WIP with compressors, filters, heavy worklets

packages/superdough/nodePools.mjs

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+/*
+nodePools.mjs - Helper functions related to pooling and re-using audio nodes
+
+Copyright (C) 2025 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/superdough/nodePools.mjs>
+This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+const nodePools = new Map();
+const POOL_KEY = Symbol('nodePoolKey');
+const IS_WORKLET_DEAD = Symbol('nodePoolIsWorkletDead');
+const MAX_POOL_SIZE = 64;
+
+export const isPoolable = (node) => !!node[POOL_KEY];
+
+const getParams = (node) => {
+  const params = new Set();
+  node.parameters?.forEach((param) => params.add(param));
+  const visited = new Set(); // prioritize deepest definition
+  let proto = node;
+  // Move up the prototype chain
+  while (proto !== Object.prototype) {
+    for (const key of Object.getOwnPropertyNames(proto)) {
+      if (visited.has(key)) continue;
+      visited.add(key);
+      const value = node[key];
+      if (value instanceof AudioParam) {
+        params.add(value);
+      }
+    }
+    proto = Object.getPrototypeOf(proto);
+  }
+  return params;
+};
+
+export const releaseNodeToPool = (node) => {
+  node.disconnect();
+  if (node instanceof AudioScheduledSourceNode) {
+    // not reusable
+    return;
+  }
+  // Fallback to a type-based key if the node was not created via getNodeFromPool
+  const key = node[POOL_KEY];
+  if (key == null) return;
+  const now = node.context?.currentTime ?? 0;
+  getParams(node).forEach((param) => param.cancelScheduledValues(now));
+  const pool = nodePools.get(key) ?? [];
+  if (pool.length < MAX_POOL_SIZE) {
+    pool.push(new WeakRef(node));
+    nodePools.set(key, pool);
+  }
+};
+
+export const markWorkletAsDead = (worklet) => (worklet[IS_WORKLET_DEAD] = true);
+
+// Attempt to get node from the pool. If this fails, fall back
+// to building it with the factory
+export const getNodeFromPool = (key, factory) => {
+  const pool = nodePools.get(key) ?? [];
+  let node;
+  while (pool.length) {
+    const ref = pool.pop();
+    node = ref?.deref();
+    if (node != null && !node[IS_WORKLET_DEAD]) break;
+  }
+  if (node == null || node[IS_WORKLET_DEAD]) {
+    node = factory();
+  }
+  node[POOL_KEY] = key;
+  return node;
+};