mirror of
https://github.com/prometheus/prometheus
synced 2024-12-23 15:04:13 +00:00
31c5760551
unsafe.Slice and unsafe.StringData were added in Go 1.20 Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
694 lines
18 KiB
Go
694 lines
18 KiB
Go
// Copyright 2017 The Prometheus Authors
|
|
// 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,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
//go:build stringlabels
|
|
|
|
package labels
|
|
|
|
import (
|
|
"slices"
|
|
"strings"
|
|
"unsafe"
|
|
|
|
"github.com/cespare/xxhash/v2"
|
|
)
|
|
|
|
// Labels is implemented by a single flat string holding name/value pairs.
|
|
// Each name and value is preceded by its length in varint encoding.
|
|
// Names are in order.
|
|
type Labels struct {
|
|
data string
|
|
}
|
|
|
|
func decodeSize(data string, index int) (int, int) {
|
|
// Fast-path for common case of a single byte, value 0..127.
|
|
b := data[index]
|
|
index++
|
|
if b < 0x80 {
|
|
return int(b), index
|
|
}
|
|
size := int(b & 0x7F)
|
|
for shift := uint(7); ; shift += 7 {
|
|
// Just panic if we go of the end of data, since all Labels strings are constructed internally and
|
|
// malformed data indicates a bug, or memory corruption.
|
|
b := data[index]
|
|
index++
|
|
size |= int(b&0x7F) << shift
|
|
if b < 0x80 {
|
|
break
|
|
}
|
|
}
|
|
return size, index
|
|
}
|
|
|
|
func decodeString(data string, index int) (string, int) {
|
|
var size int
|
|
size, index = decodeSize(data, index)
|
|
return data[index : index+size], index + size
|
|
}
|
|
|
|
// Bytes returns ls as a byte slice.
|
|
// It uses non-printing characters and so should not be used for printing.
|
|
func (ls Labels) Bytes(buf []byte) []byte {
|
|
if cap(buf) < len(ls.data) {
|
|
buf = make([]byte, len(ls.data))
|
|
} else {
|
|
buf = buf[:len(ls.data)]
|
|
}
|
|
copy(buf, ls.data)
|
|
return buf
|
|
}
|
|
|
|
// IsZero implements yaml.IsZeroer - if we don't have this then 'omitempty' fields are always omitted.
|
|
func (ls Labels) IsZero() bool {
|
|
return len(ls.data) == 0
|
|
}
|
|
|
|
// MatchLabels returns a subset of Labels that matches/does not match with the provided label names based on the 'on' boolean.
|
|
// If on is set to true, it returns the subset of labels that match with the provided label names and its inverse when 'on' is set to false.
|
|
// TODO: This is only used in printing an error message
|
|
func (ls Labels) MatchLabels(on bool, names ...string) Labels {
|
|
b := NewBuilder(ls)
|
|
if on {
|
|
b.Keep(names...)
|
|
} else {
|
|
b.Del(MetricName)
|
|
b.Del(names...)
|
|
}
|
|
return b.Labels()
|
|
}
|
|
|
|
// Hash returns a hash value for the label set.
|
|
// Note: the result is not guaranteed to be consistent across different runs of Prometheus.
|
|
func (ls Labels) Hash() uint64 {
|
|
return xxhash.Sum64(yoloBytes(ls.data))
|
|
}
|
|
|
|
// HashForLabels returns a hash value for the labels matching the provided names.
|
|
// 'names' have to be sorted in ascending order.
|
|
func (ls Labels) HashForLabels(b []byte, names ...string) (uint64, []byte) {
|
|
b = b[:0]
|
|
j := 0
|
|
for i := 0; i < len(ls.data); {
|
|
var name, value string
|
|
name, i = decodeString(ls.data, i)
|
|
value, i = decodeString(ls.data, i)
|
|
for j < len(names) && names[j] < name {
|
|
j++
|
|
}
|
|
if j == len(names) {
|
|
break
|
|
}
|
|
if name == names[j] {
|
|
b = append(b, name...)
|
|
b = append(b, sep)
|
|
b = append(b, value...)
|
|
b = append(b, sep)
|
|
}
|
|
}
|
|
|
|
return xxhash.Sum64(b), b
|
|
}
|
|
|
|
// HashWithoutLabels returns a hash value for all labels except those matching
|
|
// the provided names.
|
|
// 'names' have to be sorted in ascending order.
