1 files changed, 112 insertions, 0 deletions
diff --git a/resource/image_cache.go b/resource/image_cache.go
new file mode 100644
index 000000000..14350986e
--- /dev/null
+++ b/resource/image_cache.go
@@ -0,0 +1,112 @@
+// Copyright 2017-present 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"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/gohugoio/hugo/helpers"
+)
+
+type imageCache struct {
+	absPublishDir string
+	absCacheDir   string
+	pathSpec      *helpers.PathSpec
+	mu            sync.RWMutex
+	store         map[string]*Image
+}
+
+func (c *imageCache) isInCache(key string) bool {
+	c.mu.RLock()
+	_, found := c.store[key]
+	c.mu.RUnlock()
+	return found
+}
+
+func (c *imageCache) deleteByPrefix(prefix string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for k, _ := range c.store {
+		if strings.HasPrefix(k, prefix) {
+			delete(c.store, k)
+		}
+	}
+}
+
+func (c *imageCache) getOrCreate(
+	spec *Spec, key string, create func(resourceCacheFilename string) (*Image, error)) (*Image, error) {
+	// 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.
+	cacheFilename := filepath.Join(c.absCacheDir, 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)
+
+	r, err := spec.NewResourceFromFilename(nil, c.absPublishDir, cacheFilename, key)
+	notFound := err != nil && os.IsNotExist(err)
+	if err != nil && !os.IsNotExist(err) {
+		return nil, err
+	}
+
+	if notFound {
+		img, err = create(cacheFilename)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		img = r.(*Image)
+	}
+
+	c.mu.Lock()
+	if img2, found := c.store[key]; found {
+		c.mu.Unlock()
+		return img2, nil
+	}
+
+	c.store[key] = img
+
+	c.mu.Unlock()
+
+	if notFound {
+		// File already written to destination
+		return img, nil
+	}
+
+	return img, img.copyToDestination(cacheFilename)
+
+}
+
+func newImageCache(ps *helpers.PathSpec, absCacheDir, absPublishDir string) *imageCache {
+	return &imageCache{pathSpec: ps, store: make(map[string]*Image), absCacheDir: absCacheDir, absPublishDir: absPublishDir}
+}
+
+func timeTrack(start time.Time, name string) {
+	elapsed := time.Since(start)
+	fmt.Printf("%s took %s\n", name, elapsed)
+}