Move EME code out of WebMediaPlayerImpl.

content/renderer/media/crypto/encrypted_media_support_impl.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.

[ddorwin, 2014/08/22 21:08:48]

Is this far too different from WMPI.cc to get any useful diff (even with a low
--similarity)?

[acolwell GONE FROM CHROMIUM, 2014/08/22 23:20:22]

I don't know what you mean. Most of this code is simply copy and pasted with a
s/WebMediaPlayerImpl/EncryptedMediaPlayerImpl/g

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/media/crypto/encrypted_media_support_impl.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/metrics/histogram.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "content/renderer/media/crypto/key_systems.h"
+#include "content/renderer/media/webcontentdecryptionmodule_impl.h"
+#include "content/renderer/pepper/pepper_webplugin_impl.h"
+#include "media/base/bind_to_current_loop.h"
+#include "third_party/WebKit/public/platform/WebContentDecryptionModule.h"
+#include "third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h"
+#include "third_party/WebKit/public/platform/WebMediaPlayerClient.h"
+#include "third_party/WebKit/public/web/WebDocument.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
+#include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
+
+#if defined(ENABLE_PEPPER_CDMS)
+#include "content/renderer/media/crypto/pepper_cdm_wrapper_impl.h"
+#endif
+
+using blink::WebMediaPlayer;
+using blink::WebMediaPlayerClient;
+using blink::WebString;
+
+namespace content {
+
+#define BIND_TO_RENDER_LOOP(function)            \
+  (media::BindToCurrentLoop(base::Bind(function, AsWeakPtr())))
+
+#define BIND_TO_RENDER_LOOP1(function, arg1)     \
+  (media::BindToCurrentLoop(base::Bind(function, AsWeakPtr(), arg1)))
+
+
+// Prefix for histograms related to Encrypted Media Extensions.
+static const char* kMediaEme = "Media.EME.";
+
+// Used for calls to decryptor_ready_cb where the result can be ignored.
+static void DoNothing(bool success) {
+}
+
+// Convert a WebString to ASCII, falling back on an empty string in the case
+// of a non-ASCII string.
+static std::string ToASCIIOrEmpty(const WebString& string) {
+  return base::IsStringASCII(string) ? base::UTF16ToASCII(string)
+                                     : std::string();
+}
+
+// Helper functions to report media EME related stats to UMA. They follow the
+// convention of more commonly used macros UMA_HISTOGRAM_ENUMERATION and
+// UMA_HISTOGRAM_COUNTS. The reason that we cannot use those macros directly is
+// that UMA_* macros require the names to be constant throughout the process'
+// lifetime.
+static void EmeUMAHistogramEnumeration(const std::string& key_system,
+                                       const std::string& method,
+                                       int sample,
+                                       int boundary_value) {
+  base::LinearHistogram::FactoryGet(
+      kMediaEme + KeySystemNameForUMA(key_system) + "." + method,
+      1, boundary_value, boundary_value + 1,
+      base::Histogram::kUmaTargetedHistogramFlag)->Add(sample);
+}
+
+static void EmeUMAHistogramCounts(const std::string& key_system,
+                                  const std::string& method,
+                                  int sample) {
+  // Use the same parameters as UMA_HISTOGRAM_COUNTS.
+  base::Histogram::FactoryGet(
+      kMediaEme + KeySystemNameForUMA(key_system) + "." + method,
+      1, 1000000, 50, base::Histogram::kUmaTargetedHistogramFlag)->Add(sample);
+}
+
+// Helper enum for reporting generateKeyRequest/addKey histograms.
+enum MediaKeyException {
+  kUnknownResultId,
+  kSuccess,
+  kKeySystemNotSupported,
+  kInvalidPlayerState,
+  kMaxMediaKeyException
+};
+
+static MediaKeyException MediaKeyExceptionForUMA(
+    WebMediaPlayer::MediaKeyException e) {
+  switch (e) {
+    case WebMediaPlayer::MediaKeyExceptionKeySystemNotSupported:
+      return kKeySystemNotSupported;
+    case WebMediaPlayer::MediaKeyExceptionInvalidPlayerState:
+      return kInvalidPlayerState;
+    case WebMediaPlayer::MediaKeyExceptionNoError:
+      return kSuccess;
+    default:
+      return kUnknownResultId;
+  }
+}
+
+// Helper for converting |key_system| name and exception |e| to a pair of enum
+// values from above, for reporting to UMA.
