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@Ivony
Ivony committed Oct 15, 2012
1 parent 988611f commit 3b49e9e
Showing 1 changed file with 198 additions and 198 deletions.
396 changes: 198 additions & 198 deletions Sources/Ivony.Data/EntityExtensions.cs
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@@ -1,200 +1,200 @@
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
using System.Text;

namespace Ivony.Data
{
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
using System.Text;

namespace Ivony.Data
{
/// <summary>
/// 提供面向 Entity 的扩展方法
/// </summary>
public static class EntityExtensions
{



/// <summary>
/// 查询数据库并将最后一个结果集填充实体类型
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dbUtility">DbUtility 实例</param>
/// <param name="expression">查询表达式</param>
/// <returns>实体集</returns>
public static T[] Entities<T>( this DbUtility dbUtility, IDbExpression expression ) where T : new()
{
var data = dbUtility.Data( expression );
return data.Rows.Cast<DataRow>().Select( dataItem => dataItem.ToEntity<T>() ).ToArray();
}


/// <summary>
/// 查询数据库并将结果首行填充实体
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dbUtility">DbUtility 实例</param>
/// <param name="expression">查询表达式</param>
/// <returns>实体</returns>
public static T Entity<T>( this DbUtility dbUtility, IDbExpression expression ) where T : new()
{
var dataItem = dbUtility.FirstRow( expression );
return dataItem.ToEntity<T>();
}


/// <summary>
/// 将 DataRow 转换为实体
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dataItem">包含数据的 DataRow</param>
/// <returns>实体</returns>
public static T ToEntity<T>( this DataRow dataItem ) where T : new()
{
var method = CreateEntityConverter<T>();
var entity = new T();
method( dataItem, entity );
return entity;
}

private static Action<DataRow, T> CreateEntityConverter<T>()
{
var method = ConverterCache<T>.Converter;
if ( method != null )
return method;

var type = typeof( T );
var properties = type.GetProperties()
.Where( p => !GetAttributes( p ).OfType<NonFieldAttribute>().Any() );

var methodName = type.GUID.ToString( "N" ) + "_DataConverter";
var dynamicMethod = new DynamicMethod( methodName, null, new[] { typeof( DataRow ), type }, typeof( EntityExtensions ) );
var il = dynamicMethod.GetILGenerator();

/*
.maxstack 3
.locals init ([0] class [System.Data]System.Data.DataColumnCollection columns)
IL_0000: ldarg.0
IL_0001: callvirt instance class [System.Data]System.Data.DataTable [System.Data]System.Data.DataRow::get_Table()
IL_0006: callvirt instance class [System.Data]System.Data.DataColumnCollection [System.Data]System.Data.DataTable::get_Columns()
IL_000b: stloc.0
*/

il.DeclareLocal( typeof( DataColumnCollection ) );
il.Emit( OpCodes.Ldarg_0 );
il.Emit( OpCodes.Callvirt, typeof( DataRow ).GetProperty( "Table" ).GetGetMethod() );
il.Emit( OpCodes.Callvirt, typeof( DataTable ).GetProperty( "Columns" ).GetGetMethod() );
il.Emit( OpCodes.Stloc_0 );


foreach ( var p in properties )
{
var name = GetFieldname( p );

/*
IL_000c: ldloc.0
IL_000d: ldstr "Name"
IL_0012: callvirt instance bool [System.Data]System.Data.DataColumnCollection::Contains(string)
IL_0017: brfalse.s IL_002a
IL_0019: ldarg.1
IL_001a: ldarg.0
IL_001b: ldstr "Name"
IL_0020: call !!0 [System.Data.DataSetExtensions]System.Data.DataRowExtensions::Field<string>(class [System.Data]System.Data.DataRow, string)
IL_0025: callvirt instance void Ivony.Data.EntityExtensions/TestEntity::set_Name(string)
IL_002a: ret
*/

var label = il.DefineLabel();

