Don Newton | 379ae25 | 2019-04-01 12:17:06 -0400 | [diff] [blame^] | 1 | // Copyright (C) MongoDB, Inc. 2017-present. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| 4 | // not use this file except in compliance with the License. You may obtain |
| 5 | // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| 6 | |
| 7 | package mongo |
| 8 | |
| 9 | import ( |
| 10 | "context" |
| 11 | "errors" |
| 12 | "fmt" |
| 13 | "net" |
| 14 | "reflect" |
| 15 | "strings" |
| 16 | |
| 17 | "github.com/mongodb/mongo-go-driver/mongo/options" |
| 18 | "github.com/mongodb/mongo-go-driver/x/bsonx" |
| 19 | |
| 20 | "github.com/mongodb/mongo-go-driver/bson" |
| 21 | "github.com/mongodb/mongo-go-driver/bson/bsoncodec" |
| 22 | "github.com/mongodb/mongo-go-driver/bson/bsontype" |
| 23 | "github.com/mongodb/mongo-go-driver/bson/primitive" |
| 24 | ) |
| 25 | |
| 26 | // Dialer is used to make network connections. |
| 27 | type Dialer interface { |
| 28 | DialContext(ctx context.Context, network, address string) (net.Conn, error) |
| 29 | } |
| 30 | |
| 31 | // BSONAppender is an interface implemented by types that can marshal a |
| 32 | // provided type into BSON bytes and append those bytes to the provided []byte. |
| 33 | // The AppendBSON can return a non-nil error and non-nil []byte. The AppendBSON |
| 34 | // method may also write incomplete BSON to the []byte. |
| 35 | type BSONAppender interface { |
| 36 | AppendBSON([]byte, interface{}) ([]byte, error) |
| 37 | } |
| 38 | |
| 39 | // BSONAppenderFunc is an adapter function that allows any function that |
| 40 | // satisfies the AppendBSON method signature to be used where a BSONAppender is |
| 41 | // used. |
| 42 | type BSONAppenderFunc func([]byte, interface{}) ([]byte, error) |
| 43 | |
| 44 | // AppendBSON implements the BSONAppender interface |
| 45 | func (baf BSONAppenderFunc) AppendBSON(dst []byte, val interface{}) ([]byte, error) { |
| 46 | return baf(dst, val) |
| 47 | } |
| 48 | |
| 49 | // MarshalError is returned when attempting to transform a value into a document |
| 50 | // results in an error. |
| 51 | type MarshalError struct { |
| 52 | Value interface{} |
| 53 | Err error |
| 54 | } |
| 55 | |
| 56 | // Error implements the error interface. |
| 57 | func (me MarshalError) Error() string { |
| 58 | return fmt.Sprintf("cannot transform type %s to a *bsonx.Document", reflect.TypeOf(me.Value)) |
| 59 | } |
| 60 | |
| 61 | // Pipeline is a type that makes creating aggregation pipelines easier. It is a |
| 62 | // helper and is intended for serializing to BSON. |
| 63 | // |
| 64 | // Example usage: |
| 65 | // |
| 66 | // mongo.Pipeline{ |
| 67 | // {{"$group", bson.D{{"_id", "$state"}, {"totalPop", bson.D{{"$sum", "$pop"}}}}}}, |
| 68 | // {{"$match", bson.D{{"totalPop", bson.D{{"$gte", 10*1000*1000}}}}}}, |
| 69 | // } |
| 70 | // |
| 71 | type Pipeline []bson.D |
| 72 | |
| 73 | // transformAndEnsureID is a hack that makes it easy to get a RawValue as the _id value. This will |
| 74 | // be removed when we switch from using bsonx to bsoncore for the driver package. |
