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

compiled/Filter.cpp

Index: compiled/Filter.cpp
===================================================================
new file mode 100644
--- /dev/null
+++ b/compiled/Filter.cpp
@@ -0,0 +1,118 @@
+#include <emscripten.h>
+#include <unordered_map>
+
+#include "Filter.h"
+#include "CommentFilter.h"
+#include "RegExpFilter.h"
+#include "ElemHideFilter.h"
+#include "ElemHideException.h"
+#include "tools.h"
+
+Filter::Filter(const std::u16string& text)
+{
+  this->text = text;
+}
+
+const std::u16string Filter::Serialize()
+{
+  return (
+    u"[Filter]\n"
+    u"text=" + text + u"\n"
+  );
+}
+
+namespace
+{
+  std::unordered_map<std::u16string,Filter*> knownFilters;
+
+  void trim_spaces(std::u16string& str)
+  {
+    size_t pos;
+
+    // Remove leading whitespace
+    pos = str.find_first_not_of(u' ');
+    if (pos > 0)
+      str.erase(0, pos);
+
+    // Remove trailing whitespace
+    pos = str.find_last_not_of(u' ');
+    if (pos < str.length() - 1)
+      str.erase(pos + 1);
+  }
+
+  void remove_spaces(std::u16string& str)
+  {
+    for (size_t i = 0, l = str.length(); i < l; ++i)
+    {
+      if (str[i] == u' ')
+      {
+        str.erase(i, 1);
+        --i;
+        --l;
+      }
+    }
+  }
+}
+
+extern "C"
+{
+  Filter* EMSCRIPTEN_KEEPALIVE Filter_FromText(char16_t* textPtr, int textLen)
+  {
+    std::u16string text(textPtr, textLen);
+    auto it = knownFilters.find(text);
+    if (it != knownFilters.end())
+      return it->second;
+
+    Filter* filter = CommentFilter::Create(text);
+    if (!filter)
+      filter = ElemHideBase::Create(text);
+    if (!filter)
+      filter = RegExpFilter::Create(text);
+    return knownFilters[text] = filter;
+  }
+  char16_t* EMSCRIPTEN_KEEPALIVE Filter_Normalize(char16_t* textPtr, size_t textLen, size_t* resultLen)
+  {
+    std::u16string text(textPtr, textLen);
+
+    // Remove special characters like line breaks
+    for (size_t i = 0, l = text.length(); i < l; ++i)
+    {
+      if (text[i] < u' ')
+      {
+        text.erase(i, 1);
+        --i;
+        --l;
+      }
+    }
+
+    trim_spaces(text);
+
+    {
+      size_t domainsEnd;
+      size_t selectorStart;
+      Filter::Type type = ElemHideBase::Parse(text, &domainsEnd, &selectorStart);
+      if (type != Filter::Type::UNKNOWN)
+      {
+        std::u16string domains = text.substr(0, domainsEnd);
+        std::u16string selector = text.substr(selectorStart);
+        remove_spaces(domains);
+        trim_spaces(selector);
+        return stringToBuffer(domains + (type == Filter::Type::ELEMHIDEEXCEPTION ? u"#@#" : u"##") + selector, resultLen);
+      }
+    }
+
+    if (CommentFilter::Parse(text) == Filter::Type::UNKNOWN)
+      remove_spaces(text);
+    return stringToBuffer(text, resultLen);
+  }
+
+  Filter::Type EMSCRIPTEN_KEEPALIVE Filter_get_type(Filter* filter)
+  {
+    return filter->GetType();
+  }
+
+  char16_t* EMSCRIPTEN_KEEPALIVE Filter_Serialize(Filter* filter, size_t* resultLen)
+  {
+    return stringToBuffer(filter->Serialize(), resultLen);
+  }
+}