Issues #1163, #1173 - refactor CPluginUserSettings

src/plugin/PluginUserSettings.cpp

 #include "PluginStdAfx.h"
 #include "PluginUserSettings.h"
 #include <algorithm>
 #include "PluginSettings.h"
 #include "PluginClient.h"
 #include "../shared/Dictionary.h"
-
-static const CString s_GetMessage = L"GetMessage";
-static const CString s_GetLanguageCount = L"GetLanguageCount";
-static const CString s_GetLanguageByIndex = L"GetLanguageByIndex";
-static const CString s_GetLanguageTitleByIndex = L"GetLanguageTitleByIndex";
-static const CString s_SetLanguage = L"SetLanguage";
-static const CString s_GetLanguage = L"GetLanguage";
-static const CString s_GetWhitelistDomains = L"GetWhitelistDomains";
-static const CString s_AddWhitelistDomain = L"AddWhitelistDomain";
-static const CString s_RemoveWhitelistDomain = L"RemoveWhitelistDomain";
-static const CString s_GetAppLocale = L"GetAppLocale";
-static const CString s_GetDocumentationLink = L"GetDocumentationLink";
-static const CString s_IsAcceptableAdsEnabled = L"IsAcceptableAdsEnabled";
-static const CString s_SetAcceptableAdsEnabled = L"SetAcceptableAdsEnabled";
-static const CString s_IsUpdate = L"IsUpdate";
-static const CString s_Methods[] = {s_GetMessage, s_GetLanguageCount, s_GetLanguageByIndex, s_GetLanguageTitleByIndex, s_SetLanguage, s_GetLanguage, s_GetWhitelistDomains, s_AddWhitelistDomain, s_RemoveWhitelistDomain, s_GetAppLocale, s_GetDocumentationLink, s_IsAcceptableAdsEnabled, s_SetAcceptableAdsEnabled, s_IsUpdate};
-
-CPluginUserSettings::CPluginUserSettings()
-{
-}
-
-
+#include <unordered_map>
+
+namespace
+{
+  enum UserSettingsMethods
+  {
+    dispatchID_GetMessage = 0,
+    dispatchID_GetLanguageCount,
+    dispatchID_GetLanguageByIndex,
+    dispatchID_GetLanguageTitleByIndex,
+    dispatchID_SetLanguage,
+    dispatchID_GetLanguage,
+    dispatchID_GetWhitelistDomains,
+    dispatchID_AddWhitelistDomain,
+    dispatchID_RemoveWhitelistDomain,
+    dispatchID_GetAppLocale,
+    dispatchID_GetDocumentationLink,
+    dispatchID_IsAcceptableAdsEnabled,
+    dispatchID_SetAcceptableAdsEnabled,
+    dispatchID_IsUpdate,
+  };
+
+  /**
+   * Auxiliary for static initialization
+   */
+  std::unordered_map<std::wstring, DISPID> InitMethodIndex()
+  {
+    std::unordered_map<std::wstring, DISPID> m;
+    // try-block for safety during static initialization
+    try
+    {
+      m.emplace(L"GetMessage", dispatchID_GetMessage);
+      m.emplace(L"GetLanguageCount", dispatchID_GetLanguageCount);
+      m.emplace(L"GetLanguageByIndex", dispatchID_GetLanguageByIndex);
+      m.emplace(L"GetLanguageTitleByIndex", dispatchID_GetLanguageTitleByIndex);
+      m.emplace(L"SetLanguage", dispatchID_SetLanguage);
+      m.emplace(L"GetLanguage", dispatchID_GetLanguage);
+      m.emplace(L"GetWhitelistDomains", dispatchID_GetWhitelistDomains);
+      m.emplace(L"AddWhitelistDomain", dispatchID_AddWhitelistDomain);
+      m.emplace(L"RemoveWhitelistDomain", dispatchID_RemoveWhitelistDomain);
+      m.emplace(L"GetAppLocale", dispatchID_GetAppLocale);
+      m.emplace(L"GetDocumentationLink", dispatchID_GetDocumentationLink);
+      m.emplace(L"IsAcceptableAdsEnabled", dispatchID_IsAcceptableAdsEnabled);
+      m.emplace(L"SetAcceptableAdsEnabled", dispatchID_SetAcceptableAdsEnabled);
+      m.emplace(L"IsUpdate", dispatchID_IsUpdate);
+    }
+    catch(...)
+    {
+    }
+    return m;
+  }
+
+  /**
+   * Static map from method names to dispatch identifiers.
+   */
+  std::unordered_map<std::wstring, DISPID> methodIndex = InitMethodIndex();
+}
+
+// ENTRY POINT
 STDMETHODIMP CPluginUserSettings::QueryInterface(REFIID riid, void **ppvObj)
 {
-  if (IID_IUnknown == riid  ||  IID_IDispatch == riid)
-  {
-    *ppvObj = (LPVOID)this;
-    return NOERROR;
-  }
-
+  if (!ppvObj)
+  {
+    return E_POINTER;
+  }
+  if (riid == IID_IUnknown || riid == IID_IDispatch) // GUID comparison does not throw
+  {
+    *ppvObj = static_cast<void *>(this);
+    return S_OK;
+  }
   return E_NOINTERFACE;
 }
 
