StateMachineImp.cc

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// **************************************************************************
// **************************************************************************
#include "StateMachineImp.h"

#include "Time.h"
#include "Event.h"

#include "WindowLog.h"
#include "Converter.h"

#include "tools.h"

using namespace std;

// --------------------------------------------------------------------------
//
//
StateMachineImp::StateMachineImp(ostream &out, const std::string &name)
    : MessageImp(out), fName(name), fCurrentState(kSM_NotReady),
    fBufferEvents(true), fRunning(false), fExitRequested(0)
{
    SetDefaultStateNames();
}

// --------------------------------------------------------------------------
//
//
StateMachineImp::~StateMachineImp()
{
    // For this to work EventImp must be the first class from which
    // the object inherits
    for (vector<EventImp*>::iterator cmd=fListOfEvents.begin(); cmd!=fListOfEvents.end(); cmd++)
        delete *cmd;
}

// --------------------------------------------------------------------------
//
//
void StateMachineImp::SetDefaultStateNames()
{
    AddStateName(kSM_NotReady,   "NotReady", "State machine not ready, events are ignored.");
    AddStateName(kSM_Ready,      "Ready",    "State machine ready to receive events.");
    AddStateName(kSM_Error,      "ERROR",    "Common error state.");
    AddStateName(kSM_FatalError, "FATAL",    "A fatal error occured, the eventloop is stopped.");
}

// --------------------------------------------------------------------------
//
//
void StateMachineImp::PushEvent(Event *cmd)
{
    const lock_guard<mutex> guard(fMutex);
    fEventQueue.emplace_back(cmd);
    fCond.notify_one();
}

// --------------------------------------------------------------------------
//
//
shared_ptr<Event> StateMachineImp::PopEvent()
{
    const lock_guard<mutex> guard(fMutex);

    // Get the next event from the stack
    // and remove event from the stack
    const shared_ptr<Event> cmd = fEventQueue.front();
    fEventQueue.pop_front();
    return cmd;
}

// --------------------------------------------------------------------------
//
//
bool StateMachineImp::PostEvent(ostream &lout, const string &str)
{
    // Find the delimiter between the command name and the data
    size_t p0 = str.find_first_of(' ');
    if (p0==string::npos)
        p0 = str.length();

    // Compile the command which will be sent to the state-machine
    const string name = fName + "/" + str.substr(0, p0);

    // Check if this command is existing at all
    EventImp *evt = FindEvent(name);
    if (!evt)
    {
        lout << kRed << "Unknown command '" << name << "'" << endl;
        return false;
    }

    // Get the format of the event data
    const string fmt = evt->GetFormat();

    // Convert the user entered data according to the format string
    // into a data block which will be attached to the event
#ifndef DEBUG
    ostringstream sout;
    const Converter conv(sout, fmt, false);
#else
    const Converter conv(lout, fmt, false);
#endif
    if (!conv)
    {
        lout << kRed << "Couldn't properly parse the format... ignored." << endl;
        return false;
    }

    try
    {
#ifdef DEBUG
        lout << kBlue << name;
#endif
        const vector<char> v = conv.GetVector(str.substr(p0));
#ifdef DEBUG
        lout << endl;
#endif

        return PostEvent(*evt, v.data(), v.size());
    }
    catch (const std::runtime_error &e)
    {
        lout << endl << kRed << e.what() << endl;
    }

    return false;
}

// --------------------------------------------------------------------------
//
//
bool StateMachineImp::PostEvent(const EventImp &evt, const char *ptr, size_t siz)
{
    if (/*GetCurrentState()<0 ||*/ GetCurrentState()==kSM_FatalError)
    {
        Out() << kYellow << "State<0 or FatalError: Event ignored." << endl;
        return false;
    }

    if (IsRunning() || fBufferEvents)
    {
        Event *event = new Event(evt, ptr, siz);
        //Debug("Posted: "+event->GetName());
        PushEvent(event);
    }
    else
    {
        // FIXME: Is this thread safe? (Yes, because the data is copied)
        // But two handlers could be called at the same time. Do we
        // need to lock the handlers? (Dim + console)
        // FIXME: Is copying of the data necessary?
        const Event event(evt, ptr, siz);
        Lock();
        HandleEvent(event);
        UnLock();
    }
    return true;
}

// --------------------------------------------------------------------------
//
//
bool StateMachineImp::PostEvent(const EventImp &evt)
{
    if (/*GetCurrentState()<0 ||*/ GetCurrentState()==kSM_FatalError)
    {
        Out() << kYellow << "State<0 or FatalError: Event ignored." << endl;
        return false;
    }

    if (IsRunning() || fBufferEvents)
        PushEvent(new Event(evt));
    else
    {
        // FIXME: Is this thread safe? (Yes, because it is only used
        // by Dim and this is thread safe) But two handlers could
        // be called at the same time. Do we need to lock the handlers?
        HandleEvent(evt);
    }
    return true;
}

