Add CdmWrapper to support multiple CDM versions in CdmAdapter.

media/cdm/ppapi/cdm_wrapper.h

+// Copyright 2013 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_CDM_PPAPI_CDM_WRAPPER_H_
+#define MEDIA_CDM_PPAPI_CDM_WRAPPER_H_
+
+#include "base/basictypes.h"
+#include "media/cdm/ppapi/api/content_decryption_module.h"
+#include "media/cdm/ppapi/cdm_helpers.h"
+#include "ppapi/cpp/logging.h"
+
+namespace media {
+
+// CdmWrapper wraps different versions of ContentDecryptionModule interfaces and
+// exposes a common interface to the caller.
+//
+// The caller should call CdmWrapper::Create() to create a CDM instance.
+// CdmWrapper will first try to create a CDM instance that supports the latest
+// CDM interface (ContentDecryptionModule). If such an instance cannot be
+// created (e.g. an older CDM was loaded), CdmWrapper will try to create a CDM
+// that supports an older version of CDM interface (e.g.
+// ContentDecryptionModule_*). Internally CdmWrapper converts the CdmWrapper
+// calls to corresponding ContentDecryptionModule calls.
+//
+// Note that CdmWrapper interface always reflects the latest state of content
+// decryption related PPAPI APIs (e.g. pp::ContentDecryptor_Private).
+//
+// Since this file is highly templated and default implementations are short
+// (just a shim layer in most cases), everything is done in this header file.
+class CdmWrapper {
+ public:
+  static CdmWrapper* Create(const char* key_system,
+                            int key_system_size,
+                            GetCdmHostFunc get_cdm_host_func,
+                            void* user_data);
+
+  virtual ~CdmWrapper() {};
+
+  virtual cdm::Status GenerateKeyRequest(const char* type,
+                                         int type_size,
+                                         const uint8_t* init_data,
+                                         int init_data_size) = 0;
+  virtual cdm::Status AddKey(const char* session_id,
+                             int session_id_size,
+                             const uint8_t* key,
+                             int key_size,
+                             const uint8_t* key_id,
+                             int key_id_size) = 0;
+  virtual cdm::Status CancelKeyRequest(const char* session_id,
+                                       int session_id_size) = 0;
+  virtual void TimerExpired(void* context) = 0;
+  virtual cdm::Status Decrypt(const cdm::InputBuffer& encrypted_buffer,
+                              cdm::DecryptedBlock* decrypted_buffer) = 0;
+  virtual cdm::Status InitializeAudioDecoder(
+      const cdm::AudioDecoderConfig& audio_decoder_config) = 0;
+  virtual cdm::Status InitializeVideoDecoder(
+      const cdm::VideoDecoderConfig& video_decoder_config) = 0;
+  virtual void DeinitializeDecoder(cdm::StreamType decoder_type) = 0;
+  virtual void ResetDecoder(cdm::StreamType decoder_type) = 0;
+  virtual cdm::Status DecryptAndDecodeFrame(
+      const cdm::InputBuffer& encrypted_buffer,
+      cdm::VideoFrame* video_frame) = 0;
+  virtual cdm::Status DecryptAndDecodeSamples(
+      const cdm::InputBuffer& encrypted_buffer,
+      cdm::AudioFrames* audio_frames) = 0;
+
+ protected:
+  CdmWrapper() {};
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CdmWrapper);
+};
+
+// Template class that does the CdmWrapper -> CdmInterface conversion. Default
+// implementations are provided. Any methods that need special treatment should
+// be specialized.
+// TODO(xhwang): Remove CdmInterfaceVersion template parameter after we roll
+// CDM.h DEPS.
