All files / lib diagnostics_channel.js

100% Statements 121/121
100% Branches 25/25
90% Functions 9/10
100% Lines 121/121

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 12212x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 12x 8x 8x 8x 12x 12x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 12x 12x 4x 4x 12x 12x 5x 6x 6x 6x 6x 1x 1x 1x 1x 6x 5x 12x 12x 12x 12x 1550x 1550x 1550x 12x 12x 2x 2x 2x 2x 12x 12x 7x 7x 7x 7x 12x 12x 26063x 26063x 12x 12x 12x 12x 12x 12x 1553x 1553x 1553x 1553x 1553x 1551x 1553x 1x 1x 1550x 1550x 1550x 1550x 1553x 12x 3x 3x 3x 3x 3x 1x 1x 2x 2x 3x 12x 12x 12x 12x 12x 12x  
'use strict';
 
const {
  ArrayPrototypeIndexOf,
  ArrayPrototypePush,
  ArrayPrototypeSplice,
  ObjectCreate,
  ObjectGetPrototypeOf,
  ObjectSetPrototypeOf,
  SymbolHasInstance,
} = primordials;
 
const {
  codes: {
    ERR_INVALID_ARG_TYPE,
  }
} = require('internal/errors');
const {
  validateFunction,
} = require('internal/validators');
 
const { triggerUncaughtException } = internalBinding('errors');
 
const { WeakReference } = internalBinding('util');
 
// TODO(qard): should there be a C++ channel interface?
class ActiveChannel {
  subscribe(subscription) {
    validateFunction(subscription, 'subscription');
    ArrayPrototypePush(this._subscribers, subscription);
  }
 
  unsubscribe(subscription) {
    const index = ArrayPrototypeIndexOf(this._subscribers, subscription);
    if (index >= 0) {
      ArrayPrototypeSplice(this._subscribers, index, 1);
 
      // When there are no more active subscribers, restore to fast prototype.
      if (!this._subscribers.length) {
        // eslint-disable-next-line no-use-before-define
        ObjectSetPrototypeOf(this, Channel.prototype);
      }
    }
  }
 
  get hasSubscribers() {
    return true;
  }
 
  publish(data) {
    for (let i = 0; i < this._subscribers.length; i++) {
      try {
        const onMessage = this._subscribers[i];
        onMessage(data, this.name);
      } catch (err) {
        process.nextTick(() => {
          triggerUncaughtException(err, false);
        });
      }
    }
  }
}
 
class Channel {
  constructor(name) {
    this._subscribers = undefined;
    this.name = name;
  }
 
  static [SymbolHasInstance](instance) {
    const prototype = ObjectGetPrototypeOf(instance);
    return prototype === Channel.prototype ||
           prototype === ActiveChannel.prototype;
  }
 
  subscribe(subscription) {
    ObjectSetPrototypeOf(this, ActiveChannel.prototype);
    this._subscribers = [];
    this.subscribe(subscription);
  }
 
  get hasSubscribers() {
    return false;
  }
 
  publish() {}
}
 
const channels = ObjectCreate(null);
 
function channel(name) {
  let channel;
  const ref = channels[name];
  if (ref) channel = ref.get();
  if (channel) return channel;
 
  if (typeof name !== 'string' && typeof name !== 'symbol') {
    throw new ERR_INVALID_ARG_TYPE('channel', ['string', 'symbol'], name);
  }
 
  channel = new Channel(name);
  channels[name] = new WeakReference(channel);
  return channel;
}
 
function hasSubscribers(name) {
  let channel;
  const ref = channels[name];
  if (ref) channel = ref.get();
  if (!channel) {
    return false;
  }
 
  return channel.hasSubscribers;
}
 
module.exports = {
  channel,
  hasSubscribers,
  Channel
};