source: trunk/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Resolver/CSharpAstResolver.cs

// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
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// 
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// substantial portions of the Software.
// 
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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using System;
using System.Diagnostics;
using System.Threading;
using ICSharpCode.NRefactory.CSharp.TypeSystem;
using ICSharpCode.NRefactory.Semantics;
using ICSharpCode.NRefactory.TypeSystem;

namespace ICSharpCode.NRefactory.CSharp.Resolver
{
  /// <summary>
  /// Resolves C# AST nodes.
  /// </summary>
  /// <remarks>This class is thread-safe.</remarks>
  public class CSharpAstResolver
  {
    readonly CSharpResolver initialResolverState;
    readonly AstNode rootNode;
    readonly CSharpUnresolvedFile unresolvedFile;
    readonly ResolveVisitor resolveVisitor;
    bool resolverInitialized;
    
    /// <summary>
    /// Creates a new C# AST resolver.
    /// Use this overload if you are resolving within a complete C# file.
    /// </summary>
    /// <param name="compilation">The current compilation.</param>
    /// <param name="syntaxTree">The syntax tree to be resolved.</param>
    /// <param name="unresolvedFile">
    /// Optional: Result of <see cref="SyntaxTree.ToTypeSystem()"/> for the file being resolved.
    /// <para>
    /// This is used for setting up the context on the resolver. The unresolved file must be registered in the compilation.
    /// </para>
    /// <para>
    /// When a unresolvedFile is specified, the resolver will use the member's StartLocation/EndLocation to identify
    /// member declarations in the AST with members in the type system.
    /// When no unresolvedFile is specified (<c>null</c> value for this parameter), the resolver will instead compare the
    /// member's signature in the AST with the signature in the type system.
    /// </para>
    /// </param>
    public CSharpAstResolver(ICompilation compilation, SyntaxTree syntaxTree, CSharpUnresolvedFile unresolvedFile = null)
    {
      if (compilation == null)
        throw new ArgumentNullException("compilation");
      if (syntaxTree == null)
        throw new ArgumentNullException("syntaxTree");
      this.initialResolverState = new CSharpResolver(compilation);
      this.rootNode = syntaxTree;
      this.unresolvedFile = unresolvedFile;
      this.resolveVisitor = new ResolveVisitor(initialResolverState, unresolvedFile);
    }
    
    /// <summary>
    /// Creates a new C# AST resolver.
    /// Use this overload if you are resolving code snippets (not necessarily complete files).
    /// </summary>
    /// <param name="resolver">The resolver state at the root node (to be more precise: just outside the root node).</param>
    /// <param name="rootNode">The root node of the tree to be resolved.</param>
    /// <param name="unresolvedFile">
    /// Optional: Result of <see cref="SyntaxTree.ToTypeSystem()"/> for the file being resolved.
    /// <para>
    /// This is used for setting up the context on the resolver. The unresolved file must be registered in the compilation.
    /// </para>
    /// <para>
    /// When a unresolvedFile is specified, the resolver will use the member's StartLocation/EndLocation to identify
    /// member declarations in the AST with members in the type system.
    /// When no unresolvedFile is specified (<c>null</c> value for this parameter), the resolver will instead compare the
    /// member's signature in the AST with the signature in the type system.
    /// </para>
    /// </param>
    public CSharpAstResolver(CSharpResolver resolver, AstNode rootNode, CSharpUnresolvedFile unresolvedFile = null)
    {
      if (resolver == null)
        throw new ArgumentNullException("resolver");
      if (rootNode == null)
        throw new ArgumentNullException("rootNode");
      this.initialResolverState = resolver;
      this.rootNode = rootNode;
      this.unresolvedFile = unresolvedFile;
      this.resolveVisitor = new ResolveVisitor(initialResolverState, unresolvedFile);
    }
    
    /// <summary>
    /// Gets the type resolve context for the root resolver.
    /// </summary>
    public CSharpTypeResolveContext TypeResolveContext {
      get { return initialResolverState.CurrentTypeResolveContext; }
    }
    
    /// <summary>
    /// Gets the compilation for this resolver.
    /// </summary>
    public ICompilation Compilation {
      get { return initialResolverState.Compilation; }
    }
    
    /// <summary>
    /// Gets the root node for which this CSharpAstResolver was created.
    /// </summary>
    public AstNode RootNode {
      get { return rootNode; }
    }
    
    /// <summary>
    /// Gets the unresolved file used by this CSharpAstResolver.
    /// Can return null.
    /// </summary>
    public CSharpUnresolvedFile UnresolvedFile {
      get { return unresolvedFile; }
    }
    
