/// <reference types="node" />
import { EventEmitter } from 'events';
import { WorkerProcess } from '../process';
/**
 * Maintains a pool of WorkerProcess instances for running WASI
 * modules.
 * Workers are reused after termination.
 * Terminated pids are reported to parent processes for interoperation
 * with wait calls.
 */
declare class WorkerPool extends EventEmitter implements ProcessLoader {
    running: Set<WorkerPoolItem>;
    free: WorkerPoolItem[];
    loader: ProcessLoader;
    constructor();
    spawn(wasm: string, argv: string[], env?: {}): WorkerPoolItem;
    populate(item: WorkerPoolItem, spawnArgs: {
        wasm: string;
        argv: string[];
        env?: {};
    }): void;
    exec(item: WorkerPoolItem, spawnArgs: SpawnArgs): void;
    handleSpawns(parent: WorkerProcess): void;
    parseArgv(argv: Uint8Array[]): string[];
    parseEnviron(envp: Uint8Array[]): {};
}
declare type WorkerPoolItem = {
    process: WorkerProcess;
    promise: Promise<{}>;
};
interface ProcessLoader {
    spawn(wasm: string, argv: string[], env?: {}): WorkerPoolItem;
    populate(item: WorkerPoolItem, spawnArgs: SpawnArgs): void;
    exec(item: WorkerPoolItem, spawnArgs: SpawnArgs): void;
}
declare type SpawnArgs = {
    wasm: string;
    argv: string[];
    env?: {};
};
export { WorkerPool, WorkerPoolItem, ProcessLoader, SpawnArgs };