starboard/drm.h - cobalt - Git at Google

 // Copyright 2016 The Cobalt Authors. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // Module Overview: Starboard DRM module
 //
 // Provides definitions that allow for DRM support, which are common
 // between Player and Decoder interfaces.

 #ifndef STARBOARD_DRM_H_
 #define STARBOARD_DRM_H_

 #include "starboard/export.h"
 #include "starboard/types.h"

 #ifdef __cplusplus
 extern "C" {
 #endif

 // --- Types -----------------------------------------------------------------

 // The type of the session request.
 // https://www.w3.org/TR/encrypted-media/#idl-def-mediakeymessagetype
 typedef enum SbDrmSessionRequestType {
   kSbDrmSessionRequestTypeLicenseRequest,
   kSbDrmSessionRequestTypeLicenseRenewal,
   kSbDrmSessionRequestTypeLicenseRelease,
   kSbDrmSessionRequestTypeIndividualizationRequest,
 } SbDrmSessionRequestType;

 // The status of session related operations.
 // Used by |SbDrmSessionUpdateRequestFunc|, |SbDrmSessionUpdatedFunc|, and
 // |SbDrmServerCertificateUpdatedFunc| to indicate the status of the operation.
 // https://w3c.github.io/encrypted-media/#error-names
 typedef enum SbDrmStatus {
   kSbDrmStatusSuccess,
   kSbDrmStatusTypeError,
   kSbDrmStatusNotSupportedError,
   kSbDrmStatusInvalidStateError,
   kSbDrmStatusQuotaExceededError,
   // The following error can be used when the error status cannot be mapped to
   // one of the above errors.
   kSbDrmStatusUnknownError,
 } SbDrmStatus;

 // Status of a particular media key.
 // https://w3c.github.io/encrypted-media/#idl-def-MediaKeyStatus
 typedef enum SbDrmKeyStatus {
   kSbDrmKeyStatusUsable,
   kSbDrmKeyStatusExpired,
   kSbDrmKeyStatusReleased,
   kSbDrmKeyStatusRestricted,
   kSbDrmKeyStatusDownscaled,
   kSbDrmKeyStatusPending,
   kSbDrmKeyStatusError,
 } SbDrmKeyStatus;

 // A mapping of clear and encrypted bytes for a single subsample. All subsamples
 // within a sample must be encrypted with the same encryption parameters. The
 // clear bytes always appear first in the sample.
 typedef struct SbDrmSubSampleMapping {
   // How many bytes of the corresponding subsample are not encrypted
   int32_t clear_byte_count;

   // How many bytes of the corresponding subsample are encrypted.
   int32_t encrypted_byte_count;
 } SbDrmSubSampleMapping;

 typedef struct SbDrmKeyId {
   // The ID of the license (or key) required to decrypt this sample. For
   // PlayReady, this is the license GUID in packed little-endian binary form.
   uint8_t identifier[16];
   int identifier_size;
 } SbDrmKeyId;

 // Encryption scheme of the input sample, as defined in ISO/IEC 23001 part 7.
 typedef enum SbDrmEncryptionScheme {
   kSbDrmEncryptionSchemeAesCtr,
   kSbDrmEncryptionSchemeAesCbc,
 } SbDrmEncryptionScheme;

 // Encryption pattern of the input sample, as defined in ISO/IEC 23001 part 7.
 typedef struct SbDrmEncryptionPattern {
   uint32_t crypt_byte_block;
   uint32_t skip_byte_block;
 } SbDrmEncryptionPattern;

 // All the optional information needed per sample for encrypted samples.
 typedef struct SbDrmSampleInfo {
   // The encryption scheme of this sample.
   SbDrmEncryptionScheme encryption_scheme;

   // The encryption pattern of this sample.
   SbDrmEncryptionPattern encryption_pattern;

   // The Initialization Vector needed to decrypt this sample.
   uint8_t initialization_vector[16];
   int initialization_vector_size;

   // The ID of the license (or key) required to decrypt this sample. For
   // PlayReady, this is the license GUID in packed little-endian binary form.
   uint8_t identifier[16];
   int identifier_size;

   // The number of subsamples in this sample, must be at least 1.
   int32_t subsample_count;

   // The clear/encrypted mapping of each subsample in this sample. This must be
   // an array of |subsample_count| mappings.
   const SbDrmSubSampleMapping* subsample_mapping;
 } SbDrmSampleInfo;

