2 using System.Collections;
3 using System.Collections.Generic;
4 using System.Collections.ObjectModel;
5 using System.Linq.Expressions;
6 using System.Reflection;
9 // Include Silverlight's managed resources
14 namespace System.Linq {
16 // Must remain public for Silverlight
17 public abstract class EnumerableQuery {
18 internal abstract Expression Expression { get; }
19 internal abstract IEnumerable Enumerable { get; }
20 internal static IQueryable Create(Type elementType, IEnumerable sequence){
21 Type seqType = typeof(EnumerableQuery<>).MakeGenericType(elementType);
23 return (IQueryable) Activator.CreateInstance(seqType, sequence);
25 return (IQueryable) Activator.CreateInstance(seqType, BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic, null, new object[] {sequence}, null);
29 internal static IQueryable Create(Type elementType, Expression expression) {
30 Type seqType = typeof(EnumerableQuery<>).MakeGenericType(elementType);
32 return (IQueryable) Activator.CreateInstance(seqType, expression);
34 return (IQueryable) Activator.CreateInstance(seqType, BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic, null, new object[] {expression}, null);
39 // Must remain public for Silverlight
40 public class EnumerableQuery<T> : EnumerableQuery, IOrderedQueryable<T>, IQueryable, IQueryProvider, IEnumerable<T>, IEnumerable {
41 Expression expression;
42 IEnumerable<T> enumerable;
44 IQueryProvider IQueryable.Provider {
46 return (IQueryProvider)this;
50 // Must remain public for Silverlight
51 public EnumerableQuery(IEnumerable<T> enumerable) {
52 this.enumerable = enumerable;
53 this.expression = Expression.Constant(this);
56 // Must remain public for Silverlight
57 public EnumerableQuery(Expression expression) {
58 this.expression = expression;
61 internal override Expression Expression {
62 get { return this.expression; }
65 internal override IEnumerable Enumerable {
66 get { return this.enumerable; }
69 Expression IQueryable.Expression {
70 get { return this.expression; }
73 Type IQueryable.ElementType {
74 get { return typeof(T); }
77 IQueryable IQueryProvider.CreateQuery(Expression expression){
78 if (expression == null)
79 throw Error.ArgumentNull("expression");
80 Type iqType = TypeHelper.FindGenericType(typeof(IQueryable<>), expression.Type);
82 throw Error.ArgumentNotValid("expression");
83 return EnumerableQuery.Create(iqType.GetGenericArguments()[0], expression);
86 IQueryable<S> IQueryProvider.CreateQuery<S>(Expression expression){
87 if (expression == null)
88 throw Error.ArgumentNull("expression");
89 if (!typeof(IQueryable<S>).IsAssignableFrom(expression.Type)){
90 throw Error.ArgumentNotValid("expression");
92 return new EnumerableQuery<S>(expression);
95 // Baselining as Safe for Mix demo so that interface can be transparent. Marking this
96 // critical (which was the original annotation when porting to silverlight) would violate
97 // fxcop security rules if the interface isn't also critical. However, transparent code
98 // can't access this anyway for Mix since we're not exposing AsQueryable().
99 // Microsoft: the above assertion no longer holds. Now making AsQueryable() public again
100 // the security fallout of which will need to be re-examined.
