/src/Boo.Lang.Compiler/TypeSystem/NameResolutionService.cs

#region license

// Copyright (c) 2004, Rodrigo B. de Oliveira (rbo@acm.org)

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without modification,

// are permitted provided that the following conditions are met:

// 

//     * Redistributions of source code must retain the above copyright notice,

//     this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright notice,

//     this list of conditions and the following disclaimer in the documentation

//     and/or other materials provided with the distribution.

//     * Neither the name of Rodrigo B. de Oliveira nor the names of its

//     contributors may be used to endorse or promote products derived from this

//     software without specific prior written permission.

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE

// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#endregion



namespace Boo.Lang.Compiler.TypeSystem

{

	using System;

	using System.Collections;

	using Boo.Lang.Compiler.Ast;

	using System.Reflection;

	using System.Collections.Generic;

	

	public class NameResolutionService

	{

		public static readonly char[] DotArray = new char[] { '.' };

		

		protected CompilerContext _context;

		

		protected INamespace _current;

		

		protected INamespace _global = NullNamespace.Default;

		

		protected List _buffer = new List();

		

		protected List _innerBuffer = new List();

		

		public NameResolutionService(CompilerContext context)

		{

			if (null == context) throw new ArgumentNullException("context");

			_context = context;

		}

		

		public INamespace GlobalNamespace

		{

			get { return _global; }

			

			set

			{

				if (null == value)

				{

					throw new ArgumentNullException("GlobalNamespace");

				}

				_global = value;

			}

		}		

		

		public void EnterNamespace(INamespace ns)

		{

			if (null == ns) throw new ArgumentNullException("ns");

			_current = ns;

		}

		

		public INamespace CurrentNamespace

		{

			get { return _current; }

			}

		

		public void Reset()

		{

			EnterNamespace(_global);

		}

		

		public void Restore(INamespace saved)

		{

			if (null == saved) throw new ArgumentNullException("saved");

			_current = saved;

		}

		

		public void LeaveNamespace()

		{

			_current = _current.ParentNamespace;

		}

		

		public IEntity Resolve(string name)

		{

			return Resolve(name, EntityType.Any);

		}

		

		public IEntity Resolve(string name, EntityType flags)

		{			

			_buffer.Clear();

			Resolve(_buffer, name, flags);

			return GetEntityFromBuffer();

		}

		

		public bool Resolve(List targetList, string name)

		{

			return Resolve(targetList, name, EntityType.Any);

		}

		

		public bool Resolve(List targetList, string name, EntityType flags)

		{
			IEntity entity = _context.TypeSystemServices.ResolvePrimitive(name);

			if (null != entity)

			{

				targetList.Add(entity);

				return true;

			}



			INamespace ns = _current;

			while (null != ns)

			{
				if (ns.Resolve(targetList, name, flags))

				{

					return true;

				}

				ns = ns.ParentNamespace;

			}

			return false;

		}



		public IEntity ResolveExtension(INamespace ns, string name)

		{

			IType type = ns as IType;

			if (null == type) return null;

			

			INamespace current = _current;

			while (null != current)

			{

				IEntity found = ResolveExtensionForType(current, type, name);

				if (null != found) return found;

				current = current.ParentNamespace;

			}

			return null;

		}



		class IsNotExtensionOf

		{

			private IType _type;



			public IsNotExtensionOf(IType type)

			{

				_type = type;

			}



			public bool Match(object item)

			{

				IExtensionEnabled e = item as IExtensionEnabled;

				if (e == null) return true;

				if (!e.IsExtension) return true;

				IParameter[] parameters = e.GetParameters();

				if (parameters.Length == 0) return true;

				return !parameters[0].Type.IsAssignableFrom(_type);

			}

		}



		private IEntity ResolveExtensionForType(INamespace ns, IType type, string name)

		{

			_buffer.Clear();

			if (!ns.Resolve(_buffer, name, EntityType.Method|EntityType.Property)) return null;

			_buffer.RemoveAll(new IsNotExtensionOf(type).Match);

			return GetEntityFromBuffer();

		}

		

		public IEntity ResolveQualifiedName(string name)

		{
			_buffer.Clear();

			ResolveQualifiedName(_buffer, name);

			return GetEntityFromBuffer();

		}

		

		public bool ResolveQualifiedName(List targetList, string name)

		{
			return ResolveQualifiedName(targetList, name, EntityType.Any);

		}

		

		public bool ResolveQualifiedName(List targetList, string name, EntityType flags)

		{
			if (!IsQualifiedName(name))

			{
				return Resolve(targetList, name, flags);

			}

			

			string[] parts = name.Split(DotArray);

			string topLevel = parts[0];

			

			_innerBuffer.Clear();

			if (Resolve(_innerBuffer, topLevel) && 1 == _innerBuffer.Count)

			{

				INamespace ns = _innerBuffer[0] as INamespace;

				if (null != ns)

				{

					int last = parts.Length-1;

					for (int i=1; i<last; ++i)				