 // A handle to a DRM system which can be used with either an SbDecoder or an
 // SbPlayer.
 typedef struct SbDrmSystemPrivate* SbDrmSystem;

 // A callback that will receive generated session update request when requested
 // from a SbDrmSystem. |drm_system| will be the DRM system that
 // SbDrmGenerateSessionUpdateRequest() was called on. |context| will be the same
 // context that was passed into the call to SbDrmCreateSystem().
 //
 // |status| is the status of the session request.
 //
 // |type| is the status of the session request.
 //
 // |error_message| may contain an optional error message when |status| isn't
 // |kSbDrmStatusSuccess| to provide more details about the error.  It may be
 // NULL if |status| is |kSbDrmStatusSuccess| or if no error message can be
 // provided.
 // |ticket| will be the same ticket that was passed to
 // SbDrmGenerateSessionUpdateRequest() or |kSbDrmTicketInvalid| if the update
 // request was generated by the DRM system.
 //
 // |session_id| cannot be NULL when |ticket| is |kSbDrmTicketInvalid|, even when
 // there was an error generating the request.  This allows Cobalt to find and
 // reject the correct Promise corresponding to the associated
 // SbDrmGenerateSessionUpdateRequest().
 typedef void (*SbDrmSessionUpdateRequestFunc)(SbDrmSystem drm_system,
                                               void* context,
                                               int ticket,
                                               SbDrmStatus status,
                                               SbDrmSessionRequestType type,
                                               const char* error_message,
                                               const void* session_id,
                                               int session_id_size,
                                               const void* content,
                                               int content_size,
                                               const char* url);

 // A callback for notifications that a session has been added, and subsequent
 // encrypted samples are actively ready to be decoded. |drm_system| will be the
 // DRM system that SbDrmUpdateSession() was called on. |context| will be the
 // same context passed into that call to SbDrmCreateSystem().
 //
 // |ticket| will be the same ticket that was passed to SbDrmUpdateSession().
 //
 // |status| is the status of the session request.
 //
 // |error_message| may contain an optional error message when |status| isn't
 // |kSbDrmStatusSuccess| to provide more details about the error.  It may be
 // NULL if |status| is |kSbDrmStatusSuccess| or if no error message can be
 // provided.
 // |succeeded| is whether the session was successfully updated or not.
 typedef void (*SbDrmSessionUpdatedFunc)(SbDrmSystem drm_system,
                                         void* context,
                                         int ticket,
                                         SbDrmStatus status,
                                         const char* error_message,
                                         const void* session_id,
                                         int session_id_size);

 // A callback for notifications that the status of one or more keys in a session
 // has been changed.  All keys of the session and their new status will be
 // passed along.  Any keys not in the list is considered as deleted.
 typedef void (*SbDrmSessionKeyStatusesChangedFunc)(
     SbDrmSystem drm_system,
     void* context,
     const void* session_id,
     int session_id_size,
     int number_of_keys,
     const SbDrmKeyId* key_ids,
     const SbDrmKeyStatus* key_statuses);

 // A callback for signalling that a session has been closed by the SbDrmSystem
 typedef void (*SbDrmSessionClosedFunc)(SbDrmSystem drm_system,
                                        void* context,
                                        const void* session_id,
                                        int session_id_size);

 // A callback to notify the caller of SbDrmUpdateServerCertificate() whether the
 // update has been successfully updated or not.
 typedef void (*SbDrmServerCertificateUpdatedFunc)(SbDrmSystem drm_system,
                                                   void* context,
                                                   int ticket,
                                                   SbDrmStatus status,
                                                   const char* error_message);

 // --- Constants -------------------------------------------------------------

 // An invalid SbDrmSystem.
 #define kSbDrmSystemInvalid ((SbDrmSystem)NULL)

 // A ticket for callback invocations initiated by the DRM system.
 #define kSbDrmTicketInvalid kSbInvalidInt

 // --- Functions -------------------------------------------------------------

 // Indicates whether |drm_system| is a valid SbDrmSystem.
 static SB_C_FORCE_INLINE bool SbDrmSystemIsValid(SbDrmSystem drm) {
   return drm != kSbDrmSystemInvalid;
 }

 // Indicates whether |ticket| is a valid ticket.
 static SB_C_FORCE_INLINE bool SbDrmTicketIsValid(int ticket) {
   return ticket != kSbDrmTicketInvalid;
 }

