Convenience method to check cam / mic permissions (#231)

* impl

* optimize

* clean

* Update LiveKit+DeviceHelpers.swift

Sources/LiveKit/LiveKit+DeviceHelpers.swift

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2023 LiveKit
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import AVFoundation
+
+extension LiveKit {
+
+    /// Helper method to ensure authorization for video(camera) / audio(microphone) permissions in a single call.
+    public static func ensureDeviceAccess(for types: Set<AVMediaType>) async -> Bool {
+
+        assert(!types.isEmpty, "Please specify at least 1 type")
+
+        for type in types {
+
+            assert([.video, .audio].contains(type), "types must be .video or .audio")
+
+            let status = AVCaptureDevice.authorizationStatus(for: type)
+            switch status {
+            case .notDetermined:
+                if !(await AVCaptureDevice.requestAccess(for: type)) {
+                    return false
+                }
+            case .restricted, .denied: return false
+            case .authorized: continue // No action needed for authorized status.
+            @unknown default:
+                logger.error("Unknown AVAuthorizationStatus")
+                return false
+            }
+        }
+
+        return true
+    }
+}