json: Implement a bunch of streaming JSON encoding/decoding

2 files changed, 54 insertions, 0 deletions

diff --git a/lib/btrfs/btrfsitem/item_extentcsum.go b/lib/btrfs/btrfsitem/item_extentcsum.go
index b35d333..eedd044 100644
--- a/lib/btrfs/btrfsitem/item_extentcsum.go
+++ b/lib/btrfs/btrfsitem/item_extentcsum.go
@@ -5,7 +5,11 @@
 package btrfsitem
 
 import (
+	"encoding/hex"
 	"fmt"
+	"io"
+
+	"git.lukeshu.com/go/lowmemjson"
 
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfssum"
 )
@@ -43,3 +47,33 @@ func (o ExtentCSum) MarshalBinary() ([]byte, error) {
 	}
 	return dat, nil
 }
+
+var (
+	_ lowmemjson.Encodable = ExtentCSum{}
+)
+
+func (o ExtentCSum) EncodeJSON(w io.Writer) error {
+	if _, err := fmt.Fprintf(w, `{"ChecksumSize":%d,"Sums":[`, o.ChecksumSize); err != nil {
+		return err
+	}
+	for i, sum := range o.Sums {
+		if i > 0 {
+			if _, err := w.Write([]byte(",")); err != nil {
+				return err
+			}
+		}
+		if _, err := w.Write([]byte(`"`)); err != nil {
+			return err
+		}
+		if _, err := hex.NewEncoder(w).Write(sum[:o.ChecksumSize]); err != nil {
+			return err
+		}
+		if _, err := w.Write([]byte(`"`)); err != nil {
+			return err
+		}
+	}
+	if _, err := w.Write([]byte(`]}`)); err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/lib/btrfs/btrfssum/csum.go b/lib/btrfs/btrfssum/csum.go
index 8f9ac1a..c7c1f37 100644
--- a/lib/btrfs/btrfssum/csum.go
+++ b/lib/btrfs/btrfssum/csum.go
@@ -5,6 +5,7 @@
 package btrfssum
 
 import (
+	"encoding"
 	"encoding/binary"
 	"encoding/hex"
 	"fmt"
@@ -15,10 +16,29 @@ import (
 
 type CSum [0x20]byte
 
+var (
+	_ fmt.Stringer             = CSum{}
+	_ fmt.Formatter            = CSum{}
+	_ encoding.TextMarshaler   = CSum{}
+	_ encoding.TextUnmarshaler = (*CSum)(nil)
+)
+
 func (csum CSum) String() string {
 	return hex.EncodeToString(csum[:])
 }
 
+func (csum CSum) MarshalText() ([]byte, error) {
+	var ret [len(csum) * 2]byte
+	hex.Encode(ret[:], csum[:])
+	return ret[:], nil
+}
+
+func (csum *CSum) UnmarshalText(text []byte) error {
+	*csum = CSum{}
+	_, err := hex.Decode(csum[:], text)
+	return err
+}
+
 func (csum CSum) Fmt(typ CSumType) string {
 	return hex.EncodeToString(csum[:typ.Size()])
 }