gotosocial/vendor/github.com/godbus/dbus/v5/variant_parser.go
Daniele Sluijters acc333c40b
[feature] Inherit resource limits from cgroups (#1336)
When GTS is running in a container runtime which has configured CPU or
memory limits or under an init system that uses cgroups to impose CPU
and memory limits the values the Go runtime sees for GOMAXPROCS and
GOMEMLIMIT are still based on the host resources, not the cgroup.

At least for the throttling middlewares which use GOMAXPROCS to
configure their queue size, this can result in GTS running with values
too big compared to the resources that will actuall be available to it.

This introduces 2 dependencies which can pick up resource contraints
from the current cgroup and tune the Go runtime accordingly. This should
result in the different queues being appropriately sized and in general
more predictable performance. These dependencies are a no-op on
non-Linux systems or if running in a cgroup that doesn't set a limit on
CPU or memory.

The automatic tuning of GOMEMLIMIT can be disabled by either explicitly
setting GOMEMLIMIT yourself or by setting AUTOMEMLIMIT=off. The
automatic tuning of GOMAXPROCS can similarly be counteracted by setting
GOMAXPROCS yourself.
2023-01-17 20:59:04 +00:00

817 lines
15 KiB
Go

package dbus
import (
"bytes"
"errors"
"fmt"
"io"
"reflect"
"strconv"
"strings"
"unicode/utf8"
)
type varParser struct {
tokens []varToken
i int
}
func (p *varParser) backup() {
p.i--
}
func (p *varParser) next() varToken {
if p.i < len(p.tokens) {
t := p.tokens[p.i]
p.i++
return t
}
return varToken{typ: tokEOF}
}
type varNode interface {
Infer() (Signature, error)
String() string
Sigs() sigSet
Value(Signature) (interface{}, error)
}
func varMakeNode(p *varParser) (varNode, error) {
var sig Signature
for {
t := p.next()
switch t.typ {
case tokEOF:
return nil, io.ErrUnexpectedEOF
case tokError:
return nil, errors.New(t.val)
case tokNumber:
return varMakeNumNode(t, sig)
case tokString:
return varMakeStringNode(t, sig)
case tokBool:
if sig.str != "" && sig.str != "b" {
return nil, varTypeError{t.val, sig}
}
b, err := strconv.ParseBool(t.val)
if err != nil {
return nil, err
}
return boolNode(b), nil
case tokArrayStart:
return varMakeArrayNode(p, sig)
case tokVariantStart:
return varMakeVariantNode(p, sig)
case tokDictStart:
return varMakeDictNode(p, sig)
case tokType:
if sig.str != "" {
return nil, errors.New("unexpected type annotation")
}
if t.val[0] == '@' {
sig.str = t.val[1:]
} else {
sig.str = varTypeMap[t.val]
}
case tokByteString:
if sig.str != "" && sig.str != "ay" {
return nil, varTypeError{t.val, sig}
}
b, err := varParseByteString(t.val)
if err != nil {
return nil, err
}
return byteStringNode(b), nil
default:
return nil, fmt.Errorf("unexpected %q", t.val)
}
}
}
type varTypeError struct {
val string
sig Signature
}
func (e varTypeError) Error() string {
return fmt.Sprintf("dbus: can't parse %q as type %q", e.val, e.sig.str)
}
type sigSet map[Signature]bool
func (s sigSet) Empty() bool {
return len(s) == 0
}
func (s sigSet) Intersect(s2 sigSet) sigSet {
r := make(sigSet)
for k := range s {
if s2[k] {
r[k] = true
}
}
return r
