fix(ext/ffi): use anybuffer for op_ffi_ptr_of (#20820)

Fixes #20817

cli/tests/unit/ffi_test.ts

@@ -1,6 +1,6 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
-import { assertThrows } from "./test_util.ts";
+import { assertEquals, assertThrows } from "./test_util.ts";
 
 Deno.test({ permissions: { ffi: true } }, function dlopenInvalidArguments() {
   const filename = "/usr/lib/libc.so.6";
@@ -77,3 +77,24 @@ Deno.test({ permissions: { ffi: false } }, function ffiPermissionDenied() {
     ptrView.getFloat64();
   }, Deno.errors.PermissionDenied);
 });
+
+Deno.test({ permissions: { ffi: true } }, function pointerOf() {
+  const buffer = new ArrayBuffer(1024);
+  const baseAddress = Deno.UnsafePointer.value(Deno.UnsafePointer.of(buffer));
+  const uint8Address = Deno.UnsafePointer.value(
+    Deno.UnsafePointer.of(new Uint8Array(buffer)),
+  );
+  assertEquals(baseAddress, uint8Address);
+  const float64Address = Deno.UnsafePointer.value(
+    Deno.UnsafePointer.of(new Float64Array(buffer)),
+  );
+  assertEquals(baseAddress, float64Address);
+  const uint8AddressOffset = Deno.UnsafePointer.value(
+    Deno.UnsafePointer.of(new Uint8Array(buffer, 100)),
+  );
+  assertEquals(Number(baseAddress) + 100, uint8AddressOffset);
+  const float64AddressOffset = Deno.UnsafePointer.value(
+    Deno.UnsafePointer.of(new Float64Array(buffer, 80)),
+  );
+  assertEquals(Number(baseAddress) + 80, float64AddressOffset);
+});

ext/ffi/repr.rs

@@ -47,7 +47,7 @@ where
 #[op2(fast)]
 pub fn op_ffi_ptr_of<FP>(
   state: &mut OpState,
-  #[buffer] buf: *const u8,
+  #[anybuffer] buf: *const u8,
 ) -> Result<*mut c_void, AnyError>
 where
   FP: FfiPermissions + 'static,