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change_detector.go
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change_detector.go
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package scanner
import (
"context"
"io/ioutil"
"os"
"path/filepath"
"time"
"github.com/deluan/navidrome/log"
)
type dirInfo struct {
mdate time.Time
maybe bool
}
type dirInfoMap map[string]dirInfo
type changeDetector struct {
rootFolder string
dirMap dirInfoMap
}
func newChangeDetector(rootFolder string) *changeDetector {
return &changeDetector{
rootFolder: rootFolder,
dirMap: dirInfoMap{},
}
}
func (s *changeDetector) Scan(ctx context.Context, lastModifiedSince time.Time) (changed []string, deleted []string, err error) {
start := time.Now()
newMap := make(dirInfoMap)
err = s.loadMap(ctx, newMap, s.rootFolder, lastModifiedSince, false)
if err != nil {
return
}
changed, deleted, err = s.checkForUpdates(lastModifiedSince, newMap)
if err != nil {
return
}
elapsed := time.Since(start)
log.Trace(ctx, "Folder analysis complete", "total", len(newMap), "changed", len(changed), "deleted", len(deleted), "elapsed", elapsed)
s.dirMap = newMap
return
}
func (s *changeDetector) loadDir(ctx context.Context, dirPath string) (children []string, lastUpdated time.Time, err error) {
dirInfo, err := os.Stat(dirPath)
if err != nil {
log.Error(ctx, "Error stating dir", "path", dirPath, err)
return
}
lastUpdated = dirInfo.ModTime()
files, err := ioutil.ReadDir(dirPath)
if err != nil {
log.Error(ctx, "Error reading dir", "path", dirPath, err)
return
}
for _, f := range files {
isDir, err := isDirOrSymlinkToDir(dirPath, f)
// Skip invalid symlinks
if err != nil {
continue
}
if isDir && !isDirIgnored(dirPath, f) && isDirReadable(dirPath, f) {
children = append(children, filepath.Join(dirPath, f.Name()))
} else {
if f.ModTime().After(lastUpdated) {
lastUpdated = f.ModTime()
}
}
}
return
}
func (s *changeDetector) loadMap(ctx context.Context, dirMap dirInfoMap, path string, since time.Time, maybe bool) error {
children, lastUpdated, err := s.loadDir(ctx, path)
if err != nil {
return err
}
maybe = maybe || lastUpdated.After(since)
for _, c := range children {
err := s.loadMap(ctx, dirMap, c, since, maybe)
if err != nil {
return err
}
}
dir := s.getRelativePath(path)
dirMap[dir] = dirInfo{mdate: lastUpdated, maybe: maybe}
return nil
}
func (s *changeDetector) getRelativePath(subFolder string) string {
dir, _ := filepath.Rel(s.rootFolder, subFolder)
if dir == "" {
dir = "."
}
return dir
}
func (s *changeDetector) checkForUpdates(lastModifiedSince time.Time, newMap dirInfoMap) (changed []string, deleted []string, err error) {
for dir, newEntry := range newMap {
lastUpdated := newEntry.mdate
oldLastUpdated := lastModifiedSince
if oldEntry, ok := s.dirMap[dir]; ok {
oldLastUpdated = oldEntry.mdate
} else {
if newEntry.maybe {
oldLastUpdated = time.Time{}
}
}
if lastUpdated.After(oldLastUpdated) {
changed = append(changed, dir)
}
}
for dir := range s.dirMap {
if _, ok := newMap[dir]; !ok {
deleted = append(deleted, dir)
}
}
return
}