+static void ReportMediaKeyExceptionToUMA(const std::string& method,
+                                         const std::string& key_system,
+                                         WebMediaPlayer::MediaKeyException e) {
+  MediaKeyException result_id = MediaKeyExceptionForUMA(e);
+  DCHECK_NE(result_id, kUnknownResultId) << e;
+  EmeUMAHistogramEnumeration(
+      key_system, method, result_id, kMaxMediaKeyException);
+}
+
+// Guess the type of |init_data|. This is only used to handle some corner cases
+// so we keep it as simple as possible without breaking major use cases.
+static std::string GuessInitDataType(const unsigned char* init_data,
+                                     unsigned init_data_length) {
+  // Most WebM files use KeyId of 16 bytes. MP4 init data are always >16 bytes.
+  if (init_data_length == 16)
+    return "video/webm";
+
+  return "video/mp4";
+}
+
+scoped_ptr<EncryptedMediaSupport> EncryptedMediaSupport::create(
+    blink::WebMediaPlayerClient* client) {
+  return scoped_ptr<EncryptedMediaSupport>(
+      new EncryptedMediaSupportImpl(client));
+}
+
+EncryptedMediaSupportImpl::EncryptedMediaSupportImpl(
+    blink::WebMediaPlayerClient* client)
+    : client_(client),
+      web_cdm_(NULL) {
+}
+
+EncryptedMediaSupportImpl::~EncryptedMediaSupportImpl() {
+}
+
+WebMediaPlayer::MediaKeyException
+EncryptedMediaSupportImpl::generateKeyRequest(
+    blink::WebLocalFrame* frame,
+    const WebString& key_system,
+    const unsigned char* init_data,
+    unsigned init_data_length) {
+  DVLOG(1) << "generateKeyRequest: " << base::string16(key_system) << ": "
+           << std::string(reinterpret_cast<const char*>(init_data),
+                          static_cast<size_t>(init_data_length));
+
+  std::string ascii_key_system =
+      GetUnprefixedKeySystemName(ToASCIIOrEmpty(key_system));
+
+  WebMediaPlayer::MediaKeyException e =
+      GenerateKeyRequestInternal(frame, ascii_key_system, init_data,
+                                 init_data_length);
+  ReportMediaKeyExceptionToUMA("generateKeyRequest", ascii_key_system, e);
+  return e;
+}
+
+
+WebMediaPlayer::MediaKeyException
+EncryptedMediaSupportImpl::GenerateKeyRequestInternal(
+    blink::WebLocalFrame* frame,
+    const std::string& key_system,
+    const unsigned char* init_data,
+    unsigned init_data_length) {
+  if (!IsConcreteSupportedKeySystem(key_system))
+    return WebMediaPlayer::MediaKeyExceptionKeySystemNotSupported;
+
+  // We do not support run-time switching between key systems for now.
+  if (current_key_system_.empty()) {
+    if (!proxy_decryptor_) {
+      proxy_decryptor_.reset(new ProxyDecryptor(
+#if defined(ENABLE_PEPPER_CDMS)
+          // Create() must be called synchronously as |frame| may not be
+          // valid afterwards.
+          base::Bind(&PepperCdmWrapperImpl::Create, frame),
+#elif defined(ENABLE_BROWSER_CDMS)
+#error Browser side CDM in WMPI for prefixed EME API not supported yet.
