Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataWeb / Client / System / Data / Services / Client / ProjectionPlanCompiler.cs / 1305376 / ProjectionPlanCompiler.cs
//----------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//
// Provides a class that can create a materialization plan for a
// projection.
//
//---------------------------------------------------------------------
//// Uncomment the following line to trace projection building activity.
////#define TRACE_CLIENT_PROJECTIONS
namespace System.Data.Services.Client
{
#region Namespaces.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
#endregion Namespaces.
///
/// Use this class to create a for a given projection lambda.
///
internal class ProjectionPlanCompiler : ALinqExpressionVisitor
{
#region Private fields.
/// Annotations being tracked on this tree.
private readonly Dictionary annotations;
/// Expression that refers to the materializer.
private readonly ParameterExpression materializerExpression;
/// Tracks rewrite-to-source rewrites introduced by expression normalizer.
private readonly Dictionary normalizerRewrites;
/// Number to suffix to identifiers to help with debugging.
private int identifierId;
/// Path builder used to help with tracking state while compiling.
private ProjectionPathBuilder pathBuilder;
/// Whether the top level projection has been found.
private bool topLevelProjectionFound;
#endregion Private fields.
#region Constructors.
///
/// Initializes a new instance.
///
/// Rewrites introduces by normalizer.
private ProjectionPlanCompiler(Dictionary normalizerRewrites)
{
this.annotations = new Dictionary(ReferenceEqualityComparer.Instance);
this.materializerExpression = Expression.Parameter(typeof(object), "mat");
this.normalizerRewrites = normalizerRewrites;
this.pathBuilder = new ProjectionPathBuilder();
}
#endregion Constructors.
#region Internal methods.
/// Creates a projection plan from the specified .
/// Projection expression.
/// Tracks rewrite-to-source rewrites introduced by expression normalizer.
/// A new instance.
internal static ProjectionPlan CompilePlan(LambdaExpression projection, Dictionary normalizerRewrites)
{
Debug.Assert(projection != null, "projection != null");
Debug.Assert(projection.Parameters.Count == 1, "projection.Parameters.Count == 1");
Debug.Assert(
projection.Body.NodeType == ExpressionType.Constant ||
projection.Body.NodeType == ExpressionType.MemberInit ||
projection.Body.NodeType == ExpressionType.MemberAccess ||
projection.Body.NodeType == ExpressionType.Convert ||
projection.Body.NodeType == ExpressionType.ConvertChecked ||
projection.Body.NodeType == ExpressionType.New,
"projection.Body.NodeType == Constant, MemberInit, MemberAccess, Convert(Checked) New");
ProjectionPlanCompiler rewriter = new ProjectionPlanCompiler(normalizerRewrites);
#if TRACE_CLIENT_PROJECTIONS
Trace.WriteLine("Projection: " + projection);
#endif
Expression plan = rewriter.Visit(projection);
#if TRACE_CLIENT_PROJECTIONS
Trace.WriteLine("Becomes: " + plan);
#endif
ProjectionPlan result = new ProjectionPlan();
result.Plan = (Func)((LambdaExpression)plan).Compile();
result.ProjectedType = projection.Body.Type;
#if DEBUG
result.SourceProjection = projection;
result.TargetProjection = plan;
#endif
return result;
}
/// Binary visit method.
/// Binary expression to visit.
/// (Possibly rewritten) binary expression.
///
/// This override is introduced because binary expressions are one of
/// the scopes at which normalization happens.
///
internal override Expression VisitBinary(BinaryExpression b)
{
Expression original = this.GetExpressionBeforeNormalization(b);
if (original == b)
{
return base.VisitBinary(b);
}
else
{
return this.Visit(original);
}
}
/// Visits the specified expression.
/// Expression to check.
/// The visited expression.
///
/// This override allows us to check for rewrites created by
/// ExpressionNormalizer.CreateCompareExpression.
///
internal override Expression VisitConditional(ConditionalExpression conditional)
{
Debug.Assert(conditional != null, "conditional != null");
Expression original = this.GetExpressionBeforeNormalization(conditional);
if (original != conditional)
{
return this.Visit(original);
}
var nullCheck = ResourceBinder.PatternRules.MatchNullCheck(this.pathBuilder.LambdaParameterInScope, conditional);
if (!nullCheck.Match || !ClientType.CheckElementTypeIsEntity(nullCheck.AssignExpression.Type))
{
return base.VisitConditional(conditional);
}
return this.RebindConditionalNullCheck(conditional, nullCheck);
}
/// Unary visit method.
/// Unary expression to visit.
/// (Possibly rewritten) unary expression.
///
/// This override is introduced because unary expressions are one of
/// the scopes at which normalization happens.
