Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 920 insertions, 0 deletions

diff --git a/netwerk/url-classifier/AsyncUrlChannelClassifier.cpp b/netwerk/url-classifier/AsyncUrlChannelClassifier.cpp
new file mode 100644
index 0000000000..4dfb7224e7
--- /dev/null
+++ b/netwerk/url-classifier/AsyncUrlChannelClassifier.cpp
@@ -0,0 +1,920 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set expandtab ts=4 sw=2 sts=2 cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Classifier.h"
+#include "mozilla/Components.h"
+#include "mozilla/ErrorNames.h"
+#include "mozilla/net/AsyncUrlChannelClassifier.h"
+#include "mozilla/net/UrlClassifierCommon.h"
+#include "mozilla/net/UrlClassifierFeatureFactory.h"
+#include "mozilla/net/UrlClassifierFeatureResult.h"
+#include "nsContentUtils.h"
+#include "nsIChannel.h"
+#include "nsIHttpChannel.h"
+#include "nsNetCID.h"
+#include "nsNetUtil.h"
+#include "nsPrintfCString.h"
+#include "nsProxyRelease.h"
+#include "nsServiceManagerUtils.h"
+#include "nsUrlClassifierDBService.h"
+#include "nsUrlClassifierUtils.h"
+
+namespace mozilla {
+namespace net {
+
+namespace {
+
+// Big picture comment
+// -----------------------------------------------------------------------------
+// nsUrlClassifierDBService::channelClassify() classifies a channel using a set
+// of URL-Classifier features. This method minimizes the number of lookups and
+// URI parsing and this is done using the classes here described.
+//
+// The first class is 'FeatureTask' which is able to retrieve the list of
+// features for this channel using the feature-factory. See
+// UrlClassifierFeatureFactory.
+// For each feature, it creates a FeatureData object, which contains the
+// entitylist and blocklist prefs and tables. The reason why we create
+// FeatureData is because:
+// - features are not thread-safe.
+// - we want to store the state of the classification in the FeatureData
+//   object.
+//
+// It can happen that multiple features share the same tables. In order to do
+// the lookup just once, we have TableData class. When multiple features
+// contain the same table, they have references to the same couple TableData +
+// URIData objects.
+//
+// During the classification, the channel's URIs are fragmented. In order to
+// create these fragments just once, we use the URIData class, which is pointed
+// by TableData classes.
+//
+// The creation of these classes happens on the main-thread. The classification
+// happens on the worker thread.
+
+// URIData
+// -----------------------------------------------------------------------------
+
+// In order to avoid multiple URI parsing, we have this class which contains
+// nsIURI and its fragments.
+class URIData {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(URIData);
+
+  static nsresult Create(nsIURI* aURI, nsIURI* aInnermostURI,
+                         nsIUrlClassifierFeature::URIType aURIType,
+                         URIData** aData);
+
+  bool IsEqual(nsIURI* aURI) const;
+
+  const nsTArray<nsCString>& Fragments();
+
+  nsIURI* URI() const;
+
+ private:
+  URIData();
+  ~URIData() = default;
+
+  nsCOMPtr<nsIURI> mURI;
+  nsCString mURISpec;
+  nsTArray<nsCString> mFragments;
+  nsIUrlClassifierFeature::URIType mURIType;
+};
+
+/* static */
+nsresult URIData::Create(nsIURI* aURI, nsIURI* aInnermostURI,
+                         nsIUrlClassifierFeature::URIType aURIType,
+                         URIData** aData) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aURI);
+  MOZ_ASSERT(aInnermostURI);
+
+  RefPtr<URIData> data = new URIData();
+  data->mURI = aURI;
+  data->mURIType = aURIType;
+
+  nsUrlClassifierUtils* utilsService = nsUrlClassifierUtils::GetInstance();
+  if (NS_WARN_IF(!utilsService)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = utilsService->GetKeyForURI(aInnermostURI, data->mURISpec);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::URIData::Create new URIData created for spec "
+       "%s [this=%p]",
+       data->mURISpec.get(), data.get()));
+
+  data.forget(aData);
+  return NS_OK;
+}
+
+URIData::URIData() { MOZ_ASSERT(NS_IsMainThread()); }
+
+bool URIData::IsEqual(nsIURI* aURI) const {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aURI);
+
+  bool isEqual = false;
+  nsresult rv = mURI->Equals(aURI, &isEqual);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  return isEqual;
+}
+
+const nsTArray<nsCString>& URIData::Fragments() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  if (mFragments.IsEmpty()) {
+    nsresult rv;
+
+    if (mURIType == nsIUrlClassifierFeature::pairwiseEntitylistURI) {
+      rv = LookupCache::GetLookupEntitylistFragments(mURISpec, &mFragments);
+    } else {
+      rv = LookupCache::GetLookupFragments(mURISpec, &mFragments);
+    }
+
+    Unused << NS_WARN_IF(NS_FAILED(rv));
+  }
+
+  return mFragments;
+}
+
+nsIURI* URIData::URI() const {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mURI;
+}
+
+// TableData
+// ----------------------------------------------------------------------------
+
+// In order to avoid multiple lookups on the same table + URI, we have this
+// class.
