/// <summary>
/// Deletes a property from the schema.
/// </summary>
/// <param name="key"> The property key of the property to delete. </param>
/// <returns> A new schema without the property. </returns>
public HiddenClassSchema DeleteProperty(object key)
{
// Check if there is a transition to the schema already.
HiddenClassSchema newSchema = null;
if (this.deleteTransitions != null)
{
this.deleteTransitions.TryGetValue(key, out newSchema);
}
if (newSchema == null)
{
// Create a new schema based on this one.
var properties = this.properties == null?CreatePropertiesDictionary() : new Dictionary <object, SchemaProperty>(this.properties);
if (properties.Remove(key) == false)
{
throw new InvalidOperationException(string.Format("The property '{0}' does not exist.", key));
}
newSchema = new HiddenClassSchema(properties, this.NextValueIndex);
// Add a transition to the new schema.
if (this.deleteTransitions == null)
{
this.deleteTransitions = new Dictionary <object, HiddenClassSchema>(1);
}
this.deleteTransitions.Add(key, newSchema);
}
return(newSchema);
}
/// <summary>
/// Called by derived classes to create a new object instance.
/// </summary>
/// <param name="prototype"> The next object in the prototype chain. Cannot be <c>null</c>. </param>
protected ObjectInstance(ObjectInstance prototype)
{
if (prototype == null)
throw new ArgumentNullException("prototype");
this.prototype = prototype;
this.engine = prototype.Engine;
this.schema = this.engine.EmptySchema;
}
/// <summary>
/// Called by derived classes to create a new object instance.
/// </summary>
/// <param name="engine"> The script engine associated with this object. </param>
/// <param name="prototype"> The next object in the prototype chain. Can be <c>null</c>. </param>
protected ObjectInstance(ScriptEngine engine, ObjectInstance prototype)
{
if (engine == null)
throw new ArgumentNullException("engine");
this.engine = engine;
this.prototype = prototype;
this.schema = engine.EmptySchema;
}
/// <summary>
/// Enumerates the property names for this schema.
/// </summary>
/// <returns> An enumerable collection of property names. </returns>
public IEnumerable <object> EnumeratePropertyNames()
{
if (this.properties == null)
{
this.properties = CreatePropertiesDictionary();
}
this.parent = null; // Prevents the properties dictionary from being stolen while an enumeration is in progress.
foreach (var pair in this.properties)
{
yield return(pair.Key);
}
}
/// <summary>
/// Enumerates the property names and values for this schema.
/// </summary>
/// <param name="values"> The array containing the property values. </param>
/// <returns> An enumerable collection of property names and values. </returns>
public IEnumerable <PropertyNameAndValue> EnumeratePropertyNamesAndValues(object[] values)
{
if (this.properties == null)
{
this.properties = CreatePropertiesDictionary();
}
this.parent = null; // Prevents the properties dictionary from being stolen while an enumeration is in progress.
foreach (var pair in this.properties)
{
yield return(new PropertyNameAndValue(pair.Key, values[pair.Value.Index], pair.Value.Attributes));
}
}
/// <summary>
/// Modifies the attributes for a property in the schema.
/// </summary>
/// <param name="key"> The property key of the property to modify. </param>
/// <param name="attributes"> The new attributes. </param>
/// <returns> A new schema with the modified property. </returns>
public HiddenClassSchema SetPropertyAttributes(object key, PropertyAttributes attributes)
{
// Package the name and attributes into a struct.
var transitionInfo = new TransitionInfo()
{
Key = key, Attributes = attributes
};
// Check if there is a transition to the schema already.
HiddenClassSchema newSchema = null;
if (this.modifyTransitions != null)
{
this.modifyTransitions.TryGetValue(transitionInfo, out newSchema);
}
if (newSchema == null)
{
// Create the properties dictionary if it hasn't already been created.
if (this.properties == null)
{
this.properties = CreatePropertiesDictionary();
}
// Check the attributes differ from the existing attributes.
