Update CDM interface and add clear key CDM.

webkit/media/crypto/clear_key_cdm.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 "webkit/media/crypto/clear_key_cdm.h"
+
+#include <vector>
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/time.h"
+#include "media/base/decoder_buffer.h"
+
+static const char kClearKeyCdmVersion[] = "0.1.0.0";
+
+static scoped_refptr<media::DecoderBuffer> CopyDecoderBufferFrom(
+    const InputBuffer& input_buffer) {
+  scoped_refptr<media::DecoderBuffer> output_buffer =
+      media::DecoderBuffer::CopyFrom(input_buffer.data, input_buffer.data_size);
+
+  std::vector<media::SubsampleEntry> subsamples;
+  for (int i = 0; i < input_buffer.num_subsamples; ++i) {
+    media::SubsampleEntry subsample;
+    subsample.clear_bytes = input_buffer.subsamples[i].clear_bytes;
+    subsample.cypher_bytes = input_buffer.subsamples[i].cypher_bytes;
+    subsamples.push_back(subsample);
+  }
+
+  scoped_ptr<media::DecryptConfig> decrypt_config(new media::DecryptConfig(
+      std::string(reinterpret_cast<const char*>(input_buffer.key_id),
+                  input_buffer.key_id_size),
+      std::string(reinterpret_cast<const char*>(input_buffer.iv),
+                  input_buffer.key_id_size),
+      std::string(reinterpret_cast<const char*>(input_buffer.checksum),
+                  input_buffer.checksum_size),
+      input_buffer.data_offset,
+      subsamples));
+
+  output_buffer->SetDecryptConfig(decrypt_config.Pass());
+  output_buffer->SetTimestamp(
+      base::TimeDelta::FromMilliseconds(input_buffer.timestamp));
+  output_buffer->SetDuration(
+      base::TimeDelta::FromMilliseconds(input_buffer.duration));
+
+  return output_buffer;
+}
+
+template<typename Type>
+class ScopedResetter {
+ public:
+  explicit ScopedResetter(Type* object) : object_(object) {}
+  ~ScopedResetter() {
+    object_->Reset();
+  }
+
+ private:
+  Type* object_;

[ddorwin, 2012/08/15 20:15:00]

*const

[xhwang, 2012/08/16 02:32:40]

Done.

+};
+
+template<typename Type>
+static Type* AllocateAndCopy(const Type* data, int size) {
+  COMPILE_ASSERT(sizeof(Type) == 1, type_size_is_not_one);
+  Type* copy = new Type[size];
+  memcpy(copy, data, size);
+  return copy;
+}
+
+ContentDecryptionModule* CdmCreateInstance() {
+  return new ClearKeyCdm();
+}
+
+const char* CdmGetVersion() {
+  return kClearKeyCdmVersion;
+}
+
+ClearKeyCdm::Client::Client() : status_(kKeyError), key_message_length_(0) {}
+
+ClearKeyCdm::Client::~Client() {}
+
+void ClearKeyCdm::Client::Reset() {
+  status_ = kKeyError;
+  session_id_.clear();
+  key_message_.reset();
+  key_message_length_ = 0;
+  default_url_.clear();
+}
+
+void ClearKeyCdm::Client::KeyAdded(const std::string& key_system,
+                                   const std::string& session_id) {
+  status_ = kKeyAdded;
+  session_id_ = session_id;
+}
+
+void ClearKeyCdm::Client::KeyError(const std::string& key_system,
+                                   const std::string& session_id,
+                                   media::Decryptor::KeyError error_code,
+                                   int system_code) {
+  status_ = kKeyError;
+  session_id_ = session_id;
+}
+
+void ClearKeyCdm::Client::KeyMessage(const std::string& key_system,
+                                     const std::string& session_id,
+                                     scoped_array<uint8> message,
+                                     int message_length,
+                                     const std::string& default_url) {
+  status_ = kKeyMessage;
+  session_id_ = session_id;
+  key_message_ = message.Pass();
+  key_message_length_ = message_length;
+}
+
+void ClearKeyCdm::Client::NeedKey(const std::string& key_system,
+                                  const std::string& session_id,
+                                  scoped_array<uint8> init_data,
+                                  int init_data_length) {
+  NOTREACHED();
+}
+
+ClearKeyCdm::ClearKeyCdm()
+    : decryptor_(&client_),

[ddorwin, 2012/08/15 21:03:07]

Re-using the client means we cannot parallelize any of these calls. I don't
think Chrome is preventing this, so we probably can't do this. It seems fine,
especially for a test plugin, to just create a new client per call.
Unfortunately, AesDecryptor has Client is a member, so we can't do that.

One option is to collect callbacks in the Client then handle them all when a
synchronous call to AesDecryptor returns. That would work if this class was
asynchronous and we could just call callbacks, but it's not. Without an
additional identifier for each call, we can't pick the correct response (i.e.
which frame was decoded or the status from this call).

[xhwang, 2012/08/16 02:32:40]

Yes, we cannot parallelize these calls. Added comment before the declaration of
ClearKeyCdm. Need to figure this out later.

