Issue 5013 - Improve some const-correctness

src/DefaultWebRequestCurl.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 126 matching lines @@
     curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
     curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
     curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, ReceiveData);
     curl_easy_setopt(curl, CURLOPT_WRITEDATA, &responseText);
     // Request compressed data. Using any supported aglorithm
     curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, "");
     curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, ReceiveHeader);
     curl_easy_setopt(curl, CURLOPT_HEADERDATA, &headerData);
 
     struct curl_slist* headerList = 0;
-    for (HeaderList::const_iterator it = requestHeaders.begin();
-      it != requestHeaders.end(); ++it)
+    for (auto it = requestHeaders.cbegin(); it != requestHeaders.cend(); ++it)
     {
       headerList = curl_slist_append(headerList, (it->first + ": " + it->second).c_str());
     }
     if (headerList)
       curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerList);
 
     result.status = ConvertErrorCode(curl_easy_perform(curl));
     result.responseStatus = headerData.status;
     result.responseText = responseText.str();
-    for (std::vector<std::string>::iterator it = headerData.headers.begin();
-        it != headerData.headers.end(); ++it)
+    for (auto it = headerData.headers.cbegin(); it != headerData.headers.cend(); ++it)
     {
       // Parse header name and value out of something like "Foo: bar"
       std::string header = *it;
       size_t colonPos = header.find(':');
       if (colonPos != std::string::npos)
       {
         size_t nameStart = 0;
         size_t nameEnd = colonPos;
         while (nameEnd > nameStart && isspace(header[nameEnd - 1]))
           nameEnd--;
@@ skipping 13 matching lines @@
         }
       }
     }
 
     if (headerList)
       curl_slist_free_all(headerList);
     curl_easy_cleanup(curl);
   }
   return result;
 }