frontend: Rework asset generation

This commit reworks frontend asset generation to not need manually
written html files, but instead generate them automatically.

pkg/fsx/filter.go

@@ -1,94 +0,0 @@
-package fsx
-
-import (
-	"io/fs"
-	"path/filepath"
-
-	"github.com/tkw1536/goprogram/lib/collection"
-)
-
-// Censor returns a new filesystem censors files for which the censor function returns true.
-//
-// A censored file cannot be opened by the filesystem and return [fs.ErrNotExist].
-// Hard and Soft Links pointing to the file might still read it.
-func Censor(fsys fs.FS, censor func(name string) bool) fs.FS {
-	return &censorFS{
-		fsys:   fsys,
-		censor: censor,
-	}
-}
-
-type censorFS struct {
-	censor func(path string) bool
-	fsys   fs.FS
-}
-
-func (cf *censorFS) Sub(path string) (fs.FS, error) {
-	sub, err := fs.Sub(cf.fsys, path)
-	if err != nil {
-		return nil, err
-	}
-	return &censorFS{
-		censor: func(name string) bool {
-			return cf.censor(filepath.Join(path, name))
-		},
-		fsys: sub,
-	}, nil
-}
-
-func (ef *censorFS) Open(name string) (fs.File, error) {
-	if ef.censor(name) {
-		return nil, fs.ErrNotExist
-	}
-
-	file, err := ef.fsys.Open(name)
-
-	// we need to also censor the ReadDir function of the returned file
-	// this is to prevent the file from appearing in directory listings.
-	if rdf, ok := file.(fs.ReadDirFile); ok {
-		return &censorFSFile{
-			ReadDirFile: rdf,
-
-			name:   name,
-			censor: ef,
-		}, err
-	}
-	return file, err
-}
-
-type censorFSFile struct {
-	fs.ReadDirFile
-
-	name   string
-	censor *censorFS
-}
-
-func (f *censorFSFile) ReadDir(n int) ([]fs.DirEntry, error) {
-	entries, err := f.ReadDirFile.ReadDir(n)
-	return f.censor.handleReadDir(f.name, entries, err)
-}
-
-func (ef *censorFS) ReadDir(name string) ([]fs.DirEntry, error) {
-	if ef.censor(name) {
-		return nil, fs.ErrNotExist
-	}
-
-	// censor ReadDir() entries too
-	entries, err := fs.ReadDir(ef.fsys, name)
-	return ef.handleReadDir(name, entries, err)
-}
-
-// handleReadDir censors a ReadDir call
-func (ef *censorFS) handleReadDir(base string, entries []fs.DirEntry, err error) ([]fs.DirEntry, error) {
-	entries = collection.Filter(entries, func(entry fs.DirEntry) bool {
-		return !ef.censor(filepath.Join(base, entry.Name()))
-	})
-	return entries, err
-}
-
-func (ef *censorFS) ReadFile(name string) ([]byte, error) {
-	if ef.censor(name) {
-		return nil, fs.ErrNotExist
-	}
-	return fs.ReadFile(ef.fsys, name)
-}