RaspberryIO/Unosquare.Swan.Lite/Components/ObjectMapper.cs

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C#
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2019-02-17 14:08:57 +01:00
namespace Unosquare.Swan.Components
{
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Abstractions;
/// <summary>
/// Represents an AutoMapper-like object to map from one object type
/// to another using defined properties map or using the default behaviour
/// to copy same named properties from one object to another.
///
/// The extension methods like CopyPropertiesTo use the default behaviour.
/// </summary>
/// <example>
/// The following code explains how to map an object's properties into an instance of type T.
/// <code>
/// using Unosquare.Swan
///
/// class Example
/// {
/// class Person
/// {
/// public string Name { get; set; }
/// public int Age { get; set; }
/// }
///
/// static void Main()
/// {
/// var obj = new { Name = "Søren", Age = 42 };
///
/// var person = Runtime.ObjectMapper.Map&lt;Person&gt;(obj);
/// }
/// }
/// </code>
/// The following code explains how to explicitly map certain properties.
/// <code>
/// using Unosquare.Swan
///
/// class Example
/// {
/// class User
/// {
/// public string Name { get; set; }
/// public Role Role { get; set; }
/// }
///
/// public class Role
/// {
/// public string Name { get; set; }
/// }
///
/// class UserDto
/// {
/// public string Name { get; set; }
/// public string Role { get; set; }
/// }
///
/// static void Main()
/// {
/// // create a User object
/// var person =
/// new User { Name = "Phillip", Role = new Role { Name = "Admin" } };
///
/// // create an Object Mapper
/// var mapper = new ObjectMapper();
///
/// // map the User's Role.Name to UserDto's Role
/// mapper.CreateMap&lt;User, UserDto&gt;()
/// .MapProperty(d => d.Role, x => x.Role.Name);
///
/// // apply the previous map and retrieve a UserDto object
/// var destination = mapper.Map&lt;UserDto&gt;(person);
/// }
/// }
/// </code>
/// </example>
public class ObjectMapper
{
private readonly List<IObjectMap> _maps = new List<IObjectMap>();
/// <summary>
/// Copies the specified source.
/// </summary>
/// <param name="source">The source.</param>
/// <param name="target">The target.</param>
/// <param name="propertiesToCopy">The properties to copy.</param>
/// <param name="ignoreProperties">The ignore properties.</param>
/// <returns>
/// Copied properties count.
/// </returns>
/// <exception cref="ArgumentNullException">
/// source
/// or
/// target.
/// </exception>
public static int Copy(
object source,
object target,
string[] propertiesToCopy = null,
string[] ignoreProperties = null)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (target == null)
throw new ArgumentNullException(nameof(target));
return Copy(
target,
propertiesToCopy,
ignoreProperties,
GetSourceMap(source));
}
/// <summary>
/// Copies the specified source.
/// </summary>
/// <param name="source">The source.</param>
/// <param name="target">The target.</param>
/// <param name="propertiesToCopy">The properties to copy.</param>
/// <param name="ignoreProperties">The ignore properties.</param>
/// <returns>
/// Copied properties count.
/// </returns>
/// <exception cref="ArgumentNullException">
/// source
/// or
/// target.
/// </exception>
public static int Copy(
IDictionary<string, object> source,
object target,
string[] propertiesToCopy = null,
string[] ignoreProperties = null)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (target == null)
throw new ArgumentNullException(nameof(target));
return Copy(
target,
propertiesToCopy,
ignoreProperties,
source.ToDictionary(
x => x.Key.ToLowerInvariant(),
x => new TypeValuePair(typeof(object), x.Value)));
}
/// <summary>
/// Creates the map.
/// </summary>
/// <typeparam name="TSource">The type of the source.</typeparam>
/// <typeparam name="TDestination">The type of the destination.</typeparam>
/// <returns>
/// An object map representation of type of the destination property
/// and type of the source property.
/// </returns>
/// <exception cref="System.InvalidOperationException">
/// You can't create an existing map
/// or
/// Types doesn't match.
/// </exception>
public ObjectMap<TSource, TDestination> CreateMap<TSource, TDestination>()
{
if (_maps.Any(x => x.SourceType == typeof(TSource) && x.DestinationType == typeof(TDestination)))
{
throw new InvalidOperationException("You can't create an existing map");
}
var sourceType = Runtime.PropertyTypeCache.RetrieveAllProperties<TSource>(true);
var destinationType = Runtime.PropertyTypeCache.RetrieveAllProperties<TDestination>(true);
var intersect = sourceType.Intersect(destinationType, new PropertyInfoComparer()).ToArray();
if (intersect.Any() == false)
{
throw new InvalidOperationException("Types doesn't match");
}
var map = new ObjectMap<TSource, TDestination>(intersect);
_maps.Add(map);
return map;
}
/// <summary>
/// Maps the specified source.
/// </summary>
/// <typeparam name="TDestination">The type of the destination.</typeparam>
/// <param name="source">The source.</param>
/// <param name="autoResolve">if set to <c>true</c> [automatic resolve].</param>
/// <returns>
/// A new instance of the map.
