1 files changed, 94 insertions, 0 deletions
diff --git a/object/store/loose/write_writer.go b/object/store/loose/write_writer.go
new file mode 100644
index 00000000..0d6b5b80
--- /dev/null
+++ b/object/store/loose/write_writer.go
@@ -0,0 +1,94 @@
+package loose
+
+import (
+	"errors"
+	"hash"
+	"os"
+
+	"codeberg.org/lindenii/furgit/internal/compress/zlib"
+)
+
+const tempObjectFilePrefix = "tmp_obj_"
+
+// streamWriter incrementally hashes and deflates an object into a temp file.
+// Finalize validates size accounting and atomically renames the temp file.
+type streamWriter struct {
+	// store owns path and root operations used by this write session.
+	store *Store
+	// file is the temporary destination file under objects/.
+	file *os.File
+	// zw compresses raw object bytes into file.
+	zw *zlib.Writer
+	// hash receives the same raw bytes used to compute the resulting object ID.
+	hash hash.Hash
+
+	// tmpRelPath is the relative path of file under the objects root.
+	tmpRelPath string
+
+	// fullMode selects full-object input ("type size\0content") as opposed to content-only input.
+	fullMode bool
+
+	// headerBuf accumulates header bytes while fullMode parses up to the first NUL.
+	headerBuf []byte
+	// headerDone reports whether the full-object header has been parsed.
+	headerDone bool
+	// expectedContentLeft tracks remaining declared content bytes.
+	expectedContentLeft int64
+
+	closed    bool
+	finalized bool
+}
+
+// newStreamWriter creates a stream writer with a temp file rooted in objects/.
+func (store *Store) newStreamWriter(fullMode bool) (*streamWriter, error) {
+	hashFn, err := store.algo.New()
+	if err != nil {
+		return nil, err
+	}
+
+	tmpRelPath, file, err := store.createTempObjectFile(".")
+	if err != nil {
+		return nil, err
+	}
+
+	return &streamWriter{
+		store:      store,
+		file:       file,
+		zw:         zlib.NewWriter(file),
+		hash:       hashFn,
+		tmpRelPath: tmpRelPath,
+		fullMode:   fullMode,
+		headerBuf:  make([]byte, 0, 64),
+	}, nil
+}
+
+// Write validates and writes raw bytes into the stream.
+// In full mode, it parses and enforces the streamed header-declared content size.
+func (writer *streamWriter) Write(src []byte) (int, error) {
+	if writer.finalized {
+		return 0, errors.New("objectstore/loose: write after finalize")
+	}
+
+	if writer.closed {
+		return 0, errors.New("objectstore/loose: write after close")
+	}
+
+	if writer.fullMode {
+		err := writer.acceptFull(src)
+		if err != nil {
+			return 0, err
+		}
+	} else {
+		err := writer.acceptContent(int64(len(src)))
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	err := writer.writeRawChunk(src)
+	if err != nil {
+		return 0, err
+	}
+
+	return len(src), nil
+}