reimplement Lshortfile for log wrapper

Fixes all debug messages having "logger:<line>:" instead of the actual
caller.

logger.go

@@ -3,6 +3,8 @@ package main
 import (
 	"io"
 	"log"
+	"runtime"
+	"strconv"
 
 	c "github.com/fatih/color"
 )
@@ -16,24 +18,84 @@ type Logger interface {
 }
 
 type logger struct {
-	logger  *log.Logger
-	printer *c.Color
+	logger    *log.Logger
+	shortfile bool
+	printer   *c.Color
+}
+
+func Lshortfile() string {
+	_, file, line, ok := runtime.Caller(2)
+	lineString := strconv.Itoa(line)
+	if !ok {
+		return ""
+	}
+	if file == "" {
+		return lineString
+	}
+	for i := len(file) - 1; i > 0; i-- {
+		if file[i] == '/' || file[i] == '\\' {
+			file = file[i+1:]
+			break
+		}
+	}
+	return file + ":" + lineString + ":"
 }
 
 func NewLogger(out io.Writer, prefix string, flag int, color c.Attribute) (l logger) {
+	// Use reimplemented Lshortfile since wrapping the log functions messes them up
+	if flag&log.Lshortfile != 0 {
+		flag -= log.Lshortfile
+		l.shortfile = true
+	}
+
 	l.logger = log.New(out, prefix, flag)
 	l.printer = c.New(color)
 	return l
 }
 
 func (l logger) Printf(format string, v ...interface{}) {
-	l.logger.Print(l.printer.Sprintf(format, v...))
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprintf(format, v...)
+	l.logger.Print(out)
 }
-func (l logger) Print(v ...interface{})   { l.logger.Print(l.printer.Sprint(v...)) }
-func (l logger) Println(v ...interface{}) { l.logger.Print(l.printer.Sprintln(v...)) }
-func (l logger) Fatal(v ...interface{})   { l.logger.Fatal(l.printer.Sprint(v...)) }
+
+func (l logger) Print(v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprint(v...)
+	l.logger.Print(out)
+}
+
+func (l logger) Println(v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprintln(v...)
+	l.logger.Print(out)
+}
+
+func (l logger) Fatal(v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprint(v...)
+	l.logger.Fatal(out)
+}
+
 func (l logger) Fatalf(format string, v ...interface{}) {
-	l.logger.Fatal(l.printer.Sprintf(format, v...))
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprintf(format, v...)
+	l.logger.Fatal(out)
 }
 
 type emptyLogger bool