myname: Factor out routines to get current function name & package from exc

Usage would be:

	myname.Func(),	and
	myname.Pkg()

exc/error.go

@@ -17,6 +17,8 @@ import (
     "fmt"
     "runtime"
     "strings"
+
+    "lab.nexedi.com/kirr/go123/myname"
 )
 
 // error type which is raised by raise(arg)
@@ -133,43 +135,6 @@ func erraddcontext(e *Error, arg interface{}) *Error {
     return &Error{arg, e}
 }
 
-func _myfuncname(nskip int) string {
-    pcv := [1]uintptr{}
-    runtime.Callers(nskip, pcv[:])
-    f := runtime.FuncForPC(pcv[0])
-    if f == nil {
-        return ""
-    }
-    return f.Name()
-}
-
-// get name of currently running function (caller of myfuncname())
-// name is fully qualified package/name.function(.x)
-func myfuncname() string {
-    return _myfuncname(3)
-}
-
-// get name of currently running function's package
-// package is fully qualified package/name
-func mypkgname() string {
-    myfunc := _myfuncname(3)
-    if myfunc == "" {
-        return ""
-    }
-    // NOTE dots in package name are after last slash are escaped by go as %2e
-    // this way the first '.' after last '/' is delimiter between package and function
-    //
-    // lab.nexedi.com/kirr/git-backup/package%2ename.Function
-    // lab.nexedi.com/kirr/git-backup/pkg2.qqq/name%2ezzz.Function
-    islash := strings.LastIndexByte(myfunc, '/')
-    iafterslash := islash + 1   // NOTE if '/' not found iafterslash = 0
-    idot := strings.IndexByte(myfunc[iafterslash:], '.')
-    if idot == -1 {
-        panic(fmt.Errorf("funcname %q is not fully qualified", myfunc))
-    }
-    return myfunc[:iafterslash+idot]
-}
-
 // TODO(go1.7) goes away in favour of runtime.Frame
 type Frame struct {
     *runtime.Func
@@ -216,7 +181,7 @@ var (
 )
 
 func init() {
-    _errorpkgname = mypkgname()
+    _errorpkgname = myname.Pkg()
     _errorpkgdot  = _errorpkgname + "."
     _errorraise   = _errorpkgname + ".raise"
 }

exc/error_test.go

@@ -14,8 +14,9 @@ package main
 
 import (
     "errors"
-    "strings"
     "testing"
+
+    "lab.nexedi.com/kirr/go123/myname"
 )
 
 func do_raise1() {
@@ -94,16 +95,6 @@ func TestErrContext(t *testing.T) {
     t.Fatal("error not caught")
 }
 
-func TestMyFuncName(t *testing.T) {
-    myfunc := myfuncname()
-    // go test changes full package name (putting filesystem of the tree into ti)
-    // thus we check only for suffix
-    wantsuffix := ".TestMyFuncName"
-    if !strings.HasSuffix(myfunc, wantsuffix) {
-        t.Errorf("myfuncname() -> %v  ; want *%v", myfunc, wantsuffix)
-    }
-}
-
 func do_raise11() {
     do_raise1()
 }
@@ -134,7 +125,7 @@ func TestErrAddCallingContext(t *testing.T) {
 
     for _, tt := range tests {
         func() {
-            myfunc := myfuncname()
+            myfunc := myname.Func()
             defer errcatch(func(e *Error) {
                 e = erraddcallingcontext(myfunc, e)
                 msg := e.Error()

myname/myname.go

+// Copyright (C) 2015-2016  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+
+// Package myname provides easy way to determine current function's name and package
+package myname
+
+import (
+    "fmt"
+    "runtime"
+    "strings"
+)
+
+func _myfuncname(nskip int) string {
+    pcv := [1]uintptr{}
+    runtime.Callers(nskip, pcv[:])
+    f := runtime.FuncForPC(pcv[0])
+    if f == nil {
+        return ""
+    }
+    return f.Name()
+}
+
+// get name of currently running function (caller of Func())
+// name is fully qualified package/name.function(.x)
+func Func() string {
+    return _myfuncname(3)
+}
+
+// get name of currently running function's package
+// package is fully qualified package/name
+func Pkg() string {
+    myfunc := _myfuncname(3)
+    if myfunc == "" {
+        return ""
+    }
+    // NOTE dots in package name are after last slash are escaped by go as %2e
+    // this way the first '.' after last '/' is delimiter between package and function
+    //
+    // lab.nexedi.com/kirr/git-backup/package%2ename.Function
+    // lab.nexedi.com/kirr/git-backup/pkg2.qqq/name%2ezzz.Function
+    islash := strings.LastIndexByte(myfunc, '/')
+    iafterslash := islash + 1   // NOTE if '/' not found iafterslash = 0
+    idot := strings.IndexByte(myfunc[iafterslash:], '.')
+    if idot == -1 {
+        panic(fmt.Errorf("funcname %q is not fully qualified", myfunc))
+    }
+    return myfunc[:iafterslash+idot]
+}

myname/myname_test.go

+// Copyright (C) 2015-2016  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+
+package myname
+
+import (
+    "strings"
+    "testing"
+)
+
+func TestMyFuncName(t *testing.T) {
+    myfunc := Func()
+    // go test changes full package name (putting filesystem of the tree into ti)
+    // thus we check only for suffix
+    wantsuffix := ".TestMyFuncName"
+    if !strings.HasSuffix(myfunc, wantsuffix) {
+        t.Errorf("myname.Func() -> %v  ; want *%v", myfunc, wantsuffix)
+    }
+}