Implemented this for DOM camera support: class RwAutoLockRead { public: RwAutoLockRead(PRRWLock* aRwLock) : mRwLock(aRwLock) { PR_RWLock_Rlock(mRwLock); } ~RwAutoLockRead() { PR_RWLock_Unlock(mRwLock); } protected: PRRWLock *mRwLock; }; class RwAutoLockWrite { public: RwAutoLockWrite(PRRWLock* aRwLock) : mRwLock(aRwLock) { PR_RWLock_Wlock(mRwLock); } ~RwAutoLockWrite() { PR_RWLock_Unlock(mRwLock); } protected: PRRWLock *mRwLock; }; May be useful to others, should migrate to a more useful location once DOM camera supports lands.

(In reply to Mike Habicher [:mikeh] from comment #0) > May be useful to others, should migrate to a more useful location once DOM > camera supports lands. *support.

What use does that have, when you have a separate class for read and write lock? Anyways, this should be implemented on top of bug 773491

(In reply to Mike Hommey [:glandium] from comment #2) > What use does that have, when you have a separate class for read and write lock? They both operate on the same lock (created elsewhere), but give the lock the usual C++ scope management.