SchemaProperty propertyInfo;
if (this.properties.TryGetValue(key, out propertyInfo) == false)
{
throw new InvalidOperationException(string.Format("The property '{0}' does not exist.", key));
}
if (attributes == propertyInfo.Attributes)
{
return(this);
}
// Create a new schema based on this one.
var properties = new Dictionary <object, SchemaProperty>(this.properties);
properties[key] = new SchemaProperty(propertyInfo.Index, attributes);
newSchema = new HiddenClassSchema(properties, this.NextValueIndex);
// Add a transition to the new schema.
if (this.modifyTransitions == null)
{
this.modifyTransitions = new Dictionary <TransitionInfo, HiddenClassSchema>(1);
}
this.modifyTransitions.Add(transitionInfo, newSchema);
}
return(newSchema);
}
/// <summary>
/// Adds a property to the schema.
/// </summary>
/// <param name="key"> The property key of the property to add. </param>
/// <param name="attributes"> The property attributes. </param>
/// <returns> A new schema with the extra property. </returns>
public HiddenClassSchema AddProperty(object key, PropertyAttributes attributes = PropertyAttributes.FullAccess)
{
// Package the name and attributes into a struct.
var transitionInfo = new TransitionInfo()
{
Key = key, Attributes = attributes
};
// Check if there is a transition to the schema already.
HiddenClassSchema newSchema = null;
if (this.addTransitions != null)
{
this.addTransitions.TryGetValue(transitionInfo, out newSchema);
}
if (newSchema == null)
{
if (this.parent == null)
{
// Create a new schema based on this one. A complete copy must be made of the properties hashtable.
var properties = new Dictionary <object, SchemaProperty>(this.properties);
properties.Add(key, new SchemaProperty(this.NextValueIndex, attributes));
newSchema = new HiddenClassSchema(properties, this.NextValueIndex + 1, this, transitionInfo);
}
else
{
// Create a new schema based on this one. The properties hashtable is "given
// away" so a copy does not have to be made.
if (this.properties == null)
{
this.properties = CreatePropertiesDictionary();
}
this.properties.Add(key, new SchemaProperty(this.NextValueIndex, attributes));
newSchema = new HiddenClassSchema(this.properties, this.NextValueIndex + 1, this, transitionInfo);
this.properties = null;
}
// Add a transition to the new schema.
if (this.addTransitions == null)
{
this.addTransitions = new Dictionary <TransitionInfo, HiddenClassSchema>(1);
}
this.addTransitions.Add(transitionInfo, newSchema);
}
return(newSchema);
}
/// <summary>
/// Adds multiple properties to the schema.
/// </summary>
/// <param name="properties"> The properties to add. </param>
/// <returns> A new schema with the extra properties. </returns>
public HiddenClassSchema AddProperties(IEnumerable <PropertyNameAndValue> properties)
{
if (this.properties == null)
{
var propertyDictionary = new Dictionary <object, SchemaProperty>(properties.Count());
int nextValueIndex = 0;
foreach (var property in properties)
{
propertyDictionary.Add(property.Key, new SchemaProperty(nextValueIndex++, property.Attributes));
}
return(new HiddenClassSchema(propertyDictionary, nextValueIndex));
}
else
{
// There are already properties in the schema. Just add them one by one.
HiddenClassSchema newSchema = this;
foreach (var property in properties)
{
newSchema = AddProperty(property.Key, property.Attributes);
}
return(newSchema);
}
}
/// <summary>
/// Creates a new HiddenClassSchema instance from an add operation.
/// </summary>
private HiddenClassSchema(Dictionary<string, SchemaProperty> properties, int nextValueIndex, HiddenClassSchema parent, TransitionInfo addPropertyTransitionInfo)
: this(properties, nextValueIndex)
{
this.parent = parent;
this.addPropertyTransitionInfo = addPropertyTransitionInfo;
}
/// <summary>
/// Modifies the attributes for a property in the schema.
/// </summary>
/// <param name="name"> The name of the property to modify. </param>
/// <param name="attributes"> The new attributes. </param>
/// <returns> A new schema with the modified property. </returns>
public HiddenClassSchema SetPropertyAttributes(string name, PropertyAttributes attributes)
{
// Package the name and attributes into a struct.
var transitionInfo = new TransitionInfo() { Name = name, Attributes = attributes };
// Check if there is a transition to the schema already.
HiddenClassSchema newSchema = null;
if (this.modifyTransitions != null)
this.modifyTransitions.TryGetValue(transitionInfo, out newSchema);
if (newSchema == null)
{
// Create the properties dictionary if it hasn't already been created.
if (this.properties == null)
this.properties = CreatePropertiesDictionary();
// Check the attributes differ from the existing attributes.
