2c903383b5
* 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
111 lines
2.7 KiB
Go
111 lines
2.7 KiB
Go
// Copyright 2020 Andrew Thornton. All rights reserved.
|
|
// Use of this source code is governed by a MIT-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package levelqueue
|
|
|
|
import (
|
|
"sync"
|
|
|
|
"github.com/syndtr/goleveldb/leveldb"
|
|
"github.com/syndtr/goleveldb/leveldb/util"
|
|
)
|
|
|
|
const (
|
|
setPrefixStr = "set"
|
|
)
|
|
|
|
// Set defines a set struct
|
|
type Set struct {
|
|
db *leveldb.DB
|
|
closeUnderlyingDB bool
|
|
lock sync.Mutex
|
|
prefix []byte
|
|
}
|
|
|
|
// OpenSet opens a set from the db path or creates a set if it doesn't exist.
|
|
// The keys will be prefixed with "set-" by default
|
|
func OpenSet(dataDir string) (*Set, error) {
|
|
db, err := leveldb.OpenFile(dataDir, nil)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return NewSet(db, []byte(setPrefixStr), true)
|
|
}
|
|
|
|
// NewSet creates a set from a db. The keys will be prefixed with prefix
|
|
// and at close the db will be closed as per closeUnderlyingDB
|
|
func NewSet(db *leveldb.DB, prefix []byte, closeUnderlyingDB bool) (*Set, error) {
|
|
set := &Set{
|
|
db: db,
|
|
closeUnderlyingDB: closeUnderlyingDB,
|
|
}
|
|
set.prefix = make([]byte, len(prefix))
|
|
copy(set.prefix, prefix)
|
|
|
|
return set, nil
|
|
}
|
|
|
|
// Add adds a member string to a key set, returns true if the member was not already present
|
|
func (set *Set) Add(value []byte) (bool, error) {
|
|
set.lock.Lock()
|
|
defer set.lock.Unlock()
|
|
setKey := withPrefix(set.prefix, value)
|
|
has, err := set.db.Has(setKey, nil)
|
|
if err != nil || has {
|
|
return !has, err
|
|
}
|
|
return !has, set.db.Put(setKey, []byte(""), nil)
|
|
}
|
|
|
|
// Members returns the current members of the set
|
|
func (set *Set) Members() ([][]byte, error) {
|
|
set.lock.Lock()
|
|
defer set.lock.Unlock()
|
|
var members [][]byte
|
|
prefix := withPrefix(set.prefix, []byte{})
|
|
iter := set.db.NewIterator(util.BytesPrefix(prefix), nil)
|
|
for iter.Next() {
|
|
slice := iter.Key()[len(prefix):]
|
|
value := make([]byte, len(slice))
|
|
copy(value, slice)
|
|
members = append(members, value)
|
|
}
|
|
iter.Release()
|
|
return members, iter.Error()
|
|
}
|
|
|
|
// Has returns if the member is in the set
|
|
func (set *Set) Has(value []byte) (bool, error) {
|
|
set.lock.Lock()
|
|
defer set.lock.Unlock()
|
|
setKey := withPrefix(set.prefix, value)
|
|
|
|
return set.db.Has(setKey, nil)
|
|
}
|
|
|
|
// Remove removes a member from the set, returns true if the member was present
|
|
func (set *Set) Remove(value []byte) (bool, error) {
|
|
set.lock.Lock()
|
|
defer set.lock.Unlock()
|
|
setKey := withPrefix(set.prefix, value)
|
|
|
|
has, err := set.db.Has(setKey, nil)
|
|
if err != nil || !has {
|
|
return has, err
|
|
}
|
|
|
|
return has, set.db.Delete(setKey, nil)
|
|
}
|
|
|
|
// Close closes the set (and the underlying db if set to closeUnderlyingDB)
|
|
func (set *Set) Close() error {
|
|
if !set.closeUnderlyingDB {
|
|
set.db = nil
|
|
return nil
|
|
}
|
|
err := set.db.Close()
|
|
set.db = nil
|
|
return err
|
|
}
|