From 7f018fc74a4119a23b500980fa1a5ba76b397f91 Mon Sep 17 00:00:00 2001
From: Grischa Erbe <46897060+grischaerbe@users.noreply.github.com>
Date: Fri, 22 Jul 2022 23:25:25 +0200
Subject: [PATCH] Added checks to init() in compatibility module to catch
 multiple calls to init()

---
 rapier-compat/src2d/init.ts | 29 ++++++++++++++++++++++++++++-
 rapier-compat/src3d/init.ts | 29 ++++++++++++++++++++++++++++-
 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/rapier-compat/src2d/init.ts b/rapier-compat/src2d/init.ts
index 4a21ed03..6cb24f24 100644
--- a/rapier-compat/src2d/init.ts
+++ b/rapier-compat/src2d/init.ts
@@ -3,10 +3,37 @@ import wasmBase64 from "../pkg2d/rapier_wasm2d_bg.wasm";
 import wasmInit from "../pkg2d/rapier_wasm2d";
 import base64 from "base64-js";
 
+/**
+ * Flag to check if RAPIER has already been initialized
+ * or is currently being initialized.
+ */
+let initialized = false;
+
+/**
+ * If init has already been called before but initialization
+ * is not done yet, the unresolved promise is returned.
+ */
+let initPromise: ReturnType<typeof wasmInit> | undefined = undefined;
+
 /**
  * Initializes RAPIER.
  * Has to be called and awaited before using any library methods.
  */
 export async function init() {
-    await wasmInit(base64.toByteArray(wasmBase64 as unknown as string).buffer);
+    // return if RAPIER has been initialized
+    if (initialized) return;
+
+    // return the unresolve promise if RAPIER is currently initializing
+    if (initPromise) return initPromise;
+
+    // init and assign promise
+    initPromise = wasmInit(
+        base64.toByteArray(wasmBase64 as unknown as string).buffer,
+    );
+
+    // await initialization
+    await initPromise;
+
+    // set initialized flag
+    initialized = true;
 }
diff --git a/rapier-compat/src3d/init.ts b/rapier-compat/src3d/init.ts
index 0ad05f63..8a438257 100644
--- a/rapier-compat/src3d/init.ts
+++ b/rapier-compat/src3d/init.ts
@@ -3,10 +3,37 @@ import wasmBase64 from "../pkg3d/rapier_wasm3d_bg.wasm";
 import wasmInit from "../pkg3d/rapier_wasm3d";
 import base64 from "base64-js";
 
+/**
+ * Flag to check if RAPIER has already been initialized
+ * or is currently being initialized.
+ */
+let initialized = false;
+
+/**
+ * If init has already been called before but initialization
+ * is not done yet, the unresolved promise is returned.
+ */
+let initPromise: ReturnType<typeof wasmInit> | undefined = undefined;
+
 /**
  * Initializes RAPIER.
  * Has to be called and awaited before using any library methods.
  */
 export async function init() {
-    await wasmInit(base64.toByteArray(wasmBase64 as unknown as string).buffer);
+    // return if RAPIER has been initialized
+    if (initialized) return;
+
+    // return the unresolve promise if RAPIER is currently initializing
+    if (initPromise) return initPromise;
+
+    // init and assign promise
+    initPromise = wasmInit(
+        base64.toByteArray(wasmBase64 as unknown as string).buffer,
+    );
+
+    // await initialization
+    await initPromise;
+
+    // set initialized flag
+    initialized = true;
 }