githaven-fork/vendor/gitea.com/lunny/levelqueue/README.md
zeripath 2c903383b5
Add Unique Queue infrastructure and move TestPullRequests to this (#9856)
* Upgrade levelqueue to version 0.2.0

This adds functionality for Unique Queues

* Add UniqueQueue interface and functions to create them

* Add UniqueQueue implementations

* Move TestPullRequests over to use UniqueQueue

* Reduce code duplication

* Add bytefifos

* Ensure invalid types are logged

* Fix close race in PersistableChannelQueue Shutdown
2020-02-02 23:19:58 +00:00

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Markdown

# levelqueue
Level queue is a simple queue golang library base on go-leveldb.
[![Build Status](https://drone.gitea.com/api/badges/lunny/levelqueue/status.svg)](https://drone.gitea.com/lunny/levelqueue) [![](http://gocover.io/_badge/gitea.com/lunny/levelqueue)](http://gocover.io/gitea.com/lunny/levelqueue)
[![](https://goreportcard.com/badge/gitea.com/lunny/levelqueue)](https://goreportcard.com/report/gitea.com/lunny/levelqueue)
## Installation
```
go get gitea.com/lunny/levelqueue
```
## Usage
```Go
queue, err := levelqueue.Open("./queue")
err = queue.RPush([]byte("test"))
// pop an element from left of the queue
data, err = queue.LPop()
// if handle success, element will be pop, otherwise it will be keep
queue.LHandle(func(dt []byte) error{
return nil
})
```
You can now create a Set from a leveldb:
```Go
set, err := levelqueue.OpenSet("./set")
added, err:= set.Add([]byte("member1"))
has, err := set.Has([]byte("member1"))
members, err := set.Members()
removed, err := set.Remove([]byte("member1"))
```
And you can create a UniqueQueue from a leveldb:
```Go
queue, err := levelqueue.OpenUnique("./queue")
err := queue.RPush([]byte("member1"))
err = queue.LPush([]byte("member1"))
// Will return ErrAlreadyInQueue
// and so on.
```
## Creating Queues, UniqueQueues and Sets from already open DB
If you have an already open DB you can create these from this using the
`NewQueue`, `NewUniqueQueue` and `NewSet` functions.