+#endif
+          BIND_TO_RENDER_LOOP(&EncryptedMediaSupportImpl::OnKeyAdded),
+          BIND_TO_RENDER_LOOP(&EncryptedMediaSupportImpl::OnKeyError),
+          BIND_TO_RENDER_LOOP(&EncryptedMediaSupportImpl::OnKeyMessage)));
+    }
+
+    GURL security_origin(frame->document().securityOrigin().toString());
+    if (!proxy_decryptor_->InitializeCDM(key_system, security_origin))
+      return WebMediaPlayer::MediaKeyExceptionKeySystemNotSupported;
+
+    if (proxy_decryptor_ && !decryptor_ready_cb_.is_null()) {
+      base::ResetAndReturn(&decryptor_ready_cb_)
+          .Run(proxy_decryptor_->GetDecryptor(), base::Bind(DoNothing));
+    }
+
+    current_key_system_ = key_system;
+  } else if (key_system != current_key_system_) {
+    return WebMediaPlayer::MediaKeyExceptionInvalidPlayerState;
+  }
+
+  std::string init_data_type = init_data_type_;
+  if (init_data_type.empty())
+    init_data_type = GuessInitDataType(init_data, init_data_length);
+
+  // TODO(xhwang): We assume all streams are from the same container (thus have
+  // the same "type") for now. In the future, the "type" should be passed down
+  // from the application.
+  if (!proxy_decryptor_->GenerateKeyRequest(
+           init_data_type, init_data, init_data_length)) {
+    current_key_system_.clear();
+    return WebMediaPlayer::MediaKeyExceptionKeySystemNotSupported;
+  }
+
+  return WebMediaPlayer::MediaKeyExceptionNoError;
+}
+
+WebMediaPlayer::MediaKeyException EncryptedMediaSupportImpl::addKey(
+    const WebString& key_system,
+    const unsigned char* key,
+    unsigned key_length,
+    const unsigned char* init_data,
+    unsigned init_data_length,
+    const WebString& session_id) {
+  DVLOG(1) << "addKey: " << base::string16(key_system) << ": "
+           << std::string(reinterpret_cast<const char*>(key),
+                          static_cast<size_t>(key_length)) << ", "
+           << std::string(reinterpret_cast<const char*>(init_data),
+                          static_cast<size_t>(init_data_length)) << " ["
+           << base::string16(session_id) << "]";
+
+  std::string ascii_key_system =
+      GetUnprefixedKeySystemName(ToASCIIOrEmpty(key_system));
+  std::string ascii_session_id = ToASCIIOrEmpty(session_id);
+
+  WebMediaPlayer::MediaKeyException e = AddKeyInternal(ascii_key_system,
+                                                       key,
+                                                       key_length,
+                                                       init_data,
+                                                       init_data_length,
+                                                       ascii_session_id);
+  ReportMediaKeyExceptionToUMA("addKey", ascii_key_system, e);
+  return e;
+}
+
+WebMediaPlayer::MediaKeyException EncryptedMediaSupportImpl::AddKeyInternal(
+    const std::string& key_system,
+    const unsigned char* key,
+    unsigned key_length,
+    const unsigned char* init_data,
+    unsigned init_data_length,
+    const std::string& session_id) {
+  DCHECK(key);
+  DCHECK_GT(key_length, 0u);
+
+  if (!IsConcreteSupportedKeySystem(key_system))
+    return WebMediaPlayer::MediaKeyExceptionKeySystemNotSupported;
+
+  if (current_key_system_.empty() || key_system != current_key_system_)
+    return WebMediaPlayer::MediaKeyExceptionInvalidPlayerState;
+
+  proxy_decryptor_->AddKey(
+      key, key_length, init_data, init_data_length, session_id);
+  return WebMediaPlayer::MediaKeyExceptionNoError;
+}
+
+WebMediaPlayer::MediaKeyException EncryptedMediaSupportImpl::cancelKeyRequest(
+    const WebString& key_system,
+    const WebString& session_id) {
+  DVLOG(1) << "cancelKeyRequest: " << base::string16(key_system) << ": "
