fix(napi): BigInt related APIs (#19174)

Doesn't make the API bullet-proof and there are some TODOs left,
but greatly improves the situation. Tests were ported from Node.js.

Closes https://github.com/denoland/deno/issues/18276.

cli/napi/js_native_api.rs

@@ -200,8 +200,8 @@ fn napi_create_bigint_uint64(
 fn napi_create_bigint_words(
   env: *mut Env,
   sign_bit: bool,
-  words: *const u64,
   word_count: usize,
+  words: *const u64,
   result: *mut napi_value,
 ) -> Result {
   check_env!(env);
@@ -950,12 +950,17 @@ fn napi_get_value_bigint_int64(
   env: *mut Env,
   value: napi_value,
   result: *mut i64,
+  lossless: *mut bool,
 ) -> Result {
   check_env!(env);
   let env = unsafe { &mut *env };
   let value = napi_value_unchecked(value);
   let bigint = value.to_big_int(&mut env.scope()).unwrap();
-  *result = bigint.i64_value().0;
+  let (result_, lossless_) = bigint.i64_value();
+  *result = result_;
+  *lossless = lossless_;
+  // TODO(bartlomieju):
+  // napi_clear_last_error()
   Ok(())
 }
 
@@ -964,12 +969,17 @@ fn napi_get_value_bigint_uint64(
   env: *mut Env,
   value: napi_value,
   result: *mut u64,
+  lossless: *mut bool,
 ) -> Result {
   check_env!(env);
   let env = unsafe { &mut *env };
   let value = napi_value_unchecked(value);
   let bigint = value.to_big_int(&mut env.scope()).unwrap();
-  *result = bigint.u64_value().0;
+  let (result_, lossless_) = bigint.u64_value();
+  *result = result_;
+  *lossless = lossless_;
+  // TODO(bartlomieju):
+  // napi_clear_last_error()
   Ok(())
 }
 
@@ -978,24 +988,36 @@ fn napi_get_value_bigint_words(
   env: *mut Env,
   value: napi_value,
   sign_bit: *mut i32,
-  size: *mut usize,
-  out_words: *mut u64,
+  word_count: *mut usize,
+  words: *mut u64,
 ) -> Result {
   check_env!(env);
+  // TODO(bartlomieju):
+  // check_arg!(env, value);
+  check_arg!(env, word_count);
   let env = unsafe { &mut *env };
 
   let value = napi_value_unchecked(value);
-  let bigint = value.to_big_int(&mut env.scope()).unwrap();
+  let big = match value.to_big_int(&mut env.scope()) {
+    Some(b) => b,
+    None => return Err(Error::BigIntExpected),
+  };
+  let word_count_int;
 
-  let out_words = std::slice::from_raw_parts_mut(out_words, *size);
-  let mut words = Vec::with_capacity(bigint.word_count());
-  let (sign, _) = bigint.to_words_array(words.as_mut_slice());
-  *sign_bit = sign as i32;
-
-  for (i, word) in out_words.iter_mut().enumerate() {
-    *word = words[i];
+  if sign_bit.is_null() && words.is_null() {
+    word_count_int = big.word_count();
+  } else {
+    check_arg!(env, sign_bit);
+    check_arg!(env, words);
+    let out_words = std::slice::from_raw_parts_mut(words, *word_count);
+    let (sign, slice_) = big.to_words_array(out_words);
+    word_count_int = slice_.len();
+    *sign_bit = sign as i32;
   }
 
+  *word_count = word_count_int;
+  // TODO(bartlomieju):
+  // napi_clear_last_error()
   Ok(())
 }
 