il.Emit( OpCodes.Ldloc_0 );
il.Emit( OpCodes.Ldstr, name );
il.Emit( OpCodes.Callvirt, typeof( DataColumnCollection ).GetMethod( "Contains" ) );
il.Emit( OpCodes.Brfalse_S, label );
il.Emit( OpCodes.Ldarg_1 );
il.Emit( OpCodes.Ldarg_0 );
il.Emit( OpCodes.Ldstr, name );
il.Emit( OpCodes.Call, typeof( DataRowExtensions ).GetMethod( "Field", new[] { typeof( DataRow ), typeof( string ) } ).MakeGenericMethod( p.PropertyType ) );
il.Emit( OpCodes.Callvirt, p.GetSetMethod() );
il.MarkLabel( label );
}

il.Emit( OpCodes.Ret );

method = (Action<DataRow, T>) dynamicMethod.CreateDelegate( typeof( Action<DataRow, T> ) );
ConverterCache<T>.Converter = method;
return method;
}

private static string GetFieldname( PropertyInfo p )
{
var attribute = GetAttributes( p ).OfType<FieldNameAttribute>().FirstOrDefault();

if ( attribute != null )
return attribute.FieldName;

return p.Name;
}


private static object sync = new object();
private static Dictionary<PropertyInfo, object[]> _propertyAttributesCache = new Dictionary<PropertyInfo,object[]>();

private static object[] GetAttributes( PropertyInfo p )
{
lock ( sync )
{
object[] attributes;

if ( _propertyAttributesCache.TryGetValue( p, out attributes ) )
return attributes;

attributes = p.GetCustomAttributes( false );

_propertyAttributesCache[p] = attributes;

return attributes;
}
}

private static class ConverterCache<T>
{
public static Action<DataRow, T> Converter { get; set; }
}
}

/// <summary>
/// 用于指定字段名称的特性
/// </summary>
[AttributeUsage( AttributeTargets.Property, Inherited = false )]
public class FieldNameAttribute : Attribute
{
/// <summary>
/// 创建 FieldNameAttribute 对象
/// </summary>
/// <param name="name">字段名</param>
public FieldNameAttribute( string name )
{
FieldName = name;
}

/// <summary>
/// 字段名
/// </summary>
public string FieldName
{
get;
set;
}
}


/// <summary>
/// 用于指示属性与任何字段没有关系
/// </summary>
[AttributeUsage( AttributeTargets.Property, Inherited = false )]
public class NonFieldAttribute : Attribute
{
}

}
/// </summary>
public static class EntityExtensions
{



/// <summary>
/// 查询数据库并将最后一个结果集填充实体类型
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dbUtility">DbUtility 实例</param>
/// <param name="expression">查询表达式</param>
/// <returns>实体集</returns>
public static T[] Entities<T>( this DbUtility dbUtility, IDbExpression expression ) where T : new()
{
var data = dbUtility.Data( expression );
return data.Rows.Cast<DataRow>().Select( dataItem => dataItem.ToEntity<T>() ).ToArray();
}


/// <summary>
/// 查询数据库并将结果首行填充实体
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dbUtility">DbUtility 实例</param>
/// <param name="expression">查询表达式</param>
/// <returns>实体</returns>
public static T Entity<T>( this DbUtility dbUtility, IDbExpression expression ) where T : new()
{
var dataItem = dbUtility.FirstRow( expression );
return dataItem.ToEntity<T>();
}


/// <summary>
/// 将 DataRow 转换为实体
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dataItem">包含数据的 DataRow</param>
/// <returns>实体</returns>
public static T ToEntity<T>( this DataRow dataItem ) where T : new()
{
var method = CreateEntityConverter<T>();
var entity = new T();
method( dataItem, entity );
return entity;
}

private static Action<DataRow, T> CreateEntityConverter<T>()
{
var method = ConverterCache<T>.Converter;
if ( method != null )
return method;

var type = typeof( T );
var properties = type.GetProperties()
.Where( p => !GetAttributes( p ).OfType<NonFieldAttribute>().Any() );

var methodName = type.GUID.ToString( "N" ) + "_DataConverter";
var dynamicMethod = new DynamicMethod( methodName, null, new[] { typeof( DataRow ), type }, typeof( EntityExtensions ) );
var il = dynamicMethod.GetILGenerator();

