Merge pull request #243 from logicalhan/generics

add generic sets to utils

set/OWNERS

@@ -0,0 +1,8 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+reviewers:
+  - logicalhan
+  - thockin
+approvers:
+  - logicalhan
+  - thockin

set/ordered.go

@@ -0,0 +1,53 @@
+/*
+Copyright 2023 The Kubernetes 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.
+*/
+
+package set
+
+// ordered is a constraint that permits any ordered type: any type
+// that supports the operators < <= >= >.
+// If future releases of Go add new ordered types,
+// this constraint will be modified to include them.
+type ordered interface {
+	integer | float | ~string
+}
+
+// integer is a constraint that permits any integer type.
+// If future releases of Go add new predeclared integer types,
+// this constraint will be modified to include them.
+type integer interface {
+	signed | unsigned
+}
+
+// float is a constraint that permits any floating-point type.
+// If future releases of Go add new predeclared floating-point types,
+// this constraint will be modified to include them.
+type float interface {
+	~float32 | ~float64
+}
+
+// signed is a constraint that permits any signed integer type.
+// If future releases of Go add new predeclared signed integer types,
+// this constraint will be modified to include them.
+type signed interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64
+}
+
+// unsigned is a constraint that permits any unsigned integer type.
+// If future releases of Go add new predeclared unsigned integer types,
+// this constraint will be modified to include them.
+type unsigned interface {
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr
+}

