blob: b01e04a8d1a58558d199c4f0ad4ab7041c30c395 [file] [log] [blame]
// Copyright 2016 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 "mojo/public/cpp/bindings/sync_call_restrictions.h"
#if ENABLE_SYNC_CALL_RESTRICTIONS
#include "base/debug/leak_annotations.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/threading/thread_local.h"
#include "mojo/public/c/system/core.h"
namespace mojo {
namespace {
class SyncCallSettings {
public:
static SyncCallSettings* current();
bool allowed() const {
return scoped_allow_count_ > 0 || system_defined_value_;
}
void IncreaseScopedAllowCount() { scoped_allow_count_++; }
void DecreaseScopedAllowCount() {
DCHECK_LT(0u, scoped_allow_count_);
scoped_allow_count_--;
}
private:
SyncCallSettings();
~SyncCallSettings();
bool system_defined_value_ = true;
size_t scoped_allow_count_ = 0;
};
base::LazyInstance<base::ThreadLocalPointer<SyncCallSettings>>::Leaky
g_sync_call_settings = LAZY_INSTANCE_INITIALIZER;
// static
SyncCallSettings* SyncCallSettings::current() {
SyncCallSettings* result = g_sync_call_settings.Pointer()->Get();
if (!result) {
result = new SyncCallSettings();
ANNOTATE_LEAKING_OBJECT_PTR(result);
DCHECK_EQ(result, g_sync_call_settings.Pointer()->Get());
}
return result;
}
SyncCallSettings::SyncCallSettings() {
MojoResult result = MojoGetProperty(MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED,
&system_defined_value_);
DCHECK_EQ(MOJO_RESULT_OK, result);
DCHECK(!g_sync_call_settings.Pointer()->Get());
g_sync_call_settings.Pointer()->Set(this);
}
SyncCallSettings::~SyncCallSettings() {
g_sync_call_settings.Pointer()->Set(nullptr);
}
} // namespace
// static
void SyncCallRestrictions::AssertSyncCallAllowed() {
if (!SyncCallSettings::current()->allowed()) {
LOG(FATAL) << "Mojo sync calls are not allowed in this process because "
<< "they can lead to jank and deadlock. If you must make an "
<< "exception, please see "
<< "SyncCallRestrictions::ScopedAllowSyncCall and consult "
<< "mojo/OWNERS.";
}
}
// static
void SyncCallRestrictions::IncreaseScopedAllowCount() {
SyncCallSettings::current()->IncreaseScopedAllowCount();
}
// static
void SyncCallRestrictions::DecreaseScopedAllowCount() {
SyncCallSettings::current()->DecreaseScopedAllowCount();
}
} // namespace mojo
#endif // ENABLE_SYNC_CALL_RESTRICTIONS