Share immutable in-memory filesystems

internal/framework/llm/asset_registry.go

@@ -1,17 +1,15 @@
 package llm
 
 import (
-	"bytes"
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"
 	"io"
 	"io/fs"
 	"path"
-	"sort"
 	"strings"
-	"time"
 
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/readonlyfs"
 	"gitea.maximumdirect.net/eric/promptkit"
 )
 
@@ -223,7 +221,7 @@ func newAssetSource(fsys fs.FS, root string) (AssetSource, error) {
 }
 
 func flattenAssetSources(sources []AssetSource) (fs.FS, error) {
-	out := assetMapFS{}
+	out := make(map[string][]byte)
 	for _, source := range sources {
 		if err := fs.WalkDir(source.FS, source.Root, func(name string, entry fs.DirEntry, walkErr error) error {
 			if walkErr != nil {
@@ -247,13 +245,13 @@ func flattenAssetSources(sources []AssetSource) (fs.FS, error) {
 			if err != nil {
 				return err
 			}
-			out[rel] = append([]byte(nil), data...)
+			out[rel] = data
 			return nil
 		}); err != nil {
 			return nil, fmt.Errorf("walk asset root %s: %w", source.Root, err)
 		}
 	}
-	return out, nil
+	return readonlyfs.New(out)
 }
 
 func cleanAssetRoot(root string) (string, error) {
@@ -275,156 +273,3 @@ func cleanAssetPath(name string) (string, error) {
 	}
 	return cleaned, nil
 }
-
-type assetMapFS map[string][]byte
-
-func (m assetMapFS) Open(name string) (fs.File, error) {
-	cleaned, err := cleanOpenPath(name)
-	if err != nil {
-		return nil, &fs.PathError{Op: "open", Path: name, Err: err}
-	}
-	if data, ok := m[cleaned]; ok {
-		return &assetFile{
-			reader: bytes.NewReader(data),
-			info:   assetFileInfo{name: path.Base(cleaned), size: int64(len(data))},
-		}, nil
-	}
-	entries := m.dirEntries(cleaned)
-	if entries != nil {
-		return &assetDir{name: path.Base(cleaned), entries: entries}, nil
-	}
-	return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrNotExist}
-}
-
-func (m assetMapFS) ReadFile(name string) ([]byte, error) {
-	cleaned, err := cleanOpenPath(name)
-	if err != nil {
-		return nil, &fs.PathError{Op: "readfile", Path: name, Err: err}
-	}
-	data, ok := m[cleaned]
-	if !ok {
-		return nil, &fs.PathError{Op: "readfile", Path: name, Err: fs.ErrNotExist}
-	}
-	return append([]byte(nil), data...), nil
-}
-
-func (m assetMapFS) ReadDir(name string) ([]fs.DirEntry, error) {
-	cleaned, err := cleanOpenPath(name)
-	if err != nil {
-		return nil, &fs.PathError{Op: "readdir", Path: name, Err: err}
-	}
-	entries := m.dirEntries(cleaned)
-	if entries == nil {
-		return nil, &fs.PathError{Op: "readdir", Path: name, Err: fs.ErrNotExist}
-	}
-	return entries, nil
-}
-
-func (m assetMapFS) dirEntries(dir string) []fs.DirEntry {
-	children := map[string]assetDirEntry{}
-	prefix := ""
-	if dir != "." {
-		prefix = dir + "/"
-	}
-	for name, data := range m {
-		if !strings.HasPrefix(name, prefix) {
-			continue
-		}
-		rest := strings.TrimPrefix(name, prefix)
-		if rest == "" {
-			continue
-		}
-		childName, _, hasSlash := strings.Cut(rest, "/")
-		entry := assetDirEntry{name: childName, dir: hasSlash}
-		if !hasSlash {
-			entry.size = int64(len(data))
-		}
-		children[childName] = entry
-	}
-	if len(children) == 0 {
-		if dir == "." {
-			return []fs.DirEntry{}
-		}
-		return nil
-	}
-	names := make([]string, 0, len(children))
-	for name := range children {
-		names = append(names, name)
-	}
-	sort.Strings(names)
-	entries := make([]fs.DirEntry, 0, len(names))
-	for _, name := range names {
-		entries = append(entries, children[name])
-	}
-	return entries
-}
-
-func cleanOpenPath(name string) (string, error) {
-	if name == "." {
-		return ".", nil
-	}
-	return cleanAssetPath(name)
-}
-
-type assetFile struct {
-	reader *bytes.Reader
-	info   assetFileInfo
-}
-
-func (f *assetFile) Stat() (fs.FileInfo, error) { return f.info, nil }
-func (f *assetFile) Read(p []byte) (int, error) { return f.reader.Read(p) }
-func (f *assetFile) Close() error               { return nil }
-
-type assetDir struct {
-	name    string
-	offset  int
-	entries []fs.DirEntry
-}
-
-func (d *assetDir) Stat() (fs.FileInfo, error) { return assetFileInfo{name: d.name, dir: true}, nil }
-func (d *assetDir) Read([]byte) (int, error)   { return 0, fmt.Errorf("cannot read directory") }
-func (d *assetDir) Close() error               { return nil }
-func (d *assetDir) ReadDir(n int) ([]fs.DirEntry, error) {
-	if d.offset >= len(d.entries) {
-		return nil, io.EOF
-	}
-	end := len(d.entries)
-	if n > 0 && d.offset+n < end {
-		end = d.offset + n
-	}
-	out := append([]fs.DirEntry(nil), d.entries[d.offset:end]...)
-	d.offset = end
-	return out, nil
-}
-
-type assetDirEntry struct {
-	name string
-	dir  bool
-	size int64
-}
-
-func (e assetDirEntry) Name() string      { return e.name }
-func (e assetDirEntry) IsDir() bool       { return e.dir }
-func (e assetDirEntry) Type() fs.FileMode { return e.InfoMode().Type() }
-func (e assetDirEntry) Info() (fs.FileInfo, error) {
-	return assetFileInfo{name: e.name, dir: e.dir, size: e.size}, nil
-}
-func (e assetDirEntry) InfoMode() fs.FileMode {
-	if e.dir {
-		return fs.ModeDir | 0o555
-	}
-	return 0o444
-}
-
-type assetFileInfo struct {
-	name string
-	dir  bool
-	size int64
-}
-
-func (i assetFileInfo) Name() string       { return i.name }
-func (i assetFileInfo) Size() int64        { return i.size }
-func (i assetFileInfo) Mode() fs.FileMode  { return assetDirEntry{dir: i.dir}.InfoMode() }
-func (i assetFileInfo) ModTime() time.Time { return time.Time{} }
-func (i assetFileInfo) IsDir() bool        { return i.dir }
-func (i assetFileInfo) Sys() any           { return nil }