SchemaProperty propertyInfo;
if (this.properties.TryGetValue(name, out propertyInfo) == false)
throw new InvalidOperationException(string.Format("The property '{0}' does not exist.", name));
if (attributes == propertyInfo.Attributes)
return this;
// Create a new schema based on this one.
var properties = new Dictionary<string, SchemaProperty>(this.properties);
properties[name] = new SchemaProperty(propertyInfo.Index, attributes);
newSchema = new HiddenClassSchema(properties, this.NextValueIndex);
// Add a transition to the new schema.
if (this.modifyTransitions == null)
this.modifyTransitions = new Dictionary<TransitionInfo, HiddenClassSchema>(1);
this.modifyTransitions.Add(transitionInfo, newSchema);
}
return newSchema;
}
/// <summary>
/// Deletes a property from the schema.
/// </summary>
/// <param name="name"> The name of the property to delete. </param>
/// <returns> A new schema without the property. </returns>
public HiddenClassSchema DeleteProperty(string name)
{
// Check if there is a transition to the schema already.
HiddenClassSchema newSchema = null;
if (this.deleteTransitions != null)
this.deleteTransitions.TryGetValue(name, out newSchema);
if (newSchema == null)
{
// Create a new schema based on this one.
var properties = this.properties == null ? CreatePropertiesDictionary() : new Dictionary<string, SchemaProperty>(this.properties);
if (properties.Remove(name) == false)
throw new InvalidOperationException(string.Format("The property '{0}' does not exist.", name));
newSchema = new HiddenClassSchema(properties, this.NextValueIndex);
// Add a transition to the new schema.
if (this.deleteTransitions == null)
this.deleteTransitions = new Dictionary<string, HiddenClassSchema>(1);
this.deleteTransitions.Add(name, newSchema);
}
return newSchema;
}
/// <summary>
/// Adds a property to the schema.
/// </summary>
/// <param name="name"> The name of the property to add. </param>
/// <param name="attributes"> The property attributes. </param>
/// <returns> A new schema with the extra property. </returns>
public HiddenClassSchema AddProperty(string name, PropertyAttributes attributes = PropertyAttributes.FullAccess)
{
// Package the name and attributes into a struct.
var transitionInfo = new TransitionInfo() { Name = name, Attributes = attributes };
// Check if there is a transition to the schema already.
HiddenClassSchema newSchema = null;
if (this.addTransitions != null)
this.addTransitions.TryGetValue(transitionInfo, out newSchema);
if (newSchema == null)
{
if (this.parent == null)
{
// Create a new schema based on this one. A complete copy must be made of the properties hashtable.
var properties = new Dictionary<string, SchemaProperty>(this.properties);
properties.Add(name, new SchemaProperty(this.NextValueIndex, attributes));
newSchema = new HiddenClassSchema(properties, this.NextValueIndex + 1, this, transitionInfo);
}
else
{
// Create a new schema based on this one. The properties hashtable is "given
// away" so a copy does not have to be made.
if (this.properties == null)
this.properties = CreatePropertiesDictionary();
this.properties.Add(name, new SchemaProperty(this.NextValueIndex, attributes));
newSchema = new HiddenClassSchema(this.properties, this.NextValueIndex + 1, this, transitionInfo);
this.properties = null;
}
// Add a transition to the new schema.
if (this.addTransitions == null)
this.addTransitions = new Dictionary<TransitionInfo, HiddenClassSchema>(1);
this.addTransitions.Add(transitionInfo, newSchema);
}
return newSchema;
}
/// <summary>
/// Sets a property value and attributes, or adds a new property if it doesn't already
/// exist. Any existing attributes are ignored (and not modified).
/// </summary>
/// <param name="propertyName"> The name of the property. </param>
/// <param name="value"> The intended value of the property. </param>
/// <param name="attributes"> Attributes that indicate whether the property is writable,
/// configurable and enumerable. </param>
/// <param name="overwriteAttributes"> Indicates whether to overwrite any existing attributes. </param>
internal void FastSetProperty(string propertyName, object value, PropertyAttributes attributes = PropertyAttributes.Sealed, bool overwriteAttributes = false)
{
int index = this.schema.GetPropertyIndex(propertyName);
if (index < 0)
{
// The property is doesn't exist - add a new property.
