Hook up CDM calls in CdmWrapper.

webkit/media/crypto/ppapi/cdm_wrapper.cc

Index: webkit/media/crypto/ppapi/cdm_wrapper.cc
diff --git a/webkit/media/crypto/ppapi/cdm_wrapper.cc b/webkit/media/crypto/ppapi/cdm_wrapper.cc
index 8faee29e035df911fece570efbaaa0eeb50b7715..2fdf6808fdc95cedb3fd85b611593691c61f0425 100644
--- a/webkit/media/crypto/ppapi/cdm_wrapper.cc
+++ b/webkit/media/crypto/ppapi/cdm_wrapper.cc
@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include <cstring>  // For std::memcpy.
+#include <cstring>  // For memcpy.
+#include <vector>
 
 #include "base/compiler_specific.h"  // For OVERRIDE.
 #include "ppapi/c/pp_errors.h"
@@ -20,27 +21,21 @@
 #include "ppapi/cpp/dev/buffer_dev.h"
 #include "ppapi/cpp/private/content_decryptor_private.h"
 #include "ppapi/utility/completion_callback_factory.h"
+#include "webkit/media/crypto/ppapi/content_decryption_module.h"
 
 namespace {
 
-struct DecryptorMessage {
-  DecryptorMessage() : media_error(0), system_code(0) {}
-  std::string key_system;
-  std::string session_id;
-  std::string default_url;
-  std::string message_data;
-  int32_t media_error;
-  int32_t system_code;
-};
-
-struct DecryptedBlock {
-  DecryptedBlock() {
-    std::memset(reinterpret_cast<void*>(&decrypted_block_info),
-                0,
-                sizeof(decrypted_block_info));
-  }
-  std::string decrypted_data;
-  PP_DecryptedBlockInfo decrypted_block_info;
+// This must be consistent with MediaKeyError defined in the spec:
+// http://goo.gl/rbdnR
+// TODO(xhwang): Add PP_MediaKeyError enum to avoid later static_cast in
+// PluginInstance.
+enum MediaKeyError {
+  kUnknownError = 1,
+  kClientError,
+  kServiceError,
+  kOutputError,
+  kHardwareChangeError,
+  kDomainError
 };
 
 bool IsMainThread() {
@@ -58,16 +53,25 @@ void CallOnMain(pp::CompletionCallback cb) {
 
 }  // namespace
 
+namespace webkit_media {
 
 // A wrapper class for abstracting away PPAPI interaction and threading for a
 // Content Decryption Module (CDM).
-class CDMWrapper : public pp::Instance,
+class CdmWrapper : public pp::Instance,
                    public pp::ContentDecryptor_Private {
  public:
-  CDMWrapper(PP_Instance instance, pp::Module* module);
-  virtual ~CDMWrapper() {}
+  CdmWrapper(PP_Instance instance, pp::Module* module);
+  virtual ~CdmWrapper();
+
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    return true;
+  }
 
   // PPP_ContentDecryptor_Private methods
+  // Note: As per comments in PPP_ContentDecryptor_Private, these calls should
+  // return false if the call was not forwarded to the CDM and should return
+  // true otherwise. Once the call reaches the CDM, the call result/status
+  // should be reported through the PPB_ContentDecryptor_Private interface.
   virtual bool GenerateKeyRequest(const std::string& key_system,
                                   pp::VarArrayBuffer init_data) OVERRIDE;
   virtual bool AddKey(const std::string& session_id,
@@ -77,163 +81,244 @@ class CDMWrapper : public pp::Instance,
   virtual bool Decrypt(
       pp::Buffer_Dev encrypted_buffer,
       const PP_EncryptedBlockInfo& encrypted_block_info) OVERRIDE;
-
   virtual bool DecryptAndDecode(
       pp::Buffer_Dev encrypted_buffer,
-      const PP_EncryptedBlockInfo& encrypted_block_info) OVERRIDE {
-    return false;
-  }
-
-  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
-    return true;
-  }
+      const PP_EncryptedBlockInfo& encrypted_block_info) OVERRIDE;
 
  private:
-  PP_Resource StringToBufferResource(const std::string& str);
+  // Creates a PP_Resource containing a PPB_Buffer_Impl, copies |data| into the
+  // buffer resource, and returns it. Returns a an invalid PP_Resource with an
+  // ID of 0 on failure. Upon success, the returned Buffer resource has a
+  // reference count of 1.
+  PP_Resource MakeBufferResource(const uint8_t* data, uint32_t data_size);
 
