// scan scans the directory tree for files.
func (cache *Cache) scan() {
cache.cachedFiles = cmap.New()
cache.totalSize = 0
if !core.PathExists(cache.rootPath) {
if err := os.MkdirAll(cache.rootPath, core.DirPermissions); err != nil {
log.Fatalf("Failed to create cache directory %s: %s", cache.rootPath, err)
}
return
}
log.Info("Scanning cache directory %s...", cache.rootPath)
filepath.Walk(cache.rootPath, func(name string, info os.FileInfo, err error) error {
if err != nil {
log.Fatalf("%s", err)
} else if !info.IsDir() { // We don't have directory entries.
name = name[len(cache.rootPath)+1:]
log.Debug("Found file %s", name)
size := info.Size()
cache.cachedFiles.Set(name, &cachedFile{
lastReadTime: time.Unix(tools.AccessTime(info), 0),
readCount: 0,
size: size,
})
cache.totalSize += size
}
return nil
})
log.Info("Scan complete, found %d entries", cache.cachedFiles.Count())
}
func start(directory string, highWaterMark, lowWaterMark int64) {
entries := CacheEntries{}
var totalSize int64 = 0
if err := filepath.Walk(directory, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
} else if (len(info.Name()) == 28 || len(info.Name()) == 29) && info.Name()[27] == '=' {
// Directory has the right length. We do this in an attempt to clean only entire
// entries in the cache, not just individual files from them.
// 28 == length of 20-byte sha1 hash, encoded to base64, which always gets a trailing =
// as padding so we can check that to be "sure".
// Also 29 in case we appended an extra = (see below)
if size, err := findSize(path); err != nil {
return err
} else {
entries = append(entries, CacheEntry{path, size, tools.AccessTime(info)})
totalSize += size
return filepath.SkipDir
}
} else {
return nil // nothing particularly to do for other entries
}
}); err != nil {
log.Fatalf("error walking cache directory: %s\n", err)
}
log.Notice("Total cache size: %s", humanize.Bytes(uint64(totalSize)))
if totalSize < highWaterMark {
return // Nothing to do, cache is small enough.
}
// OK, we need to slim it down a bit. We implement a simple LRU algorithm.
sort.Sort(entries)
for _, entry := range entries {
log.Notice("Cleaning %s, accessed %s, saves %s", entry.Path, humanize.Time(time.Unix(entry.Atime, 0)), humanize.Bytes(uint64(entry.Size)))
// Try to rename the directory first so we don't delete bits while someone might access them.
newPath := entry.Path + "="
if err := os.Rename(entry.Path, newPath); err != nil {
log.Errorf("Couldn't rename %s: %s", entry.Path, err)
continue
}
if err := os.RemoveAll(newPath); err != nil {
log.Errorf("Couldn't remove %s: %s", newPath, err)
continue
}
totalSize -= entry.Size
if totalSize < lowWaterMark {
break
}
}
}