Issue #276 - introduce class BSTR_Argument

src/plugin/PluginFilter.cpp

Index: src/plugin/PluginFilter.cpp
===================================================================
--- a/src/plugin/PluginFilter.cpp
+++ b/src/plugin/PluginFilter.cpp
@@ -2,6 +2,7 @@
 
 #include "PluginFilter.h"
 
+#include "COM_Value.h"
 #if (defined PRODUCT_ADBLOCKPLUS)
 #include "PluginSettings.h"
 #include "PluginClient.h"
@@ -16,7 +17,6 @@
 
 #include "..\shared\CriticalSection.h"
 
-
 // The filters are described at http://adblockplus.org/en/filters
 
 static CriticalSection s_criticalSectionFilterMap;
@@ -25,7 +25,7 @@
 // CFilterElementHideAttrSelector
 // ============================================================================
 
-CFilterElementHideAttrSelector::CFilterElementHideAttrSelector() : m_type(TYPE_NONE), m_pos(POS_NONE), m_bstrAttr(NULL)
+CFilterElementHideAttrSelector::CFilterElementHideAttrSelector() : m_type(TYPE_NONE), m_pos(POS_NONE)
 {
 }
 
@@ -33,7 +33,7 @@
 {
   m_type = filter.m_type;
   m_pos = filter.m_pos;
-  m_bstrAttr = filter.m_bstrAttr;
+  m_attr = filter.m_attr;
 
   m_value = filter.m_value;
 }
@@ -150,26 +150,26 @@
 
       if (arg.GetAt(delimiterPos - 1) == '^')
       {
-        attrSelector.m_bstrAttr = arg.Left(delimiterPos - 1);
+        attrSelector.m_attr = arg.Left(delimiterPos - 1);
         attrSelector.m_pos = CFilterElementHideAttrPos::STARTING;
       }
       else if (arg.GetAt(delimiterPos - 1) == '*')
       {
-        attrSelector.m_bstrAttr = arg.Left(delimiterPos - 1);
+        attrSelector.m_attr = arg.Left(delimiterPos - 1);
         attrSelector.m_pos = CFilterElementHideAttrPos::ANYWHERE;
       }
       else if (arg.GetAt(delimiterPos - 1) == '$')
       {
-        attrSelector.m_bstrAttr = arg.Left(delimiterPos - 1);
+        attrSelector.m_attr = arg.Left(delimiterPos - 1);
         attrSelector.m_pos = CFilterElementHideAttrPos::ENDING;
       }
       else
       {
-        attrSelector.m_bstrAttr = arg.Left(delimiterPos);
+        attrSelector.m_attr = arg.Left(delimiterPos);
         attrSelector.m_pos = CFilterElementHideAttrPos::EXACT;
       }
     }
-    CString tag = attrSelector.m_bstrAttr;
+    CString tag = attrSelector.m_attr;
     if (tag == "style")
     {
       attrSelector.m_type = CFilterElementHideAttrType::STYLE;
@@ -242,20 +242,20 @@
 