-
-/*
-Since CPluginUserSettings is not allocated on the heap, 'AddRef' and 'Release' don't need reference counting,
-because CPluginUserSettings won't be deleted when reference counter == 0
-*/
-
+/**
+ * \par Limitation
+ *   CPluginUserSettings is not allocated on the heap.
+ *   It appears only as a member variable in CPluginTabBase.
+ *   'AddRef' and 'Release' don't need reference counting because they don't present COM factories.
+ */
 ULONG __stdcall CPluginUserSettings::AddRef()
 {
   return 1;
 }
 
-
 ULONG __stdcall CPluginUserSettings::Release()
 {
   return 1;
 }
 
-
 STDMETHODIMP CPluginUserSettings::GetTypeInfoCount(UINT* pctinfo)
 {
   return E_NOTIMPL;
 }
 
-
 STDMETHODIMP CPluginUserSettings::GetTypeInfo(UINT itinfo, LCID lcid, ITypeInfo** pptinfo)
 {
   return E_NOTIMPL;
 }
 
-
-STDMETHODIMP CPluginUserSettings::GetIDsOfNames(REFIID riid, LPOLESTR* rgszNames, UINT cNames, LCID lcid, DISPID* rgdispid)
-{
-  if (!rgszNames)
-    return E_POINTER;
-
-  if (!rgdispid)
-    return E_POINTER;
-
-  if (1 != cNames)
+/**
+ * \par Limitation
+ *   The specification for this method in IDispatch maps an array of names to an array of identifiers.
+ *   This version only supports single-element arrays, which is enough for IE's JavaScript interpreter.
+ */
+STDMETHODIMP CPluginUserSettings::GetIDsOfNames(REFIID, LPOLESTR* name, UINT count, LCID, DISPID* id)
+{
+  try
+  {
+    if (!name || !id)
+    {
+      return E_POINTER;
+    }
+    if (count != 1)
+    {
+      return E_FAIL;
+    }
+    auto item = methodIndex.find(*name); // unordered_map::find is not declared noexcept
+    if (item==methodIndex.end())
+    {
+      return DISP_E_UNKNOWNNAME;
+    }
+    *id = item->second;
+  }
+  catch (...)
+  {
     return E_FAIL;
-
-  size_t indxMethod = 0;
-  for (; indxMethod < countof(s_Methods); indxMethod++)
-  {
-    if (*rgszNames == s_Methods[indxMethod])
-      break;
-  }
-
-  if (indxMethod == countof(s_Methods))
-    return DISP_E_MEMBERNOTFOUND;
-
-  *rgdispid = static_cast<DISPID>(indxMethod);
-
+  }
   return S_OK;
 }
 
-
-static CString sGetLanguage()
-{
-  CPluginSettings* settings = CPluginSettings::GetInstance();
-  return settings->GetSubscription();
-}
-
-
 CStringW sGetMessage(const CString& section, const CString& key)
 {
   Dictionary* dictionary = Dictionary::GetInstance();
   return CStringW(dictionary->Lookup(std::string(CW2A(section)), std::string(CW2A(key))).c_str());
 }
 
