From 6e104326f81ec59ece1817988af41b70e4f4cd15 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Sun, 23 Jul 2023 00:18:47 -0600
Subject: rebuildmappings scan: Include the device size and superblock

---
 cmd/btrfs-rec/inspect/rebuildmappings/scan.go | 13 +++++---
 lib/jsonutil/binstruct.go                     | 48 +++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 5 deletions(-)
 create mode 100644 lib/jsonutil/binstruct.go

diff --git a/cmd/btrfs-rec/inspect/rebuildmappings/scan.go b/cmd/btrfs-rec/inspect/rebuildmappings/scan.go
index d96005e..9454ca0 100644
--- a/cmd/btrfs-rec/inspect/rebuildmappings/scan.go
+++ b/cmd/btrfs-rec/inspect/rebuildmappings/scan.go
@@ -19,6 +19,7 @@ import (
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfsutil"
 	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
+	"git.lukeshu.com/btrfs-progs-ng/lib/jsonutil"
 	"git.lukeshu.com/btrfs-progs-ng/lib/textui"
 )
 
@@ -27,6 +28,8 @@ import (
 type ScanDevicesResult = map[btrfsvol.DeviceID]ScanOneDeviceResult
 
 type ScanOneDeviceResult struct {
+	Size             btrfsvol.PhysicalAddr
+	Superblock       jsonutil.Binary[btrfstree.Superblock]
 	Checksums        btrfssum.SumRun[btrfsvol.PhysicalAddr]
 	FoundNodes       map[btrfsvol.LogicalAddr][]btrfsvol.PhysicalAddr
 	FoundChunks      []FoundChunk
@@ -72,7 +75,6 @@ func ScanOneDevice(ctx context.Context, dev *btrfs.Device) (ScanOneDeviceResult,
 // scanner implementation //////////////////////////////////////////////////////
 
 type deviceScanner struct {
-	alg    btrfssum.CSumType
 	sums   strings.Builder
 	result ScanOneDeviceResult
 }
@@ -104,17 +106,18 @@ func (scanner *deviceScanner) ScanStats() scanStats {
 	}
 }
 
-func newDeviceScanner(_ context.Context, sb btrfstree.Superblock, _ btrfsvol.PhysicalAddr, numSectors int) btrfsutil.DeviceScanner[scanStats, ScanOneDeviceResult] {
+func newDeviceScanner(_ context.Context, sb btrfstree.Superblock, numBytes btrfsvol.PhysicalAddr, numSectors int) btrfsutil.DeviceScanner[scanStats, ScanOneDeviceResult] {
 	scanner := new(deviceScanner)
-	scanner.alg = sb.ChecksumType
+	scanner.result.Size = numBytes
+	scanner.result.Superblock.Val = sb
 	scanner.result.FoundNodes = make(map[btrfsvol.LogicalAddr][]btrfsvol.PhysicalAddr)
-	scanner.result.Checksums.ChecksumSize = scanner.alg.Size()
+	scanner.result.Checksums.ChecksumSize = scanner.result.Superblock.Val.ChecksumType.Size()
 	scanner.sums.Grow(scanner.result.Checksums.ChecksumSize * numSectors)
 	return scanner
 }
 
 func (scanner *deviceScanner) ScanSector(_ context.Context, dev *btrfs.Device, paddr btrfsvol.PhysicalAddr) error {
-	sum, err := btrfs.ChecksumPhysical(dev, scanner.alg, paddr)
+	sum, err := btrfs.ChecksumPhysical(dev, scanner.result.Superblock.Val.ChecksumType, paddr)
 	if err != nil {
 		return err
 	}
diff --git a/lib/jsonutil/binstruct.go b/lib/jsonutil/binstruct.go
new file mode 100644
index 0000000..7f4bd3f
--- /dev/null
+++ b/lib/jsonutil/binstruct.go
@@ -0,0 +1,48 @@
+// Copyright (C) 2023  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package jsonutil
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+
+	"git.lukeshu.com/go/lowmemjson"
+
+	"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
+	"git.lukeshu.com/btrfs-progs-ng/lib/textui"
+)
+
+type Binary[T any] struct {
+	Val T
+}
+
+var (
+	_ lowmemjson.Encodable = Binary[int]{}
+	_ lowmemjson.Decodable = (*Binary[int])(nil)
+)
+
+func (o Binary[T]) EncodeJSON(w io.Writer) error {
+	bs, err := binstruct.Marshal(o.Val)
+	if err != nil {
+		return err
+	}
+	return EncodeSplitHexString(w, bs, textui.Tunable(80))
+}
+
+func (o *Binary[T]) DecodeJSON(r io.RuneScanner) error {
+	var buf bytes.Buffer
+	if err := DecodeSplitHexString(r, &buf); err != nil {
+		return err
+	}
+	n, err := binstruct.Unmarshal(buf.Bytes(), &o.Val)
+	if err != nil {
+		return err
+	}
+	if n < buf.Len() {
+		return fmt.Errorf("%d bytes of garbage after value", n-buf.Len())
+	}
+	return nil
+}
-- 
cgit v1.1-4-g5e80