+class TableData {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TableData);
+
+  enum State {
+    eUnclassified,
+    eNoMatch,
+    eMatch,
+  };
+
+  TableData(URIData* aURIData, const nsACString& aTable);
+
+  nsIURI* URI() const;
+
+  const nsACString& Table() const;
+
+  const LookupResultArray& Result() const;
+
+  State MatchState() const;
+
+  bool IsEqual(URIData* aURIData, const nsACString& aTable) const;
+
+  // Returns true if the table classifies the URI. This method must be called
+  // on hte classifier worker thread.
+  bool DoLookup(nsUrlClassifierDBServiceWorker* aWorkerClassifier);
+
+ private:
+  ~TableData();
+
+  RefPtr<URIData> mURIData;
+  State mState;
+
+  nsCString mTable;
+  LookupResultArray mResults;
+};
+
+TableData::TableData(URIData* aURIData, const nsACString& aTable)
+    : mURIData(aURIData), mState(eUnclassified), mTable(aTable) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aURIData);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::TableData CTOR - new TableData created %s "
+       "[this=%p]",
+       aTable.BeginReading(), this));
+}
+
+TableData::~TableData() = default;
+
+nsIURI* TableData::URI() const {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mURIData->URI();
+}
+
+const nsACString& TableData::Table() const {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mTable;
+}
+
+const LookupResultArray& TableData::Result() const {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mResults;
+}
+
+TableData::State TableData::MatchState() const {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mState;
+}
+
+bool TableData::IsEqual(URIData* aURIData, const nsACString& aTable) const {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mURIData == aURIData && mTable == aTable;
+}
+
+bool TableData::DoLookup(nsUrlClassifierDBServiceWorker* aWorkerClassifier) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aWorkerClassifier);
+
+  if (mState == TableData::eUnclassified) {
+    UC_LOG_LEAK(
+        ("AsyncChannelClassifier::TableData::DoLookup - starting lookup "
+         "[this=%p]",
+         this));
+
+    const nsTArray<nsCString>& fragments = mURIData->Fragments();
+    nsresult rv = aWorkerClassifier->DoSingleLocalLookupWithURIFragments(
+        fragments, mTable, mResults);
+    Unused << NS_WARN_IF(NS_FAILED(rv));
+
+    mState = mResults.IsEmpty() ? TableData::eNoMatch : TableData::eMatch;
+
+    UC_LOG_LEAK(
+        ("AsyncChannelClassifier::TableData::DoLookup - lookup completed. "
+         "Matches: %d [this=%p]",
+         (int)mResults.Length(), this));
+  }
+
+  return !mResults.IsEmpty();
+}
+
+// FeatureData
+// ----------------------------------------------------------------------------
+
+class FeatureTask;
+
+// This is class contains all the Feature data.
+class FeatureData {
+  enum State {
+    eUnclassified,
+    eNoMatch,
+    eMatchBlocklist,
+    eMatchEntitylist,
+  };
+
+ public:
+  FeatureData() = default;
+  ~FeatureData();
+
+  nsresult Initialize(FeatureTask* aTask, nsIChannel* aChannel,
+                      nsIUrlClassifierFeature* aFeature);
+
+  void DoLookup(nsUrlClassifierDBServiceWorker* aWorkerClassifier);
+
+  // Returns true if the next feature should be processed.
