1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
#pragma warning disable RS0030 // Do not use banned APIs
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using Jellyfin.Database.Implementations.Entities;
using Microsoft.EntityFrameworkCore;
namespace Jellyfin.Database.Implementations;
/// <summary>
/// Contains a number of query related extensions.
/// </summary>
public static class JellyfinQueryHelperExtensions
{
private static readonly MethodInfo _containsMethodGenericCache = typeof(Enumerable).GetMethods(BindingFlags.Public | BindingFlags.Static).First(m => m.Name == nameof(Enumerable.Contains) && m.GetParameters().Length == 2);
private static readonly MethodInfo _efParameterInstruction = typeof(EF).GetMethod(nameof(EF.Parameter), BindingFlags.Public | BindingFlags.Static)!;
private static readonly ConcurrentDictionary<Type, MethodInfo> _containsQueryCache = new();
/// <summary>
/// Builds an optimised query checking one property against a list of values while maintaining an optimal query.
/// </summary>
/// <typeparam name="TEntity">The entity.</typeparam>
/// <typeparam name="TProperty">The property type to compare.</typeparam>
/// <param name="query">The source query.</param>
/// <param name="oneOf">The list of items to check.</param>
/// <param name="property">Property expression.</param>
/// <returns>A Query.</returns>
public static IQueryable<TEntity> WhereOneOrMany<TEntity, TProperty>(this IQueryable<TEntity> query, IList<TProperty> oneOf, Expression<Func<TEntity, TProperty>> property)
{
return query.Where(OneOrManyExpressionBuilder(oneOf, property));
}
/// <summary>
/// Builds a query that checks referenced ItemValues for a cross BaseItem lookup.
/// </summary>
/// <param name="baseQuery">The source query.</param>
/// <param name="context">The database context.</param>
/// <param name="itemValueType">The type of item value to reference.</param>
/// <param name="referenceIds">The list of BaseItem ids to check matches.</param>
/// <param name="invert">If set an exclusion check is performed instead.</param>
/// <returns>A Query.</returns>
public static IQueryable<BaseItemEntity> WhereReferencedItem(
this IQueryable<BaseItemEntity> baseQuery,
JellyfinDbContext context,
ItemValueType itemValueType,
IList<Guid> referenceIds,
bool invert = false)
{
return baseQuery.Where(ReferencedItemFilterExpressionBuilder(context, itemValueType, referenceIds, invert));
}
/// <summary>
/// Builds a query expression that checks referenced ItemValues for a cross BaseItem lookup.
/// </summary>
/// <param name="context">The database context.</param>
/// <param name="itemValueType">The type of item value to reference.</param>
/// <param name="referenceIds">The list of BaseItem ids to check matches.</param>
/// <param name="invert">If set an exclusion check is performed instead.</param>
/// <returns>A Query.</returns>
public static Expression<Func<BaseItemEntity, bool>> ReferencedItemFilterExpressionBuilder(
this JellyfinDbContext context,
ItemValueType itemValueType,
IList<Guid> referenceIds,
bool invert = false)
{
// Well genre/artist/album etc items do not actually set the ItemValue of thier specitic types so we cannot match it that way.
/*
"(guid in (select itemid from ItemValues where CleanValue = (select CleanName from TypedBaseItems where guid=@GenreIds and Type=2)))"
*/
var itemFilter = OneOrManyExpressionBuilder<BaseItemEntity, Guid>(referenceIds, f => f.Id);
return item =>
context.ItemValues
.Join(context.ItemValuesMap, e => e.ItemValueId, e => e.ItemValueId, (item, map) => new { item, map })
.Any(val =>
val.item.Type == itemValueType
&& context.BaseItems.Where(itemFilter).Any(e => e.CleanName == val.item.CleanValue)
&& val.map.ItemId == item.Id) == EF.Constant(!invert);
}
/// <summary>
/// Builds an optimised query expression checking one property against a list of values while maintaining an optimal query.
/// </summary>
/// <typeparam name="TEntity">The entity.</typeparam>
/// <typeparam name="TProperty">The property type to compare.</typeparam>
/// <param name="oneOf">The list of items to check.</param>
/// <param name="property">Property expression.</param>
/// <returns>A Query.</returns>
public static Expression<Func<TEntity, bool>> OneOrManyExpressionBuilder<TEntity, TProperty>(this IList<TProperty> oneOf, Expression<Func<TEntity, TProperty>> property)
{
var parameter = Expression.Parameter(typeof(TEntity), "item");
property = ParameterReplacer.Replace<Func<TEntity, TProperty>, Func<TEntity, TProperty>>(property, property.Parameters[0], parameter);
if (oneOf.Count == 1)
{
var value = oneOf[0];
if (typeof(TProperty).IsValueType)
{
return Expression.Lambda<Func<TEntity, bool>>(Expression.Equal(property.Body, Expression.Constant(value)), parameter);
}
else
{
return Expression.Lambda<Func<TEntity, bool>>(Expression.ReferenceEqual(property.Body, Expression.Constant(value)), parameter);
}
}
var containsMethodInfo = _containsQueryCache.GetOrAdd(typeof(TProperty), static (key) => _containsMethodGenericCache.MakeGenericMethod(key));
if (oneOf.Count < 4) // arbitrary value choosen.
{
// if we have 3 or fewer values to check against its faster to do a IN(const,const,const) lookup
return Expression.Lambda<Func<TEntity, bool>>(Expression.Call(null, containsMethodInfo, Expression.Constant(oneOf), property.Body), parameter);
}
return Expression.Lambda<Func<TEntity, bool>>(Expression.Call(null, containsMethodInfo, Expression.Call(null, _efParameterInstruction.MakeGenericMethod(oneOf.GetType()), Expression.Constant(oneOf)), property.Body), parameter);
}
internal static class ParameterReplacer
{
// Produces an expression identical to 'expression'
// except with 'source' parameter replaced with 'target' expression.
internal static Expression<TOutput> Replace<TInput, TOutput>(
Expression<TInput> expression,
ParameterExpression source,
ParameterExpression target)
{
return new ParameterReplacerVisitor<TOutput>(source, target)
.VisitAndConvert(expression);
}
private sealed class ParameterReplacerVisitor<TOutput> : ExpressionVisitor
{
private readonly ParameterExpression _source;
private readonly ParameterExpression _target;
public ParameterReplacerVisitor(ParameterExpression source, ParameterExpression target)
{
_source = source;
_target = target;
}
internal Expression<TOutput> VisitAndConvert<T>(Expression<T> root)
{
return (Expression<TOutput>)VisitLambda(root);
}
protected override Expression VisitLambda<T>(Expression<T> node)
{
// Leave all parameters alone except the one we want to replace.
var parameters = node.Parameters.Select(p => p == _source ? _target : p);
return Expression.Lambda<TOutput>(Visit(node.Body), parameters);
}
protected override Expression VisitParameter(ParameterExpression node)
{
// Replace the source with the target, visit other params as usual.
return node == _source ? _target : base.VisitParameter(node);
}
}
}
}
|
