All files / lib/internal/process task_queues.js

100% Statements 174/174
100% Branches 53/53
100% Functions 8/8
100% Lines 174/174

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 17523x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 23x 63164x 63164x 63164x 23x 492420x 492420x 492420x 23x 23x 23x 23x 31582x 31582x 31582x 31582x 31582x 5546x 5546x 31582x 23x 185678x 185678x 185678x 188180x 624676x 624676x 624676x 624676x 624676x 624676x 81157x 624569x 543518x 543518x 543518x 543518x 543518x 543518x 543518x 543518x 543518x 624676x 624573x 624573x 624573x 623427x 623427x 623427x 186931x 185678x 185678x 185678x 185678x 23x 23x 23x 625031x 625031x 625031x 625031x 625031x 624924x 624924x 624924x 625031x 625031x 625031x 625031x 625031x 24150x 24150x 24150x 24150x 624924x 624924x 625013x 624924x 624924x 624924x 624924x 624924x 624924x 624924x 624924x 624924x 625021x 624924x 625031x 23x 252x 252x 252x 252x 252x 252x 252x 252x 252x 252x 23x 23x 23x 262x 262x 262x 262x 262x 262x 262x 262x 262x 262x 262x 23x 23x 23x 572x 572x 572x 572x 572x 572x 572x 572x 23x 23x 23x  
'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 {
  validateCallback,
  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()) {
      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) {
  validateCallback(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
};