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ceph-csi/vendor/github.com/ansel1/merry/v2/errors.go

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package merry
import (
"errors"
"fmt"
"runtime"
)
// New creates a new error, with a stack attached. The equivalent of golang's errors.New()
func New(msg string, wrappers ...Wrapper) error {
return WrapSkipping(errors.New(msg), 1, wrappers...)
}
// Errorf creates a new error with a formatted message and a stack. The equivalent of golang's fmt.Errorf().
// args may contain either arguments to format, or Wrapper options, which will be applied to the error.
func Errorf(format string, args ...interface{}) error {
fmtArgs, wrappers := splitWrappers(args)
return WrapSkipping(fmt.Errorf(format, fmtArgs...), 1, wrappers...)
}
// Sentinel creates an error without running hooks or capturing a stack. It is intended
// to create sentinel errors, which will be wrapped with a stack later from where the
// error is returned. At that time, a stack will be captured and hooks will be run.
//
// var ErrNotFound = merry.Sentinel("not found", merry.WithHTTPCode(404))
//
// func FindUser(name string) (*User, error) {
// // some db code which fails to find a user
// return nil, merry.Wrap(ErrNotFound)
// }
//
// func main() {
// _, err := FindUser("bob")
// fmt.Println(errors.Is(err, ErrNotFound) // "true"
// fmt.Println(merry.Details(err)) // stacktrace will start at the return statement
// // in FindUser()
// }
func Sentinel(msg string, wrappers ...Wrapper) error {
return ApplySkipping(errors.New(msg), 1, wrappers...)
}
// Sentinelf is like Sentinel, but takes a formatted message. args can be a mix of
// format arguments and Wrappers.
func Sentinelf(format string, args ...interface{}) error {
fmtArgs, wrappers := splitWrappers(args)
return ApplySkipping(fmt.Errorf(format, fmtArgs...), 1, wrappers...)
}
func splitWrappers(args []interface{}) ([]interface{}, []Wrapper) {
var wrappers []Wrapper
// pull out the args which are wrappers
n := 0
for _, arg := range args {
if w, ok := arg.(Wrapper); ok {
wrappers = append(wrappers, w)
} else {
args[n] = arg
n++
}
}
args = args[:n]
return args, wrappers
}
// Wrap adds context to errors by applying Wrappers. See WithXXX() functions for Wrappers supplied
// by this package.
//
// If StackCaptureEnabled is true, a stack starting at the caller will be automatically captured
// and attached to the error. This behavior can be overridden with wrappers which either capture
// their own stacks, or suppress auto capture.
//
// If err is nil, returns nil.
func Wrap(err error, wrappers ...Wrapper) error {
return WrapSkipping(err, 1, wrappers...)
}
// WrapSkipping is like Wrap, but the captured stacks will start `skip` frames
// further up the call stack. If skip is 0, it behaves the same as Wrap.
func WrapSkipping(err error, skip int, wrappers ...Wrapper) error {
if err == nil {
return nil
}
if len(onceHooks) > 0 {
if _, ok := Lookup(err, errKeyHooked); !ok {
err = ApplySkipping(err, skip+1, onceHooks...)
err = ApplySkipping(err, skip+1, WithValue(errKeyHooked, err))
}
}
err = ApplySkipping(err, skip+1, hooks...)
err = ApplySkipping(err, skip+1, wrappers...)
return captureStack(err, skip+1, false)
}
// Apply is like Wrap, but does not execute hooks or do automatic stack capture. It just
// applies the wrappers to the error.
func Apply(err error, wrappers ...Wrapper) error {
return ApplySkipping(err, 1, wrappers...)
}
// ApplySkipping is like WrapSkipping, but does not execute hooks or do automatic stack capture. It just
// applies the wrappers to the error. It is useful in Wrapper implementations which
// // want to apply other Wrappers without starting an infinite recursion.
func ApplySkipping(err error, skip int, wrappers ...Wrapper) error {
if err == nil {
return nil
}
for _, w := range wrappers {
err = w.Wrap(err, skip+1)
}
return err
}
// Prepend is a convenience function for the PrependMessage wrapper. It eases migration
// from merry v1. It accepts a varargs of additional Wrappers.
func Prepend(err error, msg string, wrappers ...Wrapper) error {
return WrapSkipping(err, 1, append(wrappers, PrependMessage(msg))...)
}
// Prependf is a convenience function for the PrependMessagef wrapper. It eases migration
// from merry v1. The args can be format arguments mixed with Wrappers.
func Prependf(err error, format string, args ...interface{}) error {
fmtArgs, wrappers := splitWrappers(args)
return WrapSkipping(err, 1, append(wrappers, PrependMessagef(format, fmtArgs...))...)
}
// Append is a convenience function for the AppendMessage wrapper. It eases migration
// from merry v1. It accepts a varargs of additional Wrappers.
func Append(err error, msg string, wrappers ...Wrapper) error {
return WrapSkipping(err, 1, append(wrappers, AppendMessage(msg))...)