test_napi/bigint_test.js

@@ -0,0 +1,63 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+import { assertEquals, assertThrows, loadTestLibrary } from "./common.js";
+
+const bi = loadTestLibrary();
+
+Deno.test("cases", function () {
+  const cases = [
+    0n,
+    -0n,
+    1n,
+    -1n,
+    100n,
+    2121n,
+    -1233n,
+    986583n,
+    -976675n,
+    98765432213456789876546896323445679887645323232436587988766545658n,
+    -4350987086545760976737453646576078997096876957864353245245769809n,
+  ];
+
+  for (const num of cases) {
+    if (num > -(2n ** 63n) && num < 2n ** 63n) {
+      assertEquals(bi.testInt64(num), num);
+      assertEquals(bi.isLossless(num, true), true);
+    } else {
+      assertEquals(bi.isLossless(num, true), false);
+    }
+
+    if (num >= 0 && num < 2n ** 64n) {
+      assertEquals(bi.testUint64(num), num);
+      assertEquals(bi.isLossless(num, false), true);
+    } else {
+      assertEquals(bi.isLossless(num, false), false);
+    }
+
+    assertEquals(bi.testWords(num), num);
+  }
+});
+
+Deno.test(
+  // TODO(bartlomieju): fix this test
+  { ignore: true },
+  function tooBigBigInt() {
+    assertThrows(
+      () => bi.createTooBigBigInt(),
+      Error,
+      "Invalid argument",
+    );
+  },
+);
+
+Deno.test(
+  // TODO(bartlomieju): fix this test
+  { ignore: true },
+  function exceptionForwarding() {
+    assertThrows(
+      () => bi.makeBigIntWordsThrow(),
+      Error,
+      "Maximum BigInt size exceeded",
+    );
+  },
+);

test_napi/src/bigint.rs

@@ -0,0 +1,205 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use crate::assert_napi_ok;
+use crate::cstr;
+use crate::napi_get_callback_info;
+use crate::napi_new_property;
+use napi_sys::Status::napi_pending_exception;
+use napi_sys::ValueType::napi_bigint;
+use napi_sys::*;
+use std::ptr;
+
+extern "C" fn is_lossless(
+  env: napi_env,
+  info: napi_callback_info,
+) -> napi_value {
+  let (args, argc, _) = napi_get_callback_info!(env, info, 2);
+  assert_eq!(argc, 2);
+
+  let mut is_signed = false;
+  assert_napi_ok!(napi_get_value_bool(env, args[1], &mut is_signed));
+
+  let mut lossless = false;
+
+  if is_signed {
+    let mut input: i64 = 0;
+    assert_napi_ok!(napi_get_value_bigint_int64(
+      env,
+      args[0],
+      &mut input,
+      &mut lossless
+    ));
+  } else {
+    let mut input: u64 = 0;
+    assert_napi_ok!(napi_get_value_bigint_uint64(
+      env,
+      args[0],
+      &mut input,
+      &mut lossless
+    ));
+  }
+
+  let mut output: napi_value = ptr::null_mut();
+  assert_napi_ok!(napi_get_boolean(env, lossless, &mut output));
+
+  output
+}
+
+extern "C" fn test_int64(
+  env: napi_env,
+  info: napi_callback_info,
+) -> napi_value {
+  let (args, _argc, _) = napi_get_callback_info!(env, info, 2);
+
+  let mut ty = -1;
+  assert_napi_ok!(napi_typeof(env, args[0], &mut ty));
+  assert_eq!(ty, napi_bigint);
+
+  let mut input: i64 = 0;
+  let mut lossless = false;
+  assert_napi_ok!(napi_get_value_bigint_int64(
+    env,
+    args[0],
+    &mut input,
+    &mut lossless
+  ));
+
+  let mut output: napi_value = ptr::null_mut();
+  assert_napi_ok!(napi_create_bigint_int64(env, input, &mut output));
+
+  output
+}
+
+extern "C" fn test_uint64(
+  env: napi_env,
+  info: napi_callback_info,
+) -> napi_value {
+  let (args, _argc, _) = napi_get_callback_info!(env, info, 2);
+
+  let mut ty = -1;
+  assert_napi_ok!(napi_typeof(env, args[0], &mut ty));
+  assert_eq!(ty, napi_bigint);
+
+  let mut input: u64 = 0;
+  let mut lossless = false;
+  assert_napi_ok!(napi_get_value_bigint_uint64(
+    env,
+    args[0],
+    &mut input,
