56 lines
1.5 KiB
Go
56 lines
1.5 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package xerrors
|
|
|
|
import (
|
|
"runtime"
|
|
)
|
|
|
|
// A Frame contains part of a call stack.
|
|
type Frame struct {
|
|
// Make room for three PCs: the one we were asked for, what it called,
|
|
// and possibly a PC for skipPleaseUseCallersFrames. See:
|
|
// https://go.googlesource.com/go/+/032678e0fb/src/runtime/extern.go#169
|
|
frames [3]uintptr
|
|
}
|
|
|
|
// Caller returns a Frame that describes a frame on the caller's stack.
|
|
// The argument skip is the number of frames to skip over.
|
|
// Caller(0) returns the frame for the caller of Caller.
|
|
func Caller(skip int) Frame {
|
|
var s Frame
|
|
runtime.Callers(skip+1, s.frames[:])
|
|
return s
|
|
}
|
|
|
|
// location reports the file, line, and function of a frame.
|
|
//
|
|
// The returned function may be "" even if file and line are not.
|
|
func (f Frame) location() (function, file string, line int) {
|
|
frames := runtime.CallersFrames(f.frames[:])
|
|
if _, ok := frames.Next(); !ok {
|
|
return "", "", 0
|
|
}
|
|
fr, ok := frames.Next()
|
|
if !ok {
|
|
return "", "", 0
|
|
}
|
|
return fr.Function, fr.File, fr.Line
|
|
}
|
|
|
|
// Format prints the stack as error detail.
|
|
// It should be called from an error's Format implementation
|
|
// after printing any other error detail.
|
|
func (f Frame) Format(p Printer) {
|
|
if p.Detail() {
|
|
function, file, line := f.location()
|
|
if function != "" {
|
|
p.Printf("%s\n ", function)
|
|
}
|
|
if file != "" {
|
|
p.Printf("%s:%d\n", file, line)
|
|
}
|
|
}
|
|
}
|