hugo/hugolib/handler_meta.go
2017-08-08 10:54:35 +02:00

128 lines
3.1 KiB
Go

// Copyright 2015 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 hugolib
import (
"errors"
"fmt"
"github.com/gohugoio/hugo/source"
)
var handlers []Handler
// MetaHandler abstracts reading and converting functionality of a Handler.
type MetaHandler interface {
// Read the Files in and register
Read(*source.File, *Site, HandleResults)
// Generic Convert Function with coordination
Convert(interface{}, *Site, HandleResults)
Handle() Handler
}
// HandledResults is a channel for HandledResult.
type HandleResults chan<- HandledResult
// NewMetaHandler creates a MetaHandle for a given extensions.
func NewMetaHandler(in string) *MetaHandle {
x := &MetaHandle{ext: in}
x.Handler()
return x
}
// MetaHandle is a generic MetaHandler that internally uses
// the globally registered handlers for handling specific file types.
type MetaHandle struct {
handler Handler
ext string
}
func (mh *MetaHandle) Read(f *source.File, s *Site, results HandleResults) {
if h := mh.Handler(); h != nil {
results <- h.Read(f, s)
return
}
results <- HandledResult{err: errors.New("No handler found"), file: f}
}
// Convert handles the conversion of files and pages.
func (mh *MetaHandle) Convert(i interface{}, s *Site, results HandleResults) {
h := mh.Handler()
if f, ok := i.(*source.File); ok {
results <- h.FileConvert(f, s)
return
}
if p, ok := i.(*Page); ok {
if p == nil {
results <- HandledResult{err: errors.New("file resulted in a nil page")}
return
}
if h == nil {
results <- HandledResult{err: fmt.Errorf("No handler found for page '%s'. Verify the markup is supported by Hugo.", p.FullFilePath())}
return
}
results <- h.PageConvert(p)
}
}
// Handler finds the registered handler for the used extensions.
func (mh *MetaHandle) Handler() Handler {
if mh.handler == nil {
mh.handler = FindHandler(mh.ext)
// if no handler found, use default handler
if mh.handler == nil {
mh.handler = FindHandler("*")
}
}
return mh.handler
}
// FindHandler finds a Handler in the globally registered handlers.
func FindHandler(ext string) Handler {
for _, h := range Handlers() {
if HandlerMatch(h, ext) {
return h
}
}
return nil
}
// HandlerMatch checks if the given extensions matches.
func HandlerMatch(h Handler, ext string) bool {
for _, x := range h.Extensions() {
if ext == x {
return true
}
}
return false
}
// RegisterHandler adds a handler to the globally registered ones.
func RegisterHandler(h Handler) {
handlers = append(handlers, h)
}
// Handlers returns the globally registered handlers.
func Handlers() []Handler {
return handlers
}