   // <code>PPB_ContentDecryptor_Private</code> dispatchers. These are passed to
   // <code>callback_factory_</code> to ensure that calls into
   // <code>PPP_ContentDecryptor_Private</code> are asynchronous.
-  void NeedKey(int32_t result, const DecryptorMessage& decryptor_message);
-  void KeyAdded(int32_t result, const DecryptorMessage& decryptor_message);
-  void KeyMessage(int32_t result, const DecryptorMessage& decryptor_message);
-  void KeyError(int32_t result, const DecryptorMessage& decryptor_message);
-  void DeliverBlock(int32_t result, const DecryptedBlock& decrypted_block);
-
-  pp::CompletionCallbackFactory<CDMWrapper> callback_factory_;
+  void KeyAdded(int32_t result, const std::string& session_id);
+  void KeyMessage(int32_t result, cdm::KeyMessage& key_message);
+  void KeyError(int32_t result, const std::string& session_id);
+  void DeliverBlock(int32_t result,
+                    const cdm::Status& status,
+                    cdm::OutputBuffer& output_buffer,
+                    const PP_DecryptTrackingInfo& tracking_info);
+
+  pp::CompletionCallbackFactory<CdmWrapper> callback_factory_;
+  cdm::ContentDecryptionModule* cdm_;
+  std::string key_system_;
 };
 
-CDMWrapper::CDMWrapper(PP_Instance instance,
-                       pp::Module* module)
+CdmWrapper::CdmWrapper(PP_Instance instance, pp::Module* module)
     : pp::Instance(instance),
-      pp::ContentDecryptor_Private(this) {
+      pp::ContentDecryptor_Private(this),
+      cdm_(NULL) {
   callback_factory_.Initialize(this);
 }
 
-bool CDMWrapper::GenerateKeyRequest(const std::string& key_system,
+CdmWrapper::~CdmWrapper() {
+  if (cdm_)
+    DestroyCdmInstance(cdm_);
+}
+
+bool CdmWrapper::GenerateKeyRequest(const std::string& key_system,
                                     pp::VarArrayBuffer init_data) {
-  PP_DCHECK(!key_system.empty() && init_data.ByteLength());
+  PP_DCHECK(!key_system.empty());
+
+  if (!cdm_) {
+    cdm_ = CreateCdmInstance();
+    if (!cdm_)
+      return false;
+  }
 
-  DecryptorMessage decryptor_message;
-  decryptor_message.key_system = key_system;
-  decryptor_message.session_id = "0";
-  decryptor_message.default_url = "http://www.google.com";
-  decryptor_message.message_data = "GenerateKeyRequest";
+  cdm::KeyMessage key_request;
+  cdm::Status status = cdm_->GenerateKeyRequest(
+      reinterpret_cast<const uint8_t*>(init_data.Map()),
+      init_data.ByteLength(),
+      &key_request);
+
+  if (status != cdm::kSuccess ||
+      !key_request.message ||
+      key_request.message_size == 0) {
+    CallOnMain(callback_factory_.NewCallback(&CdmWrapper::KeyError,
+                                             std::string()));
+    return true;
+  }
+
+  // TODO(xhwang): Remove unnecessary CallOnMain calls here and blow once we
+  // only support out-of-process.
+  // If running out-of-process, PPB calls will always behave asynchronously
+  // since IPC is involved. In that case, if we are already on main thread,
+  // we don't need to use CallOnMain to help us call PPB call on main thread,
+  // or to help call PPB asynchronously.
+  key_system_ = key_system;
+  CallOnMain(callback_factory_.NewCallback(&CdmWrapper::KeyMessage,
+                                           key_request));
 
-  CallOnMain(callback_factory_.NewCallback(&CDMWrapper::KeyMessage,
-                                           decryptor_message));
   return true;
 }
 