 // Creates a new DRM system that can be used when constructing an SbPlayer or an
 // SbDecoder.
 //
 // This function returns |kSbDrmSystemInvalid| if |key_system| is unsupported.
 //
 // Also see the documentation of SbDrmGenerateSessionUpdateRequest() and
 // SbDrmUpdateSession() for more details.
 //
 // |key_system|: The DRM key system to be created. The value should be in the
 // form of "com.example.somesystem" as suggested by
 // https://w3c.github.io/encrypted-media/#key-system. All letters in the value
 // should be lowercase and will be matched exactly with known DRM key systems of
 // the platform.
 // |context|: A value passed when any of this function's callback parameters are
 // called.
 // |update_request_callback|: A function that is called every time after
 // SbDrmGenerateSessionUpdateRequest() is called.
 // |session_updated_callback|: A function that is called every time after
 // SbDrmUpdateSession() is called.
 // |key_statuses_changed_callback|: A function that can be called to indicate
 // that key statuses have changed.
 // |server_certificate_updated_callback|: A function that is called to report
 // whether the server certificate has been successfully updated.  It is called
 // once and only once.  It is possible that the callback is called before the
 // function returns.
 // |session_closed_callback|: A function that can be called to indicate that a
 // session has closed.
 // If |NULL| is passed for any of the callbacks (|update_request_callback|,
 // |session_updated_callback|, |key_statuses_changed_callback|,
 // |server_certificate_updated_callback|, or |session_closed_callback|), then
 // |kSbDrmSystemInvalid| must be returned.

 SB_EXPORT SbDrmSystem SbDrmCreateSystem(
     const char* key_system,
     void* context,
     SbDrmSessionUpdateRequestFunc update_request_callback,
     SbDrmSessionUpdatedFunc session_updated_callback,
     SbDrmSessionKeyStatusesChangedFunc key_statuses_changed_callback,
     SbDrmServerCertificateUpdatedFunc server_certificate_updated_callback,
     SbDrmSessionClosedFunc session_closed_callback);

 // Asynchronously generates a session update request payload for
 // |initialization_data|, of |initialization_data_size|, in case sensitive
 // |type|, extracted from the media stream, in |drm_system|'s key system.
 //
 // This function calls |drm_system|'s |update_request_callback| function,
 // which is defined when the DRM system is created by SbDrmCreateSystem. When
 // calling that function, this function either sends |context| (also from
 // |SbDrmCreateSystem|) and a populated request, or it sends NULL |session_id|
 // if an error occurred.
 //
 // |drm_system|'s |context| may be used to route callbacks back to an object
 // instance.
 //
 // Callbacks may be called either from the current thread before this function
 // returns or from another thread.
 //
 // |drm_system|: The DRM system that defines the key system used for the session
 // update request payload as well as the callback function that is called as a
 // result of the function being called. Must not be |kSbDrmSystemInvalid|.
 //
 // |ticket|: The opaque ID that allows to distinguish callbacks from multiple
 // concurrent calls to SbDrmGenerateSessionUpdateRequest(), which will be passed
 // to |update_request_callback| as-is. It is the responsibility of the caller to
 // establish ticket uniqueness, issuing multiple requests with the same ticket
 // may result in undefined behavior. The value |kSbDrmTicketInvalid| must not be
 // used.
 //
 // |type|: The case-sensitive type of the session update request payload. Must
 //   not be NULL.
 // |initialization_data|: The data for which the session update
 //   request payload is created. Must not be NULL.
 // |initialization_data_size|: The size of the session update request payload.
 SB_EXPORT void SbDrmGenerateSessionUpdateRequest(
     SbDrmSystem drm_system,
     int ticket,
     const char* type,
     const void* initialization_data,
     int initialization_data_size);

 // Update session with |key|, in |drm_system|'s key system, from the license
 // server response. Calls |session_updated_callback| with |context| and whether
 // the update succeeded. |context| may be used to route callbacks back to an
 // object instance. The |key| must not be NULL.
 //
 // |drm_system| must not be |kSbDrmSystemInvalid|.
 // |ticket| is the opaque ID that allows to distinguish callbacks from multiple
 // concurrent calls to SbDrmUpdateSession(), which will be passed to
 // |session_updated_callback| as-is. It is the responsibility of the caller to
 // establish ticket uniqueness, issuing multiple calls with the same ticket may
 // result in undefined behavior.
 //
 // Once the session is successfully updated, an SbPlayer or SbDecoder associated
 // with that DRM key system will be able to decrypt encrypted samples.
 //
 // |drm_system|'s |session_updated_callback| may called either from the current
 // thread before this function returns or from another thread.
 // The |session_id| must not be NULL.
 SB_EXPORT void SbDrmUpdateSession(SbDrmSystem drm_system,
                                   int ticket,
                                   const void* key,
                                   int key_size,
                                   const void* session_id,
                                   int session_id_size);

