All files / lib/internal/process task_queues.js

100% Statements 173/173
100% Branches 53/53
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 17427x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 27x 66222x 66222x 66222x 27x 529264x 529264x 529264x 27x 27x 27x 27x 33111x 33111x 33111x 33111x 33111x 5681x 5681x 33111x 27x 199707x 199707x 199707x 203069x 677262x 677262x 677262x 677262x 677262x 677262x 88334x 676838x 588915x 588915x 588915x 588915x 588915x 588915x 588915x 588915x 588915x 677262x 676982x 676982x 676982x 675830x 675830x 675830x 201617x 199707x 199707x 199707x 199707x 27x 27x 27x 679748x 679748x 679748x 679748x 679748x 679632x 679632x 679632x 679748x 679748x 679748x 679748x 679748x 25904x 25904x 25904x 25904x 679632x 679632x 679730x 679631x 679631x 679631x 679631x 679631x 679631x 679631x 679631x 679631x 679737x 679628x 679748x 27x 523x 523x 523x 523x 523x 523x 523x 523x 523x 523x 27x 27x 27x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 27x 27x 27x 804x 804x 804x 804x 804x 804x 804x 804x 27x 27x 27x  
'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
};