source: branches/2922-DataCompletenessChartPerf/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Parser/mcs/complete.cs

//
// complete.cs: Expression that are used for completion suggestions.
//
// Author:
//   Miguel de Icaza (miguel@ximian.com)
//   Marek Safar (marek.safar@gmail.com)
//
// Copyright 2001, 2002, 2003 Ximian, Inc.
// Copyright 2003-2009 Novell, Inc.
// Copyright 2011 Xamarin Inc
//
// Completion* classes derive from ExpressionStatement as this allows
// them to pass through the parser in many conditions that require
// statements even when the expression is incomplete (for example
// completing inside a lambda
//
using System.Collections.Generic;
using System.Linq;

namespace Mono.CSharp {

  //
  // A common base class for Completing expressions, it
  // is just a very simple ExpressionStatement
  //
  public abstract class CompletingExpression : ExpressionStatement
  {
    public static void AppendResults (List<string> results, string prefix, IEnumerable<string> names)
    {
      foreach (string name in names) {
        if (name == null)
          continue;

        if (prefix != null && !name.StartsWith (prefix))
          continue;

        if (results.Contains (name))
          continue;

        if (prefix != null)
          results.Add (name.Substring (prefix.Length));
        else
          results.Add (name);
      }
    }

    public override bool ContainsEmitWithAwait ()
    {
      return false;
    }

    public override Expression CreateExpressionTree (ResolveContext ec)
    {
      return null;
    }

    public override void EmitStatement (EmitContext ec)
    {
      // Do nothing
    }

    public override void Emit (EmitContext ec)
    {
      // Do nothing
    }
  }
  
  public class CompletionSimpleName : CompletingExpression {
    public string Prefix;
    
    public CompletionSimpleName (string prefix, Location l)
    {
      this.loc = l;
      this.Prefix = prefix;
    }
    
    protected override Expression DoResolve (ResolveContext ec)
    {
      var results = new List<string> ();

      ec.CurrentMemberDefinition.GetCompletionStartingWith (Prefix, results);

      throw new CompletionResult (Prefix, results.Distinct ().Select (l => l.Substring (Prefix.Length)).ToArray ());
    }

    protected override void CloneTo (CloneContext clonectx, Expression t)
    {
      // Nothing
    }
  }
  
  public class CompletionMemberAccess : CompletingExpression {
    Expression expr;
    string partial_name;
    TypeArguments targs;
    
    public CompletionMemberAccess (Expression e, string partial_name, Location l)
    {
      this.expr = e;
      this.loc = l;
      this.partial_name = partial_name;
    }

    public CompletionMemberAccess (Expression e, string partial_name, TypeArguments targs, Location l)
    {
      this.expr = e;
      this.loc = l;
      this.partial_name = partial_name;
      this.targs = targs;
    }
    
    protected override Expression DoResolve (ResolveContext rc)
    {
      var sn = expr as SimpleName;
      const ResolveFlags flags = ResolveFlags.VariableOrValue | ResolveFlags.Type;

      if (sn != null) {
        expr = sn.LookupNameExpression (rc, MemberLookupRestrictions.ReadAccess | MemberLookupRestrictions.ExactArity);

        //
        // Resolve expression which does have type set as we need expression type
        // with disable flow analysis as we don't know whether left side expression
        // is used as variable or type
        //
        if (expr is VariableReference || expr is ConstantExpr || expr is Linq.TransparentMemberAccess) {
          expr = expr.Resolve (rc);
        } else if (expr is TypeParameterExpr) {
          expr.Error_UnexpectedKind (rc, flags, sn.Location);
          expr = null;
        }
      } else {
        expr = expr.Resolve (rc, flags);
      }

      if (expr == null)
        return null;

      TypeSpec expr_type = expr.Type;
      if (expr_type.IsPointer || expr_type.Kind == MemberKind.Void || expr_type == InternalType.NullLiteral || expr_type == InternalType.AnonymousMethod) {
        expr.Error_OperatorCannotBeApplied (rc, loc, ".", expr_type);
        return null;
      }

      if (targs != null) {
        if (!targs.Resolve (rc))
          return null;
      }

      var results = new List<string> ();
      var nexpr = expr as NamespaceExpression;
      if (nexpr != null) {
        string namespaced_partial;

        if (partial_name == null)
          namespaced_partial = nexpr.Namespace.Name;
        else
          namespaced_partial = nexpr.Namespace.Name + "." + partial_name;

        rc.CurrentMemberDefinition.GetCompletionStartingWith (namespaced_partial, results);
        if (partial_name != null)
          results = results.Select (l => l.Substring (partial_name.Length)).ToList ();
      } else {
        var r = MemberCache.GetCompletitionMembers (rc, expr_type, partial_name).Select (l => l.Name);
        AppendResults (results, partial_name, r);
      }

      throw new CompletionResult (partial_name == null ? "" : partial_name, results.Distinct ().ToArray ());
    }

    protected override void CloneTo (CloneContext clonectx, Expression t)
    {
      CompletionMemberAccess target = (CompletionMemberAccess) t;

      if (targs != null)
        target.targs = targs.Clone ();

      target.expr = expr.Clone (clonectx);
    }
  }

  public class CompletionElementInitializer : CompletingExpression {
    string partial_name;
    
    public CompletionElementInitializer (string partial_name, Location l)
    {
      this.partial_name = partial_name;
      this.loc = l;
    }
    
    protected override Expression DoResolve (ResolveContext ec)
    {
      var members = MemberCache.GetCompletitionMembers (ec, ec.CurrentInitializerVariable.Type, partial_name);

// TODO: Does this mean exact match only ?
//      if (partial_name != null && results.Count > 0 && result [0] == "")
//        throw new CompletionResult ("", new string [] { "=" });

      var results = members.Where (l => (l.Kind & (MemberKind.Field | MemberKind.Property)) != 0).Select (l => l.Name).ToList ();
      if (partial_name != null) {
        var temp = new List<string> ();
        AppendResults (temp, partial_name, results);
        results = temp;
      }

      throw new CompletionResult (partial_name == null ? "" : partial_name, results.Distinct ().ToArray ());
    }

    protected override void CloneTo (CloneContext clonectx, Expression t)
    {
      // Nothing
    }
  }

  public class EmptyCompletion : CompletingExpression
  {
    protected override void CloneTo (CloneContext clonectx, Expression target)
    {
    }

    protected override Expression DoResolve (ResolveContext rc)
    {
      throw new CompletionResult ("", new string [0]);
    }
  }
  
}