panic_broadcaster.hpp

00001 /*
00002  * Copyright (C) 2014 Pavel Kirienko <pavel.kirienko@gmail.com>
00003  */
00004 
00005 #ifndef UAVCAN_PROTOCOL_PANIC_BROADCASTER_HPP_INCLUDED
00006 #define UAVCAN_PROTOCOL_PANIC_BROADCASTER_HPP_INCLUDED
00007 
00008 #include <uavcan/debug.hpp>
00009 #include <uavcan/node/publisher.hpp>
00010 #include <uavcan/node/timer.hpp>
00011 #include <uavcan/protocol/Panic.hpp>
00012 
00013 namespace uavcan
00014 {
00015 /**
00016  * Helper for broadcasting the message uavcan.protocol.Panic.
00017  */
00018 class UAVCAN_EXPORT PanicBroadcaster : private TimerBase
00019 {
00020     Publisher<protocol::Panic>  pub_;
00021     protocol::Panic msg_;
00022 
00023     void publishOnce()
00024     {
00025         const int res = pub_.broadcast(msg_);
00026         if (res < 0)
00027         {
00028             pub_.getNode().registerInternalFailure("Panic pub failed");
00029         }
00030     }
00031 
00032     virtual void handleTimerEvent(const TimerEvent&)
00033     {
00034         publishOnce();
00035     }
00036 
00037 public:
00038     explicit PanicBroadcaster(INode& node)
00039         : TimerBase(node)
00040         , pub_(node)
00041     { }
00042 
00043     /**
00044      * This method does not block and can't fail.
00045      * @param short_reason              Short ASCII string that describes the reason of the panic, 7 characters max.
00046      *                                  If the string exceeds 7 characters, it will be truncated.
00047      * @param broadcasting_period       Broadcasting period. Optional.
00048      * @param priority                  Transfer priority. Optional.
00049      */
00050     void panic(const char* short_reason_description,
00051                MonotonicDuration broadcasting_period = MonotonicDuration::fromMSec(100),
00052                const TransferPriority priority = TransferPriority::Default)
00053     {
00054         msg_.reason_text.clear();
00055         const char* p = short_reason_description;
00056         while (p && *p)
00057         {
00058             if (msg_.reason_text.size() == msg_.reason_text.capacity())
00059             {
00060                 break;
00061             }
00062             msg_.reason_text.push_back(protocol::Panic::FieldTypes::reason_text::ValueType(*p));
00063             p++;
00064         }
00065 
00066         UAVCAN_TRACE("PanicBroadcaster", "Panicking with reason '%s'", getReason().c_str());
00067 
00068         pub_.setTxTimeout(broadcasting_period);
00069         pub_.setPriority(priority);
00070 
00071         publishOnce();
00072         startPeriodic(broadcasting_period);
00073     }
00074 
00075     /**
00076      * Stop broadcasting immediately.
00077      */
00078     void dontPanic()    // Where's my towel
00079     {
00080         stop();
00081         msg_.reason_text.clear();
00082     }
00083 
00084     bool isPanicking() const { return isRunning(); }
00085 
00086     const typename protocol::Panic::FieldTypes::reason_text& getReason() const
00087     {
00088         return msg_.reason_text;
00089     }
00090 };
00091 
00092 }
00093 
00094 #endif // UAVCAN_PROTOCOL_PANIC_BROADCASTER_HPP_INCLUDED