| 75 | func transformAndEnsureID(registry *bsoncodec.Registry, val interface{}) (bsonx.Doc, interface{}, error) { |
| 76 | // TODO: performance is going to be pretty bad for bsonx.Doc here since we turn it into a []byte |
| 77 | // only to turn it back into a bsonx.Doc. We can fix this post beta1 when we refactor the driver |
| 78 | // package to use bsoncore.Document instead of bsonx.Doc. |
| 79 | if registry == nil { |
| 80 | registry = bson.NewRegistryBuilder().Build() |
| 81 | } |
| 82 | switch tt := val.(type) { |
| 83 | case nil: |
| 84 | return nil, nil, ErrNilDocument |
| 85 | case bsonx.Doc: |
| 86 | val = tt.Copy() |
| 87 | case []byte: |
| 88 | // Slight optimization so we'll just use MarshalBSON and not go through the codec machinery. |
| 89 | val = bson.Raw(tt) |
| 90 | } |
| 91 | |
| 92 | // TODO(skriptble): Use a pool of these instead. |
| 93 | buf := make([]byte, 0, 256) |
| 94 | b, err := bson.MarshalAppendWithRegistry(registry, buf, val) |
| 95 | if err != nil { |
| 96 | return nil, nil, MarshalError{Value: val, Err: err} |
| 97 | } |
| 98 | |
| 99 | d, err := bsonx.ReadDoc(b) |
| 100 | if err != nil { |
| 101 | return nil, nil, err |
| 102 | } |
| 103 | |
| 104 | var id interface{} |
| 105 | |
| 106 | idx := d.IndexOf("_id") |
| 107 | var idElem bsonx.Elem |
| 108 | switch idx { |
| 109 | case -1: |
| 110 | idElem = bsonx.Elem{"_id", bsonx.ObjectID(primitive.NewObjectID())} |
| 111 | d = append(d, bsonx.Elem{}) |
| 112 | copy(d[1:], d) |
| 113 | d[0] = idElem |
| 114 | default: |
| 115 | idElem = d[idx] |
| 116 | copy(d[1:idx+1], d[0:idx]) |
| 117 | d[0] = idElem |
| 118 | } |
| 119 | |
| 120 | t, data, err := idElem.Value.MarshalAppendBSONValue(buf[:0]) |
| 121 | if err != nil { |
| 122 | return nil, nil, err |
| 123 | } |
| 124 | |
| 125 | err = bson.RawValue{Type: t, Value: data}.UnmarshalWithRegistry(registry, &id) |
| 126 | if err != nil { |
| 127 | return nil, nil, err |
| 128 | } |
| 129 | |
| 130 | return d, id, nil |
| 131 | } |
| 132 | |
| 133 | func transformDocument(registry *bsoncodec.Registry, val interface{}) (bsonx.Doc, error) { |
| 134 | if registry == nil { |
| 135 | registry = bson.NewRegistryBuilder().Build() |
| 136 | } |
| 137 | if val == nil { |
| 138 | return nil, ErrNilDocument |
| 139 | } |
| 140 | if doc, ok := val.(bsonx.Doc); ok { |
| 141 | return doc.Copy(), nil |
| 142 | } |
| 143 | if bs, ok := val.([]byte); ok { |
| 144 | // Slight optimization so we'll just use MarshalBSON and not go through the codec machinery. |
| 145 | val = bson.Raw(bs) |
| 146 | } |
| 147 | |
| 148 | // TODO(skriptble): Use a pool of these instead. |
| 149 | buf := make([]byte, 0, 256) |
| 150 | b, err := bson.MarshalAppendWithRegistry(registry, buf[:0], val) |
| 151 | if err != nil { |
| 152 | return nil, MarshalError{Value: val, Err: err} |
| 153 | } |
| 154 | return bsonx.ReadDoc(b) |
| 155 | } |
| 156 | |
| 157 | func ensureID(d bsonx.Doc) (bsonx.Doc, interface{}) { |
| 158 | var id interface{} |
| 159 | |
| 160 | elem, err := d.LookupElementErr("_id") |
