protected override Expression VisitMemberAccess(MemberExpression m)
{
base.VisitMemberAccess(m);
ModelStep step;
if (m.Expression != null && steps.TryGetValue(m.Expression, out step) && !(step.Property is ModelValueProperty))
{
// Get the model type of the parent expression
var type = step.Property == null ? path.RootType : ((ModelReferenceProperty)step.Property).PropertyType;
// Determine if the member access represents a property on the model type
var property = type.Properties[m.Member.Name];
// If the property exists on the model type, create and record a new step
if (property != null)
{
var nextStep = step.NextSteps.FirstOrDefault(s => s.Property == property);
if (nextStep == null)
{
nextStep = new ModelStep(path)
{
Property = property, PreviousStep = step
};
step.NextSteps.Add(nextStep);
}
steps.Add(m, nextStep);
}
}
return(m);
}
protected override Expression VisitModelParameter(ModelExpression.ModelParameterExpression p)
{
// Add the root step
if (rootStep == null)
{
rootStep = new ModelStep(path);
steps.Add(p, rootStep);
}
return(p);
}
/// <summary>
/// Safely removes an invalid step from a path.
/// </summary>
/// <param name="step"></param>
static void RemoveStep(ModelStep step)
{
// Remove steps that do not lead to the end of the path
if (step.Property != null && !step.NextSteps.Any())
{
var previousStep = step;
while (previousStep != null && !previousStep.NextSteps.Any())
{
previousStep.NextSteps.Remove(previousStep);
previousStep = previousStep.PreviousStep;
}
}
}
protected override Expression VisitModelMember(ModelExpression.ModelMemberExpression m)
{
base.VisitModelMember(m);
ModelStep step;
if (steps.TryGetValue(m.Expression, out step) && !(step.Property is ModelValueProperty))
{
// Get the model type of the parent expression
var type = step.Property == null ? path.RootType : ((ModelReferenceProperty)step.Property).PropertyType;
// Make sure the type of the expression matches the declaring type of the property
if (type != m.Property.DeclaringType && !m.Property.DeclaringType.IsSubType(type))
{
return(m);
}
// Determine if the member access represents a property on the model type
var property = m.Property;
// Create and record a new step
var nextStep = step.NextSteps.FirstOrDefault(s => s.Property == property);
if (nextStep == null)
{
nextStep = new ModelStep(path)
{
Property = property, PreviousStep = step
};
step.NextSteps.Add(nextStep);
}
if (!steps.ContainsKey(m))
{
steps.Add(m, nextStep);
}
}
return(m);
}
/// <summary>
/// Creates a new <see cref="ModelPath"/> instance for the specified root <see cref="ModelType"/>
/// and path string.
/// </summary>
/// <param name="rootType"></param>
/// <param name="path"></param>
internal static ModelPath CreatePath(ModelType rootType, string path)
{
// Create the new path
ModelPath newPath = new ModelPath()
{
RootType = rootType
};
// Create a temporary root step
var root = new ModelStep(newPath);
var steps = new List <ModelStep>()
{
root
};
var stack = new Stack <List <ModelStep> >();
int expectedTokenStart = 0;
var tokenMatches = pathParser.Matches(path);
int tokenIndex = 0;
foreach (Match tokenMatch in tokenMatches)
{
// ensure there are no gaps between tokens except for whitespace
if (tokenMatch.Index != expectedTokenStart && path.Substring(expectedTokenStart, tokenMatch.Index - expectedTokenStart - 1).Trim() != "")
{
return(null); // throw new ArgumentException("The specified path, '" + path + "', is not valid. Character " + (expectedTokenStart));
}
expectedTokenStart = tokenMatch.Index + tokenMatch.Length;
var token = tokenMatch.Value;
switch (token[0])
{
case '{':
stack.Push(steps);
break;
case '}':
steps = stack.Pop();
break;
case ',':
steps = stack.Peek();
break;
case '.':
break;
case '<':
var filter = rootType.Context.GetModelType(token.Substring(1, token.Length - 2));
foreach (var step in steps)
{
if (step.Property is ModelReferenceProperty &&
(((ModelReferenceProperty)step.Property).PropertyType == filter ||
((ModelReferenceProperty)step.Property).PropertyType.IsSubType(filter)))
{
step.Filter = filter;
}
else
{
RemoveStep(step);
}
}
break;
default:
// Get the property name for the next step
var propertyName = token;
// Track the next steps
var nextSteps = new List <ModelStep>();
// Process each of the current steps
foreach (var step in steps)
{
// Ensure the current step is a valid reference property
if (step.Property != null && step.Property is ModelValueProperty)
{
return(null); // throw new ArgumentException("Property '" + step.Property.Name + "' is a value property and cannot have child properties specified.");
}
// Get the type of the current step
var currentType = step.Property != null ? ((ModelReferenceProperty)step.Property).PropertyType : step.Path.RootType;
if (step.Filter != null)
{
if (step.Filter != currentType && !currentType.IsSubType(step.Filter))
{
return(null); // throw new ArgumentException("Filter type '" + step.Filter.Name + "' is not a valid subtype of '" + currentType.Name + "'.");
}
currentType = step.Filter;
}
// Process the current and all subtypes, honoring any specified type filters
foreach (var type in currentType.GetDescendentsInclusive())
{
// Get the current property
var property = type.Properties[propertyName];
// Ensure the property is valid
if (property == null || property.IsStatic || (property.DeclaringType != type && type != currentType && currentType.Properties[propertyName] != null))
{
continue;
}
// Look ahead to see if this step is filtered
filter = tokenIndex < tokenMatches.Count - 1 && tokenMatches[tokenIndex + 1].Value.StartsWith("<") ?
