vendor: update buildkit to master@31c870e82a48

Signed-off-by: Justin Chadwell <me@jedevc.com>

vendor/github.com/in-toto/in-toto-golang/in_toto/util.go

@@ -0,0 +1,147 @@
+package in_toto
+
+import (
+	"fmt"
+)
+
+/*
+Set represents a data structure for set operations. See `NewSet` for how to
+create a Set, and available Set receivers for useful set operations.
+
+Under the hood Set aliases map[string]struct{}, where the map keys are the set
+elements and the map values are a memory-efficient way of storing the keys.
+*/
+type Set map[string]struct{}
+
+/*
+NewSet creates a new Set, assigns it the optionally passed variadic string
+elements, and returns it.
+*/
+func NewSet(elems ...string) Set {
+	var s Set = make(map[string]struct{})
+	for _, elem := range elems {
+		s.Add(elem)
+	}
+	return s
+}
+
+/*
+Has returns True if the passed string is member of the set on which it was
+called and False otherwise.
+*/
+func (s Set) Has(elem string) bool {
+	_, ok := s[elem]
+	return ok
+}
+
+/*
+Add adds the passed string to the set on which it was called, if the string is
+not a member of the set.
+*/
+func (s Set) Add(elem string) {
+	s[elem] = struct{}{}
+}
+
+/*
+Remove removes the passed string from the set on which was is called, if the
+string is a member of the set.
+*/
+func (s Set) Remove(elem string) {
+	delete(s, elem)
+}
+
+/*
+Intersection creates and returns a new Set with the elements of the set on
+which it was called that are also in the passed set.
+*/
+func (s Set) Intersection(s2 Set) Set {
+	res := NewSet()
+	for elem := range s {
+		if !s2.Has(elem) {
+			continue
+		}
+		res.Add(elem)
+	}
+	return res
+}
+
+/*
+Difference creates and returns a new Set with the elements of the set on
+which it was called that are not in the passed set.
+*/
+func (s Set) Difference(s2 Set) Set {
+	res := NewSet()
+	for elem := range s {
+		if s2.Has(elem) {
+			continue
+		}
+		res.Add(elem)
+	}
+	return res
+}
+
+/*
+Filter creates and returns a new Set with the elements of the set on which it
+was called that match the passed pattern. A matching error is treated like a
+non-match plus a warning is printed.
+*/
+func (s Set) Filter(pattern string) Set {
+	res := NewSet()
+	for elem := range s {
+		matched, err := match(pattern, elem)
+		if err != nil {
+			fmt.Printf("WARNING: %s, pattern was '%s'\n", err, pattern)
+			continue
+		}
+		if !matched {
+			continue
+		}
+		res.Add(elem)
+	}
+	return res
+}
+
+/*
+Slice creates and returns an unordered string slice with the elements of the
+set on which it was called.
+*/
+func (s Set) Slice() []string {
+	var res []string
+	res = make([]string, 0, len(s))
+	for elem := range s {
+		res = append(res, elem)
+	}
+	return res
+}
+
+/*
+InterfaceKeyStrings returns string keys of passed interface{} map in an
+unordered string slice.
+*/
+func InterfaceKeyStrings(m map[string]interface{}) []string {
+	res := make([]string, len(m))
+	i := 0
+	for k := range m {
+		res[i] = k
+		i++
+	}
+	return res
+}
+
+/*
+IsSubSet checks if the parameter subset is a
+subset of the superset s.
+*/
+func (s Set) IsSubSet(subset Set) bool {
+	if len(subset) > len(s) {
+		return false
+	}
+	for key := range subset {
+		if s.Has(key) {
+			continue
+		} else {
+			return false
+		}
+	}
+	return true
+}