// public static methods
public static ExecutableQuery <TDocument, TOutput> Translate <TDocument>(MongoQueryProvider <TDocument> provider, TranslationContext context, MethodCallExpression expression)
{
var method = expression.Method;
var arguments = expression.Arguments;
if (method.IsOneOf(__averageMethods))
{
var sourceExpression = arguments[0];
var pipeline = ExpressionToPipelineTranslator.Translate(context, sourceExpression);
var sourceSerializer = pipeline.OutputSerializer;
AstExpression valueExpression;
if (method.IsOneOf(__averageWithSelectorMethods))
{
var selectorLambda = ExpressionHelper.UnquoteLambda(arguments[1]);
var selectorTranslation = ExpressionToAggregationExpressionTranslator.TranslateLambdaBody(context, selectorLambda, sourceSerializer, asRoot: true);
valueExpression = selectorTranslation.Ast;
}
else
{
Ensure.That(sourceSerializer is IWrappedValueSerializer, "Expected sourceSerializer to be an IWrappedValueSerializer.", nameof(sourceSerializer));
var root = AstExpression.Var("ROOT", isCurrent: true);
valueExpression = AstExpression.GetField(root, "_v");
}
IBsonSerializer outputValueSerializer = expression.GetResultType() switch
{
Type t when t == typeof(int) => new Int32Serializer(),
Type t when t == typeof(long) => new Int64Serializer(),
Type t when t == typeof(float) => new SingleSerializer(),
Type t when t == typeof(double) => new DoubleSerializer(),
Type t when t == typeof(decimal) => new DecimalSerializer(),
Type {
IsConstructedGenericType : true
} t when t.GetGenericTypeDefinition() == typeof(Nullable <>) => (IBsonSerializer)Activator.CreateInstance(typeof(NullableSerializer <>).MakeGenericType(t.GenericTypeArguments[0])),
_ => throw new ExpressionNotSupportedException(expression)
};
var outputWrappedValueSerializer = WrappedValueSerializer.Create("_v", outputValueSerializer);
pipeline = pipeline.AddStages(
outputWrappedValueSerializer,
AstStage.Group(
id: BsonNull.Value,
fields: AstExpression.AccumulatorField("_v", AstAccumulatorOperator.Avg, valueExpression)),
AstStage.Project(AstProject.ExcludeId()));
return(ExecutableQuery.Create(
provider.Collection,
provider.Options,
pipeline,
__finalizer));
}
throw new ExpressionNotSupportedException(expression);
}
}
// public static methods
public static ExecutableQuery <TDocument, TOutput> Translate <TDocument>(MongoQueryProvider <TDocument> provider, TranslationContext context, MethodCallExpression expression)
{
var method = expression.Method;
var arguments = expression.Arguments;
if (method.IsOneOf(__standardDeviationMethods))
{
var sourceExpression = ConvertHelper.RemoveConvertToMongoQueryable(arguments[0]);
var pipeline = ExpressionToPipelineTranslator.Translate(context, sourceExpression);
var sourceSerializer = pipeline.OutputSerializer;
var stdDevOperator = method.IsOneOf(__standardDeviationPopulationMethods) ? AstAccumulatorOperator.StdDevPop : AstAccumulatorOperator.StdDevSamp;
AstExpression valueAst;
if (method.IsOneOf(__standardDeviationWithSelectorMethods))
{
var selectorLambda = ExpressionHelper.UnquoteLambda(arguments[1]);
var selectorTranslation = ExpressionToAggregationExpressionTranslator.TranslateLambdaBody(context, selectorLambda, sourceSerializer, asRoot: true);
valueAst = selectorTranslation.Ast;
}
else
{
var root = AstExpression.Var("ROOT", isCurrent: true);
valueAst = AstExpression.GetField(root, "_v");
}
var outputValueType = expression.GetResultType();
var outputValueSerializer = BsonSerializer.LookupSerializer(outputValueType);
var outputWrappedValueSerializer = WrappedValueSerializer.Create("_v", outputValueSerializer);
pipeline = pipeline.AddStages(
outputWrappedValueSerializer,
AstStage.Group(
id: BsonNull.Value,
AstExpression.AccumulatorField("_v", stdDevOperator, valueAst)),
AstStage.Project(AstProject.ExcludeId()));
var finalizer = method.IsOneOf(__standardDeviationNullableMethods) ? __singleOrDefaultFinalizer : __singleFinalizer;
return(ExecutableQuery.Create(
provider.Collection,
provider.Options,
pipeline,
finalizer));
}
throw new ExpressionNotSupportedException(expression);
}
// public static methods
public static ExecutableQuery <TDocument, TOutput> Translate <TDocument>(MongoQueryProvider <TDocument> provider, TranslationContext context, MethodCallExpression expression)
{
var method = expression.Method;
var arguments = expression.Arguments;
if (method.IsOneOf(__sumMethods))
{
var sourceExpression = arguments[0];
var pipeline = ExpressionToPipelineTranslator.Translate(context, sourceExpression);
var sourceSerializer = pipeline.OutputSerializer;
AstExpression valueAst;
if (method.IsOneOf(__sumWithSelectorMethods))
{
var selectorLambda = ExpressionHelper.UnquoteLambda(arguments[1]);
var selectorTranslation = ExpressionToAggregationExpressionTranslator.TranslateLambdaBody(context, selectorLambda, sourceSerializer, asRoot: true);
valueAst = selectorTranslation.Ast;
}
else
{
Ensure.That(sourceSerializer is IWrappedValueSerializer, "Expected sourceSerializer to be an IWrappedValueSerializer.", nameof(sourceSerializer));
var rootVar = AstExpression.Var("ROOT", isCurrent: true);
valueAst = AstExpression.GetField(rootVar, "_v");
}
var outputValueType = expression.GetResultType();
var outputValueSerializer = BsonSerializer.LookupSerializer(outputValueType);
var outputWrappedValueSerializer = WrappedValueSerializer.Create("_v", outputValueSerializer);
pipeline = pipeline.AddStages(
outputWrappedValueSerializer,
AstStage.Group(
id: BsonNull.Value,
fields: AstExpression.AccumulatorField("_v", AstAccumulatorOperator.Sum, valueAst)),
AstStage.Project(AstProject.ExcludeId()));
return(ExecutableQuery.Create(
provider.Collection,
provider.Options,
pipeline,
__finalizer));
}
throw new ExpressionNotSupportedException(expression);
}