ref: 2c4e76e9626960c0a8935e139d01dcb94d6f8b23
dir: /resources/resource_transformers/postcss/postcss.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 postcss
import (
"bytes"
"crypto/sha256"
"encoding/hex"
"io"
"io/ioutil"
"path"
"path/filepath"
"regexp"
"strconv"
"strings"
"github.com/gohugoio/hugo/common/hugo"
"github.com/gohugoio/hugo/common/loggers"
"github.com/gohugoio/hugo/resources/internal"
"github.com/spf13/afero"
"github.com/spf13/cast"
"github.com/gohugoio/hugo/hugofs"
"github.com/pkg/errors"
"os/exec"
"github.com/mitchellh/mapstructure"
"github.com/gohugoio/hugo/common/herrors"
"github.com/gohugoio/hugo/resources"
"github.com/gohugoio/hugo/resources/resource"
)
const importIdentifier = "@import"
var cssSyntaxErrorRe = regexp.MustCompile(`> (\d+) \|`)
var shouldImportRe = regexp.MustCompile(`^@import ["'].*["'];?\s*(/\*.*\*/)?$`)
// New creates a new Client with the given specification.
func New(rs *resources.Spec) *Client {
return &Client{rs: rs}
}
func DecodeOptions(m map[string]interface{}) (opts Options, err error) {
if m == nil {
return
}
err = mapstructure.WeakDecode(m, &opts)
if !opts.NoMap {
// There was for a long time a discrepancy between documentation and
// implementation for the noMap property, so we need to support both
// camel and snake case.
opts.NoMap = cast.ToBool(m["no-map"])
}
return
}
// Client is the client used to do PostCSS transformations.
type Client struct {
rs *resources.Spec
}
// Process transforms the given Resource with the PostCSS processor.
func (c *Client) Process(res resources.ResourceTransformer, options Options) (resource.Resource, error) {
return res.Transform(&postcssTransformation{rs: c.rs, options: options})
}
// Some of the options from https://github.com/postcss/postcss-cli
type Options struct {
// Set a custom path to look for a config file.
Config string
NoMap bool // Disable the default inline sourcemaps
// Enable inlining of @import statements.
// Does so recursively, but currently once only per file;
// that is, it's not possible to import the same file in
// different scopes (root, media query...)
// Note that this import routine does not care about the CSS spec,
// so you can have @import anywhere in the file.
InlineImports bool
// Options for when not using a config file
Use string // List of postcss plugins to use
Parser string // Custom postcss parser
Stringifier string // Custom postcss stringifier
Syntax string // Custom postcss syntax
}
func (opts Options) toArgs() []string {
var args []string
if opts.NoMap {
args = append(args, "--no-map")
}
if opts.Use != "" {
args = append(args, "--use", opts.Use)
}
if opts.Parser != "" {
args = append(args, "--parser", opts.Parser)
}
if opts.Stringifier != "" {
args = append(args, "--stringifier", opts.Stringifier)
}
if opts.Syntax != "" {
args = append(args, "--syntax", opts.Syntax)
}
return args
}
type postcssTransformation struct {
options Options
rs *resources.Spec
}
func (t *postcssTransformation) Key() internal.ResourceTransformationKey {
return internal.NewResourceTransformationKey("postcss", t.options)
}
// Transform shells out to postcss-cli to do the heavy lifting.
// For this to work, you need some additional tools. To install them globally:
// npm install -g postcss-cli
// npm install -g autoprefixer
func (t *postcssTransformation) Transform(ctx *resources.ResourceTransformationCtx) error {
const localPostCSSPath = "node_modules/.bin/"
const binaryName = "postcss"
// Try first in the project's node_modules.
csiBinPath := filepath.Join(t.rs.WorkingDir, localPostCSSPath, binaryName)
binary := csiBinPath
if _, err := exec.LookPath(binary); err != nil {
// Try PATH
binary = binaryName
if _, err := exec.LookPath(binary); err != nil {
// This may be on a CI server etc. Will fall back to pre-built assets.
return herrors.ErrFeatureNotAvailable
}
}
var configFile string
logger := t.rs.Logger
if t.options.Config != "" {
configFile = t.options.Config
} else {
configFile = "postcss.config.js"
}
configFile = filepath.Clean(configFile)
// We need an abolute filename to the config file.
if !filepath.IsAbs(configFile) {
configFile = t.rs.BaseFs.ResolveJSConfigFile(configFile)
if configFile == "" && t.options.Config != "" {
// Only fail if the user specificed config file is not found.
return errors.Errorf("postcss config %q not found:", configFile)
}
}
var cmdArgs []string
if configFile != "" {
logger.INFO.Println("postcss: use config file", configFile)
cmdArgs = []string{"--config", configFile}
}
if optArgs := t.options.toArgs(); len(optArgs) > 0 {
cmdArgs = append(cmdArgs, optArgs...)
