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// Copyright (c) 2016 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package zap
import (
"runtime"
"strings"
"sync"
"go.uber.org/zap/internal/bufferpool"
)
const _zapPackage = "go.uber.org/zap"
var (
_stacktracePool = sync.Pool{
New: func() interface{} {
return newProgramCounters(64)
},
}
// We add "." and "/" suffixes to the package name to ensure we only match
// the exact package and not any package with the same prefix.
_zapStacktracePrefixes = addPrefix(_zapPackage, ".", "/")
_zapStacktraceVendorContains = addPrefix("/vendor/", _zapStacktracePrefixes...)
)
func takeStacktrace() string {
buffer := bufferpool.Get()
defer buffer.Free()
programCounters := _stacktracePool.Get().(*programCounters)
defer _stacktracePool.Put(programCounters)
var numFrames int
for {
// Skip the call to runtime.Counters and takeStacktrace so that the
// program counters start at the caller of takeStacktrace.
numFrames = runtime.Callers(2, programCounters.pcs)
if numFrames < len(programCounters.pcs) {
break
}
// Don't put the too-short counter slice back into the pool; this lets
// the pool adjust if we consistently take deep stacktraces.
programCounters = newProgramCounters(len(programCounters.pcs) * 2)
}
i := 0
skipZapFrames := true // skip all consecutive zap frames at the beginning.
frames := runtime.CallersFrames(programCounters.pcs[:numFrames])
// Note: On the last iteration, frames.Next() returns false, with a valid
// frame, but we ignore this frame. The last frame is a a runtime frame which
// adds noise, since it's only either runtime.main or runtime.goexit.
for frame, more := frames.Next(); more; frame, more = frames.Next() {
if skipZapFrames && isZapFrame(frame.Function) {
continue
} else {
skipZapFrames = false
}
if i != 0 {
buffer.AppendByte('\n')
}
i++
buffer.AppendString(frame.Function)
buffer.AppendByte('\n')
buffer.AppendByte('\t')
buffer.AppendString(frame.File)
buffer.AppendByte(':')
buffer.AppendInt(int64(frame.Line))
}
return buffer.String()
}
func isZapFrame(function string) bool {
for _, prefix := range _zapStacktracePrefixes {
if strings.HasPrefix(function, prefix) {
return true
}
}
// We can't use a prefix match here since the location of the vendor
// directory affects the prefix. Instead we do a contains match.
for _, contains := range _zapStacktraceVendorContains {
if strings.Contains(function, contains) {
return true
}
}
return false
}
type programCounters struct {
pcs []uintptr
}
func newProgramCounters(size int) *programCounters {
return &programCounters{make([]uintptr, size)}
}
func addPrefix(prefix string, ss ...string) []string {
withPrefix := make([]string, len(ss))
for i, s := range ss {
withPrefix[i] = prefix + s
}
return withPrefix
}