v01.config accepts and applies json patch

go.mod

@@ -9,6 +9,7 @@ require (
 )
 
 require (
+	github.com/evanphx/json-patch/v5 v5.6.0 // indirect
 	github.com/hajimehoshi/oto v0.7.1 // indirect
 	github.com/micmonay/keybd_event v1.1.1 // indirect
 	github.com/pkg/errors v0.9.1 // indirect

go.sum

@@ -1,5 +1,7 @@
 github.com/DATA-DOG/go-sqlmock v1.3.3/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
 github.com/d4l3k/messagediff v1.2.2-0.20190829033028-7e0a312ae40b/go.mod h1:Oozbb1TVXFac9FtSIxHBMnBCq2qeH/2KkEQxENCrlLo=
+github.com/evanphx/json-patch/v5 v5.6.0 h1:b91NhWfaz02IuVxO9faSllyAtNXHMPkC5J8sJCLunww=
+github.com/evanphx/json-patch/v5 v5.6.0/go.mod h1:G79N1coSVB93tBe7j6PhzjmR3/2VvlbKOFpnXhI9Bw4=
 github.com/faiface/beep v1.1.0 h1:A2gWP6xf5Rh7RG/p9/VAW2jRSDEGQm5sbOb38sf5d4c=
 github.com/faiface/beep v1.1.0/go.mod h1:6I8p6kK2q4opL/eWb+kAkk38ehnTunWeToJB+s51sT4=
 github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
@@ -15,6 +17,7 @@ github.com/hajimehoshi/oto v0.7.1 h1:I7maFPz5MBCwiutOrz++DLdbr4rTzBsbBuV2VpgU9kk
 github.com/hajimehoshi/oto v0.7.1/go.mod h1:wovJ8WWMfFKvP587mhHgot/MBr4DnNy9m6EepeVGnos=
 github.com/icza/bitio v1.0.0/go.mod h1:0jGnlLAx8MKMr9VGnn/4YrvZiprkvBelsVIbA9Jjr9A=
 github.com/icza/mighty v0.0.0-20180919140131-cfd07d671de6/go.mod h1:xQig96I1VNBDIWGCdTt54nHt6EeI639SmHycLYL7FkA=
+github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/jfreymuth/oggvorbis v1.0.1/go.mod h1:NqS+K+UXKje0FUYUPosyQ+XTVvjmVjps1aEZH1sumIk=
 github.com/jfreymuth/vorbis v1.0.0/go.mod h1:8zy3lUAm9K/rJJk223RKy6vjCZTWC61NA2QD06bfOE0=
 github.com/lucasb-eyer/go-colorful v1.0.2/go.mod h1:0MS4r+7BZKSJ5mw4/S5MPN+qHFF1fYclkSPilDOKW0s=

src/device/input/parse/v01/config.go

@@ -1,5 +1,11 @@
 package v01
 
+import (
+	"encoding/json"
+
+	patch "github.com/evanphx/json-patch/v5"
+)
+
 type config struct {
 	Feedback struct {
 		Addr   string
@@ -14,3 +20,24 @@ type config struct {
 	}
 	Quiet bool
 }
+
+func (cfg config) WithJSONPatch(v interface{}) config {
+	originalData, _ := json.Marshal(cfg)
+	patchData, err := json.Marshal(v)
+	if err != nil {
+		return cfg
+	}
+	patcher, err := patch.DecodePatch(patchData)
+	if err != nil {
+		return cfg
+	}
+	patchedData, err := patcher.Apply(originalData)
+	if err != nil {
+		return cfg
+	}
+	var patched config
+	if err := json.Unmarshal(patchedData, &patched); err != nil {
+		return cfg
+	}
+	return patched
+}

src/device/input/parse/v01/config_test.go

@@ -0,0 +1,79 @@
+package v01
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestConfigPatch(t *testing.T) {
+	cases := map[string]struct {
+		cfg   config
+		patch interface{}
+		want  config
+	}{
+		"nil patch": {
+			cfg:   config{Quiet: true},
+			patch: nil,
+			want:  config{Quiet: true},
+		},
+		"[] patch": {
+			cfg:   config{Quiet: true},
+			patch: []interface{}{},
+			want:  config{Quiet: true},
+		},
+		"set fake field": {
+			cfg: config{Quiet: true},
+			patch: []interface{}{
+				map[string]interface{}{"op": "add", "path": "/Fake", "value": true},
+			},
+			want: config{Quiet: true},
+		},
+		"remove field": {
+			cfg: config{Quiet: true},
+			patch: []interface{}{
+				map[string]interface{}{"op": "remove", "path": "/Quiet"},
+			},
+			want: config{Quiet: false},
+		},
+		"replace field with valid": {
+			cfg: config{Quiet: true},
+			patch: []interface{}{
+				map[string]interface{}{"op": "replace", "path": "/Quiet", "value": false},
+			},
+			want: config{Quiet: false},
+		},
+		"replace field with invalid": {
+			cfg: config{Quiet: true},
+			patch: []interface{}{
+				map[string]interface{}{"op": "replace", "path": "/Quiet", "value": "teehee"},
+			},
+			want: config{Quiet: true},
+		},
+		"test and noop": {
+			cfg: config{Quiet: true},
+			patch: []interface{}{
+				map[string]interface{}{"op": "test", "path": "/Quiet", "value": false},
+				map[string]interface{}{"op": "replace", "path": "/Quiet", "value": false},
+			},
+			want: config{Quiet: true},
+		},
+		"test and apply": {
+			cfg: config{Quiet: true},
+			patch: []interface{}{
+				map[string]interface{}{"op": "test", "path": "/Quiet", "value": true},
+				map[string]interface{}{"op": "replace", "path": "/Quiet", "value": false},
+			},
+			want: config{Quiet: false},
+		},
+	}
+
+	for name, d := range cases {
+		c := d
+		t.Run(name, func(t *testing.T) {
+			got := c.cfg.WithJSONPatch(c.patch)
+			if fmt.Sprintf("%+v", got) != fmt.Sprintf("%+v", c.want) {
+				t.Errorf("(%+v).Patch(%+v) want %+v, got %+v", c.cfg, c.patch, c.want, got)
+			}
+		})
+	}
+}