Current File : //usr/share/nodejs/@types/node/wasi.d.ts
/**
* The WASI API provides an implementation of the [WebAssembly System Interface](https://wasi.dev/) specification. WASI gives sandboxed WebAssembly applications access to the
* underlying operating system via a collection of POSIX-like functions.
*
* ```js
* import { readFile } from 'fs/promises';
* import { WASI } from 'wasi';
* import { argv, env } from 'process';
*
* const wasi = new WASI({
* args: argv,
* env,
* preopens: {
* '/sandbox': '/some/real/path/that/wasm/can/access'
* }
* });
*
* // Some WASI binaries require:
* // const importObject = { wasi_unstable: wasi.wasiImport };
* const importObject = { wasi_snapshot_preview1: wasi.wasiImport };
*
* const wasm = await WebAssembly.compile(
* await readFile(new URL('./demo.wasm', import.meta.url))
* );
* const instance = await WebAssembly.instantiate(wasm, importObject);
*
* wasi.start(instance);
* ```
*
* To run the above example, create a new WebAssembly text format file named`demo.wat`:
*
* ```text
* (module
* ;; Import the required fd_write WASI function which will write the given io vectors to stdout
* ;; The function signature for fd_write is:
* ;; (File Descriptor, *iovs, iovs_len, nwritten) -> Returns number of bytes written
* (import "wasi_snapshot_preview1" "fd_write" (func $fd_write (param i32 i32 i32 i32) (result i32)))
*
* (memory 1)
* (export "memory" (memory 0))
*
* ;; Write 'hello world\n' to memory at an offset of 8 bytes
* ;; Note the trailing newline which is required for the text to appear
* (data (i32.const 8) "hello world\n")
*
* (func $main (export "_start")
* ;; Creating a new io vector within linear memory
* (i32.store (i32.const 0) (i32.const 8)) ;; iov.iov_base - This is a pointer to the start of the 'hello world\n' string
* (i32.store (i32.const 4) (i32.const 12)) ;; iov.iov_len - The length of the 'hello world\n' string
*
* (call $fd_write
* (i32.const 1) ;; file_descriptor - 1 for stdout
* (i32.const 0) ;; *iovs - The pointer to the iov array, which is stored at memory location 0
* (i32.const 1) ;; iovs_len - We're printing 1 string stored in an iov - so one.
* (i32.const 20) ;; nwritten - A place in memory to store the number of bytes written
* )
* drop ;; Discard the number of bytes written from the top of the stack
* )
* )
* ```
*
* Use [wabt](https://github.com/WebAssembly/wabt) to compile `.wat` to `.wasm`
*
* ```console
* $ wat2wasm demo.wat
* ```
*
* The `--experimental-wasi-unstable-preview1` CLI argument is needed for this
* example to run.
* @experimental
* @see [source](https://github.com/nodejs/node/blob/v18.0.0/lib/wasi.js)
*/
declare module "wasi" {
interface WASIOptions {
/**
* An array of strings that the WebAssembly application will
* see as command line arguments. The first argument is the virtual path to the
* WASI command itself.
*/
args?: string[] | undefined;
/**
* An object similar to `process.env` that the WebAssembly
* application will see as its environment.
*/
env?: object | undefined;
/**
* This object represents the WebAssembly application's
* sandbox directory structure. The string keys of `preopens` are treated as
* directories within the sandbox. The corresponding values in `preopens` are
* the real paths to those directories on the host machine.
*/
preopens?: NodeJS.Dict<string> | undefined;
/**
* By default, WASI applications terminate the Node.js
* process via the `__wasi_proc_exit()` function. Setting this option to `true`
* causes `wasi.start()` to return the exit code rather than terminate the
* process.
* @default false
*/
returnOnExit?: boolean | undefined;
/**
* The file descriptor used as standard input in the WebAssembly application.
* @default 0
*/
stdin?: number | undefined;
/**
* The file descriptor used as standard output in the WebAssembly application.
* @default 1
*/
stdout?: number | undefined;
/**
* The file descriptor used as standard error in the WebAssembly application.
* @default 2
*/
stderr?: number | undefined;
}
/**
* The `WASI` class provides the WASI system call API and additional convenience
* methods for working with WASI-based applications. Each `WASI` instance
* represents a distinct sandbox environment. For security purposes, each `WASI`instance must have its command-line arguments, environment variables, and
* sandbox directory structure configured explicitly.
* @since v13.3.0, v12.16.0
*/
class WASI {
constructor(options?: WASIOptions);
/**
* Attempt to begin execution of `instance` as a WASI command by invoking its`_start()` export. If `instance` does not contain a `_start()` export, or if`instance` contains an `_initialize()`
* export, then an exception is thrown.
*
* `start()` requires that `instance` exports a [`WebAssembly.Memory`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/Memory) named`memory`. If
* `instance` does not have a `memory` export an exception is thrown.
*
* If `start()` is called more than once, an exception is thrown.
* @since v13.3.0, v12.16.0
*/
start(instance: object): number; // TODO: avoid DOM dependency until WASM moved to own lib.
/**
* Attempt to initialize `instance` as a WASI reactor by invoking its`_initialize()` export, if it is present. If `instance` contains a `_start()`export, then an exception is thrown.
*
* `initialize()` requires that `instance` exports a [`WebAssembly.Memory`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/Memory) named`memory`.
* If `instance` does not have a `memory` export an exception is thrown.
*
* If `initialize()` is called more than once, an exception is thrown.
* @since v14.6.0, v12.19.0
*/
initialize(instance: object): void; // TODO: avoid DOM dependency until WASM moved to own lib.
/**
* `wasiImport` is an object that implements the WASI system call API. This object
* should be passed as the `wasi_snapshot_preview1` import during the instantiation
* of a [`WebAssembly.Instance`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/Instance).
* @since v13.3.0, v12.16.0
*/
readonly wasiImport: NodeJS.Dict<any>; // TODO: Narrow to DOM types
}
}
declare module "node:wasi" {
export * from "wasi";
}
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