| package errors |
| |
| import ( |
| "fmt" |
| "io" |
| "path" |
| "runtime" |
| "strings" |
| ) |
| |
| // Frame represents a program counter inside a stack frame. |
| type Frame runtime.Frame |
| |
| // file returns the full path to the file that contains the |
| // function for this Frame's pc. |
| func (f Frame) file() string { |
| file := runtime.Frame(f).File |
| if file == "" { |
| return "unknown" |
| } |
| return file |
| } |
| |
| // line returns the line number of source code of the |
| // function for this Frame's pc. |
| func (f Frame) line() int { |
| return runtime.Frame(f).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 function name and path of source file relative to the compile time |
| // GOPATH separated by \n\t (<funcname>\n\t<path>) |
| // %+v equivalent to %+s:%d |
| func (f Frame) Format(s fmt.State, verb rune) { |
| switch verb { |
| case 's': |
| switch { |
| case s.Flag('+'): |
| fn := runtime.Frame(f).Func |
| if fn == nil { |
| io.WriteString(s, "unknown") |
| } else { |
| file := runtime.Frame(f).File |
| fmt.Fprintf(s, "%s\n\t%s", fn.Name(), file) |
| } |
| default: |
| io.WriteString(s, path.Base(f.file())) |
| } |
| case 'd': |
| fmt.Fprintf(s, "%d", f.line()) |
| case 'n': |
| name := runtime.Frame(f).Function |
| io.WriteString(s, funcname(name)) |
| case 'v': |
| f.Format(s, 's') |
| io.WriteString(s, ":") |
| f.Format(s, 'd') |
| } |
| } |
| |
| // StackTrace is stack of Frames from innermost (newest) to outermost (oldest). |
| type StackTrace []Frame |
| |
| // Format formats the stack of Frames according to the fmt.Formatter interface. |
| // |
| // %s lists source files for each Frame in the stack |
| // %v lists the source file and line number for each Frame in the stack |
| // |
| // Format accepts flags that alter the printing of some verbs, as follows: |
| // |
| // %+v Prints filename, function, and line number for each Frame in the stack. |
| func (st StackTrace) Format(s fmt.State, verb rune) { |
| switch verb { |
| case 'v': |
| switch { |
| case s.Flag('+'): |
| for _, f := range st { |
| fmt.Fprintf(s, "\n%+v", f) |
| } |
| case s.Flag('#'): |
| fmt.Fprintf(s, "%#v", []Frame(st)) |
| default: |
| fmt.Fprintf(s, "%v", []Frame(st)) |
| } |
| case 's': |
| fmt.Fprintf(s, "%s", []Frame(st)) |
| } |
| } |
| |
| // 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('+'): |
| frames := runtime.CallersFrames(*s) |
| for { |
| frame, more := frames.Next() |
| fmt.Fprintf(st, "\n%+v", Frame(frame)) |
| if !more { |
| break |
| } |
| } |
| } |
| } |
| } |
| |
| func (s *stack) StackTrace() StackTrace { |
| var st []Frame |
| frames := runtime.CallersFrames(*s) |
| for { |
| frame, more := frames.Next() |
| st = append(st, Frame(frame)) |
| if !more { |
| break |
| } |
| } |
| return st |
| } |
| |
| func callers() *stack { |
| const depth = 32 |
| var pcs [depth]uintptr |
| n := runtime.Callers(3, pcs[:]) |
| var st stack = pcs[0:n] |
| return &st |
| } |
| |
| // funcname removes the path prefix component of a function's name reported by func.Name(). |
| func funcname(name string) string { |
| i := strings.LastIndex(name, "/") |
| name = name[i+1:] |
| i = strings.Index(name, ".") |
| return name[i+1:] |
| } |