/// <summary>
/// <typeparamref name="TEntity"/> の述語デリゲートを作成します。
/// 既定の実装では <see cref="Create(TContext, ref bool)"/> に処理を委譲します。
/// </summary>
/// <param name="context">パイプラインの実行時コンテキスト。常に非 <c>null</c>。</param>
/// <param name="next">パイプラインの後続のコンポーネントを表すデリゲート。常に非 <c>null</c>。呼ばない事により残りのコンポーネントをショートサーキットできます。</param>
/// <returns>このコンポーネント以降の述語処理を表すデリゲート。常に非 <c>null</c>。</returns>
protected virtual Task <PredicateFunc <TEntity> > CreateAsync(TContext context, Func <TContext, Task <PredicateFunc <TEntity> > > next)
{
Debug.Assert(context != null);
Debug.Assert(next != null);
var cancelled = false;
PredicateFunc <TEntity> predicate = Create(context, ref cancelled);
Debug.Assert(predicate != null);
if (cancelled)
{
return(Task.FromResult(predicate));
}
if (predicate == NullPredicate)
{
return(next(context));
}
return(InternalAsync());
async Task <PredicateFunc <TEntity> > InternalAsync()
{
PredicateFunc <TEntity> nextPredicate = await next(context).ConfigureAwait(false);
Debug.Assert(nextPredicate != null);
if (nextPredicate == NullPredicate)
{
return(predicate);
}
return(x => predicate(x) && nextPredicate(x));
}
}
public void CreateAsync_Cancelled()
{
PredicateFunc <DummyEntity> createResult = _ => Rand.Bool();
var middleware = new SpyPredicateMiddlewareToCreateAsync(createResult, cancelled: true);
var context = new DummyContext();
Func <DummyContext, Task <PredicateFunc <DummyEntity> > > next = _ => throw new AssertFailedException("next は呼ばれてはいけません。");
new TestCaseRunner()
.Run(() => middleware.CreateAsync(context, next))
.Verify((actual, desc) => {
Assert.AreEqual(createResult, actual, desc);
Assert.AreEqual(context, middleware.ActualContext, desc);
Assert.AreEqual(false, middleware.ActualCancelled, desc);
}, (Type)null);
}
public void Invoke()
{
PredicateFunc <DummyEntity> createAsyncResult = _ => Rand.Bool();
var middleware = new SpyPredicateMiddlewareToMiddleware(createAsyncResult);
Func <DummyContext, Task <PredicateFunc <DummyEntity> > > next = _ => Task.FromResult <PredicateFunc <DummyEntity> >(__ => Rand.Bool());
var context = new DummyContext();
new TestCaseRunner()
.Run(() => middleware.Invoke(next)(context))
.Verify((actual, desc) => {
Assert.AreEqual(createAsyncResult, actual, desc);
Assert.AreEqual(context, middleware.ActualContext, desc);
Assert.AreEqual(next, middleware.ActualNext, desc);
}, (Type)null);
}
public void CreateAsync_NullNextPredicate()
{
PredicateFunc <DummyEntity> createResult = _ => Rand.Bool();
var middleware = new SpyPredicateMiddlewareToCreateAsync(createResult, cancelled: false);
var context = new DummyContext();
DummyContext actualNextContext = default;
Func <DummyContext, Task <PredicateFunc <DummyEntity> > > next = ctx => {
actualNextContext = ctx;
return(Task.FromResult(SpyPredicateMiddlewareToCreateAsync.NullPredicate));
};
new TestCaseRunner()
.Run(() => middleware.CreateAsync(context, next))
.Verify((actual, desc) => {
Assert.AreEqual(createResult, actual, desc);
Assert.AreEqual(context, middleware.ActualContext, desc);
Assert.AreEqual(false, middleware.ActualCancelled, desc);
Assert.AreEqual(context, actualNextContext, desc);
}, (Type)null);
}
/// <summary>
/// <see cref="IMiddleware{T, TResult}.Invoke(Func{T, TResult})"/> の実装。
/// </summary>
public Func <TContext, Task <FilterFunc <TEntity> > > Invoke(Func <TContext, Task <FilterFunc <TEntity> > > next)
{
Debug.Assert(next != null);
return(async context => {
Debug.Assert(context != null);
PredicateFunc <TEntity> predicate = await _predicateCreator(context).ConfigureAwait(false);
Debug.Assert(predicate != null);
FilterFunc <TEntity> nextFilter = await next(context).ConfigureAwait(false);
Debug.Assert(nextFilter != null);
if (predicate == PredicateMiddleware <TContext, TEntity> .NullPredicate)
{
return nextFilter;
}
var predicateFunc = new Func <TEntity, bool>(predicate);
return source => nextFilter(source.Where(predicateFunc));
});
}
/// <summary>
/// Returns <c>true</c> if the given target matches the specified filter.
/// </summary>
/// <typeparam name="TSource"></typeparam>
/// <param name="target"></param>
/// <param name="filter"></param>
/// <returns></returns>
public static bool Matches <TSource>(TSource target, JObject filter)
{
return(filter != null?PredicateFunc <TSource>(filter)(target) : true);
}
public SpyPredicateCreator(PredicateFunc <DummyEntity> predicate) => _predicate = predicate;