Pull request: all: imp updater

Merge in DNS/adguard-home from imp-updater to master

Squashed commit of the following:

commit 6ed487359e56a35b36f13dcbf2efbf2a7a2d8734
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Jun 9 16:29:35 2022 +0300

    all: imp logs, err handling

commit e930044cb619a43e5a44c230dadbe2228e9a93f5
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Jun 9 15:53:35 2022 +0300

    all: imp updater

internal/aghalg/nullbool.go

@@ -0,0 +1,59 @@
+package aghalg
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+)
+
+// NullBool is a nullable boolean.  Use these in JSON requests and responses
+// instead of pointers to bool.
+type NullBool uint8
+
+// NullBool values
+const (
+	NBNull NullBool = iota
+	NBTrue
+	NBFalse
+)
+
+// String implements the fmt.Stringer interface for NullBool.
+func (nb NullBool) String() (s string) {
+	switch nb {
+	case NBNull:
+		return "null"
+	case NBTrue:
+		return "true"
+	case NBFalse:
+		return "false"
+	}
+
+	return fmt.Sprintf("!invalid NullBool %d", uint8(nb))
+}
+
+// BoolToNullBool converts a bool into a NullBool.
+func BoolToNullBool(cond bool) (nb NullBool) {
+	if cond {
+		return NBTrue
+	}
+
+	return NBFalse
+}
+
+// type check
+var _ json.Unmarshaler = (*NullBool)(nil)
+
+// UnmarshalJSON implements the json.Unmarshaler interface for *NullBool.
+func (nb *NullBool) UnmarshalJSON(b []byte) (err error) {
+	if len(b) == 0 || bytes.Equal(b, []byte("null")) {
+		*nb = NBNull
+	} else if bytes.Equal(b, []byte("true")) {
+		*nb = NBTrue
+	} else if bytes.Equal(b, []byte("false")) {
+		*nb = NBFalse
+	} else {
+		return fmt.Errorf("unmarshalling json data into aghalg.NullBool: bad value %q", b)
+	}
+
+	return nil
+}

internal/aghalg/nullbool_test.go

@@ -0,0 +1,67 @@
+package aghalg_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/aghalg"
+	"github.com/AdguardTeam/golibs/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNullBool_UnmarshalJSON(t *testing.T) {
+	testCases := []struct {
+		name       string
+		wantErrMsg string
+		data       []byte
+		want       aghalg.NullBool
+	}{{
+		name:       "empty",
+		wantErrMsg: "",
+		data:       []byte{},
+		want:       aghalg.NBNull,
+	}, {
+		name:       "null",
+		wantErrMsg: "",
+		data:       []byte("null"),
+		want:       aghalg.NBNull,
+	}, {
+		name:       "true",
+		wantErrMsg: "",
+		data:       []byte("true"),
+		want:       aghalg.NBTrue,
+	}, {
+		name:       "false",
+		wantErrMsg: "",
+		data:       []byte("false"),
+		want:       aghalg.NBFalse,
+	}, {
+		name:       "invalid",
+		wantErrMsg: `unmarshalling json data into aghalg.NullBool: bad value "invalid"`,
+		data:       []byte("invalid"),
+		want:       aghalg.NBNull,
+	}}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			var got aghalg.NullBool
+			err := got.UnmarshalJSON(tc.data)
+			testutil.AssertErrorMsg(t, tc.wantErrMsg, err)
+
+			assert.Equal(t, tc.want, got)
+		})
+	}
+
+	t.Run("json", func(t *testing.T) {
+		want := aghalg.NBTrue
+		var got struct {
+			A aghalg.NullBool
+		}
+
+		err := json.Unmarshal([]byte(`{"A":true}`), &got)
+		require.NoError(t, err)
+
+		assert.Equal(t, want, got.A)
+	})
+}