object/store/internal/digest: Add docs, errors, record, result

Committing as I re-review

4 files changed, 128 insertions, 0 deletions

diff --git a/object/store/packed/internal/ingest/doc.go b/object/store/packed/internal/ingest/doc.go
new file mode 100644
index 00000000..67be037b
--- /dev/null
+++ b/object/store/packed/internal/ingest/doc.go
@@ -0,0 +1,11 @@
+// Package ingest writes one incoming pack stream
+// into an objects/pack directory
+// as a finalized pack, index, and reverse index.
+//
+// WritePack streams the pack to a temporary file
+// while scanning its entries,
+// resolves every delta against in-pack bases,
+// optionally completes thin packs from an external base reader,
+// and publishes the artifacts under content-addressed names
+// derived from the pack trailer hash.
+package ingest
diff --git a/object/store/packed/internal/ingest/errors.go b/object/store/packed/internal/ingest/errors.go
new file mode 100644
index 00000000..e268182e
--- /dev/null
+++ b/object/store/packed/internal/ingest/errors.go
@@ -0,0 +1,36 @@
+package ingest
+
+import (
+	"errors"
+	"fmt"
+
+	"lindenii.org/go/furgit/object/id"
+)
+
+// ErrMalformedPack reports that
+// the incoming pack stream is truncated,
+// inconsistent, or otherwise unparseable.
+var ErrMalformedPack = errors.New("object/store/packed/internal/ingest: malformed pack")
+
+// ErrThinPackNotPermitted reports that
+// the incoming pack is thin,
+// referencing bases not contained within it,
+// but no external base reader was supplied to complete it.
+var ErrThinPackNotPermitted = errors.New("object/store/packed/internal/ingest: thin pack not permitted: no thin base supplied")
+
+// ThinBasesMissingError reports that
+// an incoming thin pack references base objects
+// that the supplied thin base reader does not contain,
+// so the pack cannot be completed.
+type ThinBasesMissingError struct {
+	// OIDs holds the missing base object IDs, sorted.
+	OIDs []id.ObjectID
+}
+
+// Error implements error.
+func (e *ThinBasesMissingError) Error() string {
+	return fmt.Sprintf(
+		"object/store/packed/internal/ingest: thin pack references %d missing base objects",
+		len(e.OIDs),
+	)
+}
diff --git a/object/store/packed/internal/ingest/record.go b/object/store/packed/internal/ingest/record.go
new file mode 100644
index 00000000..460365fd
--- /dev/null
+++ b/object/store/packed/internal/ingest/record.go
@@ -0,0 +1,55 @@
+package ingest
+
+import (
+	"lindenii.org/go/furgit/internal/format/packfile"
+	"lindenii.org/go/furgit/object/id"
+)
+
+// record is the scanned metadata for one packed entry,
+// completed in place as deltas are resolved.
+//
+// Records are appended in pack-offset order,
+// so a record's index in the slice is also its pack order.
+type record struct {
+	// offset is the entry's start offset in the pack.
+	offset uint64
+
+	// headerLen is the entry header length in bytes,
+	// so the zlib payload begins at offset+headerLen.
+	headerLen uint64
+
+	// packedLen is the total on-disk entry length in bytes,
+	// covering the header and the compressed payload.
+	packedLen uint64
+
+	// crc32 is the CRC32 of the entry's packed bytes.
+	crc32 uint32
+
+	// packedType is the entry type as encoded in the pack.
+	packedType packfile.EntryType
+
+	// declaredSize is the declared inflated payload size.
+	declaredSize uint64
+
+	// baseOffset is the base entry offset for an ofs-delta.
+	baseOffset uint64
+
+	// baseOID is the base object ID for a ref-delta.
+	baseOID id.ObjectID
+
+	// objectType is the resolved object type,
+	// meaningful once resolved is true.
+	objectType packfile.EntryType
+
+	// oid is the resolved object ID,
+	// meaningful once resolved is true.
+	oid id.ObjectID
+
+	// resolved reports whether oid and objectType are final.
+	resolved bool
+}
+
+// dataOffset returns the entry's compressed payload start offset.
+func (record *record) dataOffset() uint64 {
+	return record.offset + record.headerLen
+}
diff --git a/object/store/packed/internal/ingest/result.go b/object/store/packed/internal/ingest/result.go
new file mode 100644
index 00000000..0ae5593a
--- /dev/null
+++ b/object/store/packed/internal/ingest/result.go
@@ -0,0 +1,26 @@
+package ingest
+
+import "lindenii.org/go/furgit/object/id"
+
+// Result describes one finalized pack write.
+type Result struct {
+	// PackName is the destination-relative name of the written pack.
+	PackName string
+
+	// IdxName is the destination-relative name of the written index.
+	IdxName string
+
+	// RevName is the destination-relative name of the written reverse index.
+	RevName string
+
+	// PackHash is the pack trailer hash
+	// shared by the pack, index, and reverse index.
+	PackHash id.ObjectID
+
+	// ObjectCount is the number of objects in the finalized pack,
+	// including any bases appended during thin completion.
+	ObjectCount uint32
+
+	// ThinFixed reports whether thin completion appended local bases.
+	ThinFixed bool
+}