exec.go

Documentation: k8s.io/client-go/third_party/forked/golang/template

     1  //This package is copied from Go library text/template.
     2  //The original private functions indirect and printableValue
     3  //are exported as public functions.
     4  package template
     5  
     6  import (
     7  	"fmt"
     8  	"reflect"
     9  )
    10  
    11  var (
    12  	errorType       = reflect.TypeOf((*error)(nil)).Elem()
    13  	fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
    14  )
    15  
    16  // Indirect returns the item at the end of indirection, and a bool to indicate if it's nil.
    17  // We indirect through pointers and empty interfaces (only) because
    18  // non-empty interfaces have methods we might need.
    19  func Indirect(v reflect.Value) (rv reflect.Value, isNil bool) {
    20  	for ; v.Kind() == reflect.Pointer || v.Kind() == reflect.Interface; v = v.Elem() {
    21  		if v.IsNil() {
    22  			return v, true
    23  		}
    24  		if v.Kind() == reflect.Interface && v.NumMethod() > 0 {
    25  			break
    26  		}
    27  	}
    28  	return v, false
    29  }
    30  
    31  // PrintableValue returns the, possibly indirected, interface value inside v that
    32  // is best for a call to formatted printer.
    33  func PrintableValue(v reflect.Value) (interface{}, bool) {
    34  	if v.Kind() == reflect.Pointer {
    35  		v, _ = Indirect(v) // fmt.Fprint handles nil.
    36  	}
    37  	if !v.IsValid() {
    38  		return "<no value>", true
    39  	}
    40  
    41  	if !v.Type().Implements(errorType) && !v.Type().Implements(fmtStringerType) {
    42  		if v.CanAddr() && (reflect.PointerTo(v.Type()).Implements(errorType) || reflect.PointerTo(v.Type()).Implements(fmtStringerType)) {
    43  			v = v.Addr()
    44  		} else {
    45  			switch v.Kind() {
    46  			case reflect.Chan, reflect.Func:
    47  				return nil, false
    48  			}
    49  		}
    50  	}
    51  	return v.Interface(), true
    52  }
    53
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