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

compiled/ElemHideBase.cpp

+#include <emscripten/bind.h>
+
+#include "ElemHideBase.h"
+#include "ElemHideFilter.h"
+#include "ElemHideException.h"
+
+namespace
+{
+  class Scanner
+  {
+  private:
+    const std::wstring& str;
+    size_t pos;
+    size_t end;
+  public:
+    Scanner(const std::wstring& str) : str(str), pos(0), end(str.length()) {}
+
+    bool done()
+    {
+      return pos >= end;
+    }
+
+    size_t position()
+    {
+      return pos - 1;
+    }
+
+    wchar_t next()
+    {
+      return done() ? L'\0' : str[pos++];
+    }
+  };
+}
+
+ElemHideBase::ElemHideBase(const std::wstring& text, size_t domainsEnd,
+    size_t selectorStart)
+    : ActiveFilter(text)
+{
+}
+
+Filter::Type ElemHideBase::Parse(const std::wstring& text, size_t* domainsEnd,
+    size_t* selectorStart)
+{
+  Scanner scanner(text);
+
+  // Domains part
+  loop:
+  while (!scanner.done())
+  {
+    wchar_t next = scanner.next();
+    if (next == L'#')
+    {
+      *domainsEnd = scanner.position();
+      break;
+    }
+
+    switch (next)
+    {
+      case L'/':
+      case L'*':
+      case L'|':
+      case L'@':
+      case L'"':
+      case L'!':
+        return Type::UNKNOWN;
+    }
+  }
+
+  bool exception = false;
+  wchar_t next = scanner.next();
+  if (next == L'@')
+  {
+    exception = true;
+    next = scanner.next();
+  }
+
+  if (next != L'#')
+    return Type::UNKNOWN;
+
+  // Selector part
+
+  // Selector shouldn't be empty
+  if (scanner.done())
+    return Type::UNKNOWN;
+
+  *selectorStart = scanner.position() + 1;
+  while (!scanner.done())
+  {
+    switch (scanner.next())
+    {
+      case L'{':
+      case L'}':
+        return Type::UNKNOWN;
+    }
+  }
+
+  return exception ? Type::ELEMHIDEEXCEPTION : Type::ELEMHIDE;
+}
+
+ElemHideBase* ElemHideBase::Create(const std::wstring& text)
+{
+  size_t domainsEnd;
+  size_t selectorStart;
+  Type type = Parse(text, &domainsEnd, &selectorStart);
+  if (type == Type::UNKNOWN)
+    return nullptr;
+  else if (type == Type::ELEMHIDEEXCEPTION)
+    return new ElemHideException(text, domainsEnd, selectorStart);
+  else
+    return new ElemHideFilter(text, domainsEnd, selectorStart);
+}
+
+EMSCRIPTEN_BINDINGS(elemhidebase)
+{
+  using namespace emscripten;
+  class_<ElemHideBase,base<ActiveFilter>>("ElemHideBase");
+}