国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Let’s explore the implementation principle of fs module watch in node,

const fs = require('fs');
var fileName = 'a.txt';
fs.watch(fileName, (function () {
    var count = 0;
    return function () {
        count++;
        console.log("文件" + fileName + " 內(nèi)容剛剛改變。。第" + count + "次");
    };
})());
console.log("watching file...");

How does fs implement event notifications in response to file changes? If it is by monitoring file size changes, or something else?

The following are some things seen through the node source code:

const FSEvent = process.binding('fs_event_wrap').FSEvent;

function FSWatcher() {
  EventEmitter.call(this);

  var self = this;
  this._handle = new FSEvent();
  this._handle.owner = this;
  this._handle.onchange = function(status, eventType, filename) {
    if (status < 0) {
      self._handle.close();
      const error = !filename ?
          errnoException(status, 'Error watching file for changes:') :
          errnoException(status,
                         `Error watching file ${filename} for changes:`);
      error.filename = filename;
      self.emit('error', error);
    } else {
      self.emit('change', eventType, filename);
    }
  };
}

The fs_event_wrap.cc that follows is basically in alien language.

The data volume I mounted in docker cannot listen to the event notification