Commit 34986bb4 authored by Chad Parry's avatar Chad Parry Committed by Facebook Github Bot 4

Prevent leaks in ThreadLocalPtr initialization

Summary: While making an unrelated change, (D3271563, which was needed from an unrelated change, (D3237530)), I noticed a lack of exception safety here. If `std::bad_alloc` were thrown, then we don't want to leak memory.

Reviewed By: ericniebler

Differential Revision: D3271911

fbshipit-source-id: 0d316c0fa865a7d64622c1d62160bb0c2b061d78
parent da5b2838
......@@ -36,11 +36,12 @@
#pragma once
#include <folly/Likely.h>
#include <folly/Portability.h>
#include <folly/ScopeGuard.h>
#include <boost/iterator/iterator_facade.hpp>
#include <folly/Likely.h>
#include <type_traits>
#include <utility>
namespace folly {
enum class TLPDestructionMode {
......@@ -180,12 +181,12 @@ class ThreadLocalPtr {
}
void reset(T* newPtr = nullptr) {
auto guard = makeGuard([&] { delete newPtr; });
threadlocal_detail::ElementWrapper& w = StaticMeta::instance().get(&id_);
if (w.ptr != newPtr) {
w.dispose(TLPDestructionMode::THIS_THREAD);
w.set(newPtr);
}
w.dispose(TLPDestructionMode::THIS_THREAD);
guard.dismiss();
w.set(newPtr);
}
explicit operator bool() const {
......@@ -197,15 +198,20 @@ class ThreadLocalPtr {
* deleter(T* ptr, TLPDestructionMode mode)
* "mode" is ALL_THREADS if we're destructing this ThreadLocalPtr (and thus
* deleting pointers for all threads), and THIS_THREAD if we're only deleting
* the member for one thread (because of thread exit or reset())
* the member for one thread (because of thread exit or reset()).
* Invoking the deleter must not throw.
*/
template <class Deleter>
void reset(T* newPtr, Deleter deleter) {
void reset(T* newPtr, const Deleter& deleter) {
auto guard = makeGuard([&] {
if (newPtr) {
deleter(newPtr, TLPDestructionMode::THIS_THREAD);
}
});
threadlocal_detail::ElementWrapper& w = StaticMeta::instance().get(&id_);
if (w.ptr != newPtr) {
w.dispose(TLPDestructionMode::THIS_THREAD);
w.set(newPtr, deleter);
}
w.dispose(TLPDestructionMode::THIS_THREAD);
guard.dismiss();
w.set(newPtr, deleter);
}
// Holds a global lock for iteration through all thread local child objects.
......
......@@ -33,6 +33,7 @@
#include <folly/Malloc.h>
#include <folly/MicroSpinLock.h>
#include <folly/Portability.h>
#include <folly/ScopeGuard.h>
#include <folly/detail/StaticSingletonManager.h>
......@@ -81,6 +82,7 @@ struct ElementWrapper {
template <class Ptr>
void set(Ptr p) {
auto guard = makeGuard([&] { delete p; });
DCHECK(ptr == nullptr);
DCHECK(deleter1 == nullptr);
......@@ -90,20 +92,27 @@ struct ElementWrapper {
delete static_cast<Ptr>(pt);
};
ownsDeleter = false;
guard.dismiss();
}
}
template <class Ptr, class Deleter>
void set(Ptr p, Deleter d) {
void set(Ptr p, const Deleter& d) {
auto guard = makeGuard([&] {
if (p) {
d(p, TLPDestructionMode::THIS_THREAD);
}
});
DCHECK(ptr == nullptr);
DCHECK(deleter2 == nullptr);
if (p) {
ptr = p;
deleter2 = new std::function<DeleterFunType>(
[d](void* pt, TLPDestructionMode mode) {
d(static_cast<Ptr>(pt), mode);
});
deleter2 = new std::function<DeleterFunType>([d = d](
void* pt, TLPDestructionMode mode) {
d(static_cast<Ptr>(pt), mode);
});
ownsDeleter = true;
guard.dismiss();
}
}
......
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