Add an explicit UndefinedValue type

The type is required to distinguish between a null
entry and a non existant entry in objects and arrays.

Now trying to read a non existant key or an out of
bounds value in the array will return an undefined
JsonValue.

Also added a private constructor to JsonValue to
avoid implicit conversions from const char * to bool
when constructing values.

Change-Id: Icbb065503af0eb828f8c1fc681b329be8b23cb46
Reviewed-by: Hicks James <jamey.hicks@nokia.com>

6 files changed, 65 insertions, 28 deletions

diff --git a/src/qjsonarray.cpp b/src/qjsonarray.cpp
index 6c54cb6..b9a0dd2 100644
--- a/src/qjsonarray.cpp
+++ b/src/qjsonarray.cpp
@@ -94,7 +94,7 @@ bool JsonArray::isEmpty() const
 JsonValue JsonArray::at(int i) const
 {
     if (!a || i < 0 || i >= (int)a->length)
-        return JsonValue();
+        return JsonValue(UndefinedValue);
 
     return JsonValue(d, a, a->at(i));
 }
@@ -127,7 +127,7 @@ void JsonArray::removeAt(int i)
 JsonValue JsonArray::takeAt(int i)
 {
     if (!a || i < 0 || i >= (int)a->length)
-        return JsonValue();
+        return JsonValue(UndefinedValue);
 
     detach();
 
@@ -153,7 +153,7 @@ void JsonArray::insert(int i, const JsonValue &value)
 
     int valueOffset = a->reserveSpace(valueSize, i, 1);
     Value &v = (*a)[i];
-    v.type = value.t;
+    v.type = (value.t == UndefinedValue ? NullValue : value.t);
     v.compressed = compressed;
     v.val = value.valueToStore(valueOffset);
     if (valueSize)
diff --git a/src/qjsonglobal.h b/src/qjsonglobal.h
index 09cc9fb..970a8f2 100644
--- a/src/qjsonglobal.h
+++ b/src/qjsonglobal.h
@@ -27,7 +27,8 @@ namespace QtJson
         NumberValue = 0x2,
         StringValue = 0x3,
         ArrayValue = 0x4,
-        ObjectValue = 0x5
+        ObjectValue = 0x5,
+        UndefinedValue = 0x80
     };
 
 }
diff --git a/src/qjsonobject.cpp b/src/qjsonobject.cpp
index 0b02dea..209a5d7 100644
--- a/src/qjsonobject.cpp
+++ b/src/qjsonobject.cpp
@@ -136,7 +136,7 @@ JsonValue JsonObject::value(const QString &key) const
                 return JsonValue(d, o, e->value);
         }
     }
-    return JsonValue();
+    return JsonValue(UndefinedValue);
 }
 
 static bool useCompressed(const QString &s)
@@ -155,6 +155,11 @@ static bool useCompressed(const QString &s)
 
 void JsonObject::insert(const QString &key, const JsonValue &value)
 {
+    if (value.t == UndefinedValue) {
+        remove(key);
+        return;
+    }
+
     bool compressed;
     int valueSize = value.requiredStorage(&compressed);
 
@@ -208,11 +213,11 @@ void JsonObject::remove(const QString &key)
 JsonValue JsonObject::take(const QString &key)
 {
     if (!o)
-        return JsonValue();
+        return JsonValue(UndefinedValue);
 
     int index = o->indexOf(key);
     if (index < 0)
-        return JsonValue();
+        return JsonValue(UndefinedValue);
 
     Entry *e = o->entryAt(index);
     o->removeItems(index, 1);
diff --git a/src/qjsonvalue.cpp b/src/qjsonvalue.cpp
index 2527500..15d248a 100644
--- a/src/qjsonvalue.cpp
+++ b/src/qjsonvalue.cpp
@@ -12,8 +12,8 @@ using namespace QtJson;
 
 static const Base emptyBase = { sizeof(Base), 0, 0, 0 };
 
-JsonValue::JsonValue()
-    : t(NullValue), d(0), dbl(0.)
+JsonValue::JsonValue(ValueType type)
+    : t(type), d(0), dbl(0.)
 {
 }
 
