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|
package handlers
import (
"context"
"fmt"
"strconv"
"strings"
)
type sessionGenerationKey struct{}
const generationOutputPrefix = "\x1egen:"
func withSessionGeneration(ctx context.Context, generation uint64) context.Context {
if ctx == nil || generation == 0 {
return ctx
}
return context.WithValue(ctx, sessionGenerationKey{}, generation)
}
func sessionGenerationFromContext(ctx context.Context) uint64 {
if ctx == nil {
return 0
}
generation, _ := ctx.Value(sessionGenerationKey{}).(uint64)
return generation
}
func encodeGeneratedMessage(generation uint64, message string) string {
if generation == 0 {
return message
}
return fmt.Sprintf("%s%d\x1e%s", generationOutputPrefix, generation, message)
}
func decodeGeneratedMessage(message string) (uint64, string) {
if !strings.HasPrefix(message, generationOutputPrefix) {
return 0, message
}
rest := strings.TrimPrefix(message, generationOutputPrefix)
parts := strings.SplitN(rest, "\x1e", 2)
if len(parts) != 2 {
return 0, message
}
generation, err := strconv.ParseUint(parts[0], 10, 64)
if err != nil {
return 0, message
}
return generation, parts[1]
}
func encodeGeneratedBytes(generation uint64, payload []byte) []byte {
if generation == 0 {
return payload
}
prefix := []byte(fmt.Sprintf("%s%d\x1e", generationOutputPrefix, generation))
data := make([]byte, 0, len(prefix)+len(payload))
data = append(data, prefix...)
data = append(data, payload...)
return data
}
func decodeGeneratedBytes(payload []byte) (uint64, []byte) {
message := string(payload)
generation, decoded := decodeGeneratedMessage(message)
if generation == 0 {
return 0, payload
}
return generation, []byte(decoded)
}
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