///
internal override Expression VisitUnary(UnaryExpression u)
{
Expression original = this.GetExpressionBeforeNormalization(u);
Expression result;
if (original == u)
{
result = base.VisitUnary(u);
UnaryExpression unaryResult = result as UnaryExpression;
if (unaryResult != null)
{
ExpressionAnnotation annotation;
if (this.annotations.TryGetValue(unaryResult.Operand, out annotation))
{
this.annotations[result] = annotation;
}
}
}
else
{
result = this.Visit(original);
}
return result;
}
///
/// MemberExpression visit method
///
/// The MemberExpression expression to visit
/// The visited MemberExpression expression
internal override Expression VisitMemberAccess(MemberExpression m)
{
Debug.Assert(m != null, "m != null");
Expression result;
Expression baseSourceExpression = m.Expression;
// if primitive or nullable primitive, allow member access... i.e. calling Value on nullable
if (ClientConvert.IsKnownNullableType(baseSourceExpression.Type))
{
result = base.VisitMemberAccess(m);
}
else
{
Expression baseTargetExpression = this.Visit(baseSourceExpression);
ExpressionAnnotation annotation;
if (this.annotations.TryGetValue(baseTargetExpression, out annotation))
{
result = this.RebindMemberAccess(m, annotation);
}
else
{
result = Expression.MakeMemberAccess(baseTargetExpression, m.Member);
}
}
return result;
}
/// Parameter visit method.
/// Parameter to visit.
/// Resulting expression.
///
/// The parameter may get rewritten as a materializing projection if
/// it refers to an entity outside of member binding. In this case,
/// it becomes a standalone tracked entity.
///
internal override Expression VisitParameter(ParameterExpression p)
{
Debug.Assert(p != null, "p != null");
// If this parameter isn't interesting, we're not doing any rewrites.
Expression result;
ExpressionAnnotation annotation;
if (this.annotations.TryGetValue(p, out annotation))
{
result = this.RebindParameter(p, annotation);
}
else
{
result = base.VisitParameter(p);
}
return result;
}
///
/// MemberInitExpression visit method
///
/// The MemberInitExpression to visit
/// The visited MemberInitExpression
///
/// A MemberInitExpression on a knownEntityType implies that we
/// want to materialize the thing.
///
internal override Expression VisitMemberInit(MemberInitExpression init)
{
this.pathBuilder.EnterMemberInit(init);
Expression result = null;
if (this.pathBuilder.CurrentIsEntity && init.Bindings.Count > 0)
{
result = this.RebindEntityMemberInit(init);
}
else
{
result = base.VisitMemberInit(init);
}
this.pathBuilder.LeaveMemberInit();
return result;
}
/// Visits a method call expression.
/// Expression to visit.
/// A (possibly rewritten) expression for .
internal override Expression VisitMethodCall(MethodCallExpression m)
{
Debug.Assert(m != null, "m != null");
Expression original = this.GetExpressionBeforeNormalization(m);
if (original != m)
{
return this.Visit(original);
}
Expression result;
if (this.pathBuilder.CurrentIsEntity)
{
Debug.Assert(
ProjectionAnalyzer.IsMethodCallAllowedEntitySequence(m) || ResourceBinder.PatternRules.MatchReferenceEquals(m),
"ProjectionAnalyzer.IsMethodCallAllowedEntitySequence(m) || ResourceBinder.PatternRules.MatchReferenceEquals(m) -- otherwise ProjectionAnalyzer should have blocked this for entities");
if (m.Method.Name == "Select")
{
result = this.RebindMethodCallForMemberSelect(m);
}
else if (m.Method.Name == "ToList")
{
result = this.RebindMethodCallForMemberToList(m);
}
else
{
Debug.Assert(m.Method.Name == "ReferenceEquals", "We don't know how to handle this method, ProjectionAnalyzer updated?");
result = base.VisitMethodCall(m);
}
}
else
{
if (ProjectionAnalyzer.IsMethodCallAllowedEntitySequence(m))
{
result = this.RebindMethodCallForNewSequence(m);
}
else
{
result = base.VisitMethodCall(m);
}
}
return result;
}
/// Visits a new expression
/// Expression to visit
/// A (possibly rewritten) expression for .
internal override NewExpression VisitNew(NewExpression nex)
{
Debug.Assert(nex != null, "nex != null");
// Special case DataServiceCollection creation so context instance
// and paging (continuations) propperly flow through
if (ResourceBinder.PatternRules.MatchNewDataServiceCollectionOfT(nex))
{
return this.RebindNewExpressionForDataServiceCollectionOfT(nex);
}
return base.VisitNew(nex);
}
/// LambdaExpression visit method.