+  bool MaybeCompleteClassification(nsIChannel* aChannel);
+
+ private:
+  nsresult InitializeList(FeatureTask* aTask, nsIChannel* aChannel,
+                          nsIUrlClassifierFeature::listType aListType,
+                          nsTArray<RefPtr<TableData>>& aList);
+
+  State mState{eUnclassified};
+  nsCOMPtr<nsIUrlClassifierFeature> mFeature;
+  nsCOMPtr<nsIChannel> mChannel;
+
+  nsTArray<RefPtr<TableData>> mBlocklistTables;
+  nsTArray<RefPtr<TableData>> mEntitylistTables;
+
+  // blocklist + entitylist.
+  nsCString mHostInPrefTables[2];
+};
+
+FeatureData::~FeatureData() {
+  NS_ReleaseOnMainThread("FeatureData:mFeature", mFeature.forget());
+}
+
+nsresult FeatureData::Initialize(FeatureTask* aTask, nsIChannel* aChannel,
+                                 nsIUrlClassifierFeature* aFeature) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aTask);
+  MOZ_ASSERT(aChannel);
+  MOZ_ASSERT(aFeature);
+
+  if (UC_LOG_ENABLED()) {
+    nsAutoCString name;
+    aFeature->GetName(name);
+    UC_LOG_LEAK(
+        ("AsyncChannelClassifier::FeatureData::Initialize - Feature %s "
+         "[this=%p, channel=%p]",
+         name.get(), this, aChannel));
+  }
+
+  mFeature = aFeature;
+  mChannel = aChannel;
+
+  nsresult rv = InitializeList(
+      aTask, aChannel, nsIUrlClassifierFeature::blocklist, mBlocklistTables);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = InitializeList(aTask, aChannel, nsIUrlClassifierFeature::entitylist,
+                      mEntitylistTables);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+void FeatureData::DoLookup(nsUrlClassifierDBServiceWorker* aWorkerClassifier) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aWorkerClassifier);
+  MOZ_ASSERT(mState == eUnclassified);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureData::DoLookup - lookup starting "
+       "[this=%p]",
+       this));
+
+  // This is wrong, but it's fast: we don't want to check if the host is in the
+  // blocklist table if we know that it's going to be entitylisted by pref.
+  // So, also if maybe it's not blocklisted, let's consider it 'entitylisted'.
+  if (!mHostInPrefTables[nsIUrlClassifierFeature::entitylist].IsEmpty()) {
+    UC_LOG_LEAK(
+        ("AsyncChannelClassifier::FeatureData::DoLookup - entitylisted by pref "
+         "[this=%p]",
+         this));
+    mState = eMatchEntitylist;
+    return;
+  }
+
+  // Let's check if this feature blocklists the URI.
+
+  bool isBlocklisted =
+      !mHostInPrefTables[nsIUrlClassifierFeature::blocklist].IsEmpty();
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureData::DoLookup - blocklisted by pref: "
+       "%d [this=%p]",
+       isBlocklisted, this));
+
+  if (!isBlocklisted) {
+    // If one of the blocklist table matches the URI, we don't need to continue
+    // with the others: the feature is blocklisted (but maybe also
+    // entitylisted).
+    for (TableData* tableData : mBlocklistTables) {
+      if (tableData->DoLookup(aWorkerClassifier)) {
+        isBlocklisted = true;
+        break;
+      }
+    }
+  }
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureData::DoLookup - blocklisted before "
+       "entitylisting: %d [this=%p]",
+       isBlocklisted, this));
+
+  if (!isBlocklisted) {
+    mState = eNoMatch;
+    return;
+  }
+
+  // Now, let's check if we need to entitylist the same URI.
+
+  for (TableData* tableData : mEntitylistTables) {
+    // If one of the entitylist table matches the URI, we don't need to continue
+    // with the others: the feature is entitylisted.
