103 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/**
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 * @author Deepkolos / https://github.com/deepkolos
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 */
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export class WorkerPool {
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	constructor( pool = 4 ) {
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		this.pool = pool;
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		this.queue = [];
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		this.workers = [];
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		this.workersResolve = [];
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		this.workerStatus = 0;
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	}
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	_initWorker( workerId ) {
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		if ( ! this.workers[ workerId ] ) {
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			const worker = this.workerCreator();
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			worker.addEventListener( 'message', this._onMessage.bind( this, workerId ) );
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			this.workers[ workerId ] = worker;
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		}
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	}
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	_getIdleWorker() {
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		for ( let i = 0; i < this.pool; i ++ )
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			if ( ! ( this.workerStatus & ( 1 << i ) ) ) return i;
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		return - 1;
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	}
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	_onMessage( workerId, msg ) {
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		const resolve = this.workersResolve[ workerId ];
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		resolve && resolve( msg );
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		if ( this.queue.length ) {
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			const { resolve, msg, transfer } = this.queue.shift();
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			this.workersResolve[ workerId ] = resolve;
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			this.workers[ workerId ].postMessage( msg, transfer );
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		} else {
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			this.workerStatus ^= 1 << workerId;
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		}
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	}
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	setWorkerCreator( workerCreator ) {
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		this.workerCreator = workerCreator;
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	}
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	setWorkerLimit( pool ) {
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		this.pool = pool;
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	}
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	postMessage( msg, transfer ) {
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		return new Promise( ( resolve ) => {
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			const workerId = this._getIdleWorker();
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			if ( workerId !== - 1 ) {
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				this._initWorker( workerId );
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				this.workerStatus |= 1 << workerId;
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				this.workersResolve[ workerId ] = resolve;
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				this.workers[ workerId ].postMessage( msg, transfer );
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			} else {
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				this.queue.push( { resolve, msg, transfer } );
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			}
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		} );
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	}
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	dispose() {
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		this.workers.forEach( ( worker ) => worker.terminate() );
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		this.workersResolve.length = 0;
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		this.workers.length = 0;
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		this.queue.length = 0;
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		this.workerStatus = 0;
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	}
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}
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