// --------------------------------------------------------------------------
//
//
const vector<string> StateMachineImp::GetEventNames()
{
    vector<string> v;

    const string &name = fName + "/";
    const int     len  = name.length();

    const lock_guard<mutex> guard(fMutexEvt);

    for (vector<EventImp*>::const_iterator i=fListOfEvents.begin();
         i!=fListOfEvents.end(); i++)
    {
        const string evt = (*i)->GetName();

        v.push_back(evt.substr(0, len)==name ? evt.substr(len) : evt);
    }

    return v;
}

// --------------------------------------------------------------------------
//
//
void StateMachineImp::PrintListOfEvents(ostream &out, const string &evt)
{
    const lock_guard<mutex> guard(fMutexEvt);

    for (vector<EventImp*>::const_iterator c=fListOfEvents.begin(); c!=fListOfEvents.end(); c++)
        if (evt.empty() || GetName()+'/'+evt==(*c)->GetName())
            (*c)->Print(out, true);
}

// --------------------------------------------------------------------------
//
//
void StateMachineImp::PrintListOfAllowedEvents(ostream &out)
{
    const lock_guard<mutex> guard(fMutexEvt);

    for (vector<EventImp*>::const_iterator c=fListOfEvents.begin(); c!=fListOfEvents.end(); c++)
        if ((*c)->IsStateAllowed(fCurrentState))
            (*c)->Print(out, true);
}

// --------------------------------------------------------------------------
//
//
//
void StateMachineImp::PrintListOfEvents(const string &str)
{
    PrintListOfEvents(Out(), str);
}

// --------------------------------------------------------------------------
//
//
void StateMachineImp::PrintListOfStates(std::ostream &out) const
{
    out << endl;
    out << kBold << "List of available states:" << endl;
    for (StateNames::const_iterator i=fStateNames.begin(); i!=fStateNames.end(); i++)
    {
        ostringstream state;
        state << i->first;
        out << " -[" << kBold << state.str() << kReset << "]:" << setfill(' ') << setw(6-state.str().length()) << ' ' << kYellow << i->second.first << kBlue << " (" << i->second.second << ")" << endl;
    }
    out << endl;
}

// --------------------------------------------------------------------------
//
//
void StateMachineImp::PrintListOfStates() const
{
    PrintListOfStates(Out());
}

// --------------------------------------------------------------------------
//
//
bool StateMachineImp::HasEvent(const EventImp *cmd)
{
    // Find the event from the list of commands and queue it
    const lock_guard<mutex> guard(fMutexEvt);
    return find(fListOfEvents.begin(), fListOfEvents.end(), cmd)!=fListOfEvents.end();
}

// --------------------------------------------------------------------------
//
//
EventImp *StateMachineImp::FindEvent(const string &evt)
{
    // Find the command from the list of commands and queue it
    const lock_guard<mutex> guard(fMutexEvt);
    for (vector<EventImp*>::const_iterator c=fListOfEvents.begin(); c!=fListOfEvents.end(); c++)
        if (evt == (*c)->GetName())
            return *c;

    return 0;
}

// --------------------------------------------------------------------------
//
//
EventImp &StateMachineImp::AddEvent(const string &name, const string &states, const string &fmt)
{
    EventImp *evt = CreateEvent(name, fmt);

    evt->AddAllowedStates(states);

#ifdef DEBUG
    Out() << ":   " << Time().GetAsStr("%H:%M:%S.%f");
    Out() << " - Adding command " << evt->GetName();
    Out() << endl;
#endif

    const lock_guard<mutex> guard(fMutexEvt);
    fListOfEvents.push_back(evt);
    return *evt;
}

// --------------------------------------------------------------------------
//
//
EventImp &StateMachineImp::AddEvent(const string &name, int s1, int s2, int s3, int s4, int s5)
{
    ostringstream str;
    str << s1 << ' '  << s2 << ' ' << s3 << ' ' << s4 << ' ' << s5;
    return AddEvent(name, str.str(), "");
}

// --------------------------------------------------------------------------
//
//
EventImp &StateMachineImp::AddEvent(const string &name, const string &fmt, int s1, int s2, int s3, int s4, int s5)
{
    ostringstream str;
    str << s1 << ' '  << s2 << ' ' << s3 << ' ' << s4 << ' ' << s5;
    return AddEvent(name, str.str(), fmt);
}

EventImp *StateMachineImp::CreateService(const string &)
{
    return new EventImp();
}

// --------------------------------------------------------------------------
//
EventImp &StateMachineImp::Subscribe(const string &name)
{
    EventImp *evt = CreateService(name);

    const lock_guard<mutex> guard(fMutexEvt);
    fListOfEvents.push_back(evt);
    return *evt;
}

void StateMachineImp::Unsubscribe(EventImp *evt)
{
    {
        const lock_guard<mutex> guard(fMutexEvt);

        auto it = find(fListOfEvents.begin(), fListOfEvents.end(), evt);
        if (it==fListOfEvents.end())
            return;

        fListOfEvents.erase(it);
    }
    delete evt;
}

// --------------------------------------------------------------------------
//
bool StateMachineImp::AddStateName(const int state, const std::string &name, const std::string &doc)
{
    //auto it = fStateNames.find(state);

