parent
a0c5d14b8d
commit
aa53a56f95
@ -0,0 +1,324 @@ |
||||
// +build go1.7
|
||||
|
||||
// Package stack implements utilities to capture, manipulate, and format call
|
||||
// stacks. It provides a simpler API than package runtime.
|
||||
//
|
||||
// The implementation takes care of the minutia and special cases of
|
||||
// interpreting the program counter (pc) values returned by runtime.Callers.
|
||||
//
|
||||
// Package stack's types implement fmt.Formatter, which provides a simple and
|
||||
// flexible way to declaratively configure formatting when used with logging
|
||||
// or error tracking packages.
|
||||
package stack |
||||
|
||||
import ( |
||||
"bytes" |
||||
"errors" |
||||
"fmt" |
||||
"io" |
||||
"runtime" |
||||
"strconv" |
||||
"strings" |
||||
) |
||||
|
||||
// Call records a single function invocation from a goroutine stack.
|
||||
type Call struct { |
||||
frame runtime.Frame |
||||
} |
||||
|
||||
// Caller returns a Call from the stack of the current goroutine. The argument
|
||||
// skip is the number of stack frames to ascend, with 0 identifying the
|
||||
// calling function.
|
||||
func Caller(skip int) Call { |
||||
// As of Go 1.9 we need room for up to three PC entries.
|
||||
//
|
||||
// 0. An entry for the stack frame prior to the target to check for
|
||||
// special handling needed if that prior entry is runtime.sigpanic.
|
||||
// 1. A possible second entry to hold metadata about skipped inlined
|
||||
// functions. If inline functions were not skipped the target frame
|
||||
// PC will be here.
|
||||
// 2. A third entry for the target frame PC when the second entry
|
||||
// is used for skipped inline functions.
|
||||
var pcs [3]uintptr |
||||
n := runtime.Callers(skip+1, pcs[:]) |
||||
frames := runtime.CallersFrames(pcs[:n]) |
||||
frame, _ := frames.Next() |
||||
frame, _ = frames.Next() |
||||
|
||||
return Call{ |
||||
frame: frame, |
||||
} |
||||
} |
||||
|
||||
// String implements fmt.Stinger. It is equivalent to fmt.Sprintf("%v", c).
|
||||
func (c Call) String() string { |
||||
return fmt.Sprint(c) |
||||
} |
||||
|
||||
// MarshalText implements encoding.TextMarshaler. It formats the Call the same
|
||||
// as fmt.Sprintf("%v", c).
|
||||
func (c Call) MarshalText() ([]byte, error) { |
||||
if c.frame == (runtime.Frame{}) { |
||||
return nil, ErrNoFunc |
||||
} |
||||
|
||||
buf := bytes.Buffer{} |
||||
fmt.Fprint(&buf, c) |
||||
return buf.Bytes(), nil |
||||
} |
||||
|
||||
// ErrNoFunc means that the Call has a nil *runtime.Func. The most likely
|
||||
// cause is a Call with the zero value.
|
||||
var ErrNoFunc = errors.New("no call stack information") |
||||
|
||||
// Format implements fmt.Formatter with support for the following verbs.
|
||||
//
|
||||
// %s source file
|
||||
// %d line number
|
||||
// %n function name
|
||||
// %k last segment of the package path
|
||||
// %v equivalent to %s:%d
|
||||
//
|
||||
// It accepts the '+' and '#' flags for most of the verbs as follows.