set/set.go

@@ -0,0 +1,229 @@
+/*
+Copyright 2023 The Kubernetes 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.
+*/
+
+package set
+
+import (
+	"sort"
+)
+
+// Empty is public since it is used by some internal API objects for conversions between external
+// string arrays and internal sets, and conversion logic requires public types today.
+type Empty struct{}
+
+// Set is a set of the same type elements, implemented via map[ordered]struct{} for minimal memory consumption.
+type Set[E ordered] map[E]Empty
+
+// New creates a new set.
+func New[E ordered](items ...E) Set[E] {
+	ss := Set[E]{}
+	ss.Insert(items...)
+	return ss
+}
+
+// KeySet creates a Set[E] from a keys of a map[E](? extends interface{}).
+func KeySet[E ordered, A any](theMap map[E]A) Set[E] {
+	ret := Set[E]{}
+	for key := range theMap {
+		ret.Insert(key)
+	}
+	return ret
+}
+
+// Insert adds items to the set.
+func (s Set[E]) Insert(items ...E) Set[E] {
+	for _, item := range items {
+		s[item] = Empty{}
+	}
+	return s
+}
+
+// Delete removes all items from the set.
+func (s Set[E]) Delete(items ...E) Set[E] {
+	for _, item := range items {
+		delete(s, item)
+	}
+	return s
+}
+
+// Has returns true if and only if item is contained in the set.
+func (s Set[E]) Has(item E) bool {
+	_, contained := s[item]
+	return contained
+}
+
+// HasAll returns true if and only if all items are contained in the set.
+func (s Set[E]) HasAll(items ...E) bool {
+	for _, item := range items {
+		if !s.Has(item) {
+			return false
+		}
+	}
+	return true
+}
+
+// HasAny returns true if any items are contained in the set.
+func (s Set[E]) HasAny(items ...E) bool {
+	for _, item := range items {
+		if s.Has(item) {
+			return true
+		}
+	}
+	return false
+}
+
+// Union returns a new set which includes items in either s1 or s2.
+// For example:
+// s1 = {a1, a2}
+// s2 = {a3, a4}
+// s1.Union(s2) = {a1, a2, a3, a4}
+// s2.Union(s1) = {a1, a2, a3, a4}
+func (s Set[E]) Union(s2 Set[E]) Set[E] {
+	result := Set[E]{}
+	result.Insert(s.UnsortedList()...)
+	result.Insert(s2.UnsortedList()...)
+	return result
+}
+
+// Len returns the number of elements in the set.
+func (s Set[E]) Len() int {
+	return len(s)
+}
+
+// Intersection returns a new set which includes the item in BOTH s1 and s2
+// For example:
+// s1 = {a1, a2}
+// s2 = {a2, a3}
+// s1.Intersection(s2) = {a2}
+func (s Set[E]) Intersection(s2 Set[E]) Set[E] {
+	var walk, other Set[E]
+	result := Set[E]{}
+	if s.Len() < s2.Len() {
+		walk = s
+		other = s2
+	} else {
+		walk = s2
+		other = s
+	}
+	for key := range walk {
+		if other.Has(key) {
+			result.Insert(key)
+		}
+	}
+	return result
+}
+
+// IsSuperset returns true if and only if s1 is a superset of s2.
+func (s Set[E]) IsSuperset(s2 Set[E]) bool {
+	for item := range s2 {
+		if !s.Has(item) {
+			return false
+		}
+	}
+	return true
+}
+
+// Difference returns a set of objects that are not in s2
+// For example:
+// s1 = {a1, a2, a3}
+// s2 = {a1, a2, a4, a5}
+// s1.Difference(s2) = {a3}
+// s2.Difference(s1) = {a4, a5}
+func (s Set[E]) Difference(s2 Set[E]) Set[E] {
+	result := Set[E]{}
+	for key := range s {
+		if !s2.Has(key) {
+			result.Insert(key)
+		}
+	}
+	return result
+}
+
+// Equal returns true if and only if s1 is equal (as a set) to s2.
+// Two sets are equal if their membership is identical.
+func (s Set[E]) Equal(s2 Set[E]) bool {
+	return s.Len() == s.Len() && s.IsSuperset(s2)
+}
+
+type sortableSlice[E ordered] []E
+
+func (s sortableSlice[E]) Len() int {
+	return len(s)
+}
+func (s sortableSlice[E]) Less(i, j int) bool { return s[i] < s[j] }
+func (s sortableSlice[E]) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+
+// SortedList returns the contents as a sorted slice.
+func (s Set[E]) SortedList() []E {
+	res := make(sortableSlice[E], 0, s.Len())
+	for key := range s {
+		res = append(res, key)
+	}
+	sort.Sort(res)
+	return res
+}
+
+// UnsortedList returns the slice with contents in random order.
+func (s Set[E]) UnsortedList() []E {
+	res := make([]E, 0, len(s))
+	for key := range s {
+		res = append(res, key)
+	}
+	return res
+}
+
+// PopAny returns a single element from the set.
+func (s Set[E]) PopAny() (E, bool) {
+	for key := range s {
+		s.Delete(key)
+		return key, true
+	}
+	var zeroValue E
+	return zeroValue, false
+}
+
+// Clone returns a new set which is a copy of the current set.
+func (s Set[T]) Clone() Set[T] {
+	result := make(Set[T], len(s))
+	for key := range s {
+		result.Insert(key)
+	}
+	return result
+}
+
+// SymmetricDifference returns a set of elements which are in either of the sets, but not in their intersection.
+// For example:
+// s1 = {a1, a2, a3}
+// s2 = {a1, a2, a4, a5}
+// s1.SymmetricDifference(s2) = {a3, a4, a5}
+// s2.SymmetricDifference(s1) = {a3, a4, a5}
+func (s Set[T]) SymmetricDifference(s2 Set[T]) Set[T] {
+	return s.Difference(s2).Union(s2.Difference(s))
+}
+
+// Clear empties the set.
+// It is preferable to replace the set with a newly constructed set,
+// but not all callers can do that (when there are other references to the map).
+// In some cases the set *won't* be fully cleared, e.g. a Set[float32] containing NaN
+// can't be cleared because NaN can't be removed.
+// For sets containing items of a type that is reflexive for ==,
+// this is optimized to a single call to runtime.mapclear().
+func (s Set[T]) Clear() Set[T] {
+	for key := range s {
+		delete(s, key)
+	}
+	return s
+}