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Scott Bakere7144bc2019-10-01 14:16:47 -07001// Copyright (c) 2016 Uber Technologies, Inc.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a copy
4// of this software and associated documentation files (the "Software"), to deal
5// in the Software without restriction, including without limitation the rights
6// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7// copies of the Software, and to permit persons to whom the Software is
8// furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19// THE SOFTWARE.
20
21package zap
22
23import (
24 "runtime"
25 "strings"
26 "sync"
27
28 "go.uber.org/zap/internal/bufferpool"
29)
30
31const _zapPackage = "go.uber.org/zap"
32
33var (
34 _stacktracePool = sync.Pool{
35 New: func() interface{} {
36 return newProgramCounters(64)
37 },
38 }
39
40 // We add "." and "/" suffixes to the package name to ensure we only match
41 // the exact package and not any package with the same prefix.
42 _zapStacktracePrefixes = addPrefix(_zapPackage, ".", "/")
43 _zapStacktraceVendorContains = addPrefix("/vendor/", _zapStacktracePrefixes...)
44)
45
46func takeStacktrace() string {
47 buffer := bufferpool.Get()
48 defer buffer.Free()
49 programCounters := _stacktracePool.Get().(*programCounters)
50 defer _stacktracePool.Put(programCounters)
51
52 var numFrames int
53 for {
54 // Skip the call to runtime.Counters and takeStacktrace so that the
55 // program counters start at the caller of takeStacktrace.
56 numFrames = runtime.Callers(2, programCounters.pcs)
57 if numFrames < len(programCounters.pcs) {
58 break
59 }
60 // Don't put the too-short counter slice back into the pool; this lets
61 // the pool adjust if we consistently take deep stacktraces.
62 programCounters = newProgramCounters(len(programCounters.pcs) * 2)
63 }
64
65 i := 0
66 skipZapFrames := true // skip all consecutive zap frames at the beginning.
67 frames := runtime.CallersFrames(programCounters.pcs[:numFrames])
68
69 // Note: On the last iteration, frames.Next() returns false, with a valid
70 // frame, but we ignore this frame. The last frame is a a runtime frame which
71 // adds noise, since it's only either runtime.main or runtime.goexit.
72 for frame, more := frames.Next(); more; frame, more = frames.Next() {
73 if skipZapFrames && isZapFrame(frame.Function) {
74 continue
75 } else {
76 skipZapFrames = false
77 }
78
79 if i != 0 {
80 buffer.AppendByte('\n')
81 }
82 i++
83 buffer.AppendString(frame.Function)
84 buffer.AppendByte('\n')
85 buffer.AppendByte('\t')
86 buffer.AppendString(frame.File)
87 buffer.AppendByte(':')
88 buffer.AppendInt(int64(frame.Line))
89 }
90
91 return buffer.String()
92}
93
94func isZapFrame(function string) bool {
95 for _, prefix := range _zapStacktracePrefixes {
96 if strings.HasPrefix(function, prefix) {
97 return true
98 }
99 }
100
101 // We can't use a prefix match here since the location of the vendor
102 // directory affects the prefix. Instead we do a contains match.
103 for _, contains := range _zapStacktraceVendorContains {
104 if strings.Contains(function, contains) {
105 return true
106 }
107 }
108
109 return false
110}
111
112type programCounters struct {
113 pcs []uintptr
114}
115
116func newProgramCounters(size int) *programCounters {
117 return &programCounters{make([]uintptr, size)}
118}
119
120func addPrefix(prefix string, ss ...string) []string {
121 withPrefix := make([]string, len(ss))
122 for i, s := range ss {
123 withPrefix[i] = prefix + s
124 }
125 return withPrefix
126}