Via Reaper's SetExtState(...), notify interested applications as to which tracks are visible on the control surface

[Christopher Norman]

Hi there,

I’ve been working on an enhanced meter bridge for control surfaces. In order enable the bridge’s display to sync to control surface I’ve hastily, dirtily and windows-only-ly modified the MCU plugin as per the code snippet. In this guise it isn’t cross-platform, as it uses Windows mutexes as opposed to those from Boost, which are a file lock, not a mutex.

Any chance we could have this for the benefit of the broader community?

Best regards,

CJPN

String m_cjpn_previous_successful_track_visible_GUIDs = "";

void Tracks::updateTrackStates(int numMCUChannels) {
    BOOST_FOREACH(tTrackStates::value_type & v, m_trackStates) {
        if (!v.second -> getMediaTrack())
            continue;

        v.second -> setIsOnMCUChannel(0);

        if (m_pOptions2 -> isOptionSetTo(MTO2_TCP_ADJUCT, MTO2A_TCP_NO)) {
            v.second -> setIsShownInTCP(
                MediaTrackInfo::isShownInTCP(v.second -> getMediaTrack()));
            v.second -> setTCPHeight(
                MediaTrackInfo::getHeight(v.second -> getMediaTrack()));
        }

        if (m_pOptions2 -> isOptionSetTo(MTO2_MCP_ADJUCT, MTO2A_MCP_NO)) {
            v.second -> setIsShownInMCP(
                MediaTrackInfo::isShownInMCP(v.second -> getMediaTrack()));
        }
    }
    //CJPN
    String ext_section = "Control_Surface_Klinke";
    String ext_key = "Visible_Tracks_By_GUID";
    String cjpn_visible_tracks_guids = "";

    for (int c = 1; c <= numMCUChannels; c++) {
        MediaTrack * pMT = getMediaTrackForChannel(c);

        //CJPN
        if (c > 1) cjpn_visible_tracks_guids += ",";

        if (pMT == NULL) {
            //CJPN
            cjpn_visible_tracks_guids += "NULL";

            continue;
        }

        TrackState * pTS = getTrackStateForMediaTrack(pMT);

        //CJPN
        cjpn_visible_tracks_guids += pTS -> getGuidAsString();

        safe_call(pTS, setIsOnMCUChannel(c));
    }

    //CJPN notify Reaper of tracks visible on the control surface.  This, in turn, can be consumed by any interested party by locking the mutex and calling GetExtState on "Control_Surface" / "Visible_Tracks_By_GUID"
    //Assumes we're single-threaded by this point.  Chaos will ensue if we're called by multiple threads.
    bool lock_success = false;
    bool hasNotifiedReaper = false;
    if (!m_cjpn_previous_successful_track_visible_GUIDs.equalsIgnoreCase(cjpn_visible_tracks_guids)) {
        try {
            //Notify Reaper.
            lock_success = reaper_extstate_mutex.lock(10); //Wait for 10ms 
            if (lock_success) {
                SetExtState(ext_section.toCString(), ext_key.toCString(), cjpn_visible_tracks_guids.toCString(), false); //false for non-persisted

                //Other synchronised shenanigans here?

                //IMPORTANT! This must be the last line in the lock
                hasNotifiedReaper = true;
            }
        } catch (...) {
            //Play dumb
            int breakhere = 123;
        }

        if (lock_success)
            reaper_extstate_mutex.unlock();

        //Keep a record to prevent spamming of Reaper SetExtState API, yet keep trying until the call to SetExtState, or antyhing else in the muxex-lock, has succeeded in response to a change of state.
        if (hasNotifiedReaper)
            m_cjpn_previous_successful_track_visible_GUIDs = cjpn_visible_tracks_guids;
    }
}

‌

[Christopher Norman]

Further up the class:

‌

#include "NamedMutex.h"

NamedMutex reaper_extstate_mutex;

Tracks::Tracks(void)
    : m_pCurrentBaseTrack(NULL), m_pOptions1(NULL), m_pOptions2(NULL),
      m_globalOffset(0) {
  m_selectedTracks.clear();
  m_pAllTracksBefore = new tTrackSet();
  m_pAllTracksNow = new tTrackSet();

  m_projectChangedConnectionId =
      ProjectConfig::instance()->connect2ProjectChangeSignal(
          boost::bind(&Tracks::projectChanged, this, _1, _2));

  try 
  {
      reaper_extstate_mutex = NamedMutex(L"Global\\com.cjpn.reaper.extstate.Control_Surface_Klinke.Visible_Tracks_By_GUID.B528D44C-702D-4EF1-A1C1-9DF78CD69E1A");
  }
  catch (...)
  {
      //Well, that went horribly wrong
  }
}

‌

[Steffen Fuerst]

Hmm, I am not sure. Can you please tell me more about this project (do you have a link)? And how many users does it have?

‌

[Christopher Norman]

I’m not entirely certain you’re following the logic.

[Christopher Norman]

You could name the mutex anything you like.

[Christopher Norman]

To put it to you directly I have a cross-platform (WIn/IOS/Android) meter bridge working locally and over network.

[Christopher Norman]

People, sooner or later, will desire a better meter bridge for their Mackie Control. Or similar. Especially if they can merely use an old phone.