ResourceServer: Resource store sql backend (#90170)

pkg/storage/unified/sql/sqltemplate/args.go

@@ -0,0 +1,85 @@
+package sqltemplate
+
+import (
+	"errors"
+	"reflect"
+	"strings"
+)
+
+// Args errors.
+var (
+	ErrInvalidArgList = errors.New("invalid arglist")
+)
+
+// Args keeps the data that needs to be passed to the engine for execution in
+// the right order. Add it to your data types passed to SQLTemplate, either by
+// embedding or with a named struct field if its Arg method would clash with
+// another struct field.
+type Args struct {
+	d      interface{ ArgPlaceholder(argNum int) string }
+	values []any
+}
+
+func NewArgs(d Dialect) *Args {
+	return &Args{
+		d: d,
+	}
+}
+
+// Arg can be called from within templates to pass arguments to the SQL driver
+// to use in the execution of the query.
+func (a *Args) Arg(x any) string {
+	a.values = append(a.values, x)
+
+	return a.d.ArgPlaceholder(len(a.values))
+}
+
+// ArgList returns a comma separated list of `?` placeholders for each element
+// in the provided slice argument, calling Arg for each of them.
+// Example struct:
+//
+//	type sqlMyRequest struct {
+//		*sqltemplate.SQLTemplate
+//		IDs []int64
+//	}
+//
+// Example usage in a SQL template:
+//
+//	DELETE FROM {{ .Ident "mytab" }}
+//		WHERE id IN ( {{ argList . .IDs }} )
+//	;
+func (a *Args) ArgList(slice reflect.Value) (string, error) {
+	if !slice.IsValid() || slice.Kind() != reflect.Slice {
+		return "", ErrInvalidArgList
+	}
+	sliceLen := slice.Len()
+	if sliceLen == 0 {
+		return "", nil
+	}
+
+	var b strings.Builder
+	b.Grow(3*sliceLen - 2) // the list will be ?, ?, ?
+	for i, l := 0, slice.Len(); i < l; i++ {
+		if i > 0 {
+			b.WriteString(", ")
+		}
+		b.WriteString(a.Arg(slice.Index(i).Interface()))
+	}
+
+	return b.String(), nil
+}
+
+func (a *Args) Reset() {
+	a.values = nil
+}
+
+func (a *Args) GetArgs() []any {
+	return a.values
+}
+
+type ArgsIface interface {
+	Arg(x any) string
+	ArgList(slice reflect.Value) (string, error)
+	GetArgs() []any
+	Reset()
+}