639f86915b
This is a basic implementation of a first-in-first-out queue with unbounded size. It's useful for cases where a channel with fixed size might deadlock. The caller is responsible for locking.
118 lines
2.7 KiB
Go
118 lines
2.7 KiB
Go
/*
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Copyright 2024 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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 queue
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import (
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"testing"
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"github.com/stretchr/testify/require"
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)
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func verifyPop(t *testing.T, expectedValue int, expectedOk bool, queue *FIFO[int]) {
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t.Helper()
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actual, ok := queue.Pop()
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require.Equal(t, expectedOk, ok)
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require.Equal(t, expectedValue, actual)
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}
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func verifyEmpty(t *testing.T, queue *FIFO[int]) {
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t.Helper()
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require.Equal(t, 0, queue.Len())
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verifyPop(t, 0, false, queue)
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}
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func TestNull(t *testing.T) {
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var queue FIFO[int]
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verifyEmpty(t, &queue)
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}
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func TestOnePushPop(t *testing.T) {
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var queue FIFO[int]
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expected := 10
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queue.Push(10)
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require.Equal(t, 1, queue.Len())
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verifyPop(t, expected, true, &queue)
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verifyEmpty(t, &queue)
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}
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// Pushes some elements, pops all of them, then the same again.
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func TestWrapAroundEmpty(t *testing.T) {
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var queue FIFO[int]
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for i := 0; i < 5; i++ {
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queue.Push(i)
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}
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require.Equal(t, 5, queue.Len())
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for i := 0; i < 5; i++ {
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verifyPop(t, i, true, &queue)
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}
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verifyEmpty(t, &queue)
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for i := 5; i < 10; i++ {
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queue.Push(i)
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}
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for i := 5; i < 10; i++ {
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verifyPop(t, i, true, &queue)
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}
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verifyEmpty(t, &queue)
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}
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// Pushes some elements, pops one, adds more, then pops all.
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func TestWrapAroundPartial(t *testing.T) {
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var queue FIFO[int]
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for i := 0; i < 5; i++ {
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queue.Push(i)
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}
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require.Equal(t, 5, queue.Len())
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verifyPop(t, 0, true, &queue)
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for i := 5; i < 10; i++ {
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queue.Push(i)
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}
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for i := 1; i < 10; i++ {
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verifyPop(t, i, true, &queue)
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}
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verifyEmpty(t, &queue)
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}
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// Push an unusual amount of elements, pop all, and verify that
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// the FIFO shrinks back again.
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func TestShrink(t *testing.T) {
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var queue FIFO[int]
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for i := 0; i < normalSize*2; i++ {
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queue.Push(i)
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}
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require.Equal(t, normalSize*2, queue.Len())
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require.LessOrEqual(t, 2*normalSize, len(queue.elements))
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// Pop all, should be shrunken when done.
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for i := 0; i < normalSize*2; i++ {
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verifyPop(t, i, true, &queue)
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}
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require.Equal(t, 0, queue.Len())
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require.Equal(t, normalSize, len(queue.elements))
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// Still usable after shrinking?
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queue.Push(42)
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verifyPop(t, 42, true, &queue)
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require.Equal(t, 0, queue.Len())
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require.Equal(t, normalSize, len(queue.elements))
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}
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