153 lines
3.6 KiB
Go
153 lines
3.6 KiB
Go
/*
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* priority.go
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package main
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import (
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"fmt"
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"github.com/apple/foundationdb/bindings/go/src/fdb"
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"github.com/apple/foundationdb/bindings/go/src/fdb/directory"
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"github.com/apple/foundationdb/bindings/go/src/fdb/subspace"
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"github.com/apple/foundationdb/bindings/go/src/fdb/tuple"
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"log"
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"math/rand"
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)
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func clear_subspace(trtr fdb.Transactor, sub subspace.Subspace) error {
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_, err := trtr.Transact(func(tr fdb.Transaction) (interface{}, error) {
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tr.ClearRange(sub)
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return nil, nil
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})
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return err
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}
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func _pack(t interface{}) []byte {
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return tuple.Tuple{t}.Pack()
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}
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func _unpack(t []byte) tuple.Tuple {
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i, e := tuple.Unpack(t)
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if e != nil {
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return nil
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}
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return i
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}
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type Priority struct {
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PrioritySS subspace.Subspace
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}
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func (prty Priority) Push(trtr fdb.Transactor, value interface{}, priority int) {
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trtr.Transact(func(tr fdb.Transaction) (interface{}, error) {
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tr.Set(prty.PrioritySS.Pack(tuple.Tuple{priority, prty._NextCount(tr, priority), rand.Intn(20)}), _pack(value))
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return nil, nil
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})
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}
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func (prty Priority) _NextCount(trtr fdb.Transactor, priority int) int {
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res, err := trtr.Transact(func(tr fdb.Transaction) (interface{}, error) {
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kr, e := fdb.PrefixRange(prty.PrioritySS.Pack(tuple.Tuple{priority}))
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if e != nil {
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return nil, e
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}
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ks, e := tr.Snapshot().GetRange(kr, fdb.RangeOptions{1, -1, true}).GetSliceWithError()
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if e != nil {
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return nil, e
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}
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if len(ks) == 0 {
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return 0, nil
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}
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k, e := prty.PrioritySS.Unpack(ks[0].Key)
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return k[0].(int) + 1, nil
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})
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if err != nil {
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return 0
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}
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return res.(int)
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}
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func (prty Priority) Pop(trtr fdb.Transactor, max bool) interface{} {
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res, _ := trtr.Transact(func(tr fdb.Transaction) (interface{}, error) {
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ks, err := tr.GetRange(prty.PrioritySS, fdb.RangeOptions{1, -1, max}).GetSliceWithError()
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if err != nil {
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return nil, err
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}
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if len(ks) == 0 {
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return nil, nil
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}
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tr.Clear(ks[0].Key)
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return _unpack(ks[0].Value)[0], nil
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})
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return res
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}
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func (prty Priority) Peek(trtr fdb.Transactor, max bool) interface{} {
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res, _ := trtr.Transact(func(tr fdb.Transaction) (interface{}, error) {
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ks, err := tr.GetRange(prty.PrioritySS, fdb.RangeOptions{1, -1, max}).GetSliceWithError()
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if err != nil {
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return nil, err
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}
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if len(ks) == 0 {
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return nil, nil
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}
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return _unpack(ks[0].Value)[0], nil
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})
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return res
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}
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func main() {
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fdb.MustAPIVersion(700)
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db := fdb.MustOpenDefault()
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PriorityDemoDir, err := directory.CreateOrOpen(db, []string{"Priority"}, nil)
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if err != nil {
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log.Fatal(err)
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}
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clear_subspace(db, PriorityDemoDir)
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var p Priority
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p = Priority{PriorityDemoDir}
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p.Push(db, "Hello World!", 0)
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fmt.Println(p.Pop(db, false))
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p.Push(db, "a", 1)
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p.Push(db, "b", 5)
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p.Push(db, "c", 2)
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p.Push(db, "d", 4)
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p.Push(db, "e", 3)
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fmt.Println(p.Peek(db, false))
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fmt.Println(p.Peek(db, false))
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fmt.Println(p.Pop(db, false))
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fmt.Println(p.Pop(db, false))
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fmt.Println(p.Pop(db, false))
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fmt.Println(p.Pop(db, false))
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fmt.Println(p.Pop(db, false))
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}
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