Re: [Jsonrpc-cpp-devel] Scons error: "ambiguous overload"

[Eamonn H. <eam...@al...>]

Hi,

Many thanks for the message.

I'm on Ubuntu Linux, 64-bit, g++ 4.5.2.

I think I've managed to solve this problem:

Here's what I did on lines 208 and 213 - I just casted the indexes:

Process(root[(Json::Value::ArrayIndex)i], ret); //line 208

response[(Json::Value::ArrayIndex)j] = ret; //line 213

Hope this helps,

Eamonn






----- Original Message -----
From: "Sebastien Vincent" <seb...@cp...>
To: "Eamonn Hynes" <eam...@al...>
Cc: jso...@li...
Sent: Monday, 8 August, 2011 5:14:26 PM
Subject: Re: [Jsonrpc-cpp-devel] Scons error: "ambiguous overload"

Hi,

What is your environment (OS, g++ version, jsoncpp version, ...) ?
 
--
Seb


On Mon, 8 Aug 2011 10:27:11 +0100 (IST), Eamonn Hynes
<eam...@al...> wrote:
> I hope someone can help me get jsonrpc-cpp to compile.
> 
> When I type `scons` as per the documentation, I get:
> 
>  eamorr@Compaq6000:~/Desktop/jsonrpc-cpp$ scons
>  scons: Reading SConscript files ...
>  scons: done reading SConscript files.
>  scons: Building targets ...
>  g++ -o src/jsonrpc_handler.os -c -std=c++98 -Wall -Wextra -pedantic
> -Wredundant-decls -Wshadow -Werror -O2 -fPIC src/jsonrpc_handler.cpp
>  src/jsonrpc_handler.cpp: In member function ‘bool
> Json::Rpc::Handler::Process(const std::string&, Json::Value&)’:
>  src/jsonrpc_handler.cpp:208:25: error: ambiguous overload for
> ‘operator[]’ in ‘root[i]’
>  /usr/local/include/json/value.h:322:14: note: candidates are:
> Json::Value& Json::Value::operator[](Json::Value::ArrayIndex)
>  /usr/local/include/json/value.h:329:14: note: Json::Value&
> Json::Value::operator[](int)
>  /usr/local/include/json/value.h:334:20: note: const Json::Value&
> Json::Value::operator[](Json::Value::ArrayIndex) const
>  /usr/local/include/json/value.h:339:20: note: const Json::Value&
> Json::Value::operator[](int) const
>  src/jsonrpc_handler.cpp:213:23: error: ambiguous overload for
> ‘operator[]’ in ‘response[j]’
>  /usr/local/include/json/value.h:322:14: note: candidates are:
> Json::Value& Json::Value::operator[](Json::Value::ArrayIndex)
>  /usr/local/include/json/value.h:329:14: note: Json::Value&
> Json::Value::operator[](int)
>  /usr/local/include/json/value.h:334:20: note: const Json::Value&
> Json::Value::operator[](Json::Value::ArrayIndex) const
>  /usr/local/include/json/value.h:339:20: note: const Json::Value&
> Json::Value::operator[](int) const
>  scons: *** [src/jsonrpc_handler.os] Error 1
>  scons: building terminated because of errors.
> 
> Here is `src/jsonrpc_handler.cpp` (I've marked lines 208 and 213):
> 
>  /*
>  * JsonRpc-Cpp - JSON-RPC implementation.
>  * Copyright (C) 2008-2011 Sebastien Vincent 
>  *
>  * This program is free software: you can redistribute it and/or
> modify
>  * it under the terms of the GNU Lesser General Public License as
> published by
>  * the Free Software Foundation, either version 3 of the License, or
>  * (at your option) any later version.
>  *
>  * This program 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 Lesser General Public License for more details.
>  *
>  * You should have received a copy of the GNU Lesser General Public
> License
>  * along with this program. If not, see .
>  */
> 
>  /**
>  * file jsonrpc_handler.cpp
>  * brief JSON-RPC server processor engine.
>  * author Sebastien Vincent
>  */
> 
>  #include "jsonrpc_handler.h"
> 
>  namespace Json
>  {
> 
>  namespace Rpc
>  {
> 
>  CallbackMethod::~CallbackMethod()
>  {
>  }
> 
>  Handler::Handler()
>  {
>  /* add a RPC method that list the actual RPC methods contained in
> the Handler */
>  Json::Value root;
> 
>  root["description"] = "List the RPC methods available";
>  root["parameters"] = Json::Value::null;
>  root["returns"] = "Object that contains description of all methods
> registered";
> 
>  AddMethod(new RpcMethod(*this, &Handler::SystemDescribe,
> std::string("system.describe"), root));
>  }
> 
>  Handler::~Handler()
>  {
>  /* delete all objects from the list */
>  for(std::list::const_iterator it = m_methods.begin() ; it !=
> m_methods.end() ; it++)
>  {
>  delete (*it);
>  }
