Implement support for frozen arrays and dictionaries

doc/18-library-reference.md

@@ -1260,6 +1260,14 @@ Signature:
 
 Returns true if the array contains the specified value, false otherwise.
 
+### Array#freeze <a id="array-freeze"></a>
+
+Signature:
+
+    function freeze()
+
+Disallows further modifications to this array. Trying to modify the array will result in an exception.
+
 ### Array#len <a id="array-len"></a>
 
 Signature:
@@ -1395,6 +1403,14 @@ Signature:
 
 Returns true if a dictionary item with the specified `key` exists, false otherwise.
 
+### Dictionary#freeze <a id="dictionary-freeze"></a>
+
+Signature:
+
+    function freeze()
+
+Disallows further modifications to this dictionary. Trying to modify the dictionary will result in an exception.
+
 ### Dictionary#len <a id="dictionary-len"></a>
 
 Signature:

lib/base/array-script.cpp

@@ -245,6 +245,13 @@ static Array::Ptr ArrayUnique()
 	return Array::FromSet(result);
 }
 
+static void ArrayFreeze()
+{
+	ScriptFrame *vframe = ScriptFrame::GetCurrentFrame();
+	Array::Ptr self = static_cast<Array::Ptr>(vframe->Self);
+	self->Freeze();
+}
+
 Object::Ptr Array::GetPrototype()
 {
 	static Dictionary::Ptr prototype = new Dictionary({
@@ -264,7 +271,8 @@ Object::Ptr Array::GetPrototype()
 		{ "filter", new Function("Array#filter", ArrayFilter, { "func" }, true) },
 		{ "any", new Function("Array#any", ArrayAny, { "func" }, true) },
 		{ "all", new Function("Array#all", ArrayAll, { "func" }, true) },
-		{ "unique", new Function("Array#unique", ArrayUnique, {}, true) }
+		{ "unique", new Function("Array#unique", ArrayUnique, {}, true) },
+		{ "freeze", new Function("Array#freeze", ArrayFreeze, {}) }
 	});
 
 	return prototype;

lib/base/array.cpp

@@ -67,6 +67,9 @@ void Array::Set(SizeType index, const Value& value)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.at(index) = value;
 }
 
@@ -80,6 +83,9 @@ void Array::Set(SizeType index, Value&& value)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.at(index).Swap(value);
 }
 
@@ -92,6 +98,9 @@ void Array::Add(Value value)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.push_back(std::move(value));
 }
 
@@ -160,6 +169,9 @@ void Array::Insert(SizeType index, Value value)
 
 	ASSERT(index <= m_Data.size());
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.insert(m_Data.begin() + index, std::move(value));
 }
 
@@ -172,6 +184,9 @@ void Array::Remove(SizeType index)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.erase(m_Data.begin() + index);
 }
 
@@ -184,6 +199,9 @@ void Array::Remove(Array::Iterator it)
 {
 	ASSERT(OwnsLock());
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.erase(it);
 }
 
@@ -191,6 +209,9 @@ void Array::Resize(SizeType newSize)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.resize(newSize);
 }
 
@@ -198,6 +219,9 @@ void Array::Clear()
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.clear();
 }
 
@@ -205,6 +229,9 @@ void Array::Reserve(SizeType newSize)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	m_Data.reserve(newSize);
 }
 
@@ -213,6 +240,9 @@ void Array::CopyTo(const Array::Ptr& dest) const
 	ObjectLock olock(this);
 	ObjectLock xlock(dest);
 
+	if (dest->m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	std::copy(m_Data.begin(), m_Data.end(), std::back_inserter(dest->m_Data));
 }
 
@@ -261,6 +291,10 @@ Array::Ptr Array::Reverse() const
 void Array::Sort()
 {
 	ObjectLock olock(this);
+
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Array must not be modified."));
+
 	std::sort(m_Data.begin(), m_Data.end());
 }
 
