chore(release): prepare v0.18.6

scripts/media-background-queue.js

@@ -0,0 +1,54 @@
+export function createBackgroundJobQueue({ concurrency = 2, worker, onError = null } = {}) {
+  if (!Number.isInteger(concurrency) || concurrency < 1) throw new Error('队列并发数必须是正整数')
+  if (typeof worker !== 'function') throw new Error('队列缺少 worker')
+
+  const pending = []
+  const pendingIds = new Set()
+  const activeIds = new Set()
+  const idleWaiters = new Set()
+
+  function settleIdleWaiters() {
+    if (pending.length || activeIds.size) return
+    for (const resolve of idleWaiters) resolve()
+    idleWaiters.clear()
+  }
+
+  function drain() {
+    while (activeIds.size < concurrency && pending.length) {
+      const jobId = pending.shift()
+      pendingIds.delete(jobId)
+      activeIds.add(jobId)
+      Promise.resolve()
+        .then(() => worker(jobId))
+        .catch(error => onError?.(jobId, error))
+        .finally(() => {
+          activeIds.delete(jobId)
+          drain()
+          settleIdleWaiters()
+        })
+    }
+    settleIdleWaiters()
+  }
+
+  return {
+    enqueue(jobId) {
+      const id = String(jobId || '').trim()
+      if (!id || pendingIds.has(id) || activeIds.has(id)) return false
+      pending.push(id)
+      pendingIds.add(id)
+      queueMicrotask(drain)
+      return true
+    },
+    has(jobId) {
+      const id = String(jobId || '').trim()
+      return pendingIds.has(id) || activeIds.has(id)
+    },
+    stats() {
+      return { active: activeIds.size, pending: pending.length }
+    },
+    whenIdle() {
+      if (!pending.length && !activeIds.size) return Promise.resolve()
+      return new Promise(resolve => idleWaiters.add(resolve))
+    },
+  }
+}