allwpilib/src/nt_messagereader.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2015. All Rights Reserved.                             */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#include "nt_messagereader.h"

#include <cassert>
#include <cstdlib>
#include <cstring>

#include "nt_internal.h"
#include "nt_leb128.h"

using namespace NtImpl;

void
MessageHandler::anchor()
{
}

MessageReader::MessageReader(MessageHandler &handler,
                             raw_istream& is,
                             unsigned int proto_rev)
    : WireDecoder(is, proto_rev)
    , m_handler(handler)
{
}

MessageReader::~MessageReader()
{
}

bool
MessageReader::Run()
{
    unsigned int msg_type;
    if (!Read8(&msg_type)) return false;
    switch (msg_type)
    {
    case NT_MSG_KEEP_ALIVE:
        m_handler.GotKeepAlive();
        break;
    case NT_MSG_CLIENT_HELLO:
    {
        unsigned int proto_rev;
        if (!Read16(&proto_rev)) return false;
        NT_String self_id;
        NT_InitString(&self_id);
        // This intentionally uses the provided proto_rev instead of
        // m_proto_rev.
        if (proto_rev >= 0x0300u)
        {
            if (!ReadString(&self_id)) return false;
        }
        m_handler.GotClientHello(proto_rev, self_id);
        break;
    }
    case NT_MSG_PROTO_UNSUP:
    {
        unsigned int proto_rev;
        if (!Read16(&proto_rev)) return false;
        m_handler.GotProtoUnsup(proto_rev);
        break;
    }
    case NT_MSG_SERVER_HELLO_DONE:
        if (m_proto_rev < 0x0300u)
        {
            m_error = "received SERVER_HELLO_DONE in protocol < 3.0";
            return false;
        }
        m_handler.GotServerHelloDone();
        break;
    case NT_MSG_CLIENT_HELLO_DONE:
        if (m_proto_rev < 0x0300u)
        {
            m_error = "received CLIENT_HELLO_DONE in protocol < 3.0";
            return false;
        }
        m_handler.GotClientHelloDone();
        break;
    case NT_MSG_ENTRY_ASSIGN:
    {
        NT_String name;
        if (!ReadString(&name)) return false;
        NT_Type type;
        unsigned int id, seq_num;
        unsigned int flags = 0;
        NT_Value value;
        if (!ReadType(&type) ||
            !Read16(&id) ||
            !Read16(&seq_num) ||
            (m_proto_rev >= 0x0300u && !Read8(&flags)) ||
            !ReadValue(type, &value))
        {
            NT_DisposeString(&name);
            return false;
        }
        m_handler.GotEntryAssign(name, id, seq_num, value, flags);
        break;
    }
    case NT_MSG_ENTRY_UPDATE:
    {
        unsigned int id, seq_num;
        NT_Value value;
        if (!Read16(&id)) return false;
        if (!Read16(&seq_num)) return false;
        NT_Type type;
        if (m_proto_rev >= 0x0300u)
        {
            unsigned int itype;
            if (!Read8(&itype)) return false;
            type = static_cast<NT_Type>(itype);
        }
        else
            type = m_handler.GetEntryType(id);
        if (!ReadValue(type, &value)) return false;
            m_handler.GotEntryUpdate(id, seq_num, value);
        break;
    }
    case NT_MSG_FLAGS_UPDATE:
    {
        if (m_proto_rev < 0x0300u)
        {
            m_error = "received FLAGS_UPDATE in protocol < 3.0";
            return false;
        }
        unsigned int id, flags;
        if (!Read16(&id)) return false;
        if (!Read8(&flags)) return false;
        m_handler.GotFlagsUpdate(id, flags);
        break;
    }
    case NT_MSG_ENTRY_DELETE:
    {
        if (m_proto_rev < 0x0300u)
        {
            m_error = "received ENTRY_DELETE in protocol < 3.0";
            return false;
        }
        unsigned int id;
        if (!Read16(&id)) return false;
        m_handler.GotEntryDelete(id);
        break;
    }
    case NT_MSG_CLEAR_ENTRIES:
    {
        if (m_proto_rev < 0x0300u)
        {
            m_error = "received CLEAR_ENTRIES in protocol < 3.0";
            return false;
        }
        unsigned long magic;
        if (!Read32(&magic)) return false;
        if (magic != NT_CLEAR_ALL_MAGIC)
        {
            m_error = "received incorrect CLEAR_ENTRIES magic value, ignoring";
            return true;
        }
        m_handler.GotClearEntries();
        break;
    }
    case NT_MSG_EXECUTE_RPC:
    {
        if (m_proto_rev < 0x0300u)
        {
            m_error = "received EXECUTE_RPC in protocol < 3.0";
            return false;
        }
        unsigned int id, uid;
        if (!Read16(&id)) return false;
        if (!Read16(&uid)) return false;
        unsigned long size;
        if (!ReadULEB128(&size)) return false;
        char *params;
        if (!Read(&params, size)) return false;
        m_handler.GotExecuteRpc(id, uid, params, size);
        break;
    }
    case NT_MSG_RPC_RESPONSE:
    {
        if (m_proto_rev < 0x0300u)
        {
            m_error = "received RPC_RESPONSE in protocol < 3.0";
            return false;
        }
        unsigned int id, uid;
        if (!Read16(&id)) return false;
        if (!Read16(&uid)) return false;
        unsigned long size;
        if (!ReadULEB128(&size)) return false;
        char *results;
        if (!Read(&results, size)) return false;
        m_handler.GotRpcResponse(id, uid, results, size);
        break;
    }
    default:
        m_error = "unrecognized message type";
        return false;
    }
    return true;
}