Initial QSfera import

Server/vendor/github.com/open-policy-agent/opa/v1/ast/varset.go

@@ -0,0 +1,131 @@
+// Copyright 2016 The OPA Authors.  All rights reserved.
+// Use of this source code is governed by an Apache2
+// license that can be found in the LICENSE file.
+
+package ast
+
+import (
+	"fmt"
+	"slices"
+
+	"github.com/open-policy-agent/opa/v1/util"
+)
+
+// VarSet represents a set of variables.
+type VarSet map[Var]struct{ *Location }
+
+// NewVarSet returns a new VarSet containing the specified variables.
+func NewVarSet(vs ...Var) VarSet {
+	s := make(VarSet, len(vs))
+	for _, v := range vs {
+		s.Add(v)
+	}
+	return s
+}
+
+// NewVarSet returns a new VarSet containing the specified variables.
+func NewVarSetOfSize(size int) VarSet {
+	return make(VarSet, size)
+}
+
+// Add updates the set to include the variable "v".
+func (s VarSet) Add(v Var) {
+	if _, ok := s[v]; !ok {
+		s[v] = struct{ *Location }{}
+	}
+}
+
+func (s VarSet) AddLocation(v Var, l *Location) {
+	if entry, ok := s[v]; ok {
+		entry.Location = l
+		s[v] = entry
+	}
+}
+
+// Contains returns true if the set contains the variable "v".
+func (s VarSet) Contains(v Var) bool {
+	_, ok := s[v]
+	return ok
+}
+
+// Copy returns a shallow copy of the VarSet.
+func (s VarSet) Copy() VarSet {
+	cpy := NewVarSetOfSize(len(s))
+	for v := range s {
+		cpy.Add(v)
+	}
+	return cpy
+}
+
+// Diff returns a VarSet containing variables in s that are not in vs.
+func (s VarSet) Diff(vs VarSet) VarSet {
+	r := NewVarSetOfSize(s.DiffCount(vs))
+	for v := range s {
+		if !vs.Contains(v) {
+			r.Add(v)
+			r.AddLocation(v, s[v].Location)
+		}
+	}
+	return r
+}
+
+// DiffCount returns the number of variables in s that are not in vs.
+func (s VarSet) DiffCount(vs VarSet) (i int) {
+	for v := range s {
+		if !vs.Contains(v) {
+			i++
+		}
+	}
+	return
+}
+
+// Equal returns true if s contains exactly the same elements as vs.
+func (s VarSet) Equal(vs VarSet) bool {
+	if len(s) != len(vs) {
+		return false
+	}
+	for v := range s {
+		if !vs.Contains(v) {
+			return false
+		}
+	}
+	return true
+}
+
+// Intersect returns a VarSet containing variables in s that are in vs.
+func (s VarSet) Intersect(vs VarSet) VarSet {
+	i := 0
+	for v := range s {
+		if vs.Contains(v) {
+			i++
+		}
+	}
+	r := NewVarSetOfSize(i)
+	for v := range s {
+		if vs.Contains(v) {
+			r.Add(v)
+		}
+	}
+	return r
+}
+
+// Sorted returns a new sorted slice of vars from s.
+func (s VarSet) Sorted() []Var {
+	sorted := make([]Var, 0, len(s))
+	for v := range s {
+		sorted = append(sorted, v)
+	}
+	slices.SortFunc(sorted, VarCompare)
+	return sorted
+}
+
+// Update merges the other VarSet into this VarSet.
+func (s VarSet) Update(vs VarSet) {
+	for v := range vs {
+		s.Add(v)
+	}
+}
+
+func (s VarSet) String() string {
+	return fmt.Sprintf("%v", util.KeysSorted(s))
+}