Initial QSfera import

Server/vendor/go.opentelemetry.io/otel/attribute/internal/attribute.go

@@ -0,0 +1,75 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+/*
+Package attribute provide several helper functions for some commonly used
+logic of processing attributes.
+*/
+package attribute // import "go.opentelemetry.io/otel/attribute/internal"
+
+import (
+	"reflect"
+)
+
+// sliceElem is the exact set of element types stored in attribute slice values.
+// Using a closed set prevents accidental instantiations for unsupported types.
+type sliceElem interface {
+	bool | int64 | float64 | string
+}
+
+// SliceValue converts a slice into an array with the same elements.
+func SliceValue[T sliceElem](v []T) any {
+	// Keep only the common tiny-slice cases out of reflection. Extending this
+	// much further increases code size for diminishing benefit while larger
+	// slices still need the generic reflective path to preserve comparability.
+	// This matches the short lengths that show up most often in local
+	// benchmarks and semantic convention examples while leaving larger, less
+	// predictable slices on the generic reflective path.
+	switch len(v) {
+	case 0:
+		return [0]T{}
+	case 1:
+		return [1]T{v[0]}
+	case 2:
+		return [2]T{v[0], v[1]}
+	case 3:
+		return [3]T{v[0], v[1], v[2]}
+	}
+
+	return sliceValueReflect(v)
+}
+
+// AsSlice converts an array into a slice with the same elements.
+func AsSlice[T sliceElem](v any) []T {
+	// Mirror the small fixed-array fast path used by SliceValue.
+	switch a := v.(type) {
+	case [0]T:
+		return []T{}
+	case [1]T:
+		return []T{a[0]}
+	case [2]T:
+		return []T{a[0], a[1]}
+	case [3]T:
+		return []T{a[0], a[1], a[2]}
+	}
+
+	return asSliceReflect[T](v)
+}
+
+func sliceValueReflect[T sliceElem](v []T) any {
+	cp := reflect.New(reflect.ArrayOf(len(v), reflect.TypeFor[T]())).Elem()
+	reflect.Copy(cp, reflect.ValueOf(v))
+	return cp.Interface()
+}
+
+func asSliceReflect[T sliceElem](v any) []T {
+	rv := reflect.ValueOf(v)
+	if !rv.IsValid() || rv.Kind() != reflect.Array || rv.Type().Elem() != reflect.TypeFor[T]() {
+		return nil
+	}
+	cpy := make([]T, rv.Len())
+	if len(cpy) > 0 {
+		_ = reflect.Copy(reflect.ValueOf(cpy), rv)
+	}
+	return cpy
+}

Server/vendor/go.opentelemetry.io/otel/attribute/internal/xxhash/xxhash.go

@@ -0,0 +1,64 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package xxhash provides a wrapper around the xxhash library for attribute hashing.
+package xxhash // import "go.opentelemetry.io/otel/attribute/internal/xxhash"
+
+import (
+	"encoding/binary"
+	"math"
+
+	"github.com/cespare/xxhash/v2"
+)
+
+// Hash wraps xxhash.Digest to provide an API friendly for hashing attribute values.
+type Hash struct {
+	d *xxhash.Digest
+}
+
+// New returns a new initialized xxHash64 hasher.
+func New() Hash {
+	return Hash{d: xxhash.New()}
+}
+
+func (h Hash) Uint64(val uint64) Hash {
+	var buf [8]byte
+	binary.LittleEndian.PutUint64(buf[:], val)
+	// errors from Write are always nil for xxhash
+	// if it returns an err then panic
+	_, err := h.d.Write(buf[:])
+	if err != nil {
+		panic("xxhash write of uint64 failed: " + err.Error())
+	}
+	return h
+}
+
+func (h Hash) Bool(val bool) Hash { // nolint:revive // This is a hashing function.
+	if val {
+		return h.Uint64(1)
+	}
+	return h.Uint64(0)
+}
+
+func (h Hash) Float64(val float64) Hash {
+	return h.Uint64(math.Float64bits(val))
+}
+
+func (h Hash) Int64(val int64) Hash {
+	return h.Uint64(uint64(val)) // nolint:gosec // Overflow doesn't matter since we are hashing.
+}
+
+func (h Hash) String(val string) Hash {
+	// errors from WriteString are always nil for xxhash
+	// if it returns an err then panic
+	_, err := h.d.WriteString(val)
+	if err != nil {
+		panic("xxhash write of string failed: " + err.Error())
+	}
+	return h
+}
+
+// Sum64 returns the current hash value.
+func (h Hash) Sum64() uint64 {
+	return h.d.Sum64()
+}