/// The LambdaExpression to visit
/// The visited LambdaExpression
internal override Expression VisitLambda(LambdaExpression lambda)
{
Debug.Assert(lambda != null, "lambda != null");
Expression result;
if (!this.topLevelProjectionFound || lambda.Parameters.Count == 1 && ClientType.CheckElementTypeIsEntity(lambda.Parameters[0].Type))
{
this.topLevelProjectionFound = true;
ParameterExpression expectedTypeParameter = Expression.Parameter(typeof(Type), "type" + this.identifierId);
ParameterExpression entryParameter = Expression.Parameter(typeof(object), "entry" + this.identifierId);
this.identifierId++;
this.pathBuilder.EnterLambdaScope(lambda, entryParameter, expectedTypeParameter);
ProjectionPath parameterPath = new ProjectionPath(lambda.Parameters[0], expectedTypeParameter, entryParameter);
ProjectionPathSegment parameterSegment = new ProjectionPathSegment(parameterPath, null, null);
parameterPath.Add(parameterSegment);
this.annotations[lambda.Parameters[0]] = new ExpressionAnnotation() { Segment = parameterSegment };
Expression body = this.Visit(lambda.Body);
// Value types must be boxed explicitly; the lambda initialization
// won't do it for us (type-compatible types still work, so all
// references will work fine with System.Object).
if (body.Type.IsValueType)
{
body = Expression.Convert(body, typeof(object));
}
result = Expression.Lambda>(
body,
this.materializerExpression,
entryParameter,
expectedTypeParameter);
this.pathBuilder.LeaveLambdaScope();
}
else
{
result = base.VisitLambda(lambda);
}
return result;
}
#endregion Internal methods.
#region Private methods.
/// Generates a call to a static method on AtomMaterializer.
/// Name of method to invoke.
/// Arguments to pass to method.
/// The constructed expression.
///
/// There is no support for overload resolution - method names in AtomMaterializer
/// must be unique.
///
private static Expression CallMaterializer(string methodName, params Expression[] arguments)
{
return CallMaterializerWithType(methodName, null, arguments);
}
/// Generates a call to a static method on AtomMaterializer.
/// Name of method to invoke.
/// Type arguments for method (possibly null).
/// Arguments to pass to method.
/// The constructed expression.
///
/// There is no support for overload resolution - method names in AtomMaterializer
/// must be unique.
///
private static Expression CallMaterializerWithType(string methodName, Type[] typeArguments, params Expression[] arguments)
{
Debug.Assert(methodName != null, "methodName != null");
Debug.Assert(arguments != null, "arguments != null");
MethodInfo method = typeof(AtomMaterializerInvoker).GetMethod(methodName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
Debug.Assert(method != null, "method != null - found " + methodName);
if (typeArguments != null)
{
method = method.MakeGenericMethod(typeArguments);
}
return Expression.Call(method, arguments);
}
/// Creates an expression that calls ProjectionCheckValueForPathIsNull.
/// Expression for root entry for paths.
/// Expression for expected type for entry.
/// Path to check null value for.
/// A new expression with the call instance.
private Expression CallCheckValueForPathIsNull(Expression entry, Expression entryType, ProjectionPath path)
{
Expression result = CallMaterializer("ProjectionCheckValueForPathIsNull", entry, entryType, Expression.Constant(path, typeof(object)));
this.annotations.Add(result, new ExpressionAnnotation() { Segment = path[path.Count - 1] });
return result;
}
/// Creates an expression that calls ProjectionValueForPath.
/// Expression for root entry for paths.
/// Expression for expected type for entry.
/// Path to pull value from.
/// A new expression with the call instance.
private Expression CallValueForPath(Expression entry, Expression entryType, ProjectionPath path)
{
Debug.Assert(entry != null, "entry != null");
Debug.Assert(path != null, "path != null");
Expression result = CallMaterializer("ProjectionValueForPath", this.materializerExpression, entry, entryType, Expression.Constant(path, typeof(object)));
this.annotations.Add(result, new ExpressionAnnotation() { Segment = path[path.Count - 1] });
return result;
}
/// Creates an expression that calls ProjectionValueForPath.
/// Expression for root entry for paths.
/// Expression for expected type for entry.
/// Path to pull value from.
/// Path to convert result for.
/// A new expression with the call instance.
private Expression CallValueForPathWithType(Expression entry, Expression entryType, ProjectionPath path, Type type)
{
Debug.Assert(entry != null, "entry != null");
Debug.Assert(path != null, "path != null");
Expression value = this.CallValueForPath(entry, entryType, path);
Expression result = Expression.Convert(value, type);
this.annotations.Add(result, new ExpressionAnnotation() { Segment = path[path.Count - 1] });
return result;
}
///
/// Rebinds a conditional that performs a null check on an entity.
///
/// Conditional expression.
/// Results of null check analysis.
/// The rebound expression.
