fup: move hashfs into its own package.

We need to depend on its API for fuphttp, so it's better if it's a separate
package to avoid embedding things we don't need.

In general it's probably a good idea to separate the logic from the embedded
content...

web/fup/fupstatic/fupstatic.go

@@ -7,12 +7,14 @@ package fupstatic
 import (
 	"embed"
 	"io/fs"
+
+	"hg.lukegb.com/lukegb/depot/web/fup/hashfs"
 )
 
 //go:embed css js
 var static embed.FS
 
-var Static fs.FS = newStaticFS(static)
+var Static *hashfs.FS = hashfs.New(static)
 
 //go:embed tmpl
 var templates embed.FS

web/fup/hashfs/hashfs.go

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: Apache-2.0
 
-package fupstatic
+package hashfs
 
 import (
 	"crypto/sha512"
@@ -23,7 +23,7 @@ func adaptError(err error, name string) error {
 	return err
 }
 
-type staticFS struct {
+type FS struct {
 	fs fs.ReadFileFS
 
 	// We need:
@@ -70,7 +70,7 @@ func (f *staticFSFile) Stat() (fs.FileInfo, error) {
 type staticFSDirFile struct {
 	fs.ReadDirFile
 	basePath string
-	s        *staticFS
+	s        *FS
 }
 
 func (f staticFSDirFile) ReadDir(n int) ([]fs.DirEntry, error) {
@@ -88,7 +88,7 @@ func (f staticFSDirFile) ReadDir(n int) ([]fs.DirEntry, error) {
 }
 
 // build computes the hashes needed to serve files.
-func (s *staticFS) build() error {
+func (s *FS) build() error {
 	toHashName := make(map[string]string)
 	toPlainName := make(map[string]string)
 	if err := fs.WalkDir(s.fs, ".", func(fpath string, d fs.DirEntry, err error) error {
@@ -129,13 +129,13 @@ func (s *staticFS) build() error {
 }
 
 // LookupHashedName looks up the filename for the given original name.
-func (s *staticFS) LookupHashedName(name string) (string, bool) {
+func (s *FS) LookupHashedName(name string) (string, bool) {
 	n, ok := s.toHashName[name]
 	return n, ok
 }
 
 // Open opens the named file.
-func (s *staticFS) Open(name string) (fs.File, error) {
+func (s *FS) Open(name string) (fs.File, error) {
 	fn, ok := s.toPlainName[name]
 	if !ok {
 		// Try opening it as a plain name.
@@ -152,7 +152,7 @@ func (s *staticFS) Open(name string) (fs.File, error) {
 }
 
 // ReadFile provides an optimised ReadFile implementation.
-func (s *staticFS) ReadFile(name string) ([]byte, error) {
+func (s *FS) ReadFile(name string) ([]byte, error) {
 	fn, ok := s.toPlainName[name]
 	if !ok {
 		// Try opening it as a plain name.
@@ -165,8 +165,8 @@ func (s *staticFS) ReadFile(name string) ([]byte, error) {
 	return f, nil
 }
 
-func newStaticFS(fs fs.ReadFileFS) *staticFS {
-	s := &staticFS{
+func New(fs fs.ReadFileFS) *FS {
+	s := &FS{
 		fs: fs,
 	}
 	if err := s.build(); err != nil {

web/fup/hashfs/hashfs_test.go

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: Apache-2.0
 
-package fupstatic
+package hashfs
 
 import (
 	"testing"
@@ -19,7 +19,7 @@ func TestHashingFS(t *testing.T) {
 		},
 	}
 
-	f := newStaticFS(baseFS)
+	f := New(baseFS)
 
 	tcs := []struct {
 		origName    string