}
cmd := exec.Command(binary, cmdArgs...)
var errBuf bytes.Buffer
infoW := loggers.LoggerToWriterWithPrefix(logger.INFO, "postcss")
cmd.Stdout = ctx.To
cmd.Stderr = io.MultiWriter(infoW, &errBuf)
cmd.Env = hugo.GetExecEnviron(t.rs.WorkingDir, t.rs.Cfg, t.rs.BaseFs.Assets.Fs)
stdin, err := cmd.StdinPipe()
if err != nil {
return err
}
src := ctx.From
imp := newImportResolver(
ctx.From,
ctx.InPath,
t.rs.Assets.Fs, t.rs.Logger,
)
if t.options.InlineImports {
var err error
src, err = imp.resolve()
if err != nil {
return err
}
}
go func() {
defer stdin.Close()
io.Copy(stdin, src)
}()
err = cmd.Run()
if err != nil {
return imp.toFileError(errBuf.String())
}
return nil
}
type fileOffset struct {
Filename string
Offset int
}
type importResolver struct {
r io.Reader
inPath string
contentSeen map[string]bool
linemap map[int]fileOffset
fs afero.Fs
logger *loggers.Logger
}
func newImportResolver(r io.Reader, inPath string, fs afero.Fs, logger *loggers.Logger) *importResolver {
return &importResolver{
r: r,
inPath: inPath,
fs: fs, logger: logger,
linemap: make(map[int]fileOffset), contentSeen: make(map[string]bool),
}
}
func (imp *importResolver) contentHash(filename string) ([]byte, string) {
b, err := afero.ReadFile(imp.fs, filename)
if err != nil {
return nil, ""
}
h := sha256.New()
h.Write(b)
return b, hex.EncodeToString(h.Sum(nil))
}
func (imp *importResolver) importRecursive(
lineNum int,
content string,
inPath string) (int, string, error) {
basePath := path.Dir(inPath)
var replacements []string
lines := strings.Split(content, "\n")
trackLine := func(i, offset int, line string) {
// TODO(bep) this is not very efficient.
imp.linemap[i+lineNum] = fileOffset{Filename: inPath, Offset: offset}
}
i := 0
for offset, line := range lines {
i++
line = strings.TrimSpace(line)
if !imp.shouldImport(line) {
trackLine(i, offset, line)
} else {
i--
path := strings.Trim(strings.TrimPrefix(line, importIdentifier), " \"';")
filename := filepath.Join(basePath, path)
importContent, hash := imp.contentHash(filename)
if importContent == nil {
trackLine(i, offset, "ERROR")
imp.logger.WARN.Printf("postcss: Failed to resolve CSS @import in %q for path %q", inPath, filename)
continue
}
if imp.contentSeen[hash] {
i++
// Just replace the line with an empty string.
replacements = append(replacements, []string{line, ""}...)
trackLine(i, offset, "IMPORT")
continue
}
imp.contentSeen[hash] = true
// Handle recursive imports.
l, nested, err := imp.importRecursive(i+lineNum, string(importContent), filepath.ToSlash(filename))
if err != nil {
return 0, "", err
}
trackLine(i, offset, line)
i += l
importContent = []byte(nested)
replacements = append(replacements, []string{line, string(importContent)}...)
}
}
if len(replacements) > 0 {
repl := strings.NewReplacer(replacements...)
content = repl.Replace(content)
}
return i, content, nil
}
func (imp *importResolver) resolve() (io.Reader, error) {
const importIdentifier = "@import"
content, err := ioutil.ReadAll(imp.r)
if err != nil {
return nil, err
}
contents := string(content)
_, newContent, err := imp.importRecursive(0, contents, imp.inPath)
if err != nil {
return nil, err
}
return strings.NewReader(newContent), nil
}
// See https://www.w3schools.com/cssref/pr_import_rule.asp
// We currently only support simple file imports, no urls, no media queries.
// So this is OK:
// @import "navigation.css";
// This is not:
// @import url("navigation.css");
// @import "mobstyle.css" screen and (max-width: 768px);
func (imp *importResolver) shouldImport(s string) bool {
if !strings.HasPrefix(s, importIdentifier) {
return false
}
if strings.Contains(s, "url(") {
return false
}
return shouldImportRe.MatchString(s)
}
func (imp *importResolver) toFileError(output string) error {
inErr := errors.New(strings.TrimSpace(output))
match := cssSyntaxErrorRe.FindStringSubmatch(output)
if match == nil {
return inErr
}
lineNum, err := strconv.Atoi(match[1])
if err != nil {
return inErr
}
file, ok := imp.linemap[lineNum]
if !ok {
return inErr
}
fi, err := imp.fs.Stat(file.Filename)
if err != nil {
return inErr
}
realFilename := fi.(hugofs.FileMetaInfo).Meta().Filename()
ferr := herrors.NewFileError("css", -1, file.Offset+1, 1, inErr)
werr, ok := herrors.WithFileContextForFile(ferr, realFilename, file.Filename, imp.fs, herrors.SimpleLineMatcher)
if !ok {
return ferr
}
return werr
}