hugo/resources/image_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

159 lines
3.9 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 (
"image"
"io"
"path/filepath"
"strings"
"sync"
"github.com/gohugoio/hugo/resources/images"
"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]*resourceAdapter
}
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]*resourceAdapter)
}
func (c *imageCache) getOrCreate(
parent *imageResource, conf images.ImageConfig,
createImage func() (*imageResource, image.Image, error)) (*resourceAdapter, 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()
cachedImage, found := c.store[key]
c.mu.RUnlock()
if found {
return cachedImage, nil
}
var img *imageResource
// 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(nil)
rp := img.getResourcePaths()
rp.relTargetDirFile.file = relTarget.file
img.setSourceFilename(info.Name)
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 the cache (w).
create := func(info filecache.ItemInfo, w io.WriteCloser) (err error) {
defer w.Close()
var conv image.Image
img, conv, err = createImage()
if err != nil {
return
}
rp := img.getResourcePaths()
rp.relTargetDirFile.file = relTarget.file
img.setSourceFilename(info.Name)
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.setSourceFs(c.fileCache.Fs)
c.mu.Lock()
if cachedImage, found = c.store[key]; found {
c.mu.Unlock()
return cachedImage, nil
}
imgAdapter := newResourceAdapter(parent.getSpec(), true, img)
c.store[key] = imgAdapter
c.mu.Unlock()
return imgAdapter, nil
}
func newImageCache(fileCache *filecache.Cache, ps *helpers.PathSpec) *imageCache {
return &imageCache{fileCache: fileCache, pathSpec: ps, store: make(map[string]*resourceAdapter)}
}