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//
// CombineQueryExpressions.cs
//
// Modified by Luís Reis <luiscubal@gmail.com> (Copyright (C) 2013)
//
// Copyright header of the original version follows:
//
// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
using System;
using System.Linq;
using ICSharpCode.NRefactory.CSharp;
using ICSharpCode.NRefactory.PatternMatching;
namespace ICSharpCode.NRefactory.CSharp
{
/// <summary>
/// Combines query expressions and removes transparent identifiers.
/// </summary>
public class CombineQueryExpressions
{
static readonly InvocationExpression castPattern = new InvocationExpression {
Target = new MemberReferenceExpression {
Target = new AnyNode("inExpr"),
MemberName = "Cast",
TypeArguments = { new AnyNode("targetType") }
}};
public string CombineQuery(AstNode node, AstNode rootQuery = null)
{
if (rootQuery == null) {
rootQuery = node;
}
QueryExpression query = node as QueryExpression;
if (query != null) {
string continuationIdentifier = null;
foreach (var clause in query.Clauses) {
var continuation = clause as QueryContinuationClause;
if (continuation != null) {
CombineQuery(continuation.PrecedingQuery);
}
var from = clause as QueryFromClause;
if (from != null) {
continuationIdentifier = CombineQuery(from.Expression, rootQuery);
}
}
QueryFromClause fromClause = (QueryFromClause)query.Clauses.First();
QueryExpression innerQuery = fromClause.Expression as QueryExpression;
if (innerQuery != null) {
continuationIdentifier = continuationIdentifier ?? ((QueryFromClause)innerQuery.Clauses.First()).Identifier;
string transparentIdentifier;
if (TryRemoveTransparentIdentifier(query, fromClause, innerQuery, continuationIdentifier, out transparentIdentifier)) {
RemoveTransparentIdentifierReferences(rootQuery, transparentIdentifier);
} else if (fromClause.Type.IsNull) {
QueryContinuationClause continuation = new QueryContinuationClause();
continuation.PrecedingQuery = innerQuery.Detach();
continuation.Identifier = fromClause.Identifier;
fromClause.ReplaceWith(continuation);
}
return transparentIdentifier;
} else {
Match m = castPattern.Match(fromClause.Expression);
if (m.Success) {
fromClause.Type = m.Get<AstType>("targetType").Single().Detach();
fromClause.Expression = m.Get<Expression>("inExpr").Single().Detach();
}
}
}
return null;
}
static readonly QuerySelectClause selectTransparentIdentifierPattern = new QuerySelectClause {
Expression = new AnonymousTypeCreateExpression {
Initializers = {
new AnyNode("nae1"),
new AnyNode("nae2")
}
}
};
bool TryRemoveTransparentIdentifier(QueryExpression query, QueryFromClause fromClause, QueryExpression innerQuery, string continuationIdentifier, out string transparentIdentifier)
{
transparentIdentifier = fromClause.Identifier;
Match match = selectTransparentIdentifierPattern.Match(innerQuery.Clauses.Last());
if (!match.Success)
return false;
QuerySelectClause selectClause = (QuerySelectClause)innerQuery.Clauses.Last();
Expression nae1 = match.Get<Expression>("nae1").SingleOrDefault();
string nae1Name = ExtractExpressionName(ref nae1);
if (nae1Name == null)
return false;
Expression nae2 = match.Get<Expression>("nae2").SingleOrDefault();
string nae2Name = ExtractExpressionName(ref nae2);
if (nae2Name == null)
return false;
bool introduceLetClause = true;
var nae1Identifier = nae1 as IdentifierExpression;
var nae2Identifier = nae2 as IdentifierExpression;
if (nae1Identifier != null && nae2Identifier != null && nae1Identifier.Identifier == nae1Name && nae2Identifier.Identifier == nae2Name) {
introduceLetClause = false;
}
if (nae1Name != continuationIdentifier) {
if (nae2Name == continuationIdentifier) {
//Members are in reversed order
string tempName = nae1Name;
Expression tempNae = nae1;
nae1Name = nae2Name;
nae1 = nae2;
nae2Name = tempName;
nae2 = tempNae;
} else {
return false;
}
}
if (introduceLetClause && innerQuery.Clauses.OfType<QueryFromClause>().Any(from => from.Identifier == nae2Name)) {
return false;
}
if (introduceLetClause && innerQuery.Clauses.OfType<QueryJoinClause>().Any(join => join.JoinIdentifier == nae2Name)) {
return false;
}
// from * in (from x in ... select new { x = x, y = expr }) ...
// =>
// from x in ... let y = expr ...
fromClause.Remove();
selectClause.Remove();
// Move clauses from innerQuery to query
QueryClause insertionPos = null;
foreach (var clause in innerQuery.Clauses) {
query.Clauses.InsertAfter(insertionPos, insertionPos = clause.Detach());
}
if (introduceLetClause) {
query.Clauses.InsertAfter(insertionPos, new QueryLetClause { Identifier = nae2Name, Expression = nae2.Detach() });
}
return true;
}
/// <summary>
/// Removes all occurrences of transparent identifiers
/// </summary>
void RemoveTransparentIdentifierReferences(AstNode node, string transparentIdentifier)
{
foreach (AstNode child in node.Children) {
RemoveTransparentIdentifierReferences(child, transparentIdentifier);
}
MemberReferenceExpression mre = node as MemberReferenceExpression;
if (mre != null) {
IdentifierExpression ident = mre.Target as IdentifierExpression;
if (ident != null && ident.Identifier == transparentIdentifier) {
IdentifierExpression newIdent = new IdentifierExpression(mre.MemberName);
mre.TypeArguments.MoveTo(newIdent.TypeArguments);
newIdent.CopyAnnotationsFrom(mre);
newIdent.RemoveAnnotations<PropertyDeclaration>(); // remove the reference to the property of the anonymous type
mre.ReplaceWith(newIdent);
return;
} else if (mre.MemberName == transparentIdentifier) {
var newVar = mre.Target.Detach();
newVar.CopyAnnotationsFrom(mre);
newVar.RemoveAnnotations<PropertyDeclaration>(); // remove the reference to the property of the anonymous type
mre.ReplaceWith(newVar);
return;
}
}
}
string ExtractExpressionName(ref Expression expr)
{
NamedExpression namedExpr = expr as NamedExpression;
if (namedExpr != null) {
expr = namedExpr.Expression;
return namedExpr.Name;
}
IdentifierExpression identifier = expr as IdentifierExpression;
if (identifier != null) {
return identifier.Identifier;
}
MemberReferenceExpression memberRef = expr as MemberReferenceExpression;
if (memberRef != null) {
return memberRef.MemberName;
}
return null;
}
}
}
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