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| 1 | +'use strict'; |
| 2 | + |
| 3 | +class Queue { |
| 4 | + constructor(concurrency) { |
| 5 | + this.concurrency = concurrency; |
| 6 | + this.count = 0; |
| 7 | + this.waiting = []; |
| 8 | + this.waitingStart = []; |
| 9 | + this.onProcess = null; |
| 10 | + this.onDone = null; |
| 11 | + this.onSuccess = null; |
| 12 | + this.onFailure = null; |
| 13 | + this.onDrain = null; |
| 14 | + this.waitTimeout = Infinity; |
| 15 | + this.processTimeout = Infinity; |
| 16 | + } |
| 17 | + static channels(concurrency) { |
| 18 | + return new Queue(concurrency); |
| 19 | + } |
| 20 | + wait(msec) { |
| 21 | + this.waitTimeout = msec; |
| 22 | + return this; |
| 23 | + } |
| 24 | + timeout(msec) { |
| 25 | + this.processTimeout = msec; |
| 26 | + return this; |
| 27 | + } |
| 28 | + add(task) { |
| 29 | + const hasChannel = this.count < this.concurrency; |
| 30 | + if (hasChannel) { |
| 31 | + this.next(task); |
| 32 | + return; |
| 33 | + } |
| 34 | + this.waiting.push(task); |
| 35 | + this.waitingStart.push(Date.now()); |
| 36 | + } |
| 37 | + next(task) { |
| 38 | + this.count++; |
| 39 | + let timer = null; |
| 40 | + let finished = false; |
| 41 | + const { processTimeout, onProcess } = this; |
| 42 | + const finish = (err, res) => { |
| 43 | + if (finished) return; |
| 44 | + finished = true; |
| 45 | + if (timer) clearTimeout(timer); |
| 46 | + this.count--; |
| 47 | + this.finish(err, res); |
| 48 | + if (this.waiting.length > 0) this.takeNext(); |
| 49 | + }; |
| 50 | + if (processTimeout !== Infinity) { |
| 51 | + const err = new Error('Process timed out'); |
| 52 | + timer = setTimeout(finish, processTimeout, err, task); |
| 53 | + } |
| 54 | + onProcess(task, finish); |
| 55 | + } |
| 56 | + takeNext() { |
| 57 | + const { waiting, waitingStart, waitTimeout } = this; |
| 58 | + const task = waiting.shift(); |
| 59 | + const start = waitingStart.shift(); |
| 60 | + if (waitTimeout !== Infinity) { |
| 61 | + const delay = Date.now() - start; |
| 62 | + if (delay > waitTimeout) { |
| 63 | + const err = new Error('Waiting timed out'); |
| 64 | + this.finish(err, task); |
| 65 | + if (waiting.length > 0) this.takeNext(); |
| 66 | + return; |
| 67 | + } |
| 68 | + } |
| 69 | + this.next(task); |
| 70 | + return; |
| 71 | + } |
| 72 | + finish(err, res) { |
| 73 | + const { onFailure, onSuccess, onDone, onDrain } = this; |
| 74 | + if (err) { |
| 75 | + if (onFailure) onFailure(err, res); |
| 76 | + } else if (onSuccess) { |
| 77 | + onSuccess(res); |
| 78 | + } |
| 79 | + if (onDone) onDone(err, res); |
| 80 | + if (this.count === 0 && onDrain) onDrain(); |
| 81 | + } |
| 82 | + process(listener) { |
| 83 | + this.onProcess = listener; |
| 84 | + return this; |
| 85 | + } |
| 86 | + done(listener) { |
| 87 | + this.onDone = listener; |
| 88 | + return this; |
| 89 | + } |
| 90 | + success(listener) { |
| 91 | + this.onSuccess = listener; |
| 92 | + return this; |
| 93 | + } |
| 94 | + failure(listener) { |
| 95 | + this.onFailure = listener; |
| 96 | + return this; |
| 97 | + } |
| 98 | + drain(listener) { |
| 99 | + this.onDrain = listener; |
| 100 | + return this; |
| 101 | + } |
| 102 | +} |
| 103 | + |
| 104 | +// Usage |
| 105 | + |
| 106 | +const job = (task, next) => { |
| 107 | + console.log(`Process: ${task.name}`); |
| 108 | + setTimeout(next, task.interval, null, task).unref(); |
| 109 | +}; |
| 110 | + |
| 111 | +const queue = Queue.channels(3) |
| 112 | + .wait(4000) |
| 113 | + .timeout(5000) |
| 114 | + .process(job) |
| 115 | + .done((err, task) => console.log(`Done: ${task.name}`)) |
| 116 | + .success(task => console.log(`Success: ${task.name}`)) |
| 117 | + .failure((err, task) => console.log(`Failure: ${err} ${task.name}`)) |
| 118 | + .drain(() => console.log('Queue drain')); |
| 119 | + |
| 120 | +for (let i = 0; i < 10; i++) { |
| 121 | + queue.add({ name: `Task${i}`, interval: i * 1000 }); |
| 122 | +} |
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