ref: bd98182dbde893a8a809661c70633741bbf63911
dir: /resources/image_cache.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 (
"image"
"io"
"path/filepath"
"strings"
"sync"
"github.com/gohugoio/hugo/common/hugio"
"github.com/gohugoio/hugo/cache/filecache"
"github.com/gohugoio/hugo/helpers"
)
type imageCache struct {
pathSpec *helpers.PathSpec
fileCache *filecache.Cache
mu sync.RWMutex
store map[string]*Image
}
func (c *imageCache) isInCache(key string) bool {
c.mu.RLock()
_, found := c.store[c.normalizeKey(key)]
c.mu.RUnlock()
return found
}
func (c *imageCache) deleteByPrefix(prefix string) {
c.mu.Lock()
defer c.mu.Unlock()
prefix = c.normalizeKey(prefix)
for k := range c.store {
if strings.HasPrefix(k, prefix) {
delete(c.store, k)
}
}
}
func (c *imageCache) normalizeKey(key string) string {
// It is a path with Unix style slashes and it always starts with a leading slash.
key = filepath.ToSlash(key)
if !strings.HasPrefix(key, "/") {
key = "/" + key
}
return key
}
func (c *imageCache) clear() {
c.mu.Lock()
defer c.mu.Unlock()
c.store = make(map[string]*Image)
}
func (c *imageCache) getOrCreate(
parent *Image, conf imageConfig, createImage func() (*Image, image.Image, error)) (*Image, error) {
relTarget := parent.relTargetPathFromConfig(conf)
key := parent.relTargetPathForRel(relTarget.path(), false, false, false)
// First check the in-memory store, then the disk.
c.mu.RLock()
img, found := c.store[key]
c.mu.RUnlock()
if found {
return img, nil
}
// These funcs are protected by a named lock.
// read clones the parent to its new name and copies
// the content to the destinations.
read := func(info filecache.ItemInfo, r io.Reader) error {
img = parent.clone()
img.relTargetDirFile.file = relTarget.file
img.sourceFilename = info.Name
// Make sure it's always loaded by sourceFilename.
img.openReadSeekerCloser = nil
w, err := img.openDestinationsForWriting()
if err != nil {
return err
}
if w == nil {
// Nothing to write.
return nil
}
defer w.Close()
_, err = io.Copy(w, r)
return err
}
// create creates the image and encodes it to w (cache) and to its destinations.
create := func(info filecache.ItemInfo, w io.WriteCloser) (err error) {
var conv image.Image
img, conv, err = createImage()
if err != nil {
w.Close()
return
}
img.relTargetDirFile.file = relTarget.file
img.sourceFilename = info.Name
destinations, err := img.openDestinationsForWriting()
if err != nil {
w.Close()
return err
}
if destinations != nil {
w = hugio.NewMultiWriteCloser(w, destinations)
}
defer w.Close()
return img.encodeTo(conf, conv, w)
}
// Now look in the file cache.
// The definition of this counter is not that we have processed that amount
// (e.g. resized etc.), it can be fetched from file cache,
// but the count of processed image variations for this site.
c.pathSpec.ProcessingStats.Incr(&c.pathSpec.ProcessingStats.ProcessedImages)
_, err := c.fileCache.ReadOrCreate(key, read, create)
if err != nil {
return nil, err
}
// The file is now stored in this cache.
img.sourceFs = c.fileCache.Fs
c.mu.Lock()
if img2, found := c.store[key]; found {
c.mu.Unlock()
return img2, nil
}
c.store[key] = img
c.mu.Unlock()
return img, nil
}
func newImageCache(fileCache *filecache.Cache, ps *helpers.PathSpec) *imageCache {
return &imageCache{fileCache: fileCache, pathSpec: ps, store: make(map[string]*Image)}
}