-bool CDMWrapper::AddKey(const std::string& session_id,
+bool CdmWrapper::AddKey(const std::string& session_id,
                         pp::VarArrayBuffer key,
                         pp::VarArrayBuffer init_data) {
-  const std::string key_string(reinterpret_cast<char*>(key.Map()),
-                               key.ByteLength());
-  const std::string init_data_string(reinterpret_cast<char*>(init_data.Map()),
-                                     init_data.ByteLength());
-
-  PP_DCHECK(!session_id.empty() && !key_string.empty());
-
-  DecryptorMessage decryptor_message;
-  decryptor_message.key_system = "AddKey";
-  decryptor_message.session_id = "0";
-  decryptor_message.default_url = "http://www.google.com";
-  decryptor_message.message_data = "AddKey";
-  CallOnMain(callback_factory_.NewCallback(&CDMWrapper::KeyAdded,
-                                           decryptor_message));
+  const uint8_t* key_ptr = reinterpret_cast<const uint8_t*>(key.Map());
+  int key_size = key.ByteLength();
+  const uint8_t* init_data_ptr =
+      reinterpret_cast<const uint8_t*>(init_data.Map());
+  int init_data_size = init_data.ByteLength();
+
+  if (!key_ptr || key_size <= 0 || init_data_ptr || init_data_size <= 0)

[ddorwin, 2012/08/27 17:33:54]

!init_data_ptr

[xhwang, 2012/08/27 18:07:26]

Done.

+    return false;
+
+  PP_DCHECK(cdm_);
+  cdm::Status status = cdm_->AddKey(session_id.data(), session_id.size(),
+                                    key_ptr, key_size,
+                                    init_data_ptr, init_data_size);
+
+  if (status != cdm::kSuccess) {
+    CallOnMain(callback_factory_.NewCallback(&CdmWrapper::KeyError,
+                                             session_id));
+    return true;
+  }
+
+  CallOnMain(callback_factory_.NewCallback(&CdmWrapper::KeyAdded, session_id));
   return true;
 }
 
-bool CDMWrapper::CancelKeyRequest(const std::string& session_id) {
-  // TODO(tomfinegan): cancel pending key request in CDM.
+bool CdmWrapper::CancelKeyRequest(const std::string& session_id) {
+  PP_DCHECK(cdm_);
 
-  PP_DCHECK(!session_id.empty());
+  cdm::Status status = cdm_->CancelKeyRequest(session_id.data(),
+                                              session_id.size());
 
-  DecryptorMessage decryptor_message;
-  decryptor_message.key_system = "CancelKeyRequest";
-  decryptor_message.session_id = "0";
-  decryptor_message.default_url = "http://www.google.com";
-  decryptor_message.message_data = "CancelKeyRequest";
+  if (status != cdm::kSuccess) {
+    CallOnMain(callback_factory_.NewCallback(&CdmWrapper::KeyError,
+                                             session_id));
+    return true;
+  }
 
-  CallOnMain(callback_factory_.NewCallback(&CDMWrapper::KeyMessage,
-                                           decryptor_message));
   return true;
 }
 
-bool CDMWrapper::Decrypt(pp::Buffer_Dev encrypted_buffer,
+bool CdmWrapper::Decrypt(pp::Buffer_Dev encrypted_buffer,
                          const PP_EncryptedBlockInfo& encrypted_block_info) {
   PP_DCHECK(!encrypted_buffer.is_null());
+  PP_DCHECK(cdm_);
+
+  // TODO(xhwang): Simplify the following data conversion.
+  cdm::InputBuffer input_buffer;
+  input_buffer.data = reinterpret_cast<uint8_t*>(encrypted_buffer.data());
+  input_buffer.data_size = encrypted_buffer.size();
+  input_buffer.data_offset = encrypted_block_info.data_offset;
+  input_buffer.key_id = encrypted_block_info.key_id;
+  input_buffer.key_id_size = encrypted_block_info.key_id_size;
+  input_buffer.iv = encrypted_block_info.iv;
+  input_buffer.iv_size = encrypted_block_info.iv_size;
+  input_buffer.checksum = encrypted_block_info.checksum;
+  input_buffer.checksum_size = encrypted_block_info.checksum_size;
+  input_buffer.num_subsamples = encrypted_block_info.num_subsamples;
+  std::vector<cdm::SubsampleEntry> subsamples;
+  for (uint32_t i = 0; i < encrypted_block_info.num_subsamples; ++i) {
+    subsamples.push_back(cdm::SubsampleEntry(
+        encrypted_block_info.subsamples[i].clear_bytes,
+        encrypted_block_info.subsamples[i].cipher_bytes));
+  }
+  input_buffer.subsamples = &subsamples[0];
+  input_buffer.timestamp = encrypted_block_info.tracking_info.timestamp;

[xhwang, 2012/08/25 00:04:32]

Hello all,

When I look at this code I hate myself :)

The CdmWrapper need to do a lot of translation between PP_Foo and cdm::Foo
types. But PP_Foo and cdm::Foo have so many in common. I wonder if we can
increase code reuse and reduce code like above. 

