add slice for store, optimize leveldb/rocksdb get

store/boltdb/db.go

@@ -167,6 +167,15 @@ func (db *DB) Compact() error {
 	return nil
 }
 
+func (db *DB) GetSlice(key []byte) (driver.ISlice, error) {
+	v, err := db.Get(key)
+	if err != nil {
+		return nil, err
+	} else {
+		return driver.GoSlice(v), nil
+	}
+}
+
 func init() {
 	driver.Register(Store{})
 }

store/driver/driver.go

@@ -12,6 +12,7 @@ type IDB interface {
 	Close() error
 
 	Get(key []byte) ([]byte, error)
+	GetSlice(key []byte) (ISlice, error)
 
 	Put(key []byte, value []byte) error
 	Delete(key []byte) error

store/driver/slice.go

@@ -0,0 +1,60 @@
+package driver
+
+// #include <stdlib.h>
+import "C"
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+type ISlice interface {
+	Data() []byte
+	Size() int
+	Free()
+}
+
+type CSlice struct {
+	data unsafe.Pointer
+	size int
+}
+
+func NewCSlice(p unsafe.Pointer, n int) *CSlice {
+	return &CSlice{p, n}
+}
+
+func (s *CSlice) Data() []byte {
+	var value []byte
+
+	sH := (*reflect.SliceHeader)(unsafe.Pointer(&value))
+	sH.Cap = int(s.size)
+	sH.Len = int(s.size)
+	sH.Data = uintptr(s.data)
+
+	return value
+}
+
+func (s *CSlice) Size() int {
+	return int(s.size)
+}
+
+func (s *CSlice) Free() {
+	if s.data != nil {
+		C.free(s.data)
+		s.data = nil
+	}
+}
+
+type GoSlice []byte
+
+func (s GoSlice) Data() []byte {
+	return []byte(s)
+}
+
+func (s GoSlice) Size() int {
+	return len(s)
+}
+
+func (s GoSlice) Free() {
+
+}

store/goleveldb/db.go

@@ -196,6 +196,14 @@ func (db *DB) Compact() error {
 	return db.db.CompactRange(util.Range{nil, nil})
 }
 
+func (db *DB) GetSlice(key []byte) (driver.ISlice, error) {
+	v, err := db.Get(key)
+	if err != nil {
+		return nil, err
+	} else {
+		return driver.GoSlice(v), nil
+	}
+}
 func init() {
 	driver.Register(Store{})
 	driver.Register(MemStore{})

store/leveldb/db.go

@@ -257,6 +257,28 @@ func (db *DB) get(ro *ReadOptions, key []byte) ([]byte, error) {
 	return C.GoBytes(unsafe.Pointer(value), C.int(vallen)), nil
 }
 
+func (db *DB) getSlice(ro *ReadOptions, key []byte) (driver.ISlice, error) {
+	var errStr *C.char
+	var vallen C.size_t
+	var k *C.char
+	if len(key) != 0 {
+		k = (*C.char)(unsafe.Pointer(&key[0]))
+	}
+
+	value := C.leveldb_get(
+		db.db, ro.Opt, k, C.size_t(len(key)), &vallen, &errStr)
+
+	if errStr != nil {
+		return nil, saveError(errStr)
+	}
+
+	if value == nil {
+		return nil, nil
+	}
+
+	return driver.NewCSlice(unsafe.Pointer(value), int(vallen)), nil
+}
+
 func (db *DB) delete(wo *WriteOptions, key []byte) error {
 	var errStr *C.char
 	var k *C.char
@@ -282,6 +304,10 @@ func (db *DB) Compact() error {
 	return nil
 }
 
+func (db *DB) GetSlice(key []byte) (driver.ISlice, error) {
+	return db.getSlice(db.readOpts, key)
+}
+
 func init() {
 	driver.Register(Store{})
 }

store/mdb/mdb.go

@@ -311,6 +311,15 @@ func (db MDB) Compact() error {
 	return nil
 }
 
+func (db MDB) GetSlice(key []byte) (driver.ISlice, error) {
+	v, err := db.Get(key)
+	if err != nil {
+		return nil, err
+	} else {
+		return driver.GoSlice(v), nil
+	}
+}
+
 func init() {
 	driver.Register(Store{})
 }

store/rocksdb/db.go

@@ -284,6 +284,28 @@ func (db *DB) get(ro *ReadOptions, key []byte) ([]byte, error) {
 	return C.GoBytes(unsafe.Pointer(value), C.int(vallen)), nil
 }
 
+func (db *DB) getSlice(ro *ReadOptions, key []byte) (driver.ISlice, error) {
+	var errStr *C.char
+	var vallen C.size_t
+	var k *C.char
+	if len(key) != 0 {
+		k = (*C.char)(unsafe.Pointer(&key[0]))
+	}
+
+	value := C.rocksdb_get(
+		db.db, ro.Opt, k, C.size_t(len(key)), &vallen, &errStr)
+
+	if errStr != nil {
+		return nil, saveError(errStr)
+	}
+
+	if value == nil {
+		return nil, nil
+	}
+
+	return driver.NewCSlice(unsafe.Pointer(value), int(vallen)), nil
+}
+
 func (db *DB) delete(wo *WriteOptions, key []byte) error {
 	var errStr *C.char
 	var k *C.char
@@ -309,6 +331,10 @@ func (db *DB) Compact() error {
 	return nil
 }
 
+func (db *DB) GetSlice(key []byte) (driver.ISlice, error) {
+	return db.getSlice(db.readOpts, key)
+}
+
 func init() {
 	driver.Register(Store{})
 }