rootType.Context.GetModelType(tokenMatches[tokenIndex + 1].Value.Substring(1, tokenMatches[tokenIndex + 1].Length - 2)) :
null;
// See if the step already exists for this property and filter or needs to be created
var nextStep = step.NextSteps.Where(s => s.Property == property && s.Filter == filter).FirstOrDefault();
if (nextStep == null)
{
nextStep = new ModelStep(newPath)
{
Property = property, Filter = filter, PreviousStep = step.Property != null ? step : null
};
step.NextSteps.Add(nextStep);
}
nextSteps.Add(nextStep);
}
// Remove steps that do not lead to the end of the path
RemoveStep(step);
}
// Immediately exit if no steps were found matching the requested path
if (nextSteps.Count == 0)
{
return(null);
}
steps = nextSteps;
break;
}
++tokenIndex;
}
// Throw an exception if there are unmatched property group delimiters
if (stack.Count > 0)
{
throw new ArgumentException("Unclosed '{' in path: " + path, "path");
}
// Return null if the path was not valid
if (!root.NextSteps.Any())
{
return(null);
}
// Otherwise, finish initializing and return the new path
newPath.FirstSteps = root.NextSteps;
newPath.Path = path;
return(newPath);
}
protected override Expression VisitParameter(ParameterExpression p)
{
base.VisitParameter(p);
// Add the root step
if (rootStep == null)
{
rootStep = new ModelStep(path);
steps.Add(p, rootStep);
}
return p;
}
protected override Expression VisitModelMember(ModelExpression.ModelMemberExpression m)
{
base.VisitModelMember(m);
ModelStep step;
if (steps.TryGetValue(m.Expression, out step) && !(step.Property is ModelValueProperty))
{
// Get the model type of the parent expression
var type = step.Property == null ? path.RootType : ((ModelReferenceProperty)step.Property).PropertyType;
// Make sure the type of the expression matches the declaring type of the property
if (type != m.Property.DeclaringType && !m.Property.DeclaringType.IsSubType(type))
return m;
// Determine if the member access represents a property on the model type
var property = m.Property;
// Create and record a new step
var nextStep = step.NextSteps.FirstOrDefault(s => s.Property == property);
if (nextStep == null)
{
nextStep = new ModelStep(path) { Property = property, PreviousStep = step };
step.NextSteps.Add(nextStep);
}
if (!steps.ContainsKey(m))
steps.Add(m, nextStep);
}
return m;
}
protected override Expression VisitMemberAccess(MemberExpression m)
{
base.VisitMemberAccess(m);
ModelStep step;
if (m.Expression != null && steps.TryGetValue(m.Expression, out step) && !(step.Property is ModelValueProperty))
{
// Get the model type of the parent expression
var type = step.Property == null ? path.RootType : ((ModelReferenceProperty)step.Property).PropertyType;
// Determine if the member access represents a property on the model type
var property = type.Properties[m.Member.Name];
// If the property exists on the model type, create and record a new step
if (property != null)
{
var nextStep = step.NextSteps.FirstOrDefault(s => s.Property == property);
if (nextStep == null)
{
nextStep = new ModelStep(path) { Property = property, PreviousStep = step };
step.NextSteps.Add(nextStep);
}
steps.Add(m, nextStep);
}
}
return m;
}
/// <summary>
/// Safely removes an invalid step from a path.
