Bug 1057171 - Implement MediaKeySession.getUsableKeyIds. r=bz

content/media/eme/CDMCaps.cpp

@@ -184,4 +184,16 @@ CDMCaps::AutoLock::CanDecryptVideo()
   return mData.HasCap(GMP_EME_CAP_DECRYPT_VIDEO);
 }
 
+void
+CDMCaps::AutoLock::GetUsableKeysForSession(const nsAString& aSessionId,
+                                           nsTArray<CencKeyId>& aOutKeyIds)
+{
+  for (size_t i = 0; i < mData.mUsableKeyIds.Length(); i++) {
+    const auto& key = mData.mUsableKeyIds[i];
+    if (key.mSessionId.Equals(aSessionId)) {
+      aOutKeyIds.AppendElement(key.mId);
+    }
+  }
+}
+
 } // namespace mozilla

content/media/eme/CDMCaps.h

@@ -42,6 +42,8 @@ public:
     void SetKeyUnusable(const CencKeyId& aKeyId, const nsString& aSessionId);
 
     void DropKeysForSession(const nsAString& aSessionId);
+    void GetUsableKeysForSession(const nsAString& aSessionId,
+                                 nsTArray<CencKeyId>& aOutKeyIds);
 
     // Sets the capabilities of the CDM. aCaps is the logical OR of the
     // GMP_EME_CAP_* flags from gmp-decryption.h.

content/media/eme/MediaKeySession.cpp

@@ -171,6 +171,34 @@ MediaKeySession::Remove(ErrorResult& aRv)
   return promise.forget();
 }
 
+already_AddRefed<Promise>
+MediaKeySession::GetUsableKeyIds(ErrorResult& aRv)
+{
+  nsRefPtr<Promise> promise(mKeys->MakePromise(aRv));
+  if (aRv.Failed()) {
+    return nullptr;
+  }
+
+  if (IsClosed() || !mKeys->GetCDMProxy()) {
+    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return promise.forget();
+  }
+
+  nsTArray<CencKeyId> keyIds;
+  {
+    CDMCaps::AutoLock caps(mKeys->GetCDMProxy()->Capabilites());
+    caps.GetUsableKeysForSession(mSessionId, keyIds);
+  }
+
+  nsTArray<TypedArrayCreator<ArrayBuffer>> array;
+  for (size_t i = 0; i < keyIds.Length(); i++) {
+    array.AppendElement(keyIds[i]);
+  }
+  promise->MaybeResolve(array);
+
+  return promise.forget();
+}
+
 void
 MediaKeySession::DispatchKeyMessage(const nsTArray<uint8_t>& aMessage,
                                     const nsAString& aURL)

content/media/eme/MediaKeySession.h

@@ -70,6 +70,8 @@ public:
 
   already_AddRefed<Promise> Remove(ErrorResult& aRv);
 
+  already_AddRefed<Promise> GetUsableKeyIds(ErrorResult& aRv);
+
   void DispatchKeyMessage(const nsTArray<uint8_t>& aMessage,
                           const nsAString& aURL);
 

dom/webidl/MediaKeySession.webidl

@@ -19,10 +19,6 @@ interface MediaKeySession : EventTarget {
   readonly attribute DOMString keySystem;
   readonly attribute DOMString sessionId;
 
-  // Invalid WebIDL, doesn't work.
-  // https://www.w3.org/Bugs/Public/show_bug.cgi?id=25594
-  // readonly attribute Array<Uint8Array> usableKeyIds;
-
   readonly attribute unrestricted double expiration;
 
   // void, not any: https://www.w3.org/Bugs/Public/show_bug.cgi?id=26457
@@ -40,4 +36,7 @@ interface MediaKeySession : EventTarget {
   // void, not any: https://www.w3.org/Bugs/Public/show_bug.cgi?id=26457
   [NewObject, Throws]
   Promise<void> remove();
+
+  [NewObject, Throws]
+  Promise<sequence<ArrayBuffer>> getUsableKeyIds();
 };