+           << " [" << base::string16(session_id) << "]";
+
+  std::string ascii_key_system =
+      GetUnprefixedKeySystemName(ToASCIIOrEmpty(key_system));
+  std::string ascii_session_id = ToASCIIOrEmpty(session_id);
+
+  WebMediaPlayer::MediaKeyException e =
+      CancelKeyRequestInternal(ascii_key_system, ascii_session_id);
+  ReportMediaKeyExceptionToUMA("cancelKeyRequest", ascii_key_system, e);
+  return e;
+}
+
+WebMediaPlayer::MediaKeyException
+EncryptedMediaSupportImpl::CancelKeyRequestInternal(
+    const std::string& key_system,
+    const std::string& session_id) {
+  if (!IsConcreteSupportedKeySystem(key_system))
+    return WebMediaPlayer::MediaKeyExceptionKeySystemNotSupported;
+
+  if (current_key_system_.empty() || key_system != current_key_system_)
+    return WebMediaPlayer::MediaKeyExceptionInvalidPlayerState;
+
+  proxy_decryptor_->CancelKeyRequest(session_id);
+  return WebMediaPlayer::MediaKeyExceptionNoError;
+}
+
+void EncryptedMediaSupportImpl::setContentDecryptionModule(
+    blink::WebContentDecryptionModule* cdm) {
+  // TODO(xhwang): Support setMediaKeys(0) if necessary: http://crbug.com/330324
+  if (!cdm)
+    return;
+
+  web_cdm_ = ToWebContentDecryptionModuleImpl(cdm);
+
+  if (web_cdm_ && !decryptor_ready_cb_.is_null())
+    base::ResetAndReturn(&decryptor_ready_cb_)
+        .Run(web_cdm_->GetDecryptor(), base::Bind(DoNothing));
+}
+
+void EncryptedMediaSupportImpl::setContentDecryptionModule(
+    blink::WebContentDecryptionModule* cdm,
+    blink::WebContentDecryptionModuleResult result) {
+  // TODO(xhwang): Support setMediaKeys(0) if necessary: http://crbug.com/330324
+  if (!cdm) {
+    result.completeWithError(
+        blink::WebContentDecryptionModuleExceptionNotSupportedError,
+        0,
+        "Null MediaKeys object is not supported.");
+    return;
+  }
+
+  web_cdm_ = ToWebContentDecryptionModuleImpl(cdm);
+
+  if (web_cdm_ && !decryptor_ready_cb_.is_null()) {
+    base::ResetAndReturn(&decryptor_ready_cb_)
+        .Run(web_cdm_->GetDecryptor(),
+             BIND_TO_RENDER_LOOP1(
+                 &EncryptedMediaSupportImpl::ContentDecryptionModuleAttached,
+                 result));
+  } else {
+    // No pipeline/decoder connected, so resolve the promise. When something
+    // is connected, setting the CDM will happen in SetDecryptorReadyCB().
+    ContentDecryptionModuleAttached(result, true);
+  }
+}
+
+void EncryptedMediaSupportImpl::setContentDecryptionModuleSync(
+    blink::WebContentDecryptionModule* cdm) {
+  // Used when loading media and no pipeline/decoder attached yet.
+  DCHECK(decryptor_ready_cb_.is_null());
+
+  web_cdm_ = ToWebContentDecryptionModuleImpl(cdm);
+}
+
+void EncryptedMediaSupportImpl::ContentDecryptionModuleAttached(
+    blink::WebContentDecryptionModuleResult result,
+    bool success) {
+  if (success) {
+    result.complete();
+    return;
+  }
+
+  result.completeWithError(
+      blink::WebContentDecryptionModuleExceptionNotSupportedError,
+      0,
+      "Unable to set MediaKeys object");
+}
+
+media::SetDecryptorReadyCB
+EncryptedMediaSupportImpl::CreateSetDecryptorReadyCB() {
+  return BIND_TO_RENDER_LOOP(&EncryptedMediaSupportImpl::SetDecryptorReadyCB);
+}
+
+media::Demuxer::NeedKeyCB
+EncryptedMediaSupportImpl::CreateNeedKeyCB() {
+  return BIND_TO_RENDER_LOOP(&EncryptedMediaSupportImpl::OnNeedKey);
+}
+
+void EncryptedMediaSupportImpl::OnDecryptError() {
+  EmeUMAHistogramCounts(current_key_system_, "DecryptError", 1);
+}
+
+void EncryptedMediaSupportImpl::OnNeedKey(const std::string& type,
+                                   const std::vector<uint8>& init_data) {
+  // Do not fire NeedKey event if encrypted media is not enabled.
