ref: ef20ec1fbaa8f5841b3fbe18978d4d8c19d8fc53
dir: /resource/image_cache.go/
// Copyright 2018 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 resource
import (
"fmt"
"path/filepath"
"strings"
"sync"
"time"
"github.com/gohugoio/hugo/helpers"
)
type imageCache struct {
cacheDir string
pathSpec *helpers.PathSpec
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, create func(resourceCacheFilename string) (*Image, error)) (*Image, error) {
relTarget := parent.relTargetPathFromConfig(conf)
key := parent.relTargetPathForRel(relTarget.path(), 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
}
// Now look in the file cache.
// Multiple Go routines can invoke same operation on the same image, so
// we need to make sure this is serialized per source image.
parent.createMu.Lock()
defer parent.createMu.Unlock()
cacheFilename := filepath.Join(c.cacheDir, key)
// 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)
exists, err := helpers.Exists(cacheFilename, c.pathSpec.BaseFs.Resources.Fs)
if err != nil {
return nil, err
}
if exists {
img = parent.clone()
} else {
img, err = create(cacheFilename)
if err != nil {
return nil, err
}
}
img.relTargetDirFile.file = relTarget.file
img.sourceFilename = cacheFilename
// We have to look in the resources file system for this.
img.overriddenSourceFs = img.spec.BaseFs.Resources.Fs
c.mu.Lock()
if img2, found := c.store[key]; found {
c.mu.Unlock()
return img2, nil
}
c.store[key] = img
c.mu.Unlock()
if !exists {
// File already written to destination
return img, nil
}
return img, img.copyToDestination(cacheFilename)
}
func newImageCache(ps *helpers.PathSpec, cacheDir string) *imageCache {
return &imageCache{pathSpec: ps, store: make(map[string]*Image), cacheDir: cacheDir}
}
func timeTrack(start time.Time, name string) {
elapsed := time.Since(start)
fmt.Printf("%s took %s\n", name, elapsed)
}