Add PPAPI decryptor interfaces.

ppapi/examples/content_decryptor/content_decryptor.cc

+// 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.
+
+#include <cassert>
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/dev/ppb_buffer_dev.h"

[ddorwin, 2012/07/24 18:57:26]

Shouldn't need.

[Tom Finegan, 2012/07/25 02:00:07]

Done.

+#include "ppapi/c/dev/ppb_content_decryptor_dev.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/core.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/resource.h"
+#include "ppapi/cpp/var.h"
+#include "ppapi/cpp/dev/buffer_dev.h"
+#include "ppapi/cpp/dev/content_decryptor_dev.h"
+#include "ppapi/shared_impl/var.h"
+#include "ppapi/utility/completion_callback_factory.h"
+
+using ppapi::StringVar;
+
+namespace {
+
+struct DecryptorMessage {
+  std::string key_system;
+  std::string session_id;
+  std::string default_url;
+  std::string message_data;
+  uint16 media_error;
+  uint16 system_error;
+};
+
+DecryptorMessage DM_Empty() {

[ddorwin, 2012/07/24 18:57:26]

I think this is discouraged because of the static initialization of complex
types (std::string members). Maybe someone else can chime in.
The name needs to be changed.
You shouldn't need it, though, if you just add a constructor for the struct.

[Tom Finegan, 2012/07/25 02:00:07]

Done/added ctor.

+  DecryptorMessage decryptor_message = { "", "", "", "", 0, 0 };
+  return decryptor_message;
+}
+
+bool IsMainThread() {
+  return pp::Module::Get()->core()->IsMainThread();
+}
+
+void CallOnMain(pp::CompletionCallback cb) {
+  pp::Module::Get()->core()->CallOnMainThread(0, cb, PP_OK);
+}
+
+}  // namespace
+
+
+// A wrapper class responsible for managing interaction between the browser and
+// a Content Decryption Module (CDM).
+class CDMWrapper : public pp::Instance,
+                   public pp::ContentDecryptor_Dev {
+ public:
+  explicit CDMWrapper(PP_Instance instance, pp::Module* module);

[fgalligan1, 2012/07/24 04:33:41]

Don't need explicit.

[Tom Finegan, 2012/07/25 02:00:07]

Done/that's what I get for copy/pasting. :)

+  virtual ~CDMWrapper() {}
+
+  // PPP_ContentDecryptor_Dev methods
+  virtual bool GenerateKeyRequest(PP_Var key_system, PP_Resource init_data);
+  virtual bool AddKey(PP_Var session_id, PP_Resource key);
+  virtual bool CancelKeyRequest(PP_Var session_id);
+  virtual bool Decrypt(PP_Resource encrypted_block,
+                       PP_CompletionCallback callback);
+
+  virtual bool DecryptAndDecode(PP_Resource encrypted_block,
+                                PP_CompletionCallback callback) {
+    return false;
+  }
+
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    return true;
+  }
+
+ private:
+  PP_Resource StringToBufferResource(const std::string& str);
+
+  // <code>PPB_ContentDecryptor_Dev</code> dispatchers. These are passed to
+  // <code>factory_</code> to ensure that calls into
+  // <code>PPP_ContentDecryptor_Dev</code> are asynchronous.
+  void NeedKey(int32 result, const DecryptorMessage& decryptor_message);
+  void KeyAdded(int32 result, const DecryptorMessage& decryptor_message);
+  void KeyMessage(int32 result, const DecryptorMessage& decryptor_message);
+  void KeyError(int32 result, const DecryptorMessage& decryptor_message);
+  void DeliverBlock(int32 result, const DecryptorMessage& decryptor_message);
+
+  // Browser interfaces.
+  const PPB_Buffer_Dev* buffer_if_;
+  const PPB_ContentDecryptor_Dev* decryptor_if_;
+
+  pp::CompletionCallbackFactory<CDMWrapper> factory_;

[ddorwin, 2012/07/24 18:57:26]

Unless you see this named used elsewhere, you should prepend callback_ or cb_.
factory_ is ambiguous.

[Tom Finegan, 2012/07/25 02:00:07]

Stole it from:
http://code.google.com/p/chromium/source/search?q=CompletionCallbackFactory+f...

But I agree w/your comment. Changed to callback_factory_.

+
+  // TODO(tomfinegan): Should this be a list of session IDs? Needs removal after
+  // testing (I think!).

[ddorwin, 2012/07/24 18:57:26]

The EME API will eventually be based on object sessions. Whether we represent
that in this API or even internally is TBD.