+template <class CdmInterface, int CdmInterfaceVersion>
+class CdmWrapperImpl : public CdmWrapper {
+ public:
+  static CdmWrapper* Create(const char* key_system,
+                            int key_system_size,
+                            GetCdmHostFunc get_cdm_host_func,
+                            void* user_data) {
+    void* cdm_instance = ::CreateCdmInstance(CdmInterfaceVersion,
+        key_system, key_system_size, get_cdm_host_func, user_data);
+    if (!cdm_instance)
+      return NULL;
+
+    return new CdmWrapperImpl<CdmInterface, CdmInterfaceVersion>(
+        static_cast<CdmInterface*>(cdm_instance));
+  }
+
+  virtual ~CdmWrapperImpl() {
+    cdm_->Destroy();
+  }
+
+  virtual cdm::Status GenerateKeyRequest(const char* type,
+                                         int type_size,
+                                         const uint8_t* init_data,
+                                         int init_data_size) OVERRIDE {
+    return cdm_->GenerateKeyRequest(type, type_size, init_data, init_data_size);
+  }
+
+  virtual cdm::Status AddKey(const char* session_id,
+                             int session_id_size,
+                             const uint8_t* key,
+                             int key_size,
+                             const uint8_t* key_id,
+                             int key_id_size) OVERRIDE {
+    return cdm_->AddKey(
+        session_id, session_id_size, key, key_size, key_id, key_id_size);
+  }
+
+  virtual cdm::Status CancelKeyRequest(const char* session_id,
+                                       int session_id_size) OVERRIDE {
+    return cdm_->CancelKeyRequest(session_id, session_id_size);
+  }
+
+  virtual void TimerExpired(void* context) OVERRIDE {
+    cdm_->TimerExpired(context);
+  }
+
+  virtual cdm::Status Decrypt(const cdm::InputBuffer& encrypted_buffer,
+                              cdm::DecryptedBlock* decrypted_buffer) OVERRIDE {
+    return cdm_->Decrypt(encrypted_buffer, decrypted_buffer);
+  }
+
+  virtual cdm::Status InitializeAudioDecoder(
+      const cdm::AudioDecoderConfig& audio_decoder_config) OVERRIDE {
+    return cdm_->InitializeAudioDecoder(audio_decoder_config);
+  }
+
+  virtual cdm::Status InitializeVideoDecoder(
+      const cdm::VideoDecoderConfig& video_decoder_config) OVERRIDE {
+    return cdm_->InitializeVideoDecoder(video_decoder_config);
+  }
+
+  virtual void DeinitializeDecoder(cdm::StreamType decoder_type) OVERRIDE {
+    cdm_->DeinitializeDecoder(decoder_type);
+  }
+
+  virtual void ResetDecoder(cdm::StreamType decoder_type) OVERRIDE {
+    cdm_->ResetDecoder(decoder_type);
+  }
+
+  virtual cdm::Status DecryptAndDecodeFrame(
+      const cdm::InputBuffer& encrypted_buffer,
+      cdm::VideoFrame* video_frame) OVERRIDE {
+    return cdm_->DecryptAndDecodeFrame(encrypted_buffer, video_frame);
+  }
+
+  virtual cdm::Status DecryptAndDecodeSamples(
+      const cdm::InputBuffer& encrypted_buffer,
+      cdm::AudioFrames* audio_frames) OVERRIDE {
+    return cdm_->DecryptAndDecodeSamples(encrypted_buffer, audio_frames);
+  }
+
+ private:
+  CdmWrapperImpl(CdmInterface* cdm) : cdm_(cdm) {
+    PP_DCHECK(cdm_);
+  }
+
+  CdmInterface* cdm_;
+
+  DISALLOW_COPY_AND_ASSIGN(CdmWrapperImpl);
+};
+
+// Specializations for old ContentDecryptionModule interfaces.
+// For example:
+
+// template <> cdm::Status CdmAdapterImpl<cdm::ContentDecryptionModule_1>::
+//     DecryptAndDecodeSamples(const cdm::InputBuffer& encrypted_buffer,
+//                             cdm::AudioFrames* audio_frames) {
+//   AudioFramesImpl audio_frames_1;
+//   cdm::Status status =
+//       cdm_->DecryptAndDecodeSamples(encrypted_buffer, &audio_frames_1);
+//   if (status != cdm::kSuccess)
+//     return status;
+//
+//   audio_frames->SetFrameBuffer(audio_frames_1.PassFrameBuffer());
+//   audio_frames->SetFormat(cdm::kAudioFormatS16);
+//   return cdm::kSuccess;
+// }
+
+CdmWrapper* CdmWrapper::Create(const char* key_system,
+                               int key_system_size,
+                               GetCdmHostFunc get_cdm_host_func,
+                               void* user_data) {
+  // Try to create the CDM using the latest CDM interface version.
+  CdmWrapper* cdm_wrapper =
+      CdmWrapperImpl<cdm::ContentDecryptionModule, cdm::kCdmInterfaceVersion>::
+          Create(key_system, key_system_size, get_cdm_host_func, user_data);
+
+  // Try to see if the CDM supports older version(s) of CDM interface(s).
+  // For example:
+  //
+  // if (cdm_wrapper)
+  //   return cdm_wrapper;
+  //
+  // cdm_wrapper = CdmWrapperImpl<cdm::ContentDecryptionModule_1>::Create(
+  //     key_system, key_system_size, get_cdm_host_func, user_data);
+
+  return cdm_wrapper;
+}
+
+}  // namespace media
+
+#endif  // MEDIA_CDM_PPAPI_CDM_WRAPPER_H_