Issue 4125 - [emscripten] Convert filter classes to C++

compiled/RegExpFilter.cpp

+#include <climits>
+
+#include <emscripten.h>
+
+#include "RegExpFilter.h"
+#include "StringScanner.h"
+#include "StringMap.h"
+
+namespace
+{
+  enum
+  {
+    TYPE_OTHER = 0x1,
+    TYPE_SCRIPT = 0x2,
+    TYPE_IMAGE = 0x4,
+    TYPE_STYLESHEET = 0x8,
+    TYPE_OBJECT = 0x10,
+    TYPE_SUBDOCUMENT = 0x20,
+    TYPE_DOCUMENT = 0x40,
+    TYPE_PING = 0x400,
+    TYPE_XMLHTTPREQUEST = 0x800,
+    TYPE_OBJECT_SUBREQUEST = 0x1000,
+    TYPE_MEDIA = 0x4000,
+    TYPE_FONT = 0x8000,
+    TYPE_POPUP = 0x8000000,
+    TYPE_GENERICBLOCK = 0x10000000,
+    TYPE_GENERICHIDE = 0x20000000,
+    TYPE_ELEMHIDE = 0x40000000,
+  };
+
+  StringMap<int> typeMap {
+    {u"other"_str, TYPE_OTHER},
+    {u"script"_str, TYPE_SCRIPT},
+    {u"image"_str, TYPE_IMAGE},
+    {u"stylesheet"_str, TYPE_STYLESHEET},
+    {u"object"_str, TYPE_OBJECT},
+    {u"subdocument"_str, TYPE_SUBDOCUMENT},
+    {u"document"_str, TYPE_DOCUMENT},
+    {u"xbl"_str, TYPE_OTHER},          // Backwards compat
+    {u"ping"_str, TYPE_PING},
+    {u"xmlhttprequest"_str, TYPE_XMLHTTPREQUEST},
+    {u"object-subrequest"_str, TYPE_OBJECT_SUBREQUEST},
+    {u"dtd"_str, TYPE_OTHER},          // Backwards compat
+    {u"media"_str, TYPE_MEDIA},
+    {u"font"_str, TYPE_FONT},
+    {u"background"_str, TYPE_IMAGE},   // Backwards compat
+
+    {u"popup"_str, TYPE_POPUP},
+    {u"genericblock"_str, TYPE_GENERICBLOCK},
+    {u"generichide"_str, TYPE_GENERICHIDE},
+    {u"elemhide"_str, TYPE_ELEMHIDE},
+  };
+
+  const int defaultTypeMask = INT_MAX & ~(TYPE_DOCUMENT | TYPE_ELEMHIDE |
+      TYPE_POPUP | TYPE_GENERICBLOCK | TYPE_GENERICHIDE);
+
+  int GenerateRegExp(const String& regexp, bool matchCase)
+  {
+    return EM_ASM_INT(return regexps.create($0, $1), &regexp, matchCase);
+  }
+
+  void NormalizeWhitespace(DependentString& text)
+  {
+    // We want to remove all spaces but bail out early in the common scenario
+    // that the string contains no spaces.
