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
7package command
8
9import (
10	"context"
11
12	"go.mongodb.org/mongo-driver/bson"
13	"go.mongodb.org/mongo-driver/mongo/readpref"
14	"go.mongodb.org/mongo-driver/x/bsonx"
15	"go.mongodb.org/mongo-driver/x/mongo/driver/session"
16	"go.mongodb.org/mongo-driver/x/network/description"
17	"go.mongodb.org/mongo-driver/x/network/wiremessage"
18)
19
20// ListCollections represents the listCollections command.
21//
22// The listCollections command lists the collections in a database.
23type ListCollections struct {
24	Clock      *session.ClusterClock
25	DB         string
26	Filter     bsonx.Doc
27	CursorOpts []bsonx.Elem
28	Opts       []bsonx.Elem
29	ReadPref   *readpref.ReadPref
30	Session    *session.Client
31
32	result bson.Raw
33	err    error
34}
35
36// Encode will encode this command into a wire message for the given server description.
37func (lc *ListCollections) Encode(desc description.SelectedServer) (wiremessage.WireMessage, error) {
38	encoded, err := lc.encode(desc)
39	if err != nil {
40		return nil, err
41	}
42	return encoded.Encode(desc)
43}
44
45func (lc *ListCollections) encode(desc description.SelectedServer) (*Read, error) {
46	cmd := bsonx.Doc{{"listCollections", bsonx.Int32(1)}}
47
48	if lc.Filter != nil {
49		cmd = append(cmd, bsonx.Elem{"filter", bsonx.Document(lc.Filter)})
50	}
51	cmd = append(cmd, lc.Opts...)
52
53	return &Read{
54		Clock:    lc.Clock,
55		DB:       lc.DB,
56		Command:  cmd,
57		ReadPref: lc.ReadPref,
58		Session:  lc.Session,
59	}, nil
60}
61
62// Decode will decode the wire message using the provided server description. Errors during decolcng
63// are deferred until either the Result or Err methods are called.
64func (lc *ListCollections) Decode(desc description.SelectedServer, wm wiremessage.WireMessage) *ListCollections {
65	rdr, err := (&Read{}).Decode(desc, wm).Result()
66	if err != nil {
67		lc.err = err
68		return lc
69	}
70	return lc.decode(desc, rdr)
71}
72
73func (lc *ListCollections) decode(desc description.SelectedServer, rdr bson.Raw) *ListCollections {
74	lc.result = rdr
75	return lc
76}
77
78// Result returns the result of a decoded wire message and server description.
79func (lc *ListCollections) Result() (bson.Raw, error) {
80	if lc.err != nil {
81		return nil, lc.err
82	}
83	return lc.result, nil
84}
85
86// Err returns the error set on this command.
87func (lc *ListCollections) Err() error { return lc.err }
88
89// RoundTrip handles the execution of this command using the provided wiremessage.ReadWriter.
90func (lc *ListCollections) RoundTrip(ctx context.Context, desc description.SelectedServer, rw wiremessage.ReadWriter) (bson.Raw, error) {
91	cmd, err := lc.encode(desc)
92	if err != nil {
93		return nil, err
94	}
95
96	rdr, err := cmd.RoundTrip(ctx, desc, rw)
97	if err != nil {
98		return nil, err
99	}
100
101	return lc.decode(desc, rdr).Result()
102}
103