ffi: accept safe integer numbers for 64-bit arguments

[HoonDongKang]

Summary

Accept safe integer numbers for int64/uint64 arguments alongside bigint values, allowing buffer lengths to be passed without explicit BigInt() conversions.

-functions.sum_buffer(bytes, BigInt(bytes.byteLength));
+functions.sum_buffer(bytes, bytes.byteLength);

Changes

• Accept safe integer numbers for int64 and non-negative safe integer numbers for uint64.
• Validate and convert arguments across Fast API, SharedBuffer, and generic C++ conversion paths.
• Preserve existing bigint range checks and bigint return values.
• Document the accepted number ranges.

Tests

The tests check that number and bigint arguments produce the same results, including when used together. A new single-argument test covers Fast API conversion before and after requesting V8 optimization.

Separate nine-argument tests exercise SharedBuffer conversion and generic fallback. Both check Number and BigInt boundaries, invalid inputs, and error messages.

// SharedBuffer: validates and converts the integer in JavaScript.
functions.passthrough_i64_9(0n, value, ...zeros);

// Generic fallback: validates and converts the integer in C++.
functions.passthrough_i64_9(buffer, value, ...zeros);

Validation

54 tests passed across the following files. Local lint and whitespace checks also passed.

./node --test \
  test/ffi/test-ffi-calls.js \
  test/ffi/test-ffi-fast-integer-validation.js \
  test/ffi/test-ffi-shared-buffer.js


ℹ tests 54
ℹ suites 0
ℹ pass 54
ℹ fail 0
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 934.82625

Refs: #66198
Assisted-by: Codex:Astra-medium

[nodejs-github-bot]

Review requested:

• @nodejs/ffi

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.31%. Comparing base (dd9f4da) to head (0c5e7ae).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66197      +/-   ##
==========================================
+ Coverage   90.29%   90.31%   +0.02%     
==========================================
  Files         790      790              
  Lines      272508   272576      +68     
  Branches    52028    52066      +38     
==========================================
+ Hits       246071   246189     +118     
+ Misses      16905    16867      -38     
+ Partials     9532     9520      -12     

Files with missing lines	Coverage Δ
lib/internal/ffi-shared-buffer.js	59.37% <100.00%> (+3.63%)	⬆️
lib/internal/ffi/fast-api.js	94.82% <100.00%> (+0.32%)	⬆️
src/ffi/types.cc	60.88% <100.00%> (+7.16%)	⬆️

... and 31 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.