Issue 5146 - Implement DownloadableSubscription parsing in C++

compiled/subscription/DownloadableSubscription.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <cwctype>
+
 #include "DownloadableSubscription.h"
+#include "../FilterNotifier.h"
+#include "../StringScanner.h"
+#include "../filter/CommentFilter.h"
+
+namespace {
+  constexpr int MILLIS_IN_HOUR = 60 * 60 * 1000;
+  constexpr int MILLIS_IN_DAY = 24 * MILLIS_IN_HOUR;
+}
+
+_DownloadableSubscription_Parser::_DownloadableSubscription_Parser(DownloadableSubscription& sub)
+    : mSubscription(&sub)
+{
+}
+
+void _DownloadableSubscription_Parser::Process(DependentString& line)
+{
+  auto filter = FilterPtr(Filter::FromText(line), false);
+  if (filter->mType == Filter::Type::COMMENT)
+  {
+    auto comment = filter->As<CommentFilter>();
+    if (!comment->GetParam().empty())
+    {
+      if (comment->GetParam() == u"checksum"_str)
+      {
+        // XXX we'll have to calculate the checksum.

[hub, 2017/11/13 22:35:27]

this part will require import a md5sum calculation function from somewhere.

But TODO before for the final patch.

+      }
+      mParams[comment->GetParam()] = comment->GetValue();
+    }
+  }
+
+  if (filter)
+    mFilters.push_back(filter);
+}
+
+int _DownloadableSubscription_Parser::ParseExpires(const String& expires)
+{
+  bool isHour = false;
+  StringScanner scanner(expires);
+  String::size_type numStart = 0;
+  String::size_type numLen = 0;
+  while(!scanner.done())
+  {
+    auto ch = scanner.next();
+    if (std::iswdigit(ch))
+    {
+      if (numLen == 0)
+        numStart = scanner.position();
+      numLen++;
+    }
+    else if (std::iswspace(ch))
+    {
+      if (numLen)
+        break;
+    }
+    else
+    {
+      if (numLen)
+        scanner.back();
+      break;
+    }
+  }
+
+  DependentString numStr(expires, numStart, numLen);
+  int num = numStr.toInt();
+  if (num == 0)
+    return 0;
+
+  while (!scanner.done())
+  {
+    auto ch = scanner.next();
+    if (std::iswspace(ch))
+      continue;
+    if (ch == u'h')
+    {
+      isHour = true;
+      // assume we are done here. The rest is ignored.
+      break;
+    }
+  }
+  // check for overflow.
+  if (!isHour && num > 24)

[hub, 2017/11/13 22:35:27]

I should check the overflow for the expiration in hours as well. And make this
"24" a const. (basically 2^31 / (24 * 3600 * 1000) rounded down).

There is note about not using 64-bits integer.

+    return 0;
+
+  num *= isHour ? MILLIS_IN_HOUR : MILLIS_IN_DAY;
+  return num;
+}
+
+int _DownloadableSubscription_Parser::Finalize()
+{
+  auto entry = mParams.find(u"title"_str);
+  if (entry)
+  {
+    mSubscription->SetTitle(entry->second);
+    mSubscription->SetFixedTitle(true);
+  }
+  else
+    mSubscription->SetFixedTitle(false);
+
+  int version = 0;
+  entry = mParams.find(u"version"_str);
+  if (entry)
+    version = entry->second.toInt();
+  mSubscription->SetDataRevision(version);
+
+  int expires = 0;
+  entry = mParams.find(u"expires"_str);
+  if (entry)
+    expires = ParseExpires(entry->second);
+
+  FilterNotifier::SubscriptionChange(
+    FilterNotifier::Topic::SUBSCRIPTION_BEFORE_FILTERS_REPLACED,
+    *mSubscription);

[hub, 2017/11/13 22:35:28]

I'm not if that's the right place to send this notification.

+  auto oldFilters = std::move(mSubscription->GetFilters());
+  mSubscription->GetFilters() = std::move(mFilters);
+  FilterNotifier::SubscriptionChange(
+    FilterNotifier::Topic::SUBSCRIPTION_FILTERS_REPLACED, *mSubscription);
+
+  return expires;
+}
+
+namespace {
+  DependentString emptyString = u""_str;
+}
+
+const String& _DownloadableSubscription_Parser::GetRedirect() const
+{
+  auto entry = mParams.find(u"redirect"_str);
+  if (entry)
+    return entry->second;
+  return emptyString;
+}
+
+const String& _DownloadableSubscription_Parser::GetHomepage() const
+{
+  auto entry = mParams.find(u"homepage"_str);
+  if (entry)
+    return entry->second;
+  return emptyString;
+}
 
 DownloadableSubscription::DownloadableSubscription(const String& id)
     : Subscription(classType, id), mFixedTitle(false), mLastCheck(0),
       mHardExpiration(0), mSoftExpiration(0), mLastDownload(0), mLastSuccess(0),
       mErrorCount(0), mDataRevision(0), mDownloadCount(0)
 {
   SetTitle(id);
 }
 
+_DownloadableSubscription_Parser* DownloadableSubscription::ParseDownload()
+{
+  return new _DownloadableSubscription_Parser(*this);
+}
+
 OwnedString DownloadableSubscription::Serialize() const
 {
   OwnedString result(Subscription::Serialize());
   if (mFixedTitle)
     result.append(u"fixedTitle=true\n"_str);
   if (!mHomepage.empty())
   {
     result.append(u"homepage="_str);
     result.append(mHomepage);
     result.append(u'\n');
@@ skipping 53 matching lines @@
     result.append(u'\n');
   }
   if (mDownloadCount)
   {
     result.append(u"downloadCount="_str);
     result.append(mDownloadCount);
     result.append(u'\n');
   }
   return result;
 }