    //if (/*it!=fStateNames.end() &&*/ !it->second.first.empty())
    //    return false;

    fStateNames[state] = make_pair(name, doc);
    return true;
}

// --------------------------------------------------------------------------
//
int StateMachineImp::GetStateIndex(const string &name) const
{
    for (auto it=fStateNames.begin(); it!=fStateNames.end(); it++)
        if (it->second.first==name)
            return it->first;

    return kSM_NotAvailable;
}

// --------------------------------------------------------------------------
//
const string StateMachineImp::GetStateName(int state) const
{
    const StateNames::const_iterator i = fStateNames.find(state);
    return i==fStateNames.end() || i->second.first.empty() ? to_string(state) : i->second.first;
}

// --------------------------------------------------------------------------
//
bool StateMachineImp::HasState(int state) const
{
    return fStateNames.find(state) != fStateNames.end();
}

// --------------------------------------------------------------------------
//
const string StateMachineImp::GetStateDesc(int state) const
{
    const StateNames::const_iterator i = fStateNames.find(state);
    return i==fStateNames.end() ? "" : i->second.second;
}

// --------------------------------------------------------------------------
//
//
const string StateMachineImp::GetStateDescription(int state) const
{
    const string &str = GetStateName(state);

    ostringstream s;
    s << state;
    if (str==s.str())
        return str;

    return str.empty() ? s.str() : (str+'['+s.str()+']');
}

// --------------------------------------------------------------------------
//
//
string StateMachineImp::SetCurrentState(int state, const char *txt, const std::string &cmd)
{
    if (state==fCurrentState)
    {
        Out() << " -- " << Time().GetAsStr("%H:%M:%S.%f") << " - State " << GetStateDescription(state) << " already set... ";
        if (!cmd.empty())
            Out() << "'" << cmd << "' ignored.";
        Out() << endl;
        return "";
    }

    const int old = fCurrentState;

    const string nold = GetStateDescription(old);
    const string nnew = GetStateDescription(state);

    string msg = nnew + " " + txt;
    if (!cmd.empty())
        msg += " (" + cmd + ")";

    fCurrentState = state;

    // State might have changed already again...
    // Not very likely, but possible. That's why state is used
    // instead of fCurrentState.

    ostringstream str;
    str << "State Transition from " << nold << " to " << nnew << " (" << txt;
    if (!cmd.empty())
        str << ": " << cmd;
    str << ")";
    Message(str);

    return msg;
}

// --------------------------------------------------------------------------
//
//
bool StateMachineImp::HandleNewState(int newstate, const EventImp *evt,
                                     const char *txt)
{
    if (newstate==kSM_FatalError)
        return false;

    if (newstate==fCurrentState || newstate==kSM_KeepState)
        return true;

    SetCurrentState(newstate, txt, evt ? evt->GetName() : "");

    return true;
}

// --------------------------------------------------------------------------
//
//
bool StateMachineImp::HandleEvent(const EventImp &evt)
{
    if (!evt.HasFunc())
    {
        Warn(evt.GetName()+": No function assigned... ignored.");
        return true;

    }

#ifdef DEBUG
    ostringstream out;
    out << "Handle: " << evt.GetName() << "[" << evt.GetSize() << "]";
    Debug(out);
#endif

    // Check if the received command is allow in the current state
    if (!evt.IsStateAllowed(fCurrentState))
    {
        Warn(evt.GetName()+": Not allowed in state "+GetStateDescription()+"... ignored.");
        return true;
    }

    return HandleNewState(evt.ExecFunc(), &evt,
                          "by ExecFunc function-call");
}

// --------------------------------------------------------------------------
//
//
int StateMachineImp::Run(bool dummy)
{
    if (fCurrentState>=kSM_Ready)
    {
        Error("Run() can only be called in the NotReady state.");
        return -1;
    }

    if (!fExitRequested)
    {
        fRunning = !dummy;

        SetCurrentState(kSM_Ready, "by Run()");

        std::unique_lock<std::mutex> lock(fMutex);
        fMutex.unlock();

        while (1)
        {
            fMutex.lock();
            if (IsQueueEmpty())
                fCond.wait_for(lock, chrono::microseconds(10000));
            fMutex.unlock();

            if (fExitRequested)
                break;

            if (dummy)
                continue;

            // If the command stack is empty go on with processing in the
            // current state
            if (!IsQueueEmpty())
            {
                // Pop the next command which arrived from the stack
                const shared_ptr<Event> cmd(PopEvent());
                if (!HandleEvent(*cmd))
                    break;
            }

            // Execute a step in the current state of the state machine
            if (!HandleNewState(Execute(), 0, "by Execute-command"))
                break;
        }

        fRunning = false;

        if (!fExitRequested)
        {
            Fatal("Fatal Error occured... shutting down.");
            return -1;
        }

        SetCurrentState(kSM_NotReady, "due to return from Run().");
    }

    const int exitcode = fExitRequested-1;

    // Prepare for next call
    fExitRequested = 0;

    return exitcode;
}

// --------------------------------------------------------------------------
//
//
void StateMachineImp::Stop(int code)
{
    fExitRequested = code+1;
}