Implement WebAssembly.Memory#grow()

.changeset/gentle-garlics-fry.md

@@ -0,0 +1,5 @@
+---
+'nxjs-runtime': patch
+---
+
+Implement `WebAssembly.Memory#grow()`

apps/tests/src/wasm.ts

@@ -230,33 +230,42 @@ test('grow.wasm', async () => {
 
 	assert.equal(WebAssembly.Module.exports(module), [
 		{ name: 'grow', kind: 'function' },
+		{ name: 'getPageCount', kind: 'function' },
 		{ name: 'mem', kind: 'memory' },
 	]);
 
 	const grow = instance.exports.grow as Function;
+	const getPageCount = instance.exports.getPageCount as Function;
 	const mem = instance.exports.mem as WebAssembly.Memory;
 	assert.instance(mem, WebAssembly.Memory);
 
 	const buf = mem.buffer;
 	assert.equal(buf.byteLength, 65536, 'Initially, page size = 1');
+	assert.equal(getPageCount(), 1);
 	// TODO: make work
 	//assert.ok(buf === mem.buffer, 'Same size, same instance (size = 1)');
 
 	grow();
 	const buf2 = mem.buffer;
 	assert.equal(buf2.byteLength, 65536 * 2, 'Page size = 2');
+	assert.equal(getPageCount(), 2);
 	assert.ok(buf !== buf2, 'Different size, different instance (size = 2)');
 	// TODO: make work
 	//assert.ok(buf2 === mem.buffer, 'Same size, same instance (size = 2)');
 
 	grow();
 	const buf3 = mem.buffer;
 	assert.equal(buf3.byteLength, 65536 * 3, 'Page size = 3');
+	assert.equal(getPageCount(), 3);
 	assert.ok(buf2 !== buf3, 'Different size, different instance (size = 3)');
 	// TODO: make work
 	//assert.ok(buf3 === mem.buffer, 'Same size, same instance (size = 3)');
 
-	// TODO: `mem.grow(1)` test, once that function is implemented
+	// Now using `mem.grow()` from the JavaScript side
+	mem.grow(2);
+	const buf4 = mem.buffer;
+	assert.equal(buf4.byteLength, 65536 * 5, 'Page size = 5');
+	assert.equal(getPageCount(), 5);
 });
 
 test('compute.wasm', async () => {

packages/runtime/src/wasm.ts

@@ -237,9 +237,8 @@ export class Memory implements WebAssembly.Memory {
 	declare readonly buffer: ArrayBuffer;
 
 	/** [MDN Reference](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/Memory/grow) */
-	grow(delta: number): number {
-		throw new Error('Method not implemented.');
-	}
+	// @ts-expect-error This is a native function
+	grow(delta: number): number {}
 }
 $.wasmInitMemory(Memory);
 

source/wasm.c

@@ -982,6 +982,56 @@ static JSValue nx_wasm_memory_buffer_get(JSContext *ctx, JSValueConst this_val,
     return buf;
 }
 
+// `Memory#grow()` function
+static JSValue nx_wasm_memory_grow(JSContext *ctx, JSValueConst this_val, int argc, JSValueConst *argv)
+{
+    nx_wasm_memory_t *data = nx_wasm_memory_get(ctx, this_val);
+    if (!data)
+        return JS_EXCEPTION;
+
+    IM3Memory memory = data->mem;
+    if (!memory)
+    {
+        JS_ThrowTypeError(ctx, "Memory not set");
+        return JS_EXCEPTION;
+    }
+
+    M3MemoryHeader *mallocated = memory->mallocated;
+    if (!mallocated)
+    {
+        JS_ThrowTypeError(ctx, "Memory not allocated");
+        return JS_EXCEPTION;
+    }
+
+    i32 numPagesToGrow;
+    if (JS_ToInt32(ctx, &numPagesToGrow, argv[0]))
+        return JS_EXCEPTION;
+
+    if (numPagesToGrow < 0)
+    {
+        JS_ThrowTypeError(ctx, "WebAssembly.Memory.grow(): Argument 0 must be non-negative");
+        return JS_EXCEPTION;
+    }
+
+    JSValue prevSize = JS_NewUint32(ctx, memory->numPages);
+
+    if (numPagesToGrow > 0)
+    {
+        IM3Runtime runtime = m3MemRuntime(mallocated);
+        if (!runtime)
+        {
+            JS_ThrowTypeError(ctx, "WebAssembly.Memory.grow(): Memory not bound to an instance");
+            return JS_EXCEPTION;
+        }
+        u32 requiredPages = memory->numPages + numPagesToGrow;
+        M3Result r = ResizeMemory(runtime, requiredPages);
+        if (r)
+            return nx_throw_wasm_error(ctx, "RuntimeError", r);
+    }
+
+    return prevSize;
+}
+
 // `Table#get()` function
 static JSValue nx_wasm_table_get_fn(JSContext *ctx, JSValueConst this_val, int argc, JSValueConst *argv)
 {
@@ -1034,6 +1084,7 @@ static JSValue nx_wasm_init_memory_class(JSContext *ctx, JSValueConst this_val,
     JSAtom atom;
     JSValue proto = JS_GetPropertyStr(ctx, argv[0], "prototype");
     NX_DEF_GETTER(proto, "buffer", nx_wasm_memory_buffer_get);
+    NX_DEF_FUNC(proto, "grow", nx_wasm_memory_grow, 1);
     JS_FreeValue(ctx, proto);
     return JS_UNDEFINED;
 }