maui-linux/Xamarin.Forms.Xaml/CreateValuesVisitor.cs

392 строки
12 KiB
C#

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Xml;
using Xamarin.Forms.Internals;
using Xamarin.Forms.Xaml.Internals;
namespace Xamarin.Forms.Xaml
{
internal class CreateValuesVisitor : IXamlNodeVisitor
{
public CreateValuesVisitor(HydratationContext context)
{
Context = context;
}
Dictionary<INode, object> Values
{
get { return Context.Values; }
}
HydratationContext Context { get; }
public bool VisitChildrenFirst
{
get { return true; }
}
public bool StopOnDataTemplate
{
get { return true; }
}
public bool StopOnResourceDictionary
{
get { return false; }
}
public void Visit(ValueNode node, INode parentNode)
{
Values[node] = node.Value;
}
public void Visit(MarkupNode node, INode parentNode)
{
}
public void Visit(ElementNode node, INode parentNode)
{
object value = null;
XamlParseException xpe;
var type = XamlParser.GetElementType(node.XmlType, node, Context.RootElement?.GetType().GetTypeInfo().Assembly,
out xpe);
if (xpe != null)
throw xpe;
Context.Types[node] = type;
string ctorargname;
if (IsXaml2009LanguagePrimitive(node))
value = CreateLanguagePrimitive(type, node);
else if (node.Properties.ContainsKey(XmlName.xArguments) || node.Properties.ContainsKey(XmlName.xFactoryMethod))
value = CreateFromFactory(type, node);
else if (
type.GetTypeInfo()
.DeclaredConstructors.Any(
ci =>
ci.IsPublic && ci.GetParameters().Length != 0 &&
ci.GetParameters().All(pi => pi.CustomAttributes.Any(attr => attr.AttributeType == typeof (ParameterAttribute)))) &&
ValidateCtorArguments(type, node, out ctorargname))
value = CreateFromParameterizedConstructor(type, node);
else if (!type.GetTypeInfo().DeclaredConstructors.Any(ci => ci.IsPublic && ci.GetParameters().Length == 0) &&
!ValidateCtorArguments(type, node, out ctorargname))
{
throw new XamlParseException($"The Property {ctorargname} is required to create a {type.FullName} object.", node);
}
else
{
//this is a trick as the DataTemplate parameterless ctor is internal, and we can't CreateInstance(..., false) on WP7
try
{
if (type == typeof (DataTemplate))
value = new DataTemplate();
if (type == typeof (ControlTemplate))
value = new ControlTemplate();
if (value == null && node.CollectionItems.Any() && node.CollectionItems.First() is ValueNode)
{
var serviceProvider = new XamlServiceProvider(node, Context);
var converted = ((ValueNode)node.CollectionItems.First()).Value.ConvertTo(type, () => type.GetTypeInfo(),
serviceProvider);
if (converted != null && converted.GetType() == type)
value = converted;
}
if (value == null)
value = Activator.CreateInstance(type);
}
catch (TargetInvocationException e)
{
if (e.InnerException is XamlParseException || e.InnerException is XmlException)
throw e.InnerException;
throw;
}
}
Values[node] = value;
var markup = value as IMarkupExtension;
if (markup != null && (value is TypeExtension || value is StaticExtension || value is ArrayExtension))
{
var serviceProvider = new XamlServiceProvider(node, Context);
var visitor = new ApplyPropertiesVisitor(Context);
foreach (var cnode in node.Properties.Values.ToList())
cnode.Accept(visitor, node);
foreach (var cnode in node.CollectionItems)
cnode.Accept(visitor, node);
value = markup.ProvideValue(serviceProvider);
INode xKey;
if (!node.Properties.TryGetValue(XmlName.xKey, out xKey))
xKey = null;
node.Properties.Clear();
node.CollectionItems.Clear();
if (xKey != null)
node.Properties.Add(XmlName.xKey, xKey);
Values[node] = value;
}
if (value is BindableObject)
NameScope.SetNameScope(value as BindableObject, node.Namescope);
}
public void Visit(RootNode node, INode parentNode)
{
var rnode = (XamlLoader.RuntimeRootNode)node;
Values[node] = rnode.Root;
Context.Types[node] = rnode.Root.GetType();
var bindableRoot = rnode.Root as BindableObject;
if (bindableRoot != null)
NameScope.SetNameScope(bindableRoot, node.Namescope);
}
public void Visit(ListNode node, INode parentNode)
{
//this is a gross hack to keep ListNode alive. ListNode must go in favor of Properties
XmlName name;
if (ApplyPropertiesVisitor.TryGetPropertyName(node, parentNode, out name))
node.XmlName = name;
}
bool ValidateCtorArguments(Type nodeType, IElementNode node, out string missingArgName)
{
missingArgName = null;
var ctorInfo =
nodeType.GetTypeInfo()
.DeclaredConstructors.FirstOrDefault(
ci =>
ci.GetParameters().Length != 0 && ci.IsPublic &&
ci.GetParameters().All(pi => pi.CustomAttributes.Any(attr => attr.AttributeType == typeof (ParameterAttribute))));
if (ctorInfo == null)
return true;
foreach (var parameter in ctorInfo.GetParameters())
{
var propname =
parameter.CustomAttributes.First(ca => ca.AttributeType.FullName == "Xamarin.Forms.ParameterAttribute")
.ConstructorArguments.First()
.Value as string;
if (!node.Properties.ContainsKey(new XmlName("", propname)))
{
missingArgName = propname;
return false;
}
}
return true;
}
public object CreateFromParameterizedConstructor(Type nodeType, IElementNode node)
{
var ctorInfo =
nodeType.GetTypeInfo()
.DeclaredConstructors.FirstOrDefault(
ci =>
ci.GetParameters().Length != 0 && ci.IsPublic &&
