syncset: concurrent set (#253)

* syncset

* use read-lock in empty and count

common/set/bench_test.go

@@ -37,7 +37,7 @@ func BenchmarkSetInsert(b *testing.B) {
 			keys = append(keys, uuid.New().String())
 		}
 
-		for _, set := range []string{"SliceSet", "SortedSet", "MapSet"} {
+		for _, set := range []string{"SliceSet", "SortedSet", "MapSet", "SyncSet"} {
 
 			s := newTestSet(set, n)
 
@@ -62,7 +62,7 @@ func BenchmarkSetContains(b *testing.B) {
 			keys = append(keys, uuid.New().String())
 		}
 
-		for _, set := range []string{"SliceSet", "SortedSet", "MapSet"} {
+		for _, set := range []string{"SliceSet", "SortedSet", "MapSet", "SyncSet"} {
 
 			s := newTestSet(set, n)
 

common/set/set.go

@@ -64,3 +64,10 @@ func New(cap int) Set {
 		return NewSliceSet(cap)
 	}
 }
+
+// NewConcurrent initializes a new concurrent set, picking the appropriate underlying
+// implementation based on the specified expected capacity
+func NewConcurrent(cap int) Set {
+
+	return NewSyncSet(New(cap))
+}

common/set/set_test.go

@@ -36,6 +36,8 @@ func newTestSet(setType string, cap int) (s Set) {
 		s = NewSortedSet(0)
 	case "MapSet":
 		s = NewMapSet(0)
+	case "SyncSet":
+		s = NewSyncSet(New(0))
 	}
 
 	return s
@@ -55,6 +57,8 @@ func TestSet(t *testing.T) {
 		{"MapSet", "SliceSet"},
 		{"MapSet", "SortedSet"},
 		{"MapSet", "MapSet"},
+		{"SyncSet", "SyncSet"},
+		{"SyncSet", "MapSet"},
 	}
 
 	for _, tc := range testCases {

common/set/syncset.go

@@ -0,0 +1,153 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package set
+
+import "sync"
+
+type syncset struct {
+	sync.RWMutex
+	set Set
+}
+
+// NewSyncSet initializes a map-based set
+func NewSyncSet(set Set) Set {
+
+	return &syncset{
+		set: set,
+	}
+}
+
+// Clear clears the set
+func (t *syncset) Clear() {
+
+	t.Lock()
+	t.set.Clear()
+	t.Unlock()
+}
+
+// Empty checks if the set is empty
+func (t *syncset) Empty() bool {
+
+	t.RLock()
+	defer t.RUnlock()
+
+	return t.set.Empty()
+}
+
+// Count returns the size of the set
+func (t *syncset) Count() int {
+
+	t.RLock()
+	defer t.RUnlock()
+
+	return t.set.Count()
+}
+
+// Insert adds a key to the set
+func (t *syncset) Insert(key string) {
+
+	t.Lock()
+	t.set.Insert(key)
+	t.Unlock()
+}
+
+// Contains checks if the key exists in the set
+func (t *syncset) Contains(key string) bool {
+
+	t.RLock()
+	defer t.RUnlock()
+
+	return t.set.Contains(key)
+}
+
+// Remove removes the key from the set
+func (t *syncset) Remove(key string) {
+
+	t.Lock()
+	t.set.Remove(key)
+	t.Unlock()
+}
+
+// Keys returns the set of keys
+func (t *syncset) Keys() []string {
+
+	t.RLock()
+	defer t.RUnlock()
+
+	return t.set.Keys()
+}
+
+// Equals compares the set against another set
+func (t *syncset) Equals(s Set) bool {
+
+	t.RLock()
+	defer t.RUnlock()
+
+	if s.Count() != t.set.Count() {
+		return false
+	}
+
+	for _, k := range s.Keys() {
+		if !t.set.Contains(k) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Subset checks if this set is a subset of another
+func (t *syncset) Subset(s Set) bool {
+
+	t.RLock()
+	defer t.RUnlock()
+
+	if s.Count() < t.set.Count() {
+		return false
+	}
+
+	for _, k := range t.set.Keys() {
+		if !s.Contains(k) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Superset checks if this set is a superset of another
+func (t *syncset) Superset(s Set) bool {
+
+	t.RLock()
+	defer t.RUnlock()
+
+	if s.Count() > t.set.Count() {
+		return false
+	}
+
+	for _, k := range s.Keys() {
+		if !t.set.Contains(k) {
+			return false
+		}
+	}
+
+	return true
+}