Split stack.Location into a private helper
diff --git a/errors.go b/errors.go
index 8ee3059..c73c66d 100644
--- a/errors.go
+++ b/errors.go
@@ -59,52 +59,7 @@
type stack []uintptr
func (s stack) Location() (string, int) {
- pc := s[0] - 1
- fn := runtime.FuncForPC(pc)
- if fn == nil {
- return "unknown", 0
- }
-
- file, line := fn.FileLine(pc)
-
- // Here we want to get the source file path relative to the compile time
- // GOPATH. As of Go 1.6.x there is no direct way to know the compiled
- // GOPATH at runtime, but we can infer the number of path segments in the
- // GOPATH. We note that fn.Name() returns the function name qualified by
- // the import path, which does not include the GOPATH. Thus we can trim
- // segments from the beginning of the file path until the number of path
- // separators remaining is one more than the number of path separators in
- // the function name. For example, given:
- //
- // GOPATH /home/user
- // file /home/user/src/pkg/sub/file.go
- // fn.Name() pkg/sub.Type.Method
- //
- // We want to produce:
- //
- // pkg/sub/file.go
- //
- // From this we can easily see that fn.Name() has one less path separator
- // than our desired output. We count separators from the end of the file
- // path until it finds two more than in the function name and then move
- // one character forward to preserve the initial path segment without a
- // leading separator.
- const sep = "/"
- goal := strings.Count(fn.Name(), sep) + 2
- i := len(file)
- for n := 0; n < goal; n++ {
- i = strings.LastIndex(file[:i], sep)
- if i == -1 {
- // not enough separators found, set i so that the slice expression
- // below leaves file unmodified
- i = -len(sep)
- break
- }
- }
- // get back to 0 or trim the leading separator
- file = file[i+len(sep):]
-
- return file, line
+ return location(s[0] - 1)
}
// New returns an error that formats as the given text.
@@ -241,3 +196,52 @@
n := runtime.Callers(3, pcs[:])
return pcs[0:n]
}
+
+// location returns the source file and line matching pc.
+func location(pc uintptr) (string, int) {
+ fn := runtime.FuncForPC(pc)
+ if fn == nil {
+ return "unknown", 0
+ }
+
+ file, line := fn.FileLine(pc)
+
+ // Here we want to get the source file path relative to the compile time
+ // GOPATH. As of Go 1.6.x there is no direct way to know the compiled
+ // GOPATH at runtime, but we can infer the number of path segments in the
+ // GOPATH. We note that fn.Name() returns the function name qualified by
+ // the import path, which does not include the GOPATH. Thus we can trim
+ // segments from the beginning of the file path until the number of path
+ // separators remaining is one more than the number of path separators in
+ // the function name. For example, given:
+ //
+ // GOPATH /home/user
+ // file /home/user/src/pkg/sub/file.go
+ // fn.Name() pkg/sub.Type.Method
+ //
+ // We want to produce:
+ //
+ // pkg/sub/file.go
+ //
+ // From this we can easily see that fn.Name() has one less path separator
+ // than our desired output. We count separators from the end of the file
+ // path until it finds two more than in the function name and then move
+ // one character forward to preserve the initial path segment without a
+ // leading separator.
+ const sep = "/"
+ goal := strings.Count(fn.Name(), sep) + 2
+ i := len(file)
+ for n := 0; n < goal; n++ {
+ i = strings.LastIndex(file[:i], sep)
+ if i == -1 {
+ // not enough separators found, set i so that the slice expression
+ // below leaves file unmodified
+ i = -len(sep)
+ break
+ }
+ }
+ // get back to 0 or trim the leading separator
+ file = file[i+len(sep):]
+
+ return file, line
+}