+      decryption_status_(media::Decryptor::kError) {
+}
+
+ClearKeyCdm::~ClearKeyCdm() {}
+
+void ClearKeyCdm::Reset() {

[ddorwin, 2012/08/15 20:15:00]

This doesn't reset the whole class, so I think this is inappropriate. What you
really need is OnScopeExit, which does what you want but for a random function.
I'm not sure if Chrome has something like this. If not, maybe you can change
your class to take a function pointer. However, if Chrome doesn't have something
like this, there may be a reason for that.

[xhwang, 2012/08/16 02:32:40]

Removed this method and made decryption_status_ and decrypted_buffer_ transient.

+  decryption_status_ = media::Decryptor::kError;
+  decrypted_buffer_ = NULL;
+}
+
+CdmStatus ClearKeyCdm::GenerateKeyRequest(const uint8_t* init_data,
+                                          int init_data_size,
+                                          char** session_id,
+                                          int* session_id_size,
+                                          uint8_t** key_request,
+                                          int* key_request_size,
+                                          char** default_url,
+                                          int* default_url_size) {
+  ScopedResetter<Client> _(&client_);

[Tom Finegan, 2012/08/15 20:02:42]

How about s/_(/resetter(/? :)

[xhwang, 2012/08/16 02:32:40]

Replaced with auto_resetter.

+  decryptor_.GenerateKeyRequest("", init_data, init_data_size);

[Tom Finegan, 2012/08/15 20:02:42]

Don't we have a placeholder key system name we can use? The wrapper (or the
underlying module) won't be happy w/this.

[Tom Finegan, 2012/08/15 20:22:24]

Err- disregard this, meant to remove it.

+
+  if (client_.status() != Client::kKeyMessage)
+    return kCdmStatusErrorUnknown;
+
+  *session_id_size = client_.session_id().size();
+  *session_id = AllocateAndCopy(client_.session_id().data(), *session_id_size);
+  *key_request_size = client_.key_message_length();
+  *key_request = AllocateAndCopy(client_.key_message(), *key_request_size);
+  *default_url_size = client_.default_url().size();
+  *default_url = AllocateAndCopy(client_.default_url().data(),
+                                 *default_url_size);
+

[Tom Finegan, 2012/08/15 20:02:42]

nit: can probably remove this empty line

[xhwang, 2012/08/16 02:32:40]

Done.

+  return kCdmStatusSuccess;
+}
+
+CdmStatus ClearKeyCdm::AddKey(const char* session_id,
+                              int session_id_size,
+                              const uint8_t* key,
+                              int key_size) {
+  ScopedResetter<Client> _(&client_);

[Tom Finegan, 2012/08/15 20:02:42]

Ditto on all of these. :)

[xhwang, 2012/08/16 02:32:40]

Done.

+  decryptor_.AddKey("", key, key_size, NULL, 0,
+                    std::string(session_id, session_id_size));
+  if (client_.status() != Client::kKeyAdded)
+    return kCdmStatusErrorUnknown;
+
+  return kCdmStatusSuccess;
+}
+
+CdmStatus ClearKeyCdm::CancelKeyRequest(const char* session_id,
+                                        int session_id_size) {
+  ScopedResetter<Client> _(&client_);
+  decryptor_.CancelKeyRequest("", std::string(session_id, session_id_size));
+
+  return kCdmStatusSuccess;
+}
+
+CdmStatus ClearKeyCdm::Decrypt(const char* session_id,
+                               int session_id_size,
+                               const InputBuffer &encrypted_buffer,
+                               OutputBuffer* decrypted_buffer) {
+  ScopedResetter<ClearKeyCdm> _(this);
+  scoped_refptr<media::DecoderBuffer> decoder_buffer =
+      CopyDecoderBufferFrom(encrypted_buffer);
+
+  decryptor_.Decrypt(decoder_buffer, base::Bind(&ClearKeyCdm::OnBufferDecrpted,
+                                                base::Unretained(this)));
+  if (decryption_status_ == media::Decryptor::kError)
+    return kCdmStatusErrorUnknown;
+
+  if (decryption_status_ == media::Decryptor::kNoKey)
+    return kCdmStatusErrorNoKey;
+
+  DCHECK(decrypted_buffer_);
+  int data_size = decrypted_buffer_->GetDataSize();
+  decrypted_buffer->data = AllocateAndCopy(decrypted_buffer_->GetData(),
+                                           data_size);
+  decrypted_buffer->data_size = data_size;
+  decrypted_buffer->timestamp =
+      decrypted_buffer_->GetTimestamp().InMilliseconds();
+  decrypted_buffer->duration =
+      decrypted_buffer_->GetDuration().InMilliseconds();
+
+  return kCdmStatusSuccess;
+}
+
+void ClearKeyCdm::OnBufferDecrpted(

[Tom Finegan, 2012/08/15 20:02:42]

s/Decrpted/Decrypted/

[xhwang, 2012/08/16 02:32:40]

This function is removed, but thanks for catching this :)

+    media::Decryptor::Status status,
+    const scoped_refptr<media::DecoderBuffer>& buffer) {
+  decryption_status_ = status;
+  decrypted_buffer_ = buffer;
+}