///
/// Do a rewrite to avoid creating a type in the null check:
/// a.b == null ? null : [a.b]-based expression
/// becomes
/// ProjectionIsNull(a.b) ? null : [a.b]-based expression
///
private Expression RebindConditionalNullCheck(ConditionalExpression conditional, ResourceBinder.PatternRules.MatchNullCheckResult nullCheck)
{
Debug.Assert(conditional != null, "conditional != null");
Debug.Assert(nullCheck.Match, "nullCheck.Match -- otherwise no reason to call this rebind method");
Expression testToNullForProjection = this.Visit(nullCheck.TestToNullExpression);
Expression assignForProjection = this.Visit(nullCheck.AssignExpression);
ExpressionAnnotation testToNullAnnotation;
if (!this.annotations.TryGetValue(testToNullForProjection, out testToNullAnnotation))
{
return base.VisitConditional(conditional);
}
ProjectionPathSegment testToNullSegment = testToNullAnnotation.Segment;
Expression testToNullThroughMethod = this.CallCheckValueForPathIsNull(
testToNullSegment.StartPath.RootEntry,
testToNullSegment.StartPath.ExpectedRootType,
testToNullSegment.StartPath);
Expression test = testToNullThroughMethod;
Expression iftrue = Expression.Constant(null, assignForProjection.Type);
Expression iffalse = assignForProjection;
Expression result = Expression.Condition(test, iftrue, iffalse);
return result;
}
///
/// Rebinds the specified expression by gathering
/// annotated paths and returning an expression that calls the
/// ProjectionGetEntity method.
///
/// Member initialization expression.
/// A new expression suitable for materialization.
private Expression RebindEntityMemberInit(MemberInitExpression init)
{
Debug.Assert(init != null, "init != null");
Debug.Assert(init.Bindings.Count > 0, "init.Bindings.Count > 0 -- otherwise this is just empty construction");
// We "jump" into entities only if we're not already materializing an entity.
Expression[] expressions;
if (!this.pathBuilder.HasRewrites)
{
MemberAssignmentAnalysis propertyAnalysis = MemberAssignmentAnalysis.Analyze(
this.pathBuilder.LambdaParameterInScope,
((MemberAssignment)init.Bindings[0]).Expression);
expressions = propertyAnalysis.GetExpressionsToTargetEntity();
Debug.Assert(expressions.Length != 0, "expressions.Length != 0 -- otherwise there is no correlation to parameter in entity member init");
}
else
{
expressions = MemberAssignmentAnalysis.EmptyExpressionArray;
}
Expression entryParameterAtMemberInit = this.pathBuilder.ParameterEntryInScope;
List propertyNames = new List();
List> propertyFunctions = new List>();
Type projectedType = init.NewExpression.Type;
Expression projectedTypeExpression = Expression.Constant(projectedType, typeof(Type));
// We may need to materialize from deeper in the entity tree for anonymous types.
// t => new { nested = new Nested() { nid = t.nested.nid }
//
// We do the same kind of rewriting we'd do for a nested entity
// but at the initializing scope (rather than at the member assignment scope).
//
// t=> new { nested = ProjInit(GetEntry(entry0, "Nested"), "nid", *->nid) }
Expression entryToInitValue; // Expression that yields value for entry in target tree.
Expression expectedParamValue; // Expression that yield expectedType in target tree.
ParameterExpression entryParameterForMembers; // Parameter expression members think of as "entry".
ParameterExpression expectedParameterForMembers; // Parameter expression members think of as "expectedType" for entry.
string[] expressionNames = expressions.Skip(1).Select(e => ((MemberExpression)e).Member.Name).ToArray();
if (expressions.Length <= 1)
{
entryToInitValue = this.pathBuilder.ParameterEntryInScope;
expectedParamValue = this.pathBuilder.ExpectedParamTypeInScope;
entryParameterForMembers = (ParameterExpression)this.pathBuilder.ParameterEntryInScope;
expectedParameterForMembers = (ParameterExpression)this.pathBuilder.ExpectedParamTypeInScope;
}
else
{
entryToInitValue = this.GetDeepestEntry(expressions);
expectedParamValue = projectedTypeExpression;
entryParameterForMembers = Expression.Parameter(typeof(object), "subentry" + this.identifierId++);
expectedParameterForMembers = (ParameterExpression)this.pathBuilder.ExpectedParamTypeInScope;
// Annotate the entry expression with 'how we get to it' information.
// The annotation on entryToInitiValue is picked up
// The annotation on entryParameterForMembers is picked up to build nested member-init on entities.
