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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/threading/thread_restrictions.h"
#if DCHECK_IS_ON()
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/threading/thread_local.h"
namespace base {
namespace {
LazyInstance<ThreadLocalBoolean>::Leaky g_blocking_disallowed =
LAZY_INSTANCE_INITIALIZER;
LazyInstance<ThreadLocalBoolean>::Leaky
g_singleton_disallowed = LAZY_INSTANCE_INITIALIZER;
LazyInstance<ThreadLocalBoolean>::Leaky g_base_sync_primitives_disallowed =
LAZY_INSTANCE_INITIALIZER;
} // namespace
void AssertBlockingAllowed() {
DCHECK(!g_blocking_disallowed.Get().Get())
<< "Function marked as blocking was called from a scope that disallows "
"blocking! If this task is running inside the TaskScheduler, it needs "
"to have MayBlock() in its TaskTraits. Otherwise, consider making "
"this blocking work asynchronous or, as a last resort, you may use "
"ScopedAllowBlocking in a narrow scope.";
}
void DisallowBlocking() {
g_blocking_disallowed.Get().Set(true);
}
ScopedDisallowBlocking::ScopedDisallowBlocking()
: was_disallowed_(g_blocking_disallowed.Get().Get()) {
g_blocking_disallowed.Get().Set(true);
}
ScopedDisallowBlocking::~ScopedDisallowBlocking() {
DCHECK(g_blocking_disallowed.Get().Get());
g_blocking_disallowed.Get().Set(was_disallowed_);
}
ScopedAllowBlocking::ScopedAllowBlocking()
: was_disallowed_(g_blocking_disallowed.Get().Get()) {
g_blocking_disallowed.Get().Set(false);
}
ScopedAllowBlocking::~ScopedAllowBlocking() {
DCHECK(!g_blocking_disallowed.Get().Get());
g_blocking_disallowed.Get().Set(was_disallowed_);
}
void DisallowBaseSyncPrimitives() {
g_base_sync_primitives_disallowed.Get().Set(true);
}
ScopedAllowBaseSyncPrimitives::ScopedAllowBaseSyncPrimitives()
: was_disallowed_(g_base_sync_primitives_disallowed.Get().Get()) {
DCHECK(!g_blocking_disallowed.Get().Get())
<< "To allow //base sync primitives in a scope where blocking is "
"disallowed use ScopedAllowBaseSyncPrimitivesOutsideBlockingScope.";
g_base_sync_primitives_disallowed.Get().Set(false);
}
ScopedAllowBaseSyncPrimitives::~ScopedAllowBaseSyncPrimitives() {
DCHECK(!g_base_sync_primitives_disallowed.Get().Get());
g_base_sync_primitives_disallowed.Get().Set(was_disallowed_);
}
ScopedAllowBaseSyncPrimitivesOutsideBlockingScope::
ScopedAllowBaseSyncPrimitivesOutsideBlockingScope()
: was_disallowed_(g_base_sync_primitives_disallowed.Get().Get()) {
g_base_sync_primitives_disallowed.Get().Set(false);
}
ScopedAllowBaseSyncPrimitivesOutsideBlockingScope::
~ScopedAllowBaseSyncPrimitivesOutsideBlockingScope() {
DCHECK(!g_base_sync_primitives_disallowed.Get().Get());
g_base_sync_primitives_disallowed.Get().Set(was_disallowed_);
}
ScopedAllowBaseSyncPrimitivesForTesting::
ScopedAllowBaseSyncPrimitivesForTesting()
: was_disallowed_(g_base_sync_primitives_disallowed.Get().Get()) {
g_base_sync_primitives_disallowed.Get().Set(false);
}
ScopedAllowBaseSyncPrimitivesForTesting::
~ScopedAllowBaseSyncPrimitivesForTesting() {
DCHECK(!g_base_sync_primitives_disallowed.Get().Get());
g_base_sync_primitives_disallowed.Get().Set(was_disallowed_);
}
namespace internal {
void AssertBaseSyncPrimitivesAllowed() {
DCHECK(!g_base_sync_primitives_disallowed.Get().Get())
<< "Waiting on a //base sync primitive is not allowed on this thread to "
"prevent jank and deadlock. If waiting on a //base sync primitive is "
"unavoidable, do it within the scope of a "
"ScopedAllowBaseSyncPrimitives. If in a test, "
"use ScopedAllowBaseSyncPrimitivesForTesting.";
}
void ResetThreadRestrictionsForTesting() {
g_blocking_disallowed.Get().Set(false);
g_singleton_disallowed.Get().Set(false);
g_base_sync_primitives_disallowed.Get().Set(false);
}
} // namespace internal
ThreadRestrictions::ScopedAllowIO::ScopedAllowIO()
: was_allowed_(SetIOAllowed(true)) {}
ThreadRestrictions::ScopedAllowIO::~ScopedAllowIO() {
SetIOAllowed(was_allowed_);
}
// static
bool ThreadRestrictions::SetIOAllowed(bool allowed) {
bool previous_disallowed = g_blocking_disallowed.Get().Get();
g_blocking_disallowed.Get().Set(!allowed);
return !previous_disallowed;
}
// static
bool ThreadRestrictions::SetSingletonAllowed(bool allowed) {
bool previous_disallowed = g_singleton_disallowed.Get().Get();
g_singleton_disallowed.Get().Set(!allowed);
return !previous_disallowed;
}
// static
void ThreadRestrictions::AssertSingletonAllowed() {
if (g_singleton_disallowed.Get().Get()) {
NOTREACHED() << "LazyInstance/Singleton is not allowed to be used on this "
<< "thread. Most likely it's because this thread is not "
<< "joinable (or the current task is running with "
<< "TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN semantics), so "
<< "AtExitManager may have deleted the object on shutdown, "
<< "leading to a potential shutdown crash. If you need to use "
<< "the object from this context, it'll have to be updated to "
<< "use Leaky traits.";
}
}
// static
void ThreadRestrictions::DisallowWaiting() {
DisallowBaseSyncPrimitives();
}
bool ThreadRestrictions::SetWaitAllowed(bool allowed) {
bool previous_disallowed = g_base_sync_primitives_disallowed.Get().Get();
g_base_sync_primitives_disallowed.Get().Set(!allowed);
return !previous_disallowed;
}
ThreadRestrictions::ScopedAllowWait::ScopedAllowWait()
: was_allowed_(SetWaitAllowed(true)) {}
ThreadRestrictions::ScopedAllowWait::~ScopedAllowWait() {
SetWaitAllowed(was_allowed_);
}
} // namespace base
#endif // DCHECK_IS_ON()
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