+
+    // Look for the first space
+    String::size_type len = text.length();
+    String::size_type pos;
+    for (pos = 0; pos < len; pos++)
+      if (text[pos] == ' ')
+        break;
+
+    if (pos >= len)
+      return;
+
+    // Found spaces, move characters to remove them
+    String::size_type delta = 1;
+    for (pos = pos + 1; pos < len; pos++)
+    {
+      if (text[pos] == ' ')
+        delta++;
+      else
+        text[pos - delta] = text[pos];
+    }
+    text.reset(text, 0, len - delta);
+  }
+
+  void ParseOption(String& text, DependentString& error, RegExpFilterData& data,
+      int optionStart, int optionEnd, int valueStart, int valueEnd)
+  {
+    if (optionEnd <= optionStart)
+      return;
+
+    bool reverse = false;
+    if (text[optionStart] == u'~')
+    {
+      reverse = true;
+      optionStart++;
+    }
+
+    DependentString name(text, optionStart, optionEnd - optionStart);
+    for (size_t i = 0; i < name.length(); ++i)
+    {
+      char16_t currChar = name[i];
+      if (currChar >= u'A' && currChar <= u'Z')
+        name[i] = currChar + u'a' - u'A';
+      else if (currChar == u'_')
+        name[i] = u'-';
+    }
+
+    auto it = typeMap.find(name);
+    if (it)
+    {
+      if (data.mContentType < 0)
+        data.mContentType = reverse ? defaultTypeMask : 0;
+      if (reverse)
+        data.mContentType &= ~it->second;
+      else
+        data.mContentType |= it->second;
+    }
+    else if (name.equals(u"domain"_str))
+    {
+      if (valueStart >= 0 && valueEnd > valueStart)
+      {
+        data.mDomainsStart = valueStart;
+        data.mDomainsEnd = valueEnd;
+        DependentString(text, valueStart, valueEnd - valueStart).toLower();
+      }
+    }
+    else if (name.equals(u"sitekey"_str))
+    {
+      if (valueStart >= 0 && valueEnd > valueStart)
+      {
+        data.mSitekeysStart = valueStart;
+        data.mSitekeysEnd = valueEnd;
+      }
+    }
+    else if (name.equals(u"match-case"_str))
+      data.mMatchCase = !reverse;
+    else if (name.equals(u"third-party"_str))
+      data.mThirdParty = reverse ? TrippleState::NO : TrippleState::YES;
+    else if (name.equals(u"collapse"_str))
+      data.mCollapse = reverse ? TrippleState::NO : TrippleState::YES;
+    else
+      error.reset(u"filter_unknown_option"_str);
+  }
+
+  void ParseOptions(String& text, DependentString& error, RegExpFilterData& data,
+      String::size_type optionsStart)
+  {
+    data.mMatchCase = false;
+    data.mThirdParty = TrippleState::ANY;
+    data.mCollapse = TrippleState::ANY;
+    data.mDomainsStart = String::npos;
+    data.mSitekeysStart = String::npos;
+    if (optionsStart >= text.length())
+    {
+      data.mContentType = defaultTypeMask;
+      return;
+    }
+
+    data.mContentType = -1;
+
+    int optionStart = data.mPatternEnd + 1;
+    int optionEnd = -1;
+    int valueStart = -1;
+
+    StringScanner scanner(text, optionStart, u',');
+    bool done = false;
+    while (!done)
+    {
+      done = scanner.done();
+      switch (scanner.next())
+      {
+        case u'=':
+          if (optionEnd < 0)
+          {
+            optionEnd = scanner.position();
+            valueStart = optionEnd + 1;
+          }
+          break;
+        case u',':
+          if (optionEnd < 0)
+            optionEnd = scanner.position();
+          ParseOption(text, error, data, optionStart, optionEnd, valueStart,
+              scanner.position());
+          if (!error.empty())
+            return;
+
+          optionStart = scanner.position() + 1;
+          optionEnd = -1;
+          valueStart = -1;
+          break;
+      }
+    }
+
+    if (data.mContentType < 0)
+      data.mContentType = defaultTypeMask;
+  }
+}
+
+RegExpFilter::RegExpFilter(Type type, const String& text, const RegExpFilterData& data)
+    : ActiveFilter(type, text, true), mData(data)
+{
+}
+
+RegExpFilter::~RegExpFilter()
+{
+  if (mData.HasRegExp())
+    EM_ASM_ARGS(regexps.delete($0), mData.mRegexpId);
+}
+
+Filter::Type RegExpFilter::Parse(DependentString& text, DependentString& error,
+    RegExpFilterData& data)
+{
+  NormalizeWhitespace(text);
+
+  Filter::Type type = Type::BLOCKING;
+
+  data.mPatternStart = 0;
+  if (text.length() >= 2 && text[0] == u'@' && text[1] == u'@')
+  {
+    type = Type::WHITELIST;
+    data.mPatternStart = 2;
+  }
+
+  data.mPatternEnd = text.find(u'$', data.mPatternStart);
+  if (data.mPatternEnd == text.npos)
+    data.mPatternEnd = text.length();
+
+  ParseOptions(text, error, data, data.mPatternEnd + 1);
+  if (!error.empty())
+    return Type::INVALID;
+
+  if (data.mPatternEnd - data.mPatternStart >= 2 &&
+      text[data.mPatternStart] == u'/' &&
+      text[data.mPatternEnd - 1] == u'/')
+  {
+    data.SetRegExp(GenerateRegExp(DependentString(text, data.mPatternStart + 1,
+        data.mPatternEnd - data.mPatternStart - 2), data.mMatchCase));
+    if (data.mRegexpId == -1)
+    {
+      error.reset(u"filter_invalid_regexp"_str);
+      return Type::INVALID;
+    }
+  }
+
+  return type;
+}
+
+void RegExpFilter::ParseSitekeys(const String& sitekeys) const
+{
+  StringScanner scanner(sitekeys, 0, u'|');
+  size_t start = 0;
+  bool done = false;
+  while (!done)
+  {
+    done = scanner.done();
+    if (scanner.next() == u'|')
+    {
+      if (scanner.position() > start)
+        AddSitekey(DependentString(sitekeys, start, scanner.position() - start));
+      start = scanner.position() + 1;
+    }
+  }
+}
+
+void RegExpFilter::InitJSTypes()
+{
+  EM_ASM(exports.RegExpFilter.typeMap = {};);
+  for (auto it = typeMap.begin(); it != typeMap.end(); ++it)
+    EM_ASM_ARGS(exports.RegExpFilter.typeMap[readString($0).replace("-", "_").toUpperCase()] = $1, &(it->first), it->second);
+}
+
+OwnedString RegExpFilter::RegExpFromSource(const String& source)
+{
+  /* TODO: this is very inefficient */
+
+  // Note: This doesn't remove trailing wildcards, otherwise the result should
+  // be identical to Filter.toRegExp().