-std::wstring sGetMessage(const std::string& section, const std::string& key)
-{
-  Dictionary* dictionary = Dictionary::GetInstance();
-  return dictionary->Lookup(section, key);
-}
-
-
 STDMETHODIMP CPluginUserSettings::Invoke(DISPID dispidMember, REFIID riid, LCID lcid, WORD wFlags, DISPPARAMS* pDispparams, VARIANT* pVarResult,
                                          EXCEPINFO* pExcepinfo, UINT* pArgErr)
 {
-  if (!pDispparams)
-    return E_POINTER;
-
-  if (!pExcepinfo)
-    return E_POINTER;
-
-  if (pDispparams->cNamedArgs)
-    return DISP_E_NONAMEDARGS;
-
-  CPluginSettings* settings = CPluginSettings::GetInstance();
-
-  if (dispidMember  < 0  ||  dispidMember >= countof(s_Methods))
-    return DISP_E_BADINDEX;
-
-  const CString& method = s_Methods[dispidMember];
-
-  if (s_GetMessage == method)
-  {
-    if (2 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (VT_BSTR != pDispparams->rgvarg[0].vt)
-      return DISP_E_TYPEMISMATCH;
-
-    if (pVarResult)
-    {
-      CComBSTR key = pDispparams->rgvarg[0].bstrVal;
-      CComBSTR section = pDispparams->rgvarg[1].bstrVal;
-      CStringW message = sGetMessage((BSTR)section, (BSTR)key);
-
-      pVarResult->vt = VT_BSTR;
-      pVarResult->bstrVal = SysAllocString(message);
-    }
-  }
-  else if (s_GetLanguageCount == method)
-  {
-    if (pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (pVarResult)
-    {
-      std::map<CString, CString> languageList = settings->GetFilterLanguageTitleList();
-
-      pVarResult->vt = VT_I4;
-      pVarResult->lVal = static_cast<LONG>(languageList.size());
-    }
-  }
-  else if (s_GetLanguageByIndex == method)
-  {
-    if (1 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (VT_I4 != pDispparams->rgvarg[0].vt)
-      return DISP_E_TYPEMISMATCH;
-
-    if (pVarResult)
-    {
-      int indx = pDispparams->rgvarg[0].lVal;
-
-      std::map<CString, CString> languageTitleList = settings->GetFilterLanguageTitleList();
-
-      if (indx < 0  ||  indx >= (int)languageTitleList.size())
-        return DISP_E_EXCEPTION;
-
-      CString language;
-
-      int curIndx = 0;
-      for(std::map<CString, CString>::const_iterator it = languageTitleList.begin(); it != languageTitleList.end(); ++it)
-      {
-        if (curIndx == indx)
-        {
-          language = it->first;
-          break;
-        }
-
-        curIndx++;
-      }
-
-      pVarResult->vt = VT_BSTR;
-      pVarResult->bstrVal = SysAllocString(language);
-    }
-  }
-  else if (s_GetLanguageTitleByIndex == method)
-  {
-    if (1 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (VT_I4 != pDispparams->rgvarg[0].vt)
-      return DISP_E_TYPEMISMATCH;
-
-    if (pVarResult)
-    {
-      int indx = pDispparams->rgvarg[0].lVal;
-
-      std::map<CString, CString> languageTitleList = settings->GetFilterLanguageTitleList();
-
-      if (indx < 0  ||  indx >= (int)languageTitleList.size())
-        return DISP_E_EXCEPTION;
-
-      CString languageTitle;
-
-      int curIndx = 0;
-      for(std::map<CString, CString>::const_iterator it = languageTitleList.begin(); it != languageTitleList.end(); ++it)
-      {
-        if (curIndx == indx)
-        {
-          languageTitle = it->second;
-          break;
-        }
-
-        curIndx++;
-      }
-
-      pVarResult->vt = VT_BSTR;
-      pVarResult->bstrVal = SysAllocString(languageTitle);
-    }
-  }
-  else if (s_SetLanguage == method)
-  {
