All files / lib/internal/process task_queues.js

100% Statements 173/173
100% Branches 54/54
100% Functions 8/8
100% Lines 173/173

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 17424x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 66234x 66234x 66234x 24x 529439x 529439x 529439x 24x 24x 24x 24x 33117x 33117x 33117x 33117x 33117x 5719x 5719x 33117x 24x 199944x 199944x 199944x 203244x 676585x 676585x 676585x 676585x 676585x 676585x 87535x 676171x 589038x 589038x 589038x 589038x 589038x 589038x 589038x 589038x 589038x 676585x 676304x 676304x 676304x 675157x 675157x 675157x 201796x 199944x 199944x 199944x 199944x 24x 24x 24x 679025x 679025x 679025x 679025x 679025x 678913x 678913x 678913x 679025x 679025x 679025x 679025x 679025x 25912x 25912x 25912x 25912x 678913x 678913x 679007x 678912x 678912x 678912x 678912x 678912x 678912x 678912x 678912x 678912x 679014x 678902x 679025x 24x 520x 520x 520x 520x 520x 520x 520x 520x 520x 520x 24x 24x 24x 530x 530x 530x 530x 530x 530x 530x 530x 530x 530x 530x 24x 24x 24x 803x 803x 803x 803x 803x 803x 803x 803x 24x 24x 24x  
'use strict';
 
const {
  Array,
  FunctionPrototypeBind,
} = primordials;
 
const {
  // For easy access to the nextTick state in the C++ land,
  // and to avoid unnecessary calls into JS land.
  tickInfo,
  // Used to run V8's micro task queue.
  runMicrotasks,
  setTickCallback,
  enqueueMicrotask
} = internalBinding('task_queue');
 
const {
  setHasRejectionToWarn,
  hasRejectionToWarn,
  listenForRejections,
  processPromiseRejections
} = require('internal/process/promises');
 
const {
  getDefaultTriggerAsyncId,
  newAsyncId,
  initHooksExist,
  destroyHooksExist,
  emitInit,
  emitBefore,
  emitAfter,
  emitDestroy,
  symbols: { async_id_symbol, trigger_async_id_symbol }
} = require('internal/async_hooks');
const FixedQueue = require('internal/fixed_queue');
 
const {
  validateFunction,
} = require('internal/validators');
 
const { AsyncResource } = require('async_hooks');
 
// *Must* match Environment::TickInfo::Fields in src/env.h.
const kHasTickScheduled = 0;
 
function hasTickScheduled() {
  return tickInfo[kHasTickScheduled] === 1;
}
 
function setHasTickScheduled(value) {
  tickInfo[kHasTickScheduled] = value ? 1 : 0;
}
 
const queue = new FixedQueue();
 
// Should be in sync with RunNextTicksNative in node_task_queue.cc
function runNextTicks() {
  if (!hasTickScheduled() && !hasRejectionToWarn())
    runMicrotasks();
  if (!hasTickScheduled() && !hasRejectionToWarn())
    return;
 
  processTicksAndRejections();
}
 
function processTicksAndRejections() {
  let tock;
  do {
    while ((tock = queue.shift()) !== null) {
      const asyncId = tock[async_id_symbol];
      emitBefore(asyncId, tock[trigger_async_id_symbol], tock);
 
      try {
        const callback = tock.callback;
        if (tock.args === undefined) {
          callback();
        } else {
          const args = tock.args;
          switch (args.length) {
            case 1: callback(args[0]); break;
            case 2: callback(args[0], args[1]); break;
            case 3: callback(args[0], args[1], args[2]); break;
            case 4: callback(args[0], args[1], args[2], args[3]); break;
            default: callback(...args);
          }
        }
      } finally {
        if (destroyHooksExist())
          emitDestroy(asyncId);
      }
 
      emitAfter(asyncId);
    }
    runMicrotasks();
  } while (!queue.isEmpty() || processPromiseRejections());
  setHasTickScheduled(false);
  setHasRejectionToWarn(false);
}
 
// `nextTick()` will not enqueue any callback when the process is about to
// exit since the callback would not have a chance to be executed.
function nextTick(callback) {
  validateFunction(callback, 'callback');
 
  if (process._exiting)
    return;
 
  let args;
  switch (arguments.length) {
    case 1: break;
    case 2: args = [arguments[1]]; break;
    case 3: args = [arguments[1], arguments[2]]; break;
    case 4: args = [arguments[1], arguments[2], arguments[3]]; break;
    default:
      args = new Array(arguments.length - 1);
      for (let i = 1; i < arguments.length; i++)
        args[i - 1] = arguments[i];
  }
 
  if (queue.isEmpty())
    setHasTickScheduled(true);
  const asyncId = newAsyncId();
  const triggerAsyncId = getDefaultTriggerAsyncId();
  const tickObject = {
    [async_id_symbol]: asyncId,
    [trigger_async_id_symbol]: triggerAsyncId,
    callback,
    args
  };
  if (initHooksExist())
    emitInit(asyncId, 'TickObject', triggerAsyncId, tickObject);
  queue.push(tickObject);
}
 
function runMicrotask() {
  this.runInAsyncScope(() => {
    const callback = this.callback;
    try {
      callback();
    } finally {
      this.emitDestroy();
    }
  });
}
 
const defaultMicrotaskResourceOpts = { requireManualDestroy: true };
 
function queueMicrotask(callback) {
  validateFunction(callback, 'callback');
 
  const asyncResource = new AsyncResource(
    'Microtask',
    defaultMicrotaskResourceOpts
  );
  asyncResource.callback = callback;
 
  enqueueMicrotask(FunctionPrototypeBind(runMicrotask, asyncResource));
}
 
module.exports = {
  setupTaskQueue() {
    // Sets the per-isolate promise rejection callback
    listenForRejections();
    // Sets the callback to be run in every tick.
    setTickCallback(processTicksAndRejections);
    return {
      nextTick,
      runNextTicks
    };
  },
  queueMicrotask
};