private void BuildProjector(LambdaExpression projectionLambda, LambdaExpression aggregator, out Delegate projector, out Delegate asyncProjector)
{
var sqlQueryProviderParam = Expression.Parameter(typeof(SqlQueryProvider));
var formatResultsParam = Expression.Parameter(typeof(SqlQueryFormatResult));
var placeholderValuesParam = Expression.Parameter(typeof(object[]));
var elementType = projectionLambda.ReturnType;
Expression executor;
if (elementType.IsDataAccessObjectType())
{
var concreteElementType = this.DataAccessModel.GetConcreteTypeFromDefinitionType(elementType);
var constructor = typeof(DataAccessObjectProjector <,>).MakeGenericType(elementType, concreteElementType).GetConstructors(BindingFlags.Public | BindingFlags.Instance).Single();
executor = Expression.New
(
constructor,
sqlQueryProviderParam,
Expression.Constant(this.DataAccessModel),
Expression.Constant(this.SqlDatabaseContext),
formatResultsParam,
placeholderValuesParam,
projectionLambda
);
}
else
{
if ((aggregator?.Body as MethodCallExpression)?.Method.GetGenericMethodOrRegular() == MethodInfoFastRef.EnumerableExtensionsAlwaysReadFirstMethod)
{
var constructor = typeof(AlwaysReadFirstObjectProjector <,>).MakeGenericType(projectionLambda.ReturnType, projectionLambda.ReturnType).GetConstructors(BindingFlags.Public | BindingFlags.Instance).Single();
executor = Expression.New
(
constructor,
sqlQueryProviderParam,
Expression.Constant(this.DataAccessModel),
Expression.Constant(this.SqlDatabaseContext),
formatResultsParam,
placeholderValuesParam,
projectionLambda
);
}
else
{
var projectorType = !DataAccessObjectAwareResultTypeComparerBuilder.NeedsComparer(projectionLambda.ReturnType) ? typeof(ObjectProjector <,>) : typeof(DataAccessObjectContainerProjector <,>);
var constructor = projectorType.MakeGenericType(projectionLambda.ReturnType, projectionLambda.ReturnType).GetConstructors(BindingFlags.Public | BindingFlags.Instance).Single();
executor = Expression.New
(
constructor,
sqlQueryProviderParam,
Expression.Constant(this.DataAccessModel),
Expression.Constant(this.SqlDatabaseContext),
formatResultsParam,
placeholderValuesParam,
projectionLambda
);
}
}
var asyncExecutor = executor;
var cancellationToken = Expression.Parameter(typeof(CancellationToken));
if (aggregator != null)
{
var originalExecutor = executor;
var aggr = aggregator;
var newBody = SqlConstantPlaceholderReplacer.Replace(aggr.Body, placeholderValuesParam);
executor = SqlExpressionReplacer.Replace(newBody, aggr.Parameters[0], originalExecutor);
newBody = ProjectionAsyncRewriter.Rewrite(newBody, cancellationToken);
asyncExecutor = SqlExpressionReplacer.Replace(newBody, aggr.Parameters[0], originalExecutor);
}
projectionLambda = Expression.Lambda(executor, sqlQueryProviderParam, formatResultsParam, placeholderValuesParam);
var asyncProjectorLambda = Expression.Lambda(asyncExecutor, sqlQueryProviderParam, formatResultsParam, placeholderValuesParam, cancellationToken);
ProjectorCacheInfo cacheInfo;
var key = new ProjectorCacheKey(projectionLambda);
var oldCache = this.SqlDatabaseContext.projectorCache;
if (!oldCache.TryGetValue(key, out cacheInfo))
{
cacheInfo.projector = projectionLambda.Compile();
cacheInfo.asyncProjector = asyncProjectorLambda.Compile();
if (this.SqlDatabaseContext.projectorCache.Count >= ProjectorCacheMaxLimit)
{
ProjectionExpressionCacheLogger.Info(() => $"Projector has been flushed because it overflowed with a size of {ProjectionExpressionCacheMaxLimit}\n\nProjector: {projectionLambda}\n\nAt: {new StackTrace()}");
var newCache = new Dictionary <ProjectorCacheKey, ProjectorCacheInfo>(ProjectorCacheMaxLimit, ProjectorCacheEqualityComparer.Default);
foreach (var value in oldCache.Take(oldCache.Count / 3))
{
newCache[value.Key] = value.Value;
}
newCache[key] = cacheInfo;
this.SqlDatabaseContext.projectorCache = newCache;
}
else
{
var newCache = new Dictionary <ProjectorCacheKey, ProjectorCacheInfo>(oldCache, ProjectorCacheEqualityComparer.Default)
{
[key] = cacheInfo
};
this.SqlDatabaseContext.projectorCache = newCache;
}
ProjectionCacheLogger.Info(() => $"Cached projector:\n{cacheInfo.projector}");
ProjectionCacheLogger.Debug(() => $"Projector Cache Size: {this.SqlDatabaseContext.projectionExpressionCache.Count}");
}
projector = cacheInfo.projector;
asyncProjector = cacheInfo.asyncProjector;
}
public DataAccessObjectContainerProjector(SqlQueryProvider provider, DataAccessModel dataAccessModel, SqlDatabaseContext sqlDatabaseContext, SqlQueryFormatResult formatResult, object[] placeholderValues, Func <ObjectProjector, IDataReader, int, object[], Func <DataAccessObject, DataAccessObject>, U> objectReader)
: base(provider, dataAccessModel, sqlDatabaseContext, formatResult, placeholderValues, objectReader)
{
outputComparer = DataAccessObjectAwareResultTypeComparerBuilder.CreateComparer <T>();
}
