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hugo/markup/rst/convert.go

135 lines
3.8 KiB
Go

// 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 rst converts content to HTML using the RST external helper.
package rst
import (
"bytes"
"runtime"
"github.com/gohugoio/hugo/common/hexec"
"github.com/gohugoio/hugo/htesting"
"github.com/gohugoio/hugo/identity"
"github.com/gohugoio/hugo/markup/converter"
"github.com/gohugoio/hugo/markup/internal"
)
// 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("rst", func(ctx converter.DocumentContext) (converter.Converter, error) {
return &rstConverter{
ctx: ctx,
cfg: cfg,
}, nil
}), nil
}
type rstConverter struct {
ctx converter.DocumentContext
cfg converter.ProviderConfig
}
func (c *rstConverter) Convert(ctx converter.RenderContext) (converter.ResultRender, error) {
b, err := c.getRstContent(ctx.Src, c.ctx)
if err != nil {
return nil, err
}
return converter.Bytes(b), nil
}
func (c *rstConverter) Supports(feature identity.Identity) bool {
return false
}
// getRstContent calls the Python script rst2html as an external helper
// to convert reStructuredText content to HTML.
func (c *rstConverter) getRstContent(src []byte, ctx converter.DocumentContext) ([]byte, error) {
logger := c.cfg.Logger
binaryName, binaryPath := getRstBinaryNameAndPath()
if binaryName == "" {
logger.Println("rst2html / rst2html.py not found in $PATH: Please install.\n",
" Leaving reStructuredText content unrendered.")
return src, nil
}
logger.Infoln("Rendering", ctx.DocumentName, "with", binaryName, "...")
var result []byte
var err error
// certain *nix based OSs wrap executables in scripted launchers
// invoking binaries on these OSs via python interpreter causes SyntaxError
// invoke directly so that shebangs work as expected
// handle Windows manually because it doesn't do shebangs
if runtime.GOOS == "windows" {
pythonBinary, _ := internal.GetPythonBinaryAndExecPath()
args := []string{binaryPath, "--leave-comments", "--initial-header-level=2"}
result, err = internal.ExternallyRenderContent(c.cfg, ctx, src, pythonBinary, args)
} else {
args := []string{"--leave-comments", "--initial-header-level=2"}
result, err = internal.ExternallyRenderContent(c.cfg, ctx, src, binaryName, args)
}
if err != nil {
return nil, err
}
// TODO(bep) check if rst2html has a body only option.
bodyStart := bytes.Index(result, []byte("<body>\n"))
if bodyStart < 0 {
bodyStart = -7 // compensate for length
}
bodyEnd := bytes.Index(result, []byte("\n</body>"))
if bodyEnd < 0 || bodyEnd >= len(result) {
bodyEnd = len(result) - 1
if bodyEnd < 0 {
bodyEnd = 0
}
}
return result[bodyStart+7 : bodyEnd], err
}
var rst2Binaries = []string{"rst2html", "rst2html.py"}
func getRstBinaryNameAndPath() (string, string) {
for _, candidate := range rst2Binaries {
if pth := hexec.LookPath(candidate); pth != "" {
return candidate, pth
}
}
return "", ""
}
// Supports returns whether rst is (or should be) installed on this computer.
func Supports() bool {
name, _ := getRstBinaryNameAndPath()
hasBin := name != ""
if htesting.SupportsAll() {
if !hasBin {
panic("rst not installed")
}
return true
}
return hasBin
}