csound-wasm/src/index.js

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// eslint-disable-next-line no-unused-vars
import * as Comlink from 'comlink';
import VanillaWorkerMainThread from '@root/mains/vanilla.main';
import unmuteIosAudio from 'unmute-ios-audio';
import SharedArrayBufferMainThread from '@root/mains/sab.main';
import AudioWorkletMainThread from '@root/mains/worklet.main';
import ScriptProcessorNodeMainThread from '@root/mains/old-spn.main';
import wasmDataURI from '../lib/libcsound.wasm.zlib';
import log, { logSAB, logWorklet, logVAN } from '@root/logger';
import { areWorkletsSupportet, isSabSupported, isScriptProcessorNodeSupported } from '@root/utils';


let audioWorker, csoundWasmApi;

/**
 * The default entry for libcsound es7 module
 * @async
 * @return {Promise.<Object>}
 */
export async function Csound() {
  // prevent multiple initializations
  if (csoundWasmApi) {
    return csoundWasmApi;
  } else {
    unmuteIosAudio();
  }
  const workletSupport = areWorkletsSupportet();
  const spnSupport = isScriptProcessorNodeSupported();

  if (workletSupport) {
    logWorklet(`support detected`);
  } else if (spnSupport) {
    logVAN(`support detected`);
  } else {
    log.warn(`No WebAudio Support detected`);
  }

  if (workletSupport) {
    audioWorker = new AudioWorkletMainThread();
  } else if (spnSupport) {
    audioWorker = new ScriptProcessorNodeMainThread();
  }

  if (!audioWorker) {
    log.error('No detectable WebAudioAPI in current environment');
    return {};
  }

  const hasSABSupport = isSabSupported();

  if (!hasSABSupport) {
    log.warn(`SharedArrayBuffers not found, falling back to Vanilla concurrency`);
  } else {
    logSAB(`using SharedArrayBuffers`);
  }

  const worker =
    hasSABSupport && workletSupport
      ? new SharedArrayBufferMainThread(audioWorker, wasmDataURI)
      : new VanillaWorkerMainThread(audioWorker, wasmDataURI);

  if (worker) {
    log(`starting Csound thread initialization via WebWorker`);
    await worker.initialize();
    csoundWasmApi = worker.api;
  } else {
    log.error('No detectable WebAssembly support in current environment');
    return {};
  }

  return csoundWasmApi;
}

export default Csound;