 // Clear any internal states/resources related to the specified |session_id|.
 //
 // |drm_system| must not be |kSbDrmSystemInvalid|.
 // |session_id| must not be NULL.
 SB_EXPORT void SbDrmCloseSession(SbDrmSystem drm_system,
                                  const void* session_id,
                                  int session_id_size);

 // Returns true if server certificate of |drm_system| can be updated via
 // SbDrmUpdateServerCertificate().  The return value should remain the same
 // during the life time of |drm_system|.
 //
 // |drm_system|: The DRM system to check if its server certificate is updatable.
 // Must not be |kSbDrmSystemInvalid|.
 SB_EXPORT bool SbDrmIsServerCertificateUpdatable(SbDrmSystem drm_system);

 // Update the server certificate of |drm_system|.  The function can be called
 // multiple times.  It is possible that a call to it happens before the callback
 // of a previous call is called.
 // Note that this function should only be called after
 // |SbDrmIsServerCertificateUpdatable| is called first and returned true.
 //
 // |drm_system|: The DRM system whose server certificate is being updated. Must
 //   not be |kSbDrmSystemInvalid|.
 // |ticket|: The opaque ID that allows to distinguish callbacks from multiple
 //   concurrent calls to SbDrmUpdateServerCertificate(), which will be passed to
 //   |server_certificate_updated_callback| as-is. It is the responsibility of
 //   the caller to establish ticket uniqueness, issuing multiple requests with
 //   the same ticket may result in undefined behavior. The value
 //   |kSbDrmTicketInvalid| must not be used.
 // |certificate|: Pointer to the server certificate data. Must not be NULL.
 // |certificate_size|: Size of the server certificate data.
 SB_EXPORT void SbDrmUpdateServerCertificate(SbDrmSystem drm_system,
                                             int ticket,
                                             const void* certificate,
                                             int certificate_size);

 // Get the metrics of the underlying drm system.
 //
 // When it is called on an implementation that supports drm system metrics, it
 // should return a pointer containing the metrics as a blob, encoded using url
 // safe base64 without padding and line wrapping, with the size of the encoded
 // result in |size| on return. For example, on Android API level 28 or later, it
 // should return the result of MediaDrm.getPropertyByteArray("metrics"), encoded
 // using url safe base64 without padding and line wrapping. On systems using
 // Widevine CE CDM with oemcrypto 16 or later, it should return the metrics
 // retrieved via Cdm::getMetrics(), encoded using url safe base64 without
 // padding and line wrapping.  The returned pointer should remain valid and its
 // content should remain unmodified until the next time this function is called
 // on the associated |drm_system| or the |drm_system| is destroyed.
 //
 // When the metrics is empty on supported system, it should return a non-null
 // pointer with |size| set to 0.
 //
 // It should return NULL when there is no metrics support in the underlying drm
 // system, or when the drm system implementation fails to retrieve the metrics.
 //
 // |drm_system| must not be |kSbDrmSystemInvalid|.
 // |size| must not be NULL.
 SB_EXPORT const void* SbDrmGetMetrics(SbDrmSystem drm_system, int* size);

 // Destroys |drm_system|, which implicitly removes all keys installed in it and
 // invalidates all outstanding session update requests. A DRM system cannot be
 // destroyed unless any associated SbPlayer or SbDecoder has first been
 // destroyed.
 //
 // All callbacks are guaranteed to be finished when this function returns.  As a
 // result, if this function is called from a callback that is passed to
 // SbDrmCreateSystem(), a deadlock will occur.
 //
 // |drm_system|: The DRM system to be destroyed. Must not be
 //   |kSbDrmSystemInvalid|.
 SB_EXPORT void SbDrmDestroySystem(SbDrmSystem drm_system);

 #ifdef __cplusplus
 }  // extern "C"
 #endif

 #endif  // STARBOARD_DRM_H_
	// Copyright 2016 The Cobalt Authors. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// Module Overview: Starboard DRM module
	//
	// Provides definitions that allow for DRM support, which are common
	// between Player and Decoder interfaces.

