shaka-packager/media/base/widevine_encryption_key_sou...

107 lines
4.2 KiB
C++

// Copyright 2014 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#ifndef MEDIA_BASE_WIDEVINE_ENCRYPTION_KEY_SOURCE_H_
#define MEDIA_BASE_WIDEVINE_ENCRYPTION_KEY_SOURCE_H_
#include <map>
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "media/base/closure_thread.h"
#include "media/base/encryption_key_source.h"
#include "media/base/producer_consumer_queue.h"
namespace media {
/// A negative crypto period index disables key rotation.
static const int kDisableKeyRotation = -1;
class HttpFetcher;
class RequestSigner;
/// WidevineEncryptionKeySource talks to the Widevine encryption service to
/// acquire the encryption keys.
class WidevineEncryptionKeySource : public EncryptionKeySource {
public:
/// @param server_url is the Widevine common encryption server url.
/// @param content_id the unique id identify the content to be encrypted.
/// @param signer signs the request message. It should not be NULL.
/// @param first_crypto_period_index indicates the starting crypto period
/// index. Set it to kDisableKeyRotation to disable key rotation.
WidevineEncryptionKeySource(const std::string& server_url,
const std::string& content_id,
scoped_ptr<RequestSigner> signer,
int first_crypto_period_index);
virtual ~WidevineEncryptionKeySource();
/// @name EncryptionKeySource implementation overrides.
/// @{
virtual Status GetKey(TrackType track_type, EncryptionKey* key) OVERRIDE;
virtual Status GetCryptoPeriodKey(uint32 crypto_period_index,
TrackType track_type,
EncryptionKey* key) OVERRIDE;
/// @}
/// Inject an @b HttpFetcher object, mainly used for testing.
/// @param http_fetcher points to the @b HttpFetcher object to be injected.
void set_http_fetcher(scoped_ptr<HttpFetcher> http_fetcher);
private:
typedef std::map<TrackType, EncryptionKey*> EncryptionKeyMap;
class RefCountedEncryptionKeyMap;
// Internal routine for getting keys.
Status GetKeyInternal(uint32 crypto_period_index,
TrackType track_type,
EncryptionKey* key);
// The closure task to fetch keys repeatedly.
void FetchKeysTask();
// Fetch keys from server.
Status FetchKeys(uint32 first_crypto_period_index);
// Fill |request| with necessary fields for Widevine encryption request.
// |request| should not be NULL.
void FillRequest(const std::string& content_id,
uint32 first_crypto_period_index,
std::string* request);
// Sign and properly format |request|.
// |signed_request| should not be NULL. Return OK on success.
Status SignRequest(const std::string& request, std::string* signed_request);
// Decode |response| from JSON formatted |raw_response|.
// |response| should not be NULL.
bool DecodeResponse(const std::string& raw_response, std::string* response);
// Extract encryption key from |response|, which is expected to be properly
// formatted. |transient_error| will be set to true if it fails and the
// failure is because of a transient error from the server. |transient_error|
// should not be NULL.
bool ExtractEncryptionKey(const std::string& response, bool* transient_error);
// Push the keys to the key pool.
bool PushToKeyPool(EncryptionKeyMap* encryption_key_map);
// The fetcher object used to fetch HTTP response from server.
// It is initialized to a default fetcher on class initialization.
// Can be overridden using set_http_fetcher for testing or other purposes.
scoped_ptr<HttpFetcher> http_fetcher_;
std::string server_url_;
std::string content_id_;
scoped_ptr<RequestSigner> signer_;
const bool key_rotation_enabled_;
const uint32 crypto_period_count_;
uint32 first_crypto_period_index_;
ClosureThread key_production_thread_;
ProducerConsumerQueue<scoped_refptr<RefCountedEncryptionKeyMap> > key_pool_;
Status common_encryption_request_status_;
DISALLOW_COPY_AND_ASSIGN(WidevineEncryptionKeySource);
};
} // namespace media
#endif // MEDIA_BASE_WIDEVINE_ENCRYPTION_KEY_SOURCE_H_