@@ -271,6 +305,12 @@ String Array::ToString() const
 	return msgbuf.str();
 }
 
+void Array::Freeze()
+{
+	ObjectLock olock(this);
+	m_Frozen = true;
+}
+
 Value Array::GetFieldByName(const String& field, bool sandboxed, const DebugInfo& debugInfo) const
 {
 	int index;

lib/base/array.hpp

@@ -112,11 +112,14 @@ public:
 
 	String ToString() const override;
 
+	void Freeze();
+
 	Value GetFieldByName(const String& field, bool sandboxed, const DebugInfo& debugInfo) const override;
 	void SetFieldByName(const String& field, const Value& value, const DebugInfo& debugInfo) override;
 
 private:
 	std::vector<Value> m_Data; /**< The data for the array. */
+	bool m_Frozen{false};
 };
 
 Array::Iterator begin(const Array::Ptr& x);

lib/base/dictionary-script.cpp

@@ -91,6 +91,13 @@ static Array::Ptr DictionaryValues()
 	return new Array(std::move(values));
 }
 
+static void DictionaryFreeze()
+{
+	ScriptFrame *vframe = ScriptFrame::GetCurrentFrame();
+	Dictionary::Ptr self = static_cast<Dictionary::Ptr>(vframe->Self);
+	self->Freeze();
+}
+
 Object::Ptr Dictionary::GetPrototype()
 {
 	static Dictionary::Ptr prototype = new Dictionary({
@@ -101,7 +108,8 @@ Object::Ptr Dictionary::GetPrototype()
 		{ "contains", new Function("Dictionary#contains", DictionaryContains, { "key" }, true) },
 		{ "shallow_clone", new Function("Dictionary#shallow_clone", DictionaryShallowClone, {}, true) },
 		{ "keys", new Function("Dictionary#keys", DictionaryKeys, {}, true) },
-		{ "values", new Function("Dictionary#values", DictionaryValues, {}, true) }
+		{ "values", new Function("Dictionary#values", DictionaryValues, {}, true) },
+		{ "freeze", new Function("Dictionary#freeze", DictionaryFreeze, {}) }
 	});
 
 	return prototype;

lib/base/dictionary.cpp

@@ -94,6 +94,9 @@ void Dictionary::Set(const String& key, Value value)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Dictionary must not be modified."));
+
 	m_Data[key] = std::move(value);
 }
 
@@ -159,6 +162,9 @@ void Dictionary::Remove(Dictionary::Iterator it)
 {
 	ASSERT(OwnsLock());
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Dictionary must not be modified."));
+
 	m_Data.erase(it);
 }
 
@@ -171,6 +177,9 @@ void Dictionary::Remove(const String& key)
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Dictionary must not be modified."));
+
 	Dictionary::Iterator it;
 	it = m_Data.find(key);
 
@@ -187,6 +196,9 @@ void Dictionary::Clear()
 {
 	ObjectLock olock(this);
 
+	if (m_Frozen)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Dictionary must not be modified."));
+
 	m_Data.clear();
 }
 
@@ -260,6 +272,12 @@ String Dictionary::ToString() const
 	return msgbuf.str();
 }
 
+void Dictionary::Freeze()
+{
+	ObjectLock olock(this);
+	m_Frozen = true;
+}
+
 Value Dictionary::GetFieldByName(const String& field, bool, const DebugInfo& debugInfo) const
 {
 	Value value;

lib/base/dictionary.hpp

@@ -83,6 +83,8 @@ public:
 
 	String ToString() const override;
 
+	void Freeze();
+
 	Value GetFieldByName(const String& field, bool sandboxed, const DebugInfo& debugInfo) const override;
 	void SetFieldByName(const String& field, const Value& value, const DebugInfo& debugInfo) override;
 	bool HasOwnField(const String& field) const override;
@@ -90,6 +92,7 @@ public:
 
 private:
 	std::map<String, Value> m_Data; /**< The data for the dictionary. */
+	bool m_Frozen{false};
 };
 
 Dictionary::Iterator begin(const Dictionary::Ptr& x);