|
||||
//
|
||||
// %+s path of source file relative to the compile time GOPATH
|
||||
// %#s full path of source file
|
||||
// %+n import path qualified function name
|
||||
// %+k full package path
|
||||
// %+v equivalent to %+s:%d
|
||||
// %#v equivalent to %#s:%d
|
||||
func (c Call) Format(s fmt.State, verb rune) { |
||||
if c.frame == (runtime.Frame{}) { |
||||
fmt.Fprintf(s, "%%!%c(NOFUNC)", verb) |
||||
return |
||||
} |
||||
|
||||
switch verb { |
||||
case 's', 'v': |
||||
file := c.frame.File |
||||
switch { |
||||
case s.Flag('#'): |
||||
// done
|
||||
case s.Flag('+'): |
||||
file = file[pkgIndex(file, c.frame.Function):] |
||||
default: |
||||
const sep = "/" |
||||
if i := strings.LastIndex(file, sep); i != -1 { |
||||
file = file[i+len(sep):] |
||||
} |
||||
} |
||||
io.WriteString(s, file) |
||||
if verb == 'v' { |
||||
buf := [7]byte{':'} |
||||
s.Write(strconv.AppendInt(buf[:1], int64(c.frame.Line), 10)) |
||||
} |
||||
|
||||
case 'd': |
||||
buf := [6]byte{} |
||||
s.Write(strconv.AppendInt(buf[:0], int64(c.frame.Line), 10)) |
||||
|
||||
case 'k': |
||||
name := c.frame.Function |
||||
const pathSep = "/" |
||||
start, end := 0, len(name) |
||||
if i := strings.LastIndex(name, pathSep); i != -1 { |
||||
start = i + len(pathSep) |
||||
} |
||||
const pkgSep = "." |
||||
if i := strings.Index(name[start:], pkgSep); i != -1 { |
||||
end = start + i |
||||
} |
||||
if s.Flag('+') { |
||||
start = 0 |
||||
} |
||||
io.WriteString(s, name[start:end]) |
||||
|
||||
case 'n': |
||||
name := c.frame.Function |
||||
if !s.Flag('+') { |
||||
const pathSep = "/" |
||||
if i := strings.LastIndex(name, pathSep); i != -1 { |
||||
name = name[i+len(pathSep):] |
||||
} |
||||
const pkgSep = "." |
||||
if i := strings.Index(name, pkgSep); i != -1 { |
||||
name = name[i+len(pkgSep):] |
||||
} |
||||
} |
||||
io.WriteString(s, name) |
||||
} |
||||
} |
||||
|
||||
// Frame returns the call frame infomation for the Call.
|
||||
func (c Call) Frame() runtime.Frame { |
||||
return c.frame |
||||
} |
||||
|
||||
// PC returns the program counter for this call frame; multiple frames may
|
||||
// have the same PC value.
|
||||
//
|
||||
// Deprecated: Use Call.Frame instead.
|
||||
func (c Call) PC() uintptr { |
||||
return c.frame.PC |
||||
} |
||||
|
||||
// CallStack records a sequence of function invocations from a goroutine
|
||||
// stack.
|
||||
type CallStack []Call |
||||
|
||||
// String implements fmt.Stinger. It is equivalent to fmt.Sprintf("%v", cs).
|
||||
func (cs CallStack) String() string { |
||||
return fmt.Sprint(cs) |
||||
} |
||||
|
||||
var ( |
||||
openBracketBytes = []byte("[") |
||||
closeBracketBytes = []byte("]") |
||||
spaceBytes = []byte(" ") |
||||
) |
||||
|
||||
// MarshalText implements encoding.TextMarshaler. It formats the CallStack the
|
||||
// same as fmt.Sprintf("%v", cs).
|
||||
func (cs CallStack) MarshalText() ([]byte, error) { |
||||
buf := bytes.Buffer{} |
||||
buf.Write(openBracketBytes) |
||||
for i, pc := range cs { |
||||
if i > 0 { |
||||
buf.Write(spaceBytes) |
||||
} |
||||
fmt.Fprint(&buf, pc) |
||||
} |
||||
buf.Write(closeBracketBytes) |
||||
return buf.Bytes(), nil |
||||
} |
||||
|
||||
// Format implements fmt.Formatter by printing the CallStack as square brackets
|
||||
// ([, ]) surrounding a space separated list of Calls each formatted with the
|
||||
// supplied verb and options.
|
||||
func (cs CallStack) Format(s fmt.State, verb rune) { |
||||
s.Write(openBracketBytes) |
||||
for i, pc := range cs { |
||||
if i > 0 { |
||||
s.Write(spaceBytes) |
||||
} |
||||
pc.Format(s, verb) |
||||
} |
||||
s.Write(closeBracketBytes) |
||||
} |
||||
|
||||
// Trace returns a CallStack for the current goroutine with element 0
|
||||
// identifying the calling function.