|
|
func (ls Labels) HashWithoutLabels(b []byte, names ...string) (uint64, []byte) {
|
|
b = b[:0]
|
|
j := 0
|
|
for i := 0; i < len(ls.data); {
|
|
var name, value string
|
|
name, i = decodeString(ls.data, i)
|
|
value, i = decodeString(ls.data, i)
|
|
for j < len(names) && names[j] < name {
|
|
j++
|
|
}
|
|
if name == MetricName || (j < len(names) && name == names[j]) {
|
|
continue
|
|
}
|
|
b = append(b, name...)
|
|
b = append(b, sep)
|
|
b = append(b, value...)
|
|
b = append(b, sep)
|
|
}
|
|
return xxhash.Sum64(b), b
|
|
}
|
|
|
|
// BytesWithLabels is just as Bytes(), but only for labels matching names.
|
|
// 'names' have to be sorted in ascending order.
|
|
func (ls Labels) BytesWithLabels(buf []byte, names ...string) []byte {
|
|
b := buf[:0]
|
|
j := 0
|
|
for pos := 0; pos < len(ls.data); {
|
|
lName, newPos := decodeString(ls.data, pos)
|
|
_, newPos = decodeString(ls.data, newPos)
|
|
for j < len(names) && names[j] < lName {
|
|
j++
|
|
}
|
|
if j == len(names) {
|
|
break
|
|
}
|
|
if lName == names[j] {
|
|
b = append(b, ls.data[pos:newPos]...)
|
|
}
|
|
pos = newPos
|
|
}
|
|
return b
|
|
}
|
|
|
|
// BytesWithoutLabels is just as Bytes(), but only for labels not matching names.
|
|
// 'names' have to be sorted in ascending order.
|
|
func (ls Labels) BytesWithoutLabels(buf []byte, names ...string) []byte {
|
|
b := buf[:0]
|
|
j := 0
|
|
for pos := 0; pos < len(ls.data); {
|
|
lName, newPos := decodeString(ls.data, pos)
|
|
_, newPos = decodeString(ls.data, newPos)
|
|
for j < len(names) && names[j] < lName {
|
|
j++
|
|
}
|
|
if j == len(names) || lName != names[j] {
|
|
b = append(b, ls.data[pos:newPos]...)
|
|
}
|
|
pos = newPos
|
|
}
|
|
return b
|
|
}
|
|
|
|
// Copy returns a copy of the labels.
|
|
func (ls Labels) Copy() Labels {
|
|
return Labels{data: strings.Clone(ls.data)}
|
|
}
|
|
|
|
// Get returns the value for the label with the given name.
|
|
// Returns an empty string if the label doesn't exist.
|
|
func (ls Labels) Get(name string) string {
|
|
if name == "" { // Avoid crash in loop if someone asks for "".
|
|
return "" // Prometheus does not store blank label names.
|
|
}
|
|
for i := 0; i < len(ls.data); {
|
|
var size int
|
|
size, i = decodeSize(ls.data, i)
|
|
if ls.data[i] == name[0] {
|
|
lName := ls.data[i : i+size]
|
|
i += size
|
|
if lName == name {
|
|
lValue, _ := decodeString(ls.data, i)
|
|
return lValue
|
|
}
|
|
} else {
|
|
if ls.data[i] > name[0] { // Stop looking if we've gone past.
|
|
break
|
|
}
|
|
i += size
|
|
}
|
|
size, i = decodeSize(ls.data, i)
|
|
i += size
|
|
}
|
|
return ""
|
|
}
|
|
|
|
// Has returns true if the label with the given name is present.
|
|
func (ls Labels) Has(name string) bool {
|
|
if name == "" { // Avoid crash in loop if someone asks for "".
|
|
return false // Prometheus does not store blank label names.
|
|
}
|
|
for i := 0; i < len(ls.data); {
|
|
var size int
|
|
size, i = decodeSize(ls.data, i)
|
|
if ls.data[i] == name[0] {
|
|
lName := ls.data[i : i+size]
|
|
i += size
|
|
if lName == name {
|
|
return true
|
|
}
|
|
} else {
|
|
if ls.data[i] > name[0] { // Stop looking if we've gone past.
|
|
break
|
|
}
|
|
i += size
|
|
}
|
|
size, i = decodeSize(ls.data, i)
|
|
i += size
|
|
}
|
|
return false
|
|
}
|
|
|
|
// HasDuplicateLabelNames returns whether ls has duplicate label names.
|
|
// It assumes that the labelset is sorted.