}
func (s sigSet) Single() (Signature, bool) {
if len(s) == 1 {
for k := range s {
return k, true
}
}
return Signature{}, false
}
func (s sigSet) ToArray() sigSet {
r := make(sigSet, len(s))
for k := range s {
r[Signature{"a" + k.str}] = true
}
return r
}
type numNode struct {
sig Signature
str string
val interface{}
}
var numSigSet = sigSet{
Signature{"y"}: true,
Signature{"n"}: true,
Signature{"q"}: true,
Signature{"i"}: true,
Signature{"u"}: true,
Signature{"x"}: true,
Signature{"t"}: true,
Signature{"d"}: true,
}
func (n numNode) Infer() (Signature, error) {
if strings.ContainsAny(n.str, ".e") {
return Signature{"d"}, nil
}
return Signature{"i"}, nil
}
func (n numNode) String() string {
return n.str
}
func (n numNode) Sigs() sigSet {
if n.sig.str != "" {
return sigSet{n.sig: true}
}
if strings.ContainsAny(n.str, ".e") {
return sigSet{Signature{"d"}: true}
}
return numSigSet
}
func (n numNode) Value(sig Signature) (interface{}, error) {
if n.sig.str != "" && n.sig != sig {
return nil, varTypeError{n.str, sig}
}
if n.val != nil {
return n.val, nil
}
return varNumAs(n.str, sig)
}
func varMakeNumNode(tok varToken, sig Signature) (varNode, error) {
if sig.str == "" {
return numNode{str: tok.val}, nil
}
num, err := varNumAs(tok.val, sig)
if err != nil {
return nil, err
}
return numNode{sig: sig, val: num}, nil
}
func varNumAs(s string, sig Signature) (interface{}, error) {
isUnsigned := false
size := 32
switch sig.str {
case "n":
size = 16
case "i":
case "x":
size = 64
case "y":
size = 8
isUnsigned = true
case "q":
size = 16
isUnsigned = true
case "u":
isUnsigned = true
case "t":
size = 64
isUnsigned = true
case "d":
d, err := strconv.ParseFloat(s, 64)
if err != nil {
return nil, err
}
return d, nil
default:
return nil, varTypeError{s, sig}
}
base := 10
if strings.HasPrefix(s, "0x") {
base = 16
s = s[2:]
}
if strings.HasPrefix(s, "0") && len(s) != 1 {
base = 8
s = s[1:]
}
if isUnsigned {
i, err := strconv.ParseUint(s, base, size)
if err != nil {
return nil, err
}
var v interface{} = i
switch sig.str {
case "y":
v = byte(i)
case "q":
v = uint16(i)
case "u":
v = uint32(i)
}
return v, nil
}
i, err := strconv.ParseInt(s, base, size)
if err != nil {
return nil, err
}
var v interface{} = i
switch sig.str {
case "n":
v = int16(i)
case "i":
v = int32(i)
}
return v, nil
}
type stringNode struct {
sig Signature
str string // parsed
val interface{} // has correct type
}
var stringSigSet = sigSet{
Signature{"s"}: true,
Signature{"g"}: true,
Signature{"o"}: true,
}
func (n stringNode) Infer() (Signature, error) {
return Signature{"s"}, nil
}
func (n stringNode) String() string {
return n.str
}
func (n stringNode) Sigs() sigSet {
if n.sig.str != "" {
return sigSet{n.sig: true}
}
return stringSigSet
}
func (n stringNode) Value(sig Signature) (interface{}, error) {
if n.sig.str != "" && n.sig != sig {
return nil, varTypeError{n.str, sig}
}
if n.val != nil {
return n.val, nil
}
switch {
case sig.str == "g":
return Signature{n.str}, nil
case sig.str == "o":
return ObjectPath(n.str), nil
case sig.str == "s":
return n.str, nil
default:
return nil, varTypeError{n.str, sig}
}
}
