Add Decryptor interface.

media/crypto/aes_decryptor.h

 // 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_CRYPTO_AES_DECRYPTOR_H_
 #define MEDIA_CRYPTO_AES_DECRYPTOR_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
+#include "media/base/decryptor.h"
 #include "media/base/media_export.h"
 
 namespace crypto {
 class SymmetricKey;
 }
 
 namespace media {
 
-class DecoderBuffer;
-class DecryptorClient;
+// Clear Key Decryptor implementation that decrypts AES encrypted buffer.

[ddorwin, 2012/06/19 01:39:35]

nit: AES-encrypted (with dash)

[scherkus (not reviewing), 2012/06/19 03:03:24]

I'd remove mention of "Clear Key" -- that has more to do w/ how the key is
transported. The AesDecryptor could decrypt AES-encrypted content where the key
was transmitted by carrier pigeon :)

[xhwang, 2012/06/19 16:29:53]

Done.

[xhwang, 2012/06/19 16:29:53]

Done.

+class MEDIA_EXPORT AesDecryptor : public Decryptor {
+ public:
+  explicit AesDecryptor(DecryptorClient* client);
+  virtual ~AesDecryptor();
 
-// Decrypts AES encrypted buffer into unencrypted 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 synchronously.
-class MEDIA_EXPORT AesDecryptor {
- public:
-  enum KeyError {
-    kUnknownError = 1,
-    kClientError,
-    kServiceError,
-    kOutputError,
-    kHardwareChangeError,
-    kDomainError
-  };
-
-  // The AesDecryptor does not take ownership of the |client|. The |client|
-  // must be valid throughout the lifetime of the AesDecryptor.
-  explicit AesDecryptor(DecryptorClient* client);
-  ~AesDecryptor();
-
-  // Generates a key request. The result of this call will be reported via the
-  // client's KeyMessage() or KeyError() methods.
-  void GenerateKeyRequest(const std::string& key_system,
-                          const uint8* init_data,
-                          int init_data_length);
-
-  // 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.
-  // The result of this call will be reported via the client's KeyAdded(),
-  // KeyMessage() or KeyError() methods.
-  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);
-
-  // Cancels the key request specified by |session_id|.
-  void CancelKeyRequest(const std::string& key_system,
-                        const std::string& session_id);
-
-  // Decrypts the |input| buffer, which should not be NULL.
-  // Returns a DecoderBuffer with the decrypted data if decryption succeeded.
-  // Returns NULL if decryption failed.
-  scoped_refptr<DecoderBuffer> Decrypt(
-      const scoped_refptr<DecoderBuffer>& input);
+  // Decryptor implementation.
+  virtual void GenerateKeyRequest(const std::string& key_system,
+                                  const uint8* init_data,
+                                  int init_data_length) OVERRIDE;
+  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) OVERRIDE;
+  virtual void CancelKeyRequest(const std::string& key_system,
+                                const std::string& session_id) OVERRIDE;
+  virtual scoped_refptr<DecoderBuffer> Decrypt(
+      const scoped_refptr<DecoderBuffer>& input) OVERRIDE;
 
  private:
   // KeyMap owns the crypto::SymmetricKey* and must delete them when they are
   // not needed any more.
   typedef base::hash_map<std::string, crypto::SymmetricKey*> KeyMap;
 
   // Since only Decrypt() is called off the renderer thread, we only need to
   // protect |key_map_|, the only member variable that is shared between
   // Decrypt() and other methods.
   KeyMap key_map_;  // Protected by the |key_map_lock_|.
   base::Lock key_map_lock_;  // Protects the |key_map_|.
 
-  DecryptorClient* client_;
-
   // Make session ID unique per renderer by making it static.
   // TODO(xhwang): Make session ID more strictly defined if needed:
   // https://www.w3.org/Bugs/Public/show_bug.cgi?id=16739#c0
   static uint32 next_session_id_;
 
   DISALLOW_COPY_AND_ASSIGN(AesDecryptor);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CRYPTO_AES_DECRYPTOR_H_