Correct native API documentation related to MediaDrm offline use case

These doc updates were made previously to the java API but some
did not make it into the native API.

Change-Id: I9b7bfcd77bc593685254baca1c148deb7e1f91c7
related-to-bug: 8621588

1 files changed, 33 insertions, 11 deletions

diff --git a/include/media/drm/DrmAPI.h b/include/media/drm/DrmAPI.h
index c89f2d6a76..fbf93bc994 100644
--- a/include/media/drm/DrmAPI.h
+++ b/include/media/drm/DrmAPI.h
@@ -80,10 +80,12 @@ namespace android {
 
         // Drm keys can be for offline content or for online streaming.
         // Offline keys are persisted on the device and may be used when the device
-        // is disconnected from the network.
+        // is disconnected from the network.  The Release type is used to request
+        // that offline keys be no longer restricted to offline use.
         enum KeyType {
             kKeyType_Offline,
-            kKeyType_Streaming
+            kKeyType_Streaming,
+            kKeyType_Release
         };
 
         DrmPlugin() {}
@@ -101,35 +103,55 @@ namespace android {
         // is used to obtain an opaque key request blob that is delivered to the
         // license server.
         //
+        // The scope parameter may be a sessionId or a keySetId, depending on the
+        // specified keyType.  When the keyType is kKeyType_Offline or
+        // kKeyType_Streaming, scope should be set to the sessionId the keys will be
+        // provided to.  When the keyType is kKeyType_Release, scope should be set to
+        // the keySetId of the keys being released.  Releasing keys from a device
+        // invalidates them for all sessions.
+        //
         // The init data passed to getKeyRequest is container-specific and its
         // meaning is interpreted based on the mime type provided in the mimeType
         // parameter to getKeyRequest.  It could contain, for example, the content
         // ID, key ID or other data obtained from the content metadata that is required
-        // in generating the key request.
+        // in generating the key request.  Init may be null when keyType is
+        // kKeyType_Release.
+        //
+        // mimeType identifies the mime type of the content
         //
-        // keyType specifes if the keys are to be used for streaming or offline content
+        // keyType specifies if the keys are to be used for streaming or offline content
         //
         // optionalParameters are included in the key request message to allow a
         // client application to provide additional message parameters to the server.
         //
         // If successful, the opaque key request blob is returned to the caller.
         virtual status_t
-            getKeyRequest(Vector<uint8_t> const &sessionId,
+            getKeyRequest(Vector<uint8_t> const &scope,
                           Vector<uint8_t> const &initData,
                           String8 const &mimeType, KeyType keyType,
                           KeyedVector<String8, String8> const &optionalParameters,
                           Vector<uint8_t> &request, String8 &defaultUrl) = 0;
 
+        //
         // After a key response is received by the app, it is provided to the
-        // Drm plugin using provideKeyResponse.  Returns the id of the key set
-        // in keySetId.  The keySetId can be used by removeKeys or restoreKeys
-        // when the keys are used for offline content.
-        virtual status_t provideKeyResponse(Vector<uint8_t> const &sessionId,
+        // Drm plugin using provideKeyResponse.
+        //
+        // scope may be a sessionId or a keySetId depending on the type of the
+        // response.  Scope should be set to the sessionId when the response is
+        // for either streaming or offline key requests.  Scope should be set to the
+        // keySetId when the response is for a release request.
+        //
+        // When the response is for an offline key request, a keySetId is returned
+        // in the keySetId vector parameter that can be used to later restore the
+        // keys to a new session with the method restoreKeys. When the response is
+        // for a streaming or release request, no keySetId is returned.
+        //
+        virtual status_t provideKeyResponse(Vector<uint8_t> const &scope,
                                             Vector<uint8_t> const &response,
                                             Vector<uint8_t> &keySetId) = 0;
 
-        // Remove the persisted keys associated with an offline license for a session.
-        virtual status_t removeKeys(Vector<uint8_t> const &keySetId) = 0;
+        // Remove the current keys from a session
+        virtual status_t removeKeys(Vector<uint8_t> const &sessionId) = 0;
 
         // Restore persisted offline keys into a new session.  keySetId identifies
         // the keys to load, obtained from a prior call to provideKeyResponse().