-    if (1 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (VT_BSTR != pDispparams->rgvarg[0].vt)
-      return DISP_E_TYPEMISMATCH;
-
-    CComBSTR url = pDispparams->rgvarg[0].bstrVal;
-
-    settings->SetSubscription((BSTR)url);
-  }
-  else if (s_GetLanguage == method)
-  {
-    if (pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (pVarResult)
-    {
-      CString url = settings->GetSubscription();
-
-      pVarResult->vt = VT_BSTR;
-      pVarResult->bstrVal = SysAllocString(url);
-    }
-  }
-  else if (s_GetWhitelistDomains == method)
-  {
-    if (pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (pVarResult)
-    {
-      std::vector<std::wstring> whiteList = settings->GetWhiteListedDomainList();
-      CString sWhiteList;
-      for (size_t i = 0; i < whiteList.size(); i++)
-      {
-        if (!sWhiteList.IsEmpty())
-        {
-          sWhiteList += ',';
-        }
-        sWhiteList += CString(whiteList[i].c_str());
-      }
-
-      pVarResult->vt = VT_BSTR;
-      pVarResult->bstrVal = SysAllocString(sWhiteList);
-    }
-  }
-  else if (s_AddWhitelistDomain == method)
-  {
-    if (1 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (VT_BSTR != pDispparams->rgvarg[0].vt)
-      return DISP_E_TYPEMISMATCH;
-
-    CComBSTR domain = pDispparams->rgvarg[0].bstrVal;
-    if (domain.Length())
-    {
-      settings->AddWhiteListedDomain((BSTR)domain);
-    }
-  }
-  else if (s_RemoveWhitelistDomain == method)
-  {
-    if (1 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (VT_BSTR != pDispparams->rgvarg[0].vt)
-      return DISP_E_TYPEMISMATCH;
-
-    CComBSTR domain = pDispparams->rgvarg[0].bstrVal;
-    if (domain.Length())
-    {
-      settings->RemoveWhiteListedDomain((BSTR)domain);
-    }
-  }
-  else if (s_GetAppLocale == method)
-  {
-    if (0 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    pVarResult->vt = VT_BSTR;
-    pVarResult->bstrVal = SysAllocString(settings->GetAppLocale());
-  }
-  else if (s_GetDocumentationLink == method)
-  {
-    if (0 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    pVarResult->vt = VT_BSTR;
-    pVarResult->bstrVal = SysAllocString(settings->GetDocumentationLink());
-  }
-  else if (s_IsAcceptableAdsEnabled == method)
-  {
-    if (0 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    pVarResult->vt = VT_BOOL;
-    pVarResult->boolVal = CPluginClient::GetInstance()->IsAcceptableAdsEnabled() ? VARIANT_TRUE : VARIANT_FALSE;
-  }
-  else if (s_SetAcceptableAdsEnabled == method)
-  {
-    if (1 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    if (VT_BOOL != pDispparams->rgvarg[0].vt)
-      return DISP_E_TYPEMISMATCH;
-
-    bool enable = VARIANT_FALSE != pDispparams->rgvarg[0].boolVal;
-
-    if (enable)
-    {
-      CPluginClient* client = CPluginClient::GetInstance();
-      client->AddSubscription(client->GetPref(L"subscriptions_exceptionsurl", L""));
-    }
-    else
-    {
-      CPluginClient* client = CPluginClient::GetInstance();
-      client->RemoveSubscription(client->GetPref(L"subscriptions_exceptionsurl", L""));
-    }
-  }
-  else if (s_IsUpdate == method)
-  {
-    if (0 != pDispparams->cArgs)
-      return DISP_E_BADPARAMCOUNT;
-
-    pVarResult->vt = VT_BOOL;
-    pVarResult->boolVal = CPluginClient::GetInstance()->GetPref(L"displayUpdatePage", false);
-  }
-  else
-    return DISP_E_MEMBERNOTFOUND;
-
+  try
+  {
+    if (!pDispparams || !pExcepinfo)

