1 files changed, 100 insertions, 0 deletions
diff --git a/format/packfile/ingest/thin_fix.go b/format/packfile/ingest/thin_fix.go
new file mode 100644
index 00000000..83e5572a
--- /dev/null
+++ b/format/packfile/ingest/thin_fix.go
@@ -0,0 +1,100 @@
+package ingest
+
+import (
+	"errors"
+	"fmt"
+
+	"codeberg.org/lindenii/furgit/internal/intconv"
+	"codeberg.org/lindenii/furgit/internal/progress"
+	objectstorer "codeberg.org/lindenii/furgit/object/storer"
+)
+
+// maybeFixThin appends missing bases and rewrites pack header/trailer when needed.
+func maybeFixThin(state *ingestState) error {
+	if len(state.unresolvedRefDeltas) == 0 {
+		return nil
+	}
+
+	writeProgressf(
+		state,
+		"fixing thin pack: %d unresolved bases\r",
+		len(state.unresolvedRefDeltas),
+	)
+
+	if !state.opts.FixThin {
+		return &ThinPackUnresolvedError{Count: len(state.unresolvedRefDeltas)}
+	}
+
+	if state.opts.Base == nil {
+		return &ThinPackUnresolvedError{Count: len(state.unresolvedRefDeltas)}
+	}
+
+	hashSize := int64(state.algo.Size())
+
+	info, err := state.packFile.Stat()
+	if err != nil {
+		return err
+	}
+
+	size := info.Size()
+	if size < hashSize {
+		return fmt.Errorf("packfile/ingest: pack too short to trim trailer")
+	}
+
+	newEnd := size - hashSize
+
+	err = state.packFile.Truncate(newEnd)
+	if err != nil {
+		return err
+	}
+
+	consumed, err := intconv.Int64ToUint64(newEnd)
+	if err != nil {
+		return err
+	}
+
+	state.stream.consumed = consumed
+
+	baseIDs := unresolvedThinBaseIDs(state)
+
+	total := len(baseIDs)
+	meter := progress.New(progress.Options{
+		Writer: state.opts.Progress,
+		Flush:  state.opts.ProgressFlush,
+		Title:  "fixing thin pack",
+		Total:  uint64(total),
+	})
+	meter.Set(0, 0)
+
+	var appended uint64
+
+	for _, id := range baseIDs {
+		ty, content, err := state.opts.Base.ReadBytesContent(id)
+		if err != nil {
+			if errors.Is(err, objectstorer.ErrObjectNotFound) {
+				continue
+			}
+
+			return fmt.Errorf("packfile/ingest: read thin base %s: %w", id, err)
+		}
+
+		_, err = appendBaseObject(state, id, ty, content)
+		if err != nil {
+			return err
+		}
+
+		state.thinFixed = true
+
+		appended++
+		meter.Set(appended, 0)
+	}
+
+	err = rewritePackHeaderAndTrailer(state)
+	if err != nil {
+		return err
+	}
+
+	meter.Stop(fmt.Sprintf("appended %d/%d, done", appended, total))
+
+	return nil
+}