mirror of
https://github.com/gohugoio/hugo.git
synced 2024-11-29 19:02:07 -05:00
Fix data races in sorting and Reverse
The custom sort functions used from the templates had some subtle data race- and related issues, especially when used in the single page template. This commit fixes this by making copies and protect the read and writes with a RWMutex. The results are cached (it will typically be invoked *number of pages* times with exactly the same data). This is, not surprisingly, also faster: ``` benchmark old ns/op new ns/op delta BenchmarkSortByWeightAndReverse 14228 491 -96.55% benchmark old allocs new allocs delta BenchmarkSortByWeightAndReverse 1 0 -100.00% benchmark old bytes new bytes delta BenchmarkSortByWeightAndReverse 32 0 -100.00% ``` Fixes #1293
This commit is contained in:
Bjørn Erik Pedersen
parent
ea6ae769dc
commit
a9c5133a77
4 changed files with 255 additions and 21 deletions
108
hugolib/pageCache.go
Normal file
108
hugolib/pageCache.go
Normal file
|
|
@ -0,0 +1,108 @@
|
|||
// Copyright © 2015 Steve Francia <spf@spf13.com>.
|
||||
//
|
||||
// Licensed under the Simple Public License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
// http://opensource.org/licenses/Simple-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
package hugolib
|
||||
|
||||
import (
|
||||
"sync"
|
||||
)
|
||||
|
||||
type pageCache struct {
|
||||
sync.RWMutex
|
||||
m map[string][][2]Pages
|
||||
}
|
||||
|
||||
func newPageCache() *pageCache {
|
||||
return &pageCache{m: make(map[string][][2]Pages)}
|
||||
}
|
||||
|
||||
// get gets a Pages slice from the cache matching the given key and Pages slice.
|
||||
// If none found in cache, a copy of the supplied slice is created.
|
||||
//
|
||||
// If an apply func is provided, that func is applied to the newly created copy.
|
||||
//
|
||||
// The cache and the execution of the apply func is protected by a RWMutex.
|
||||
func (c *pageCache) get(key string, p Pages, apply func(p Pages)) (Pages, bool) {
|
||||
c.RLock()
|
||||
if cached, ok := c.m[key]; ok {
|
||||
for _, ps := range cached {
|
||||
if probablyEqualPages(p, ps[0]) {
|
||||
c.RUnlock()
|
||||
return ps[1], true
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
c.RUnlock()
|
||||
|
||||
c.Lock()
|
||||
defer c.Unlock()
|
||||
|
||||
// double-check
|
||||
if cached, ok := c.m[key]; ok {
|
||||
for _, ps := range cached {
|
||||
if probablyEqualPages(p, ps[0]) {
|
||||
return ps[1], true
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pagesCopy := append(Pages(nil), p...)
|
||||
|
||||
if v, ok := c.m[key]; ok {
|
||||
c.m[key] = append(v, [2]Pages{p, pagesCopy})
|
||||
} else {
|
||||
c.m[key] = [][2]Pages{[2]Pages{p, pagesCopy}}
|
||||
}
|
||||
|
||||
if apply != nil {
|
||||
apply(pagesCopy)
|
||||
}
|
||||
|
||||
return pagesCopy, false
|
||||
|
||||
}
|
||||
|
||||
// "probably" as in: we do not compare every element for big slices, but that is
|
||||
// good enough for our use case.
|
||||
// TODO(bep) there is a similar method in pagination.go. DRY.