/// </summary>
/// <param name="step"></param>
static void RemoveStep(ModelStep step)
{
// Remove steps that do not lead to the end of the path
if (step.Property != null && !step.NextSteps.Any())
{
var previousStep = step;
while (previousStep != null && !previousStep.NextSteps.Any())
{
previousStep.NextSteps.Remove(previousStep);
previousStep = previousStep.PreviousStep;
}
}
}
/// <summary>
/// Creates a new <see cref="ModelPath"/> instance for the specified root <see cref="ModelType"/>
/// and path string.
/// </summary>
/// <param name="rootType"></param>
/// <param name="path"></param>
internal static ModelPath CreatePath(ModelType rootType, string path)
{
// Create the new path
ModelPath newPath = new ModelPath()
{
RootType = rootType
};
// Create a temporary root step
var root = new ModelStep(newPath);
var steps = new List<ModelStep>() { root };
var stack = new Stack<List<ModelStep>>();
int expectedTokenStart = 0;
var tokenMatches = pathParser.Matches(path);
int tokenIndex = 0;
foreach (Match tokenMatch in tokenMatches)
{
// ensure there are no gaps between tokens except for whitespace
if (tokenMatch.Index != expectedTokenStart && path.Substring(expectedTokenStart, tokenMatch.Index - expectedTokenStart - 1).Trim() != "" )
return null; // throw new ArgumentException("The specified path, '" + path + "', is not valid. Character " + (expectedTokenStart));
expectedTokenStart = tokenMatch.Index + tokenMatch.Length;
var token = tokenMatch.Value;
switch (token[0])
{
case '{':
stack.Push(steps);
break;
case '}':
steps = stack.Pop();
break;
case ',':
steps = stack.Peek();
break;
case '.':
break;
case '<':
var filter = rootType.Context.GetModelType(token.Substring(1, token.Length - 2));
foreach (var step in steps)
{
if (step.Property is ModelReferenceProperty &&
(((ModelReferenceProperty)step.Property).PropertyType == filter ||
((ModelReferenceProperty)step.Property).PropertyType.IsSubType(filter)))
step.Filter = filter;
else
RemoveStep(step);
}
break;
default:
// Get the property name for the next step
var propertyName = token;
// Track the next steps
var nextSteps = new List<ModelStep>();
// Process each of the current steps
foreach (var step in steps)
{
// Ensure the current step is a valid reference property
if (step.Property != null && step.Property is ModelValueProperty)
return null; // throw new ArgumentException("Property '" + step.Property.Name + "' is a value property and cannot have child properties specified.");
// Get the type of the current step
var currentType = step.Property != null ? ((ModelReferenceProperty)step.Property).PropertyType : step.Path.RootType;
if (step.Filter != null)
{
if (step.Filter != currentType && !currentType.IsSubType(step.Filter))
return null; // throw new ArgumentException("Filter type '" + step.Filter.Name + "' is not a valid subtype of '" + currentType.Name + "'.");
currentType = step.Filter;
}
// Process the current and all subtypes, honoring any specified type filters
foreach (var type in currentType.GetDescendentsInclusive())
{
// Get the current property
var property = type.Properties[propertyName];
// Ensure the property is valid
if (property == null || property.IsStatic || (property.DeclaringType != type && type != currentType && currentType.Properties[propertyName] != null))
continue;
// Look ahead to see if this step is filtered
filter = tokenIndex < tokenMatches.Count - 1 && tokenMatches[tokenIndex + 1].Value.StartsWith("<") ?
rootType.Context.GetModelType(tokenMatches[tokenIndex + 1].Value.Substring(1, tokenMatches[tokenIndex + 1].Length - 2)) :
null;
// See if the step already exists for this property and filter or needs to be created
var nextStep = step.NextSteps.Where(s => s.Property == property && s.Filter == filter).FirstOrDefault();
if (nextStep == null)
{
nextStep = new ModelStep(newPath) { Property = property, Filter = filter, PreviousStep = step.Property != null ? step : null };
step.NextSteps.Add(nextStep);
}
nextSteps.Add(nextStep);
}
// Remove steps that do not lead to the end of the path
RemoveStep(step);
}
// Immediately exit if no steps were found matching the requested path
if (nextSteps.Count == 0)
return null;
steps = nextSteps;
break;
}
++tokenIndex;
}
// Throw an exception if there are unmatched property group delimiters
if (stack.Count > 0)
throw new ArgumentException("Unclosed '{' in path: " + path, "path");
// Return null if the path was not valid
if (!root.NextSteps.Any())
return null;
// Otherwise, finish initializing and return the new path
newPath.FirstSteps = root.NextSteps;
newPath.Path = path;
return newPath;
}
