From 20b9f5d6f15639897c741298cc8087363a4c7221 Mon Sep 17 00:00:00 2001
From: mpl <mathieu.lonjaret@gmail.com>
Date: Thu, 23 Jan 2014 16:40:28 +0100
Subject: [PATCH] pkg/types: add InvertedBool

Will be needed for json tagged serverconfig in subsequent commit.

http://camlistore.org/issue/339

Change-Id: I41ae6e9918b23eb9bdb471e402de0415f3499dc3
---
 pkg/types/types.go      | 21 ++++++++++++++++++
 pkg/types/types_test.go | 49 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/pkg/types/types.go b/pkg/types/types.go
index f76ed1f8f..b4431c7bf 100644
--- a/pkg/types/types.go
+++ b/pkg/types/types.go
@@ -173,3 +173,24 @@ func (v *varStatReadSeeker) Read(p []byte) (int, error) {
 func (v *varStatReadSeeker) Seek(offset int64, whence int) (int64, error) {
 	return v.rs.Seek(offset, whence)
 }
+
+// InvertedBool is a bool that marshals to and from JSON with the opposite of its in-memory value.
+type InvertedBool bool
+
+func (ib InvertedBool) MarshalJSON() ([]byte, error) {
+	return json.Marshal(!bool(ib))
+}
+
+func (ib *InvertedBool) UnmarshalJSON(b []byte) error {
+	var bo bool
+	if err := json.Unmarshal(b, &bo); err != nil {
+		return err
+	}
+	*ib = InvertedBool(!bo)
+	return nil
+}
+
+// Get returns the logical value of ib.
+func (ib InvertedBool) Get() bool {
+	return !bool(ib)
+}
diff --git a/pkg/types/types_test.go b/pkg/types/types_test.go
index e3f847c06..8708c7dd4 100644
--- a/pkg/types/types_test.go
+++ b/pkg/types/types_test.go
@@ -101,3 +101,52 @@ func TestTime3339_empty(t *testing.T) {
 		}
 	}
 }
+
+func TestInvertedBool_Unmarshal(t *testing.T) {
+	tests := []struct {
+		json string
+		want bool
+	}{
+		{json: `{}`, want: true},
+		{json: `{"key": true}`, want: true},
+		{json: `{"key": false}`, want: false},
+	}
+	type O struct {
+		Key InvertedBool
+	}
+	for _, tt := range tests {
+		obj := &O{}
+		if err := json.Unmarshal([]byte(tt.json), obj); err != nil {
+			t.Fatalf("Could not unmarshal %s: %v", tt.json, err)
+		}
+		if obj.Key.Get() != tt.want {
+			t.Errorf("Unmarshaled %s as InvertedBool; got %v, wanted %v", tt.json, obj.Key.Get(), tt.want)
+		}
+	}
+}
+
+func TestInvertedBool_Marshal(t *testing.T) {
+	tests := []struct {
+		internalVal bool
+		want        string
+	}{
+		{internalVal: true, want: `{"key":false}`},
+		{internalVal: false, want: `{"key":true}`},
+	}
+	type O struct {
+		Key InvertedBool `json:"key"`
+	}
+	for _, tt := range tests {
+
+		obj := &O{
+			Key: InvertedBool(tt.internalVal),
+		}
+		b, err := json.Marshal(obj)
+		if err != nil {
+			t.Fatalf("Could not marshal %v: %v", tt.internalVal, err)
+		}
+		if string(b) != tt.want {
+			t.Errorf("Marshaled InvertedBool %v; got %v, wanted %v", tt.internalVal, string(b), tt.want)
+		}
+	}
+}