Merge remote-tracking branch 'upstream/dev' into theme_switcher

internal/glance/embed.go

@@ -1,13 +1,19 @@
 package glance
 
 import (
+	"bytes"
 	"crypto/md5"
 	"embed"
 	"encoding/hex"
+	"errors"
+	"fmt"
 	"io"
 	"io/fs"
 	"log"
+	"path/filepath"
+	"regexp"
 	"strconv"
+	"strings"
 	"time"
 )
 
@@ -20,6 +26,19 @@ var _templateFS embed.FS
 var staticFS, _ = fs.Sub(_staticFS, "static")
 var templateFS, _ = fs.Sub(_templateFS, "templates")
 
+func readAllFromStaticFS(path string) ([]byte, error) {
+	// For some reason fs.FS only works with forward slashes, so in case we're
+	// running on Windows or pass paths with backslashes we need to replace them.
+	path = strings.ReplaceAll(path, "\\", "/")
+
+	file, err := staticFS.Open(path)
+	if err != nil {
+		return nil, err
+	}
+
+	return io.ReadAll(file)
+}
+
 var staticFSHash = func() string {
 	hash, err := computeFSHash(staticFS)
 	if err != nil {
@@ -60,3 +79,74 @@ func computeFSHash(files fs.FS) (string, error) {
 
 	return hex.EncodeToString(hash.Sum(nil))[:10], nil
 }
+
+var cssImportPattern = regexp.MustCompile(`(?m)^@import "(.*?)";$`)
+var cssSingleLineCommentPattern = regexp.MustCompile(`(?m)^\s*\/\*.*?\*\/$`)
+var whitespaceAtBeginningOfLinePattern = regexp.MustCompile(`(?m)^\s+`)
+
+// Yes, we bundle at runtime, give comptime pls
+var bundledCSSContents = func() []byte {
+	const mainFilePath = "css/main.css"
+
+	var recursiveParseImports func(path string, depth int) ([]byte, error)
+	recursiveParseImports = func(path string, depth int) ([]byte, error) {
+		if depth > 20 {
+			return nil, errors.New("maximum import depth reached, is one of your imports circular?")
+		}
+
+		mainFileContents, err := readAllFromStaticFS(path)
+		if err != nil {
+			return nil, err
+		}
+
+		// Normalize line endings, otherwise the \r's make the regex not match
+		mainFileContents = bytes.ReplaceAll(mainFileContents, []byte("\r\n"), []byte("\n"))
+
+		mainFileDir := filepath.Dir(path)
+		var importLastErr error
+
+		parsed := cssImportPattern.ReplaceAllFunc(mainFileContents, func(match []byte) []byte {
+			if importLastErr != nil {
+				return nil
+			}
+
+			matches := cssImportPattern.FindSubmatch(match)
+			if len(matches) != 2 {
+				importLastErr = fmt.Errorf(
+					"import didn't return expected number of capture groups: %s, expected 2, got %d",
+					match, len(matches),
+				)
+				return nil
+			}
+
+			importFilePath := filepath.Join(mainFileDir, string(matches[1]))
+			importContents, err := recursiveParseImports(importFilePath, depth+1)
+			if err != nil {
+				importLastErr = err
+				return nil
+			}
+
+			return importContents
+		})
+
+		if importLastErr != nil {
+			return nil, importLastErr
+		}
+
+		return parsed, nil
+	}
+
+	contents, err := recursiveParseImports(mainFilePath, 0)
+	if err != nil {
+		panic(fmt.Sprintf("building CSS bundle: %v", err))
+	}
+
+	// We could strip a bunch more unnecessary characters, but the biggest
+	// win comes from removing the whitespace at the beginning of lines
+	// since that's at least 4 bytes per property, which yielded a ~20% reduction.
+	contents = cssSingleLineCommentPattern.ReplaceAll(contents, nil)
+	contents = whitespaceAtBeginningOfLinePattern.ReplaceAll(contents, nil)
+	contents = bytes.ReplaceAll(contents, []byte("\n"), []byte(""))
+
+	return contents
+}()