Add optional JamesDSP audio effects

frontend/vendor/jamesdsp/jamesdsp-node.js

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+import {DEFAULT_PARAMS, validateParam} from './params.js';
+const moduleLoads = new WeakMap();
+export class JamesDSPNode extends EventTarget {
+  static async create(context, {wasmURL=new URL('./dsp/jamesdsp.wasm',import.meta.url), workletURL=new URL('./worklet.js',import.meta.url)}={}) {
+    if (![44100,48000].includes(context.sampleRate)) throw new RangeError('Use a 44.1 or 48 kHz AudioContext');
+    if (!moduleLoads.has(context)) moduleLoads.set(context,new Map());
+    const cache=moduleLoads.get(context), key=String(workletURL);
+    if (!cache.has(key)) cache.set(key,context.audioWorklet.addModule(workletURL).catch(e=>{cache.delete(key);throw e;}));
+    const response=await fetch(wasmURL);
+    if (!response.ok) throw new Error(`WASM fetch failed: ${response.status}`);
+    const wasmBytes=await response.arrayBuffer();
+    await cache.get(key);
+    const wrapper=new JamesDSPNode(context,wasmBytes);
+    try { await wrapper.ready; return wrapper; } catch(e) { wrapper.destroy(); throw e; }
+  }
+  constructor(context,wasmBytes) {
+    super(); this.context=context; this.params={...DEFAULT_PARAMS}; this.texts={}; this.pending=new Map(); this.serial=0; this.destroyed=false; this.source=null;
+    this.node=new AudioWorkletNode(context,'jamesdsp',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2],channelCount:2,channelCountMode:'explicit',processorOptions:{wasmBytes}});
+    this.ready=new Promise((resolve,reject)=> {
+      const timer=setTimeout(()=>reject(new Error('DSP initialization timed out')),15000);
+      this.node.onprocessorerror=()=>{const error=new Error('DSP processor stopped');clearTimeout(timer);reject(error);this.fail(error);};
+      this.node.port.onmessage=({data})=> {
+        if(data.type==='ready') {clearTimeout(timer);resolve();}
+        else if(data.type==='reply') { const p=this.pending.get(data.id); if(p) {this.pending.delete(data.id);clearTimeout(p.timer);data.error?p.reject(new Error(data.error)):p.resolve(data.result);} }
+        else if(data.type==='error') {const error=new Error(data.error); clearTimeout(timer); reject(error); this.fail(error);}
+        else this.dispatchEvent(new CustomEvent(data.type,{detail:data}));
+      };
+    });
+  }
+  fail(error) { for(const p of this.pending.values()) {clearTimeout(p.timer);p.reject(error);} this.pending.clear();this.dispatchEvent(new CustomEvent('error',{detail:error})); }
+  request(type,data={}) {
+    if(this.destroyed) return Promise.reject(new Error('DSP has been destroyed'));
+    const id=++this.serial;
+    return new Promise((resolve,reject)=> {
+      const timer=setTimeout(()=>{this.pending.delete(id);reject(new Error(`DSP ${type} timed out`));},15000);
+      this.pending.set(id,{resolve,reject,timer});this.node.port.postMessage({type,id,...data});
+    });
+  }
+  // One source → this DSP → destination. For arbitrary graphs use .node directly.
+  connect(source,destination=this.context.destination) {
+    if(this.destroyed) throw new Error('DSP has been destroyed');
+    if(this.source) this.source.disconnect(this.node);
+    this.node.disconnect();this.source=source;source.connect(this.node);this.node.connect(destination);return destination;
+  }
+  async setParam(name,value) {validateParam(name,value);await this.request('param',{name,value});this.params[name]=value;}
+  setBypass(enabled) {return this.setParam('bypass',Number(Boolean(enabled)));}
+  async setText(effect,text) {
+    if(!['liveprog','ddc','arbitrary'].includes(effect) || typeof text!=='string' || text.length>65536) throw new RangeError('Invalid text effect');
+    await this.request('text',{effect,text});this.texts[effect]=text;this.params[`${effect}.enabled`]=0;
+  }
+  async loadIR(buffer) {
+    if(buffer.sampleRate!==this.context.sampleRate || ![1,2].includes(buffer.numberOfChannels) || buffer.length>65536 || buffer.length<1) throw new RangeError('IR must be mono/stereo, at context rate, at most 65536 frames');
+    const pcm=new Float32Array(buffer.length*buffer.numberOfChannels);
+    for(let ch=0;ch<buffer.numberOfChannels;ch++) {const data=buffer.getChannelData(ch);for(let i=0;i<buffer.length;i++) pcm[i*buffer.numberOfChannels+ch]=data[i];}
+    await this.request('ir',{pcm,frames:buffer.length,channels:buffer.numberOfChannels});this.params['convolver.enabled']=0;
+  }
+  async applyPreset(preset) {
+    // All keys validated before mutation; applying a preset resets unspecified params.
+    const params={...DEFAULT_PARAMS,...(preset.params||preset)};
+    for(const [name,value] of Object.entries(params)) validateParam(name,value);
+    for(const [effect,text] of Object.entries(preset.texts||{})) await this.setText(effect,text);
+    // Configure before enabling; text and IR resources must have been loaded.
+    for(const [name,value] of Object.entries(params).sort(([a],[b])=>Number(a.endsWith('.enabled'))-Number(b.endsWith('.enabled')))) await this.setParam(name,value);
+  }
+  toJSON() {return {version:1,params:{...this.params},texts:{...this.texts}};}
+  destroy() {
+    if(this.destroyed) return;
+    if(this.source) {try {this.source.disconnect(this.node);} catch {}} this.node.disconnect();
+    this.node.port.postMessage({type:'destroy'});this.destroyed=true;this.fail(new Error('DSP destroyed'));this.node.port.close();
+  }
+}