Linked list is cool, but have you heard of array

1 files changed, 45 insertions, 49 deletions

diff --git a/roseh.moe.go b/roseh.moe.go
index 5600a75..33122d2 100644
--- a/roseh.moe.go
+++ b/roseh.moe.go
@@ -18,6 +18,7 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -407,20 +408,20 @@ func listNotes(req *api.ListNotesRequest) (*api.ListNotesResponse, error) {
 	return &api.ListNotesResponse{Notes: names}, nil
 }
 
-func readLinkedList(w io.Writer, next []byte, key cryptoutil.EncryptionKey, name string) error {
+func dumpFile(w io.Writer, key cryptoutil.EncryptionKey, name string) error {
 	f, err := os.Open(name)
 	if err != nil {
 		return err
 	}
 	defer f.Close()
-	reader := key.NewReader(f, []byte("chunks/"+filepath.Base(name)))
-	if _, err := io.ReadFull(reader, next); err != nil {
-		return err
-	}
-	_, err = io.Copy(w, reader)
+	_, err = io.Copy(w, key.NewReader(f, []byte("chunks/"+filepath.Base(name))))
 	return err
 }
 
+func chunkName(prefix string, i int64) string {
+	return fmt.Sprintf("%s%013s", prefix, strconv.FormatUint(uint64(i), 36))
+}
+
 var (
 	//go:embed wordlist.txt
 	wordListString string
@@ -429,8 +430,8 @@ var (
 
 func createNote(req *api.CreateNoteRequest) (*api.CreateNoteResponse, error) {
 	type continuationToken struct {
-		Head string
-		Tail []byte
+		Prefix string
+		I      int64
 	}
 
 	encryptionKeyMu.Lock()
@@ -439,10 +440,8 @@ func createNote(req *api.CreateNoteRequest) (*api.CreateNoteResponse, error) {
 	if key == nil {
 		return nil, fmt.Errorf("%w: need login", api.PermissionDenied)
 	}
-	var (
-		contToken continuationToken
-		f         *os.File
-	)
+
+	var contToken continuationToken
 	if len(req.ContinuationToken) > 0 {
 		msg, ok := secretKey.Verify(req.ContinuationToken, "continuation-token")
 		if !ok {
@@ -451,8 +450,19 @@ func createNote(req *api.CreateNoteRequest) (*api.CreateNoteResponse, error) {
 		if err := gob.NewDecoder(bytes.NewReader(msg)).Decode(&contToken); err != nil {
 			return nil, fmt.Errorf("bad continuation token")
 		}
-		var err error
-		f, err = os.OpenFile(*notepadDir+"/chunks/"+base64.RawURLEncoding.EncodeToString(contToken.Tail), os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0600)
+	} else {
+		token := make([]byte, 64)
+		rand.Read(token)
+		contToken.Prefix = base64.RawURLEncoding.EncodeToString(token)
+		contToken.I = 0
+	}
+
+	if req.More {
+		if err := os.MkdirAll(*notepadDir+"/chunks", 0700); err != nil {
+			return nil, err
+		}
+		name := chunkName(contToken.Prefix, contToken.I)
+		f, err := os.OpenFile(*notepadDir+"/chunks/"+name, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0600)
 		if err != nil {
 			if errors.Is(err, os.ErrExist) {
 				return nil, fmt.Errorf("%w: continuation token expired", api.InvalidArgument)
@@ -460,39 +470,28 @@ func createNote(req *api.CreateNoteRequest) (*api.CreateNoteResponse, error) {
 			return nil, err
 		}
 		defer f.Close()
-	} else {
-		if err := os.MkdirAll(*notepadDir+"/chunks", 0700); err != nil {
+		if contToken.I > 0 {
+			_, err := os.Stat(*notepadDir + "/chunks/" + chunkName(contToken.Prefix, 0))
+			if err != nil {
+				if errors.Is(err, os.ErrNotExist) {
+					return nil, fmt.Errorf("%w: continuation token expired", api.InvalidArgument)
+				}
+				return nil, err
+			}
+		}
+		encryptingWriter := key.NewWriter(f, []byte("chunks/"+name))
+		if _, err := encryptingWriter.Write(req.Chunk); err != nil {
 			return nil, err
 		}
-		var err error
-		f, err = os.CreateTemp(*notepadDir+"/chunks", "head")
-		if err != nil {
+		if err := encryptingWriter.Close(); err != nil {
 			return nil, err
 		}
-		defer f.Close()
-	}
-	next := make([]byte, 64)
-	rand.Read(next)
-	encryptingWriter := key.NewWriter(f, []byte("chunks/"+filepath.Base(f.Name())))
-	if _, err := encryptingWriter.Write(next); err != nil {
-		return nil, err
-	}
-	if _, err := encryptingWriter.Write(req.Chunk); err != nil {
-		return nil, err
-	}
-	if err := encryptingWriter.Close(); err != nil {
-		return nil, err
-	}
-	if err := f.Close(); err != nil {
-		return nil, err
-	}
-	head := contToken.Head
-	if head == "" {
-		head = filepath.Base(f.Name())
-	}
-	if req.More {
+		if err := f.Close(); err != nil {
+			return nil, err
+		}
+		contToken.I++
 		buf := new(bytes.Buffer)
-		if err := gob.NewEncoder(buf).Encode(continuationToken{Head: head, Tail: next}); err != nil {
+		if err := gob.NewEncoder(buf).Encode(contToken); err != nil {
 			return nil, err
 		}
 		return &api.CreateNoteResponse{ContinuationToken: secretKey.Sign(buf.Bytes(), "continuation-token")}, nil
@@ -520,12 +519,9 @@ func createNote(req *api.CreateNoteRequest) (*api.CreateNoteResponse, error) {
 		defer finalNote.Close()
 		break
 	}
-	var chunks []string
 	writer := key.NewWriter(finalNote, []byte("notes/"+filepath.Base(finalNote.Name())))
-	tailBase64 := base64.RawURLEncoding.EncodeToString(next)
-	for chunk := head; chunk != tailBase64; chunk = base64.RawURLEncoding.EncodeToString(next) {
-		chunks = append(chunks, chunk)
-		if err := readLinkedList(writer, next, key, *notepadDir+"/chunks/"+chunk); err != nil {
+	for i := range contToken.I {
+		if err := dumpFile(writer, key, *notepadDir+"/chunks/"+chunkName(contToken.Prefix, i)); err != nil {
 			return nil, err
 		}
 	}
@@ -538,8 +534,8 @@ func createNote(req *api.CreateNoteRequest) (*api.CreateNoteResponse, error) {
 	if err := finalNote.Close(); err != nil {
 		return nil, err
 	}
-	for _, chunk := range chunks {
-		if err := os.Remove(*notepadDir + "/chunks/" + chunk); err != nil {
+	for i := range contToken.I {
+		if err := os.Remove(*notepadDir + "/chunks/" + chunkName(contToken.Prefix, i)); err != nil {
 			log.Printf("Warning: createNote: failed to delete chunk: %s", err)
 		}
 	}