[sergei, 2015/01/09 15:42:54]

pExcepinfo can be nullptr, it's not an error.

[Eric, 2015/01/09 16:25:24]

I'm mostly trying to add an exception handler in this function, but I don't mind
addressing a few small defects at the same time.

I just checked and we're not even referencing pExcepinfo, much less properly
using it for error conditions.

+    {
+      return E_POINTER;
+    }
+    if (pDispparams->cNamedArgs != 0)
+    {
+      return DISP_E_NONAMEDARGS;
+    }
+    CPluginSettings* settings = CPluginSettings::GetInstance();
+    switch (dispidMember)
+    {
+    case dispatchID_GetMessage:
+      {
+        if (pDispparams->cArgs != 2)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (pDispparams->rgvarg[0].vt != VT_BSTR || pDispparams->rgvarg[1].vt != VT_BSTR)
+        {
+          return DISP_E_TYPEMISMATCH;
+        }
+        if (pVarResult)

[sergei, 2015/01/09 15:42:54]

Wouldn't it better here and below to have
if (!pVarResult)
{
  return E_POINTER;
}
CComBSTR key = pDispparams->rgvarg[0].bstrVal;
...
BTW, sometimes there is even no test whether pVarResult is not nullptr.

[Eric, 2015/01/09 16:25:24]

No. It's not an error to ignore the return value. If pVarResult is null, there's
no way to return a value from the invoked method, and thus no point in executing
such a method unless it has side effects.

Apropos, see below for SetLanguage, which is executed solely for its side
effects and does not return a value.

We could use this snippet
    if (!pVarResult)
    {
      return S_OK;
    }
    // ...
if we want to remove a level of indentation for the code below it, but that's a
high degree of change that I'd prefer not do in the present change set.

[sergei, 2015/01/30 16:01:40]

What is about GetAppLocale and below? We should test whether `pVarResult` is not
nullptr.

[Eric, 2015/02/02 14:46:39]

Indeed, there were four defect where 'pVarResult' was not checked against
nullptr before dereferencing. Those are fixed in patch set 5.

For the record, those defects were not introduced in this refactoring, but we
shall take the opportunity to fix them while we're doing this one.

