filer/src/fs-watcher.js

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var EventEmitter = require('../lib/eventemitter.js');
var Path = require('./path.js');
var Intercom = require('../lib/intercom.js');
/**
* FSWatcher based on node.js' FSWatcher
* see https://github.com/joyent/node/blob/master/lib/fs.js
*/
function FSWatcher() {
EventEmitter.call(this);
var self = this;
var recursive = false;
var recursivePathPrefix;
var filename;
function onchange(path) {
// Watch for exact filename, or parent path when recursive is true.
if(filename === path || (recursive && path.indexOf(recursivePathPrefix) === 0)) {
self.trigger('change', 'change', path);
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}
}
// We support, but ignore the second arg, which node.js uses.
self.start = function(filename_, persistent_, recursive_) {
// Bail if we've already started (and therefore have a filename);
if(filename) {
return;
}
if(Path.isNull(filename_)) {
throw new Error('Path must be a string without null bytes.');
}
// TODO: get realpath for symlinks on filename...
// Filer's Path.normalize strips trailing slashes, which we use here.
// See https://github.com/js-platform/filer/issues/105
filename = Path.normalize(filename_);
// Whether to watch beneath this path or not
recursive = recursive_ === true;
// If recursive, construct a path prefix portion for comparisons later
// (i.e., '/path' becomes '/path/' so we can search within a filename for the
// prefix). We also take care to allow for '/' on its own.
if(recursive) {
recursivePathPrefix = filename === '/' ? '/' : filename + '/';
}
var intercom = Intercom.getInstance();
intercom.on('change', onchange);
};
self.close = function() {
var intercom = Intercom.getInstance();
intercom.off('change', onchange);
self.removeAllListeners('change');
};
}
FSWatcher.prototype = new EventEmitter();
FSWatcher.prototype.constructor = FSWatcher;
module.exports = FSWatcher;