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// Copyright (c) 2012 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.
#ifndef MEDIA_BASE_DECRYPTOR_H_
#define MEDIA_BASE_DECRYPTOR_H_
#include <string>
#include "base/basictypes.h"
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "media/base/media_export.h"
namespace media {
class DecoderBuffer;
// Performs key operations and decrypts encrypted buffer.
// All public methods other than Decrypt() will be called on the renderer
// thread. Therefore, these calls should be fast and nonblocking, with key
// events fired asynchronously. Decrypt() will be called on the (video/audio)
// decoder thread.
class MEDIA_EXPORT Decryptor {
public:
enum KeyError {
kUnknownError = 1,
kClientError,
kServiceError,
kOutputError,
kHardwareChangeError,
kDomainError
};
enum Status {
kSuccess, // Decryption successfully completed. Decrypted buffer ready.
kNoKey, // No key is available to decrypt.
kError // Key is available but an error occurred during decryption.
};
Decryptor() {}
virtual ~Decryptor() {}
// Generates a key request for the |key_system| with |init_data| provided.
// Returns true if generating key request succeeded, false otherwise.
// Note: AddKey() and CancelKeyRequest() should only be called after
// GenerateKeyRequest() returns true.
virtual bool GenerateKeyRequest(const std::string& key_system,
const uint8* init_data,
int init_data_length) = 0;
// Adds a |key| to the |key_system|. The |key| is not limited to a decryption
// key. It can be any data that the key system accepts, such as a license.
// If multiple calls of this function set different keys for the same
// key ID, the older key will be replaced by the newer key.
virtual void AddKey(const std::string& key_system,
const uint8* key,
int key_length,
const uint8* init_data,
int init_data_length,
const std::string& session_id) = 0;
// Cancels the key request specified by |session_id|.
virtual void CancelKeyRequest(const std::string& key_system,
const std::string& session_id) = 0;
// Decrypts the |encrypted| buffer. The decrypt status and decrypted buffer
// are returned via the provided callback |decrypt_cb|. The |encrypted| buffer
// must not be NULL.
// Decrypt() should not be called until any previous DecryptCB has completed.
// Thus, only one DecryptCB may be pending at a time.
// Note that the callback maybe called synchronously or asynchronously.
//
// If the returned status is kSuccess, the |encrypted| buffer is successfully
// decrypted and the decrypted buffer is ready to be read.
// If the returned status is kNoKey, no decryption key is available to decrypt
// |encrypted| buffer. In this case the decrypted buffer must be NULL.
// If the returned status is kError, unexpected error has occurred. In this
// case the decrypted buffer must be NULL.
typedef base::Callback<void(Status,
const scoped_refptr<DecoderBuffer>&)> DecryptCB;
virtual void Decrypt(const scoped_refptr<DecoderBuffer>& encrypted,
const DecryptCB& decrypt_cb) = 0;
// Cancels the scheduled decryption operation and fires the pending DecryptCB
// immediately with kSuccess and NULL.
// Decrypt() should not be called again before the pending DecryptCB is fired.
virtual void CancelDecrypt() = 0;
private:
DISALLOW_COPY_AND_ASSIGN(Decryptor);
};
} // namespace media
#endif // MEDIA_BASE_DECRYPTOR_H_
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