cryogen-core/src/cryogen_core/watcher.clj
Jan Stępień 0d1149a9c2 Use Hawk in cryogen-core.watcher
This is a follow-up to PR #46. It replaces the 300ms loop with a file
watcher. Hawk is a wrapper around java.nio.file.WatchService coming with
proper OS X support.

Now rebuilds should be instantaneous.
2016-03-13 16:43:14 +01:00

36 lines
1.2 KiB
Clojure

(ns cryogen-core.watcher
(:require [clojure.java.io :refer [file]]
[cryogen-core.io :refer [ignore]]
[pandect.algo.md5 :refer [md5]]
[hawk.core :as hawk]
[clojure.set :as set]))
(defn get-assets [path ignored-files]
(->> path
file
file-seq
(filter #(not (.isDirectory ^java.io.File %)))
(filter (ignore ignored-files))))
(defn checksums [path ignored-files]
(let [files (get-assets path ignored-files)]
(zipmap (map md5 files) files)))
(defn find-changes [old-sums new-sums]
(let [old-sum-set (-> old-sums keys set)
new-sum-set (-> new-sums keys set)]
(when-some [changes (set/difference new-sum-set old-sum-set)]
(vals (select-keys new-sums changes)))))
(defn watch-assets [sums root ignored-files action]
(let [new-sums (checksums root ignored-files)]
(when (find-changes @sums new-sums)
(action)
(reset! sums new-sums))))
(defn start-watcher! [root ignored-files action]
(let [sums (atom (checksums root ignored-files))
handler (fn [ctx e]
(watch-assets sums root ignored-files action))]
(hawk/watch! [{:paths [root]
:handler handler}])))