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

compiled/ElemHideBase.cpp

+#include "ElemHideBase.h"
+#include "ElemHideFilter.h"
+#include "ElemHideException.h"
+#include "tools.h"
+
+class Scanner
+{
+private:
+  const std::u16string& str;
+  size_t pos;
+  size_t end;
+public:
+  Scanner(const std::u16string& str) : str(str), pos(0), end(str.length()) {}
+
+  bool done()
+  {
+    return pos >= end;
+  }
+
+  size_t position()
+  {
+    return pos - 1;
+  }
+
+  char16_t next()
+  {
+    return done() ? u'\0' : str[pos++];
+  }
+};
+
+ElemHideBase::ElemHideBase(const std::u16string& text, size_t domainsEnd, size_t selectorStart)
+    : ActiveFilter(text)
+{
+}
+
+Filter::Type ElemHideBase::Parse(const std::u16string& text, size_t* domainsEnd, size_t* selectorStart)
+{
+  Scanner scanner(text);
+
+  // Domains part
+  loop:
+  while (!scanner.done())
+  {
+    char16_t next = scanner.next();
+    if (next == u'#')
+    {
+      *domainsEnd = scanner.position();
+      break;
+    }
+
+    switch (next)
+    {
+      case u'/':
+      case u'*':
+      case u'|':
+      case u'@':
+      case u'"':
+      case u'!':
+        return Type::UNKNOWN;
+    }
+  }
+
+  bool exception = false;
+  char16_t next = scanner.next();
+  if (next == u'@')
+  {
+    exception = true;
+    next = scanner.next();
+  }
+
+  if (next != u'#')
+    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 u'{':
+      case u'}':
+        return Type::UNKNOWN;
+    }
+  }
+
+  return exception ? Type::ELEMHIDEEXCEPTION : Type::ELEMHIDE;
+}
+
+ElemHideBase* ElemHideBase::Create(const std::u16string& 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);
+}