	#ifndef STARBOARD_DRM_H_
	#define STARBOARD_DRM_H_

	#include "starboard/export.h"
	#include "starboard/types.h"

	#ifdef __cplusplus
	extern "C" {
	#endif

	// --- Types -----------------------------------------------------------------

	// The type of the session request.
	// https://www.w3.org/TR/encrypted-media/#idl-def-mediakeymessagetype
	typedef enum SbDrmSessionRequestType {
	kSbDrmSessionRequestTypeLicenseRequest,
	kSbDrmSessionRequestTypeLicenseRenewal,
	kSbDrmSessionRequestTypeLicenseRelease,
	kSbDrmSessionRequestTypeIndividualizationRequest,
	} SbDrmSessionRequestType;

	// The status of session related operations.
	// Used by \|SbDrmSessionUpdateRequestFunc\|, \|SbDrmSessionUpdatedFunc\|, and
	// \|SbDrmServerCertificateUpdatedFunc\| to indicate the status of the operation.
	// https://w3c.github.io/encrypted-media/#error-names
	typedef enum SbDrmStatus {
	kSbDrmStatusSuccess,
	kSbDrmStatusTypeError,
	kSbDrmStatusNotSupportedError,
	kSbDrmStatusInvalidStateError,
	kSbDrmStatusQuotaExceededError,
	// The following error can be used when the error status cannot be mapped to
	// one of the above errors.
	kSbDrmStatusUnknownError,
	} SbDrmStatus;

	// Status of a particular media key.
	// https://w3c.github.io/encrypted-media/#idl-def-MediaKeyStatus
	typedef enum SbDrmKeyStatus {
	kSbDrmKeyStatusUsable,
	kSbDrmKeyStatusExpired,
	kSbDrmKeyStatusReleased,
	kSbDrmKeyStatusRestricted,
	kSbDrmKeyStatusDownscaled,
	kSbDrmKeyStatusPending,
	kSbDrmKeyStatusError,
	} SbDrmKeyStatus;

	// A mapping of clear and encrypted bytes for a single subsample. All subsamples
	// within a sample must be encrypted with the same encryption parameters. The
	// clear bytes always appear first in the sample.
	typedef struct SbDrmSubSampleMapping {
	// How many bytes of the corresponding subsample are not encrypted
	int32_t clear_byte_count;

	// How many bytes of the corresponding subsample are encrypted.
	int32_t encrypted_byte_count;
	} SbDrmSubSampleMapping;

	typedef struct SbDrmKeyId {
	// The ID of the license (or key) required to decrypt this sample. For
	// PlayReady, this is the license GUID in packed little-endian binary form.
	uint8_t identifier[16];
	int identifier_size;
	} SbDrmKeyId;

	// Encryption scheme of the input sample, as defined in ISO/IEC 23001 part 7.
	typedef enum SbDrmEncryptionScheme {
	kSbDrmEncryptionSchemeAesCtr,
	kSbDrmEncryptionSchemeAesCbc,
	} SbDrmEncryptionScheme;

	// Encryption pattern of the input sample, as defined in ISO/IEC 23001 part 7.
	typedef struct SbDrmEncryptionPattern {
	uint32_t crypt_byte_block;
	uint32_t skip_byte_block;
	} SbDrmEncryptionPattern;

	// All the optional information needed per sample for encrypted samples.
	typedef struct SbDrmSampleInfo {
	// The encryption scheme of this sample.
	SbDrmEncryptionScheme encryption_scheme;

	// The encryption pattern of this sample.
	SbDrmEncryptionPattern encryption_pattern;

	// The Initialization Vector needed to decrypt this sample.
	uint8_t initialization_vector[16];
	int initialization_vector_size;

	// The ID of the license (or key) required to decrypt this sample. For
	// PlayReady, this is the license GUID in packed little-endian binary form.
	uint8_t identifier[16];
	int identifier_size;

	// The number of subsamples in this sample, must be at least 1.
	int32_t subsample_count;

	// The clear/encrypted mapping of each subsample in this sample. This must be
	// an array of \|subsample_count\| mappings.
	const SbDrmSubSampleMapping* subsample_mapping;
	} SbDrmSampleInfo;

	// A handle to a DRM system which can be used with either an SbDecoder or an
	// SbPlayer.
	typedef struct SbDrmSystemPrivate* SbDrmSystem;