+        {
+          CComBSTR key = pDispparams->rgvarg[0].bstrVal;
+          CComBSTR section = pDispparams->rgvarg[1].bstrVal;
+          CStringW message = sGetMessage((BSTR)section, (BSTR)key);
+
+          pVarResult->vt = VT_BSTR;
+          pVarResult->bstrVal = SysAllocString(message);
+        }
+      }
+      break;
+    case dispatchID_GetLanguageCount:
+      {
+        if (pDispparams->cArgs != 0)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (pVarResult)
+        {
+          std::map<CString, CString> languageList = settings->GetFilterLanguageTitleList();
+
+          pVarResult->vt = VT_I4;
+          pVarResult->lVal = static_cast<LONG>(languageList.size());
+        }
+      }
+      break;
+    case dispatchID_GetLanguageByIndex:
+      {
+        if (pDispparams->cArgs != 1)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (VT_I4 != pDispparams->rgvarg[0].vt)
+        {
+          return DISP_E_TYPEMISMATCH;
+        }
+        if (pVarResult)
+        {
+          int indx = pDispparams->rgvarg[0].lVal;
+
+          std::map<CString, CString> languageTitleList = settings->GetFilterLanguageTitleList();
+
+          if (indx < 0  ||  indx >= (int)languageTitleList.size())
+            return DISP_E_EXCEPTION;
+
+          CString language;
+
+          int curIndx = 0;
+          for(std::map<CString, CString>::const_iterator it = languageTitleList.begin(); it != languageTitleList.end(); ++it)
+          {
+            if (curIndx == indx)
+            {
+              language = it->first;
+              break;
+            }
+            curIndx++;
+          }
+
+          pVarResult->vt = VT_BSTR;
+          pVarResult->bstrVal = SysAllocString(language);
+        }
+      }
+      break;
+    case dispatchID_GetLanguageTitleByIndex:
+      {
+        if (pDispparams->cArgs != 1)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (VT_I4 != pDispparams->rgvarg[0].vt)
+        {
+          return DISP_E_TYPEMISMATCH;
+        }
+        if (pVarResult)
+        {
+          int indx = pDispparams->rgvarg[0].lVal;
+
+          std::map<CString, CString> languageTitleList = settings->GetFilterLanguageTitleList();
+
+          if (indx < 0  ||  indx >= (int)languageTitleList.size())
+            return DISP_E_EXCEPTION;
+
+          CString languageTitle;
+
+          int curIndx = 0;
+          for(std::map<CString, CString>::const_iterator it = languageTitleList.begin(); it != languageTitleList.end(); ++it)
+          {
+            if (curIndx == indx)
+            {
+              languageTitle = it->second;
+              break;
+            }
+            curIndx++;
+          }
+
+          pVarResult->vt = VT_BSTR;
+          pVarResult->bstrVal = SysAllocString(languageTitle);
+        }
+      }
+      break;
+    case dispatchID_SetLanguage:
+      {
+        if (pDispparams->cArgs != 1)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (VT_BSTR != pDispparams->rgvarg[0].vt)
+        {
+          return DISP_E_TYPEMISMATCH;
+        }
+        CComBSTR url = pDispparams->rgvarg[0].bstrVal;
+        settings->SetSubscription((BSTR)url);
+      }
+      break;
+    case dispatchID_GetLanguage:
+      {
+        if (pDispparams->cArgs != 0)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (pVarResult)
+        {
+          CString url = settings->GetSubscription();
+          pVarResult->vt = VT_BSTR;
+          pVarResult->bstrVal = SysAllocString(url);
+        }
+      }
+      break;
+    case dispatchID_GetWhitelistDomains:
+      {
+        if (pDispparams->cArgs != 0)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (pVarResult)
+        {
+          std::vector<std::wstring> whiteList = settings->GetWhiteListedDomainList();
+          CString sWhiteList;
+          for (size_t i = 0; i < whiteList.size(); i++)
+          {
+            if (!sWhiteList.IsEmpty())
+            {
+              sWhiteList += ',';
+            }
+            sWhiteList += CString(whiteList[i].c_str());
+          }
+          pVarResult->vt = VT_BSTR;
+          pVarResult->bstrVal = SysAllocString(sWhiteList);
+        }
+      }
+      break;
+    case dispatchID_AddWhitelistDomain:
+      {
+        if (pDispparams->cArgs != 1)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (VT_BSTR != pDispparams->rgvarg[0].vt)
+        {
+          return DISP_E_TYPEMISMATCH;
+        }
+        CComBSTR domain = pDispparams->rgvarg[0].bstrVal;
+        if (domain.Length())
+        {
+          settings->AddWhiteListedDomain((BSTR)domain);
+        }
+      }
+      break;
+    case dispatchID_RemoveWhitelistDomain:
+      {
+        if (pDispparams->cArgs != 1)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (VT_BSTR != pDispparams->rgvarg[0].vt)
+        {
+          return DISP_E_TYPEMISMATCH;
+        }
+        CComBSTR domain = pDispparams->rgvarg[0].bstrVal;
+        if (domain.Length())
+        {
+          settings->RemoveWhiteListedDomain((BSTR)domain);
+        }
+      }
+      break;
+    case dispatchID_GetAppLocale:
+      {
+        if (pDispparams->cArgs != 0)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        pVarResult->vt = VT_BSTR;
+        pVarResult->bstrVal = SysAllocString(settings->GetAppLocale());
+      }
+      break;
+    case dispatchID_GetDocumentationLink:
+      {
+        if (pDispparams->cArgs != 0)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        pVarResult->vt = VT_BSTR;
+        pVarResult->bstrVal = SysAllocString(settings->GetDocumentationLink());
+      }
+      break;
+    case dispatchID_IsAcceptableAdsEnabled:
+      {
+        if (pDispparams->cArgs != 0)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        pVarResult->vt = VT_BOOL;
+        pVarResult->boolVal = CPluginClient::GetInstance()->IsAcceptableAdsEnabled() ? VARIANT_TRUE : VARIANT_FALSE;
+      }
+      break;
+    case dispatchID_SetAcceptableAdsEnabled:
+      {
+        if (pDispparams->cArgs != 1)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        if (pDispparams->rgvarg[0].vt != VT_BOOL)
+        {
+          return DISP_E_TYPEMISMATCH;
+        }
+        if (pDispparams->rgvarg[0].boolVal != VARIANT_FALSE)
+        {
+          CPluginClient* client = CPluginClient::GetInstance();
+          client->AddSubscription(client->GetPref(L"subscriptions_exceptionsurl", L""));
+        }
+        else
+        {
+          CPluginClient* client = CPluginClient::GetInstance();
+          client->RemoveSubscription(client->GetPref(L"subscriptions_exceptionsurl", L""));
+        }
+      }
+      break;
+    case dispatchID_IsUpdate:
+      {
+        if (pDispparams->cArgs != 0)
+        {
+          return DISP_E_BADPARAMCOUNT;
+        }
+        pVarResult->vt = VT_BOOL;
+        pVarResult->boolVal = CPluginClient::GetInstance()->GetPref(L"displayUpdatePage", false) ? VARIANT_TRUE : VARIANT_FALSE;
+      }
+      break;
+    default:
+      return DISP_E_MEMBERNOTFOUND;
+      break;
+    }
+  }
+  catch(...)
+  {
+    return E_FAIL;
+  }
   return S_OK;
 }