Add css.TailwindCSS

Closes #12618
Closes #12620

resources/resource_transformers/cssjs/inline_imports.go

@@ -0,0 +1,247 @@
+// Copyright 2024 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 cssjs
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"path"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/gohugoio/hugo/common/herrors"
+	"github.com/gohugoio/hugo/common/loggers"
+	"github.com/gohugoio/hugo/common/text"
+	"github.com/gohugoio/hugo/hugofs"
+	"github.com/gohugoio/hugo/identity"
+	"github.com/spf13/afero"
+)
+
+const importIdentifier = "@import"
+
+var (
+	cssSyntaxErrorRe = regexp.MustCompile(`> (\d+) \|`)
+	shouldImportRe   = regexp.MustCompile(`^@import ["'](.*?)["'];?\s*(/\*.*\*/)?$`)
+)
+
+type fileOffset struct {
+	Filename string
+	Offset   int
+}
+
+type importResolver struct {
+	r      io.Reader
+	inPath string
+	opts   InlineImports
+
+	contentSeen       map[string]bool
+	dependencyManager identity.Manager
+	linemap           map[int]fileOffset
+	fs                afero.Fs
+	logger            loggers.Logger
+}
+
+func newImportResolver(r io.Reader, inPath string, opts InlineImports, fs afero.Fs, logger loggers.Logger, dependencyManager identity.Manager) *importResolver {
+	return &importResolver{
+		r:                 r,
+		dependencyManager: dependencyManager,
+		inPath:            inPath,
+		fs:                fs, logger: logger,
+		linemap: make(map[int]fileOffset), contentSeen: make(map[string]bool),
+		opts: opts,
+	}
+}
+
+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++
+		lineTrimmed := strings.TrimSpace(line)
+		column := strings.Index(line, lineTrimmed)
+		line = lineTrimmed
+
+		if !imp.shouldImport(line) {
+			trackLine(i, offset, line)
+		} else {
+			path := strings.Trim(strings.TrimPrefix(line, importIdentifier), " \"';")
+			filename := filepath.Join(basePath, path)
+			imp.dependencyManager.AddIdentity(identity.CleanStringIdentity(filename))
+			importContent, hash := imp.contentHash(filename)
+
+			if importContent == nil {
+				if imp.opts.SkipInlineImportsNotFound {
+					trackLine(i, offset, line)
+					continue
+				}
+				pos := text.Position{
+					Filename:     inPath,
+					LineNumber:   offset + 1,
+					ColumnNumber: column + 1,
+				}
+				return 0, "", herrors.NewFileErrorFromFileInPos(fmt.Errorf("failed to resolve CSS @import \"%s\"", filename), pos, imp.fs, nil)
+			}
+
+			i--
+
+			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) {
+	content, err := io.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
+	}
+
+	m := shouldImportRe.FindStringSubmatch(s)
+	if m == nil {
+		return false
+	}
+
+	if len(m) != 3 {
+		return false
+	}
+
+	if tailwindImportExclude(m[1]) {
+		return false
+	}
+
+	return true
+}
+
+func (imp *importResolver) toFileError(output string) error {
+	inErr := errors.New(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
+	}
+
+	meta := fi.(hugofs.FileMetaInfo).Meta()
+	realFilename := meta.Filename
+	f, err := meta.Open()
+	if err != nil {
+		return inErr
+	}
+	defer f.Close()
+
+	ferr := herrors.NewFileErrorFromName(inErr, realFilename)
+	pos := ferr.Position()
+	pos.LineNumber = file.Offset + 1
+	return ferr.UpdatePosition(pos).UpdateContent(f, nil)
+
+	// return herrors.NewFileErrorFromFile(inErr, file.Filename, realFilename, hugofs.Os, herrors.SimpleLineMatcher)
+}