object,store/packed{,/internal/ingest}: Move from format/packfile/ingest

1 files changed, 58 insertions, 0 deletions

diff --git a/object/store/packed/internal/ingest/write_empty.go b/object/store/packed/internal/ingest/write_empty.go
new file mode 100644
index 00000000..0d3401f0
--- /dev/null
+++ b/object/store/packed/internal/ingest/write_empty.go
@@ -0,0 +1,58 @@
+package ingest
+
+import (
+	"bytes"
+	"errors"
+	"io"
+
+	objectid "codeberg.org/lindenii/furgit/object/id"
+)
+
+func discardZeroObjectPack(
+	src io.Reader,
+	algo objectid.Algorithm,
+	opts Options,
+	headerRaw [packHeaderSize]byte,
+) (Result, error) {
+	hashImpl, err := algo.New()
+	if err != nil {
+		return Result{}, err
+	}
+
+	_, _ = hashImpl.Write(headerRaw[:])
+
+	trailer := make([]byte, algo.Size())
+
+	_, err = io.ReadFull(src, trailer)
+	if err != nil {
+		return Result{}, &PackTrailerMismatchError{}
+	}
+
+	computed := hashImpl.Sum(nil)
+	if !bytes.Equal(computed, trailer) {
+		return Result{}, &PackTrailerMismatchError{}
+	}
+
+	if opts.RequireTrailingEOF {
+		var probe [1]byte
+
+		n, err := src.Read(probe[:])
+		if n > 0 || err == nil {
+			return Result{}, errors.New("packfile/ingest: pack has trailing garbage")
+		}
+
+		if err != io.EOF {
+			return Result{}, err
+		}
+	}
+
+	packHash, err := objectid.FromBytes(algo, trailer)
+	if err != nil {
+		return Result{}, err
+	}
+
+	return Result{
+		PackHash:    packHash,
+		ObjectCount: 0,
+	}, nil
+}