feat(nbstore): new doc sync engine (#8918)

packages/common/nbstore/src/utils/priority-queue.ts

@@ -0,0 +1,69 @@
+import { BinarySearchTree } from '@datastructures-js/binary-search-tree';
+
+export class PriorityQueue {
+  tree = new BinarySearchTree<{ id: string; priority: number }>((a, b) => {
+    return a.priority === b.priority
+      ? a.id === b.id
+        ? 0
+        : a.id > b.id
+          ? 1
+          : -1
+      : a.priority - b.priority;
+  });
+  priorityMap = new Map<string, number>();
+
+  push(id: string, priority: number = 0) {
+    const oldPriority = this.priorityMap.get(id);
+    if (oldPriority === priority) {
+      return;
+    }
+    if (oldPriority !== undefined) {
+      this.remove(id);
+    }
+    this.tree.insert({ id, priority });
+    this.priorityMap.set(id, priority);
+  }
+
+  pop() {
+    const node = this.tree.max();
+
+    if (!node) {
+      return null;
+    }
+
+    this.tree.removeNode(node);
+
+    const { id } = node.getValue();
+    this.priorityMap.delete(id);
+
+    return id;
+  }
+
+  remove(id: string, priority?: number) {
+    priority ??= this.priorityMap.get(id);
+    if (priority === undefined) {
+      return false;
+    }
+    const removed = this.tree.remove({ id, priority });
+    if (removed) {
+      this.priorityMap.delete(id);
+    }
+
+    return removed;
+  }
+
+  clear() {
+    this.tree.clear();
+    this.priorityMap.clear();
+  }
+
+  updatePriority(id: string, priority: number) {
+    if (this.remove(id)) {
+      this.push(id, priority);
+    }
+  }
+
+  get length() {
+    return this.tree.count;
+  }
+}