| // Copyright (C) MongoDB, Inc. 2017-present. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| // not use this file except in compliance with the License. You may obtain |
| // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| |
| package command |
| |
| import ( |
| "context" |
| |
| "github.com/mongodb/mongo-go-driver/bson" |
| "github.com/mongodb/mongo-go-driver/mongo/readconcern" |
| "github.com/mongodb/mongo-go-driver/mongo/readpref" |
| "github.com/mongodb/mongo-go-driver/x/bsonx" |
| "github.com/mongodb/mongo-go-driver/x/mongo/driver/session" |
| "github.com/mongodb/mongo-go-driver/x/network/description" |
| "github.com/mongodb/mongo-go-driver/x/network/result" |
| "github.com/mongodb/mongo-go-driver/x/network/wiremessage" |
| ) |
| |
| // Distinct represents the disctinct command. |
| // |
| // The distinct command returns the distinct values for a specified field |
| // across a single collection. |
| type Distinct struct { |
| NS Namespace |
| Field string |
| Query bsonx.Doc |
| Opts []bsonx.Elem |
| ReadPref *readpref.ReadPref |
| ReadConcern *readconcern.ReadConcern |
| Clock *session.ClusterClock |
| Session *session.Client |
| |
| result result.Distinct |
| err error |
| } |
| |
| // Encode will encode this command into a wire message for the given server description. |
| func (d *Distinct) Encode(desc description.SelectedServer) (wiremessage.WireMessage, error) { |
| cmd, err := d.encode(desc) |
| if err != nil { |
| return nil, err |
| } |
| |
| return cmd.Encode(desc) |
| } |
| |
| // Encode will encode this command into a wire message for the given server description. |
| func (d *Distinct) encode(desc description.SelectedServer) (*Read, error) { |
| if err := d.NS.Validate(); err != nil { |
| return nil, err |
| } |
| |
| command := bsonx.Doc{{"distinct", bsonx.String(d.NS.Collection)}, {"key", bsonx.String(d.Field)}} |
| |
| if d.Query != nil { |
| command = append(command, bsonx.Elem{"query", bsonx.Document(d.Query)}) |
| } |
| |
| command = append(command, d.Opts...) |
| |
| return &Read{ |
| Clock: d.Clock, |
| DB: d.NS.DB, |
| ReadPref: d.ReadPref, |
| Command: command, |
| ReadConcern: d.ReadConcern, |
| Session: d.Session, |
| }, nil |
| } |
| |
| // Decode will decode the wire message using the provided server description. Errors during decoding |
| // are deferred until either the Result or Err methods are called. |
| func (d *Distinct) Decode(desc description.SelectedServer, wm wiremessage.WireMessage) *Distinct { |
| rdr, err := (&Read{}).Decode(desc, wm).Result() |
| if err != nil { |
| d.err = err |
| return d |
| } |
| |
| return d.decode(desc, rdr) |
| } |
| |
| func (d *Distinct) decode(desc description.SelectedServer, rdr bson.Raw) *Distinct { |
| d.err = bson.Unmarshal(rdr, &d.result) |
| return d |
| } |
| |
| // Result returns the result of a decoded wire message and server description. |
| func (d *Distinct) Result() (result.Distinct, error) { |
| if d.err != nil { |
| return result.Distinct{}, d.err |
| } |
| return d.result, nil |
| } |
| |
| // Err returns the error set on this command. |
| func (d *Distinct) Err() error { return d.err } |
| |
| // RoundTrip handles the execution of this command using the provided wiremessage.ReadWriter. |
| func (d *Distinct) RoundTrip(ctx context.Context, desc description.SelectedServer, rw wiremessage.ReadWriter) (result.Distinct, error) { |
| cmd, err := d.encode(desc) |
| if err != nil { |
| return result.Distinct{}, err |
| } |
| |
| rdr, err := cmd.RoundTrip(ctx, desc, rw) |
| if err != nil { |
| return result.Distinct{}, err |
| } |
| |
| return d.decode(desc, rdr).Result() |
| } |