tor-browser

AsyncUrlChannelClassifier.cpp (28863B)

---

/* -*- 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 "HttpBaseChannel.h"
#include "mozilla/Components.h"
#include "mozilla/ErrorNames.h"
#include "mozilla/net/AsyncUrlChannelClassifier.h"
#include "mozilla/dom/BrowsingContext.h"
#include "mozilla/dom/CanonicalBrowsingContext.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 "nsIUrlClassifierExceptionList.h"
#include "nsNetCID.h"
#include "nsNetUtil.h"
#include "nsPrintfCString.h"
#include "nsProxyRelease.h"
#include "nsServiceManagerUtils.h"
#include "nsUrlClassifierDBService.h"
#include "nsUrlClassifierUtils.h"
#include "mozilla/net/UrlClassifierCommon.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()) {
   if (mURIType == nsIUrlClassifierFeature::pairwiseEntitylistURI) {
     LookupCache::GetLookupEntitylistFragments(mURISpec, &mFragments);
   } else {
     LookupCache::GetLookupFragments(mURISpec, &mFragments);
   }
 }

 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);
   (void)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;

 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;

 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
 nsCOMPtr<nsIUrlClassifierExceptionList> exceptionList;
 nsresult rv = mFeature->GetExceptionList(getter_AddRefs(exceptionList));
 if (NS_WARN_IF(NS_FAILED(rv))) {
   UC_LOG_WARN(
       ("AsyncChannelClassifier::FeatureData::MaybeCompleteClassification - "
        "error while getting exception list. Let's move on [exceptionList=%p "
        "this=%p channel=%p]",
        exceptionList.get(), this, aChannel));
   return true;
 }

 // Check if current load is allow-listed by the exception list.
 if (!mBlocklistTables.IsEmpty() && exceptionList) {
   // Get top level URI from channel.
   nsCOMPtr<nsIURI> topLevelURI;
   rv = UrlClassifierCommon::GetTopWindowURI(aChannel,
                                             getter_AddRefs(topLevelURI));
   NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Failed to get top level URI");

   bool isPrivateBrowsing = NS_UsePrivateBrowsing(aChannel);
   bool isAllowListed = false;
   rv = exceptionList->Matches(mBlocklistTables[0]->URI(), topLevelURI,
                               isPrivateBrowsing, &isAllowListed);
   if (NS_SUCCEEDED(rv) && isAllowListed) {
     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);
 (void)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 */
void AsyncUrlChannelClassifier::WarmUp() {
 // Trigger the construction of the singleton instance.
 nsresult rv;
 RefPtr<nsUrlClassifierDBService> service =
     nsUrlClassifierDBService::GetInstance(&rv);
}

/* 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;
     (void)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;
 }

 // raise the priority of URLClassifier's return dispatch to the MainThread if
 // the channel is considered important
 EventQueuePriority eventPriority = EventQueuePriority::Normal;
 if (nsCOMPtr<HttpBaseChannel> baseChannel = do_QueryInterface(aChannel)) {
   uint32_t classOfServiceFlags = 0;
   baseChannel->GetClassFlags(&classOfServiceFlags);
   if (classOfServiceFlags &
       (nsIClassOfService::Leader | nsIClassOfService::UrgentStart |
        nsIClassOfService::Unblocked)) {
     eventPriority = EventQueuePriority::MediumHigh;
   }
 }
 if (nsCOMPtr<nsISupportsPriority> supportsPriority =
         do_QueryInterface(aChannel)) {
   int32_t priority = nsISupportsPriority::PRIORITY_NORMAL;
   supportsPriority->GetPriority(&priority);
   // note that higher priorities have lower numeric values
   if (priority <= nsISupportsPriority::PRIORITY_HIGH) {
     eventPriority = EventQueuePriority::MediumHigh;
   }
 }

 nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
     "AsyncUrlChannelClassifier::CheckChannel",
     [task, workerClassifier, eventPriority]() -> void {
       MOZ_ASSERT(!NS_IsMainThread());
       task->DoLookup(workerClassifier);

       NS_DispatchToMainThreadQueue(
           NS_NewRunnableFunction(
               "AsyncUrlChannelClassifier::CheckChannel - return",
               [task]() -> void { task->CompleteClassification(); }),
           eventPriority);
     });

 // no need to prioritize the dispatch to the URLClassifier thread
 // since overriding prioritization is ignored if we aren't on the MainThread
 return nsUrlClassifierDBService::BackgroundThread()->Dispatch(
     r, NS_DISPATCH_NORMAL);
}

}  // namespace net
}  // namespace mozilla