101 object IQueryProvider.Execute(Expression expression){
102 if (expression == null)
103 throw Error.ArgumentNull("expression");
105 Type execType = typeof(EnumerableExecutor<>).MakeGenericType(expression.Type);
107 return EnumerableExecutor.Create(expression).ExecuteBoxed();
111 S IQueryProvider.Execute<S>(Expression expression){
112 if (expression == null)
113 throw Error.ArgumentNull("expression");
114 if (!typeof(S).IsAssignableFrom(expression.Type))
115 throw Error.ArgumentNotValid("expression");
116 return new EnumerableExecutor<S>(expression).Execute();
119 IEnumerator IEnumerable.GetEnumerator() {
120 return this.GetEnumerator();
123 IEnumerator<T> IEnumerable<T>.GetEnumerator() {
124 return this.GetEnumerator();
127 IEnumerator<T> GetEnumerator() {
128 if (this.enumerable == null) {
129 EnumerableRewriter rewriter = new EnumerableRewriter();
130 Expression body = rewriter.Visit(this.expression);
131 Expression<Func<IEnumerable<T>>> f = Expression.Lambda<Func<IEnumerable<T>>>(body, (IEnumerable<ParameterExpression>)null);
132 this.enumerable = f.Compile()();
134 return this.enumerable.GetEnumerator();
137 public override string ToString() {
138 ConstantExpression c = this.expression as ConstantExpression;
139 if (c != null && c.Value == this) {
140 if (this.enumerable != null)
141 return this.enumerable.ToString();
144 return this.expression.ToString();
148 // Must remain public for Silverlight
149 public abstract class EnumerableExecutor {
150 internal abstract object ExecuteBoxed();
152 internal static EnumerableExecutor Create(Expression expression) {
153 Type execType = typeof(EnumerableExecutor<>).MakeGenericType(expression.Type);
155 return (EnumerableExecutor)Activator.CreateInstance(execType, expression);
157 return (EnumerableExecutor)Activator.CreateInstance(execType, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, new object[] { expression }, null);
162 // Must remain public for Silverlight
163 public class EnumerableExecutor<T> : EnumerableExecutor{
164 Expression expression;
167 // Must remain public for Silverlight
168 public EnumerableExecutor(Expression expression){
169 this.expression = expression;
172 internal override object ExecuteBoxed() {
173 return this.Execute();
176 internal T Execute(){
177 if (this.func == null){
178 EnumerableRewriter rewriter = new EnumerableRewriter();
179 Expression body = rewriter.Visit(this.expression);
180 Expression<Func<T>> f = Expression.Lambda<Func<T>>(body, (IEnumerable<ParameterExpression>)null);
181 this.func = f.Compile();
188 internal class EnumerableRewriter : OldExpressionVisitor {
190 internal EnumerableRewriter() {
193 internal override Expression VisitMethodCall(MethodCallExpression m) {
194 Expression obj = this.Visit(m.Object);
195 ReadOnlyCollection<Expression> args = this.VisitExpressionList(m.Arguments);
197 // check for args changed
198 if (obj != m.Object || args != m.Arguments) {
200 Expression[] argArray = args.ToArray();
202 Type[] typeArgs = (m.Method.IsGenericMethod) ? m.Method.GetGenericArguments() : null;
204 if ((m.Method.IsStatic || m.Method.DeclaringType.IsAssignableFrom(obj.Type))
205 && ArgsMatch(m.Method, args, typeArgs)) {
206 // current method is still valid
207 return Expression.Call(obj, m.Method, args);
209 else if (m.Method.DeclaringType == typeof(Queryable)) {
210 // convert Queryable method to Enumerable method
211 MethodInfo seqMethod = FindEnumerableMethod(m.Method.Name, args, typeArgs);
212 args = this.FixupQuotedArgs(seqMethod, args);
213 return Expression.Call(obj, seqMethod, args);
216 // rebind to new method
217 BindingFlags flags = BindingFlags.Static | (m.Method.IsPublic ? BindingFlags.Public : BindingFlags.NonPublic);
218 MethodInfo method = FindMethod(m.Method.DeclaringType, m.Method.Name, args, typeArgs, flags);
219 args = this.FixupQuotedArgs(method, args);
220 return Expression.Call(obj, method, args);
226 private ReadOnlyCollection<Expression> FixupQuotedArgs(MethodInfo mi, ReadOnlyCollection<Expression> argList) {
227 ParameterInfo[] pis = mi.GetParameters();
228 if (pis.Length > 0) {
229 List<Expression> newArgs = null;
230 for (int i = 0, n = pis.Length; i < n; i++) {
231 Expression arg = argList[i];
232 ParameterInfo pi = pis[i];
233 arg = FixupQuotedExpression(pi.ParameterType, arg);
234 if (newArgs == null && arg != argList[i]) {
235 newArgs = new List<Expression>(argList.Count);
236 for (int j = 0; j < i; j++) {
237 newArgs.Add(argList[j]);
240 if (newArgs != null) {
245 argList = newArgs.ToReadOnlyCollection();
250 private Expression FixupQuotedExpression(Type type, Expression expression) {
251 Expression expr = expression;
253 if (type.IsAssignableFrom(expr.Type))
255 if (expr.NodeType != ExpressionType.Quote)
257 expr = ((UnaryExpression)expr).Operand;
259 if (!type.IsAssignableFrom(expr.Type) && type.IsArray && expr.NodeType == ExpressionType.NewArrayInit) {
260 Type strippedType = StripExpression(expr.Type);
261 if (type.IsAssignableFrom(strippedType)) {
262 Type elementType = type.GetElementType();
263 NewArrayExpression na = (NewArrayExpression)expr;
264 List<Expression> exprs = new List<Expression>(na.Expressions.Count);
265 for (int i = 0, n = na.Expressions.Count; i < n; i++) {
266 exprs.Add(this.FixupQuotedExpression(elementType, na.Expressions[i]));
268 expression = Expression.NewArrayInit(elementType, exprs);
274 internal override Expression VisitLambda(LambdaExpression lambda) {
278 private static Type GetPublicType(Type t)
280 // If we create a constant explicitly typed to be a private nested type,
281 // such as Lookup<,>.Grouping or a compiler-generated iterator class, then
282 // we cannot use the expression tree in a context which has only execution
283 // permissions. We should endeavour to translate constants into
284 // new constants which have public types.
