1 files changed, 106 insertions, 0 deletions
diff --git a/format/packfile/ingest/scan.go b/format/packfile/ingest/scan.go
new file mode 100644
index 00000000..de4e993c
--- /dev/null
+++ b/format/packfile/ingest/scan.go
@@ -0,0 +1,106 @@
+package ingest
+
+import (
+	"fmt"
+
+	"codeberg.org/lindenii/furgit/internal/progress"
+	objectid "codeberg.org/lindenii/furgit/object/id"
+)
+
+// streamPackAndScan copies src into temp .pack while scanning packed entries.
+func streamPackAndScan(state *ingestState) error {
+	hashImpl, err := state.algo.New()
+	if err != nil {
+		return err
+	}
+
+	state.stream = newStreamScanner(
+		state.src,
+		state.packFile,
+		hashImpl,
+		state.algo.Size(),
+	)
+
+	writeProgressf(state, "validating pack header...\r")
+
+	err = seedStreamWithPackHeader(state)
+	if err != nil {
+		return err
+	}
+
+	writeProgressf(state, "validating pack header: done.\n")
+
+	state.records = make([]objectRecord, 0, state.objectCountHeader)
+	state.ofsDeltas = make([]ofsDeltaRef, 0, state.objectCountHeader)
+	state.refDeltas = make([]refDeltaRef, 0, state.objectCountHeader)
+
+	total := state.objectCountHeader
+	meter := progress.New(progress.Options{
+		Writer:     state.opts.Progress,
+		Flush:      state.opts.ProgressFlush,
+		Title:      "receiving objects",
+		Total:      uint64(total),
+		Throughput: true,
+	})
+
+	for i := range total {
+		nextOffset, err := scanOneEntry(state, state.stream.consumed)
+		if err != nil {
+			return err
+		}
+
+		if nextOffset != state.stream.consumed {
+			return fmt.Errorf("packfile/ingest: internal stream offset mismatch")
+		}
+
+		done := i + 1
+		meter.Set(uint64(done), state.stream.consumed)
+	}
+
+	meter.Stop("done")
+
+	err = state.stream.finishAndFlushTrailer(state.opts.RequireTrailingEOF)
+	if err != nil {
+		return err
+	}
+
+	if len(state.stream.packTrailer) != state.algo.Size() {
+		return fmt.Errorf("packfile/ingest: invalid trailer size")
+	}
+
+	packHash, err := objectid.FromBytes(state.algo, state.stream.packTrailer)
+	if err != nil {
+		return err
+	}
+
+	state.packHash = packHash
+
+	return state.stream.flush()
+}
+
+// seedStreamWithPackHeader writes the already-validated PACK header to output,
+// seeds the running pack hash, and advances stream offset accounting.
+func seedStreamWithPackHeader(state *ingestState) error {
+	written := 0
+	for written < len(state.packHeaderRaw) {
+		n, err := state.packFile.Write(state.packHeaderRaw[written:])
+		if err != nil {
+			return &DestinationWriteError{Op: fmt.Sprintf("write pack header: %v", err)}
+		}
+
+		if n == 0 {
+			return &DestinationWriteError{Op: "write pack header: short write"}
+		}
+
+		written += n
+	}
+
+	_, err := state.stream.hash.Write(state.packHeaderRaw[:])
+	if err != nil {
+		return err
+	}
+
+	state.stream.consumed = packHeaderSize
+
+	return nil
+}