
+ bool isJVM = dlsym(RTLD_DEFAULT, "JNI_GetCreatedJavaVMs");
+ bool isD = dlsym(RTLD_DEFAULT, "_d_run_main");
-constexpr std::chrono::seconds SingletonHolderBase::kDestroyWaitTime;
+ return isPython || isHaskel || isJVM || isD ? Type::Relaxed : Type::Strict;
+#else
+ return Type::Relaxed;
+#endif
+}
+namespace detail {
+
+[[noreturn]] void singletonWarnDoubleRegistrationAndAbort(
+ const TypeDescriptor& type) {
+ // Ensure the availability of std::cerr
+ std::ios_base::Init ioInit;
+ std::cerr << "Double registration of singletons of the same "
+ "underlying type; check for multiple definitions "
+ "of type folly::Singleton<"
+ << type.name() << ">\n";
+ std::abort();
+}
}
namespace {
SingletonVault::~SingletonVault() { destroyInstances(); }
void SingletonVault::registerSingleton(detail::SingletonHolderBase* entry) {
- RWSpinLock::ReadHolder rh(&stateMutex_);
+ auto state = state_.rlock();
+ stateCheck(SingletonVaultState::Running, *state);
- stateCheck(SingletonVaultState::Running);
-
- if (UNLIKELY(registrationComplete_)) {
- throw std::logic_error(
- "Registering singleton after registrationComplete().");
+ if (UNLIKELY(state->registrationComplete)) {
+ LOG(ERROR) << "Registering singleton after registrationComplete().";
}
- RWSpinLock::ReadHolder rhMutex(&mutex_);
- CHECK_THROW(singletons_.find(entry->type()) == singletons_.end(),
- std::logic_error);
-
- RWSpinLock::UpgradedHolder wh(&mutex_);
- singletons_[entry->type()] = entry;
+ auto singletons = singletons_.wlock();
+ CHECK_THROW(
+ singletons->emplace(entry->type(), entry).second, std::logic_error);
}
void SingletonVault::addEagerInitSingleton(detail::SingletonHolderBase* entry) {
- RWSpinLock::ReadHolder rh(&stateMutex_);
-
- stateCheck(SingletonVaultState::Running);
+ auto state = state_.rlock();
+ stateCheck(SingletonVaultState::Running, *state);
- if (UNLIKELY(registrationComplete_)) {
- throw std::logic_error(
- "Registering for eager-load after registrationComplete().");
+ if (UNLIKELY(state->registrationComplete)) {
+ LOG(ERROR) << "Registering for eager-load after registrationComplete().";
}
- RWSpinLock::ReadHolder rhMutex(&mutex_);
- CHECK_THROW(singletons_.find(entry->type()) != singletons_.end(),
- std::logic_error);
+ CHECK_THROW(singletons_.rlock()->count(entry->type()), std::logic_error);
- RWSpinLock::UpgradedHolder wh(&mutex_);
- eagerInitSingletons_.insert(entry);
+ auto eagerInitSingletons = eagerInitSingletons_.wlock();
+ eagerInitSingletons->insert(entry);
}
void SingletonVault::registrationComplete() {
std::atexit([](){ SingletonVault::singleton()->destroyInstances(); });
- RWSpinLock::WriteHolder wh(&stateMutex_);
+ auto state = state_.wlock();
+ stateCheck(SingletonVaultState::Running, *state);
- stateCheck(SingletonVaultState::Running);
+ if (state->registrationComplete) {
+ return;
+ }
+ auto singletons = singletons_.rlock();
if (type_ == Type::Strict) {
- for (const auto& p : singletons_) {
+ for (const auto& p : *singletons) {
if (p.second->hasLiveInstance()) {
throw std::runtime_error(
- "Singleton created before registration was complete.");
+ "Singleton " + p.first.name() +
+ " created before registration was complete.");
}
}
}
- registrationComplete_ = true;
+ state->registrationComplete = true;
}
void SingletonVault::doEagerInit() {
- std::unordered_set<detail::SingletonHolderBase*> singletonSet;
{
- RWSpinLock::ReadHolder rh(&stateMutex_);
- stateCheck(SingletonVaultState::Running);
- if (UNLIKELY(!registrationComplete_)) {
+ auto state = state_.rlock();
+ stateCheck(SingletonVaultState::Running, *state);
+ if (UNLIKELY(!state->registrationComplete)) {
