// updateGlobal adds this device+version to the version list for the given
// file. If the device is already present in the list, the version is updated.
// If the file does not have an entry in the global list, it is created.
func (t readWriteTransaction) updateGlobal(folder, device []byte, file protocol.FileInfo, globalSize *sizeTracker) bool {
l.Debugf("update global; folder=%q device=%v file=%q version=%d", folder, protocol.DeviceIDFromBytes(device), file.Name, file.Version)
name := []byte(file.Name)
gk := t.db.globalKey(folder, name)
svl, err := t.Get(gk, nil)
if err != nil && err != leveldb.ErrNotFound {
panic(err)
}
var fl versionList
var oldFile protocol.FileInfo
var hasOldFile bool
// Remove the device from the current version list
if svl != nil {
err = fl.UnmarshalXDR(svl)
if err != nil {
panic(err)
}
for i := range fl.versions {
if bytes.Compare(fl.versions[i].device, device) == 0 {
if fl.versions[i].version.Equal(file.Version) {
// No need to do anything
return false
}
if i == 0 {
// Keep the current newest file around so we can subtract it from
// the globalSize if we replace it.
oldFile, hasOldFile = t.getFile(folder, fl.versions[0].device, name)
}
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
}
nv := fileVersion{
device: device,
version: file.Version,
}
insertedAt := -1
// Find a position in the list to insert this file. The file at the front
// of the list is the newer, the "global".
for i := range fl.versions {
switch fl.versions[i].version.Compare(file.Version) {
case protocol.Equal, protocol.Lesser:
// The version at this point in the list is equal to or lesser
// ("older") than us. We insert ourselves in front of it.
fl.versions = insertVersion(fl.versions, i, nv)
insertedAt = i
goto done
case protocol.ConcurrentLesser, protocol.ConcurrentGreater:
// The version at this point is in conflict with us. We must pull
// the actual file metadata to determine who wins. If we win, we
// insert ourselves in front of the loser here. (The "Lesser" and
// "Greater" in the condition above is just based on the device
// IDs in the version vector, which is not the only thing we use
// to determine the winner.)
of, ok := t.getFile(folder, fl.versions[i].device, name)
if !ok {
panic("file referenced in version list does not exist")
}
if file.WinsConflict(of) {
fl.versions = insertVersion(fl.versions, i, nv)
insertedAt = i
goto done
}
}
}
// We didn't find a position for an insert above, so append to the end.
fl.versions = append(fl.versions, nv)
insertedAt = len(fl.versions) - 1
done:
if insertedAt == 0 {
// We just inserted a new newest version. Fixup the global size
// calculation.
if !file.Version.Equal(oldFile.Version) {
globalSize.addFile(file)
if hasOldFile {
// We have the old file that was removed at the head of the list.
globalSize.removeFile(oldFile)
} else if len(fl.versions) > 1 {
// The previous newest version is now at index 1, grab it from there.
oldFile, ok := t.getFile(folder, fl.versions[1].device, name)
if !ok {
panic("file referenced in version list does not exist")
}
globalSize.removeFile(oldFile)
}
}
}
l.Debugf("new global after update: %v", fl)
t.Put(gk, fl.MustMarshalXDR())
return true
}