func varMakeStringNode(tok varToken, sig Signature) (varNode, error) {
if sig.str != "" && sig.str != "s" && sig.str != "g" && sig.str != "o" {
return nil, fmt.Errorf("invalid type %q for string", sig.str)
}
s, err := varParseString(tok.val)
if err != nil {
return nil, err
}
n := stringNode{str: s}
if sig.str == "" {
return stringNode{str: s}, nil
}
n.sig = sig
switch sig.str {
case "o":
n.val = ObjectPath(s)
case "g":
n.val = Signature{s}
case "s":
n.val = s
}
return n, nil
}
func varParseString(s string) (string, error) {
// quotes are guaranteed to be there
s = s[1 : len(s)-1]
buf := new(bytes.Buffer)
for len(s) != 0 {
r, size := utf8.DecodeRuneInString(s)
if r == utf8.RuneError && size == 1 {
return "", errors.New("invalid UTF-8")
}
s = s[size:]
if r != '\\' {
buf.WriteRune(r)
continue
}
r, size = utf8.DecodeRuneInString(s)
if r == utf8.RuneError && size == 1 {
return "", errors.New("invalid UTF-8")
}
s = s[size:]
switch r {
case 'a':
buf.WriteRune(0x7)
case 'b':
buf.WriteRune(0x8)
case 'f':
buf.WriteRune(0xc)
case 'n':
buf.WriteRune('\n')
case 'r':
buf.WriteRune('\r')
case 't':
buf.WriteRune('\t')
case '\n':
case 'u':
if len(s) < 4 {
return "", errors.New("short unicode escape")
}
r, err := strconv.ParseUint(s[:4], 16, 32)
if err != nil {
return "", err
}
buf.WriteRune(rune(r))
s = s[4:]
case 'U':
if len(s) < 8 {
return "", errors.New("short unicode escape")
}
r, err := strconv.ParseUint(s[:8], 16, 32)
if err != nil {
return "", err
}
buf.WriteRune(rune(r))
s = s[8:]
default:
buf.WriteRune(r)
}
}
return buf.String(), nil
}
var boolSigSet = sigSet{Signature{"b"}: true}
type boolNode bool
func (boolNode) Infer() (Signature, error) {
return Signature{"b"}, nil
}
func (b boolNode) String() string {
if b {
return "true"
}
return "false"
}
func (boolNode) Sigs() sigSet {
return boolSigSet
}
func (b boolNode) Value(sig Signature) (interface{}, error) {
if sig.str != "b" {
return nil, varTypeError{b.String(), sig}
}
return bool(b), nil
}
type arrayNode struct {
set sigSet
children []varNode
val interface{}
}
func (n arrayNode) Infer() (Signature, error) {
for _, v := range n.children {
csig, err := varInfer(v)
if err != nil {
continue
}
return Signature{"a" + csig.str}, nil
}
return Signature{}, fmt.Errorf("can't infer type for %q", n.String())
}
func (n arrayNode) String() string {
s := "["
for i, v := range n.children {
s += v.String()
if i != len(n.children)-1 {
s += ", "
}
}
return s + "]"
}
func (n arrayNode) Sigs() sigSet {
return n.set
}
func (n arrayNode) Value(sig Signature) (interface{}, error) {
if n.set.Empty() {
// no type information whatsoever, so this must be an empty slice
return reflect.MakeSlice(typeFor(sig.str), 0, 0).Interface(), nil
}
if !n.set[sig] {
return nil, varTypeError{n.String(), sig}
}
s := reflect.MakeSlice(typeFor(sig.str), len(n.children), len(n.children))
for i, v := range n.children {
rv, err := v.Value(Signature{sig.str[1:]})
if err != nil {
return nil, err
}
s.Index(i).Set(reflect.ValueOf(rv))
}
return s.Interface(), nil
}
func varMakeArrayNode(p *varParser, sig Signature) (varNode, error) {
var n arrayNode
if sig.str != "" {
n.set = sigSet{sig: true}
}