|
|
func (ls Labels) HasDuplicateLabelNames() (string, bool) {
|
|
var lName, prevName string
|
|
for i := 0; i < len(ls.data); {
|
|
lName, i = decodeString(ls.data, i)
|
|
_, i = decodeString(ls.data, i)
|
|
if lName == prevName {
|
|
return lName, true
|
|
}
|
|
prevName = lName
|
|
}
|
|
return "", false
|
|
}
|
|
|
|
// WithoutEmpty returns the labelset without empty labels.
|
|
// May return the same labelset.
|
|
func (ls Labels) WithoutEmpty() Labels {
|
|
for pos := 0; pos < len(ls.data); {
|
|
_, newPos := decodeString(ls.data, pos)
|
|
lValue, newPos := decodeString(ls.data, newPos)
|
|
if lValue != "" {
|
|
pos = newPos
|
|
continue
|
|
}
|
|
// Do not copy the slice until it's necessary.
|
|
// TODO: could optimise the case where all blanks are at the end.
|
|
// Note: we size the new buffer on the assumption there is exactly one blank value.
|
|
buf := make([]byte, pos, pos+(len(ls.data)-newPos))
|
|
copy(buf, ls.data[:pos]) // copy the initial non-blank labels
|
|
pos = newPos // move past the first blank value
|
|
for pos < len(ls.data) {
|
|
var newPos int
|
|
_, newPos = decodeString(ls.data, pos)
|
|
lValue, newPos = decodeString(ls.data, newPos)
|
|
if lValue != "" {
|
|
buf = append(buf, ls.data[pos:newPos]...)
|
|
}
|
|
pos = newPos
|
|
}
|
|
return Labels{data: yoloString(buf)}
|
|
}
|
|
return ls
|
|
}
|
|
|
|
// Equal returns whether the two label sets are equal.
|
|
func Equal(ls, o Labels) bool {
|
|
return ls.data == o.data
|
|
}
|
|
|
|
// EmptyLabels returns an empty Labels value, for convenience.
|
|
func EmptyLabels() Labels {
|
|
return Labels{}
|
|
}
|
|
func yoloBytes(s string) []byte {
|
|
return unsafe.Slice(unsafe.StringData(s), len(s))
|
|
}
|
|
|
|
// New returns a sorted Labels from the given labels.
|
|
// The caller has to guarantee that all label names are unique.
|
|
func New(ls ...Label) Labels {
|
|
slices.SortFunc(ls, func(a, b Label) int { return strings.Compare(a.Name, b.Name) })
|
|
size := labelsSize(ls)
|
|
buf := make([]byte, size)
|
|
marshalLabelsToSizedBuffer(ls, buf)
|
|
return Labels{data: yoloString(buf)}
|
|
}
|
|
|
|
// FromStrings creates new labels from pairs of strings.
|
|
func FromStrings(ss ...string) Labels {
|
|
if len(ss)%2 != 0 {
|
|
panic("invalid number of strings")
|
|
}
|
|
ls := make([]Label, 0, len(ss)/2)
|
|
for i := 0; i < len(ss); i += 2 {
|
|
ls = append(ls, Label{Name: ss[i], Value: ss[i+1]})
|
|
}
|
|
|
|
return New(ls...)
|
|
}
|
|
|
|
// Compare compares the two label sets.
|
|
// The result will be 0 if a==b, <0 if a < b, and >0 if a > b.
|
|
func Compare(a, b Labels) int {
|
|
// Find the first byte in the string where a and b differ.
|
|
shorter, longer := a.data, b.data
|
|
if len(b.data) < len(a.data) {
|
|
shorter, longer = b.data, a.data
|
|
}
|
|
i := 0
|
|
// First, go 8 bytes at a time. Data strings are expected to be 8-byte aligned.
|
|
sp := unsafe.Pointer(unsafe.StringData(shorter))
|
|
lp := unsafe.Pointer(unsafe.StringData(longer))
|
|
for ; i < len(shorter)-8; i += 8 {
|
|
if *(*uint64)(unsafe.Add(sp, i)) != *(*uint64)(unsafe.Add(lp, i)) {
|
|
break
|
|
}
|
|
}
|
|
// Now go 1 byte at a time.
|
|
for ; i < len(shorter); i++ {
|
|
if shorter[i] != longer[i] {
|
|
break
|
|
}
|
|
}
|
|
if i == len(shorter) {
|
|
// One Labels was a prefix of the other; the set with fewer labels compares lower.
