media/mojo/interfaces/content_decryption_module.mojom

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module media.interfaces;

import "media/mojo/interfaces/decryptor.mojom";

// Transport layer of media::MediaKeys::Exception (see media/base/media_keys.h).
// This is used for ContentDecryptionModule (CDM) promise rejections.
enum CdmException {
  NOT_SUPPORTED_ERROR,
  INVALID_STATE_ERROR,
  INVALID_ACCESS_ERROR,
  QUOTA_EXCEEDED_ERROR,
  UNKNOWN_ERROR,
  CLIENT_ERROR,
  OUTPUT_ERROR
};

// Transport layer of media::CdmKeyInformation::KeyStatus (see
// media/base/cdm_key_information.h). This is used for indicating the status
// of a specific key ID.
enum CdmKeyStatus {
  USABLE,
  INTERNAL_ERROR,
  EXPIRED,
  OUTPUT_RESTRICTED,
  OUTPUT_DOWNSCALED,
  KEY_STATUS_PENDING
};

// Transport layer of media::CdmConfig (see media/base/cdm_config.h).
struct CdmConfig {
  bool allow_distinctive_identifier;
  bool allow_persistent_state;
  bool use_hw_secure_codecs;
};

// Transport layer of media::CdmPromise (see media/base/cdm_promise.h).
// - When |success| is true, the promise is resolved and all other fields should
//   be ignored.
// - When |success| is false, the promise is rejected with |exception|,
//   |system_code| and |error_message|.
struct CdmPromiseResult {
  bool success;
  CdmException exception;
  uint32 system_code;
  string? error_message;
};

// Transport layer of media::CdmKeyInformation (see
// media/base/cdm_key_information.h). It is used to specify a key_id and it's
// associated status.
struct CdmKeyInformation {
  array<uint8> key_id;
  CdmKeyStatus status;
  uint32 system_code;
};

// See media::MediaKeys::MessageType
enum CdmMessageType {
  LICENSE_REQUEST,
  LICENSE_RENEWAL,
  LICENSE_RELEASE
};

// An interface that represents a CDM in the Encrypted Media Extensions (EME)
// spec (https://w3c.github.io/encrypted-media/). See media/base/media_keys.h.
interface ContentDecryptionModule {
  // See media::MediaKeys::SessionType.
  enum SessionType {
    TEMPORARY_SESSION,
    PERSISTENT_LICENSE_SESSION,
    PERSISTENT_RELEASE_MESSAGE_SESSION
  };

  // See media::EmeInitDataType.
  enum InitDataType {
    UNKNOWN,
    WEBM,
    CENC,
    KEYIDS
  };

  // Sets ContentDecryptionModuleClient. Must be called before any other calls.
  SetClient(ContentDecryptionModuleClient client);

  // Initializes the CDM. If initialization failed (e.g. |key_system| or
  // |cdm_config| is not supported), |result.success| will be false and |cdm_id|
  // will be zero. Upon success, |cdm_id| will be non-zero and will later be
  // used to locate the CDM at the remote side. |decryptor| is the remote
  // Decryptor.
  Initialize(string key_system, string security_origin, CdmConfig cdm_config)
      => (CdmPromiseResult result, int32 cdm_id, Decryptor? decryptor);

  // Provides a server certificate to be used to encrypt messages to the
  // license server.
  SetServerCertificate(array<uint8> certificate_data)
      => (CdmPromiseResult result);

  // Creates a session with the |init_data_type|, |init_data| and |session_type|
  // provided. If |result.success| is false, the output |session_id| will be
  // null.
  CreateSessionAndGenerateRequest(SessionType session_type,
                                  InitDataType init_data_type,
                                  array<uint8> init_data)
      => (CdmPromiseResult result, string? session_id);

  // Loads the session associated with |session_id| and |session_type|.
  // Combinations of |result.success| and |session_id| means:
  //   (true, non-null) : Session successfully loaded.
  //   (true, null) : Session not found.
  //   (false, non-null): N/A; this combination is not allowed.
  //   (false, null) : Unexpected error. See other fields in |result|.
  LoadSession(SessionType session_type, string session_id)
      => (CdmPromiseResult result, string? session_id);

  // Updates a session specified by |session_id| with |response|.
  UpdateSession(string session_id, array<uint8> response)
      => (CdmPromiseResult result);

  // Closes the session specified by |session_id|.
  CloseSession(string session_id) => (CdmPromiseResult result);

  // Removes stored session data associated with the active session specified by
  // |session_id|.
  RemoveSession(string session_id) => (CdmPromiseResult result);
};

// Session callbacks. See media/base/media_keys.h for details.
interface ContentDecryptionModuleClient {
  OnSessionMessage(string session_id, CdmMessageType message_type,
                   array<uint8> message, string legacy_destination_url);

  OnSessionClosed(string session_id);

  OnLegacySessionError(string session_id, CdmException exception,
                       uint32 system_code, string error_message);

  OnSessionKeysChange(string session_id, bool has_additional_usable_key,
                      array<CdmKeyInformation> key_information);

  // Provide session expiration update for |session_id|.
  // |new_expiry_time_sec| is the number of seconds since epoch (Jan 1, 1970).
  OnSessionExpirationUpdate(string session_id, double new_expiry_time_sec);
};