diff --git a/stress_test.go b/stress_test.go index 83d3e85..9d1b1db 100644 --- a/stress_test.go +++ b/stress_test.go @@ -120,3 +120,18 @@ func TestStressBool(t *testing.T) { }() } } + +func TestStressString(t *testing.T) { + defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(_parallelism)) + atom := NewString("") + for i := 0; i < _parallelism; i++ { + go func() { + for j := 0; j < _iterations; j++ { + atom.Load() + atom.Store("abc") + atom.Load() + atom.Store("def") + } + }() + } +} diff --git a/string.go b/string.go new file mode 100644 index 0000000..17eb42e --- /dev/null +++ b/string.go @@ -0,0 +1,47 @@ +// Copyright (c) 2016 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 atomic + +import "sync/atomic" + +// String is an atomic type-safe wrapper around atomic.Value for strings. +type String struct{ atomic.Value } + +// NewString creates a String. +func NewString(s string) *String { + return &String{} +} + +// Load atomically loads the wrapped string. +func (s *String) Load() string { + v := s.Value.Load() + if v == nil { + return "" + } + return v.(string) +} + +// Store atomically stores the passed string. +// Note: Converting the string to an interface{} to store in the atomic.Value +// requires an allocation. +func (s *String) Store(str string) { + s.Value.Store(str) +} diff --git a/string_test.go b/string_test.go new file mode 100644 index 0000000..1c4ab8b --- /dev/null +++ b/string_test.go @@ -0,0 +1,43 @@ +// Copyright (c) 2016 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 atomic + +import ( + "testing" + + "github.com/stretchr/testify/require" +) + +func TestStringNoInitialValue(t *testing.T) { + atom := &String{} + require.Equal(t, "", atom.Load(), "Initial value should be blank string") +} + +func TestString(t *testing.T) { + atom := NewString("") + require.Equal(t, "", atom.Load(), "Expected Load to return initialized value") + + atom.Store("abc") + require.Equal(t, "abc", atom.Load(), "Unexpected value after Store") + + atom = NewString("bcd") + require.Equal(t, "", atom.Load(), "Expected Load to return initialized value") +}