   if (!m_tagId.IsEmpty())
   {
-    CComBSTR id;
+    AdblockPlus::COM::BSTR_Argument id;
     hr = pEl->get_id(&id);
-    if ((hr != S_OK) || (id != CComBSTR(m_tagId)))
+    if ((hr != S_OK) || (to_CString(id) != m_tagId))
     {
       return false;
     }
   }
   if (!m_tagClassName.IsEmpty())
   {
-    CComBSTR classNameBSTR;
-    hr = pEl->get_className(&classNameBSTR);
+    AdblockPlus::COM::BSTR_Argument result;
+    hr = pEl->get_className(&result);
     if (hr == S_OK)
     {
-      CString className = classNameBSTR;
+      CString className = to_CString(result);
       int start = 0;
       CString specificClass;
       bool foundMatch = false;
@@ -275,10 +275,11 @@
   }
   if (!m_tag.IsEmpty())
   {
-    CComBSTR tagName;
-    tagName.ToLower();
-    hr = pEl->get_tagName(&tagName);
-    if ((hr != S_OK) || (tagName != CComBSTR(m_tag)))
+    AdblockPlus::COM::BSTR_Argument result;
+    hr = pEl->get_tagName(&result);
+    CString tagName = to_CString(result);
+    tagName.MakeLower();
+    if ((hr != S_OK) || tagName != m_tag)
     {
       return false;
     }
@@ -295,38 +296,48 @@
       CComPtr<IHTMLStyle> pStyle;
       if (SUCCEEDED(pEl->get_style(&pStyle)) && pStyle)
       {
-        CComBSTR bstrStyle;
-
-        if (SUCCEEDED(pStyle->get_cssText(&bstrStyle)) && bstrStyle)
+        AdblockPlus::COM::BSTR_Argument cssText;
+        if (SUCCEEDED(pStyle->get_cssText(&cssText)))
         {
-          value = bstrStyle;
-          value.MakeLower();
-          attrFound = true;
+          value = to_CString(cssText);
+          if (!value.IsEmpty())
+          {
+            value.MakeLower();
+            attrFound = true;
+          }
         }
       }
     }
     else if (attrIt->m_type == CFilterElementHideAttrType::CLASS)
     {
-      CComBSTR bstrClassNames;
-      if (SUCCEEDED(pEl->get_className(&bstrClassNames)) && bstrClassNames)
+      AdblockPlus::COM::BSTR_Argument classNames;
+      if (SUCCEEDED(pEl->get_className(&classNames)))
       {
-        value = bstrClassNames;
-        attrFound = true;
+        value = to_CString(classNames);
+        if (!value.IsEmpty())
+        {
+          attrFound = true;
+        }
       }
     }
     else if (attrIt->m_type == CFilterElementHideAttrType::ID)
     {
-      CComBSTR bstrId;
-      if (SUCCEEDED(pEl->get_id(&bstrId)) && bstrId)
+      AdblockPlus::COM::BSTR_Argument id;
+      if (SUCCEEDED(pEl->get_id(&id)))
       {
-        value = bstrId;
-        attrFound = true;
+        value = to_CString(id);
+        if (!value.IsEmpty())
+        {
+          attrFound = true;
+        }
       }
     }
     else 
     {
       CComVariant vAttr;
-      if (SUCCEEDED(pEl->getAttribute(attrIt->m_bstrAttr, 0, &vAttr)))
+      CString attr = attrIt->m_attr;  // temporary required because to_wstring conversion cannot be const.
+      AdblockPlus::COM::BSTR_Argument attribute_name(to_wstring(attr));
+      if (SUCCEEDED(pEl->getAttribute(attribute_name, 0, &vAttr)))
       {
         attrFound = true;
         if (vAttr.vt == VT_BSTR)
@@ -507,17 +518,17 @@
 bool CPluginFilter::IsElementHidden(const CString& tag, IHTMLElement* pEl, const CString& domain, const CString& indent) const
 {
   CString id;
-  CComBSTR bstrId;
-  if (SUCCEEDED(pEl->get_id(&bstrId)) && bstrId)
+  AdblockPlus::COM::BSTR_Argument result;
+  if (SUCCEEDED(pEl->get_id(&result)))
   {
-    id = bstrId;
+    id = to_CString(result);
   }
 
   CString classNames;
-  CComBSTR bstrClassNames;
-  if (SUCCEEDED(pEl->get_className(&bstrClassNames)) && bstrClassNames)
+  // reuse of 'result' is not an error, since address-of operator permits it
+  if (SUCCEEDED(pEl->get_className(&result)))
   {
-    classNames = bstrClassNames;
+    classNames = to_CString(result);
   }
 
   CriticalSection::Lock filterEngineLock(s_criticalSectionFilterMap);