hugo/tpl/images/images.go

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// Copyright 2017 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 images
import (
"errors"
"image"
"sync"
// Importing image codecs for image.DecodeConfig
_ "image/gif"
_ "image/jpeg"
_ "image/png"
_ "golang.org/x/image/webp"
"github.com/gohugoio/hugo/deps"
"github.com/spf13/cast"
)
// New returns a new instance of the images-namespaced template functions.
func New(deps *deps.Deps) *Namespace {
return &Namespace{
cache: map[string]image.Config{},
deps: deps,
}
}
// Namespace provides template functions for the "images" namespace.
type Namespace struct {
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cacheMu sync.RWMutex
cache map[string]image.Config
deps *deps.Deps
}
// Config returns the image.Config for the specified path relative to the
// working directory.
func (ns *Namespace) Config(path interface{}) (image.Config, error) {
filename, err := cast.ToStringE(path)
if err != nil {
return image.Config{}, err
}
if filename == "" {
return image.Config{}, errors.New("config needs a filename")
}
// Check cache for image config.
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ns.cacheMu.RLock()
config, ok := ns.cache[filename]
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ns.cacheMu.RUnlock()
if ok {
return config, nil
}
f, err := ns.deps.Fs.WorkingDir.Open(filename)
if err != nil {
return image.Config{}, err
}
config, _, err = image.DecodeConfig(f)
if err != nil {
return config, err
}
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ns.cacheMu.Lock()
ns.cache[filename] = config
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ns.cacheMu.Unlock()
return config, nil
}