					{	

						_innerBuffer.Clear();

						if (!ns.Resolve(_innerBuffer, parts[i], EntityType.Any) ||

							1 != _innerBuffer.Count)

						{

							return false;

						}				

						ns = _innerBuffer[0] as INamespace;

						if (null == ns)

						{

							return false;

						}

					}

					return ns.Resolve(targetList, parts[last], flags);
				}

			}

			return false;

		}


		public void ResolveTypeReference(TypeReference node)

		{
			if (null != node.Entity) return;

			switch (node.NodeType)
			{
				case NodeType.ArrayTypeReference:
					ResolveArrayTypeReference((ArrayTypeReference) node);
					break;

				case NodeType.CallableTypeReference:
					//not needed? (late resolution)
					//ResolveCallableTypeReference((CallableTypeReference) node);
					break;

				default:
					ResolveSimpleTypeReference((SimpleTypeReference) node);
					break;
			}

		}


		public void ResolveArrayTypeReference(ArrayTypeReference node)

		{

			if (null != node.Entity) return;


			ResolveTypeReference(node.ElementType);

			

			IType elementType = TypeSystemServices.GetType(node.ElementType);

			if (TypeSystemServices.IsError(elementType))

			{

				node.Entity = TypeSystemServices.ErrorEntity;

			}

			else

			{

				int rank = null == node.Rank ? 1 : (int)node.Rank.Value;

				node.Entity = _context.TypeSystemServices.GetArrayType(elementType, rank);

			}

		}


		private void ResolveTypeReferenceCollection(TypeReferenceCollection collection)

		{

			foreach (TypeReference tr in collection)

			{

				ResolveTypeReference(tr);

			}

		}

		

		public void ResolveSimpleTypeReference(SimpleTypeReference node)

		{

			if (null != node.Entity) return;

			

			IEntity entity = ResolveTypeName(node);

			if (null == entity)

			{

				node.Entity = NameNotType(node);

				return;

			}

			if (EntityType.Type != entity.EntityType)

			{

				if (EntityType.Ambiguous == entity.EntityType)

				{

					entity = AmbiguousReference(node, (Ambiguous)entity);

				}

				else

				{

					entity = NameNotType(node);

				}

			}

			else

			{

				GenericTypeReference gtr = node as GenericTypeReference;

				if (null != gtr)

				{

					ResolveTypeReferenceCollection(gtr.GenericArguments);

					entity = ResolveGenericTypeReference(gtr, entity);

				}

				

				GenericTypeDefinitionReference gtdr = node as GenericTypeDefinitionReference;

				if (null != gtdr)

				{

					IType type = (IType)entity;

					if (gtdr.GenericPlaceholders != type.GenericInfo.GenericParameters.Length)

					{

						entity = GenericArgumentsCountMismatch(gtdr, type);

					}

				}



				node.Name = entity.FullName;

			}

			

			node.Entity = entity;		

		}



		private IEntity ResolveTypeName(SimpleTypeReference node)

		{	

			_buffer.Clear();

			if (IsQualifiedName(node.Name))

			{

				ResolveQualifiedName(_buffer, node.Name);

			}

			else

			{

				Resolve(_buffer, node.Name, EntityType.Type);

			}





			// Remove from the buffer types that do not match requested generity

			FilterGenericTypes(_buffer, node);

			return GetEntityFromBuffer();

		}



		public IType ResolveGenericTypeReference(GenericTypeReference gtr, IEntity definition)

		{

			ResolveTypeReferenceCollection(gtr.GenericArguments);

			IType[] typeArguments = GetTypes(gtr.GenericArguments);

			

			return (IType)_context.TypeSystemServices.GenericsServices.ConstructEntity(

				gtr, definition, typeArguments);

		}



		public IEntity ResolveGenericReferenceExpression(GenericReferenceExpression gre, IEntity definition)

		{

			ResolveTypeReferenceCollection(gre.GenericArguments);

			IType[] typeArguments = GetTypes(gre.GenericArguments);

			

			return _context.TypeSystemServices.GenericsServices.ConstructEntity(

				gre, definition, typeArguments);

		}



		private IType[] GetTypes(TypeReferenceCollection typeReferences)

		{

			return Array.ConvertAll<TypeReference, IType>(

				typeReferences.ToArray(),

				TypeSystemServices.GetType);

		}



		private void FilterGenericTypes(List types, SimpleTypeReference node)		

		{			

			bool genericRequested = (node is GenericTypeReference || node is GenericTypeDefinitionReference);

			

			for (int i = 0; i < types.Count; i++)

			{

				IType type = types[i] as IType;

				if (type == null) continue;

				

				// Remove type from list of matches if it doesn't match requested generity

				if (type.GenericInfo != null ^ genericRequested)

				{

					types.RemoveAt(i);

					i--;

				}

			}

		}



		private IEntity NameNotType(SimpleTypeReference node)

		{
			string suggestion = GetMostSimilarTypeName(node.Name);

			_context.Errors.Add(CompilerErrorFactory.NameNotType(node, node.ToCodeString(), suggestion));

			return TypeSystemServices.ErrorEntity;

