godog/stacktrace.go
2017-04-28 10:54:24 +03:00

141 строка
2,9 КиБ
Go

package godog
import (
"fmt"
"go/build"
"io"
"path"
"path/filepath"
"runtime"
"strings"
)
// Frame represents a program counter inside a stack frame.
type stackFrame uintptr
// pc returns the program counter for this frame;
// multiple frames may have the same PC value.
func (f stackFrame) pc() uintptr { return uintptr(f) - 1 }
// file returns the full path to the file that contains the
// function for this Frame's pc.
func (f stackFrame) file() string {
fn := runtime.FuncForPC(f.pc())
if fn == nil {
return "unknown"
}
file, _ := fn.FileLine(f.pc())
return file
}
func trimGoPath(file string) string {
for _, p := range filepath.SplitList(build.Default.GOPATH) {
file = strings.Replace(file, filepath.Join(p, "src")+string(filepath.Separator), "", 1)
}
return file
}
// line returns the line number of source code of the
// function for this Frame's pc.
func (f stackFrame) line() int {
fn := runtime.FuncForPC(f.pc())
if fn == nil {
return 0
}
_, line := fn.FileLine(f.pc())
return line
}
// Format formats the frame according to the fmt.Formatter interface.
//
// %s source file
// %d source line
// %n function name
// %v equivalent to %s:%d
//
// Format accepts flags that alter the printing of some verbs, as follows:
//
// %+s path of source file relative to the compile time GOPATH
// %+v equivalent to %+s:%d
func (f stackFrame) Format(s fmt.State, verb rune) {
funcname := func(name string) string {
i := strings.LastIndex(name, "/")
name = name[i+1:]
i = strings.Index(name, ".")
return name[i+1:]
}
switch verb {
case 's':
switch {
case s.Flag('+'):
pc := f.pc()
fn := runtime.FuncForPC(pc)
if fn == nil {
io.WriteString(s, "unknown")
} else {
file, _ := fn.FileLine(pc)
fmt.Fprintf(s, "%s\n\t%s", fn.Name(), trimGoPath(file))
}
default:
io.WriteString(s, path.Base(f.file()))
}
case 'd':
fmt.Fprintf(s, "%d", f.line())
case 'n':
name := runtime.FuncForPC(f.pc()).Name()
io.WriteString(s, funcname(name))
case 'v':
f.Format(s, 's')
io.WriteString(s, ":")
f.Format(s, 'd')
}
}
// stack represents a stack of program counters.
type stack []uintptr
func (s *stack) Format(st fmt.State, verb rune) {
switch verb {
case 'v':
switch {
case st.Flag('+'):
for _, pc := range *s {
f := stackFrame(pc)
fmt.Fprintf(st, "\n%+v", f)
}
}
}
}
func callStack() *stack {
const depth = 32
var pcs [depth]uintptr
n := runtime.Callers(3, pcs[:])
var st stack = pcs[0:n]
return &st
}
// fundamental is an error that has a message and a stack, but no caller.
type traceError struct {
msg string
*stack
}
func (f *traceError) Error() string { return f.msg }
func (f *traceError) Format(s fmt.State, verb rune) {
switch verb {
case 'v':
if s.Flag('+') {
io.WriteString(s, f.msg)
f.stack.Format(s, verb)
return
}
fallthrough
case 's':
io.WriteString(s, f.msg)
case 'q':
fmt.Fprintf(s, "%q", f.msg)
}
}