query.gno

 1package datasource
 2
 3import "gno.land/p/nt/avl/v0"
 4
 5// DefaultQueryRecords defines the default number of records returned by queries.
 6const DefaultQueryRecords = 50
 7
 8type (
 9	// QueryOption configures datasource queries.
10	QueryOption func(*Query)
11
12	// Query contains datasource query options.
13	Query struct {
14		// Offset of the first record to return during iteration.
15		Offset int
16
17		// Count contains the number to records that query should return.
18		Count int
19
20		// Tag contains a tag to use as filter for the records.
21		Tag string
22
23		// Filters contains optional query filters by field value.
24		Filters avl.Tree
25	}
26)
27
28// WithOffset configures query to return records starting from an offset.
29func WithOffset(offset int) QueryOption {
30	return func(q *Query) {
31		q.Offset = offset
32	}
33}
34
35// WithCount configures the number of records that query returns.
36func WithCount(count int) QueryOption {
37	return func(q *Query) {
38		if count < 1 {
39			count = DefaultQueryRecords
40		}
41		q.Count = count
42	}
43}
44
45// ByTag configures query to filter by tag.
46func ByTag(tag string) QueryOption {
47	return func(q *Query) {
48		q.Tag = tag
49	}
50}
51
52// WithFilter assigns a new filter argument to a query.
53// This option can be used multiple times if more than one
54// filter has to be given to the query.
55func WithFilter(field string, value any) QueryOption {
56	return func(q *Query) {
57		q.Filters.Set(field, value)
58	}
59}
60
61// NewQuery creates a new datasource query.
62func NewQuery(options ...QueryOption) Query {
63	// Construct a fresh Query in the caller's realm; copying from a
64	// package-level default would propagate the /p/-readonly taint
65	// and break the apply(&q) options below.
66	q := Query{Count: DefaultQueryRecords}
67	for _, apply := range options {
68		apply(&q)
69	}
70	return q
71}