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package errors
import (
"errors"
"reflect"
"codeberg.org/gruf/go-bitutil"
)
// Is reports whether any error in err's chain matches any of targets
// (up to a max of 64 targets).
//
// The chain consists of err itself followed by the sequence of errors obtained by
// repeatedly calling Unwrap.
//
// An error is considered to match a target if it is equal to that target or if
// it implements a method Is(error) bool such that Is(target) returns true.
func Is(err error, targets ...error) bool {
var flags bitutil.Flags64
if len(targets) > 64 {
panic("too many targets")
}
// Determine if each of targets are comparable
for i := 0; i < len(targets); {
// Drop nil errors
if targets[i] == nil {
targets = append(targets[:i], targets[i+1:]...)
continue
}
// Check if this error is directly comparable
if reflect.TypeOf(targets[i]).Comparable() {
flags = flags.Set(uint8(i))
}
i++
}
for err != nil {
var errorIs func(error) bool
// Check if this layer supports .Is interface
is, ok := err.(interface{ Is(error) bool })
if ok {
errorIs = is.Is
} else {
errorIs = neveris
}
for i := 0; i < len(targets); i++ {
// Try directly compare errors
if flags.Get(uint8(i)) &&
err == targets[i] {
return true
}
// Try use .Is() interface
if errorIs(targets[i]) {
return true
}
}
// Unwrap to next layer
err = errors.Unwrap(err)
}
return false
}
// As finds the first error in err's chain that matches target, and if one is found, sets
// target to that error value and returns true. Otherwise, it returns false.
//
// The chain consists of err itself followed by the sequence of errors obtained by
// repeatedly calling Unwrap.
//
// An error matches target if the error's concrete value is assignable to the value
// pointed to by target, or if the error has a method As(interface{}) bool such that
// As(target) returns true. In the latter case, the As method is responsible for
// setting target.
//
// An error type might provide an As method so it can be treated as if it were a
// different error type.
//
// As panics if target is not a non-nil pointer to either a type that implements
// error, or to any interface type.
func As(err error, target interface{}) bool {
return errors.As(err, target)
}
// Unwrap returns the result of calling the Unwrap method on err, if err's
// type contains an Unwrap method returning error. Otherwise, Unwrap returns nil.
func Unwrap(err error) error {
return errors.Unwrap(err)
}
// neveris fits the .Is(error) bool interface function always returning false.
func neveris(error) bool { return false }
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