+    if (tableData->DoLookup(aWorkerClassifier)) {
+      UC_LOG_LEAK(
+          ("AsyncChannelClassifier::FeatureData::DoLookup - entitylisted by "
+           "table [this=%p]",
+           this));
+      mState = eMatchEntitylist;
+      return;
+    }
+  }
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureData::DoLookup - blocklisted [this=%p]",
+       this));
+  mState = eMatchBlocklist;
+}
+
+bool FeatureData::MaybeCompleteClassification(nsIChannel* aChannel) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsAutoCString name;
+  mFeature->GetName(name);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureData::MaybeCompleteClassification - "
+       "completing "
+       "classification [this=%p channel=%p]",
+       this, aChannel));
+
+  switch (mState) {
+    case eNoMatch:
+      UC_LOG(
+          ("AsyncChannelClassifier::FeatureData::MaybeCompleteClassification - "
+           "no match for feature %s. Let's "
+           "move on [this=%p channel=%p]",
+           name.get(), this, aChannel));
+      return true;
+
+    case eMatchEntitylist:
+      UC_LOG(
+          ("AsyncChannelClassifier::FeatureData::MayebeCompleteClassification "
+           "- entitylisted by feature %s. Let's "
+           "move on [this=%p channel=%p]",
+           name.get(), this, aChannel));
+      return true;
+
+    case eMatchBlocklist:
+      UC_LOG(
+          ("AsyncChannelClassifier::FeatureData::MaybeCompleteClassification - "
+           "blocklisted by feature %s [this=%p channel=%p]",
+           name.get(), this, aChannel));
+      break;
+
+    case eUnclassified:
+      MOZ_CRASH("We should not be here!");
+      break;
+  }
+
+  MOZ_ASSERT(mState == eMatchBlocklist);
+
+  // Maybe we have to ignore this host
+  nsAutoCString exceptionList;
+  nsresult rv = mFeature->GetExceptionHostList(exceptionList);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    UC_LOG_WARN(
+        ("AsyncChannelClassifier::FeatureData::MayebeCompleteClassification - "
+         "error. Let's move on [this=%p channel=%p]",
+         this, aChannel));
+    return true;
+  }
+
+  if (!mBlocklistTables.IsEmpty() &&
+      nsContentUtils::IsURIInList(mBlocklistTables[0]->URI(), exceptionList)) {
+    nsCString spec = mBlocklistTables[0]->URI()->GetSpecOrDefault();
+    spec.Truncate(std::min(spec.Length(), UrlClassifierCommon::sMaxSpecLength));
+    UC_LOG(
+        ("AsyncChannelClassifier::FeatureData::MaybeCompleteClassification - "
+         "uri %s found in "
+         "exceptionlist of feature %s [this=%p channel=%p]",
+         spec.get(), name.get(), this, aChannel));
+    return true;
+  }
+
+  nsTArray<nsCString> list;
+  nsTArray<nsCString> hashes;
+  if (!mHostInPrefTables[nsIUrlClassifierFeature::blocklist].IsEmpty()) {
+    list.AppendElement(mHostInPrefTables[nsIUrlClassifierFeature::blocklist]);
+
+    // Telemetry expects every tracking channel has hash, create it for test
+    // entry
+    Completion complete;
+    complete.FromPlaintext(
+        mHostInPrefTables[nsIUrlClassifierFeature::blocklist]);
+    hashes.AppendElement(complete.ToString());
+  }
+
+  for (TableData* tableData : mBlocklistTables) {
+    if (tableData->MatchState() == TableData::eMatch) {
+      list.AppendElement(tableData->Table());
+
+      for (const auto& r : tableData->Result()) {
+        hashes.AppendElement(r->hash.complete.ToString());
+      }
+    }
+  }
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureData::MaybeCompleteClassification - "
+       "process channel [this=%p channel=%p]",
+       this, aChannel));
+
+  bool shouldContinue = false;
+  rv = mFeature->ProcessChannel(aChannel, list, hashes, &shouldContinue);
+  Unused << NS_WARN_IF(NS_FAILED(rv));
+
+  return shouldContinue;
+}
+
+// CallbackHolder
+// ----------------------------------------------------------------------------
+
+// This class keeps the callback alive and makes sure that we release it on the
+// correct thread.
