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// Copyright 2021 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Defensive debug-only utility to track that functions run on the
// goroutine that they're supposed to.
package checkpoint
import (
"bytes"
"errors"
"fmt"
"runtime"
"strconv"
"sync"
)
type goroutineLock uint64
func newGoroutineLock() goroutineLock {
if !DebugCheckpoint {
return 0
}
return goroutineLock(curGoroutineID())
}
func (g goroutineLock) check() {
if !DebugCheckpoint {
return
}
if curGoroutineID() != uint64(g) {
panic("running on the wrong goroutine")
}
}
var goroutineSpace = []byte("goroutine ")
func curGoroutineID() uint64 {
bp := littleBuf.Get().(*[]byte)
defer littleBuf.Put(bp)
b := *bp
b = b[:runtime.Stack(b, false)]
// Parse the 4707 out of "goroutine 4707 ["
b = bytes.TrimPrefix(b, goroutineSpace)
i := bytes.IndexByte(b, ' ')
if i < 0 {
panic(fmt.Sprintf("No space found in %q", b))
}
b = b[:i]
n, err := parseUintBytes(b, 10, 64)
if err != nil {
panic(fmt.Sprintf("Failed to parse goroutine ID out of %q: %v", b, err))
}
return n
}
var littleBuf = sync.Pool{
New: func() any {
buf := make([]byte, 64)
return &buf
},
}
// parseUintBytes is like strconv.ParseUint, but using a []byte.
func parseUintBytes(s []byte, base int, bitSize int) (n uint64, err error) {
var cutoff, maxVal uint64
if bitSize == 0 {
bitSize = int(strconv.IntSize)
}
s0 := s
switch {
case len(s) < 1:
err = strconv.ErrSyntax
goto Error
case 2 <= base && base <= 36:
// valid base; nothing to do
case base == 0:
// Look for octal, hex prefix.
switch {
case s[0] == '0' && len(s) > 1 && (s[1] == 'x' || s[1] == 'X'):
base = 16
s = s[2:]
if len(s) < 1 {
err = strconv.ErrSyntax
goto Error
}
case s[0] == '0':
base = 8
default:
base = 10
}
default:
err = errors.New("invalid base " + strconv.Itoa(base))
goto Error
}
n = 0
cutoff = cutoff64(base)
maxVal = 1<<uint(bitSize) - 1
for i := 0; i < len(s); i++ {
var v byte
d := s[i]
switch {
case '0' <= d && d <= '9':
v = d - '0'
case 'a' <= d && d <= 'z':
v = d - 'a' + 10
case 'A' <= d && d <= 'Z':
v = d - 'A' + 10
default:
n = 0
err = strconv.ErrSyntax
goto Error
}
if int(v) >= base {
n = 0
err = strconv.ErrSyntax
goto Error
}
if n >= cutoff {
// n*base overflows
n = 1<<64 - 1
err = strconv.ErrRange
goto Error
}
n *= uint64(base)
n1 := n + uint64(v)
if n1 < n || n1 > maxVal {
// n+v overflows
n = 1<<64 - 1
err = strconv.ErrRange
goto Error
}
n = n1
}
return n, nil
Error:
return n, &strconv.NumError{Func: "ParseUint", Num: string(s0), Err: err}
}
// Return the first number n such that n*base >= 1<<64.
func cutoff64(base int) uint64 {
if base < 2 {
return 0
}
return (1<<64-1)/uint64(base) + 1
}
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