|
|
return len(a.data) - len(b.data)
|
|
}
|
|
|
|
// Now we know that there is some difference before the end of a and b.
|
|
// Go back through the fields and find which field that difference is in.
|
|
firstCharDifferent, i := i, 0
|
|
size, nextI := decodeSize(a.data, i)
|
|
for nextI+size <= firstCharDifferent {
|
|
i = nextI + size
|
|
size, nextI = decodeSize(a.data, i)
|
|
}
|
|
// Difference is inside this entry.
|
|
aStr, _ := decodeString(a.data, i)
|
|
bStr, _ := decodeString(b.data, i)
|
|
if aStr < bStr {
|
|
return -1
|
|
}
|
|
return +1
|
|
}
|
|
|
|
// Copy labels from b on top of whatever was in ls previously, reusing memory or expanding if needed.
|
|
func (ls *Labels) CopyFrom(b Labels) {
|
|
ls.data = b.data // strings are immutable
|
|
}
|
|
|
|
// IsEmpty returns true if ls represents an empty set of labels.
|
|
func (ls Labels) IsEmpty() bool {
|
|
return len(ls.data) == 0
|
|
}
|
|
|
|
// Len returns the number of labels; it is relatively slow.
|
|
func (ls Labels) Len() int {
|
|
count := 0
|
|
for i := 0; i < len(ls.data); {
|
|
var size int
|
|
size, i = decodeSize(ls.data, i)
|
|
i += size
|
|
size, i = decodeSize(ls.data, i)
|
|
i += size
|
|
count++
|
|
}
|
|
return count
|
|
}
|
|
|
|
// Range calls f on each label.
|
|
func (ls Labels) Range(f func(l Label)) {
|
|
for i := 0; i < len(ls.data); {
|
|
var lName, lValue string
|
|
lName, i = decodeString(ls.data, i)
|
|
lValue, i = decodeString(ls.data, i)
|
|
f(Label{Name: lName, Value: lValue})
|
|
}
|
|
}
|
|
|
|
// Validate calls f on each label. If f returns a non-nil error, then it returns that error cancelling the iteration.
|
|
func (ls Labels) Validate(f func(l Label) error) error {
|
|
for i := 0; i < len(ls.data); {
|
|
var lName, lValue string
|
|
lName, i = decodeString(ls.data, i)
|
|
lValue, i = decodeString(ls.data, i)
|
|
err := f(Label{Name: lName, Value: lValue})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// DropMetricName returns Labels with "__name__" removed.
|
|
func (ls Labels) DropMetricName() Labels {
|
|
for i := 0; i < len(ls.data); {
|
|
lName, i2 := decodeString(ls.data, i)
|
|
size, i2 := decodeSize(ls.data, i2)
|
|
i2 += size
|
|
if lName == MetricName {
|
|
if i == 0 { // Make common case fast with no allocations.
|
|
ls.data = ls.data[i2:]
|
|
} else {
|
|
ls.data = ls.data[:i] + ls.data[i2:]
|
|
}
|
|
break
|
|
} else if lName[0] > MetricName[0] { // Stop looking if we've gone past.
|
|
break
|
|
}
|
|
i = i2
|
|
}
|
|
return ls
|
|
}
|
|
|
|
// InternStrings is a no-op because it would only save when the whole set of labels is identical.
|
|
func (ls *Labels) InternStrings(intern func(string) string) {
|
|
}
|
|
|
|
// ReleaseStrings is a no-op for the same reason as InternStrings.
|
|
func (ls Labels) ReleaseStrings(release func(string)) {
|
|
}
|
|
|
|
// Builder allows modifying Labels.
|
|
type Builder struct {
|
|
base Labels
|
|
del []string
|
|
add []Label
|
|
}
|
|
|
|
// Reset clears all current state for the builder.
|
|
func (b *Builder) Reset(base Labels) {
|
|
b.base = base
|
|
b.del = b.del[:0]
|
|
b.add = b.add[:0]
|
|
b.base.Range(func(l Label) {
|
|
if l.Value == "" {
|
|
b.del = append(b.del, l.Name)
|
|
}
|
|
})
|
|
}
|
|
|
|
// Labels returns the labels from the builder.
|
|
// If no modifications were made, the original labels are returned.