+class CallbackHolder final {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(CallbackHolder);
+
+  explicit CallbackHolder(std::function<void()>&& aCallback)
+      : mCallback(std::move(aCallback)) {}
+
+  void Exec() const { mCallback(); }
+
+ private:
+  ~CallbackHolder() = default;
+
+  std::function<void()> mCallback;
+};
+
+// FeatureTask
+// ----------------------------------------------------------------------------
+
+// A FeatureTask is a class that is able to classify a channel using a set of
+// features. The features are grouped by:
+// - URIs - to avoid extra URI parsing.
+// - Tables - to avoid multiple lookup on the same table.
+class FeatureTask {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(FeatureTask);
+
+  static nsresult Create(nsIChannel* aChannel,
+                         std::function<void()>&& aCallback,
+                         FeatureTask** aTask);
+
+  // Called on the classifier thread.
+  void DoLookup(nsUrlClassifierDBServiceWorker* aWorkerClassifier);
+
+  // Called on the main-thread to process the channel.
+  void CompleteClassification();
+
+  nsresult GetOrCreateURIData(nsIURI* aURI, nsIURI* aInnermostURI,
+                              nsIUrlClassifierFeature::URIType aURIType,
+                              URIData** aData);
+
+  nsresult GetOrCreateTableData(URIData* aURIData, const nsACString& aTable,
+                                TableData** aData);
+
+ private:
+  FeatureTask(nsIChannel* aChannel, std::function<void()>&& aCallback);
+  ~FeatureTask();
+
+  nsCOMPtr<nsIChannel> mChannel;
+  RefPtr<CallbackHolder> mCallbackHolder;
+
+  nsTArray<FeatureData> mFeatures;
+  nsTArray<RefPtr<URIData>> mURIs;
+  nsTArray<RefPtr<TableData>> mTables;
+};
+
+// Features are able to classify particular URIs from a channel. For instance,
+// tracking-annotation feature uses the top-level URI to entitylist the current
+// channel's URI.  Because of
+// this, this function aggregates feature per URI and tables.
+/* static */
+nsresult FeatureTask::Create(nsIChannel* aChannel,
+                             std::function<void()>&& aCallback,
+                             FeatureTask** aTask) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aChannel);
+  MOZ_ASSERT(aTask);
+
+  // We need to obtain the list of nsIUrlClassifierFeature objects able to
+  // classify this channel. If the list is empty, we do an early return.
+  nsTArray<nsCOMPtr<nsIUrlClassifierFeature>> features;
+  UrlClassifierFeatureFactory::GetFeaturesFromChannel(aChannel, features);
+  if (features.IsEmpty()) {
+    UC_LOG(
+        ("AsyncChannelClassifier::FeatureTask::Create - no task is needed for "
+         "channel %p",
+         aChannel));
+    return NS_OK;
+  }
+
+  RefPtr<FeatureTask> task = new FeatureTask(aChannel, std::move(aCallback));
+
+  UC_LOG(
+      ("AsyncChannelClassifier::FeatureTask::Create - FeatureTask %p created "
+       "for channel %p",
+       task.get(), aChannel));
+
+  for (nsIUrlClassifierFeature* feature : features) {
+    FeatureData* featureData = task->mFeatures.AppendElement();
+    nsresult rv = featureData->Initialize(task, aChannel, feature);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  task.forget(aTask);
+  return NS_OK;
+}
+
+FeatureTask::FeatureTask(nsIChannel* aChannel,
+                         std::function<void()>&& aCallback)
+    : mChannel(aChannel) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mChannel);
+
+  std::function<void()> callback = std::move(aCallback);
+  mCallbackHolder = new CallbackHolder(std::move(callback));
+}
+
+FeatureTask::~FeatureTask() {
+  NS_ReleaseOnMainThread("FeatureTask::mChannel", mChannel.forget());
+  NS_ReleaseOnMainThread("FeatureTask::mCallbackHolder",
+                         mCallbackHolder.forget());
+}
+
+nsresult FeatureTask::GetOrCreateURIData(
+    nsIURI* aURI, nsIURI* aInnermostURI,
+    nsIUrlClassifierFeature::URIType aURIType, URIData** aData) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aURI);
+  MOZ_ASSERT(aInnermostURI);