/// </returns>
/// <exception cref="ArgumentNullException">source.</exception>
/// <exception cref="InvalidOperationException">You can't map from type {source.GetType().Name} to {typeof(TDestination).Name}.</exception>
public TDestination Map<TDestination>(object source, bool autoResolve = true)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
var destination = Activator.CreateInstance<TDestination>();
var map = _maps
.FirstOrDefault(x => x.SourceType == source.GetType() && x.DestinationType == typeof(TDestination));
if (map != null)
{
foreach (var property in map.Map)
{
var finalSource = property.Value.Aggregate(source,
(current, sourceProperty) => sourceProperty.GetValue(current));
property.Key.SetValue(destination, finalSource);
}
}
else
{
if (!autoResolve)
{
throw new InvalidOperationException(
$"You can't map from type {source.GetType().Name} to {typeof(TDestination).Name}");
}
// Missing mapping, try to use default behavior
Copy(source, destination);
}
return destination;
}
private static int Copy(
object target,
IEnumerable<string> propertiesToCopy,
IEnumerable<string> ignoreProperties,
Dictionary<string, TypeValuePair> sourceProperties)
{
// Filter properties
var requiredProperties = propertiesToCopy?
.Where(p => !string.IsNullOrWhiteSpace(p))
.Select(p => p.ToLowerInvariant());
var ignoredProperties = ignoreProperties?
.Where(p => !string.IsNullOrWhiteSpace(p))
.Select(p => p.ToLowerInvariant());
var properties = Runtime.PropertyTypeCache
.RetrieveFilteredProperties(target.GetType(), true, x => x.CanWrite);
return properties
.Select(x => x.Name)
.Distinct()
.ToDictionary(x => x.ToLowerInvariant(), x => properties.First(y => y.Name == x))
.Where(x => sourceProperties.Keys.Contains(x.Key))
.When(() => requiredProperties != null, q => q.Where(y => requiredProperties.Contains(y.Key)))
.When(() => ignoredProperties != null, q => q.Where(y => !ignoredProperties.Contains(y.Key)))
.ToDictionary(x => x.Value, x => sourceProperties[x.Key])
.Sum(x => TrySetValue(x, target) ? 1 : 0);
}
private static bool TrySetValue(KeyValuePair<PropertyInfo, TypeValuePair> property, object target)
{
try
{
SetValue(property, target);
return true;
}
catch
{
// swallow
}
return false;
}
private static void SetValue(KeyValuePair<PropertyInfo, TypeValuePair> property, object target)
{
if (property.Value.Type.GetTypeInfo().IsEnum)
{
property.Key.SetValue(target,
Enum.ToObject(property.Key.PropertyType, property.Value.Value));
return;
}
if (!property.Value.Type.IsValueType() && property.Key.PropertyType == property.Value.Type)
{
property.Key.SetValue(target, GetValue(property.Value.Value, property.Key.PropertyType));
return;
}
if (property.Key.PropertyType == typeof(bool))
{
property.Key.SetValue(target,
Convert.ToBoolean(property.Value.Value));
return;
}
property.Key.TrySetBasicType(property.Value.Value, target);
}
private static object GetValue(object source, Type targetType)
{
if (source == null)
return null;
object target = null;
source.CreateTarget(targetType, false, ref target);
switch (source)
{
case string _:
target = source;
break;
case IList sourceList when target is Array targetArray:
for (var i = 0; i < sourceList.Count; i++)
{
try
{
targetArray.SetValue(
sourceList[i].GetType().IsValueType()
? sourceList[i]
: sourceList[i].CopyPropertiesToNew<object>(), i);
}
catch
{
// ignored
}
}
break;
case IList sourceList when target is IList targetList:
var addMethod = targetType.GetMethods()
.FirstOrDefault(
m => m.Name.Equals(Formatters.Json.AddMethodName) && m.IsPublic &&
m.GetParameters().Length == 1);
if (addMethod == null) return target;
foreach (var item in sourceList)
{
try
{
targetList.Add(item.GetType().IsValueType()
? item
: item.CopyPropertiesToNew<object>());
}
catch
{
// ignored
}
}
break;
default:
source.CopyPropertiesTo(target);
break;
}
return target;
}
private static Dictionary<string, TypeValuePair> GetSourceMap(object source)
{
// select distinct properties because they can be duplicated by inheritance
var sourceProperties = Runtime.PropertyTypeCache
.RetrieveFilteredProperties(source.GetType(), true, x => x.CanRead)
.ToArray();
return sourceProperties
.Select(x => x.Name)
.Distinct()
.ToDictionary(
x => x.ToLowerInvariant(),
x => new TypeValuePair(sourceProperties.First(y => y.Name == x).PropertyType,
sourceProperties.First(y => y.Name == x).GetValue(source)));
}
internal class TypeValuePair
{
public TypeValuePair(Type type, object value)
{
Type = type;
Value = value;
}
public Type Type { get; }
public object Value { get; }
}
internal class PropertyInfoComparer : IEqualityComparer<PropertyInfo>
{
public bool Equals(PropertyInfo x, PropertyInfo y)
=> x != null && y != null && x.Name == y.Name && x.PropertyType == y.PropertyType;
public int GetHashCode(PropertyInfo obj)
=> obj.Name.GetHashCode() + obj.PropertyType.Name.GetHashCode();
}
}
}