>  m_methods.clear();
>  }
> 
>  void Handler::AddMethod(CallbackMethod* method)
>  {
>  m_methods.push_back(method);
>  }
> 
>  void Handler::DeleteMethod(const std::string& name)
>  {
>  /* do not delete system defined method */
>  if(name == "system.describe")
>  {
>  return;
>  }
> 
>  for(std::list::iterator it = m_methods.begin() ; it !=
> m_methods.end() ; it++)
>  {
>  if((*it)->GetName() == name)
>  {
>  delete (*it);
>  m_methods.erase(it);
>  break;
>  }
>  }
>  }
> 
>  bool Handler::SystemDescribe(const Json::Value& msg, Json::Value&
> response)
>  {
>  Json::Value methods;
>  response["jsonrpc"] = "2.0";
>  response["id"] = msg["id"];
> 
>  for(std::list::iterator it = m_methods.begin() ; it !=
> m_methods.end() ; it++)
>  {
>  methods[(*it)->GetName()] = (*it)->GetDescription();
>  }
> 
>  response["result"] = methods;
>  return true;
>  }
> 
>  std::string Handler::GetString(Json::Value value)
>  {
>  return m_writer.write(value);
>  }
> 
>  bool Handler::Check(const Json::Value& root, Json::Value& error)
>  {
>  Json::Value err;
> 
>  /* check the JSON-RPC version => 2.0 */
>  if(!root.isObject() || !root.isMember("jsonrpc") || root["jsonrpc"]
> != "2.0") 
>  {
>  error["id"] = Json::Value::null;
>  error["jsonrpc"] = "2.0";
> 
>  err["code"] = INVALID_REQUEST;
>  err["message"] = "Invalid JSON-RPC request.";
>  error["error"] = err;
>  return false;
>  }
> 
>  if(root.isMember("id") && (root["id"].isArray() ||
> root["id"].isObject()))
>  {
>  error["id"] = Json::Value::null;
>  error["jsonrpc"] = "2.0";
> 
>  err["code"] = INVALID_REQUEST;
>  err["message"] = "Invalid JSON-RPC request.";
>  error["error"] = err;
>  return false;
>  }
> 
>  /* extract "method" attribute */
>  if(!root.isMember("method") || !root["method"].isString())
>  {
>  error["id"] = Json::Value::null;
>  error["jsonrpc"] = "2.0";
> 
>  err["code"] = INVALID_REQUEST;
>  err["message"] = "Invalid JSON-RPC request.";
>  error["error"] = err;
>  return false;
>  }
> 
>  return true;
>  }
> 
>  bool Handler::Process(const Json::Value& root, Json::Value&
> response)
>  {
>  Json::Value error;
>  std::string method;
> 
>  if(!Check(root, error))
>  {
>  response = error;
>  return false;
>  }
> 
>  method = root["method"].asString();
> 
>  if(method != "")
>  {
>  CallbackMethod* rpc = Lookup(method);
>  if(rpc)
>  {
>  return rpc->Call(root, response);
>  }
>  }
> 
>  /* forge an error response */
>  response["id"] = root.isMember("id") ? root["id"] :
> Json::Value::null;
>  response["jsonrpc"] = "2.0";
> 
>  error["code"] = METHOD_NOT_FOUND;
>  error["message"] = "Method not found.";
>  response["error"] = error;
> 
>  return false;
>  }
> 
>  bool Handler::Process(const std::string& msg, Json::Value& response)
>  {
>  Json::Value root;
>  Json::Value error;
>  bool parsing = false;
> 
>  /* parsing */
>  parsing = m_reader.parse(msg, root);
> 
>  if(!parsing)
>  {
>  /* request or batched call is not in JSON format */
>  response["id"] = Json::Value::null;
>  response["jsonrpc"] = "2.0";
> 
>  error["code"] = PARSING_ERROR;
>  error["message"] = "Parse error.";
>  response["error"] = error; 
>  return false;
>  }
> 
>  if(root.isArray())
>  {
>  /* batched call */
>  size_t i = 0;
>  size_t j = 0;
> 
>  for(i = 0 ; i < root.size() ; i++)
>  {
>  Json::Value ret;
>  Process(root[i], ret); //line 208!
> 
>  if(ret != Json::Value::null)
>  {
>  /* it is not a notification, add to array of responses */
>  response[j] = ret; //line 213!
>  j++;
>  }
>  }
>  return true;
>  }
>  else
>  {
>  return Process(root, response);
>  }
>  }
> 
>  bool Handler::Process(const char* msg, Json::Value& response)
>  {
>  std::string str(msg);
> 
>  return Process(str, response);
>  }
> 
>  CallbackMethod* Handler::Lookup(const std::string& name) const
>  {
>  for(std::list::const_iterator it = m_methods.begin() ; it !=
> m_methods.end() ; it++)
>  {
>  if((*it)->GetName() == name)
>  {
>  return (*it);
>  }
>  }
> 
>  return 0;
>  }
> 
>  } /* namespace Rpc */
> 
>  } /* namespace Json */
> 
> I'm really hoping someone might be able to point me in the right
> direction.
> 
> Many thanks in advance,