+  MOZ_ASSERT(aData);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureTask::GetOrCreateURIData - checking if "
+       "a URIData must be "
+       "created [this=%p]",
+       this));
+
+  for (URIData* data : mURIs) {
+    if (data->IsEqual(aURI)) {
+      UC_LOG_LEAK(
+          ("AsyncChannelClassifier::FeatureTask::GetOrCreateURIData - reuse "
+           "existing URIData %p [this=%p]",
+           data, this));
+
+      RefPtr<URIData> uriData = data;
+      uriData.forget(aData);
+      return NS_OK;
+    }
+  }
+
+  RefPtr<URIData> data;
+  nsresult rv =
+      URIData::Create(aURI, aInnermostURI, aURIType, getter_AddRefs(data));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  mURIs.AppendElement(data);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureTask::GetOrCreateURIData - create new "
+       "URIData %p [this=%p]",
+       data.get(), this));
+
+  data.forget(aData);
+  return NS_OK;
+}
+
+nsresult FeatureTask::GetOrCreateTableData(URIData* aURIData,
+                                           const nsACString& aTable,
+                                           TableData** aData) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aURIData);
+  MOZ_ASSERT(aData);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureTask::GetOrCreateTableData - checking "
+       "if TableData must be "
+       "created [this=%p]",
+       this));
+
+  for (TableData* data : mTables) {
+    if (data->IsEqual(aURIData, aTable)) {
+      UC_LOG_LEAK(
+          ("FeatureTask::GetOrCreateTableData - reuse existing TableData %p "
+           "[this=%p]",
+           data, this));
+
+      RefPtr<TableData> tableData = data;
+      tableData.forget(aData);
+      return NS_OK;
+    }
+  }
+
+  RefPtr<TableData> data = new TableData(aURIData, aTable);
+  mTables.AppendElement(data);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureTask::GetOrCreateTableData - create new "
+       "TableData %p [this=%p]",
+       data.get(), this));
+
+  data.forget(aData);
+  return NS_OK;
+}
+
+void FeatureTask::DoLookup(nsUrlClassifierDBServiceWorker* aWorkerClassifier) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aWorkerClassifier);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureTask::DoLookup - starting lookup "
+       "[this=%p]",
+       this));
+
+  for (FeatureData& feature : mFeatures) {
+    feature.DoLookup(aWorkerClassifier);
+  }
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureTask::DoLookup - lookup completed "
+       "[this=%p]",
+       this));
+}
+
+void FeatureTask::CompleteClassification() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  for (FeatureData& feature : mFeatures) {
+    if (!feature.MaybeCompleteClassification(mChannel)) {
+      break;
+    }
+  }
+
+  UC_LOG(
+      ("AsyncChannelClassifier::FeatureTask::CompleteClassification - complete "
+       "classification for "
+       "channel %p [this=%p]",
+       mChannel.get(), this));
+
+  mCallbackHolder->Exec();
+}
+
+nsresult FeatureData::InitializeList(
+    FeatureTask* aTask, nsIChannel* aChannel,
+    nsIUrlClassifierFeature::listType aListType,
+    nsTArray<RefPtr<TableData>>& aList) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aTask);
+  MOZ_ASSERT(aChannel);
+
+  UC_LOG_LEAK(
+      ("AsyncChannelClassifier::FeatureData::InitializeList - initialize list "
+       "%d for channel %p [this=%p]",
+       aListType, aChannel, this));
+
+  nsCOMPtr<nsIURI> uri;
+  nsIUrlClassifierFeature::URIType URIType;
+  nsresult rv = mFeature->GetURIByListType(aChannel, aListType, &URIType,
+                                           getter_AddRefs(uri));
+  if (NS_FAILED(rv)) {
+    if (UC_LOG_ENABLED()) {
+      nsAutoCString errorName;
+      GetErrorName(rv, errorName);
+      UC_LOG_LEAK(
+          ("AsyncChannelClassifier::FeatureData::InitializeList - Got an "
+           "unexpected error (rv=%s) [this=%p]",
+           errorName.get(), this));
+    }
+    return rv;
+  }
+
+  if (!uri) {
+    // Return success when the URI is empty to conitnue to do the lookup.
