X-Git-Url: https://git.giacomolli.uk/onechat/blobdiff_plain/feda522eba3e2a27c91741c77d0d01f1840c0004..97729fc59a2fbd73e3f8a424cae4c825f5ba885b:/journal.go?ds=inline

diff --git a/journal.go b/journal.go
index ef49c6e..cda9375 100644
--- a/journal.go
+++ b/journal.go
@@ -133,7 +133,9 @@ func (j *journal) Close() error {
 }
 
 // Scan gives each line of the day files from place on to add, with its
-// position, oldest day first. The zero position starts at the first line.
+// position, oldest day first. The zero position starts at the first line. A
+// crash during a write can leave a part of a line at the end of the last day
+// file. Its write never returned, so Scan cuts it off.
 func (j *journal) Scan(ctx context.Context, place position, add func([]byte, position) error) error {
 	paths, err := filepath.Glob(filepath.Join(j.dir, "*.jsonl"))
 	if err != nil {
@@ -141,7 +143,7 @@ func (j *journal) Scan(ctx context.Context, place position, add func([]byte, pos
 	}
 
 	slices.Sort(paths)
-	for _, path := range paths {
+	for n, path := range paths {
 		day, err := dayNumber(strings.TrimSuffix(filepath.Base(path), ".jsonl"))
 		if err != nil {
 			return err
@@ -156,7 +158,7 @@ func (j *journal) Scan(ctx context.Context, place position, add func([]byte, pos
 			offset = place.offset
 		}
 
-		err = scanFile(ctx, path, day, offset, add)
+		err = scanFile(ctx, path, day, offset, n == len(paths)-1, add)
 		if err != nil {
 			return err
 		}
@@ -165,8 +167,9 @@ func (j *journal) Scan(ctx context.Context, place position, add func([]byte, pos
 	return nil
 }
 
-// scanFile gives each line of the day file at path from offset on to add.
-func scanFile(ctx context.Context, path string, day uint32, offset uint64, add func([]byte, position) error) (err error) {
+// scanFile gives each line of the day file at path from offset on to add. In
+// the last day file, it cuts a part of a line at the end.
+func scanFile(ctx context.Context, path string, day uint32, offset uint64, last bool, add func([]byte, position) error) (err error) {
 	file, err := os.Open(path)
 	if err != nil {
 		return fmt.Errorf("open day file: %w", err)
@@ -192,6 +195,10 @@ func scanFile(ctx context.Context, path string, day uint32, offset uint64, add f
 			return nil
 		}
 
+		if errors.Is(err, io.EOF) && last {
+			return cutFile(path, offset)
+		}
+
 		if errors.Is(err, io.EOF) {
 			return fmt.Errorf("%s ends in an incomplete line at %d", filepath.Base(path), offset)
 		}
@@ -215,6 +222,16 @@ func scanFile(ctx context.Context, path string, day uint32, offset uint64, add f
 	}
 }
 
+// cutFile cuts the file at path to size bytes.
+func cutFile(path string, size uint64) error {
+	err := os.Truncate(path, int64(size))
+	if err != nil {
+		return fmt.Errorf("cut incomplete line: %w", err)
+	}
+
+	return nil
+}
+
 // dayNumber returns the day YYYY-MM-DD as the number YYYYMMDD.
 func dayNumber(day string) (uint32, error) {
 	number, err := strconv.ParseUint(strings.ReplaceAll(day, "-", ""), 10, 32)