Widevine MediaCas client code that works with Android R

plugin/include/widevine_cas_session.h

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+// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine Master
+// License Agreement.
+
+#ifndef WIDEVINE_CAS_SESSION_H
+#define WIDEVINE_CAS_SESSION_H
+
+#include <memory>
+#include <mutex>
+#include <string>
+
+#include "cas_types.h"
+#include "crypto_session.h"
+#include "ecm_parser.h"
+
+namespace wvcas {
+
+class WidevineCasSession;
+typedef std::shared_ptr<WidevineCasSession> CasSessionPtr;
+
+class CasKeySlotData {
+ public:
+  CasKeySlotData() {}
+  ~CasKeySlotData() {}
+
+  KeySlot& operator[](KeySlotId slot_id);
+  const KeySlot& operator[](KeySlotId slot_id) const;
+
+ private:
+  KeySlot keys_[2];  // Odd and even key slots.
+};
+
+enum class ScramblingControl {
+  kScrambling_Unscrambled = 0,
+  kScrambling_Reserved = 1,
+  kScrambling_EvenKey = 2,
+  kScrambling_OddKey = 3,
+};
+
+// WidevineCasSession represents an encryption context for a single ECM key
+// stream. It processes ECMs for the stream and maintains the key information.
+class WidevineCasSession {
+ public:
+  WidevineCasSession() {}
+  virtual ~WidevineCasSession();
+
+  CasStatus initialize(std::shared_ptr<CryptoSession> crypto_session,
+                       uint32_t* session_id);
+
+  // Get the current key information. This method will be used by a descrambler
+  // plugin to obtain the current key information.
+  const KeySlot& key(KeySlotId slot_id) const;
+
+  // Process an ecm and extract the key slot data. Extracted data will be used
+  // to update |current_ecm_| and |entitlement_key_id_| and |keys_|.
+  // |parental_control_age| (if non-zero) must be greater or equal to the
+  // age_restriction field specified in |ecm|. Otherwise, ECM will not be
+  // processed and error will be returned.
+  virtual CasStatus processEcm(const CasEcm& ecm, uint8_t parental_control_age);
+
+  // Returns the security level retrieved from OEMCrypto.
+  const char* securityLevel();
+
+  // Returns current ecm age restriction value.
+  uint8_t GetEcmAgeRestriction() { return ecm_age_restriction_; }
+
+  WidevineCasSession(const WidevineCasSession&) = delete;
+  WidevineCasSession& operator=(const WidevineCasSession&) = delete;
+
+ private:
+  // Creates an EcmParser.
+  virtual std::unique_ptr<const EcmParser> getEcmParser(
+      const CasEcm& ecm) const;
+
+  CasKeySlotData keys_;  // Odd and even key slots.
+  std::string entitlement_key_id_;
+  std::mutex lock_;
+  CasEcm current_ecm_;
+  uint8_t ecm_age_restriction_ = 0;
+  std::shared_ptr<CryptoSession> crypto_session_;
+  // Id of the entitled key session in OEMCrypto associated with this session.
+  uint32_t key_session_id_;
+};
+
+}  // namespace wvcas
+
+#endif  // WIDEVINE_CAS_SESSION_H