From dde8e9e29636aff6a1041cf426f4e825dd11015f Mon Sep 17 00:00:00 2001
From: greatroar <61184462+greatroar@users.noreply.github.com>
Date: Fri, 27 May 2022 10:55:51 +0200
Subject: [PATCH] internal/restic: Custom ID.MarshalJSON
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This skips an allocation. internal/archiver benchmarks, Linux/amd64:

name                     old time/op    new time/op    delta
ArchiverSaveFileSmall-8    3.94ms ± 6%    3.91ms ± 6%    ~     (p=0.947 n=20+20)
ArchiverSaveFileLarge-8     304ms ± 3%     301ms ± 4%    ~     (p=0.265 n=18+18)

name                     old speed      new speed      delta
ArchiverSaveFileSmall-8  1.04MB/s ± 6%  1.05MB/s ± 6%    ~     (p=0.803 n=20+20)
ArchiverSaveFileLarge-8   142MB/s ± 3%   143MB/s ± 4%    ~     (p=0.421 n=18+19)

name                     old alloc/op   new alloc/op   delta
ArchiverSaveFileSmall-8    17.9MB ± 0%    17.9MB ± 0%  -0.01%  (p=0.000 n=19+19)
ArchiverSaveFileLarge-8     382MB ± 2%     382MB ± 1%    ~     (p=0.687 n=20+19)

name                     old allocs/op  new allocs/op  delta
ArchiverSaveFileSmall-8       540 ± 1%       528 ± 0%  -2.19%  (p=0.000 n=19+19)
ArchiverSaveFileLarge-8     1.93k ± 3%     1.79k ± 4%  -7.06%  (p=0.000 n=20+20)
---
 internal/restic/id.go | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/internal/restic/id.go b/internal/restic/id.go
index c098dbfb3..6d85ed68a 100644
--- a/internal/restic/id.go
+++ b/internal/restic/id.go
@@ -3,7 +3,6 @@ package restic
 import (
 	"crypto/rand"
 	"encoding/hex"
-	"encoding/json"
 	"fmt"
 	"io"
 
@@ -98,7 +97,13 @@ func (id ID) EqualString(other string) (bool, error) {
 
 // MarshalJSON returns the JSON encoding of id.
 func (id ID) MarshalJSON() ([]byte, error) {
-	return json.Marshal(id.String())
+	buf := make([]byte, 2+hex.EncodedLen(len(id)))
+
+	buf[0] = '"'
+	hex.Encode(buf[1:], id[:])
+	buf[len(buf)-1] = '"'
+
+	return buf, nil
 }
 
 // UnmarshalJSON parses the JSON-encoded data and stores the result in id.