Issue 5180 - introduce asynchronous web request

include/AdblockPlus/IWebRequest.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef ADBLOCK_PLUS_WEB_REQUEST_H
-#define ADBLOCK_PLUS_WEB_REQUEST_H
+#ifndef ADBLOCK_PLUS_IWEB_REQUEST_H
+#define ADBLOCK_PLUS_IWEB_REQUEST_H
 
+#include <cstdint>
+#include <functional>
 #include <memory>
-#include <stdint.h>
+#include <vector>
 #include <string>
-#include <vector>
 
 namespace AdblockPlus
 {
   /**
    * List of HTTP headers.
    */
-  typedef std::vector<std::pair<std::string, std::string> > HeaderList;
+  typedef std::vector<std::pair<std::string, std::string>> HeaderList;
 
   /**
    * HTTP response.
    */
   struct ServerResponse
   {
     //@{
     /**
      * [Mozilla status code](https://developer.mozilla.org/en/docs/Table_Of_Errors#Network_Errors)
      * indicating the network-level request status.
@@ skipping 17 matching lines @@
      */
     int responseStatus;
 
     /**
      * Body text of the response.
      */
     std::string responseText;
   };
 
   /**
-   * Web request interface.
+   * Web request interface used to implement XMLHttpRequest.
    */
-  class WebRequest
+  struct IWebRequest
   {
-  public:
     /**
      * Possible [Mozilla status codes](https://developer.mozilla.org/en/docs/Table_Of_Errors#Network_Errors).
      */
-    enum
+    enum MozillaStatusCode
     {
       NS_OK = 0,
       NS_ERROR_FAILURE = 0x80004005,
       NS_ERROR_OUT_OF_MEMORY = 0x8007000e,
       NS_ERROR_MALFORMED_URI = 0x804b000a,
       NS_ERROR_CONNECTION_REFUSED = 0x804b000d,
       NS_ERROR_NET_TIMEOUT = 0x804b000e,
       NS_ERROR_NO_CONTENT = 0x804b0011,
       NS_ERROR_UNKNOWN_PROTOCOL = 0x804b0012,
       NS_ERROR_NET_RESET = 0x804b0014,
       NS_ERROR_UNKNOWN_HOST = 0x804b001e,
       NS_ERROR_REDIRECT_LOOP = 0x804b001f,
       NS_ERROR_UNKNOWN_PROXY_HOST = 0x804b002a,
       NS_ERROR_NET_INTERRUPT = 0x804b0047,
       NS_ERROR_UNKNOWN_PROXY_CONNECTION_REFUSED = 0x804b0048,
       NS_CUSTOM_ERROR_BASE = 0x80850000,
       NS_ERROR_NOT_INITIALIZED = 0xc1f30001
     };
 
-    virtual inline ~WebRequest() {};
+    /**
+     * Callback type invoked when the server response is ready.
+     * The parameter is the server response.
+     */
+    typedef std::function<void(const ServerResponse&)> GetCallback;
+    virtual ~IWebRequest() {};
 
     /**
      * Performs a GET request.
      * @param url Request URL.
      * @param requestHeaders Request headers.
-     * @return HTTP response.
+     * @param getCallback to invoke when the server response is ready.
      */
-    virtual ServerResponse GET(const std::string& url, const HeaderList& requestHeaders) const = 0;
+    virtual void GET(const std::string& url, const HeaderList& requestHeaders, const GetCallback& getCallback) = 0;
   };
 
   /**
-   * Shared smart pointer to a `WebRequest` instance.
+   * Unique smart pointer to an instance of `IWebRequest` implementation.
    */
-  typedef std::shared_ptr<WebRequest> WebRequestSharedPtr;
+  typedef std::unique_ptr<IWebRequest> WebRequestPtr;
 }
 
 #endif