@@ -22,6 +22,7 @@ JsonValue::JsonValue(Data *data, Base *base, const Value &v)
 {
     t = (ValueType)v.type;
     switch (t) {
+    case UndefinedValue:
     case NullValue:
         dbl = 0;
         break;
@@ -191,6 +192,7 @@ QVariant JsonValue::toVariant() const
     case ObjectValue:
         return JsonObject(d, object).toVariantMap();
     case NullValue:
+    case UndefinedValue:
         break;
     }
     return QVariant();
@@ -288,6 +290,7 @@ bool JsonValue::operator==(const JsonValue &other) const
         return false;
 
     switch (t) {
+    case UndefinedValue:
     case NullValue:
         break;
     case BooleanValue:
@@ -347,6 +350,7 @@ int JsonValue::requiredStorage(bool *compressed) const
         return array ? array->size : sizeof(Array);
     case ObjectValue:
         return object ? object->size : sizeof(Object);
+    case UndefinedValue:
     case NullValue:
     case BooleanValue:
         break;
@@ -357,6 +361,7 @@ int JsonValue::requiredStorage(bool *compressed) const
 uint JsonValue::valueToStore(uint offset) const
 {
     switch (t) {
+    case UndefinedValue:
     case NullValue:
         break;
     case BooleanValue:
diff --git a/src/qjsonvalue.h b/src/qjsonvalue.h
index 74f2702..6ace201 100644
--- a/src/qjsonvalue.h
+++ b/src/qjsonvalue.h
@@ -9,7 +9,7 @@ namespace QtJson {
 
 class JsonValue {
 public:
-    JsonValue();
+    JsonValue(ValueType = NullValue);
     JsonValue(bool b);
     JsonValue(double n);
     JsonValue(int n);
@@ -27,8 +27,7 @@ public:
     QVariant toVariant() const;
 
     ValueType type() const;
-
-//    template <> value() const;
+    inline bool isUndefined() const { return type() == UndefinedValue; }
 
     void setValue(bool);
     void setValue(double);
@@ -51,6 +50,8 @@ public:
     void detach();
 
 private:
+    // avoid implicit conversions from char * to bool
+    inline JsonValue(const void *) {}
     friend class Data;
     friend class Value;
     friend class JsonArray;
diff --git a/tests/auto/tst_qtjson.cpp b/tests/auto/tst_qtjson.cpp
index da1cc57..8926a4c 100644
--- a/tests/auto/tst_qtjson.cpp
+++ b/tests/auto/tst_qtjson.cpp
@@ -73,6 +73,8 @@ private Q_SLOTS:
     void nullArrays();
     void nullObject();
 
+    void undefinedValues();
+
     void fromVariantMap();
     void toVariantMap();
 
@@ -163,7 +165,7 @@ void TestQtJson::testObjectSimple()
 
     // if we put a JsonValue into the JsonObject and retreive
     // it, it should be identical.
-    JsonValue value("foo");
+    JsonValue value(QLatin1String("foo"));
     object.insert("value", value);
     QCOMPARE(object.value("value"), value);
 
@@ -196,7 +198,7 @@ void TestQtJson::testArraySimple()
 
     // if we put a JsonValue into the JsonArray and retreive
     // it, it should be identical.
-    JsonValue value("foo");
+    JsonValue value(QLatin1String("foo"));
     array.append(value);
     QCOMPARE(array.at(3), value);
 
@@ -217,15 +219,15 @@ void TestQtJson::testArraySimple()
     QCOMPARE(array.last().type(), NullValue);
     QCOMPARE(array.last(), JsonValue());
 
-    QCOMPARE(array.at(-1), JsonValue());
-    QCOMPARE(array.at(array.size()), JsonValue());
+    QCOMPARE(array.at(-1), JsonValue(UndefinedValue));
+    QCOMPARE(array.at(array.size()), JsonValue(UndefinedValue));
 }
 
 void TestQtJson::testValueObject()
 {
     JsonObject object;
     object.insert("number", 999.);
-    object.insert("string", "test");
+    object.insert("string", QLatin1String("test"));
     object.insert("boolean", true);
 
     JsonValue value(object);
@@ -243,7 +245,7 @@ void TestQtJson::testValueArray()
 {
     JsonArray array;
     array.append(999.);
-    array.append("test");
+    array.append(QLatin1String("test"));
     array.append(true);
 
