Implement Method to Release Licenses Without a Server Roundtrip

Merge from Widevine repo of http://go/wvgerrit/52480

Partners have asked for a way to release offline licenses without
using a release message. This is typically used by cable partners who
are caching licenses ahead of time and do not care about usage
statistics.

As part of implementing this request, CdmSession::DeleteLicense() was
renamed to reflect that it only deletes the *files* associated with a
license, and a new CdmSession::DeleteLicense() has been written that
also cleans up other related data.

Bug: 77955334
Test: CE CDM Unit Tests
Test: tested as part of http://go/ag/4674759
Change-Id: I00d6e20935c5fecb3ac9be6757c0f191d85c6bd6

libwvdrmengine/cdm/core/include/cdm_engine.h

@@ -113,8 +113,18 @@ class CdmEngine {
   virtual CdmResponseType RestoreKey(const CdmSessionId& session_id,
                                      const CdmKeySetId& key_set_id);
 
+  // This method releases the crypto resources and policy resources associated
+  // with the given session. This renders the session largely useless. It is
+  // preferable to close the session outright. This method does not delete any
+  // stored offline data associated with the session.
   virtual CdmResponseType RemoveKeys(const CdmSessionId& session_id);
 
+  // This method removes all offline data associated with the session, such as
+  // offline keys and usage info. It should be used with care, as it deletes the
+  // info immediately and without using a release message, so the server is not
+  // able to receive usage info or track releases for offline licenses.
+  virtual CdmResponseType RemoveLicense(const CdmSessionId& session_id);
+
   // Construct valid renewal request for the current session keys.
   virtual CdmResponseType GenerateRenewalRequest(
       const CdmSessionId& session_id, CdmKeyRequest* key_request);

libwvdrmengine/cdm/core/include/cdm_session.h

@@ -153,8 +153,13 @@ class CdmSession {
   // preferable to simply delete this object rather than call this method.
   virtual CdmResponseType RemoveKeys();
 
-  // Delete current license and matching usage record
-  bool DeleteLicense();
+  // Remove the current offline license and/or matching usage record, if any
+  // exist.
+  CdmResponseType RemoveLicense();
+  // Delete this session's associated license or usage record file. Note that,
+  // unlike RemoveLicense(), this method ONLY affects the file system and does
+  // not touch the usage table headers.
+  bool DeleteLicenseFile();
 
   // Generate unique ID for each new session.
   CdmSessionId GenerateSessionId();

libwvdrmengine/cdm/core/include/wv_cdm_types.h

@@ -334,6 +334,7 @@ enum CdmResponseType {
   SESSION_NOT_FOUND_17 = 290,
   SESSION_NOT_FOUND_18 = 291,
   DEVICE_CANNOT_REPROVISION = 293,
+  SESSION_NOT_FOUND_19 = 294,
 };
 
 enum CdmKeyStatus {

libwvdrmengine/cdm/core/src/cdm_engine.cpp

@@ -414,6 +414,18 @@ CdmResponseType CdmEngine::RemoveKeys(const CdmSessionId& session_id) {
   return NO_ERROR;
 }
 
+CdmResponseType CdmEngine::RemoveLicense(const CdmSessionId& session_id) {
+  LOGI("CdmEngine::RemoveLicense");
+
+  shared_ptr<CdmSession> session;
+  if (!session_map_.FindSession(session_id, &session)) {
+    LOGE("session_id not found = %s", session_id.c_str());
+    return SESSION_NOT_FOUND_19;
+  }
+
+  return session->RemoveLicense();
+}
+
 CdmResponseType CdmEngine::GenerateRenewalRequest(
     const CdmSessionId& session_id, CdmKeyRequest* key_request) {
   LOGI("CdmEngine::GenerateRenewalRequest");
@@ -1167,8 +1179,8 @@ CdmResponseType CdmEngine::GetUsageInfo(const std::string& app_id,
   switch (status) {
     case KEY_MESSAGE:
       break;
-    case KEY_CANCELED:                  // usage information not present in
-      usage_session_->DeleteLicense();  // OEMCrypto, delete and try again
+    case KEY_CANCELED:                      // usage information not present in
+      usage_session_->DeleteLicenseFile();  // OEMCrypto, delete and try again
       usage_info->clear();
       break;
     default:
@@ -1455,7 +1467,7 @@ CdmResponseType CdmEngine::LoadUsageSession(const CdmKeySetId& key_set_id,
       break;
     case KEY_CANCELED:
       // usage information not present in OEMCrypto, delete and try again
-      session->DeleteLicense();
+      session->DeleteLicenseFile();
       break;
     default:
       LOGE("CdmEngine::LoadUsageSession: generate release request error: %d",

