hugo/resource/bundler/bundler.go
2018-09-03 09:22:42 +02:00

121 lines
3.4 KiB
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 bundler contains functions for concatenation etc. of Resource objects.
package bundler
import (
"fmt"
"io"
"path/filepath"
"github.com/gohugoio/hugo/common/hugio"
"github.com/gohugoio/hugo/media"
"github.com/gohugoio/hugo/resource"
)
// Client contains methods perform concatenation and other bundling related
// tasks to Resource objects.
type Client struct {
rs *resource.Spec
}
// New creates a new Client with the given specification.
func New(rs *resource.Spec) *Client {
return &Client{rs: rs}
}
type multiReadSeekCloser struct {
mr io.Reader
sources []hugio.ReadSeekCloser
}
func (r *multiReadSeekCloser) Read(p []byte) (n int, err error) {
return r.mr.Read(p)
}
func (r *multiReadSeekCloser) Seek(offset int64, whence int) (newOffset int64, err error) {
for _, s := range r.sources {
newOffset, err = s.Seek(offset, whence)
if err != nil {
return
}
}
return
}
func (r *multiReadSeekCloser) Close() error {
for _, s := range r.sources {
s.Close()
}
return nil
}
// Concat concatenates the list of Resource objects.
func (c *Client) Concat(targetPath string, resources resource.Resources) (resource.Resource, error) {
// The CACHE_OTHER will make sure this will be re-created and published on rebuilds.
return c.rs.ResourceCache.GetOrCreate(resource.CACHE_OTHER, targetPath, func() (resource.Resource, error) {
var resolvedm media.Type
// The given set of resources must be of the same Media Type.
// We may improve on that in the future, but then we need to know more.
for i, r := range resources {
if i > 0 && r.MediaType().Type() != resolvedm.Type() {
return nil, fmt.Errorf("resources in Concat must be of the same Media Type, got %q and %q", r.MediaType().Type(), resolvedm.Type())
}
resolvedm = r.MediaType()
}
concatr := func() (hugio.ReadSeekCloser, error) {
var rcsources []hugio.ReadSeekCloser
for _, s := range resources {
rcr, ok := s.(resource.ReadSeekCloserResource)
if !ok {
return nil, fmt.Errorf("resource %T does not implement resource.ReadSeekerCloserResource", s)
}
rc, err := rcr.ReadSeekCloser()
if err != nil {
// Close the already opened.
for _, rcs := range rcsources {
rcs.Close()
}
return nil, err
}
rcsources = append(rcsources, rc)
}
readers := make([]io.Reader, len(rcsources))
for i := 0; i < len(rcsources); i++ {
readers[i] = rcsources[i]
}
mr := io.MultiReader(readers...)
return &multiReadSeekCloser{mr: mr, sources: rcsources}, nil
}
composite, err := c.rs.NewForFs(
c.rs.BaseFs.Resources.Fs,
resource.ResourceSourceDescriptor{
LazyPublish: true,
OpenReadSeekCloser: concatr,
RelTargetFilename: filepath.Clean(targetPath)})
if err != nil {
return nil, err
}
return composite, nil
})
}