	// A callback that will receive generated session update request when requested
	// from a SbDrmSystem. \|drm_system\| will be the DRM system that
	// SbDrmGenerateSessionUpdateRequest() was called on. \|context\| will be the same
	// context that was passed into the call to SbDrmCreateSystem().
	//
	// \|status\| is the status of the session request.
	//
	// \|type\| is the status of the session request.
	//
	// \|error_message\| may contain an optional error message when \|status\| isn't
	// \|kSbDrmStatusSuccess\| to provide more details about the error. It may be
	// NULL if \|status\| is \|kSbDrmStatusSuccess\| or if no error message can be
	// provided.
	// \|ticket\| will be the same ticket that was passed to
	// SbDrmGenerateSessionUpdateRequest() or \|kSbDrmTicketInvalid\| if the update
	// request was generated by the DRM system.
	//
	// \|session_id\| cannot be NULL when \|ticket\| is \|kSbDrmTicketInvalid\|, even when
	// there was an error generating the request. This allows Cobalt to find and
	// reject the correct Promise corresponding to the associated
	// SbDrmGenerateSessionUpdateRequest().
	typedef void (*SbDrmSessionUpdateRequestFunc)(SbDrmSystem drm_system,
	void* context,
	int ticket,
	SbDrmStatus status,
	SbDrmSessionRequestType type,
	const char* error_message,
	const void* session_id,
	int session_id_size,
	const void* content,
	int content_size,
	const char* url);

	// A callback for notifications that a session has been added, and subsequent
	// encrypted samples are actively ready to be decoded. \|drm_system\| will be the
	// DRM system that SbDrmUpdateSession() was called on. \|context\| will be the
	// same context passed into that call to SbDrmCreateSystem().
	//
	// \|ticket\| will be the same ticket that was passed to SbDrmUpdateSession().
	//
	// \|status\| is the status of the session request.
	//
	// \|error_message\| may contain an optional error message when \|status\| isn't
	// \|kSbDrmStatusSuccess\| to provide more details about the error. It may be
	// NULL if \|status\| is \|kSbDrmStatusSuccess\| or if no error message can be
	// provided.
	// \|succeeded\| is whether the session was successfully updated or not.
	typedef void (*SbDrmSessionUpdatedFunc)(SbDrmSystem drm_system,
	void* context,
	int ticket,
	SbDrmStatus status,
	const char* error_message,
	const void* session_id,
	int session_id_size);

	// A callback for notifications that the status of one or more keys in a session
	// has been changed. All keys of the session and their new status will be
	// passed along. Any keys not in the list is considered as deleted.
	typedef void (*SbDrmSessionKeyStatusesChangedFunc)(
	SbDrmSystem drm_system,
	void* context,
	const void* session_id,
	int session_id_size,
	int number_of_keys,
	const SbDrmKeyId* key_ids,
	const SbDrmKeyStatus* key_statuses);

	// A callback for signalling that a session has been closed by the SbDrmSystem
	typedef void (*SbDrmSessionClosedFunc)(SbDrmSystem drm_system,
	void* context,
	const void* session_id,
	int session_id_size);

	// A callback to notify the caller of SbDrmUpdateServerCertificate() whether the
	// update has been successfully updated or not.
	typedef void (*SbDrmServerCertificateUpdatedFunc)(SbDrmSystem drm_system,
	void* context,
	int ticket,
	SbDrmStatus status,
	const char* error_message);

	// --- Constants -------------------------------------------------------------

	// An invalid SbDrmSystem.
	#define kSbDrmSystemInvalid ((SbDrmSystem)NULL)

	// A ticket for callback invocations initiated by the DRM system.
	#define kSbDrmTicketInvalid kSbInvalidInt

	// --- Functions -------------------------------------------------------------

	// Indicates whether \|drm_system\| is a valid SbDrmSystem.
	static SB_C_FORCE_INLINE bool SbDrmSystemIsValid(SbDrmSystem drm) {
	return drm != kSbDrmSystemInvalid;
	}

	// Indicates whether \|ticket\| is a valid ticket.
	static SB_C_FORCE_INLINE bool SbDrmTicketIsValid(int ticket) {
	return ticket != kSbDrmTicketInvalid;
	}

