Bug: Uninitialized pointer `ReadWriteLocker::lock_` causes UB on error paths

[grisutheguru]

Summary

The ReadWriteLocker class in src/video/videoframe.h has an uninitialized pointer member that causes undefined behavior when default-constructed instances are destroyed.

Details

// videoframe.h
class ReadWriteLocker {
public:
    ReadWriteLocker() = default;  // lock_ is NOT initialized
    // ...
    ~ReadWriteLocker()
    {
        if (lock_ != nullptr) {   // reads uninitialized memory!
            lock_->unlock();
        }
    }
private:
    QReadWriteLock* lock_;        // no default initializer
};

Default-constructed ReadWriteLocker instances are returned on error paths in toGenericObject() (line 708) and toToxYUVFrame() (line 320). When these are destroyed, the destructor reads the uninitialized lock_ pointer and may call unlock() on a garbage address.

Suggested Fix

private:
    QReadWriteLock* lock_ = nullptr;

One-character fix, eliminates an entire class of UB.

Impact

Potential crash on any video frame conversion error path. Would be caught by ASan/MSan.