Style: code style

adapter/provider/fetcher.go

@@ -0,0 +1,184 @@
+package provider
+
+import (
+	"bytes"
+	"crypto/md5"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/Dreamacro/clash/log"
+)
+
+var (
+	fileMode os.FileMode = 0666
+	dirMode  os.FileMode = 0755
+)
+
+type parser = func([]byte) (interface{}, error)
+
+type fetcher struct {
+	name      string
+	vehicle   Vehicle
+	updatedAt *time.Time
+	ticker    *time.Ticker
+	done      chan struct{}
+	hash      [16]byte
+	parser    parser
+	onUpdate  func(interface{})
+}
+
+func (f *fetcher) Name() string {
+	return f.name
+}
+
+func (f *fetcher) VehicleType() VehicleType {
+	return f.vehicle.Type()
+}
+
+func (f *fetcher) Initial() (interface{}, error) {
+	var (
+		buf     []byte
+		err     error
+		isLocal bool
+	)
+	if stat, fErr := os.Stat(f.vehicle.Path()); fErr == nil {
+		buf, err = ioutil.ReadFile(f.vehicle.Path())
+		modTime := stat.ModTime()
+		f.updatedAt = &modTime
+		isLocal = true
+	} else {
+		buf, err = f.vehicle.Read()
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	proxies, err := f.parser(buf)
+	if err != nil {
+		if !isLocal {
+			return nil, err
+		}
+
+		// parse local file error, fallback to remote
+		buf, err = f.vehicle.Read()
+		if err != nil {
+			return nil, err
+		}
+
+		proxies, err = f.parser(buf)
+		if err != nil {
+			return nil, err
+		}
+
+		isLocal = false
+	}
+
+	if f.vehicle.Type() != File && !isLocal {
+		if err := safeWrite(f.vehicle.Path(), buf); err != nil {
+			return nil, err
+		}
+	}
+
+	f.hash = md5.Sum(buf)
+
+	// pull proxies automatically
+	if f.ticker != nil {
+		go f.pullLoop()
+	}
+
+	return proxies, nil
+}
+
+func (f *fetcher) Update() (interface{}, bool, error) {
+	buf, err := f.vehicle.Read()
+	if err != nil {
+		return nil, false, err
+	}
+
+	now := time.Now()
+	hash := md5.Sum(buf)
+	if bytes.Equal(f.hash[:], hash[:]) {
+		f.updatedAt = &now
+		return nil, true, nil
+	}
+
+	proxies, err := f.parser(buf)
+	if err != nil {
+		return nil, false, err
+	}
+
+	if f.vehicle.Type() != File {
+		if err := safeWrite(f.vehicle.Path(), buf); err != nil {
+			return nil, false, err
+		}
+	}
+
+	f.updatedAt = &now
+	f.hash = hash
+
+	return proxies, false, nil
+}
+
+func (f *fetcher) Destroy() error {
+	if f.ticker != nil {
+		f.done <- struct{}{}
+	}
+	return nil
+}
+
+func (f *fetcher) pullLoop() {
+	for {
+		select {
+		case <-f.ticker.C:
+			elm, same, err := f.Update()
+			if err != nil {
+				log.Warnln("[Provider] %s pull error: %s", f.Name(), err.Error())
+				continue
+			}
+
+			if same {
+				log.Debugln("[Provider] %s's proxies doesn't change", f.Name())
+				continue
+			}
+
+			log.Infoln("[Provider] %s's proxies update", f.Name())
+			if f.onUpdate != nil {
+				f.onUpdate(elm)
+			}
+		case <-f.done:
+			f.ticker.Stop()
+			return
+		}
+	}
+}
+
+func safeWrite(path string, buf []byte) error {
+	dir := filepath.Dir(path)
+
+	if _, err := os.Stat(dir); os.IsNotExist(err) {
+		if err := os.MkdirAll(dir, dirMode); err != nil {
+			return err
+		}
+	}
+
+	return ioutil.WriteFile(path, buf, fileMode)
+}
+
+func newFetcher(name string, interval time.Duration, vehicle Vehicle, parser parser, onUpdate func(interface{})) *fetcher {
+	var ticker *time.Ticker
+	if interval != 0 {
+		ticker = time.NewTicker(interval)
+	}
+
+	return &fetcher{
+		name:     name,
+		ticker:   ticker,
+		vehicle:  vehicle,
+		parser:   parser,
+		done:     make(chan struct{}, 1),
+		onUpdate: onUpdate,
+	}
+}