func collate(a, b []byte) (r int) {
da, err := lldb.DecodeScalars(a)
if err != nil {
panic(err)
}
db, err := lldb.DecodeScalars(b)
if err != nil {
panic(err)
}
r, err = lldb.Collate(da, db, nil)
if err != nil {
panic(err)
}
return
}
// Do calls f for every subscripts-value pair in s in ascending collation order
// of the subscripts. Do returns non nil error for general errors (eg. file
// read error). If f returns false or a non nil error then Do terminates and
// returns the value of error from f.
//
// Note: f can get called with a subscripts-value pair which actually may no
// longer exist - if some other goroutine introduces such data race.
// Coordination required to avoid this situation, if applicable/desirable, must
// be provided by the client of dbm.
func (s *Slice) Do(f func(subscripts, value []interface{}) (bool, error)) (err error) {
var (
db = s.a.db
noVal bool
)
if err = db.enter(); err != nil {
return
}
doLeave := true
defer func() {
if doLeave {
db.leave(&err)
}
}()
ok, err := s.a.validate(false)
if !ok {
return err
}
tree := s.a.tree
if !tree.IsMem() && tree.Handle() == 1 {
noVal = true
}
switch {
case s.from == nil && s.to == nil:
bprefix, err := lldb.EncodeScalars(s.prefix...)
if err != nil {
return err
}
enum, _, err := tree.Seek(bprefix)
if err != nil {
return noEof(err)
}
for {
bk, bv, err := enum.Next()
if err != nil {
return noEof(err)
}
k, err := lldb.DecodeScalars(bk)
if err != nil {
return noEof(err)
}
if n := len(s.prefix); n != 0 {
if len(k) < len(s.prefix) {
return nil
}
c, err := lldb.Collate(k[:n], s.prefix, nil)
if err != nil {
return err
}
if c > 0 {
return nil
}
}
v, err := lldb.DecodeScalars(bv)
if err != nil {
return err
}
doLeave = false
if db.leave(&err) != nil {
return err
}
if noVal && v != nil {
v = []interface{}{0}
}
if more, err := f(k[len(s.prefix):], v); !more || err != nil {
return noEof(err)
}
if err = db.enter(); err != nil {
return err
}
doLeave = true
}
case s.from == nil && s.to != nil:
bprefix, err := lldb.EncodeScalars(s.prefix...)
if err != nil {
return err
}
enum, _, err := tree.Seek(bprefix)
if err != nil {
return noEof(err)
}
to := append(append([]interface{}(nil), s.prefix...), s.to...)
for {
bk, bv, err := enum.Next()
if err != nil {
return noEof(err)
}
k, err := lldb.DecodeScalars(bk)
if err != nil {
return err
}
c, err := lldb.Collate(k, to, nil)
if err != nil {
return err
}
if c > 0 {
return err
}
v, err := lldb.DecodeScalars(bv)
if err != nil {
return noEof(err)
}
doLeave = false
if db.leave(&err) != nil {
return err
}
if noVal && v != nil {
v = []interface{}{0}
}
if more, err := f(k[len(s.prefix):], v); !more || err != nil {
return noEof(err)
}
if err = db.enter(); err != nil {
return err
}
doLeave = true
}
case s.from != nil && s.to == nil:
bprefix, err := lldb.EncodeScalars(append(s.prefix, s.from...)...)
if err != nil {
return err
}
enum, _, err := tree.Seek(bprefix)
if err != nil {
return noEof(err)
}
for {
bk, bv, err := enum.Next()
if err != nil {
return noEof(err)
}
k, err := lldb.DecodeScalars(bk)
if err != nil {
return noEof(err)
}
if n := len(s.prefix); n != 0 {
if len(k) < len(s.prefix) {
return nil
}
c, err := lldb.Collate(k[:n], s.prefix, nil)
if err != nil {
return err
}
if c > 0 {
return nil
}
}
v, err := lldb.DecodeScalars(bv)
if err != nil {
return err
}
doLeave = false
if db.leave(&err) != nil {
return err
}
if noVal && v != nil {
v = []interface{}{0}
}
if more, err := f(k[len(s.prefix):], v); !more || err != nil {
return noEof(err)
}
if err = db.enter(); err != nil {
return err
}
doLeave = true
}
case s.from != nil && s.to != nil:
bprefix, err := lldb.EncodeScalars(append(s.prefix, s.from...)...)
if err != nil {
return err
}
enum, _, err := tree.Seek(bprefix)
if err != nil {
return noEof(err)
}
to := append(append([]interface{}(nil), s.prefix...), s.to...)
for {
bk, bv, err := enum.Next()
if err != nil {
return noEof(err)
}
k, err := lldb.DecodeScalars(bk)
if err != nil {
return noEof(err)
}
c, err := lldb.Collate(k, to, nil)
if err != nil {
return err
}
if c > 0 {
return err
}
v, err := lldb.DecodeScalars(bv)
if err != nil {
return err
}
doLeave = false
if db.leave(&err) != nil {
return err
}
if noVal && v != nil {
v = []interface{}{0}
}
if more, err := f(k[len(s.prefix):], v); !more || err != nil {
return noEof(err)
}
if err = db.enter(); err != nil {
return err
}
doLeave = true
}
default:
panic("slice.go: internal error")
}
}