+  std::string session_id_;
+
+  // TODO(tomfinegan): Should these be multimaps of session_id:key_system and

[ddorwin, 2012/07/24 18:57:26]

There is only one key system per CDM instance. (If they don't match the first
call, you can error out. See AesDecryptor.)

You'll need to map key IDs to keys. See AesDecryptor.

Keep in mind that session ID, keys, etc. are only relevant for clearkeyexternal
and will eventually need to be in a different .so. So you may want to at least
indicate which need to be moved, if not create a separate (i.e. pimpl) object
now.

+  // session_id:key? Or am I completely confused? :)
+  std::string key_;
+  std::string key_system_;
+};
+
+CDMWrapper::CDMWrapper(PP_Instance instance,
+                       pp::Module* module)
+    : pp::Instance(instance),
+      pp::ContentDecryptor_Dev(this) {
+  // TODO(tomfinegan): Replace with use of C++ interfaces when ready. Need to
+  // add the PPB interface methods to the cpp/ wrapper first.
+  decryptor_if_ = static_cast<const PPB_ContentDecryptor_Dev*>(
+      module->GetBrowserInterface(PPB_CONTENTDECRYPTOR_DEV_INTERFACE));
+  assert(decryptor_if_);
+  buffer_if_ = static_cast<const PPB_Buffer_Dev*>(

[ddorwin, 2012/07/24 18:57:26]

Just use the C++ interface. Should simplify things, including 124.

[Tom Finegan, 2012/07/25 02:00:07]

Done.

+      module->GetBrowserInterface(PPB_BUFFER_DEV_INTERFACE));
+  assert(buffer_if_);
+  factory_.Initialize(this);
+}
+
+bool CDMWrapper::GenerateKeyRequest(PP_Var key_system_arg,
+                                    PP_Resource init_data) {
+  if (init_data) {
+    pp::Buffer_Dev init_buffer(init_data);
+    if (!buffer_if_->IsBuffer(init_buffer.pp_resource()) ||
+        !init_buffer.data()) {
+      return false;
+    }
+  }
+
+  StringVar* key_system_var = StringVar::FromPPVar(key_system_arg);
+
+  // TODO(tomfinegan): confirm support for the key system.
+
+  DecryptorMessage decryptor_message = DM_Empty();

[ddorwin, 2012/07/24 18:57:26]

You're just using an assignment operator here. Instead, create a proper
constructor for DecryptorMessage.

[Tom Finegan, 2012/07/25 02:00:07]

Done.

+  key_system_ = key_system_var->value();
+  decryptor_message.key_system = key_system_;
+  session_id_ = "12345";
+  decryptor_message.session_id = session_id_;
+  decryptor_message.default_url = "http://www.google.com";
+  decryptor_message.message_data = "key request";
+
+  CallOnMain(factory_.NewCallback(&CDMWrapper::KeyMessage, decryptor_message));
+  return true;
+}
+
+bool CDMWrapper::AddKey(PP_Var session_id_var, PP_Resource key) {
+  std::string session_id = StringVar::FromPPVar(session_id_var)->value();
+
+  pp::Buffer_Dev key_buffer(key);
+  if (!buffer_if_->IsBuffer(key) || !key_buffer.data())

[ddorwin, 2012/07/24 18:57:26]

Shouldn't you be checking IsBuffer(key_buffer.pp_resource)? Sure, it _should_ be
the same, but better to check what you're going to use.

[Tom Finegan, 2012/07/25 02:00:07]

Removed in favor of using the cpp wrapper.

+    return false;
+
+  key_.assign(reinterpret_cast<char*>(key_buffer.data()), key_buffer.size());
+
+  DecryptorMessage decryptor_message = DM_Empty();

[ddorwin, 2012/07/24 18:57:26]

same

[Tom Finegan, 2012/07/25 02:00:07]

Ditto.

+  // TODO(tomfinegan): determine where the key system is coming from at this
+  // point.
+  decryptor_message.key_system = "look up in multimap maybe?";

[ddorwin, 2012/07/24 18:57:26]

just use the member - it can't change.

[Tom Finegan, 2012/07/25 02:00:07]

Done.

+  decryptor_message.session_id = session_id;
+  CallOnMain(factory_.NewCallback(&CDMWrapper::KeyAdded, decryptor_message));
+  return true;
+}
+
+bool CDMWrapper::CancelKeyRequest(PP_Var session_id_var) {
+  // TODO(tomfinegan): This seems extremely heavy handed-- will one CDMWrapper
+  // instance ever have multiple sessions?

[ddorwin, 2012/07/24 18:57:26]

Yes.
This is more for teardown. Not sure we need to stop sending events. Maybe
WebKit/Chrome should handle ignoring in-flight callbacks.