+    UC_LOG_LEAK(
+        ("AsyncChannelClassifier::FeatureData::InitializeList - got an empty "
+         "URL [this=%p]",
+         this));
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIURI> innermostURI = NS_GetInnermostURI(uri);
+  if (NS_WARN_IF(!innermostURI)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoCString host;
+  rv = innermostURI->GetHost(host);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  bool found = false;
+  nsAutoCString tableName;
+  rv = mFeature->HasHostInPreferences(host, aListType, tableName, &found);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (found) {
+    mHostInPrefTables[aListType] = tableName;
+  }
+
+  RefPtr<URIData> uriData;
+  rv = aTask->GetOrCreateURIData(uri, innermostURI, URIType,
+                                 getter_AddRefs(uriData));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  MOZ_ASSERT(uriData);
+
+  nsTArray<nsCString> tables;
+  rv = mFeature->GetTables(aListType, tables);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  for (const nsCString& table : tables) {
+    RefPtr<TableData> data;
+    rv = aTask->GetOrCreateTableData(uriData, table, getter_AddRefs(data));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    MOZ_ASSERT(data);
+    aList.AppendElement(data);
+  }
+
+  return NS_OK;
+}
+
+}  // namespace
+
+/* static */
+nsresult AsyncUrlChannelClassifier::CheckChannel(
+    nsIChannel* aChannel, std::function<void()>&& aCallback) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(aChannel);
+
+  if (!aCallback) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (UC_LOG_ENABLED()) {
+    nsCOMPtr<nsIURI> chanURI;
+    if (NS_SUCCEEDED(aChannel->GetURI(getter_AddRefs(chanURI)))) {
+      nsCString chanSpec = chanURI->GetSpecOrDefault();
+      chanSpec.Truncate(
+          std::min(chanSpec.Length(), UrlClassifierCommon::sMaxSpecLength));
+
+      nsCOMPtr<nsIURI> topWinURI;
+      Unused << UrlClassifierCommon::GetTopWindowURI(aChannel,
+                                                     getter_AddRefs(topWinURI));
+      nsCString topWinSpec =
+          topWinURI ? topWinURI->GetSpecOrDefault() : "(null)"_ns;
+
+      topWinSpec.Truncate(
+          std::min(topWinSpec.Length(), UrlClassifierCommon::sMaxSpecLength));
+
+      UC_LOG(
+          ("AsyncUrlChannelClassifier::CheckChannel - starting the "
+           "classification on channel %p",
+           aChannel));
+      UC_LOG(("    uri is %s [channel=%p]", chanSpec.get(), aChannel));
+      UC_LOG(
+          ("    top-level uri is %s [channel=%p]", topWinSpec.get(), aChannel));
+    }
+  }
+
+  RefPtr<FeatureTask> task;
+  nsresult rv =
+      FeatureTask::Create(aChannel, std::move(aCallback), getter_AddRefs(task));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (!task) {
+    // No task is needed for this channel, return an error so the caller won't
+    // wait for a callback.
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<nsUrlClassifierDBServiceWorker> workerClassifier =
+      nsUrlClassifierDBService::GetWorker();
+  if (NS_WARN_IF(!workerClassifier)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
+      "AsyncUrlChannelClassifier::CheckChannel",
+      [task, workerClassifier]() -> void {
+        MOZ_ASSERT(!NS_IsMainThread());
+        task->DoLookup(workerClassifier);
+
+        nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
+            "AsyncUrlChannelClassifier::CheckChannel - return",
+            [task]() -> void { task->CompleteClassification(); });
+
+        NS_DispatchToMainThread(r);
+      });
+
+  return nsUrlClassifierDBService::BackgroundThread()->Dispatch(
+      r, NS_DISPATCH_NORMAL);
+}
+
+}  // namespace net
+}  // namespace mozilla