+    &mut lossless
+  ));
+
+  let mut output: napi_value = ptr::null_mut();
+  assert_napi_ok!(napi_create_bigint_uint64(env, input, &mut output));
+
+  output
+}
+
+extern "C" fn test_words(
+  env: napi_env,
+  info: napi_callback_info,
+) -> napi_value {
+  let (args, _argc, _) = napi_get_callback_info!(env, info, 1);
+
+  let mut ty = -1;
+  assert_napi_ok!(napi_typeof(env, args[0], &mut ty));
+  assert_eq!(ty, napi_bigint);
+
+  let mut expected_work_count = 0;
+  assert_napi_ok!(napi_get_value_bigint_words(
+    env,
+    args[0],
+    ptr::null_mut(),
+    &mut expected_work_count,
+    ptr::null_mut()
+  ));
+
+  let mut sign_bit = 0;
+  let mut word_count: usize = 10;
+  let mut words: Vec<u64> = Vec::with_capacity(10);
+
+  assert_napi_ok!(napi_get_value_bigint_words(
+    env,
+    args[0],
+    &mut sign_bit,
+    &mut word_count,
+    words.as_mut_ptr(),
+  ));
+
+  assert_eq!(word_count, expected_work_count);
+  let mut output: napi_value = ptr::null_mut();
+
+  assert_napi_ok!(napi_create_bigint_words(
+    env,
+    sign_bit,
+    word_count,
+    words.as_ptr(),
+    &mut output,
+  ));
+  output
+}
+
+extern "C" fn create_too_big_big_int(
+  env: napi_env,
+  _info: napi_callback_info,
+) -> napi_value {
+  let sign_bit = 0;
+  let word_count = usize::MAX;
+  let words: Vec<u64> = Vec::with_capacity(10);
+
+  let mut output: napi_value = ptr::null_mut();
+  let result = unsafe {
+    napi_create_bigint_words(
+      env,
+      sign_bit,
+      word_count,
+      words.as_ptr(),
+      &mut output,
+    )
+  };
+  assert_eq!(result, 1);
+
+  output
+}
+
+extern "C" fn make_big_int_words_throw(
+  env: napi_env,
+  _info: napi_callback_info,
+) -> napi_value {
+  let words: Vec<u64> = Vec::with_capacity(10);
+  let mut output = ptr::null_mut();
+
+  let status = unsafe {
+    napi_create_bigint_words(env, 0, usize::MAX, words.as_ptr(), &mut output)
+  };
+
+  if status != napi_pending_exception {
+    unsafe {
+      napi_throw_error(
+        env,
+        ptr::null_mut(),
+        cstr!("Expected status 'napi_pending_exception'"),
+      )
+    };
+  }
+
+  ptr::null_mut()
+}
+
+pub fn init(env: napi_env, exports: napi_value) {
+  let properties = &[
+    napi_new_property!(env, "isLossless", is_lossless),
+    napi_new_property!(env, "testInt64", test_int64),
+    napi_new_property!(env, "testUint64", test_uint64),
+    napi_new_property!(env, "testWords", test_words),
+    napi_new_property!(env, "createTooBigBigInt", create_too_big_big_int),
+    napi_new_property!(env, "makeBigIntWordsThrow", make_big_int_words_throw),
+  ];
+
+  assert_napi_ok!(napi_define_properties(
+    env,
+    exports,
+    properties.len(),
+    properties.as_ptr()
+  ));
+}

test_napi/src/lib.rs

@@ -9,6 +9,7 @@ use napi_sys::*;
 pub mod array;
 pub mod arraybuffer;
 pub mod r#async;
+pub mod bigint;
 pub mod callback;
 pub mod coerce;
 pub mod date;
@@ -156,6 +157,7 @@ unsafe extern "C" fn napi_register_module_v1(
   date::init(env, exports);
   tsfn::init(env, exports);
   mem::init(env, exports);
+  bigint::init(env, exports);
 
   init_cleanup_hook(env, exports);
 

test_napi/tests/napi_tests.rs

@@ -26,6 +26,7 @@ fn napi_tests() {
 
   let output = deno_cmd()
     .current_dir(test_util::napi_tests_path())
+    .env("RUST_BACKTRACE", "1")
     .arg("test")
     .arg("--allow-read")
     .arg("--allow-env")
@@ -39,6 +40,7 @@ fn napi_tests() {
   let stderr = std::str::from_utf8(&output.stderr).unwrap();
 
   if !output.status.success() {
+    eprintln!("exit code {:?}", output.status.code());
     println!("stdout {stdout}");
     println!("stderr {stderr}");
   }