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concurrent_promise

Parallel processing module for JavaScript that can specify the number of concurrent executions.

Fra 27.03.2020. Se den seneste versjonen.

Dette scriptet burde ikke installeres direkte. Det er et bibliotek for andre script å inkludere med det nye metadirektivet // @require https://update.greasyfork.org/scripts/398566/785036/concurrent_promise.js 

( ( exports ) => {
'use strict';

const
    version = '1.0.1',
    
    execute = async ( promise_functions, max_concurrent_worker = 10 ) => {
        let concurrent_workers = Array( max_concurrent_worker ).fill( null ),
            waiting_worker_queue = [],
            success_list = [],
            failure_list = [],
            
            log_debug = ( header ) => {
                if ( ! exports.debug_mode ) {
                    return;
                }
                if ( header ) {
                    console.log( header );
                }
                console.log( '- concurrent_workers:', concurrent_workers );
                console.log( '- waiting_worker_queue:', waiting_worker_queue );
                console.log( '- success_list:', success_list );
                console.log( '- failure_list:', failure_list );
            },
            
            attempt_work_delegation = () => {
                log_debug( '*** attempt_work_delegation()' );
                
                if ( waiting_worker_queue.length <= 0 ) {
                    return;
                }
                
                let target_worker_id = -1;
                
                for ( let worker_id = 0; worker_id < concurrent_workers.length; worker_id ++ ) {
                    if ( ! concurrent_workers[ worker_id ] ) {
                        target_worker_id = worker_id;
                        break;
                    }
                }
                
                if ( target_worker_id < 0 ) {
                    return;
                }
                
                let target_worker = concurrent_workers[ target_worker_id ] = waiting_worker_queue.shift(),
                    target_promise = target_worker.promise = target_worker.promise_function(),
                    
                    finish = ( is_success, result ) => {
                        target_worker.is_success = is_success;
                        target_worker.result = result;
                        ( is_success ? success_list : failure_list ).push( target_worker );
                        target_worker.resolve( result );
                        concurrent_workers[ target_worker_id ] = null;
                        attempt_work_delegation();
                    };
                
                target_worker.worker_id = target_worker_id;
                
                target_promise
                .then( ( result ) => {
                    finish( true, result );
                } )
                .catch( ( result ) => {
                    finish( false, result );
                } );
            },
            
            add_worker = ( worker ) => {
                waiting_worker_queue.push( worker );
                attempt_work_delegation();
            },
            
            wrap_promise_function = ( promise_function, call_index ) => {
                return new Promise( ( resolve, reject ) => {
                    add_worker( {
                        call_index : call_index,
                        promise_function : promise_function,
                        resolve : resolve,
                        reject : reject,
                    } );
                } );
            },
            
            promise_results = await Promise.all( promise_functions.map( ( promise_function, call_index ) => wrap_promise_function( promise_function, call_index ) ) );
        
        success_list.sort( ( a, b ) => a.call_index - b.call_index );
        failure_list.sort( ( a, b ) => a.call_index - b.call_index );
        
        log_debug( '*** concurrent_executor() : end' );
        
        let result_info = {
                promise_results : promise_results,
                success_list : success_list,
                failure_list : failure_list,
            };
        
        if ( exports.debug_mode ) {
            Object.assign( result_info, {
                waiting_worker_queue : waiting_worker_queue,
                concurrent_workers : concurrent_workers,
            } );
        }
        
        return result_info;
    };

Object.assign( exports, {
    version : version,
    execute : execute,
    debug_mode : false,
} );

} )( ( typeof exports != 'undefined' ) ? exports : ( ( typeof window != 'undefined' ) ? window : this )[ 'concurrent_promise' ] = {} );