AddProperty(propertyName, value, attributes, false);
return;
}
if (overwriteAttributes == true)
this.schema = this.schema.SetPropertyAttributes(propertyName, attributes);
this.propertyValues[index] = value;
}
/// <summary>
/// Adds a property to this object. The property must not already exist.
/// </summary>
/// <param name="propertyName"> The name of the property to add. </param>
/// <param name="value"> The desired value of the property. This can be a
/// <see cref="PropertyAccessorValue"/>. </param>
/// <param name="attributes"> Attributes describing how the property may be modified. </param>
/// <param name="throwOnError"> <c>true</c> to throw an exception if the property could not
/// be added (i.e. if the object is not extensible). </param>
/// <returns> <c>true</c> if the property was successfully added; <c>false</c> otherwise. </returns>
private bool AddProperty(string propertyName, object value, PropertyAttributes attributes, bool throwOnError)
{
// Make sure adding a property is allowed.
if (this.IsExtensible == false)
{
if (throwOnError == true)
throw new JavaScriptException(this.Engine, "TypeError", string.Format("The property '{0}' cannot be created as the object is not extensible.", propertyName));
return false;
}
// To avoid running out of memory, restrict the number of properties.
if (this.schema.PropertyCount == 16384)
throw new JavaScriptException(this.engine, "Error", "Maximum number of named properties reached.");
// Do not store nulls - null represents a non-existant value.
value = value ?? Undefined.Value;
// Add a new property to the schema.
this.schema = this.schema.AddProperty(propertyName, attributes);
// Check if the value array needs to be resized.
int propertyIndex = this.schema.NextValueIndex - 1;
if (propertyIndex >= this.InlinePropertyValues.Length)
Array.Resize(ref this.propertyValues, this.InlinePropertyValues.Length * 2);
// Set the value of the property.
this.propertyValues[propertyIndex] = value;
// Success.
return true;
}
/// <summary>
/// Defines or redefines the value and attributes of a property. The prototype chain is
/// not searched so if the property exists but only in the prototype chain a new property
/// will be created.
/// </summary>
/// <param name="propertyName"> The name of the property to modify. </param>
/// <param name="descriptor"> The property value and attributes. </param>
/// <param name="throwOnError"> <c>true</c> to throw an exception if the property could not
/// be set. This can happen if the property is not configurable or the object is sealed. </param>
/// <returns> <c>true</c> if the property was successfully modified; <c>false</c> otherwise. </returns>
public virtual bool DefineProperty(string propertyName, PropertyDescriptor descriptor, bool throwOnError)
{
// Retrieve info on the property.
var current = this.schema.GetPropertyIndexAndAttributes(propertyName);
if (current.Exists == false)
{
// Create a new property.
return AddProperty(propertyName, descriptor.Value, descriptor.Attributes, throwOnError);
}
// If the current property is not configurable, then the only change that is allowed is
// a change from one simple value to another (i.e. accessors are not allowed) and only
// if the writable attribute is set.
if (current.IsConfigurable == false)
{
// Get the current value of the property.
object currentValue = this.propertyValues[current.Index];
object getter = null, setter = null;
if (currentValue is PropertyAccessorValue)
{
getter = ((PropertyAccessorValue)currentValue).Getter;
setter = ((PropertyAccessorValue)currentValue).Setter;
}
// Check if the modification is allowed.
if (descriptor.Attributes != current.Attributes ||
(descriptor.IsAccessor == true && (getter != descriptor.Getter || setter != descriptor.Setter)) ||
(descriptor.IsAccessor == false && current.IsWritable == false && TypeComparer.SameValue(currentValue, descriptor.Value) == false))
{
if (throwOnError == true)
throw new JavaScriptException(this.Engine, "TypeError", string.Format("The property '{0}' is non-configurable.", propertyName));
return false;
}
}
// Set the property value and attributes.
this.schema = this.schema.SetPropertyAttributes(propertyName, descriptor.Attributes);
this.propertyValues[current.Index] = descriptor.Value;
return true;
}
/// <summary>
/// Deletes the property with the given name.
