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 cdm::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 (uint32_t 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].cipher_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* const object_;
+};
+
+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;
+}
+
+cdm::ContentDecryptionModule* CreateCdmInstance() {
+  return new webkit_media::ClearKeyCdm();
+}
+
+void DestroyCdmInstance(cdm::ContentDecryptionModule* instance) {
+  delete instance;
+}
+
+const char* GetCdmVersion() {
+  return kClearKeyCdmVersion;
+}
+
+namespace webkit_media {
+
+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) {
+  // In the current implementation of AesDecryptor, NeedKey is not used.
+  // If no key is available to decrypt an input buffer, it returns kNoKey to
+  // the caller instead of firing NeedKey.
+  NOTREACHED();
+}
+
+ClearKeyCdm::ClearKeyCdm() : decryptor_(&client_) {}
+
+ClearKeyCdm::~ClearKeyCdm() {}
+
+ClearKeyCdm::Status 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) {
+  base::AutoLock auto_lock(lock_);
+  ScopedResetter<Client> auto_resetter(&client_);
+  decryptor_.GenerateKeyRequest("", init_data, init_data_size);
+
+  if (client_.status() != Client::kKeyMessage)
+    return kErrorUnknown;
+
+  // Client methods are called synchronously, so we can use client variables
+  // here.
+  *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);
+  return kSuccess;
+}
+
+ClearKeyCdm::Status ClearKeyCdm::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) {
+  base::AutoLock auto_lock(lock_);
+  ScopedResetter<Client> auto_resetter(&client_);
+  decryptor_.AddKey("", key, key_size, key_id, key_id_size,
+                    std::string(session_id, session_id_size));
+
+  // Client methods are called synchronously, so we can use client variables

[ddorwin, 2012/08/16 17:36:50]

Not sure what this is trying to say (that isn't already obvious from acquiring
client_lock_.

[xhwang, 2012/08/20 21:09:45]

Done.

+  // here.
+  if (client_.status() != Client::kKeyAdded)
+    return kErrorUnknown;
+
+  return kSuccess;
+}
+
+ClearKeyCdm::Status ClearKeyCdm::CancelKeyRequest(const char* session_id,
+                                                  int session_id_size) {
+  base::AutoLock auto_lock(lock_);
+  ScopedResetter<Client> auto_resetter(&client_);
+  decryptor_.CancelKeyRequest("", std::string(session_id, session_id_size));
+  return kSuccess;
+}
+
+static void CopyDecryptResults(
+    media::Decryptor::Status* status_copy,
+    scoped_refptr<media::DecoderBuffer>* buffer_copy,
+    media::Decryptor::Status status,
+    const scoped_refptr<media::DecoderBuffer>& buffer) {
+  *status_copy = status;
+  *buffer_copy = buffer;
+}
+
+ClearKeyCdm::Status ClearKeyCdm::Decrypt(
+    const char* session_id,
+    int session_id_size,
+    const cdm::InputBuffer& encrypted_buffer,
+    cdm::OutputBuffer* decrypted_buffer) {
+  scoped_refptr<media::DecoderBuffer> decoder_buffer =
+      CopyDecoderBufferFrom(encrypted_buffer);
+
+  // Callback is called synchronously, so we can use variables on the stack.
+  media::Decryptor::Status status;
+  scoped_refptr<media::DecoderBuffer> buffer;
+  decryptor_.Decrypt(decoder_buffer,
+                     base::Bind(&CopyDecryptResults, &status, &buffer));
+
+  if (status == media::Decryptor::kError)
+    return kErrorUnknown;
+
+  if (status == media::Decryptor::kNoKey)
+    return kErrorNoKey;
+
+  DCHECK(buffer);
+  int data_size = buffer->GetDataSize();
+  decrypted_buffer->data = AllocateAndCopy(buffer->GetData(), data_size);
+  decrypted_buffer->data_size = data_size;
+  decrypted_buffer->timestamp = buffer->GetTimestamp().InMilliseconds();
+  decrypted_buffer->duration = buffer->GetDuration().InMilliseconds();
+  return kSuccess;
+}
+
+}  // namespace webkit_media