|
||||
func probablyEqualPages(p1, p2 Pages) bool {
|
||||
if p1 == nil && p2 == nil {
|
||||
return true
|
||||
}
|
||||
|
||||
if p1 == nil || p2 == nil {
|
||||
return false
|
||||
}
|
||||
|
||||
if p1.Len() != p2.Len() {
|
||||
return false
|
||||
}
|
||||
|
||||
if p1.Len() == 0 {
|
||||
return true
|
||||
}
|
||||
|
||||
step := 1
|
||||
|
||||
if len(p1) >= 50 {
|
||||
step = len(p1) / 10
|
||||
}
|
||||
|
||||
for i := 0; i < len(p1); i += step {
|
||||
if p1[i] != p2[i] {
|
||||
return false
|
||||
}
|
||||
}
|
||||
return true
|
||||
}
|
||||
60
hugolib/pageCache_test.go
Normal file
60
hugolib/pageCache_test.go
Normal file
|
|
@ -0,0 +1,60 @@
|
|||
package hugolib
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"github.com/stretchr/testify/assert"
|
||||
"sync"
|
||||
"sync/atomic"
|
||||
"testing"
|
||||
)
|
||||
|
||||
func TestPageCache(t *testing.T) {
|
||||
c1 := newPageCache()
|
||||
|
||||
changeFirst := func(p Pages) {
|
||||
p[0].Description = "changed"
|
||||
}
|
||||
|
||||
var o1 uint64 = 0
|
||||
var o2 uint64 = 0
|
||||
|
||||
var wg sync.WaitGroup
|
||||
|
||||
var l1 sync.Mutex
|
||||
var l2 sync.Mutex
|
||||
|
||||
var testPageSets []Pages
|
||||
|
||||
for j := 0; j < 50; j++ {
|
||||
testPageSets = append(testPageSets, createSortTestPages(j+1))
|
||||
}
|
||||
|
||||
for i := 0; i < 100; i++ {
|
||||
wg.Add(1)
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
for j, pages := range testPageSets {
|
||||
msg := fmt.Sprintf("Go %d %d %d %d", i, j, o1, o2)
|
||||
l1.Lock()
|
||||
p, c := c1.get("k1", pages, nil)
|
||||
assert.Equal(t, !atomic.CompareAndSwapUint64(&o1, uint64(j), uint64(j+1)), c, "c1: "+msg)
|
||||
l1.Unlock()
|
||||
p2, c2 := c1.get("k1", p, nil)
|
||||
assert.True(t, c2)
|
||||
assert.True(t, probablyEqualPages(p, p2))
|
||||
assert.True(t, probablyEqualPages(p, pages))
|
||||
assert.NotNil(t, p, msg)
|
||||
|
||||
l2.Lock()
|
||||
p3, c3 := c1.get("k2", pages, changeFirst)
|
||||
assert.Equal(t, !atomic.CompareAndSwapUint64(&o2, uint64(j), uint64(j+1)), c3, "c3: "+msg)
|
||||
l2.Unlock()
|
||||
assert.NotNil(t, p3, msg)
|
||||
assert.Equal(t, p3[0].Description, "changed", msg)
|
||||
}
|
||||
}()
|
||||
}
|
||||
|
||||
wg.Wait()
|
||||
|
||||
}
|
||||
|
|
@ -17,6 +17,8 @@ import (
|
|||
"sort"
|
||||
)
|
||||
|
||||
var spc = newPageCache()
|
||||
|
||||
/*
|
||||
* Implementation of a custom sorter for Pages
|
||||
*/
|
||||
|
|
@ -62,60 +64,121 @@ func (p Pages) Limit(n int) Pages {
|
|||
return p
|
||||
}
|
||||
|
||||
// ByWeight sorts the Pages by weight and returns a copy.
|
||||
//
|
||||
// Adjacent invocactions on the same receiver will return a cached result.
|
||||
//
|
||||
// This may safely be executed in parallel.
|
||||
func (p Pages) ByWeight() Pages {
|
||||
PageBy(DefaultPageSort).Sort(p)
|
||||
return p
|
||||
key := "pageSort.ByWeight"
|
||||
pages, _ := spc.get(key, p, PageBy(DefaultPageSort).Sort)
|
||||
return pages
|
||||
}
|
||||
|
||||
// ByTitle sorts the Pages by title and returns a copy.
|
||||
//
|
||||
// Adjacent invocactions on the same receiver will return a cached result.
|
||||
//
|
||||
// This may safely be executed in parallel.
|
||||
func (p Pages) ByTitle() Pages {
|
||||
|
||||
key := "pageSort.ByTitle"
|
||||
|
||||
title := func(p1, p2 *Page) bool {
|
||||
return p1.Title < p2.Title
|
||||
}
|
||||
|
||||
PageBy(title).Sort(p)
|
||||
return p
|
||||
pages, _ := spc.get(key, p, PageBy(title).Sort)
|
||||
return pages
|
||||
}
|
||||
|
||||
// ByLinkTitle sorts the Pages by link title and returns a copy.
|
||||
//
|
||||
// Adjacent invocactions on the same receiver will return a cached result.
|
||||
//
|
||||
// This may safely be executed in parallel.
|
||||
func (p Pages) ByLinkTitle() Pages {
|
||||
|
||||
key := "pageSort.ByLinkTitle"
|
||||
|
||||
linkTitle := func(p1, p2 *Page) bool {
|
||||
return p1.linkTitle < p2.linkTitle
|
||||
}
|
||||
|
||||
PageBy(linkTitle).Sort(p)
|
||||
return p
|
||||
pages, _ := spc.get(key, p, PageBy(linkTitle).Sort)
|
||||
|
||||
return pages
|
||||
}
|
||||
|
||||
// ByDate sorts the Pages by date and returns a copy.