| 161 | switch err.(type) { |
| 162 | case nil: |
| 163 | id = elem |
| 164 | default: |
| 165 | oid := primitive.NewObjectID() |
| 166 | d = append(d, bsonx.Elem{"_id", bsonx.ObjectID(oid)}) |
| 167 | id = oid |
| 168 | } |
| 169 | return d, id |
| 170 | } |
| 171 | |
| 172 | func ensureDollarKey(doc bsonx.Doc) error { |
| 173 | if len(doc) == 0 { |
| 174 | return errors.New("update document must have at least one element") |
| 175 | } |
| 176 | if !strings.HasPrefix(doc[0].Key, "$") { |
| 177 | return errors.New("update document must contain key beginning with '$'") |
| 178 | } |
| 179 | return nil |
| 180 | } |
| 181 | |
| 182 | func transformAggregatePipeline(registry *bsoncodec.Registry, pipeline interface{}) (bsonx.Arr, error) { |
| 183 | pipelineArr := bsonx.Arr{} |
| 184 | switch t := pipeline.(type) { |
| 185 | case bsoncodec.ValueMarshaler: |
| 186 | btype, val, err := t.MarshalBSONValue() |
| 187 | if err != nil { |
| 188 | return nil, err |
| 189 | } |
| 190 | if btype != bsontype.Array { |
| 191 | return nil, fmt.Errorf("ValueMarshaler returned a %v, but was expecting %v", btype, bsontype.Array) |
| 192 | } |
| 193 | err = pipelineArr.UnmarshalBSONValue(btype, val) |
| 194 | if err != nil { |
| 195 | return nil, err |
| 196 | } |
| 197 | default: |
| 198 | val := reflect.ValueOf(t) |
| 199 | if !val.IsValid() || (val.Kind() != reflect.Slice && val.Kind() != reflect.Array) { |
| 200 | return nil, fmt.Errorf("can only transform slices and arrays into aggregation pipelines, but got %v", val.Kind()) |
| 201 | } |
| 202 | for idx := 0; idx < val.Len(); idx++ { |
| 203 | elem, err := transformDocument(registry, val.Index(idx).Interface()) |
| 204 | if err != nil { |
| 205 | return nil, err |
| 206 | } |
| 207 | pipelineArr = append(pipelineArr, bsonx.Document(elem)) |
| 208 | } |
| 209 | } |
| 210 | |
| 211 | return pipelineArr, nil |
| 212 | } |
| 213 | |
| 214 | // Build the aggregation pipeline for the CountDocument command. |
| 215 | func countDocumentsAggregatePipeline(registry *bsoncodec.Registry, filter interface{}, opts *options.CountOptions) (bsonx.Arr, error) { |
| 216 | pipeline := bsonx.Arr{} |
| 217 | filterDoc, err := transformDocument(registry, filter) |
| 218 | |
| 219 | if err != nil { |
| 220 | return nil, err |
| 221 | } |
| 222 | pipeline = append(pipeline, bsonx.Document(bsonx.Doc{{"$match", bsonx.Document(filterDoc)}})) |
| 223 | |
| 224 | if opts != nil { |
| 225 | if opts.Skip != nil { |
| 226 | pipeline = append(pipeline, bsonx.Document(bsonx.Doc{{"$skip", bsonx.Int64(*opts.Skip)}})) |
| 227 | } |
| 228 | if opts.Limit != nil { |
| 229 | pipeline = append(pipeline, bsonx.Document(bsonx.Doc{{"$limit", bsonx.Int64(*opts.Limit)}})) |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | pipeline = append(pipeline, bsonx.Document(bsonx.Doc{ |
| 234 | {"$group", bsonx.Document(bsonx.Doc{ |
| 235 | {"_id", bsonx.Null()}, |
| 236 | {"n", bsonx.Document(bsonx.Doc{{"$sum", bsonx.Int32(1)}})}, |
| 237 | })}, |
| 238 | }, |
| 239 | )) |
| 240 | |
| 241 | return pipeline, nil |
| 242 | } |