1 files changed, 147 insertions, 0 deletions

diff --git a/cli/internal/util/set.go b/cli/internal/util/set.go
new file mode 100644
index 0000000..b6c5f86
--- /dev/null
+++ b/cli/internal/util/set.go
@@ -0,0 +1,147 @@
+package util
+
+// Set is a set data structure.
+type Set map[interface{}]interface{}
+
+// SetFromStrings creates a Set containing the strings from the given slice
+func SetFromStrings(sl []string) Set {
+	set := make(Set, len(sl))
+	for _, item := range sl {
+		set.Add(item)
+	}
+	return set
+}
+
+// Hashable is the interface used by set to get the hash code of a value.
+// If this isn't given, then the value of the item being added to the set
+// itself is used as the comparison value.
+type Hashable interface {
+	Hashcode() interface{}
+}
+
+// hashcode returns the hashcode used for set elements.
+func hashcode(v interface{}) interface{} {
+	if h, ok := v.(Hashable); ok {
+		return h.Hashcode()
+	}
+
+	return v
+}
+
+// Add adds an item to the set
+func (s Set) Add(v interface{}) {
+	s[hashcode(v)] = v
+}
+
+// Delete removes an item from the set.
+func (s Set) Delete(v interface{}) {
+	delete(s, hashcode(v))
+}
+
+// Includes returns true/false of whether a value is in the set.
+func (s Set) Includes(v interface{}) bool {
+	_, ok := s[hashcode(v)]
+	return ok
+}
+
+// Intersection computes the set intersection with other.
+func (s Set) Intersection(other Set) Set {
+	result := make(Set)
+	if s == nil || other == nil {
+		return result
+	}
+	// Iteration over a smaller set has better performance.
+	if other.Len() < s.Len() {
+		s, other = other, s
+	}
+	for _, v := range s {
+		if other.Includes(v) {
+			result.Add(v)
+		}
+	}
+	return result
+}
+
+// Difference returns a set with the elements that s has but
+// other doesn't.
+func (s Set) Difference(other Set) Set {
+	result := make(Set)
+	for k, v := range s {
+		var ok bool
+		if other != nil {
+			_, ok = other[k]
+		}
+		if !ok {
+			result.Add(v)
+		}
+	}
+
+	return result
+}
+
+// Some tests whether at least one element in the array passes the test implemented by the provided function.
+// It returns a Boolean value.
+func (s Set) Some(cb func(interface{}) bool) bool {
+	for _, v := range s {
+		if cb(v) {
+			return true
+		}
+	}
+	return false
+}
+
+// Filter returns a set that contains the elements from the receiver
+// where the given callback returns true.
+func (s Set) Filter(cb func(interface{}) bool) Set {
+	result := make(Set)
+
+	for _, v := range s {
+		if cb(v) {
+			result.Add(v)
+		}
+	}
+
+	return result
+}
+
+// Len is the number of items in the set.
+func (s Set) Len() int {
+	return len(s)
+}
+
+// List returns the list of set elements.
+func (s Set) List() []interface{} {
+	if s == nil {
+		return nil
+	}
+
+	r := make([]interface{}, 0, len(s))
+	for _, v := range s {
+		r = append(r, v)
+	}
+
+	return r
+}
+
+// UnsafeListOfStrings dangerously casts list to a string
+func (s Set) UnsafeListOfStrings() []string {
+	if s == nil {
+		return nil
+	}
+
+	r := make([]string, 0, len(s))
+	for _, v := range s {
+		r = append(r, v.(string))
+	}
+
+	return r
+}
+
+// Copy returns a shallow copy of the set.
+func (s Set) Copy() Set {
+	c := make(Set)
+	for k, v := range s {
+		c[k] = v
+	}
+	return c
+}