청크 업로드 성능 개선 및 네트워크 속도를 더 정확하게 측정하도록 개선

src/lib/utils/concurrency/HybridPromise.ts

@@ -0,0 +1,93 @@
+type MaybePromise<T> = T | Promise<T> | HybridPromise<T>;
+
+type HybridPromiseState<T> =
+  | { mode: "sync"; status: "fulfilled"; value: T }
+  | { mode: "sync"; status: "rejected"; reason: unknown }
+  | { mode: "async"; promise: Promise<T> };
+
+export class HybridPromise<T> implements PromiseLike<T> {
+  private isConsumed = false;
+
+  private constructor(private readonly state: HybridPromiseState<T>) {
+    if (state.mode === "sync" && state.status === "rejected") {
+      queueMicrotask(() => {
+        if (!this.isConsumed) {
+          throw state.reason;
+        }
+      });
+    }
+  }
+
+  isSync(): boolean {
+    return this.state.mode === "sync";
+  }
+
+  toPromise(): Promise<T> {
+    this.isConsumed = true;
+
+    if (this.state.mode === "async") return this.state.promise;
+    return this.state.status === "fulfilled"
+      ? Promise.resolve(this.state.value)
+      : Promise.reject(this.state.reason);
+  }
+
+  static resolve<T>(value: MaybePromise<T>): HybridPromise<T> {
+    if (value instanceof HybridPromise) return value;
+    return new HybridPromise(
+      value instanceof Promise
+        ? { mode: "async", promise: value }
+        : { mode: "sync", status: "fulfilled", value },
+    );
+  }
+
+  static reject<T = never>(reason?: unknown): HybridPromise<T> {
+    return new HybridPromise({ mode: "sync", status: "rejected", reason });
+  }
+
+  then<TResult1 = T, TResult2 = never>(
+    onfulfilled?: ((value: T) => MaybePromise<TResult1>) | null | undefined,
+    onrejected?: ((reason: unknown) => MaybePromise<TResult2>) | null | undefined,
+  ): HybridPromise<TResult1 | TResult2> {
+    this.isConsumed = true;
+
+    if (this.state.mode === "async") {
+      return new HybridPromise({
+        mode: "async",
+        promise: this.state.promise.then(onfulfilled, onrejected) as any,
+      });
+    }
+
+    try {
+      if (this.state.status === "fulfilled") {
+        if (!onfulfilled) return HybridPromise.resolve(this.state.value as any);
+        return HybridPromise.resolve(onfulfilled(this.state.value));
+      } else {
+        if (!onrejected) return HybridPromise.reject(this.state.reason);
+        return HybridPromise.resolve(onrejected(this.state.reason));
+      }
+    } catch (e) {
+      return HybridPromise.reject(e);
+    }
+  }
+
+  catch<TResult = never>(
+    onrejected?: ((reason: unknown) => MaybePromise<TResult>) | null | undefined,
+  ): HybridPromise<T | TResult> {
+    return this.then<T, TResult>(null, onrejected);
+  }
+
+  finally(onfinally?: (() => void) | null | undefined): HybridPromise<T> {
+    this.isConsumed = true;
+
+    if (this.state.mode === "async") {
+      return new HybridPromise({ mode: "async", promise: this.state.promise.finally(onfinally) });
+    }
+
+    try {
+      onfinally?.();
+      return new HybridPromise(this.state);
+    } catch (e) {
+      return HybridPromise.reject(e);
+    }
+  }
+}