libwvdrmengine/cdm/core/src/cdm_session.cpp

@@ -715,16 +715,7 @@ CdmResponseType CdmSession::ReleaseKey(const CdmKeyResponse& key_response) {
 
   if (sts != KEY_ADDED) return (sts == KEY_ERROR) ? RELEASE_KEY_ERROR : sts;
 
-  if (is_offline_ || has_provider_session_token()) {
-    DeleteLicense();
-
-    if (usage_support_type_ == kUsageEntrySupport &&
-        has_provider_session_token()) {
-      sts = DeleteUsageEntry(usage_entry_number_);
-      if (NO_ERROR != sts) return sts;
-    }
-  }
-  return NO_ERROR;
+  return RemoveLicense();
 }
 
 CdmResponseType CdmSession::DeleteUsageEntry(uint32_t usage_entry_number) {
@@ -897,9 +888,21 @@ CdmResponseType CdmSession::RemoveKeys() {
   return NO_ERROR;
 }
 
-bool CdmSession::DeleteLicense() {
-  if (!is_offline_ && !has_provider_session_token())
-    return false;
+CdmResponseType CdmSession::RemoveLicense() {
+  if (is_offline_ || has_provider_session_token()) {
+    DeleteLicenseFile();
+
+    if (usage_support_type_ == kUsageEntrySupport &&
+        has_provider_session_token()) {
+      CdmResponseType sts = DeleteUsageEntry(usage_entry_number_);
+      if (NO_ERROR != sts) return sts;
+    }
+  }
+  return NO_ERROR;
+}
+
+bool CdmSession::DeleteLicenseFile() {
+  if (!is_offline_ && !has_provider_session_token()) return false;
 
   if (is_offline_) {
     return file_handle_->DeleteLicense(key_set_id_);

libwvdrmengine/cdm/core/test/test_printers.cpp

@@ -601,6 +601,8 @@ void PrintTo(const enum CdmResponseType& value, ::std::ostream* os) {
       break;
     case DEVICE_CANNOT_REPROVISION: *os << "DEVICE_CANNOT_REPROVISION";
       break;
+    case SESSION_NOT_FOUND_19: *os << "SESSION_NOT_FOUND_19";
+      break;
     default:
       *os                                        << "Unknown CdmResponseType";
       break;

libwvdrmengine/include/mapErrors-inl.h

@@ -230,6 +230,7 @@ static android::status_t mapCdmResponseType(wvcdm::CdmResponseType res) {
     case wvcdm::SESSION_NOT_FOUND_10:
     case wvcdm::SESSION_NOT_FOUND_17:
     case wvcdm::SESSION_NOT_FOUND_18:
+    case wvcdm::SESSION_NOT_FOUND_19:
         return android::ERROR_DRM_SESSION_NOT_OPENED;
     case wvcdm::SESSION_KEYS_NOT_FOUND:
       return kSessionKeysNotFound;

libwvdrmengine/include_hidl/mapErrors-inl.h

@@ -58,6 +58,7 @@ static Status mapCdmResponseType(wvcdm::CdmResponseType res) {
     case wvcdm::SESSION_NOT_FOUND_10:
     case wvcdm::SESSION_NOT_FOUND_17:
     case wvcdm::SESSION_NOT_FOUND_18:
+    case wvcdm::SESSION_NOT_FOUND_19:
       return Status::ERROR_DRM_SESSION_NOT_OPENED;
 
     case wvcdm::DECRYPT_ERROR: