14 files changed, 110 insertions, 32 deletions
diff --git a/cli/dts/lib.deno.unstable.d.ts b/cli/dts/lib.deno.unstable.d.ts
index 7ebd80422..3482d1c80 100644
--- a/cli/dts/lib.deno.unstable.d.ts
+++ b/cli/dts/lib.deno.unstable.d.ts
@@ -346,9 +346,14 @@ declare namespace Deno {
     | "f64"
     | "pointer";
 
+  type NativeParameterType =
+    | NativeType
+    | NativeCallbackType;
+
   /** A foreign function as defined by its parameter and result types */
   export interface ForeignFunction<
-    Parameters extends readonly NativeType[] = readonly NativeType[],
+    Parameters extends readonly NativeParameterType[] =
+      readonly NativeParameterType[],
     Result extends NativeType = NativeType,
     NonBlocking extends boolean = boolean,
   > {
@@ -391,11 +396,17 @@ declare namespace Deno {
   type StaticForeignFunctionParameter<T> = T extends "void" ? void
     : T extends StaticNativeNumberType | StaticNativeBigIntType
       ? number | bigint
-    : T extends "pointer" ? Deno.UnsafePointer | Deno.TypedArray | null
+    : T extends "pointer" ? UnsafePointer | TypedArray | null
+    : T extends NativeCallbackType<
+      infer U extends readonly NativeType[],
+      infer V extends NativeParameterType
+    > ? UnsafeCallback<U, V> | UnsafePointer | null
     : unknown;
 
   /** Infers a foreign function parameter list. */
-  type StaticForeignFunctionParameters<T extends readonly NativeType[]> = [
+  type StaticForeignFunctionParameters<
+    T extends readonly NativeParameterType[],
+  > = [
     ...{
       [K in keyof T]: StaticForeignFunctionParameter<T[K]>;
     },
@@ -513,6 +524,83 @@ declare namespace Deno {
     >;
   }
 
+  export interface UnsafeCallbackDefinition<
+    Parameters extends readonly NativeType[] = readonly NativeType[],
+    Result extends NativeParameterType = NativeParameterType,
+  > {
+    parameters: Parameters;
+    result: Result;
+  }
+
+  interface NativeCallbackType<
+    Parameters extends readonly NativeType[] = readonly NativeType[],
+    Result extends NativeParameterType = NativeParameterType,
+  > {
+    readonly function: UnsafeCallbackDefinition<Parameters, Result>;
+  }
+
+  type UnsafeCallbackParameters<T extends readonly NativeType[]> = T extends []
+    ? []
+    : T extends
+      readonly [infer U extends NativeType, ...(infer V extends NativeType[])]
+      ? [
+        UnsafeCallbackParameter<U>,
+        ...UnsafeCallbackParameters<V>,
+      ]
+    : never;
+
+  type UnsafeCallbackParameter<T extends NativeType> = T extends
+    StaticNativeBigIntType ? bigint
+    : T extends StaticNativeNumberType ? number
+    : T extends "pointer" ? UnsafePointer
+    : never;
+
+  type UnsafeCallbackResult<T extends NativeParameterType> = T extends "void"
+    ? void
+    : T extends StaticNativeBigIntType ? number | bigint
+    : T extends StaticNativeNumberType ? number
+    : T extends "pointer" ? UnsafePointer | TypedArray | null
+    : T extends NativeCallbackType<
+      infer U extends readonly NativeType[],
+      infer V extends NativeParameterType
+    > ? UnsafeCallback<U, V> | UnsafePointer | null
+    : never;
+
+  type UnsafeCallbackFunction<
+    Parameters extends readonly NativeType[] = readonly NativeType[],
+    Result extends NativeParameterType = NativeParameterType,
+  > = Result extends NativeParameterType
+    ? Parameters extends readonly [] ? () => UnsafeCallbackResult<Result>
+    : Parameters extends readonly NativeType[] ? (
+      ...args: UnsafeCallbackParameters<Parameters>
+    ) => UnsafeCallbackResult<Result>
+    : never
+    : never;
+
+  /**
+   * **UNSTABLE**: Unsafe and new API, beware!
+   *
+   * An unsafe function pointer for passing JavaScript functions
+   * as C function pointers to ffi calls.
+   *
+   * The function pointer remains valid until the `close()` method is called.
+   */
+  export class UnsafeCallback<
+    Parameters extends readonly NativeType[] = readonly NativeType[],
+    Result extends NativeParameterType = NativeParameterType,
+  > {
+    constructor(
+      definition: UnsafeCallbackDefinition<Parameters, Result>,
+      callback: UnsafeCallbackFunction<Parameters, Result>,
+    );
+
+    pointer: UnsafePointer;
+    definition: UnsafeCallbackDefinition<Parameters, Result>;
+    callback: UnsafeCallbackFunction<Parameters, Result>;
+
+    close(): void;
+  }
+
   /** A dynamic library resource */
   export interface DynamicLibrary<S extends ForeignLibraryInterface> {
     /** All of the registered library along with functions for calling them */
diff --git a/cli/tests/testdata/unstable_ffi_10.js b/cli/tests/testdata/unstable_ffi_10.js
index c7cafd3ea..e8fc9b3f0 100644
--- a/cli/tests/testdata/unstable_ffi_10.js
+++ b/cli/tests/testdata/unstable_ffi_10.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_i16", [0, 0]);
+Deno.core.opSync("op_ffi_read_i16", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_11.js b/cli/tests/testdata/unstable_ffi_11.js
index 37bd75cc9..77c86109a 100644
--- a/cli/tests/testdata/unstable_ffi_11.js
+++ b/cli/tests/testdata/unstable_ffi_11.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_u32", [0, 0]);
+Deno.core.opSync("op_ffi_read_u32", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_12.js b/cli/tests/testdata/unstable_ffi_12.js
index b05f92d39..65934a82f 100644
--- a/cli/tests/testdata/unstable_ffi_12.js
+++ b/cli/tests/testdata/unstable_ffi_12.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_i32", [0, 0]);
+Deno.core.opSync("op_ffi_read_i32", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_13.js b/cli/tests/testdata/unstable_ffi_13.js
index a83b8dc18..0ab43781b 100644
--- a/cli/tests/testdata/unstable_ffi_13.js
+++ b/cli/tests/testdata/unstable_ffi_13.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_u64", [0, 0]);
+Deno.core.opSync("op_ffi_read_u64", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_14.js b/cli/tests/testdata/unstable_ffi_14.js
index b39b99da5..b65a50a20 100644
--- a/cli/tests/testdata/unstable_ffi_14.js
+++ b/cli/tests/testdata/unstable_ffi_14.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_f32", [0, 0]);
+Deno.core.opSync("op_ffi_read_f32", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_15.js b/cli/tests/testdata/unstable_ffi_15.js
index afd49b722..de9f29168 100644
--- a/cli/tests/testdata/unstable_ffi_15.js
+++ b/cli/tests/testdata/unstable_ffi_15.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_f64", [0, 0]);
+Deno.core.opSync("op_ffi_read_f64", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_2.js b/cli/tests/testdata/unstable_ffi_2.js
index de392fa7d..fe3d9d709 100644
--- a/cli/tests/testdata/unstable_ffi_2.js
+++ b/cli/tests/testdata/unstable_ffi_2.js
@@ -1,10 +1,5 @@
-Deno.core.opSync("op_ffi_call_ptr", {
-  pointer: [0, 0],
-  def: {
-    name: null,
-    parameters: [],
-    result: "void",
-  },
+Deno.core.opSync("op_ffi_call_ptr", 0n, {
+  name: null,
   parameters: [],
-  buffers: [],
-});
+  result: "void",
+}, []);
diff --git a/cli/tests/testdata/unstable_ffi_3.js b/cli/tests/testdata/unstable_ffi_3.js
index 4924d9d67..a8f7f4180 100644
--- a/cli/tests/testdata/unstable_ffi_3.js
+++ b/cli/tests/testdata/unstable_ffi_3.js
@@ -1,10 +1,5 @@
-Deno.core.opAsync("op_ffi_call_ptr_nonblocking", {
-  pointer: [0, 0],
-  def: {
-    name: null,
-    parameters: [],
-    result: "void",
-  },
+Deno.core.opAsync("op_ffi_call_ptr_nonblocking", 0n, {
+  name: null,
   parameters: [],
-  buffers: [],
-});
+  result: "void",
+}, []);
diff --git a/cli/tests/testdata/unstable_ffi_5.js b/cli/tests/testdata/unstable_ffi_5.js
index 447ff5842..dc494023d 100644
--- a/cli/tests/testdata/unstable_ffi_5.js
+++ b/cli/tests/testdata/unstable_ffi_5.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_buf_copy_into", [[0, 0], new Uint8Array(0), 0]);
+Deno.core.opSync("op_ffi_buf_copy_into", 0n, new Uint8Array(0), 0);
diff --git a/cli/tests/testdata/unstable_ffi_6.js b/cli/tests/testdata/unstable_ffi_6.js
index cc791b8f0..c66681225 100644
--- a/cli/tests/testdata/unstable_ffi_6.js
+++ b/cli/tests/testdata/unstable_ffi_6.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_cstr_read", [0, 0]);
+Deno.core.opSync("op_ffi_cstr_read", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_7.js b/cli/tests/testdata/unstable_ffi_7.js
index 02ef455ee..a0c27a71c 100644
--- a/cli/tests/testdata/unstable_ffi_7.js
+++ b/cli/tests/testdata/unstable_ffi_7.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_u8", [0, 0]);
+Deno.core.opSync("op_ffi_read_u8", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_8.js b/cli/tests/testdata/unstable_ffi_8.js
index d250c9f21..7c51f8aa3 100644
--- a/cli/tests/testdata/unstable_ffi_8.js
+++ b/cli/tests/testdata/unstable_ffi_8.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_i8", [0, 0]);
+Deno.core.opSync("op_ffi_read_i8", 0n);
diff --git a/cli/tests/testdata/unstable_ffi_9.js b/cli/tests/testdata/unstable_ffi_9.js
index f21a4cdbf..7798e4d2c 100644
--- a/cli/tests/testdata/unstable_ffi_9.js
+++ b/cli/tests/testdata/unstable_ffi_9.js
@@ -1 +1 @@
-Deno.core.opSync("op_ffi_read_u16", [0, 0]);
+Deno.core.opSync("op_ffi_read_u16", 0n);