|
||||
//
|
||||
// Adjacent invocactions on the same receiver will return a cached result.
|
||||
//
|
||||
// This may safely be executed in parallel.
|
||||
func (p Pages) ByDate() Pages {
|
||||
|
||||
key := "pageSort.ByDate"
|
||||
|
||||
date := func(p1, p2 *Page) bool {
|
||||
return p1.Date.Unix() < p2.Date.Unix()
|
||||
}
|
||||
|
||||
PageBy(date).Sort(p)
|
||||
return p
|
||||
pages, _ := spc.get(key, p, PageBy(date).Sort)
|
||||
|
||||
return pages
|
||||
}
|
||||
|
||||
// ByPublishDate sorts the Pages by publish date and returns a copy.
|
||||
//
|
||||
// Adjacent invocactions on the same receiver will return a cached result.
|
||||
//
|
||||
// This may safely be executed in parallel.
|
||||
func (p Pages) ByPublishDate() Pages {
|
||||
|
||||
key := "pageSort.ByPublishDate"
|
||||
|
||||
pubDate := func(p1, p2 *Page) bool {
|
||||
return p1.PublishDate.Unix() < p2.PublishDate.Unix()
|
||||
}
|
||||
|
||||
PageBy(pubDate).Sort(p)
|
||||
return p
|
||||
pages, _ := spc.get(key, p, PageBy(pubDate).Sort)
|
||||
|
||||
return pages
|
||||
}
|
||||
|
||||
// ByLength sorts the Pages by length and returns a copy.
|
||||
//
|
||||
// Adjacent invocactions on the same receiver will return a cached result.
|
||||
//
|
||||
// This may safely be executed in parallel.
|
||||
func (p Pages) ByLength() Pages {
|
||||
|
||||
key := "pageSort.ByLength"
|
||||
|
||||
length := func(p1, p2 *Page) bool {
|
||||
return len(p1.Content) < len(p2.Content)
|
||||
}
|
||||
|
||||
PageBy(length).Sort(p)
|
||||
return p
|
||||
pages, _ := spc.get(key, p, PageBy(length).Sort)
|
||||
|
||||
return pages
|
||||
}
|
||||
|
||||
// Reverse reverses the order in Pages and returns a copy.
|
||||
//
|
||||
// Adjacent invocactions on the same receiver will return a cached result.
|
||||
//
|
||||
// This may safely be executed in parallel.
|
||||
func (p Pages) Reverse() Pages {
|
||||
for i, j := 0, len(p)-1; i < j; i, j = i+1, j-1 {
|
||||
p[i], p[j] = p[j], p[i]
|
||||
key := "pageSort.Reverse"
|
||||
|
||||
reverseFunc := func(pages Pages) {
|
||||
for i, j := 0, len(pages)-1; i < j; i, j = i+1, j-1 {
|
||||
pages[i], pages[j] = pages[j], pages[i]
|
||||
}
|
||||
}
|
||||
|
||||
return p
|
||||
pages, _ := spc.get(key, p, reverseFunc)
|
||||
|
||||
return pages
|
||||
}
|
||||
|
|
|
|||
|
|
@ -10,12 +10,14 @@ import (
|
|||
)
|
||||
|
||||
func TestPageSortReverse(t *testing.T) {
|
||||
p := createSortTestPages(10)
|
||||
assert.Equal(t, 0, p[0].FuzzyWordCount)
|
||||
assert.Equal(t, 9, p[9].FuzzyWordCount)
|
||||
p = p.Reverse()
|
||||
assert.Equal(t, 9, p[0].FuzzyWordCount)
|
||||
assert.Equal(t, 0, p[9].FuzzyWordCount)
|
||||
p1 := createSortTestPages(10)
|
||||
assert.Equal(t, 0, p1[0].FuzzyWordCount)
|
||||
assert.Equal(t, 9, p1[9].FuzzyWordCount)
|
||||
p2 := p1.Reverse()
|
||||
assert.Equal(t, 9, p2[0].FuzzyWordCount)
|
||||
assert.Equal(t, 0, p2[9].FuzzyWordCount)
|
||||
// cached
|
||||
assert.True(t, probablyEqualPages(p2, p1.Reverse()))
|
||||
}
|
||||
|
||||
func BenchmarkSortByWeightAndReverse(b *testing.B) {
|
||||
|
|
@ -51,6 +53,7 @@ func createSortTestPages(num int) Pages {
|
|||
}
|
||||
pages[i].FuzzyWordCount = i
|
||||
pages[i].Weight = w
|
||||
pages[i].Description = "initial"
|
||||
}
|
||||
|
||||
return pages
|
||||
|
|
|
|||
Loading…
Reference in a new issue