vitess.io/vitess@v0.16.2/go/vt/vtgate/vindexes/binary.go (about) 1 /* 2 Copyright 2019 The Vitess Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package vindexes 18 19 import ( 20 "bytes" 21 "context" 22 "fmt" 23 24 "vitess.io/vitess/go/sqltypes" 25 "vitess.io/vitess/go/vt/key" 26 ) 27 28 var ( 29 _ SingleColumn = (*Binary)(nil) 30 _ Reversible = (*Binary)(nil) 31 _ Hashing = (*Binary)(nil) 32 ) 33 34 // Binary is a vindex that converts binary bits to a keyspace id. 35 type Binary struct { 36 name string 37 } 38 39 // NewBinary creates a new Binary. 40 func NewBinary(name string, _ map[string]string) (Vindex, error) { 41 return &Binary{name: name}, nil 42 } 43 44 // String returns the name of the vindex. 45 func (vind *Binary) String() string { 46 return vind.name 47 } 48 49 // Cost returns the cost as 1. 50 func (vind *Binary) Cost() int { 51 return 0 52 } 53 54 // IsUnique returns true since the Vindex is unique. 55 func (vind *Binary) IsUnique() bool { 56 return true 57 } 58 59 // NeedsVCursor satisfies the Vindex interface. 60 func (vind *Binary) NeedsVCursor() bool { 61 return false 62 } 63 64 // Verify returns true if ids maps to ksids. 65 func (vind *Binary) Verify(ctx context.Context, vcursor VCursor, ids []sqltypes.Value, ksids [][]byte) ([]bool, error) { 66 out := make([]bool, 0, len(ids)) 67 for i, id := range ids { 68 idBytes, err := vind.Hash(id) 69 if err != nil { 70 return out, err 71 } 72 out = append(out, bytes.Equal(idBytes, ksids[i])) 73 } 74 return out, nil 75 } 76 77 // Map can map ids to key.Destination objects. 78 func (vind *Binary) Map(ctx context.Context, vcursor VCursor, ids []sqltypes.Value) ([]key.Destination, error) { 79 out := make([]key.Destination, 0, len(ids)) 80 for _, id := range ids { 81 idBytes, err := vind.Hash(id) 82 if err != nil { 83 return out, err 84 } 85 out = append(out, key.DestinationKeyspaceID(idBytes)) 86 } 87 return out, nil 88 } 89 90 func (vind *Binary) Hash(id sqltypes.Value) ([]byte, error) { 91 return id.ToBytes() 92 } 93 94 // ReverseMap returns the associated ids for the ksids. 95 func (*Binary) ReverseMap(_ VCursor, ksids [][]byte) ([]sqltypes.Value, error) { 96 var reverseIds = make([]sqltypes.Value, len(ksids)) 97 for rownum, keyspaceID := range ksids { 98 if keyspaceID == nil { 99 return nil, fmt.Errorf("Binary.ReverseMap: keyspaceId is nil") 100 } 101 reverseIds[rownum] = sqltypes.MakeTrusted(sqltypes.VarBinary, keyspaceID) 102 } 103 return reverseIds, nil 104 } 105 106 func init() { 107 Register("binary", NewBinary) 108 }