|
|
func (b *Builder) Labels() Labels {
|
|
if len(b.del) == 0 && len(b.add) == 0 {
|
|
return b.base
|
|
}
|
|
|
|
slices.SortFunc(b.add, func(a, b Label) int { return strings.Compare(a.Name, b.Name) })
|
|
slices.Sort(b.del)
|
|
a, d := 0, 0
|
|
|
|
bufSize := len(b.base.data) + labelsSize(b.add)
|
|
buf := make([]byte, 0, bufSize)
|
|
for pos := 0; pos < len(b.base.data); {
|
|
oldPos := pos
|
|
var lName string
|
|
lName, pos = decodeString(b.base.data, pos)
|
|
_, pos = decodeString(b.base.data, pos)
|
|
for d < len(b.del) && b.del[d] < lName {
|
|
d++
|
|
}
|
|
if d < len(b.del) && b.del[d] == lName {
|
|
continue // This label has been deleted.
|
|
}
|
|
for ; a < len(b.add) && b.add[a].Name < lName; a++ {
|
|
buf = appendLabelTo(buf, &b.add[a]) // Insert label that was not in the base set.
|
|
}
|
|
if a < len(b.add) && b.add[a].Name == lName {
|
|
buf = appendLabelTo(buf, &b.add[a])
|
|
a++
|
|
continue // This label has been replaced.
|
|
}
|
|
buf = append(buf, b.base.data[oldPos:pos]...)
|
|
}
|
|
// We have come to the end of the base set; add any remaining labels.
|
|
for ; a < len(b.add); a++ {
|
|
buf = appendLabelTo(buf, &b.add[a])
|
|
}
|
|
return Labels{data: yoloString(buf)}
|
|
}
|
|
|
|
func marshalLabelsToSizedBuffer(lbls []Label, data []byte) int {
|
|
i := len(data)
|
|
for index := len(lbls) - 1; index >= 0; index-- {
|
|
size := marshalLabelToSizedBuffer(&lbls[index], data[:i])
|
|
i -= size
|
|
}
|
|
return len(data) - i
|
|
}
|
|
|
|
func marshalLabelToSizedBuffer(m *Label, data []byte) int {
|
|
i := len(data)
|
|
i -= len(m.Value)
|
|
copy(data[i:], m.Value)
|
|
i = encodeSize(data, i, len(m.Value))
|
|
i -= len(m.Name)
|
|
copy(data[i:], m.Name)
|
|
i = encodeSize(data, i, len(m.Name))
|
|
return len(data) - i
|
|
}
|
|
|
|
func sizeVarint(x uint64) (n int) {
|
|
// Most common case first
|
|
if x < 1<<7 {
|
|
return 1
|
|
}
|
|
if x >= 1<<56 {
|
|
return 9
|
|
}
|
|
if x >= 1<<28 {
|
|
x >>= 28
|
|
n = 4
|
|
}
|
|
if x >= 1<<14 {
|
|
x >>= 14
|
|
n += 2
|
|
}
|
|
if x >= 1<<7 {
|
|
n++
|
|
}
|
|
return n + 1
|
|
}
|
|
|
|
func encodeVarint(data []byte, offset int, v uint64) int {
|
|
offset -= sizeVarint(v)
|
|
base := offset
|
|
for v >= 1<<7 {
|
|
data[offset] = uint8(v&0x7f | 0x80)
|
|
v >>= 7
|
|
offset++
|
|
}
|
|
data[offset] = uint8(v)
|
|
return base
|
|
}
|
|
|
|
// Special code for the common case that a size is less than 128
|
|
func encodeSize(data []byte, offset, v int) int {
|
|
if v < 1<<7 {
|
|
offset--
|
|
data[offset] = uint8(v)
|
|
return offset
|
|
}
|
|
return encodeVarint(data, offset, uint64(v))
|
|
}
|
|
|
|
func labelsSize(lbls []Label) (n int) {
|
|
// we just encode name/value/name/value, without any extra tags or length bytes
|
|
for _, e := range lbls {
|
|
n += labelSize(&e)
|
|
}
|
|
return n
|
|
}
|
|
|
|
func labelSize(m *Label) (n int) {
|
|
// strings are encoded as length followed by contents.
|
|
l := len(m.Name)
|
|
n += l + sizeVarint(uint64(l))
|
|
l = len(m.Value)
|
|
n += l + sizeVarint(uint64(l))
|
|
return n
|
|
}
|
|
|
|
func appendLabelTo(buf []byte, m *Label) []byte {
|
|
size := labelSize(m)
|
|
sizeRequired := len(buf) + size
|
|
if cap(buf) >= sizeRequired {
|
|
buf = buf[:sizeRequired]
|
|
} else {
|
|
bufSize := cap(buf)
|
|
// Double size of buffer each time it needs to grow, to amortise copying cost.