ProjectionPath entryPath = new ProjectionPath(
(ParameterExpression)this.pathBuilder.LambdaParameterInScope,
this.pathBuilder.ExpectedParamTypeInScope,
this.pathBuilder.ParameterEntryInScope,
expressions.Skip(1));
this.annotations.Add(entryToInitValue, new ExpressionAnnotation() { Segment = entryPath[entryPath.Count - 1] });
this.annotations.Add(entryParameterForMembers, new ExpressionAnnotation() { Segment = entryPath[entryPath.Count - 1] });
this.pathBuilder.RegisterRewrite(this.pathBuilder.LambdaParameterInScope, expressionNames, entryParameterForMembers);
}
for (int i = 0; i < init.Bindings.Count; i++)
{
MemberAssignment assignment = (MemberAssignment)init.Bindings[i];
propertyNames.Add(assignment.Member.Name);
LambdaExpression propertyLambda;
// Here are the rewrites we do for member inits:
// new T { id = t.id }
// => ProjInit(pt, "id", f(t -> *.id));
//
// new T { t2 = new T2 { id2 = *.t2.id2 } }
// => ProjInit(pt, "t2", f(ProjInit(pt->t2), "id2", *.id2)))
if ((ClientType.CheckElementTypeIsEntity(assignment.Member.ReflectedType) &&
assignment.Expression.NodeType == ExpressionType.MemberInit))
{
Expression nestedEntry = CallMaterializer(
"ProjectionGetEntry",
entryParameterAtMemberInit,
Expression.Constant(assignment.Member.Name, typeof(string)));
ParameterExpression nestedEntryParameter = Expression.Parameter(
typeof(object),
"subentry" + this.identifierId++);
// Register the rewrite from the top to the entry if necessary.
ProjectionPath entryPath;
ExpressionAnnotation entryAnnotation;
if (this.annotations.TryGetValue(this.pathBuilder.ParameterEntryInScope, out entryAnnotation))
{
entryPath = new ProjectionPath(
(ParameterExpression)this.pathBuilder.LambdaParameterInScope,
this.pathBuilder.ExpectedParamTypeInScope,
entryParameterAtMemberInit);
entryPath.AddRange(entryAnnotation.Segment.StartPath);
}
else
{
entryPath = new ProjectionPath(
(ParameterExpression)this.pathBuilder.LambdaParameterInScope,
this.pathBuilder.ExpectedParamTypeInScope,
entryParameterAtMemberInit,
expressions.Skip(1));
}
ProjectionPathSegment nestedSegment = new ProjectionPathSegment(
entryPath,
assignment.Member.Name,
assignment.Member.ReflectedType);
entryPath.Add(nestedSegment);
string[] names = (entryPath.Where(m => m.Member != null).Select(m => m.Member)).ToArray();
this.annotations.Add(nestedEntryParameter, new ExpressionAnnotation() { Segment = nestedSegment });
this.pathBuilder.RegisterRewrite(this.pathBuilder.LambdaParameterInScope, names, nestedEntryParameter);
Expression e = this.Visit(assignment.Expression);
this.pathBuilder.RevokeRewrite(this.pathBuilder.LambdaParameterInScope, names);
this.annotations.Remove(nestedEntryParameter);
e = Expression.Convert(e, typeof(object));
ParameterExpression[] parameters =
new ParameterExpression[]
{
this.materializerExpression,
nestedEntryParameter,
expectedParameterForMembers,
};
propertyLambda = Expression.Lambda(e, parameters);
Expression[] nestedParams =
new Expression[]
{
this.materializerExpression,
nestedEntry,
expectedParameterForMembers,
};
var invokeParameters =
new ParameterExpression[]
{
this.materializerExpression,
(ParameterExpression)entryParameterAtMemberInit,
expectedParameterForMembers,
};
propertyLambda = Expression.Lambda(Expression.Invoke(propertyLambda, nestedParams), invokeParameters);
}
else
{
// We need an expression of object, which might require boxing.
Expression e = this.Visit(assignment.Expression);
e = Expression.Convert(e, typeof(object));
ParameterExpression[] parameters =
new ParameterExpression[]
{
this.materializerExpression,
entryParameterForMembers,
expectedParameterForMembers,
};
propertyLambda = Expression.Lambda(e, parameters);
}
#if TRACE_CLIENT_PROJECTIONS
Trace.WriteLine("Compiling lambda for " + assignment.Member.Name + ": " + propertyLambda);
#endif
propertyFunctions.Add((Func) propertyLambda.Compile());
}
// Revoke rewrites used for nested initialization.
for (int i = 1; i < expressions.Length; i++)
{
this.pathBuilder.RevokeRewrite(this.pathBuilder.LambdaParameterInScope, expressionNames);
this.annotations.Remove(entryToInitValue);
this.annotations.Remove(entryParameterForMembers);
}
Expression reboundExpression = CallMaterializer(
"ProjectionInitializeEntity",
this.materializerExpression,
entryToInitValue,
expectedParamValue,
projectedTypeExpression,
Expression.Constant(propertyNames.ToArray()),
Expression.Constant(propertyFunctions.ToArray()));
return Expression.Convert(reboundExpression, projectedType);
}
///
/// Creates an expression that gets the deepest entry that will be found on the
/// specified (for the target tree).
///
/// Path of expressions to walk.
/// An expression that invokes ProjectionGetEntry on the target tree.
private Expression GetDeepestEntry(Expression[] path)
{
Debug.Assert(path.Length > 1, "path.Length > 1");
Expression result = null;
int pathIndex = 1;
do
{
result = CallMaterializer(
"ProjectionGetEntry",
result ?? this.pathBuilder.ParameterEntryInScope,
Expression.Constant(((MemberExpression)path[pathIndex]).Member.Name, typeof(string)));
pathIndex++;
}
while (pathIndex < path.Length);
return result;
}
/// Gets an expression before its rewrite.