	// Creates a new DRM system that can be used when constructing an SbPlayer or an
	// SbDecoder.
	//
	// This function returns \|kSbDrmSystemInvalid\| if \|key_system\| is unsupported.
	//
	// Also see the documentation of SbDrmGenerateSessionUpdateRequest() and
	// SbDrmUpdateSession() for more details.
	//
	// \|key_system\|: The DRM key system to be created. The value should be in the
	// form of "com.example.somesystem" as suggested by
	// https://w3c.github.io/encrypted-media/#key-system. All letters in the value
	// should be lowercase and will be matched exactly with known DRM key systems of
	// the platform.
	// \|context\|: A value passed when any of this function's callback parameters are
	// called.
	// \|update_request_callback\|: A function that is called every time after
	// SbDrmGenerateSessionUpdateRequest() is called.
	// \|session_updated_callback\|: A function that is called every time after
	// SbDrmUpdateSession() is called.
	// \|key_statuses_changed_callback\|: A function that can be called to indicate
	// that key statuses have changed.
	// \|server_certificate_updated_callback\|: A function that is called to report
	// whether the server certificate has been successfully updated. It is called
	// once and only once. It is possible that the callback is called before the
	// function returns.
	// \|session_closed_callback\|: A function that can be called to indicate that a
	// session has closed.
	// If \|NULL\| is passed for any of the callbacks (\|update_request_callback\|,
	// \|session_updated_callback\|, \|key_statuses_changed_callback\|,
	// \|server_certificate_updated_callback\|, or \|session_closed_callback\|), then
	// \|kSbDrmSystemInvalid\| must be returned.

	SB_EXPORT SbDrmSystem SbDrmCreateSystem(
	const char* key_system,
	void* context,
	SbDrmSessionUpdateRequestFunc update_request_callback,
	SbDrmSessionUpdatedFunc session_updated_callback,
	SbDrmSessionKeyStatusesChangedFunc key_statuses_changed_callback,
	SbDrmServerCertificateUpdatedFunc server_certificate_updated_callback,
	SbDrmSessionClosedFunc session_closed_callback);

	// Asynchronously generates a session update request payload for
	// \|initialization_data\|, of \|initialization_data_size\|, in case sensitive
	// \|type\|, extracted from the media stream, in \|drm_system\|'s key system.
	//
	// This function calls \|drm_system\|'s \|update_request_callback\| function,
	// which is defined when the DRM system is created by SbDrmCreateSystem. When
	// calling that function, this function either sends \|context\| (also from
	// \|SbDrmCreateSystem\|) and a populated request, or it sends NULL \|session_id\|
	// if an error occurred.
	//
	// \|drm_system\|'s \|context\| may be used to route callbacks back to an object
	// instance.
	//
	// Callbacks may be called either from the current thread before this function
	// returns or from another thread.
	//
	// \|drm_system\|: The DRM system that defines the key system used for the session
	// update request payload as well as the callback function that is called as a
	// result of the function being called. Must not be \|kSbDrmSystemInvalid\|.
	//
	// \|ticket\|: The opaque ID that allows to distinguish callbacks from multiple
	// concurrent calls to SbDrmGenerateSessionUpdateRequest(), which will be passed
	// to \|update_request_callback\| as-is. It is the responsibility of the caller to
	// establish ticket uniqueness, issuing multiple requests with the same ticket
	// may result in undefined behavior. The value \|kSbDrmTicketInvalid\| must not be
	// used.
	//
	// \|type\|: The case-sensitive type of the session update request payload. Must
	// not be NULL.
	// \|initialization_data\|: The data for which the session update
	// request payload is created. Must not be NULL.
	// \|initialization_data_size\|: The size of the session update request payload.
	SB_EXPORT void SbDrmGenerateSessionUpdateRequest(
	SbDrmSystem drm_system,
	int ticket,
	const char* type,
	const void* initialization_data,
	int initialization_data_size);

	// Update session with \|key\|, in \|drm_system\|'s key system, from the license
	// server response. Calls \|session_updated_callback\| with \|context\| and whether
	// the update succeeded. \|context\| may be used to route callbacks back to an
	// object instance. The \|key\| must not be NULL.
	//
	// \|drm_system\| must not be \|kSbDrmSystemInvalid\|.
	// \|ticket\| is the opaque ID that allows to distinguish callbacks from multiple
	// concurrent calls to SbDrmUpdateSession(), which will be passed to
	// \|session_updated_callback\| as-is. It is the responsibility of the caller to
	// establish ticket uniqueness, issuing multiple calls with the same ticket may
	// result in undefined behavior.
	//
	// Once the session is successfully updated, an SbPlayer or SbDecoder associated
	// with that DRM key system will be able to decrypt encrypted samples.
	//
	// \|drm_system\|'s \|session_updated_callback\| may called either from the current
	// thread before this function returns or from another thread.
	// The \|session_id\| must not be NULL.
	SB_EXPORT void SbDrmUpdateSession(SbDrmSystem drm_system,
	int ticket,
	const void* key,
	int key_size,
	const void* session_id,
	int session_id_size);

