diff options
Diffstat (limited to 'src/mongo/gotools/vendor/src/github.com/10gen/openssl/utils/future.go')
-rw-r--r-- | src/mongo/gotools/vendor/src/github.com/10gen/openssl/utils/future.go | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/src/mongo/gotools/vendor/src/github.com/10gen/openssl/utils/future.go b/src/mongo/gotools/vendor/src/github.com/10gen/openssl/utils/future.go new file mode 100644 index 00000000000..fa1bbbfb861 --- /dev/null +++ b/src/mongo/gotools/vendor/src/github.com/10gen/openssl/utils/future.go @@ -0,0 +1,79 @@ +// Copyright (C) 2014 Space Monkey, Inc. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package utils + +import ( + "sync" +) + +// Future is a type that is essentially the inverse of a channel. With a +// channel, you have multiple senders and one receiver. With a future, you can +// have multiple receivers and one sender. Additionally, a future protects +// against double-sends. Since this is usually used for returning function +// results, we also capture and return error values as well. Use NewFuture +// to initialize. +type Future struct { + mutex *sync.Mutex + cond *sync.Cond + received bool + val interface{} + err error +} + +// NewFuture returns an initialized and ready Future. +func NewFuture() *Future { + mutex := &sync.Mutex{} + return &Future{ + mutex: mutex, + cond: sync.NewCond(mutex), + received: false, + val: nil, + err: nil, + } +} + +// Get blocks until the Future has a value set. +func (self *Future) Get() (interface{}, error) { + self.mutex.Lock() + defer self.mutex.Unlock() + for { + if self.received { + return self.val, self.err + } + self.cond.Wait() + } +} + +// Fired returns whether or not a value has been set. If Fired is true, Get +// won't block. +func (self *Future) Fired() bool { + self.mutex.Lock() + defer self.mutex.Unlock() + return self.received +} + +// Set provides the value to present and future Get calls. If Set has already +// been called, this is a no-op. +func (self *Future) Set(val interface{}, err error) { + self.mutex.Lock() + defer self.mutex.Unlock() + if self.received { + return + } + self.received = true + self.val = val + self.err = err + self.cond.Broadcast() +} |