}
// Appendf is a convenience function for the AppendMessagef wrapper. It eases migration
// from merry v1. The args can be format arguments mixed with Wrappers.
func Appendf(err error, format string, args ...interface{}) error {
fmtArgs, wrappers := splitWrappers(args)
return WrapSkipping(err, 1, append(wrappers, AppendMessagef(format, fmtArgs...))...)
}
// Value returns the value for key, or nil if not set.
// If e is nil, returns nil. Will not search causes.
func Value(err error, key interface{}) interface{} {
v, _ := Lookup(err, key)
return v
}
// Lookup returns the value for the key, and a boolean indicating
// whether the value was set. Will not search causes.
//
// if err is nil, returns nil and false.
func Lookup(err error, key interface{}) (interface{}, bool) {
var merr interface {
error
isMerryError()
}
// I've tried implementing this logic a few different ways. It's tricky:
//
// - Lookup should only search the current error, but not causes. errWithCause's
// Unwrap() will eventually unwrap to the cause, so we don't want to just
// search the entire stream of errors returned by Unwrap.
// - We need to handle cases where error implementations created outside
// this package are in the middle of the chain. We need to use Unwrap
// in these cases to traverse those errors and dig down to the next
// merry error.
// - Some error packages, including our own, do funky stuff with Unwrap(),
// returning shim types to control the unwrapping order, rather than
// the actual, raw wrapped error. Typically, these shims implement
// Is/As to delegate to the raw error they encapsulate, but implement
// Unwrap by encapsulating the raw error in another shim. So if we're looking
// for a raw error type, we can't just use Unwrap() and do type assertions
// against the result. We have to use errors.As(), to allow the shims to delegate
// the type assertion to the raw error correctly.
//
// Based on all these constraints, we use errors.As() with an internal interface
// that can only be implemented by our internal error types. When one is found,
// we handle each of our internal types as a special case. For errWithCause, we
// traverse to the wrapped error, ignoring the cause and the funky Unwrap logic.
// We could have just used errors.As(err, *errWithValue), but that would have
// traversed into the causes.
for {
switch t := err.(type) {
case *errWithValue:
if t.key == key {
return t.value, true
}
err = t.err
case *errWithCause:
err = t.err
default:
if errors.As(err, &merr) {
err = merr
} else {
return nil, false
}
}
}
}
// Values returns a map of all values attached to the error
// If a key has been attached multiple times, the map will
// contain the last value mapped
// If e is nil, returns nil.
func Values(err error) map[interface{}]interface{} {
var values map[interface{}]interface{}
for err != nil {
if e, ok := err.(*errWithValue); ok {
if _, ok := values[e.key]; !ok {
if values == nil {
values = map[interface{}]interface{}{}
}
values[e.key] = e.value
}
}
err = errors.Unwrap(err)
}
return values
}
// Stack returns the stack attached to an error, or nil if one is not attached
// If e is nil, returns nil.
func Stack(err error) []uintptr {
stack, _ := Value(err, errKeyStack).([]uintptr)
return stack
}
// HTTPCode converts an error to an http status code. All errors
// map to 500, unless the error has an http code attached.
// If e is nil, returns 200.
func HTTPCode(err error) int {
if err == nil {
return 200
}
code, _ := Value(err, errKeyHTTPCode).(int)
if code == 0 {
return 500
}
return code
}
// UserMessage returns the end-user safe message. Returns empty if not set.
// If e is nil, returns "".
func UserMessage(err error) string {
msg, _ := Value(err, errKeyUserMessage).(string)
return msg
}
// Cause returns the cause of the argument. If e is nil, or has no cause,
// nil is returned.
func Cause(err error) error {
var causer *errWithCause
if errors.As(err, &causer) {
return causer.cause
}
return nil
}
// RegisteredDetails extracts details registered with RegisterDetailFunc from an error, and
// returns them as a map. Values may be nil.
//
// If err is nil or there are no registered details, nil is returned.
func RegisteredDetails(err error) map[string]interface{} {
detailsLock.Lock()
defer detailsLock.Unlock()
if len(detailFields) == 0 || err == nil {
return nil
}
dets := map[string]interface{}{}
for label, f := range detailFields {
dets[label] = f(err)
}
return dets
}
// captureStack: return an error with a stack attached. Stack will skip
// specified frames. skip = 0 will start at caller.
// If the err already has a stack, to auto-stack-capture is disabled globally,
// this is a no-op. Use force to override and force a stack capture
// in all cases.
func captureStack(err error, skip int, force bool) error {
if err == nil {
return nil
}
var c interface {
Callers() []uintptr
}
switch {
case force:
// always capture
case HasStack(err):
return err
case errors.As(err, &c):
// if the go-errors already captured a stack
// reuse it
if stack := c.Callers(); len(stack) > 0 {
return Set(err, errKeyStack, stack)
}
case !captureStacks:
return err
}
s := make([]uintptr, MaxStackDepth())
length := runtime.Callers(2+skip, s[:])
return Set(err, errKeyStack, s[:length])
}
// HasStack returns true if a stack is already attached to the err.
// If err == nil, returns false.
//
// If a stack capture was suppressed with NoCaptureStack(), this will
// still return true, indicating that stack capture processing has already
// occurred on this error.
func HasStack(err error) bool {
_, ok := Lookup(err, errKeyStack)
return ok
}