/// Expression to check.
/// The expression before normalization.
private Expression GetExpressionBeforeNormalization(Expression expression)
{
Debug.Assert(expression != null, "expression != null");
if (this.normalizerRewrites != null)
{
Expression original;
if (this.normalizerRewrites.TryGetValue(expression, out original))
{
expression = original;
}
}
return expression;
}
/// Rebinds the specified parameter expression as a path-based access.
/// Expression to rebind.
/// Annotation for the expression to rebind.
/// The rebound expression.
private Expression RebindParameter(Expression expression, ExpressionAnnotation annotation)
{
Debug.Assert(expression != null, "expression != null");
Debug.Assert(annotation != null, "annotation != null");
Expression result;
result = this.CallValueForPathWithType(
annotation.Segment.StartPath.RootEntry,
annotation.Segment.StartPath.ExpectedRootType,
annotation.Segment.StartPath,
expression.Type);
// Refresh the annotation so the next one that comes along
// doesn't start off with an already-written path.
ProjectionPath parameterPath = new ProjectionPath(
annotation.Segment.StartPath.Root,
annotation.Segment.StartPath.ExpectedRootType,
annotation.Segment.StartPath.RootEntry);
ProjectionPathSegment parameterSegment = new ProjectionPathSegment(parameterPath, null, null);
parameterPath.Add(parameterSegment);
this.annotations[expression] = new ExpressionAnnotation() { Segment = parameterSegment };
return result;
}
/// Rebinds the specified member access expression into a path-based value retrieval method call.
/// Member expression.
/// Annotation for the base portion of the expression.
/// A rebound expression.
private Expression RebindMemberAccess(MemberExpression m, ExpressionAnnotation baseAnnotation)
{
Debug.Assert(m != null, "m != null");
Debug.Assert(baseAnnotation != null, "baseAnnotation != null");
ProjectionPathSegment memberSegment;
// If we are in nested member-init, we rewrite the property
// accessors that are in the form of top.nested.id to
// nested.id.
Expression baseSourceExpression = m.Expression;
Expression result = this.pathBuilder.GetRewrite(baseSourceExpression);
if (result != null)
{
Expression baseTypeExpression = Expression.Constant(baseSourceExpression.Type, typeof(Type));
ProjectionPath nestedPath = new ProjectionPath(result as ParameterExpression, baseTypeExpression, result);
ProjectionPathSegment nestedSegment = new ProjectionPathSegment(nestedPath, m.Member.Name, m.Type);
nestedPath.Add(nestedSegment);
result = this.CallValueForPathWithType(result, baseTypeExpression, nestedPath, m.Type);
}
else
{
// This actually modifies the path for the underlying
// segments, but that shouldn't be a problem. Actually
// we should be able to remove it from the dictionary.
// There should be no aliasing problems, because
// annotations always come from target expression
// that are generated anew (except parameters,
// but those)
memberSegment = new ProjectionPathSegment(baseAnnotation.Segment.StartPath, m.Member.Name, m.Type);
baseAnnotation.Segment.StartPath.Add(memberSegment);
result = this.CallValueForPathWithType(
baseAnnotation.Segment.StartPath.RootEntry,
baseAnnotation.Segment.StartPath.ExpectedRootType,
baseAnnotation.Segment.StartPath,
m.Type);
}
return result;
}
/// Rewrites a new statement for DataServiceCollection so the paging information
/// is preserved in the materializer.
/// NewExpression to create a collection
/// The rewritten expression.