285 if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Lookup<,>.Grouping))
286 return typeof(IGrouping<,>).MakeGenericType(t.GetGenericArguments());
287 if (!t.IsNestedPrivate)
289 foreach (Type iType in t.GetInterfaces())
291 if (iType.IsGenericType && iType.GetGenericTypeDefinition() == typeof(IEnumerable<>))
294 if (typeof(IEnumerable).IsAssignableFrom(t))
295 return typeof(IEnumerable);
299 internal override Expression VisitConstant(ConstantExpression c) {
300 EnumerableQuery sq = c.Value as EnumerableQuery;
302 if (sq.Enumerable != null)
304 Type t = GetPublicType(sq.Enumerable.GetType());
305 return Expression.Constant(sq.Enumerable, t);
307 return this.Visit(sq.Expression);
312 internal override Expression VisitParameter(ParameterExpression p) {
316 private static volatile ILookup<string, MethodInfo> _seqMethods;
317 static MethodInfo FindEnumerableMethod(string name, ReadOnlyCollection<Expression> args, params Type[] typeArgs) {
318 if (_seqMethods == null) {
319 _seqMethods = typeof(Enumerable).GetMethods(BindingFlags.Static|BindingFlags.Public).ToLookup(m => m.Name);
321 MethodInfo mi = _seqMethods[name].FirstOrDefault(m => ArgsMatch(m, args, typeArgs));
323 throw Error.NoMethodOnTypeMatchingArguments(name, typeof(Enumerable));
324 if (typeArgs != null)
325 return mi.MakeGenericMethod(typeArgs);
329 internal static MethodInfo FindMethod(Type type, string name, ReadOnlyCollection<Expression> args, Type[] typeArgs, BindingFlags flags) {
330 MethodInfo[] methods = type.GetMethods(flags).Where(m => m.Name == name).ToArray();
331 if (methods.Length == 0)
332 throw Error.NoMethodOnType(name, type);
333 MethodInfo mi = methods.FirstOrDefault(m => ArgsMatch(m, args, typeArgs));
335 throw Error.NoMethodOnTypeMatchingArguments(name, type);
336 if (typeArgs != null)
337 return mi.MakeGenericMethod(typeArgs);
341 private static bool ArgsMatch(MethodInfo m, ReadOnlyCollection<Expression> args, Type[] typeArgs) {
342 ParameterInfo[] mParams = m.GetParameters();
343 if (mParams.Length != args.Count)
345 if (!m.IsGenericMethod && typeArgs != null && typeArgs.Length > 0) {
348 if (!m.IsGenericMethodDefinition && m.IsGenericMethod && m.ContainsGenericParameters) {
349 m = m.GetGenericMethodDefinition();
351 if (m.IsGenericMethodDefinition) {
352 if (typeArgs == null || typeArgs.Length == 0)
354 if (m.GetGenericArguments().Length != typeArgs.Length)
356 m = m.MakeGenericMethod(typeArgs);
357 mParams = m.GetParameters();
359 for (int i = 0, n = args.Count; i < n; i++) {
360 Type parameterType = mParams[i].ParameterType;
361 if (parameterType == null)
363 if (parameterType.IsByRef)
364 parameterType = parameterType.GetElementType();
365 Expression arg = args[i];
366 if (!parameterType.IsAssignableFrom(arg.Type)) {
367 if (arg.NodeType == ExpressionType.Quote) {
368 arg = ((UnaryExpression)arg).Operand;
370 if (!parameterType.IsAssignableFrom(arg.Type) &&
371 !parameterType.IsAssignableFrom(StripExpression(arg.Type))) {
379 private static Type StripExpression(Type type) {
380 bool isArray = type.IsArray;
381 Type tmp = isArray ? type.GetElementType() : type;
382 Type eType = TypeHelper.FindGenericType(typeof(Expression<>), tmp);
384 tmp = eType.GetGenericArguments()[0];
386 int rank = type.GetArrayRank();
387 return (rank == 1) ? tmp.MakeArrayType() : tmp.MakeArrayType(rank);