public ConstructedValueExpression Compile(MapTypeContext context)
{
if (!context.TargetType.IsSupportedPrimitiveType() && context.TargetType != typeof(object))
{
return(ConstructedValueExpression.Nothing);
}
var column = context.SingleColumn();
if (column == null)
{
return(ConstructedValueExpression.Nothing);
}
// Pull the value out of the reader into the rawVar
var rawVar = context.CreateVariable(typeof(object), "raw");
var getRawStmt = Expression.Assign(
rawVar,
Expression.Call(
context.RecordParameter,
_getValueMethod,
Expression.Constant(column.Index)
)
);
var rawConvertExpr = MapScalar(context.TargetType, column, rawVar);
column.MarkMapped();
return(new ConstructedValueExpression(new[] { getRawStmt }, rawConvertExpr, new[] { rawVar }));
}
private ConstructedValueExpression CompileArrayOfScalar(MapTypeContext context, ConstructorInfo constructor, List <ColumnInfo> columns, Type elementType)
{
var arrayVar = context.CreateVariable(context.TargetType, "array");
var expressions = new List <Expression>();
var variables = new List <ParameterExpression>();
variables.Add(arrayVar);
expressions.Add(
Expression.Assign(
arrayVar,
Expression.New(
constructor,
Expression.Constant(columns.Count)
)
)
);
for (int i = 0; i < columns.Count; i++)
{
var columnState = context.GetSubstateForColumn(columns[i], elementType, null);
var getScalarExpression = _scalars.Compile(columnState);
expressions.AddRange(getScalarExpression.Expressions);
expressions.Add(
Expression.Assign(
Expression.ArrayAccess(
arrayVar,
Expression.Constant(i)
),
getScalarExpression.FinalValue
)
);
variables.AddRange(getScalarExpression.Variables);
}
return(new ConstructedValueExpression(expressions, arrayVar, variables));
}
public static ConstructedValueExpression GetMaybeInstantiateDictionaryExpression(MapTypeContext context, ConstructorInfo constructor)
{
var newInstance = context.CreateVariable(context.TargetType, "dictionary");
if (context.GetExisting == null)
{
// There's no way to get an existing value, so call the parameterless constructor
var getNewInstanceExpr = Expression.Assign(
newInstance,
Expression.New(constructor)
);
return(new ConstructedValueExpression(new[] { getNewInstanceExpr }, newInstance, new[] { newInstance }));
}
// Try to get the existing value. If we have it return it. Otherwise call the default
// parameterless constructor
var tryGetExistingInstanceExpr = Expression.Assign(
newInstance,
Expression.Condition(
Expression.Equal(
context.GetExisting,
Expression.Constant(null)
),
Expression.Convert(
Expression.New(constructor),
context.TargetType
),
Expression.Convert(context.GetExisting, context.TargetType)
)
);
return(new ConstructedValueExpression(new[] { tryGetExistingInstanceExpr }, newInstance, new[] { newInstance }));
}
public static ConstructedValueExpression GetMaybeInstantiateCollectionExpression(MapTypeContext context, ConstructorInfo constructor)
{
var newInstance = context.CreateVariable(context.TargetType, "list");
if (context.GetExisting == null)
{
// if we don't have an expression to get an existing slot, just create new by
// calling the default parameterless constructor on the collection type
var createNewExpr = Expression.Assign(
newInstance,
Expression.New(constructor)
);
return(new ConstructedValueExpression(new[] { createNewExpr }, newInstance, new[] { newInstance }));
}
// Try to get the existing value. If it's null, just create new with the default
// parameterless constructor. If it's not null we can return it.
var getExistingExpr = Expression.Assign(
newInstance,
Expression.Condition(
Expression.Equal(
context.GetExisting,
Expression.Constant(null)
),
Expression.Convert(
Expression.New(constructor),
context.TargetType
),
Expression.Convert(context.GetExisting, context.TargetType)
)
);
return(new ConstructedValueExpression(new[] { getExistingExpr }, newInstance, new[] { newInstance }));
}
private ConstructedValueExpression AddInstantiationExpressionForObjectInstance(MapTypeContext context)
{
var instanceVar = context.CreateVariable(context.TargetType, "instance");
var typeInfo = context.Settings.GetTypeSettings(context.TargetType);
var defaultSubtypeInfo = typeInfo.GetDefault();
var defaultInstantiationExpression = AddInstantiationExpressionForSpecificType(context, defaultSubtypeInfo, instanceVar);
var subclasses = typeInfo.GetSpecificTypes().ToList();
// If we have no configured subclass predicates, instantiate the target type directly
if (subclasses.Count == 0)
{
return(new ConstructedValueExpression(defaultInstantiationExpression.Expressions, instanceVar, defaultInstantiationExpression.Variables.Concat(new[] { instanceVar })));
}
// If we have configured subclass predicates, unroll the loop and write expressions for
// all cases. The default case will be executed if no subclass predicates match.
var endLabel = context.CreateLabel("haveinstance");
var expressions = new List <Expression>();
foreach (var subclass in subclasses.Where(s => s.Predicate != null))
{
var instantiateExpressions = AddInstantiationExpressionForSpecificType(context, subclass, instanceVar);
// Check the subclass predicate. If it matches, we enter into a block where we
// create the subclass instance and then jump to the end label. Otherwise we
// fall through to the next subclass.
expressions.Add(
Expression.IfThen(
Expression.Call(
Expression.Constant(subclass.Predicate.Target),
subclass.Predicate.Method,
context.RecordParameter
),
Expression.Block(
instantiateExpressions.Variables,
instantiateExpressions.Expressions.Concat(new[] {
Expression.Goto(endLabel.Target)
})
)
)
);
}
// A block where we fall back to the default instantiation rules for the type, and then
// fall through to the endLabel. The block here allows us to scope variables a little
// more tightly
expressions.Add(
Expression.Block(
defaultInstantiationExpression.Variables,
defaultInstantiationExpression.Expressions
)
);
expressions.Add(endLabel);
return(new ConstructedValueExpression(expressions, instanceVar, new[] { instanceVar }));
}
private ConstructedValueExpression CompileArrayOfCustomObject(MapTypeContext context, Type elementType, ConstructorInfo constructor)
{
var expressions = new List <Expression>();
var variables = new List <ParameterExpression>();
// We don't loop here because we need to know how many items we have in the array and we
// can't calculate that because the custom object might consume any number of columns. We don't
// know until after each iteration has returned how many columns are left. We could map to
// a List and then .ToArray() to get the array, but that seems wasteful.
var arrayVar = context.CreateVariable(context.TargetType, "array");
variables.Add(arrayVar);
var elementState = context.ChangeTargetType(elementType);
var result = _customObjects.Compile(elementState);
expressions.AddRange(result.Expressions);
// Create a new array with a length of 1
expressions.Add(
Expression.Assign(
arrayVar,
Expression.New(
constructor,
Expression.Constant(1)
)
)
);
// Set the value to the first slot in the array
expressions.Add(
Expression.Assign(
Expression.ArrayAccess(
arrayVar,
Expression.Constant(0)
),
result.FinalValue
)
);
variables.AddRange(result.Variables);
return(new ConstructedValueExpression(expressions, arrayVar, variables));
}