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

modules/queue/unique_queue_disk.go

@@ -0,0 +1,104 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package queue
+
+import (
+	"gitea.com/lunny/levelqueue"
+)
+
+// LevelUniqueQueueType is the type for level queue
+const LevelUniqueQueueType Type = "unique-level"
+
+// LevelUniqueQueueConfiguration is the configuration for a LevelUniqueQueue
+type LevelUniqueQueueConfiguration struct {
+	ByteFIFOQueueConfiguration
+	DataDir string
+}
+
+// LevelUniqueQueue implements a disk library queue
+type LevelUniqueQueue struct {
+	*ByteFIFOUniqueQueue
+}
+
+// NewLevelUniqueQueue creates a ledis local queue
+//
+// Please note that this Queue does not guarantee that a particular
+// task cannot be processed twice or more at the same time. Uniqueness is
+// only guaranteed whilst the task is waiting in the queue.
+func NewLevelUniqueQueue(handle HandlerFunc, cfg, exemplar interface{}) (Queue, error) {
+	configInterface, err := toConfig(LevelUniqueQueueConfiguration{}, cfg)
+	if err != nil {
+		return nil, err
+	}
+	config := configInterface.(LevelUniqueQueueConfiguration)
+
+	byteFIFO, err := NewLevelUniqueQueueByteFIFO(config.DataDir)
+	if err != nil {
+		return nil, err
+	}
+
+	byteFIFOQueue, err := NewByteFIFOUniqueQueue(LevelUniqueQueueType, byteFIFO, handle, config.ByteFIFOQueueConfiguration, exemplar)
+	if err != nil {
+		return nil, err
+	}
+
+	queue := &LevelUniqueQueue{
+		ByteFIFOUniqueQueue: byteFIFOQueue,
+	}
+	queue.qid = GetManager().Add(queue, LevelUniqueQueueType, config, exemplar)
+	return queue, nil
+}
+
+var _ (UniqueByteFIFO) = &LevelUniqueQueueByteFIFO{}
+
+// LevelUniqueQueueByteFIFO represents a ByteFIFO formed from a LevelUniqueQueue
+type LevelUniqueQueueByteFIFO struct {
+	internal *levelqueue.UniqueQueue
+}
+
+// NewLevelUniqueQueueByteFIFO creates a new ByteFIFO formed from a LevelUniqueQueue
+func NewLevelUniqueQueueByteFIFO(dataDir string) (*LevelUniqueQueueByteFIFO, error) {
+	internal, err := levelqueue.OpenUnique(dataDir)
+	if err != nil {
+		return nil, err
+	}
+
+	return &LevelUniqueQueueByteFIFO{
+		internal: internal,
+	}, nil
+}
+
+// PushFunc pushes data to the end of the fifo and calls the callback if it is added
+func (fifo *LevelUniqueQueueByteFIFO) PushFunc(data []byte, fn func() error) error {
+	return fifo.internal.LPushFunc(data, fn)
+}
+
+// Pop pops data from the start of the fifo
+func (fifo *LevelUniqueQueueByteFIFO) Pop() ([]byte, error) {
+	data, err := fifo.internal.RPop()
+	if err != nil && err != levelqueue.ErrNotFound {
+		return nil, err
+	}
+	return data, nil
+}
+
+// Len returns the length of the fifo
+func (fifo *LevelUniqueQueueByteFIFO) Len() int64 {
+	return fifo.internal.Len()
+}
+
+// Has returns whether the fifo contains this data
+func (fifo *LevelUniqueQueueByteFIFO) Has(data []byte) (bool, error) {
+	return fifo.internal.Has(data)
+}
+
+// Close this fifo
+func (fifo *LevelUniqueQueueByteFIFO) Close() error {
+	return fifo.internal.Close()
+}
+
+func init() {
+	queuesMap[LevelUniqueQueueType] = NewLevelUniqueQueue
+}