    /// <summary>
    /// Applies a resolver navigator. This will resolve the nodes requested by the navigator, and will inform the
    /// navigator of the results.
    /// This method must be called as the first operation on the CSharpAstResolver, it is invalid to apply a navigator
    /// after a portion of the file was already resolved.
    /// </summary>
    public void ApplyNavigator(IResolveVisitorNavigator navigator, CancellationToken cancellationToken = default(CancellationToken))
    {
      if (navigator == null)
        throw new ArgumentNullException("navigator");
      
      lock (resolveVisitor) {
        if (resolverInitialized)
          throw new InvalidOperationException("Applying a navigator is only valid as the first operation on the CSharpAstResolver.");
        
        resolverInitialized = true;
        resolveVisitor.cancellationToken = cancellationToken;
        resolveVisitor.SetNavigator(navigator);
        try {
          resolveVisitor.Scan(rootNode);
        } finally {
          resolveVisitor.SetNavigator(null);
          resolveVisitor.cancellationToken = CancellationToken.None;
        }
      }
    }
    
    /// <summary>
    /// Resolves the specified node.
    /// </summary>
    public ResolveResult Resolve(AstNode node, CancellationToken cancellationToken = default(CancellationToken))
    {
      if (node == null || node.IsNull || IsUnresolvableNode(node))
        return ErrorResolveResult.UnknownError;
      lock (resolveVisitor) {
        InitResolver();
        resolveVisitor.cancellationToken = cancellationToken;
        try {
          ResolveResult rr = resolveVisitor.GetResolveResult(node);
          if (rr == null)
            Debug.Fail (node.GetType () + " resolved to null.", node.StartLocation + ":'" + node.ToString () + "'");
          return rr;
        } finally {
          resolveVisitor.cancellationToken = CancellationToken.None;
        }
      }
    }
    
    void InitResolver()
    {
      if (!resolverInitialized) {
        resolverInitialized = true;
        resolveVisitor.Scan(rootNode);
      }
    }
    
    /// <summary>
    /// Gets the resolver state immediately before the specified node.
    /// That is, if the node is a variable declaration, the returned state will not contain the newly declared variable.
    /// </summary>
    public CSharpResolver GetResolverStateBefore(AstNode node, CancellationToken cancellationToken = default(CancellationToken))
    {
      if (node == null || node.IsNull)
        throw new ArgumentNullException("node");
      lock (resolveVisitor) {
        InitResolver();
        resolveVisitor.cancellationToken = cancellationToken;
        try {
          CSharpResolver resolver = resolveVisitor.GetResolverStateBefore(node);
          Debug.Assert(resolver != null);
          return resolver;
        } finally {
          resolveVisitor.cancellationToken = CancellationToken.None;
        }
      }
    }
    
    /// <summary>
    /// Gets the resolver state immediately after the specified node.
    /// That is, if the node is a variable declaration, the returned state will include the newly declared variable.
    /// </summary>
    public CSharpResolver GetResolverStateAfter(AstNode node, CancellationToken cancellationToken = default(CancellationToken))
    {
      if (node == null || node.IsNull)
        throw new ArgumentNullException("node");
      while (node != null && IsUnresolvableNode(node))
        node = node.Parent;
      if (node == null)
        return initialResolverState;
      lock (resolveVisitor) {
        InitResolver();
        resolveVisitor.cancellationToken = cancellationToken;
        try {
          CSharpResolver resolver = resolveVisitor.GetResolverStateAfter(node);
          Debug.Assert(resolver != null);
          return resolver;
        } finally {
          resolveVisitor.cancellationToken = CancellationToken.None;
        }
      }
    }
    
    ResolveVisitor.ConversionWithTargetType GetConversionWithTargetType(Expression expr, CancellationToken cancellationToken)
    {
      if (expr == null || expr.IsNull)
        return new ResolveVisitor.ConversionWithTargetType(Conversion.None, SpecialType.UnknownType);
      lock (resolveVisitor) {
        InitResolver();
        resolveVisitor.cancellationToken = cancellationToken;
        try {
          return resolveVisitor.GetConversionWithTargetType(expr);
        } finally {
          resolveVisitor.cancellationToken = CancellationToken.None;
        }
      }
    }
    
    /// <summary>
    /// Gets the expected type for the specified node. This is the type that a node is being converted to.
    /// </summary>
    public IType GetExpectedType(Expression expr, CancellationToken cancellationToken = default(CancellationToken))
    {
      return GetConversionWithTargetType(expr, cancellationToken).TargetType;
    }
    
    /// <summary>
    /// Gets the conversion that is being applied to the specified expression.
    /// </summary>
    public Conversion GetConversion(Expression expr, CancellationToken cancellationToken = default(CancellationToken))
    {
      return GetConversionWithTargetType(expr, cancellationToken).Conversion;
    }
    
    /// <summary>
    /// Gets whether the specified node is unresolvable.
    /// </summary>
    public static bool IsUnresolvableNode(AstNode node)
    {
      if (node == null)
        throw new ArgumentNullException("node");
      if (node.NodeType == NodeType.Token) {
        // Most tokens cannot be resolved, but there are a couple of special cases:
        if (node.Parent is QueryClause && node is Identifier) {
          return false;
        } else if (node.Role == Roles.Identifier) {
          return !(node.Parent is ForeachStatement || node.Parent is CatchClause);
        }
        return true;
      }
      return (node.NodeType == NodeType.Whitespace || node is ArraySpecifier);
    }
  }
}