New Folder Scanner - WIP

scanner/change_detector.go

@@ -0,0 +1,113 @@
+package scanner
+
+import (
+	"os"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/cloudsonic/sonic-server/log"
+)
+
+type ChangeDetector struct {
+	rootFolder string
+	lastUpdate time.Time
+	dirMap     map[string]time.Time
+}
+
+func NewChangeDetector(rootFolder string, lastUpdate time.Time) *ChangeDetector {
+	return &ChangeDetector{
+		rootFolder: rootFolder,
+		lastUpdate: lastUpdate,
+		dirMap:     map[string]time.Time{},
+	}
+}
+
+func (s *ChangeDetector) Scan() (changed []string, deleted []string, err error) {
+	start := time.Now()
+	newMap := make(map[string]time.Time)
+	err = s.loadMap(s.rootFolder, newMap)
+	if err != nil {
+		return
+	}
+	changed, deleted, err = s.checkForUpdates(s.dirMap, newMap)
+	if err != nil {
+		return
+	}
+	elapsed := time.Since(start)
+
+	log.Trace("Folder analysis complete\n", "total", len(newMap), "changed", len(changed), "deleted", len(deleted), "elapsed", elapsed)
+	s.dirMap = newMap
+	return
+}
+
+func (s *ChangeDetector) loadDir(dirPath string) (children []string, lastUpdated time.Time, err error) {
+	dir, err := os.Open(dirPath)
+	if err != nil {
+		return
+	}
+	dirInfo, err := os.Stat(dirPath)
+	if err != nil {
+		return
+	}
+	lastUpdated = dirInfo.ModTime()
+
+	files, err := dir.Readdir(-1)
+	if err != nil {
+		return
+	}
+	for _, f := range files {
+		if f.IsDir() {
+			children = append(children, path.Join(dirPath, f.Name()))
+		} else {
+			if f.ModTime().After(lastUpdated) {
+				lastUpdated = f.ModTime()
+			}
+		}
+	}
+	return
+}
+
+func (s *ChangeDetector) loadMap(rootPath string, dirMap map[string]time.Time) error {
+	children, lastUpdated, err := s.loadDir(rootPath)
+	if err != nil {
+		return err
+	}
+	for _, c := range children {
+		err := s.loadMap(c, dirMap)
+		if err != nil {
+			return err
+		}
+	}
+
+	dir := s.getRelativePath(rootPath)
+	dirMap[dir] = lastUpdated
+
+	return nil
+}
+
+func (s *ChangeDetector) getRelativePath(subfolder string) string {
+	dir := strings.TrimPrefix(subfolder, s.rootFolder)
+	if dir == "" {
+		dir = "."
+	}
+	return dir
+}
+
+func (s *ChangeDetector) checkForUpdates(oldMap map[string]time.Time, newMap map[string]time.Time) (changed []string, deleted []string, err error) {
+	for dir, lastUpdated := range newMap {
+		oldLastUpdated, ok := oldMap[dir]
+		if !ok {
+			oldLastUpdated = s.lastUpdate
+		}
+		if lastUpdated.After(oldLastUpdated) {
+			changed = append(changed, dir)
+		}
+	}
+	for dir := range oldMap {
+		if _, ok := newMap[dir]; !ok {
+			deleted = append(deleted, dir)
+		}
+	}
+	return
+}