mirror of https://github.com/jackc/pgx.git
47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
package anynil
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import (
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"database/sql/driver"
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"reflect"
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)
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// valuerReflectType is a reflect.Type for driver.Valuer. It has confusing syntax because reflect.TypeOf returns nil
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// when it's argument is a nil interface value. So we use a pointer to the interface and call Elem to get the actual
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// type. Yuck.
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//
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// This can be simplified in Go 1.22 with reflect.TypeFor.
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//
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// var valuerReflectType = reflect.TypeFor[driver.Valuer]()
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var valuerReflectType = reflect.TypeOf((*driver.Valuer)(nil)).Elem()
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// Is returns true if value is any type of nil unless it implements driver.Valuer. *T is not considered to implement
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// driver.Valuer if it is only implemented by T.
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func Is(value any) bool {
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if value == nil {
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return true
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}
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refVal := reflect.ValueOf(value)
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kind := refVal.Kind()
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switch kind {
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case reflect.Chan, reflect.Func, reflect.Map, reflect.Ptr, reflect.UnsafePointer, reflect.Interface, reflect.Slice:
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if !refVal.IsNil() {
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return false
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}
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if _, ok := value.(driver.Valuer); ok {
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if kind == reflect.Ptr {
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// The type assertion will succeed if driver.Valuer is implemented on T or *T. Check if it is implemented on T
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// to see if it is not implemented on *T.
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return refVal.Type().Elem().Implements(valuerReflectType)
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} else {
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return false
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}
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}
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return true
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default:
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return false
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}
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}
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