[Open Screen] Fix two unitialized reads dicovered by MSAN.

- Fix read of unitialized watch duration in OSP
- Fix uninitialized endpoint_id in OSP

Also, update Subscription to follow rule of 3/5, and simplify how
query IDs are allocated in the cast_app_discovery_service.

Bug: chromium:1143946
Change-Id: I78f3dd630626eaf47930d8a5c9bfdc3d05b49fb6
Reviewed-on: https://chromium-review.googlesource.com/c/openscreen/+/2511074
Commit-Queue: mark a. foltz <mfoltz@chromium.org>
Reviewed-by: Brandon Tolsch <btolsch@chromium.org>

2 files changed, 12 insertions, 17 deletions

diff --git a/cast/sender/public/cast_app_discovery_service.cc b/cast/sender/public/cast_app_discovery_service.cc
index c561b386..8299aff4 100644
--- a/cast/sender/public/cast_app_discovery_service.cc
+++ b/cast/sender/public/cast_app_discovery_service.cc
@@ -17,14 +17,16 @@ CastAppDiscoveryService::Subscription::Subscription(Subscription&& other)
   other.discovery_service_ = nullptr;
 }
 
-CastAppDiscoveryService::Subscription::~Subscription() {
-  Reset();
+CastAppDiscoveryService::Subscription&
+CastAppDiscoveryService::Subscription::operator=(Subscription&& other) {
+  id_ = other.id_;
+  discovery_service_ = other.discovery_service_;
+  other.discovery_service_ = nullptr;
+  return *this;
 }
 
-CastAppDiscoveryService::Subscription& CastAppDiscoveryService::Subscription::
-operator=(Subscription other) {
-  Swap(other);
-  return *this;
+CastAppDiscoveryService::Subscription::~Subscription() {
+  Reset();
 }
 
 void CastAppDiscoveryService::Subscription::Reset() {
diff --git a/cast/sender/public/cast_app_discovery_service.h b/cast/sender/public/cast_app_discovery_service.h
index ccb586ff..6ce5ee78 100644
--- a/cast/sender/public/cast_app_discovery_service.h
+++ b/cast/sender/public/cast_app_discovery_service.h
@@ -23,17 +23,18 @@ class CastAppDiscoveryService {
 
   class Subscription {
    public:
+    Subscription(CastAppDiscoveryService* discovery_service, uint32_t id);
     Subscription(Subscription&&);
+    Subscription(Subscription&) = delete;
+    Subscription& operator=(Subscription&&);
+    Subscription& operator=(const Subscription&) = delete;
     ~Subscription();
-    Subscription& operator=(Subscription);
 
     void Reset();
 
    private:
     friend class CastAppDiscoveryService;
 
-    Subscription(CastAppDiscoveryService* discovery_service, uint32_t id);
-
     void Swap(Subscription& other);
 
     CastAppDiscoveryService* discovery_service_;
@@ -57,15 +58,7 @@ class CastAppDiscoveryService {
   // this method when the user initiates a user gesture.
   virtual void Refresh() = 0;
 
- protected:
-  Subscription MakeSubscription(CastAppDiscoveryService* discovery_service,
-                                uint32_t id) {
-    return Subscription(discovery_service, id);
-  }
-
  private:
-  friend class Subscription;
-
   virtual void RemoveAvailabilityCallback(uint32_t id) = 0;
 };