goparsify/debug/frames.go
2017-08-10 21:08:18 +10:00

67 lines
1.3 KiB
Go

package debug
import (
"bufio"
"fmt"
"os"
"path/filepath"
"regexp"
"runtime"
"strings"
)
var varRegex = regexp.MustCompile(`(?:var)?\s*(\w*)\s*:?=`)
func getPackageName(f runtime.Frame) string {
parts := strings.Split(f.Func.Name(), ".")
pl := len(parts)
if parts[pl-2][0] == '(' {
return strings.Join(parts[0:pl-2], ".")
} else {
return strings.Join(parts[0:pl-1], ".")
}
}
func getVarName(filename string, lineNo int) string {
f, err := os.Open(filename)
if err != nil {
return ""
}
scanner := bufio.NewScanner(f)
for i := 0; i < lineNo; i++ {
scanner.Scan()
}
line := scanner.Text()
if matches := varRegex.FindStringSubmatch(line); matches != nil {
return matches[1]
}
return ""
}
// GetDefinition returns the name of the variable and location this parser was defined by walking up the stack
func GetDefinition() (varName string, location string) {
pc := make([]uintptr, 64)
n := runtime.Callers(3, pc)
frames := runtime.CallersFrames(pc[:n])
var frame runtime.Frame
more := true
for more {
frame, more = frames.Next()
pkg := getPackageName(frame)
if pkg == "github.com/vektah/goparsify" || pkg == "github.com/vektah/goparsify/debug" {
continue
}
varName := getVarName(frame.File, frame.Line)
if varName != "" {
return varName, fmt.Sprintf("%s:%d", filepath.Base(frame.File), frame.Line)
}
}
return "", ""
}