You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
214 lines
4.9 KiB
214 lines
4.9 KiB
package common
|
|
|
|
import (
|
|
"fmt"
|
|
"runtime"
|
|
)
|
|
|
|
//----------------------------------------
|
|
// Convenience method.
|
|
|
|
func ErrorWrap(cause interface{}, format string, args ...interface{}) Error {
|
|
if causeCmnError, ok := cause.(*cmnError); ok {
|
|
msg := fmt.Sprintf(format, args...)
|
|
return causeCmnError.Stacktrace().Trace(1, msg)
|
|
} else if cause == nil {
|
|
return newCmnError(FmtError{format, args}).Stacktrace()
|
|
} else {
|
|
// NOTE: causeCmnError is a typed nil here.
|
|
msg := fmt.Sprintf(format, args...)
|
|
return newCmnError(cause).Stacktrace().Trace(1, msg)
|
|
}
|
|
}
|
|
|
|
//----------------------------------------
|
|
// Error & cmnError
|
|
|
|
/*
|
|
|
|
Usage with arbitrary error data:
|
|
|
|
```go
|
|
// Error construction
|
|
type MyError struct{}
|
|
var err1 error = NewErrorWithData(MyError{}, "my message")
|
|
...
|
|
// Wrapping
|
|
var err2 error = ErrorWrap(err1, "another message")
|
|
if (err1 != err2) { panic("should be the same")
|
|
...
|
|
// Error handling
|
|
switch err2.Data().(type){
|
|
case MyError: ...
|
|
default: ...
|
|
}
|
|
```
|
|
*/
|
|
type Error interface {
|
|
Error() string
|
|
Stacktrace() Error
|
|
Trace(offset int, format string, args ...interface{}) Error
|
|
Data() interface{}
|
|
}
|
|
|
|
// New Error with formatted message.
|
|
// The Error's Data will be a FmtError type.
|
|
func NewError(format string, args ...interface{}) Error {
|
|
err := FmtError{format, args}
|
|
return newCmnError(err)
|
|
}
|
|
|
|
// New Error with specified data.
|
|
func NewErrorWithData(data interface{}) Error {
|
|
return newCmnError(data)
|
|
}
|
|
|
|
type cmnError struct {
|
|
data interface{} // associated data
|
|
msgtraces []msgtraceItem // all messages traced
|
|
stacktrace []uintptr // first stack trace
|
|
}
|
|
|
|
var _ Error = &cmnError{}
|
|
|
|
// NOTE: do not expose.
|
|
func newCmnError(data interface{}) *cmnError {
|
|
return &cmnError{
|
|
data: data,
|
|
msgtraces: nil,
|
|
stacktrace: nil,
|
|
}
|
|
}
|
|
|
|
// Implements error.
|
|
func (err *cmnError) Error() string {
|
|
return fmt.Sprintf("%v", err)
|
|
}
|
|
|
|
// Captures a stacktrace if one was not already captured.
|
|
func (err *cmnError) Stacktrace() Error {
|
|
if err.stacktrace == nil {
|
|
var offset = 3
|
|
var depth = 32
|
|
err.stacktrace = captureStacktrace(offset, depth)
|
|
}
|
|
return err
|
|
}
|
|
|
|
// Add tracing information with msg.
|
|
// Set n=0 unless wrapped with some function, then n > 0.
|
|
func (err *cmnError) Trace(offset int, format string, args ...interface{}) Error {
|
|
msg := fmt.Sprintf(format, args...)
|
|
return err.doTrace(msg, offset)
|
|
}
|
|
|
|
// Return the "data" of this error.
|
|
// Data could be used for error handling/switching,
|
|
// or for holding general error/debug information.
|
|
func (err *cmnError) Data() interface{} {
|
|
return err.data
|
|
}
|
|
|
|
func (err *cmnError) doTrace(msg string, n int) Error {
|
|
pc, _, _, _ := runtime.Caller(n + 2) // +1 for doTrace(). +1 for the caller.
|
|
// Include file & line number & msg.
|
|
// Do not include the whole stack trace.
|
|
err.msgtraces = append(err.msgtraces, msgtraceItem{
|
|
pc: pc,
|
|
msg: msg,
|
|
})
|
|
return err
|
|
}
|
|
|
|
func (err *cmnError) Format(s fmt.State, verb rune) {
|
|
switch verb {
|
|
case 'p':
|
|
s.Write([]byte(fmt.Sprintf("%p", &err)))
|
|
default:
|
|
if s.Flag('#') {
|
|
s.Write([]byte("--= Error =--\n"))
|
|
// Write data.
|
|
s.Write([]byte(fmt.Sprintf("Data: %#v\n", err.data)))
|
|
// Write msg trace items.
|
|
s.Write([]byte(fmt.Sprintf("Msg Traces:\n")))
|
|
for i, msgtrace := range err.msgtraces {
|
|
s.Write([]byte(fmt.Sprintf(" %4d %s\n", i, msgtrace.String())))
|
|
}
|
|
// Write stack trace.
|
|
if err.stacktrace != nil {
|
|
s.Write([]byte(fmt.Sprintf("Stack Trace:\n")))
|
|
for i, pc := range err.stacktrace {
|
|
fnc := runtime.FuncForPC(pc)
|
|
file, line := fnc.FileLine(pc)
|
|
s.Write([]byte(fmt.Sprintf(" %4d %s:%d\n", i, file, line)))
|
|
}
|
|
}
|
|
s.Write([]byte("--= /Error =--\n"))
|
|
} else {
|
|
// Write msg.
|
|
s.Write([]byte(fmt.Sprintf("%v", err.data)))
|
|
}
|
|
}
|
|
}
|
|
|
|
//----------------------------------------
|
|
// stacktrace & msgtraceItem
|
|
|
|
func captureStacktrace(offset int, depth int) []uintptr {
|
|
var pcs = make([]uintptr, depth)
|
|
n := runtime.Callers(offset, pcs)
|
|
return pcs[0:n]
|
|
}
|
|
|
|
type msgtraceItem struct {
|
|
pc uintptr
|
|
msg string
|
|
}
|
|
|
|
func (mti msgtraceItem) String() string {
|
|
fnc := runtime.FuncForPC(mti.pc)
|
|
file, line := fnc.FileLine(mti.pc)
|
|
return fmt.Sprintf("%s:%d - %s",
|
|
file, line,
|
|
mti.msg,
|
|
)
|
|
}
|
|
|
|
//----------------------------------------
|
|
// fmt error
|
|
|
|
/*
|
|
|
|
FmtError is the data type for NewError() (e.g. NewError().Data().(FmtError))
|
|
Theoretically it could be used to switch on the format string.
|
|
|
|
```go
|
|
// Error construction
|
|
var err1 error = NewError("invalid username %v", "BOB")
|
|
var err2 error = NewError("another kind of error")
|
|
...
|
|
// Error handling
|
|
switch err1.Data().(cmn.FmtError).Format() {
|
|
case "invalid username %v": ...
|
|
case "another kind of error": ...
|
|
default: ...
|
|
}
|
|
```
|
|
*/
|
|
type FmtError struct {
|
|
format string
|
|
args []interface{}
|
|
}
|
|
|
|
func (fe FmtError) Error() string {
|
|
return fmt.Sprintf(fe.format, fe.args...)
|
|
}
|
|
|
|
func (fe FmtError) String() string {
|
|
return fmt.Sprintf("FmtError{format:%v,args:%v}",
|
|
fe.format, fe.args)
|
|
}
|
|
|
|
func (fe FmtError) Format() string {
|
|
return fe.format
|
|
}
|