Source code
Revision control
Copy as Markdown
Other Tools
/*
* Copyright 2026 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef MODULES_PORTAL_PORTAL_GUARD_H_
#define MODULES_PORTAL_PORTAL_GUARD_H_
#include <glib.h>
#include "api/ref_counted_base.h"
#include "rtc_base/synchronization/mutex.h"
namespace webrtc {
// Ref-counted guard for safe cross-thread portal access from GDBus callbacks.
// Callbacks lock the mutex and check the portal pointer before use.
// Stop() nulls the pointer under the same mutex, waiting for any in-flight
// callback to finish.
struct PortalGuard : public RefCountedNonVirtual<PortalGuard> {
Mutex mutex;
gpointer portal = nullptr;
gpointer AddRefAndGet() {
AddRef();
return this;
}
};
inline void portal_guard_release(gpointer data) {
static_cast<PortalGuard*>(data)->Release();
}
// RAII lock for PortalGuard. Use ScopedPortalLock for async callbacks
// (releases the callback's ref) or ScopedPortalSignalLock for signal
// callbacks (ref is owned by the subscription).
enum class RefOwnership {
kOwnedByCallback, // Async: callback owns the ref, release on unlock.
kOwnedBySubscription, // Signal: subscription owns the ref via
// GDestroyNotify.
};
class ScopedPortalLockBase {
public:
ScopedPortalLockBase(const ScopedPortalLockBase&) = delete;
ScopedPortalLockBase& operator=(const ScopedPortalLockBase&) = delete;
gpointer portal() const { return guard_->portal; }
protected:
ScopedPortalLockBase(gpointer user_data, RefOwnership ownership)
: guard_(static_cast<PortalGuard*>(user_data)), ownership_(ownership) {
guard_->mutex.Lock();
}
~ScopedPortalLockBase() {
guard_->mutex.Unlock();
if (ownership_ == RefOwnership::kOwnedByCallback)
guard_->Release();
}
private:
PortalGuard* guard_;
RefOwnership ownership_;
};
// For async callbacks. Releases the ref on destruction because async
// callbacks fire exactly once and own their ref.
class ScopedPortalLock : public ScopedPortalLockBase {
public:
explicit ScopedPortalLock(gpointer user_data)
: ScopedPortalLockBase(user_data, RefOwnership::kOwnedByCallback) {}
};
// For signal callbacks. Does not release the ref because the signal
// subscription owns it. The ref is released by portal_guard_release
// (GDestroyNotify) when the subscription is removed.
class ScopedPortalSignalLock : public ScopedPortalLockBase {
public:
explicit ScopedPortalSignalLock(gpointer user_data)
: ScopedPortalLockBase(user_data, RefOwnership::kOwnedBySubscription) {}
};
} // namespace webrtc
#endif // MODULES_PORTAL_PORTAL_GUARD_H_