private NewExpression RebindNewExpressionForDataServiceCollectionOfT(NewExpression nex)
{
Debug.Assert(nex != null, "nex != null");
Debug.Assert(
ResourceBinder.PatternRules.MatchNewDataServiceCollectionOfT(nex),
"Called should have checked that the 'new' was for our collection type");
NewExpression result = base.VisitNew(nex);
ExpressionAnnotation annotation = null;
if (result != null)
{
ConstructorInfo constructorInfo =
nex.Type.GetConstructors(BindingFlags.NonPublic | BindingFlags.Instance).First(
c => c.GetParameters().Length == 7 && c.GetParameters()[0].ParameterType == typeof(object));
Type enumerable = typeof(IEnumerable<>).MakeGenericType(nex.Type.GetGenericArguments()[0]);
if (result.Arguments.Count == 1 && result.Constructor == nex.Type.GetConstructor(new[] { enumerable }) &&
this.annotations.TryGetValue(result.Arguments[0], out annotation))
{
// DataServiceCollection(
// IEnumerable items)
// ->
// DataServiceCollection(materializer, null, items, TrackingMode.AutoChangeTracking, null, null, null)
result = Expression.New(
constructorInfo,
this.materializerExpression,
Expression.Constant(null, typeof(DataServiceContext)),
result.Arguments[0],
Expression.Constant(TrackingMode.AutoChangeTracking, typeof(TrackingMode)),
Expression.Constant(null, typeof(string)),
Expression.Constant(null, typeof(Func)),
Expression.Constant(null, typeof(Func)));
}
else if (result.Arguments.Count == 2 &&
this.annotations.TryGetValue(result.Arguments[0], out annotation))
{
// DataServiceCollection(
// IEnumerable items,
// TrackingMode trackingMode)
// ->
// DataServiceCollection(materializer, null, items, trackingMode, null, null, null)
result = Expression.New(
constructorInfo,
this.materializerExpression,
Expression.Constant(null, typeof(DataServiceContext)),
result.Arguments[0], // items
result.Arguments[1], // TrackingMode
Expression.Constant(null, typeof(string)),
Expression.Constant(null, typeof(Func)),
Expression.Constant(null, typeof(Func)));
}
else if (result.Arguments.Count == 5 &&
this.annotations.TryGetValue(result.Arguments[0], out annotation))
{
// DataServiceCollection(
// IEnumerable items,
// TrackingMode trackingMode,
// string entitySet,
// Func<> entityChangedCallback,
// Func<> entityCollectionChangedCallback)
// ->
// DataServiceCollection(materializer, null, items, trackingMode,
// entitySet, entityChangedCallback, entityCollectionChangedCallback)
result = Expression.New(
constructorInfo,
this.materializerExpression,
Expression.Constant(null, typeof(DataServiceContext)),
result.Arguments[0], // items
result.Arguments[1], // TrackingMode
result.Arguments[2], // entityset name
result.Arguments[3], // entity changed cb
result.Arguments[4]); // collection changed cb
}
else if (result.Arguments.Count == 6 &&
typeof(DataServiceContext).IsAssignableFrom(result.Arguments[0].Type) &&
this.annotations.TryGetValue(result.Arguments[1], out annotation))
{
// DataServiceCollection(
// DataServiceContext context,
// IEnumerable items,
// TrackingMode trackingMode,
// string entitySet,
// Func<> entityChangedCallback,
// Func<> entityCollectionChangedCallback)
// ->
// DataServiceCollection(materializer, context, items, trackingMode,
// entitySet, entityChangedCallback, entityCollectionChangedCallback)
result = Expression.New(
constructorInfo,
this.materializerExpression,
result.Arguments[0], // context
result.Arguments[1], // items
result.Arguments[2], // trackingMode
result.Arguments[3], // entityset name
result.Arguments[4], // entity changed cb
result.Arguments[5]); // collection changed cb
}
}
if (annotation != null)
{
// Propagate the annotation of the "items" parameter (the enumerable) as the annotation
// of the DataServiceCollection, since it now represents the same thing.
this.annotations.Add(result, annotation);
}
// Note that we end up just falling through without changing anything for
// constructors of DataServiceCollection that aren't correlated (i.e. don't take
// an enumerable in the input).
return result;
}
/// Rewrites a call to Select() by adding to the current paths to project out.
/// Call expression.
/// Expression with annotated path to include in member binding.
private Expression RebindMethodCallForMemberSelect(MethodCallExpression call)
{
Debug.Assert(call != null, "call != null");
Debug.Assert(call.Method.Name == "Select", "call.Method.Name == 'Select'");
Debug.Assert(call.Object == null, "call.Object == null -- otherwise this isn't a call to a static Select method");
Debug.Assert(call.Arguments.Count == 2, "call.Arguments.Count == 2 -- otherwise this isn't the expected Select() call on IQueryable");
// Get the path for the parameter value that will be used in the Select lambda.
Expression result = null;
Expression parameterSource = this.Visit(call.Arguments[0]);
ExpressionAnnotation annotation;
this.annotations.TryGetValue(parameterSource, out annotation);
// It's possibly that we haven't annotated this argument, in which
// case we don't care about this select, eg new { a = new int[] {1}.Select(i=>i+1).First() }
if (annotation != null)
{
// With this information from an annotation:
// {t->*.Players}
//
// Call this lambda:
// {(mat, entry1, type1) => Convert(ProjectionValueForPath(mat, entry1, type1, p->*.FirstName))}
//
// Annotating the intermediate expressions so we mark them
// as rewrites and we know to route them through materializer
// helpers, eg to preserve paging information.
Expression selectorExpression = this.Visit(call.Arguments[1]);
Type returnElementType = call.Method.ReturnType.GetGenericArguments()[0];
result = CallMaterializer(
"ProjectionSelect",
this.materializerExpression,
this.pathBuilder.ParameterEntryInScope,
this.pathBuilder.ExpectedParamTypeInScope,
Expression.Constant(returnElementType, typeof(Type)),
Expression.Constant(annotation.Segment.StartPath, typeof(object)),
selectorExpression);
this.annotations.Add(result, annotation);
result = CallMaterializerWithType(
"EnumerateAsElementType",
new Type[] { returnElementType },
result);
this.annotations.Add(result, annotation);
}
if (result == null)
{
result = base.VisitMethodCall(call);
}
return result;
}
/// Rewrites a call to ToList in the specified method.
