1 files changed, 41 insertions, 0 deletions
diff --git a/ext/wasm/api/pre-js.js b/ext/wasm/api/pre-js.js
new file mode 100644
index 000000000..502ecf348
--- /dev/null
+++ b/ext/wasm/api/pre-js.js
@@ -0,0 +1,41 @@
+Module['locateFile'] = function(path, prefix) {
+  return prefix + path;
+};
+
+/**
+   Bug warning: this xInstantiateWasm bit must remain disabled
+   until this bug is resolved or wasmfs won't work:
+
+   https://github.com/emscripten-core/emscripten/issues/17951
+*/
+const xInstantiateWasm = 1
+      ? 'emscripten-bug-17951'
+      : 'instantiateWasm';
+Module[xInstantiateWasm] = function callee(imports,onSuccess){
+  imports.env.foo = function(){};
+  console.warn("instantiateWasm() uri =",callee.uri, self.location.href);
+  const wfetch = ()=>fetch(callee.uri, {credentials: 'same-origin'});
+  const loadWasm = WebAssembly.instantiateStreaming
+        ? async ()=>{
+          return WebAssembly.instantiateStreaming(wfetch(), imports)
+            .then((arg)=>onSuccess(arg.instance, arg.module));
+        }
+        : async ()=>{ // Safari < v15
+          return wfetch()
+            .then(response => response.arrayBuffer())
+            .then(bytes => WebAssembly.instantiate(bytes, imports))
+            .then((arg)=>onSuccess(arg.instance, arg.module));
+        };
+  loadWasm();
+  return {};
+};
+/*
+  It is literally impossible to reliably get the name of _this_ script
+  at runtime, so impossible to derive X.wasm from script name
+  X.js. Thus we need, at build-time, to redefine
+  Module[xInstantiateWasm].uri by appending it to a build-specific
+  copy of this file with the name of the wasm file. This is apparently
+  why Emscripten hard-codes the name of the wasm file into their glue
+  scripts.
+*/
+Module[xInstantiateWasm].uri = 'sqlite3.wasm';