	// Clear any internal states/resources related to the specified \|session_id\|.
	//
	// \|drm_system\| must not be \|kSbDrmSystemInvalid\|.
	// \|session_id\| must not be NULL.
	SB_EXPORT void SbDrmCloseSession(SbDrmSystem drm_system,
	const void* session_id,
	int session_id_size);

	// Returns true if server certificate of \|drm_system\| can be updated via
	// SbDrmUpdateServerCertificate(). The return value should remain the same
	// during the life time of \|drm_system\|.
	//
	// \|drm_system\|: The DRM system to check if its server certificate is updatable.
	// Must not be \|kSbDrmSystemInvalid\|.
	SB_EXPORT bool SbDrmIsServerCertificateUpdatable(SbDrmSystem drm_system);

	// Update the server certificate of \|drm_system\|. The function can be called
	// multiple times. It is possible that a call to it happens before the callback
	// of a previous call is called.
	// Note that this function should only be called after
	// \|SbDrmIsServerCertificateUpdatable\| is called first and returned true.
	//
	// \|drm_system\|: The DRM system whose server certificate is being updated. Must
	// not be \|kSbDrmSystemInvalid\|.
	// \|ticket\|: The opaque ID that allows to distinguish callbacks from multiple
	// concurrent calls to SbDrmUpdateServerCertificate(), which will be passed to
	// \|server_certificate_updated_callback\| as-is. It is the responsibility of
	// the caller to establish ticket uniqueness, issuing multiple requests with
	// the same ticket may result in undefined behavior. The value
	// \|kSbDrmTicketInvalid\| must not be used.
	// \|certificate\|: Pointer to the server certificate data. Must not be NULL.
	// \|certificate_size\|: Size of the server certificate data.
	SB_EXPORT void SbDrmUpdateServerCertificate(SbDrmSystem drm_system,
	int ticket,
	const void* certificate,
	int certificate_size);

	// Get the metrics of the underlying drm system.
	//
	// When it is called on an implementation that supports drm system metrics, it
	// should return a pointer containing the metrics as a blob, encoded using url
	// safe base64 without padding and line wrapping, with the size of the encoded
	// result in \|size\| on return. For example, on Android API level 28 or later, it
	// should return the result of MediaDrm.getPropertyByteArray("metrics"), encoded
	// using url safe base64 without padding and line wrapping. On systems using
	// Widevine CE CDM with oemcrypto 16 or later, it should return the metrics
	// retrieved via Cdm::getMetrics(), encoded using url safe base64 without
	// padding and line wrapping. The returned pointer should remain valid and its
	// content should remain unmodified until the next time this function is called
	// on the associated \|drm_system\| or the \|drm_system\| is destroyed.
	//
	// When the metrics is empty on supported system, it should return a non-null
	// pointer with \|size\| set to 0.
	//
	// It should return NULL when there is no metrics support in the underlying drm
	// system, or when the drm system implementation fails to retrieve the metrics.
	//
	// \|drm_system\| must not be \|kSbDrmSystemInvalid\|.
	// \|size\| must not be NULL.
	SB_EXPORT const void* SbDrmGetMetrics(SbDrmSystem drm_system, int* size);

	// Destroys \|drm_system\|, which implicitly removes all keys installed in it and
	// invalidates all outstanding session update requests. A DRM system cannot be
	// destroyed unless any associated SbPlayer or SbDecoder has first been
	// destroyed.
	//
	// All callbacks are guaranteed to be finished when this function returns. As a
	// result, if this function is called from a callback that is passed to
	// SbDrmCreateSystem(), a deadlock will occur.
	//
	// \|drm_system\|: The DRM system to be destroyed. Must not be
	// \|kSbDrmSystemInvalid\|.
	SB_EXPORT void SbDrmDestroySystem(SbDrmSystem drm_system);

	#ifdef __cplusplus
	} // extern "C"
	#endif

	#endif // STARBOARD_DRM_H_