/// Call expression.
/// Expression with annotated path to include in member binding.
///
/// All that is necessary here is to rewrite the call to Select() and indicate
/// that the target type is a given List<T>.
///
///
private Expression RebindMethodCallForMemberToList(MethodCallExpression call)
{
Debug.Assert(call != null, "call != null");
Debug.Assert(call.Object == null, "call.Object == null -- otherwise this isn't a call to a static ToList method");
Debug.Assert(call.Method.Name == "ToList", "call.Method.Name == 'ToList'");
// Wrap the source to the .ToList() call if it's our rewrite.
Debug.Assert(call.Arguments.Count == 1, "call.Arguments.Count == 1 -- otherwise this isn't the expected ToList() call on IEnumerable");
Expression result = this.Visit(call.Arguments[0]);
ExpressionAnnotation annotation;
if (this.annotations.TryGetValue(result, out annotation))
{
result = this.TypedEnumerableToList(result, call.Type);
this.annotations.Add(result, annotation);
}
return result;
}
/// Rewrites a method call used in a sequence method (possibly over entity types).
/// Call expression.
/// Expression that can be called directly to yield the expected value.
private Expression RebindMethodCallForNewSequence(MethodCallExpression call)
{
Debug.Assert(call != null, "call != null");
Debug.Assert(ProjectionAnalyzer.IsMethodCallAllowedEntitySequence(call), "ProjectionAnalyzer.IsMethodCallAllowedEntitySequence(call)");
Debug.Assert(call.Object == null, "call.Object == null -- otherwise this isn't the supported Select or ToList methods");
// The only expressions that require rewriting are:
// - [null].Select(entity-type-based-expression, lambda)
// - [null].ToList(entity-type-enumeration)
//
// All other expressions can be visited normally.
Expression result = null;
if (call.Method.Name == "Select")
{
Debug.Assert(call.Arguments.Count == 2, "call.Arguments.Count == 2 -- otherwise this isn't the argument we expected");
// Get the path for the parameter value that will be used in the Select lambda.
Expression parameterSource = this.Visit(call.Arguments[0]);
ExpressionAnnotation annotation;
this.annotations.TryGetValue(parameterSource, out annotation);
// It's possibly that we haven't annotated this argument, in which
// case we don't care about this select, eg new { a = new int[] {1}.Select(i=>i+1).First() }
if (annotation != null)
{
// With this information from an annotation:
// {t->*.Players}
//
// Call this lambda:
// {(mat, entry1, type1) => Convert(ProjectionValueForPath(mat, entry1, type1, p->*.FirstName))}
Expression selectorExpression = this.Visit(call.Arguments[1]);
Type returnElementType = call.Method.ReturnType.GetGenericArguments()[0];
result = CallMaterializer(
"ProjectionSelect",
this.materializerExpression,
this.pathBuilder.ParameterEntryInScope,
this.pathBuilder.ExpectedParamTypeInScope,
Expression.Constant(returnElementType, typeof(Type)),
Expression.Constant(annotation.Segment.StartPath, typeof(object)),
selectorExpression);
this.annotations.Add(result, annotation);
result = CallMaterializerWithType(
"EnumerateAsElementType",
new Type[] { returnElementType },
result);
this.annotations.Add(result, annotation);
}
}
else
{
Debug.Assert(call.Method.Name == "ToList", "call.Method.Name == 'ToList'");
// Annotate the source to the .ToList() call.
Expression source = this.Visit(call.Arguments[0]);
ExpressionAnnotation annotation;
if (this.annotations.TryGetValue(source, out annotation))
{
result = this.TypedEnumerableToList(source, call.Type);
this.annotations.Add(result, annotation);
}
}
if (result == null)
{
result = base.VisitMethodCall(call);
}
return result;
}
/// Returns a method call that returns a list from a typed enumerable.
/// Expression to convert.
/// Target type to return.
/// The new expression.
private Expression TypedEnumerableToList(Expression source, Type targetType)
{
Debug.Assert(source != null, "source != null");
Debug.Assert(targetType != null, "targetType != null");
//
Type enumeratedType = source.Type.GetGenericArguments()[0];
Type listElementType = targetType.GetGenericArguments()[0];
// Return the annotated expression.
Expression result = CallMaterializerWithType(
"ListAsElementType",
new Type[] { enumeratedType, listElementType },
this.materializerExpression,
source);
return result;
}
#endregion Private methods.
#region Inner types.
/// Annotates an expression, typically from the target tree.
internal class ExpressionAnnotation
{
/// Segment that marks the path found to an expression.
internal ProjectionPathSegment Segment
{
get;
set;
}
}
#endregion Inner types.
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.