[Tom Finegan, 2012/07/25 02:00:07]

Removed.

+  factory_.CancelAll();
+
+  std::string session_id = StringVar::FromPPVar(session_id_var)->value();
+
+  DecryptorMessage decryptor_message = DM_Empty();

[ddorwin, 2012/07/24 18:57:26]

There is no message to send for cancelKeyRequest.

[Tom Finegan, 2012/07/25 02:00:07]

Ah, ok. Removed. I'll read over the EME stuff some more-- I probably should have
known that already.

+  decryptor_message.session_id = session_id;
+  decryptor_message.message_data = "Request cancelled for session ";
+  decryptor_message.message_data.append(session_id);
+
+  CallOnMain(factory_.NewCallback(&CDMWrapper::KeyMessage, decryptor_message));
+  return true;
+}
+
+bool CDMWrapper::Decrypt(PP_Resource encrypted_block,
+                         PP_CompletionCallback callback) {
+  pp::Buffer_Dev block_buffer(encrypted_block);
+  if (!buffer_if_->IsBuffer(block_buffer.pp_resource()) ||
+      !block_buffer.data()) {
+    return false;
+  }
+
+  const std::string kDummyDecryptedData = "Pretend I'm decrypted data!";
+  PP_Resource decrypted_resource = StringToBufferResource(kDummyDecryptedData);
+  if (!decrypted_resource)
+    return false;
+
+  decryptor_if_->DeliverBlock(pp_instance(), decrypted_resource, callback);
+  return true;
+}
+
+PP_Resource CDMWrapper::StringToBufferResource(const std::string& str) {
+  if (str.empty())
+    return 0;
+
+  pp::Buffer_Dev buffer(this, str.size());
+  if (!buffer_if_->IsBuffer(buffer.pp_resource()) || !buffer.data())
+    return 0;
+
+  memcpy(buffer.data(), str.data(), str.size());
+  return buffer.detach();
+}
+
+void CDMWrapper::NeedKey(int32 result,
+                         const DecryptorMessage& decryptor_message) {
+  PP_Var key_system = StringVar::StringToPPVar(decryptor_message.key_system);
+  PP_Var session_id = StringVar::StringToPPVar(decryptor_message.session_id);
+  PP_Resource init_data =
+      StringToBufferResource(decryptor_message.message_data);
+  decryptor_if_->NeedKey(pp_instance(), key_system, session_id, init_data);
+}
+
+void CDMWrapper::KeyAdded(int32 result,
+                          const DecryptorMessage& decryptor_message) {
+  PP_Var key_system = StringVar::StringToPPVar(decryptor_message.key_system);
+  PP_Var session_id = StringVar::StringToPPVar(decryptor_message.session_id);
+  decryptor_if_->KeyAdded(pp_instance(), key_system, session_id);
+}
+
+void CDMWrapper::KeyMessage(int32 result,
+                            const DecryptorMessage& decryptor_message) {
+  PP_Var key_system = StringVar::StringToPPVar(decryptor_message.key_system);
+  PP_Var session_id = StringVar::StringToPPVar(decryptor_message.session_id);
+  PP_Resource message =
+      StringToBufferResource(decryptor_message.message_data);
+  PP_Var default_url =
+      StringVar::StringToPPVar(decryptor_message.default_url);
+  decryptor_if_->KeyMessage(pp_instance(),
+                            key_system,
+                            session_id,
+                            message,
+                            default_url);
+}
+
+void CDMWrapper::KeyError(int32 result,
+                          const DecryptorMessage& decryptor_message) {
+  PP_Var key_system = StringVar::StringToPPVar(decryptor_message.key_system);
+  PP_Var session_id = StringVar::StringToPPVar(decryptor_message.session_id);
+  decryptor_if_->KeyError(pp_instance(),
+                          key_system,
+                          session_id,
+                          decryptor_message.media_error,

[ddorwin, 2012/07/24 18:57:26]

You could do all of the params in these calls like this. Just indent four from
the current indentation (two) on the line after KeyError( and it should fit.

+                          decryptor_message.system_error);
+}
+
+void CDMWrapper::DeliverBlock(int32 result,
+                              const DecryptorMessage& decryptor_message) {
+}
+
+// This object is the global object representing this plugin library as long
+// as it is loaded.
+class MyModule : public pp::Module {
+ public:
+  MyModule() : pp::Module() {}
+  virtual ~MyModule() {}
+
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new CDMWrapper(instance, this);
+  }
+};
+
+namespace pp {
+
+// Factory function for your specialization of the Module object.
+Module* CreateModule() {
+  return new MyModule();
+}
+
+}  // namespace pp