Esempio n. 1
0
// Scan returns up to max key/value objects starting from
// start (inclusive) and ending at end (non-inclusive).
// If max is zero then the number of key/values returned is unbounded.
func (r *RocksDB) Scan(start, end Key, max int64) ([]RawKeyValue, error) {
	var keyVals []RawKeyValue
	if bytes.Compare(start, end) >= 0 {
		return keyVals, nil
	}
	// In order to prevent content displacement, caching is disabled
	// when performing scans. Any options set within the shared read
	// options field that should be carried over needs to be set here
	// as well.
	opts := C.rocksdb_readoptions_create()
	C.rocksdb_readoptions_set_fill_cache(opts, 0)
	defer C.rocksdb_readoptions_destroy(opts)
	it := C.rocksdb_create_iterator(r.rdb, opts)
	defer C.rocksdb_iter_destroy(it)

	byteCount := len(start)
	if byteCount == 0 {
		// start=Key("") needs special treatment since we need
		// to access start[0] in an explicit seek.
		C.rocksdb_iter_seek_to_first(it)
	} else {
		C.rocksdb_iter_seek(it, bytesPointer(start), C.size_t(byteCount))
	}
	for i := int64(1); C.rocksdb_iter_valid(it) == 1; C.rocksdb_iter_next(it) {
		if max > 0 && i > max {
			break
		}
		var l C.size_t
		// The data returned by rocksdb_iter_{key,value} is not meant to be
		// freed by the client. It is a direct reference to the data managed
		// by the iterator, so it is copied instead of freed.
		data := C.rocksdb_iter_key(it, &l)
		k := C.GoBytes(unsafe.Pointer(data), C.int(l))
		if bytes.Compare(k, end) >= 0 {
			break
		}
		data = C.rocksdb_iter_value(it, &l)
		v := C.GoBytes(unsafe.Pointer(data), C.int(l))
		keyVals = append(keyVals, RawKeyValue{
			Key:   k,
			Value: v,
		})
		i++
	}
	// Check for any errors during iteration.
	var cErr *C.char
	C.rocksdb_iter_get_error(it, &cErr)
	if cErr != nil {
		return nil, charToErr(cErr)
	}
	return keyVals, nil
}
Esempio n. 2
0
// scan returns up to max key/value objects starting from
// start (inclusive) and ending at end (non-inclusive).
// If max is zero then the number of key/values returned is unbounded.
func (r *RocksDB) scan(start, end Key, max int64) ([]KeyValue, error) {
	// In order to prevent content displacement, caching is disabled
	// when performing scans. Any options set within the shared read
	// options field that should be carried over needs to be set here
	// as well.
	opts := C.rocksdb_readoptions_create()
	C.rocksdb_readoptions_set_fill_cache(opts, 0)
	defer C.rocksdb_readoptions_destroy(opts)
	it := C.rocksdb_create_iterator(r.rdb, opts)
	defer C.rocksdb_iter_destroy(it)

	keyVals := []KeyValue{}
	C.rocksdb_iter_seek(it, (*C.char)(unsafe.Pointer(&start[0])), C.size_t(len(start)))
	for i := int64(1); C.rocksdb_iter_valid(it) == 1; C.rocksdb_iter_next(it) {
		if max > 0 && i > max {
			break
		}
		var l C.size_t
		// The data returned by rocksdb_iter_{key,value} is not meant to be
		// freed by the client. It is a direct reference to the data managed
		// by the iterator, so it is copied instead of freed.
		data := C.rocksdb_iter_key(it, &l)
		k := C.GoBytes(unsafe.Pointer(data), C.int(l))
		if bytes.Equal(k, end) {
			break
		}
		data = C.rocksdb_iter_value(it, &l)
		v := C.GoBytes(unsafe.Pointer(data), C.int(l))
		keyVals = append(keyVals, KeyValue{
			Key:   k,
			Value: Value{Bytes: v},
		})
		i++
	}
	// Check for any errors during iteration.
	var cErr *C.char
	C.rocksdb_iter_get_error(it, &cErr)
	if cErr != nil {
		return nil, charToErr(cErr)
	}
	return keyVals, nil
}
Esempio n. 3
0
// Valid returns false only when an Iterator has iterated past either the
// first or the last key in the database.
func (it *Iterator) Valid() bool {
	return ucharToBool(C.rocksdb_iter_valid(it.Iter))
}
Esempio n. 4
0
// ValidForPrefix returns false only when an Iterator has iterated past the
// first or the last key in the database or the specified prefix.
func (i *Iterator) ValidForPrefix(prefix []byte) bool {
	return C.rocksdb_iter_valid(i.c) != 0 && bytes.HasPrefix(i.Key().Data(), prefix)
}
Esempio n. 5
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// Valid returns false only when an Iterator has iterated past either the
// first or the last key in the database.
func (i *Iterator) Valid() bool {
	return C.rocksdb_iter_valid(i.c) != 0
}
Esempio n. 6
0
// Valid returns false only when an Iterator has iterated past either the
// first or the last key in the database.
func (self *Iterator) Valid() bool {
	return C.rocksdb_iter_valid(self.c) != 0
}
Esempio n. 7
0
File: db.go Progetto: tradia/gotable
func (iter *Iterator) Valid() bool {
	return C.rocksdb_iter_valid(iter.it) != 0
}