From 781792f9e557ea263ce1c54da91abc1818c42a54 Mon Sep 17 00:00:00 2001
From: cm-ayf <cm.ayf2734@gmail.com>
Date: Sun, 26 May 2024 13:07:03 +0900
Subject: [PATCH] use built-in cache in readable (#38)

---
 lib/index.js  | 36 +++++++++---------------------------
 test/index.js |  9 +++++----
 2 files changed, 14 insertions(+), 31 deletions(-)

diff --git a/lib/index.js b/lib/index.js
index 6e228f7..3797245 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -19,6 +19,8 @@ exports.Application = Application;
 const { version: OM_SYRINX_VERSION } = require("../package.json");
 exports.OM_SYRINX_VERSION = OM_SYRINX_VERSION;
 
+const { setTimeout } = require("node:timers/promises");
+
 class SyrinxStream extends Readable {
   /**
    * @param {import("./native").Syrinx} syrinx
@@ -43,21 +45,6 @@ class SyrinxStream extends Readable {
      * @private
      */
     this._option = option;
-    /**
-     * @type {Buffer[]}
-     * @private
-     */
-    this._cache = [];
-    /**
-     * @type {number}
-     * @private
-     */
-    this._waiting = 0;
-    /**
-     * @type {boolean}
-     * @private
-     */
-    this._ended = false;
   }
 
   /**
@@ -74,22 +61,17 @@ class SyrinxStream extends Readable {
     callback(error);
 
     await synthesizer?.synthesize((err, result) => {
-      if (err) return this.emit("error", err);
-      if (this._waiting > 0) {
-        this._waiting--;
-        this.push(result);
-      } else this._cache.push(result);
+      if (err) this.emit("error", err);
+      else this.push(result);
     });
 
-    this._ended = true;
+    // The last push sometimes occurs after the Promise resolution,
+    // so we need to make sure that the last push occurs before the stream ends.
+    await setTimeout();
+    this.push(null);
   }
 
-  _read() {
-    const cache = this._cache.shift();
-    if (cache) this.push(cache);
-    else if (this._ended) this.push(null);
-    else this._waiting++;
-  }
+  _read() {}
 }
 
 class Syrinx {
diff --git a/test/index.js b/test/index.js
index 6413e18..a42dcd3 100644
--- a/test/index.js
+++ b/test/index.js
@@ -79,15 +79,16 @@ async function fetchAndExtract(url, path) {
  * @param {Syrinx} syrinx
  * @param {string} inputText
  * @param {import("../lib").SynthesisOption} option
+ * @param {boolean} [wait]
  * @returns {Promise<Buffer[]>}
  */
-async function synthesize(syrinx, inputText, option) {
+async function synthesize(syrinx, inputText, option, wait = false) {
   const stream = syrinx.synthesize(inputText, option);
   /** @type {Buffer[]} */
   const result = [];
   for await (const item of stream) {
     result.push(item);
-    await setTimeout(20);
+    if (wait) await setTimeout(20);
   }
   return result;
 }
@@ -130,7 +131,7 @@ describe("synthesis", () => {
       encoder: { type: EncoderType.Raw },
     });
 
-    const bonsai = await synthesize(pcm, "盆栽", {});
+    const bonsai = await synthesize(pcm, "盆栽", {}, true);
     await checksum(
       Buffer.concat(bonsai),
       "36050aef60896f56bbfe59868a3f57b6bbc5b147",
@@ -160,7 +161,7 @@ describe("synthesis", () => {
       encoder: { type: EncoderType.Opus },
     });
 
-    const bonsai = await synthesize(opus, "盆栽", {});
+    const bonsai = await synthesize(opus, "盆栽", {}, true);
     assert.strictEqual(bonsai.length, 78);
 
     const bonsaiDecoded = decoder.decodeFrames(bonsai);