130 lines
3.5 KiB
Nim
130 lines
3.5 KiB
Nim
# This requires the 'threading' module and either nim 1.9+
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# or --threads:on:
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#
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# nimble install threading
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#
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import std/[isolation, logging, os, strformat]
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import threading/channels
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import signal
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import jacket
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var
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jclient: ClientP
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event: MidiEvent
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midiPort: PortP
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midiEventChan: Chan[MidiEvent]
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midiEventPrinter: Thread[void]
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status: cint
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exitSignalled: bool = false
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var log = newConsoleLogger(when defined(release): lvlInfo else: lvlDebug)
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proc cleanup() =
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debug "Cleaning up..."
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if jclient != nil:
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debug "Deactivating JACK client..."
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discard jclient.deactivate()
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if midiEventPrinter.running:
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debug "Stopping MIDI event printer thread..."
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# Receiving an invalid event causes receiving thread to wake up and
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# break its endless loop
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event.size = 0
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midiEventChan.send(event)
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midiEventPrinter.joinThread()
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if jclient != nil:
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debug "Closing JACK client..."
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discard jclient.clientClose()
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jclient = nil
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debug "Bye."
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proc errorCb(msg: cstring) {.cdecl.} =
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# Suppress verbose JACK error messages when server is not available by
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# default. Pass ``lvlAll`` when creating the logger to enable them.
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debug "JACK error: " & $msg
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proc signalCb(sig: cint) {.noconv.} =
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debug "Received signal: " & $sig
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exitSignalled = true
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proc shutdownCb(arg: pointer = nil) {.cdecl.} =
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warn "JACK server has shut down."
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exitSignalled = true
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proc midiEventPrinterProc() =
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var event: MidiEvent
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while true:
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midiEventChan.recv(event)
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if event.size == 0:
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break
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elif event.size <= 3:
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for i in 0..<event.size:
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stdout.write(fmt"0x{event.buffer[i]:02X} ")
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stdout.write("\n")
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stdout.flushFile()
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proc processCb*(nFrames: NFrames, arg: pointer): cint {.cdecl.} =
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var event: MidiEvent
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let inbuf = portGetBuffer(midiPort, nFrames)
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let count = midiGetEventCount(inbuf)
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for i in 0..<count:
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if midiEventGet(event.addr, inbuf, i.uint32) == 0:
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if not midiEventChan.trySend(event):
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warn "MIDI event channel overflow!"
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proc main() =
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addHandler(log)
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# Create JACK client
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setErrorFunction(errorCb)
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jclient = clientOpen("jacket_midi_print", NoStartServer or UseExactName, status.addr)
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debug "JACK server status: " & $status
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if jclient == nil:
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error getJackStatusErrorString(status)
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quit QuitFailure
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# Set up signal handlers to clean up on exit
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when defined(windows):
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setSignalProc(signalCb, SIGABRT, SIGINT, SIGTERM)
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else:
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setSignalProc(signalCb, SIGABRT, SIGHUP, SIGINT, SIGQUIT, SIGTERM)
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# Set up a thread, which receives MIDI events from process callback via a
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# Channel and prints them without danger of blocking the process callback
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midiEventChan = newChan[MidiEvent]()
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createThread(midiEventPrinter, midiEventPrinterProc)
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# Register JACK callbacks
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if jclient.setProcessCallback(processCb) != 0:
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error "Could not set JACK process callback function."
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cleanup()
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quit QuitFailure
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jclient.onShutdown(shutdownCb)
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# Create output port
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midiPort = jclient.portRegister("midi_in", JACK_DEFAULT_MIDI_TYPE, PortIsInput, 0)
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# Activate JACK client ...
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if jclient.activate() == 0:
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# ... and keep running until a signal is received
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while not exitSignalled:
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sleep(200)
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cleanup()
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when isMainModule:
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main()
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