I have some brainstorming to start the discussion:

1, make CDM interface use pepper types directly.
   pros: minimum struct translation.
   cons: introduce dependency on pepper to CMD.
2, have some python code (similar to generator.py) to convert PP_Foo to cdm::Foo
automatically so that cdm::Foo is always in sync with PP_Foo and they always
share the same memory layout.
   pros: We can just do memcpy() or reinterpret_cast. No conversion needed.
   cons: more work to do.
3, of course we can also keep the current way.

Any thoughts?

[ddorwin, 2012/08/27 17:33:54]

My thoughts:
The point of CDM.h is to provide a (somewhat) stable API that is independent of
other Chrome code. That API can roll at a different time from the associated
Pepper APIs. If we were auto-generating the files, I don't think the above would
be true.

You can always move the above to a helper function and DCHECK the struct sizes
to make sure the helpers are still complete.

[xhwang, 2012/08/27 18:07:26]

Sounds good. I'll do the helper function later (tracked by the TODO on 207).

+
+  cdm::OutputBuffer output_buffer;
+  cdm::Status status = cdm_->Decrypt(input_buffer, &output_buffer);
+
+  CallOnMain(callback_factory_.NewCallback(
+      &CdmWrapper::DeliverBlock,
+      status,
+      output_buffer,
+      encrypted_block_info.tracking_info));
 
-  DecryptedBlock decrypted_block;
-  decrypted_block.decrypted_data = "Pretend I'm decrypted data!";
-  decrypted_block.decrypted_block_info.result = PP_DECRYPTRESULT_SUCCESS;
-  decrypted_block.decrypted_block_info.tracking_info =
-      encrypted_block_info.tracking_info;
-
-  // TODO(tomfinegan): This would end up copying a lot of data in the real
-  // implementation if we continue passing std::strings around. It *might* not
-  // be such a big deal w/a real CDM. We may be able to simply pass a pointer
-  // into the CDM. Otherwise we could look into using std::tr1::shared_ptr
-  // instead of passing a giant std::string filled with encrypted data.
-  CallOnMain(callback_factory_.NewCallback(&CDMWrapper::DeliverBlock,
-                                           decrypted_block));
   return true;
 }
 
-PP_Resource CDMWrapper::StringToBufferResource(const std::string& str) {
-  if (str.empty())
+bool CdmWrapper::DecryptAndDecode(
+    pp::Buffer_Dev encrypted_buffer,
+    const PP_EncryptedBlockInfo& encrypted_block_info) {
+  return false;
+}
+
+PP_Resource CdmWrapper::MakeBufferResource(const uint8_t* data,
+                                           uint32_t data_size) {
+  if (!data || !data_size)
     return 0;
 
-  pp::Buffer_Dev buffer(this, str.size());
+  pp::Buffer_Dev buffer(this, data_size);
   if (!buffer.data())
     return 0;
 
-  std::memcpy(buffer.data(), str.data(), str.size());
+  memcpy(buffer.data(), data, data_size);
+
   return buffer.detach();
 }
 
-void CDMWrapper::NeedKey(int32_t result,
-                         const DecryptorMessage& decryptor_message) {
-  const std::string& message_data = decryptor_message.message_data;
-  pp::VarArrayBuffer init_data(message_data.size());
-  std::memcpy(init_data.Map(), message_data.data(), message_data.size());
-  pp::ContentDecryptor_Private::NeedKey(decryptor_message.key_system,
-                                        decryptor_message.session_id,
-                                        init_data);
+void CdmWrapper::KeyAdded(int32_t result, const std::string& session_id) {
+  pp::ContentDecryptor_Private::KeyAdded(key_system_, session_id);
 }
 