/*
.maxstack 3
.locals init ([0] class [System.Data]System.Data.DataColumnCollection columns)
IL_0000: ldarg.0
IL_0001: callvirt instance class [System.Data]System.Data.DataTable [System.Data]System.Data.DataRow::get_Table()
IL_0006: callvirt instance class [System.Data]System.Data.DataColumnCollection [System.Data]System.Data.DataTable::get_Columns()
IL_000b: stloc.0
*/

il.DeclareLocal( typeof( DataColumnCollection ) );
il.Emit( OpCodes.Ldarg_0 );
il.Emit( OpCodes.Callvirt, typeof( DataRow ).GetProperty( "Table" ).GetGetMethod() );
il.Emit( OpCodes.Callvirt, typeof( DataTable ).GetProperty( "Columns" ).GetGetMethod() );
il.Emit( OpCodes.Stloc_0 );


foreach ( var p in properties )
{
var name = GetFieldname( p );

/*
IL_000c: ldloc.0
IL_000d: ldstr "Name"
IL_0012: callvirt instance bool [System.Data]System.Data.DataColumnCollection::Contains(string)
IL_0017: brfalse.s IL_002a
IL_0019: ldarg.1
IL_001a: ldarg.0
IL_001b: ldstr "Name"
IL_0020: call !!0 [System.Data.DataSetExtensions]System.Data.DataRowExtensions::Field<string>(class [System.Data]System.Data.DataRow, string)
IL_0025: callvirt instance void Ivony.Data.EntityExtensions/TestEntity::set_Name(string)
IL_002a: ret
*/

var label = il.DefineLabel();

il.Emit( OpCodes.Ldloc_0 );
il.Emit( OpCodes.Ldstr, name );
il.Emit( OpCodes.Callvirt, typeof( DataColumnCollection ).GetMethod( "Contains" ) );
il.Emit( OpCodes.Brfalse_S, label );
il.Emit( OpCodes.Ldarg_1 );
il.Emit( OpCodes.Ldarg_0 );
il.Emit( OpCodes.Ldstr, name );
il.Emit( OpCodes.Call, typeof( DataRowExtensions ).GetMethod( "Field", new[] { typeof( DataRow ), typeof( string ) } ).MakeGenericMethod( p.PropertyType ) );
il.Emit( OpCodes.Callvirt, p.GetSetMethod() );
il.MarkLabel( label );
}

il.Emit( OpCodes.Ret );

method = (Action<DataRow, T>) dynamicMethod.CreateDelegate( typeof( Action<DataRow, T> ) );
ConverterCache<T>.Converter = method;
return method;
}

private static string GetFieldname( PropertyInfo p )
{
var attribute = GetAttributes( p ).OfType<FieldNameAttribute>().FirstOrDefault();

if ( attribute != null )
return attribute.FieldName;

return p.Name;
}


private static object sync = new object();
private static Dictionary<PropertyInfo, object[]> _propertyAttributesCache = new Dictionary<PropertyInfo,object[]>();

private static object[] GetAttributes( PropertyInfo p )
{
lock ( sync )
{
object[] attributes;

if ( _propertyAttributesCache.TryGetValue( p, out attributes ) )
return attributes;

attributes = p.GetCustomAttributes( false );

_propertyAttributesCache[p] = attributes;

return attributes;
}
}

private static class ConverterCache<T>
{
public static Action<DataRow, T> Converter { get; set; }
}
}

/// <summary>
/// 用于指定字段名称的特性
/// </summary>
[AttributeUsage( AttributeTargets.Property, Inherited = false )]
public class FieldNameAttribute : Attribute
{
/// <summary>
/// 创建 FieldNameAttribute 对象
/// </summary>
/// <param name="name">字段名</param>
public FieldNameAttribute( string name )
{
FieldName = name;
}

/// <summary>
/// 字段名
/// </summary>
public string FieldName
{
get;
set;
}
}


/// <summary>
/// 用于指示属性与任何字段没有关系
/// </summary>
[AttributeUsage( AttributeTargets.Property, Inherited = false )]
public class NonFieldAttribute : Attribute
{
}

}

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