hugo/markup/pandoc/convert.go

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// Copyright 2019 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 pandoc converts content to HTML using Pandoc as an external helper.
package pandoc
import (
"github.com/gohugoio/hugo/common/hexec"
"github.com/gohugoio/hugo/htesting"
"github.com/gohugoio/hugo/identity"
"github.com/gohugoio/hugo/markup/internal"
"github.com/gohugoio/hugo/markup/converter"
)
// Provider is the package entry point.
var Provider converter.ProviderProvider = provider{}
type provider struct {
}
func (p provider) New(cfg converter.ProviderConfig) (converter.Provider, error) {
return converter.NewProvider("pandoc", func(ctx converter.DocumentContext) (converter.Converter, error) {
return &pandocConverter{
ctx: ctx,
cfg: cfg,
}, nil
}), nil
}
type pandocConverter struct {
ctx converter.DocumentContext
cfg converter.ProviderConfig
}
func (c *pandocConverter) Convert(ctx converter.RenderContext) (converter.Result, error) {
b, err := c.getPandocContent(ctx.Src, c.ctx)
if err != nil {
return nil, err
}
return converter.Bytes(b), nil
}
func (c *pandocConverter) Supports(feature identity.Identity) bool {
return false
}
// getPandocContent calls pandoc as an external helper to convert pandoc markdown to HTML.
func (c *pandocConverter) getPandocContent(src []byte, ctx converter.DocumentContext) ([]byte, error) {
logger := c.cfg.Logger
binaryName := getPandocBinaryName()
if binaryName == "" {
logger.Println("pandoc not found in $PATH: Please install.\n",
" Leaving pandoc content unrendered.")
return src, nil
}
args := []string{"--mathjax"}
return internal.ExternallyRenderContent(c.cfg, ctx, src, binaryName, args)
}
const pandocBinary = "pandoc"
func getPandocBinaryName() string {
if hexec.InPath(pandocBinary) {
return pandocBinary
}
return ""
}
// Supports returns whether Pandoc is installed on this computer.
func Supports() bool {
hasBin := getPandocBinaryName() != ""
if htesting.SupportsAll() {
if !hasBin {
panic("pandoc not installed")
}
return true
}
return hasBin
}