     JsonValue value(array);
@@ -253,7 +255,7 @@ void TestQtJson::testValueArray()
     QCOMPARE(value.toArray(), array);
 
     // if we modify the original array, it should detach
-    array.append("test");
+    array.append(QLatin1String("test"));
     QVERIFY2(value.toArray() != array, "array should have detached");
 }
 
@@ -379,7 +381,7 @@ void TestQtJson::testDocument()
     QCOMPARE(doc.isEmpty(), false);
     QCOMPARE(doc.type(), ObjectValue);
 
-    object.insert(QLatin1String("Key"), "Value");
+    object.insert(QLatin1String("Key"), QLatin1String("Value"));
     doc.setObject(object);
     QCOMPARE(doc.isEmpty(), false);
     QCOMPARE(doc.type(), ObjectValue);
@@ -429,9 +431,9 @@ void TestQtJson::nullArrays()
     QVERIFY(nonNull != nullArray);
 
     QCOMPARE(nullArray.size(), 0);
-    QCOMPARE(nullArray.takeAt(0), JsonValue());
-    QCOMPARE(nullArray.first(), JsonValue());
-    QCOMPARE(nullArray.last(), JsonValue());
+    QCOMPARE(nullArray.takeAt(0), JsonValue(UndefinedValue));
+    QCOMPARE(nullArray.first(), JsonValue(UndefinedValue));
+    QCOMPARE(nullArray.last(), JsonValue(UndefinedValue));
     nullArray.removeAt(0);
     nullArray.removeAt(-1);
 
@@ -439,9 +441,9 @@ void TestQtJson::nullArrays()
     nullArray.removeAt(0);
 
     QCOMPARE(nullArray.size(), 0);
-    QCOMPARE(nullArray.takeAt(0), JsonValue());
-    QCOMPARE(nullArray.first(), JsonValue());
-    QCOMPARE(nullArray.last(), JsonValue());
+    QCOMPARE(nullArray.takeAt(0), JsonValue(UndefinedValue));
+    QCOMPARE(nullArray.first(), JsonValue(UndefinedValue));
+    QCOMPARE(nullArray.last(), JsonValue(UndefinedValue));
     nullArray.removeAt(0);
     nullArray.removeAt(-1);
 
@@ -463,7 +465,7 @@ void TestQtJson::nullObject()
     QCOMPARE(nullObject.keys(), QStringList());
     nullObject.remove("foo");
     QCOMPARE(nullObject, JsonObject());
-    QCOMPARE(nullObject.take("foo"), JsonValue());
+    QCOMPARE(nullObject.take("foo"), JsonValue(UndefinedValue));
     QCOMPARE(nullObject.contains("foo"), false);
 
     nullObject.detach(16);
@@ -476,10 +478,33 @@ void TestQtJson::nullObject()
     QCOMPARE(nullObject.keys(), QStringList());
     nullObject.remove("foo");
     QCOMPARE(nullObject, JsonObject());
-    QCOMPARE(nullObject.take("foo"), JsonValue());
+    QCOMPARE(nullObject.take("foo"), JsonValue(UndefinedValue));
     QCOMPARE(nullObject.contains("foo"), false);
 }
 
+void TestQtJson::undefinedValues()
+{
+    JsonObject object;
+    object.insert("Key", JsonValue(UndefinedValue));
+    QCOMPARE(object.numKeys(), 0);
+
+    object.insert("Key", QLatin1String("Value"));
+    QCOMPARE(object.numKeys(), 1);
+    QCOMPARE(object.value("Key").type(), StringValue);
+    QCOMPARE(object.value("foo").type(), UndefinedValue);
+    object.insert("Key", JsonValue(UndefinedValue));
+    QCOMPARE(object.numKeys(), 0);
+    QCOMPARE(object.value("Key").type(), UndefinedValue);
+
+    JsonArray array;
+    array.append(JsonValue(UndefinedValue));
+    QCOMPARE(array.size(), 1);
+    QCOMPARE(array.at(0).type(), NullValue);
+
+    QCOMPARE(array.at(1).type(), UndefinedValue);
+    QCOMPARE(array.at(-1).type(), UndefinedValue);
+}
+
 
 void TestQtJson::fromVariantMap()
 {