throw std::logic_error("registrationComplete() not yet called");
}
- singletonSet = eagerInitSingletons_; // copy set of pointers
}
- for (auto *single : singletonSet) {
+ auto eagerInitSingletons = eagerInitSingletons_.rlock();
+ for (auto* single : *eagerInitSingletons) {
single->createInstance();
}
}
void SingletonVault::doEagerInitVia(Executor& exe, folly::Baton<>* done) {
- std::unordered_set<detail::SingletonHolderBase*> singletonSet;
{
- RWSpinLock::ReadHolder rh(&stateMutex_);
- stateCheck(SingletonVaultState::Running);
- if (UNLIKELY(!registrationComplete_)) {
+ auto state = state_.rlock();
+ stateCheck(SingletonVaultState::Running, *state);
+ if (UNLIKELY(!state->registrationComplete)) {
throw std::logic_error("registrationComplete() not yet called");
}
- singletonSet = eagerInitSingletons_; // copy set of pointers
}
- auto countdown = std::make_shared<std::atomic<size_t>>(singletonSet.size());
- for (auto* single : singletonSet) {
+ auto eagerInitSingletons = eagerInitSingletons_.rlock();
+ auto countdown =
+ std::make_shared<std::atomic<size_t>>(eagerInitSingletons->size());
+ for (auto* single : *eagerInitSingletons) {
// countdown is retained by shared_ptr, and will be alive until last lambda
// is done. notifyBaton is provided by the caller, and expected to remain
// present (if it's non-nullptr). singletonSet can go out of scope but
}
void SingletonVault::destroyInstances() {
- RWSpinLock::WriteHolder state_wh(&stateMutex_);
-
- if (state_ == SingletonVaultState::Quiescing) {
+ auto stateW = state_.wlock();
+ if (stateW->state == SingletonVaultState::Quiescing) {
return;
}
- state_ = SingletonVaultState::Quiescing;
-
- RWSpinLock::ReadHolder state_rh(std::move(state_wh));
+ stateW->state = SingletonVaultState::Quiescing;
+ auto stateR = stateW.moveFromWriteToRead();
{
- RWSpinLock::ReadHolder rh(&mutex_);
+ auto singletons = singletons_.rlock();
+ auto creationOrder = creationOrder_.rlock();
- CHECK_GE(singletons_.size(), creation_order_.size());
+ CHECK_GE(singletons->size(), creationOrder->size());
- for (auto type_iter = creation_order_.rbegin();
- type_iter != creation_order_.rend();
+ // Release all ReadMostlyMainPtrs at once
+ {
+ ReadMostlyMainPtrDeleter<> deleter;
+ for (auto& singleton_type : *creationOrder) {
+ singletons->at(singleton_type)->preDestroyInstance(deleter);
+ }
+ }
+
+ for (auto type_iter = creationOrder->rbegin();
+ type_iter != creationOrder->rend();
++type_iter) {
- singletons_[*type_iter]->destroyInstance();
+ singletons->at(*type_iter)->destroyInstance();
}
- for (auto& singleton_type: creation_order_) {
- auto singleton = singletons_[singleton_type];
+ for (auto& singleton_type : *creationOrder) {
+ auto singleton = singletons->at(singleton_type);
if (!singleton->hasLiveInstance()) {
continue;
}
}
{
- RWSpinLock::WriteHolder wh(&mutex_);
- creation_order_.clear();
+ auto creationOrder = creationOrder_.wlock();
+ creationOrder->clear();
}
}
void SingletonVault::reenableInstances() {
- RWSpinLock::WriteHolder state_wh(&stateMutex_);
+ auto state = state_.wlock();
- stateCheck(SingletonVaultState::Quiescing);
+ stateCheck(SingletonVaultState::Quiescing, *state);
- state_ = SingletonVaultState::Running;
+ state->state = SingletonVaultState::Running;
}
void SingletonVault::scheduleDestroyInstances() {
+ // Add a dependency on folly::ThreadLocal to make sure all its static
+ // singletons are initalized first.
+ threadlocal_detail::StaticMeta<void, void>::instance();
+
class SingletonVaultDestructor {
public:
~SingletonVaultDestructor() {
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