/// </summary>
/// <param name="propertyName"> The name of the property to delete. </param>
/// <param name="throwOnError"> <c>true</c> to throw an exception if the property could not
/// be set because the property was marked as non-configurable. </param>
/// <returns> <c>true</c> if the property was successfully deleted, or if the property did
/// not exist; <c>false</c> if the property was marked as non-configurable and
/// <paramref name="throwOnError"/> was <c>false</c>. </returns>
public bool Delete(string propertyName, bool throwOnError)
{
// Check if the property is an indexed property.
uint arrayIndex = ArrayInstance.ParseArrayIndex(propertyName);
if (arrayIndex != uint.MaxValue)
return Delete(arrayIndex, throwOnError);
// Retrieve the attributes for the property.
var propertyInfo = this.schema.GetPropertyIndexAndAttributes(propertyName);
if (propertyInfo.Exists == false)
return true; // Property doesn't exist - delete succeeded!
// Check if the property can be deleted.
if (propertyInfo.IsConfigurable == false)
{
if (throwOnError == true)
throw new JavaScriptException(this.Engine, "TypeError", string.Format("The property '{0}' cannot be deleted.", propertyName));
return false;
}
// Delete the property.
this.schema = this.schema.DeleteProperty(propertyName);
return true;
}
/// <summary>
/// Sets up multiple properties at once.
/// </summary>
/// <param name="properties"> The list of properties to set. </param>
internal void FastSetProperties(IEnumerable<PropertyNameAndValue> properties)
{
if (this.schema.NextValueIndex != 0)
throw new InvalidOperationException("This method can only be called on a virgin object (one with no properties).");
if (this.propertyValues.Length < properties.Count())
this.propertyValues = new object[properties.Count()];
var propertyDictionary = new Dictionary<object, SchemaProperty>(properties.Count());
int nextValueIndex = 0;
foreach (var property in properties)
{
this.propertyValues[nextValueIndex] = property.Value;
propertyDictionary.Add(property.Key, new SchemaProperty(nextValueIndex++, property.Attributes));
}
this.schema = new HiddenClassSchema(propertyDictionary, nextValueIndex);
}
/// <summary>
/// Enumerates the property names and values for this schema.
/// </summary>
/// <param name="values"> The array containing the property values. </param>
/// <returns> An enumerable collection of property names and values. </returns>
public IEnumerable<PropertyNameAndValue> EnumeratePropertyNamesAndValues(object[] values)
{
if (this.properties == null)
this.properties = CreatePropertiesDictionary();
this.parent = null; // Prevents the properties dictionary from being stolen while an enumeration is in progress.
foreach (var pair in this.properties)
yield return new PropertyNameAndValue(pair.Key, new PropertyDescriptor(values[pair.Value.Index], pair.Value.Attributes));
}
/// <summary>
/// Creates a new HiddenClassSchema instance from an add operation.
/// </summary>
private HiddenClassSchema(Dictionary <object, SchemaProperty> properties, int nextValueIndex, HiddenClassSchema parent, TransitionInfo addPropertyTransitionInfo)
: this(properties, nextValueIndex)
{
this.parent = parent;
this.addPropertyTransitionInfo = addPropertyTransitionInfo;
}
/// <summary>
/// Caches property details.
/// </summary>
/// <param name="schema"> A reference to a schema that defines how properties are stored. </param>
/// <param name="index"> The index into the property array. </param>
internal void CachePropertyDetails(HiddenClassSchema schema, int index)
{
this.CachedSchema = schema;
this.CachedIndex = index;
}
/// <summary>
/// Deletes the property with the given array index.
/// </summary>
/// <param name="index"> The array index of the property to delete. </param>
/// <param name="throwOnError"> <c>true</c> to throw an exception if the property could not
/// be set because the property was marked as non-configurable. </param>
/// <returns> <c>true</c> if the property was successfully deleted, or if the property did
/// not exist; <c>false</c> if the property was marked as non-configurable and
/// <paramref name="throwOnError"/> was <c>false</c>. </returns>
public virtual bool Delete(uint index, bool throwOnError)
{
string indexStr = index.ToString();
// Retrieve the attributes for the property.
var propertyInfo = this.schema.GetPropertyIndexAndAttributes(indexStr);
if (propertyInfo.Exists == false)
return true; // Property doesn't exist - delete succeeded!
// Delete the property.
this.schema = this.schema.DeleteProperty(indexStr);
return true;
}