|
||||
func Trace() CallStack { |
||||
var pcs [512]uintptr |
||||
n := runtime.Callers(1, pcs[:]) |
||||
|
||||
frames := runtime.CallersFrames(pcs[:n]) |
||||
cs := make(CallStack, 0, n) |
||||
|
||||
// Skip extra frame retrieved just to make sure the runtime.sigpanic
|
||||
// special case is handled.
|
||||
frame, more := frames.Next() |
||||
|
||||
for more { |
||||
frame, more = frames.Next() |
||||
cs = append(cs, Call{frame: frame}) |
||||
} |
||||
|
||||
return cs |
||||
} |
||||
|
||||
// TrimBelow returns a slice of the CallStack with all entries below c
|
||||
// removed.
|
||||
func (cs CallStack) TrimBelow(c Call) CallStack { |
||||
for len(cs) > 0 && cs[0] != c { |
||||
cs = cs[1:] |
||||
} |
||||
return cs |
||||
} |
||||
|
||||
// TrimAbove returns a slice of the CallStack with all entries above c
|
||||
// removed.
|
||||
func (cs CallStack) TrimAbove(c Call) CallStack { |
||||
for len(cs) > 0 && cs[len(cs)-1] != c { |
||||
cs = cs[:len(cs)-1] |
||||
} |
||||
return cs |
||||
} |
||||
|
||||
// pkgIndex returns the index that results in file[index:] being the path of
|
||||
// file relative to the compile time GOPATH, and file[:index] being the
|
||||
// $GOPATH/src/ portion of file. funcName must be the name of a function in
|
||||
// file as returned by runtime.Func.Name.
|
||||
func pkgIndex(file, funcName string) int { |
||||
// As of Go 1.6.2 there is no direct way to know the compile time GOPATH
|
||||
// at runtime, but we can infer the number of path segments in the GOPATH.
|
||||
// We note that runtime.Func.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:
|
||||
//
|
||||
// file[:idx] == /home/user/src/
|
||||
// file[idx:] == pkg/sub/file.go
|
||||
//
|
||||
// From this we can easily see that fn.Name() has one less path separator
|
||||
// than our desired result for file[idx:]. 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 = "/" |
||||
i := len(file) |
||||
for n := strings.Count(funcName, sep) + 2; n > 0; n-- { |
||||
i = strings.LastIndex(file[:i], sep) |
||||
if i == -1 { |
||||
i = -len(sep) |
||||
break |
||||
} |
||||
} |
||||
// get back to 0 or trim the leading separator
|
||||
return i + len(sep) |
||||
} |
||||
|
||||
var runtimePath string |
||||
|
||||
func init() { |
||||
var pcs [3]uintptr |
||||
runtime.Callers(0, pcs[:]) |
||||
frames := runtime.CallersFrames(pcs[:]) |
||||
frame, _ := frames.Next() |
||||
file := frame.File |
||||
|
||||
idx := pkgIndex(frame.File, frame.Function) |
||||
|
||||
runtimePath = file[:idx] |
||||
if runtime.GOOS == "windows" { |
||||
runtimePath = strings.ToLower(runtimePath) |
||||
} |
||||
} |
||||
|
||||
func inGoroot(c Call) bool { |
||||
file := c.frame.File |
||||
if len(file) == 0 || file[0] == '?' { |
||||
return true |
||||
} |
||||
if runtime.GOOS == "windows" { |
||||
file = strings.ToLower(file) |
||||
} |
||||
return strings.HasPrefix(file, runtimePath) || strings.HasSuffix(file, "/_testmain.go") |
||||
} |
||||
|
||||
// TrimRuntime returns a slice of the CallStack with the topmost entries from
|
||||
// the go runtime removed. It considers any calls originating from unknown
|
||||
// files, files under GOROOT, or _testmain.go as part of the runtime.
|
||||
func (cs CallStack) TrimRuntime() CallStack { |
||||
for len(cs) > 0 && inGoroot(cs[len(cs)-1]) { |
||||
cs = cs[:len(cs)-1] |
||||
} |
||||
return cs |
||||
} |
Loading…
Reference in new issue