hugo/resources/resource_cache.go
Bjørn Erik Pedersen f9978ed164
Image resource refactor
This commit pulls most of the image related logic into its own package, to make it easier to reason about and extend.

This is also a rewrite of the transformation logic used in Hugo Pipes, mostly to allow constructs like the one below:

    {{ ($myimg | fingerprint ).Width }}

Fixes #5903
Fixes #6234
Fixes #6266
2019-08-26 15:00:44 +02:00

297 lines
6.9 KiB
Go

// Copyright 2019 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache 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://www.apache.org/licenses/LICENSE-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 resources
import (
"encoding/json"
"io"
"path"
"path/filepath"
"strings"
"sync"
"github.com/gohugoio/hugo/helpers"
"github.com/gohugoio/hugo/hugofs/glob"
"github.com/gohugoio/hugo/resources/resource"
"github.com/gohugoio/hugo/cache/filecache"
"github.com/BurntSushi/locker"
)
const (
CACHE_CLEAR_ALL = "clear_all"
CACHE_OTHER = "other"
)
type ResourceCache struct {
rs *Spec
sync.RWMutex
// Either resource.Resource or resource.Resources.
cache map[string]interface{}
fileCache *filecache.Cache
// Provides named resource locks.
nlocker *locker.Locker
}
// ResourceCacheKey converts the filename into the format used in the resource
// cache.
func ResourceCacheKey(filename string) string {
filename = filepath.ToSlash(filename)
return path.Join(resourceKeyPartition(filename), filename)
}
func resourceKeyPartition(filename string) string {
ext := strings.TrimPrefix(path.Ext(filepath.ToSlash(filename)), ".")
if ext == "" {
ext = CACHE_OTHER
}
return ext
}
// Commonly used aliases and directory names used for some types.
var extAliasKeywords = map[string][]string{
"sass": []string{"scss"},
"scss": []string{"sass"},
}
// ResourceKeyPartitions resolves a ordered slice of partitions that is
// used to do resource cache invalidations.
//
// We use the first directory path element and the extension, so:
// a/b.json => "a", "json"
// b.json => "json"
//
// For some of the extensions we will also map to closely related types,
// e.g. "scss" will also return "sass".
//
func ResourceKeyPartitions(filename string) []string {
var partitions []string
filename = glob.NormalizePath(filename)
dir, name := path.Split(filename)
ext := strings.TrimPrefix(path.Ext(filepath.ToSlash(name)), ".")
if dir != "" {
partitions = append(partitions, strings.Split(dir, "/")[0])
}
if ext != "" {
partitions = append(partitions, ext)
}
if aliases, found := extAliasKeywords[ext]; found {
partitions = append(partitions, aliases...)
}
if len(partitions) == 0 {
partitions = []string{CACHE_OTHER}
}
return helpers.UniqueStringsSorted(partitions)
}
// ResourceKeyContainsAny returns whether the key is a member of any of the
// given partitions.
//
// This is used for resource cache invalidation.
func ResourceKeyContainsAny(key string, partitions []string) bool {
parts := strings.Split(key, "/")
for _, p1 := range partitions {
for _, p2 := range parts {
if p1 == p2 {
return true
}
}
}
return false
}
func newResourceCache(rs *Spec) *ResourceCache {
return &ResourceCache{
rs: rs,
fileCache: rs.FileCaches.AssetsCache(),
cache: make(map[string]interface{}),
nlocker: locker.NewLocker(),
}
}
func (c *ResourceCache) clear() {
c.Lock()
defer c.Unlock()
c.cache = make(map[string]interface{})
c.nlocker = locker.NewLocker()
}
func (c *ResourceCache) Contains(key string) bool {
key = c.cleanKey(filepath.ToSlash(key))
_, found := c.get(key)
return found
}
func (c *ResourceCache) cleanKey(key string) string {
return strings.TrimPrefix(path.Clean(strings.ToLower(key)), "/")
}
func (c *ResourceCache) get(key string) (interface{}, bool) {
c.RLock()
defer c.RUnlock()
r, found := c.cache[key]
return r, found
}
func (c *ResourceCache) GetOrCreate(key string, f func() (resource.Resource, error)) (resource.Resource, error) {
r, err := c.getOrCreate(key, func() (interface{}, error) { return f() })
if r == nil || err != nil {
return nil, err
}
return r.(resource.Resource), nil
}
func (c *ResourceCache) GetOrCreateResources(key string, f func() (resource.Resources, error)) (resource.Resources, error) {
r, err := c.getOrCreate(key, func() (interface{}, error) { return f() })
if r == nil || err != nil {
return nil, err
}
return r.(resource.Resources), nil
}
func (c *ResourceCache) getOrCreate(key string, f func() (interface{}, error)) (interface{}, error) {
key = c.cleanKey(key)
// First check in-memory cache.
r, found := c.get(key)
if found {
return r, nil
}
// This is a potentially long running operation, so get a named lock.
c.nlocker.Lock(key)
// Double check in-memory cache.
r, found = c.get(key)
if found {
c.nlocker.Unlock(key)
return r, nil
}
defer c.nlocker.Unlock(key)
r, err := f()
if err != nil {
return nil, err
}
c.set(key, r)
return r, nil
}
func (c *ResourceCache) getFilenames(key string) (string, string) {
filenameMeta := key + ".json"
filenameContent := key + ".content"
return filenameMeta, filenameContent
}
func (c *ResourceCache) getFromFile(key string) (filecache.ItemInfo, io.ReadCloser, transformedResourceMetadata, bool) {
c.RLock()
defer c.RUnlock()
var meta transformedResourceMetadata
filenameMeta, filenameContent := c.getFilenames(key)
_, jsonContent, _ := c.fileCache.GetBytes(filenameMeta)
if jsonContent == nil {
return filecache.ItemInfo{}, nil, meta, false
}
if err := json.Unmarshal(jsonContent, &meta); err != nil {
return filecache.ItemInfo{}, nil, meta, false
}
fi, rc, _ := c.fileCache.Get(filenameContent)
return fi, rc, meta, rc != nil
}
// writeMeta writes the metadata to file and returns a writer for the content part.
func (c *ResourceCache) writeMeta(key string, meta transformedResourceMetadata) (filecache.ItemInfo, io.WriteCloser, error) {
filenameMeta, filenameContent := c.getFilenames(key)
raw, err := json.Marshal(meta)
if err != nil {
return filecache.ItemInfo{}, nil, err
}
_, fm, err := c.fileCache.WriteCloser(filenameMeta)
if err != nil {
return filecache.ItemInfo{}, nil, err
}
defer fm.Close()
if _, err := fm.Write(raw); err != nil {
return filecache.ItemInfo{}, nil, err
}
fi, fc, err := c.fileCache.WriteCloser(filenameContent)
return fi, fc, err
}
func (c *ResourceCache) set(key string, r interface{}) {
c.Lock()
defer c.Unlock()
c.cache[key] = r
}
func (c *ResourceCache) DeletePartitions(partitions ...string) {
partitionsSet := map[string]bool{
// Always clear out the resources not matching any partition.
"other": true,
}
for _, p := range partitions {
partitionsSet[p] = true
}
if partitionsSet[CACHE_CLEAR_ALL] {
c.clear()
return
}
c.Lock()
defer c.Unlock()
for k := range c.cache {
clear := false
for p := range partitionsSet {
if strings.Contains(k, p) {
// There will be some false positive, but that's fine.
clear = true
break
}
}
if clear {
delete(c.cache, k)
}
}
}