if t := p.next(); t.typ == tokArrayEnd {
return n, nil
} else {
p.backup()
}
Loop:
for {
t := p.next()
switch t.typ {
case tokEOF:
return nil, io.ErrUnexpectedEOF
case tokError:
return nil, errors.New(t.val)
}
p.backup()
cn, err := varMakeNode(p)
if err != nil {
return nil, err
}
if cset := cn.Sigs(); !cset.Empty() {
if n.set.Empty() {
n.set = cset.ToArray()
} else {
nset := cset.ToArray().Intersect(n.set)
if nset.Empty() {
return nil, fmt.Errorf("can't parse %q with given type information", cn.String())
}
n.set = nset
}
}
n.children = append(n.children, cn)
switch t := p.next(); t.typ {
case tokEOF:
return nil, io.ErrUnexpectedEOF
case tokError:
return nil, errors.New(t.val)
case tokArrayEnd:
break Loop
case tokComma:
continue
default:
return nil, fmt.Errorf("unexpected %q", t.val)
}
}
return n, nil
}
type variantNode struct {
n varNode
}
var variantSet = sigSet{
Signature{"v"}: true,
}
func (variantNode) Infer() (Signature, error) {
return Signature{"v"}, nil
}
func (n variantNode) String() string {
return "<" + n.n.String() + ">"
}
func (variantNode) Sigs() sigSet {
return variantSet
}
func (n variantNode) Value(sig Signature) (interface{}, error) {
if sig.str != "v" {
return nil, varTypeError{n.String(), sig}
}
sig, err := varInfer(n.n)
if err != nil {
return nil, err
}
v, err := n.n.Value(sig)
if err != nil {
return nil, err
}
return MakeVariant(v), nil
}
func varMakeVariantNode(p *varParser, sig Signature) (varNode, error) {
n, err := varMakeNode(p)
if err != nil {
return nil, err
}
if t := p.next(); t.typ != tokVariantEnd {
return nil, fmt.Errorf("unexpected %q", t.val)
}
vn := variantNode{n}
if sig.str != "" && sig.str != "v" {
return nil, varTypeError{vn.String(), sig}
}
return variantNode{n}, nil
}
type dictEntry struct {
key, val varNode
}
type dictNode struct {
kset, vset sigSet
children []dictEntry
val interface{}
}
func (n dictNode) Infer() (Signature, error) {
for _, v := range n.children {
ksig, err := varInfer(v.key)
if err != nil {
continue
}
vsig, err := varInfer(v.val)
if err != nil {
continue
}
return Signature{"a{" + ksig.str + vsig.str + "}"}, nil
}
return Signature{}, fmt.Errorf("can't infer type for %q", n.String())
}
func (n dictNode) String() string {
s := "{"
for i, v := range n.children {
s += v.key.String() + ": " + v.val.String()
if i != len(n.children)-1 {
s += ", "
}
}
return s + "}"
}
func (n dictNode) Sigs() sigSet {
r := sigSet{}
for k := range n.kset {
for v := range n.vset {
sig := "a{" + k.str + v.str + "}"
r[Signature{sig}] = true
}
}
return r
}
func (n dictNode) Value(sig Signature) (interface{}, error) {
set := n.Sigs()
if set.Empty() {
// no type information -> empty dict
return reflect.MakeMap(typeFor(sig.str)).Interface(), nil
}
if !set[sig] {
return nil, varTypeError{n.String(), sig}
}
m := reflect.MakeMap(typeFor(sig.str))
ksig := Signature{sig.str[2:3]}
vsig := Signature{sig.str[3 : len(sig.str)-1]}
for _, v := range n.children {
kv, err := v.key.Value(ksig)
if err != nil {
return nil, err
}
vv, err := v.val.Value(vsig)
if err != nil {
return nil, err
}
m.SetMapIndex(reflect.ValueOf(kv), reflect.ValueOf(vv))
}
return m.Interface(), nil
}