|
|
for bufSize < sizeRequired {
|
|
bufSize = bufSize*2 + 1
|
|
}
|
|
newBuf := make([]byte, sizeRequired, bufSize)
|
|
copy(newBuf, buf)
|
|
buf = newBuf
|
|
}
|
|
marshalLabelToSizedBuffer(m, buf)
|
|
return buf
|
|
}
|
|
|
|
// ScratchBuilder allows efficient construction of a Labels from scratch.
|
|
type ScratchBuilder struct {
|
|
add []Label
|
|
output Labels
|
|
overwriteBuffer []byte
|
|
}
|
|
|
|
// NewScratchBuilder creates a ScratchBuilder initialized for Labels with n entries.
|
|
func NewScratchBuilder(n int) ScratchBuilder {
|
|
return ScratchBuilder{add: make([]Label, 0, n)}
|
|
}
|
|
|
|
func (b *ScratchBuilder) Reset() {
|
|
b.add = b.add[:0]
|
|
b.output = EmptyLabels()
|
|
}
|
|
|
|
// Add a name/value pair.
|
|
// Note if you Add the same name twice you will get a duplicate label, which is invalid.
|
|
func (b *ScratchBuilder) Add(name, value string) {
|
|
b.add = append(b.add, Label{Name: name, Value: value})
|
|
}
|
|
|
|
// Add a name/value pair, using []byte instead of string to reduce memory allocations.
|
|
// The values must remain live until Labels() is called.
|
|
func (b *ScratchBuilder) UnsafeAddBytes(name, value []byte) {
|
|
b.add = append(b.add, Label{Name: yoloString(name), Value: yoloString(value)})
|
|
}
|
|
|
|
// Sort the labels added so far by name.
|
|
func (b *ScratchBuilder) Sort() {
|
|
slices.SortFunc(b.add, func(a, b Label) int { return strings.Compare(a.Name, b.Name) })
|
|
}
|
|
|
|
// Assign is for when you already have a Labels which you want this ScratchBuilder to return.
|
|
func (b *ScratchBuilder) Assign(l Labels) {
|
|
b.output = l
|
|
}
|
|
|
|
// Labels returns the name/value pairs added as a Labels object. Calling Add() after Labels() has no effect.
|
|
// Note: if you want them sorted, call Sort() first.
|
|
func (b *ScratchBuilder) Labels() Labels {
|
|
if b.output.IsEmpty() {
|
|
size := labelsSize(b.add)
|
|
buf := make([]byte, size)
|
|
marshalLabelsToSizedBuffer(b.add, buf)
|
|
b.output = Labels{data: yoloString(buf)}
|
|
}
|
|
return b.output
|
|
}
|
|
|
|
// Write the newly-built Labels out to ls, reusing an internal buffer.
|
|
// Callers must ensure that there are no other references to ls, or any strings fetched from it.
|
|
func (b *ScratchBuilder) Overwrite(ls *Labels) {
|
|
size := labelsSize(b.add)
|
|
if size <= cap(b.overwriteBuffer) {
|
|
b.overwriteBuffer = b.overwriteBuffer[:size]
|
|
} else {
|
|
b.overwriteBuffer = make([]byte, size)
|
|
}
|
|
marshalLabelsToSizedBuffer(b.add, b.overwriteBuffer)
|
|
ls.data = yoloString(b.overwriteBuffer)
|
|
}
|
|
|
|
// Symbol-table is no-op, just for api parity with dedupelabels.
|
|
type SymbolTable struct{}
|
|
|
|
func NewSymbolTable() *SymbolTable { return nil }
|
|
|
|
func (t *SymbolTable) Len() int { return 0 }
|
|
|
|
// NewBuilderWithSymbolTable creates a Builder, for api parity with dedupelabels.
|
|
func NewBuilderWithSymbolTable(_ *SymbolTable) *Builder {
|
|
return NewBuilder(EmptyLabels())
|
|
}
|
|
|
|
// NewScratchBuilderWithSymbolTable creates a ScratchBuilder, for api parity with dedupelabels.
|
|
func NewScratchBuilderWithSymbolTable(_ *SymbolTable, n int) ScratchBuilder {
|
|
return NewScratchBuilder(n)
|
|
}
|
|
|
|
func (b *ScratchBuilder) SetSymbolTable(_ *SymbolTable) {
|
|
// no-op
|
|
}
|