You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
332 lines
6.6 KiB
332 lines
6.6 KiB
package db
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"sync"
|
|
)
|
|
|
|
// IteratePrefix is a convenience function for iterating over a key domain
|
|
// restricted by prefix.
|
|
func IteratePrefix(db DB, prefix []byte) Iterator {
|
|
var start, end []byte
|
|
if len(prefix) == 0 {
|
|
start = nil
|
|
end = nil
|
|
} else {
|
|
start = cp(prefix)
|
|
end = cpIncr(prefix)
|
|
}
|
|
return db.Iterator(start, end)
|
|
}
|
|
|
|
/*
|
|
TODO: Make test, maybe rename.
|
|
// Like IteratePrefix but the iterator strips the prefix from the keys.
|
|
func IteratePrefixStripped(db DB, prefix []byte) Iterator {
|
|
start, end := ...
|
|
return newPrefixIterator(prefix, start, end, IteratePrefix(db, prefix))
|
|
}
|
|
*/
|
|
|
|
//----------------------------------------
|
|
// prefixDB
|
|
|
|
type prefixDB struct {
|
|
mtx sync.Mutex
|
|
prefix []byte
|
|
db DB
|
|
}
|
|
|
|
// NewPrefixDB lets you namespace multiple DBs within a single DB.
|
|
func NewPrefixDB(db DB, prefix []byte) *prefixDB {
|
|
return &prefixDB{
|
|
prefix: prefix,
|
|
db: db,
|
|
}
|
|
}
|
|
|
|
// Implements atomicSetDeleter.
|
|
func (pdb *prefixDB) Mutex() *sync.Mutex {
|
|
return &(pdb.mtx)
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Get(key []byte) []byte {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
pkey := pdb.prefixed(key)
|
|
value := pdb.db.Get(pkey)
|
|
return value
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Has(key []byte) bool {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
return pdb.db.Has(pdb.prefixed(key))
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Set(key []byte, value []byte) {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
pkey := pdb.prefixed(key)
|
|
pdb.db.Set(pkey, value)
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) SetSync(key []byte, value []byte) {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
pdb.db.SetSync(pdb.prefixed(key), value)
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Delete(key []byte) {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
pdb.db.Delete(pdb.prefixed(key))
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) DeleteSync(key []byte) {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
pdb.db.DeleteSync(pdb.prefixed(key))
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Iterator(start, end []byte) Iterator {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
var pstart, pend []byte
|
|
pstart = append(cp(pdb.prefix), start...)
|
|
if end == nil {
|
|
pend = cpIncr(pdb.prefix)
|
|
} else {
|
|
pend = append(cp(pdb.prefix), end...)
|
|
}
|
|
return newPrefixIterator(
|
|
pdb.prefix,
|
|
start,
|
|
end,
|
|
pdb.db.Iterator(
|
|
pstart,
|
|
pend,
|
|
),
|
|
)
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) ReverseIterator(start, end []byte) Iterator {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
var pstart, pend []byte
|
|
pstart = append(cp(pdb.prefix), start...)
|
|
if end == nil {
|
|
pend = cpIncr(pdb.prefix)
|
|
} else {
|
|
pend = append(cp(pdb.prefix), end...)
|
|
}
|
|
ritr := pdb.db.ReverseIterator(pstart, pend)
|
|
return newPrefixIterator(
|
|
pdb.prefix,
|
|
start,
|
|
end,
|
|
ritr,
|
|
)
|
|
}
|
|
|
|
// Implements DB.
|
|
// Panics if the underlying DB is not an
|
|
// atomicSetDeleter.
|
|
func (pdb *prefixDB) NewBatch() Batch {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
return newPrefixBatch(pdb.prefix, pdb.db.NewBatch())
|
|
}
|
|
|
|
/* NOTE: Uncomment to use memBatch instead of prefixBatch
|
|
// Implements atomicSetDeleter.
|
|
func (pdb *prefixDB) SetNoLock(key []byte, value []byte) {
|
|
pdb.db.(atomicSetDeleter).SetNoLock(pdb.prefixed(key), value)
|
|
}
|
|
|
|
// Implements atomicSetDeleter.
|
|
func (pdb *prefixDB) SetNoLockSync(key []byte, value []byte) {
|
|
pdb.db.(atomicSetDeleter).SetNoLockSync(pdb.prefixed(key), value)
|
|
}
|
|
|
|
// Implements atomicSetDeleter.
|
|
func (pdb *prefixDB) DeleteNoLock(key []byte) {
|
|
pdb.db.(atomicSetDeleter).DeleteNoLock(pdb.prefixed(key))
|
|
}
|
|
|
|
// Implements atomicSetDeleter.
