@bun-win32/clfsw32

Zero-dependency, zero-overhead Win32 Clfsw32 bindings for Bun on Windows.

Overview

@bun-win32/clfsw32 exposes the clfsw32.dll exports using Bun's FFI. It provides a single class, Clfsw32, which lazily binds native symbols on first use. You can optionally preload a subset or all symbols up-front via Preload().

It binds all 53 documented Common Log File System user-mode APIs — the clfsw32.h log/container/marshaling/archive surface plus the clfsmgmtw32.h management surface — for high-performance transactional write-ahead logging, the same engine that backs TxF, TxR, and Kernel Transaction Manager.

The bindings are strongly typed for a smooth DX in TypeScript.

Features

• Bun-first ergonomics on Windows 10/11.
• Direct FFI to clfsw32.dll (Common Log File System: log files, containers, marshaling areas, records, LSN algebra, archival, and CLFS management policy).
• In-source docs in structs/Clfsw32.ts with links to Microsoft Docs.
• Lazy binding on first call; optional eager preload (Clfsw32.Preload()).
• No wrapper overhead; calls map 1:1 to native APIs.
• Strongly-typed Win32 aliases (see types/Clfsw32.ts).

Requirements

• Bun runtime
• Windows 10 or later

[!NOTE] CreateLogFile, ValidateLog, and the LSN-algebra functions work from a standard token. Creating containers and appending records (AddLogContainer, CreateLogMarshallingArea, ReserveAndAppendLog, the CLFS management APIs) flow through CLFS.sys and require an elevated process; unelevated they return ERROR_ACCESS_DENIED.

Installation

bun add @bun-win32/clfsw32

Quick Start

import Clfsw32, { GENERIC_READ, GENERIC_WRITE, INVALID_HANDLE_VALUE, OPEN_ALWAYS } from '@bun-win32/clfsw32';

// CLFS appends ".blf"; the "LOG:" prefix selects the dedicated-log namespace.
const name = Buffer.from('LOG:C:\\Temp\\demo\0', 'utf16le');

const hLog = Clfsw32.CreateLogFile(name.ptr, GENERIC_READ | GENERIC_WRITE, 0, null, OPEN_ALWAYS, 0);
if (hLog !== INVALID_HANDLE_VALUE) {
  // Validate the on-disk log metadata.
  console.log('valid:', Clfsw32.ValidateLog(name.ptr, null, null, Buffer.alloc(4).ptr) !== 0);

  // CLFS_LSN is an 8-byte value returned by value; compose then decompose one.
  const lsn = Clfsw32.LsnCreate(5, 0x2000, 7); // -> bigint
  const buf = Buffer.alloc(8);
  buf.writeBigUInt64LE(lsn, 0);
  console.log(Clfsw32.LsnContainer(buf.ptr), Clfsw32.LsnBlockOffset(buf.ptr), Clfsw32.LsnRecordSequence(buf.ptr));

  Clfsw32.DeleteLogFile(name.ptr, null);
}

[!NOTE] AI agents: see AI.md for the package binding contract and source-navigation guidance. It explains how to use the package without scanning the entire implementation.

Examples

Run the included examples:

bun run example:diagnostic   # thorough CLFS subsystem diagnostic + LSN ABI proof
bun run example:ledger       # animated write-ahead-log / LSN cartographer

Notes

• Either rely on lazy binding or call Clfsw32.Preload().
• Windows only. Bun runtime required.
• SAL types & naming: nullability is in the type — Optional<T> (formally optional, SAL _*opt_) and Nullable<T> (plain [in]/[out] the docs say can be NULL), the null sentinel derived from T (null for pointers LP*/P*, 0n for handles/by-value addresses); direction is in the parameter name — _out (_Out_), _in_out (_Inout_), _In_ bare. See AI.md and the repo AGENTS.md.