+  OwnedString result;
+  String::value_type prevChar = u'*';
+  for (String::size_type i = 0; i < source.length(); ++i)
+  {
+    String::value_type currChar = source[i];
+    switch (currChar)
+    {
+      case u'*':
+        if (prevChar != u'*')
+          result.append(u".*"_str);
+        break;
+      case u'^':
+        result.append(u"(?:[\\x00-\\x24\\x26-\\x2C\\x2F\\x3A-\\x40\\x5B-\\x5E\\x60\\x7B-\\x7F]|$)"_str);
+        break;
+      case u'|':
+        if (i == 0)
+        {
+          // Anchor at expression start, maybe extended anchor?
+          if (i + 1 < source.length() && source[i + 1] == u'|')
+          {
+            result.append(u"^[\\w\\-]+:\\/+(?!\\/)(?:[^\\/]+\\.)?"_str);
+            ++i;
+          }
+          else
+            result.append(u'^');
+        }
+        else if (i == source.length() - 1)
+        {
+          // Anchor at expression end, ignore if following separator placeholder
+          if (prevChar != u'^')
+            result.append(u'$');
+        }
+        else
+        {
+          // Not actually an anchor, escape it
+          result.append(u"\\|"_str);
+        }
+        break;
+      default:
+        if (!(currChar >= u'a' && currChar <= u'z') &&
+            !(currChar >= u'A' && currChar <= u'Z') &&
+            !(currChar >= u'0' && currChar <= u'9') &&
+            currChar < 128)
+        {
+          result.append(u'\\');
+        }
+        result.append(currChar);
+    }
+    prevChar = currChar;
+  }
+  return result;
+}
+
+RegExpFilter::DomainMap* RegExpFilter::GetDomains() const
+{
+  if (!mData.DomainsParsingDone())
+  {
+    ParseDomains(mData.GetDomainsSource(mText), u'|');
+    mData.SetDomainsParsingDone();
+  }
+  return ActiveFilter::GetDomains();
+}
+
+RegExpFilter::SitekeySet* RegExpFilter::GetSitekeys() const
+{
+  if (!mData.SitekeyParsingDone())
+  {
+    ParseSitekeys(mData.GetSitekeysSource(mText));
+    mData.SetSitekeysParsingDone();
+  }
+  return ActiveFilter::GetSitekeys();
+}
+
+bool RegExpFilter::Matches(const String& location, int typeMask,
+    DependentString& docDomain, bool thirdParty, const String& sitekey) const
+{
+  if (!(mData.mContentType & typeMask) ||
+      (mData.mThirdParty == TrippleState::YES && !thirdParty) ||
+      (mData.mThirdParty == TrippleState::NO && thirdParty) ||
+      !IsActiveOnDomain(docDomain, sitekey))
+  {
+    return false;
+  }
+
+  if (!mData.RegExpParsingDone())
+  {
+    const OwnedString pattern(mData.GetRegExpSource(mText));
+    mData.SetRegExp(GenerateRegExp(RegExpFromSource(pattern), mData.mMatchCase));
+  }
+  return EM_ASM_INT(return regexps.test($0, $1), mData.mRegexpId, &location);
+}