|
|
func (pdb *prefixDB) DeleteNoLockSync(key []byte) {
|
|
pdb.db.(atomicSetDeleter).DeleteNoLockSync(pdb.prefixed(key))
|
|
}
|
|
*/
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Close() {
|
|
pdb.mtx.Lock()
|
|
defer pdb.mtx.Unlock()
|
|
|
|
pdb.db.Close()
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Print() {
|
|
fmt.Printf("prefix: %X\n", pdb.prefix)
|
|
|
|
itr := pdb.Iterator(nil, nil)
|
|
defer itr.Close()
|
|
for ; itr.Valid(); itr.Next() {
|
|
key := itr.Key()
|
|
value := itr.Value()
|
|
fmt.Printf("[%X]:\t[%X]\n", key, value)
|
|
}
|
|
}
|
|
|
|
// Implements DB.
|
|
func (pdb *prefixDB) Stats() map[string]string {
|
|
stats := make(map[string]string)
|
|
stats["prefixdb.prefix.string"] = string(pdb.prefix)
|
|
stats["prefixdb.prefix.hex"] = fmt.Sprintf("%X", pdb.prefix)
|
|
source := pdb.db.Stats()
|
|
for key, value := range source {
|
|
stats["prefixdb.source."+key] = value
|
|
}
|
|
return stats
|
|
}
|
|
|
|
func (pdb *prefixDB) prefixed(key []byte) []byte {
|
|
return append(cp(pdb.prefix), key...)
|
|
}
|
|
|
|
//----------------------------------------
|
|
// prefixBatch
|
|
|
|
type prefixBatch struct {
|
|
prefix []byte
|
|
source Batch
|
|
}
|
|
|
|
func newPrefixBatch(prefix []byte, source Batch) prefixBatch {
|
|
return prefixBatch{
|
|
prefix: prefix,
|
|
source: source,
|
|
}
|
|
}
|
|
|
|
func (pb prefixBatch) Set(key, value []byte) {
|
|
pkey := append(cp(pb.prefix), key...)
|
|
pb.source.Set(pkey, value)
|
|
}
|
|
|
|
func (pb prefixBatch) Delete(key []byte) {
|
|
pkey := append(cp(pb.prefix), key...)
|
|
pb.source.Delete(pkey)
|
|
}
|
|
|
|
func (pb prefixBatch) Write() {
|
|
pb.source.Write()
|
|
}
|
|
|
|
func (pb prefixBatch) WriteSync() {
|
|
pb.source.WriteSync()
|
|
}
|
|
|
|
//----------------------------------------
|
|
// prefixIterator
|
|
|
|
var _ Iterator = (*prefixIterator)(nil)
|
|
|
|
// Strips prefix while iterating from Iterator.
|
|
type prefixIterator struct {
|
|
prefix []byte
|
|
start []byte
|
|
end []byte
|
|
source Iterator
|
|
valid bool
|
|
}
|
|
|
|
func newPrefixIterator(prefix, start, end []byte, source Iterator) *prefixIterator {
|
|
if !source.Valid() || !bytes.HasPrefix(source.Key(), prefix) {
|
|
return &prefixIterator{
|
|
prefix: prefix,
|
|
start: start,
|
|
end: end,
|
|
source: source,
|
|
valid: false,
|
|
}
|
|
} else {
|
|
return &prefixIterator{
|
|
prefix: prefix,
|
|
start: start,
|
|
end: end,
|
|
source: source,
|
|
valid: true,
|
|
}
|
|
}
|
|
}
|
|
|
|
func (itr *prefixIterator) Domain() (start []byte, end []byte) {
|
|
return itr.start, itr.end
|
|
}
|
|
|
|
func (itr *prefixIterator) Valid() bool {
|
|
return itr.valid && itr.source.Valid()
|
|
}
|
|
|
|
func (itr *prefixIterator) Next() {
|
|
if !itr.valid {
|
|
panic("prefixIterator invalid, cannot call Next()")
|
|
}
|
|
itr.source.Next()
|
|
if !itr.source.Valid() || !bytes.HasPrefix(itr.source.Key(), itr.prefix) {
|
|
itr.valid = false
|
|
return
|
|
}
|
|
}
|
|
|
|
func (itr *prefixIterator) Key() (key []byte) {
|
|
if !itr.valid {
|
|
panic("prefixIterator invalid, cannot call Key()")
|
|
}
|
|
return stripPrefix(itr.source.Key(), itr.prefix)
|
|
}
|
|
|
|
func (itr *prefixIterator) Value() (value []byte) {
|
|
if !itr.valid {
|
|
panic("prefixIterator invalid, cannot call Value()")
|
|
}
|
|
return itr.source.Value()
|
|
}
|
|
|
|
func (itr *prefixIterator) Close() {
|
|
itr.source.Close()
|
|
}
|
|
|
|
//----------------------------------------
|
|
|
|
func stripPrefix(key []byte, prefix []byte) (stripped []byte) {
|
|
if len(key) < len(prefix) {
|
|
panic("should not happen")
|
|
}
|
|
if !bytes.Equal(key[:len(prefix)], prefix) {
|
|
panic("should not happne")
|
|
}
|
|
return key[len(prefix):]
|
|
}
|