-void CDMWrapper::KeyAdded(int32_t result,
-                          const DecryptorMessage& decryptor_message) {
-  pp::ContentDecryptor_Private::KeyAdded(decryptor_message.key_system,
-                                         decryptor_message.session_id);
+void CdmWrapper::KeyMessage(int32_t result,
+                            cdm::KeyMessage& key_message) {
+  pp::Buffer_Dev message_buffer(MakeBufferResource(key_message.message,
+                                                   key_message.message_size));
+  pp::ContentDecryptor_Private::KeyMessage(
+      key_system_,
+      std::string(key_message.session_id, key_message.session_id_size),
+      message_buffer,
+      std::string(key_message.default_url, key_message.default_url_size));
+
+  // TODO(xhwang): Fix this. This is not always safe as the memory is allocated
+  // in another shared object.
+  delete [] key_message.session_id;
+  key_message.session_id = NULL;
+  delete [] key_message.message;
+  key_message.message = NULL;
+  delete [] key_message.default_url;
+  key_message.default_url = NULL;
 }
 
-void CDMWrapper::KeyMessage(int32_t result,
-                            const DecryptorMessage& decryptor_message) {
-  pp::Buffer_Dev message_buffer(
-      StringToBufferResource(decryptor_message.message_data));
-  pp::ContentDecryptor_Private::KeyMessage(decryptor_message.key_system,
-                                           decryptor_message.session_id,
-                                           message_buffer,
-                                           decryptor_message.default_url);
+// TODO(xhwang): Support MediaKeyError (see spec: http://goo.gl/rbdnR) in CDM
+// interface and in this function.
+void CdmWrapper::KeyError(int32_t result, const std::string& session_id) {
+  pp::ContentDecryptor_Private::KeyError(key_system_,
+                                         session_id,
+                                         kUnknownError,
+                                         0);
 }
 
-void CDMWrapper::KeyError(int32_t result,
-                          const DecryptorMessage& decryptor_message) {
-  pp::ContentDecryptor_Private::KeyError(decryptor_message.key_system,
-                                         decryptor_message.session_id,
-                                         decryptor_message.media_error,
-                                         decryptor_message.system_code);
-}
+void CdmWrapper::DeliverBlock(int32_t result,
+                              const cdm::Status& status,
+                              cdm::OutputBuffer& output_buffer,
+                              const PP_DecryptTrackingInfo& tracking_info) {
+  pp::Buffer_Dev decrypted_buffer(MakeBufferResource(output_buffer.data,
+                                                     output_buffer.data_size));
 
-void CDMWrapper::DeliverBlock(int32_t result,
-                              const DecryptedBlock& decrypted_block) {
-  pp::Buffer_Dev decrypted_buffer(
-      StringToBufferResource(decrypted_block.decrypted_data));
-  pp::ContentDecryptor_Private::DeliverBlock(
-      decrypted_buffer,
-      decrypted_block.decrypted_block_info);
+  PP_DecryptedBlockInfo decrypted_block_info;
+  decrypted_block_info.tracking_info.request_id = tracking_info.request_id;
+  decrypted_block_info.tracking_info.timestamp = output_buffer.timestamp;
+
+  switch (status) {
+    case cdm::kSuccess:
+      decrypted_block_info.result = PP_DECRYPTRESULT_SUCCESS;
+      break;
+    case cdm::kErrorNoKey:
+      decrypted_block_info.result = PP_DECRYPTRESULT_DECRYPT_NOKEY;
+      break;
+    default:
+      decrypted_block_info.result = PP_DECRYPTRESULT_DECRYPT_ERROR;
+  }
+
+  pp::ContentDecryptor_Private::DeliverBlock(decrypted_buffer,
+                                             decrypted_block_info);
+
+  // TODO(xhwang): Fix this. This is not always safe as the memory is allocated
+  // in another shared object.
+  delete [] output_buffer.data;
+  output_buffer.data = NULL;
 }
 
 // This object is the global object representing this plugin library as long
@@ -244,15 +329,17 @@ class MyModule : public pp::Module {
   virtual ~MyModule() {}
 
   virtual pp::Instance* CreateInstance(PP_Instance instance) {
-    return new CDMWrapper(instance, this);
+    return new CdmWrapper(instance, this);
   }
 };
 
+}  // namespace webkit_media
+
 namespace pp {
 
 // Factory function for your specialization of the Module object.
 Module* CreateModule() {
-  return new MyModule();
+  return new webkit_media::MyModule();
 }
 
 }  // namespace pp