func varMakeDictNode(p *varParser, sig Signature) (varNode, error) {
var n dictNode
if sig.str != "" {
if len(sig.str) < 5 {
return nil, fmt.Errorf("invalid signature %q for dict type", sig)
}
ksig := Signature{string(sig.str[2])}
vsig := Signature{sig.str[3 : len(sig.str)-1]}
n.kset = sigSet{ksig: true}
n.vset = sigSet{vsig: true}
}
if t := p.next(); t.typ == tokDictEnd {
return n, nil
} else {
p.backup()
}
Loop:
for {
t := p.next()
switch t.typ {
case tokEOF:
return nil, io.ErrUnexpectedEOF
case tokError:
return nil, errors.New(t.val)
}
p.backup()
kn, err := varMakeNode(p)
if err != nil {
return nil, err
}
if kset := kn.Sigs(); !kset.Empty() {
if n.kset.Empty() {
n.kset = kset
} else {
n.kset = kset.Intersect(n.kset)
if n.kset.Empty() {
return nil, fmt.Errorf("can't parse %q with given type information", kn.String())
}
}
}
t = p.next()
switch t.typ {
case tokEOF:
return nil, io.ErrUnexpectedEOF
case tokError:
return nil, errors.New(t.val)
case tokColon:
default:
return nil, fmt.Errorf("unexpected %q", t.val)
}
t = p.next()
switch t.typ {
case tokEOF:
return nil, io.ErrUnexpectedEOF
case tokError:
return nil, errors.New(t.val)
}
p.backup()
vn, err := varMakeNode(p)
if err != nil {
return nil, err
}
if vset := vn.Sigs(); !vset.Empty() {
if n.vset.Empty() {
n.vset = vset
} else {
n.vset = n.vset.Intersect(vset)
if n.vset.Empty() {
return nil, fmt.Errorf("can't parse %q with given type information", vn.String())
}
}
}
n.children = append(n.children, dictEntry{kn, vn})
t = p.next()
switch t.typ {
case tokEOF:
return nil, io.ErrUnexpectedEOF
case tokError:
return nil, errors.New(t.val)
case tokDictEnd:
break Loop
case tokComma:
continue
default:
return nil, fmt.Errorf("unexpected %q", t.val)
}
}
return n, nil
}
type byteStringNode []byte
var byteStringSet = sigSet{
Signature{"ay"}: true,
}
func (byteStringNode) Infer() (Signature, error) {
return Signature{"ay"}, nil
}
func (b byteStringNode) String() string {
return string(b)
}
func (b byteStringNode) Sigs() sigSet {
return byteStringSet
}
func (b byteStringNode) Value(sig Signature) (interface{}, error) {
if sig.str != "ay" {
return nil, varTypeError{b.String(), sig}
}
return []byte(b), nil
}
func varParseByteString(s string) ([]byte, error) {
// quotes and b at start are guaranteed to be there
b := make([]byte, 0, 1)
s = s[2 : len(s)-1]
for len(s) != 0 {
c := s[0]
s = s[1:]
if c != '\\' {
b = append(b, c)
continue
}
c = s[0]
s = s[1:]
switch c {
case 'a':
b = append(b, 0x7)
case 'b':
b = append(b, 0x8)
case 'f':
b = append(b, 0xc)
case 'n':
b = append(b, '\n')
case 'r':
b = append(b, '\r')
case 't':
b = append(b, '\t')
case 'x':
if len(s) < 2 {
return nil, errors.New("short escape")
}
n, err := strconv.ParseUint(s[:2], 16, 8)
if err != nil {
return nil, err
}
b = append(b, byte(n))
s = s[2:]
case '0':
if len(s) < 3 {
return nil, errors.New("short escape")
}
n, err := strconv.ParseUint(s[:3], 8, 8)
if err != nil {
return nil, err
}
b = append(b, byte(n))
s = s[3:]
default:
b = append(b, c)
}
}
return append(b, 0), nil
}
func varInfer(n varNode) (Signature, error) {
if sig, ok := n.Sigs().Single(); ok {
return sig, nil
}
return n.Infer()
}