All files / lib/internal/process task_queues.js

100% Statements 173/173
100% Branches 55/55
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 17428x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 65126x 65126x 65126x 28x 527474x 527474x 527474x 28x 28x 28x 28x 32565x 32565x 32565x 32565x 32565x 5606x 5606x 32565x 28x 197731x 197731x 197731x 201177x 682295x 682295x 682295x 682295x 682295x 682295x 94101x 681873x 588176x 588176x 588176x 588176x 588176x 588176x 588176x 588176x 588176x 682295x 681993x 681993x 681993x 680839x 680839x 680839x 199660x 197731x 197731x 197731x 197731x 28x 28x 28x 685056x 685056x 685056x 685056x 685056x 684939x 684939x 684939x 685056x 685056x 685056x 685056x 685056x 25946x 25946x 25946x 25946x 684939x 684939x 685038x 684937x 684937x 684937x 684937x 684937x 684937x 684937x 684937x 684937x 685045x 684928x 685056x 28x 523x 523x 523x 523x 523x 523x 523x 523x 523x 523x 28x 28x 28x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 28x 28x 28x 1254x 1254x 1254x 1254x 1254x 1254x 1254x 1254x 28x 28x 28x  
'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
};