+  if (!blink::WebRuntimeFeatures::isPrefixedEncryptedMediaEnabled() &&
+      !blink::WebRuntimeFeatures::isEncryptedMediaEnabled()) {
+    return;
+  }
+
+  UMA_HISTOGRAM_COUNTS(kMediaEme + std::string("NeedKey"), 1);
+
+  DCHECK(init_data_type_.empty() || type.empty() || type == init_data_type_);
+  if (init_data_type_.empty())
+    init_data_type_ = type;
+
+  const uint8* init_data_ptr = init_data.empty() ? NULL : &init_data[0];
+  client_->keyNeeded(
+      WebString::fromUTF8(type), init_data_ptr, init_data.size());
+}
+
+void EncryptedMediaSupportImpl::OnKeyAdded(const std::string& session_id) {
+  EmeUMAHistogramCounts(current_key_system_, "KeyAdded", 1);
+  client_->keyAdded(
+      WebString::fromUTF8(GetPrefixedKeySystemName(current_key_system_)),
+      WebString::fromUTF8(session_id));
+}
+
+void EncryptedMediaSupportImpl::OnKeyError(const std::string& session_id,
+                                    media::MediaKeys::KeyError error_code,
+                                    uint32 system_code) {
+  EmeUMAHistogramEnumeration(current_key_system_, "KeyError",
+                             error_code, media::MediaKeys::kMaxKeyError);
+
+  uint16 short_system_code = 0;
+  if (system_code > std::numeric_limits<uint16>::max()) {
+    LOG(WARNING) << "system_code exceeds unsigned short limit.";
+    short_system_code = std::numeric_limits<uint16>::max();
+  } else {
+    short_system_code = static_cast<uint16>(system_code);
+  }
+
+  client_->keyError(
+      WebString::fromUTF8(GetPrefixedKeySystemName(current_key_system_)),
+      WebString::fromUTF8(session_id),
+      static_cast<WebMediaPlayerClient::MediaKeyErrorCode>(error_code),
+      short_system_code);
+}
+
+void EncryptedMediaSupportImpl::OnKeyMessage(const std::string& session_id,
+                                      const std::vector<uint8>& message,
+                                      const GURL& destination_url) {
+  DCHECK(destination_url.is_empty() || destination_url.is_valid());
+
+  client_->keyMessage(
+      WebString::fromUTF8(GetPrefixedKeySystemName(current_key_system_)),
+      WebString::fromUTF8(session_id),
+      message.empty() ? NULL : &message[0],
+      message.size(),
+      destination_url);
+}
+
+void EncryptedMediaSupportImpl::SetDecryptorReadyCB(
+     const media::DecryptorReadyCB& decryptor_ready_cb) {
+  // Cancels the previous decryptor request.
+  if (decryptor_ready_cb.is_null()) {
+    if (!decryptor_ready_cb_.is_null()) {
+      base::ResetAndReturn(&decryptor_ready_cb_)
+          .Run(NULL, base::Bind(DoNothing));
+    }
+    return;
+  }
+
+  // TODO(xhwang): Support multiple decryptor notification request (e.g. from
+  // video and audio). The current implementation is okay for the current
+  // media pipeline since we initialize audio and video decoders in sequence.
+  // But WebMediaPlayerImpl should not depend on media pipeline's implementation
+  // detail.
+  DCHECK(decryptor_ready_cb_.is_null());
+
+  // Mixed use of prefixed and unprefixed EME APIs is disallowed by Blink.
+  DCHECK(!proxy_decryptor_ || !web_cdm_);
+
+  if (proxy_decryptor_) {
+    decryptor_ready_cb.Run(proxy_decryptor_->GetDecryptor(),
+                           base::Bind(DoNothing));
+    return;
+  }
+
+  if (web_cdm_) {
+    decryptor_ready_cb.Run(web_cdm_->GetDecryptor(), base::Bind(DoNothing));
+    return;
+  }
+
+  decryptor_ready_cb_ = decryptor_ready_cb;
+}
+
+}  // namespace content