ci.GetParameters().All(pi => pi.CustomAttributes.Any(attr => attr.AttributeType == typeof (ParameterAttribute))));
object[] arguments = CreateArgumentsArray(node, ctorInfo);
return ctorInfo.Invoke(arguments);
}
public object CreateFromFactory(Type nodeType, IElementNode node)
{
object[] arguments = CreateArgumentsArray(node);
if (!node.Properties.ContainsKey(XmlName.xFactoryMethod))
{
//non-default ctor
return Activator.CreateInstance(nodeType, arguments);
}
var factoryMethod = ((string)((ValueNode)node.Properties[XmlName.xFactoryMethod]).Value);
Type[] types = arguments == null ? new Type[0] : arguments.Select(a => a.GetType()).ToArray();
Func<MethodInfo, bool> isMatch = m => {
if (m.Name != factoryMethod)
return false;
var p = m.GetParameters();
if (p.Length != types.Length)
return false;
if (!m.IsStatic)
return false;
for (var i = 0; i < p.Length; i++) {
if ((p [i].ParameterType.IsAssignableFrom(types [i])))
continue;
var op_impl = p [i].ParameterType.GetRuntimeMethod("op_Implicit", new [] { types [i]});
if (op_impl == null)
return false;
arguments [i] = op_impl.Invoke(null, new [] { arguments [i]});
}
return true;
};
var mi = nodeType.GetRuntimeMethods().FirstOrDefault(isMatch);
if (mi == null)
throw new MissingMemberException($"No static method found for {nodeType.FullName}::{factoryMethod} ({string.Join(", ", types.Select(t => t.FullName))})");
return mi.Invoke(null, arguments);
}
public object[] CreateArgumentsArray(IElementNode enode)
{
if (!enode.Properties.ContainsKey(XmlName.xArguments))
return null;
var node = enode.Properties[XmlName.xArguments];
var elementNode = node as ElementNode;
if (elementNode != null)
{
var array = new object[1];
array[0] = Values[elementNode];
return array;
}
var listnode = node as ListNode;
if (listnode != null)
{
var array = new object[listnode.CollectionItems.Count];
for (var i = 0; i < listnode.CollectionItems.Count; i++)
array[i] = Values[(ElementNode)listnode.CollectionItems[i]];
return array;
}
return null;
}
public object[] CreateArgumentsArray(IElementNode enode, ConstructorInfo ctorInfo)
{
var n = ctorInfo.GetParameters().Length;
var array = new object[n];
for (var i = 0; i < n; i++)
{
var parameter = ctorInfo.GetParameters()[i];
var propname =
parameter.CustomAttributes.First(attr => attr.AttributeType == typeof (ParameterAttribute))
.ConstructorArguments.First()
.Value as string;
var name = new XmlName("", propname);
INode node;
if (!enode.Properties.TryGetValue(name, out node))
{
throw new XamlParseException(
String.Format("The Property {0} is required to create a {1} object.", propname, ctorInfo.DeclaringType.FullName),
enode as IXmlLineInfo);
}
if (!enode.SkipProperties.Contains(name))
enode.SkipProperties.Add(name);
var value = Context.Values[node];
var serviceProvider = new XamlServiceProvider(enode, Context);
var convertedValue = value.ConvertTo(parameter.ParameterType, () => parameter, serviceProvider);
array[i] = convertedValue;
}
return array;
}
static bool IsXaml2009LanguagePrimitive(IElementNode node)
{
return node.NamespaceURI == "http://schemas.microsoft.com/winfx/2009/xaml";
}
static object CreateLanguagePrimitive(Type nodeType, IElementNode node)
{
object value = null;
if (nodeType == typeof (string))
value = String.Empty;
else if (nodeType == typeof (Uri))
value = null;
else
value = Activator.CreateInstance(nodeType);
if (node.CollectionItems.Count == 1 && node.CollectionItems[0] is ValueNode &&
((ValueNode)node.CollectionItems[0]).Value is string)
{
var valuestring = ((ValueNode)node.CollectionItems[0]).Value as string;
if (nodeType == typeof(SByte)) {
sbyte retval;
if (sbyte.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(Int16)) {
short retval;
if (short.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(Int32)) {
int retval;
if (int.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(Int64)) {
long retval;
if (long.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(Byte)) {
byte retval;
if (byte.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(UInt16)) {
ushort retval;
if (ushort.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(UInt32)) {
uint retval;
if (uint.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(UInt64)) {
ulong retval;
if (ulong.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(Single)) {
float retval;
if (float.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof(Double)) {
double retval;
if (double.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof (Boolean))
{
bool outbool;
if (bool.TryParse(valuestring, out outbool))
return outbool;
}
if (nodeType == typeof(TimeSpan)) {
TimeSpan retval;
if (TimeSpan.TryParse(valuestring, CultureInfo.InvariantCulture, out retval))
return retval;
}
if (nodeType == typeof (char))
{
char retval;
if (char.TryParse(valuestring, out retval))
return retval;
}
if (nodeType == typeof (string))
return valuestring;
if (nodeType == typeof (decimal))
{
decimal retval;
if (decimal.TryParse(valuestring, NumberStyles.Number, CultureInfo.InvariantCulture, out retval))
return retval;
}
else if (nodeType == typeof (Uri))
{
Uri retval;
if (Uri.TryCreate(valuestring, UriKind.RelativeOrAbsolute, out retval))
return retval;
}
}
return value;
}
}
}