// ldbUpdateGlobal 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 ldbUpdateGlobal(db dbReader, batch dbWriter, folder, device []byte, file protocol.FileInfo) bool {
if debugDB {
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 := globalKey(folder, name)
svl, err := db.Get(gk, nil)
if err != nil && err != leveldb.ErrNotFound {
panic(err)
}
var fl versionList
// 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
}
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
}
nv := fileVersion{
device: device,
version: file.Version,
}
// 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)
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 := ldbGet(db, 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)
goto done
}
}
}
// We didn't find a position for an insert above, so append to the end.
fl.versions = append(fl.versions, nv)
done:
if debugDB {
l.Debugf("batch.Put %p %x", batch, gk)
l.Debugf("new global after update: %v", fl)
}
batch.Put(gk, fl.MustMarshalXDR())
return true
}