		}



		private IEntity AmbiguousReference(SimpleTypeReference node, Ambiguous entity)

		{

			_context.Errors.Add(CompilerErrorFactory.AmbiguousReference(node, node.Name, entity.Entities));

			return TypeSystemServices.ErrorEntity;

		}

		

		private IEntity GenericArgumentsCountMismatch(TypeReference node, IType type)

		{

			_context.Errors.Add(CompilerErrorFactory.GenericDefinitionArgumentCount(node, type.FullName, type.GenericInfo.GenericParameters.Length));

			return TypeSystemServices.ErrorEntity; 

		}

		

		public static IField ResolveField(IType type, string name)

		{

			return (IField)ResolveMember(type, name, EntityType.Field);

		}

		

		public static IMethod ResolveMethod(IType type, string name)

		{
			return (IMethod)ResolveMember(type, name, EntityType.Method);

		}

		

		public static IProperty ResolveProperty(IType type, string name)

		{

			return (IProperty)ResolveMember(type, name, EntityType.Property);

		}

		

		public static IEntity ResolveMember(IType type, string name, EntityType elementType)

		{
			foreach (IEntity member in type.GetMembers())

			{				

				if (elementType == member.EntityType && name == member.Name)

				{

					return member;

				}

			}

			return null;

		}

		

		public IEntity Resolve(INamespace ns, string name, EntityType elementType)

		{

			_buffer.Clear();

			ns.Resolve(_buffer, name, elementType);

			return GetEntityFromList(_buffer);

		}

		

		public IEntity Resolve(INamespace ns, string name)

		{

			return Resolve(ns, name, EntityType.Any);

		}


		IEntity GetEntityFromBuffer()

		{

			return GetEntityFromList(_buffer);

		}

		

		public static IEntity GetEntityFromList(IList list)

		{

			IEntity element = null;

			if (list.Count > 0)

			{

				if (list.Count > 1)

				{

					element = new Ambiguous(list);

				}

				else

				{

					element = (IEntity)list[0];

				}

				list.Clear();

			}

			return element;

		}

		

		static bool IsQualifiedName(string name)

		{

			return name.IndexOf('.') > 0;

		}	

		

		public static bool IsFlagSet(EntityType flags, EntityType flag)

		{

			return flag == (flags & flag);

		}

		

		public void OrganizeAssemblyTypes(Assembly asm)

		{

			CatalogPublicTypes(asm.GetTypes());

		}



		private void CatalogPublicTypes(Type[] types)

		{
			string lastNs = "!!not a namespace!!";
			NamespaceEntity lastNsEntity = null;


			foreach (Type type in types)

			{
				if (!type.IsPublic) continue;

				string ns = type.Namespace ?? string.Empty;
				//retrieve the namespace only if we don't have it handy already
				//usually we'll have it since GetExportedTypes() seems to export
				//types in a sorted fashion.
				if (ns != lastNs)
				{
					lastNs = ns;

					lastNsEntity = GetNamespace(ns);
					lastNsEntity.Add(type);
				}
				else
				{
					lastNsEntity.Add(type);
				}

			}

		}


		public NamespaceEntity GetNamespace(string ns)

		{

			string[] namespaceHierarchy = ns.Split('.');

			string topLevelName = namespaceHierarchy[0];

			NamespaceEntity topLevel = GetTopLevelNamespace(topLevelName);

			NamespaceEntity current = topLevel;

			for (int i=1; i<namespaceHierarchy.Length; ++i)

			{

				current = current.GetChildNamespace(namespaceHierarchy[i]);

			}

			return current;

		}

		

		NamespaceEntity GetTopLevelNamespace(string topLevelName)

		{

			GlobalNamespace globalNS = GetGlobalNamespace();

			if (globalNS == null) return null;

			

			NamespaceEntity entity = (NamespaceEntity)globalNS.GetChild(topLevelName);

			if (null == entity)

			{

				entity = new NamespaceEntity(null, _context.TypeSystemServices, topLevelName);

				globalNS.SetChild(topLevelName, entity);

			}

			return entity;

		}

		

		GlobalNamespace GetGlobalNamespace()

		{

			INamespace ns = _global;

			GlobalNamespace globals = ns as GlobalNamespace;

			while (globals == null && ns != null)

			{

				ns = ns.ParentNamespace;

				globals = ns as GlobalNamespace;

			}

			return globals;

		}


		private static void FlattenChildNamespaces(List<INamespace> list, INamespace ns)
		{
			foreach (IEntity ent in ns.GetMembers())
			{
				if (EntityType.Namespace != ent.EntityType) continue;
				list.Add((INamespace) ent);
				FlattenChildNamespaces(list, (INamespace) ent);
			}
		}

		public string GetMostSimilarTypeName(string name)
		{
			string[] nsHierarchy = name.Split('.');
			int nshLen = nsHierarchy.Length;
			string suggestion = null;

			if (nshLen > 1)
			{
				INamespace ns = null;
				INamespace prevNs = null;
				for (int i = 1; i < nshLen; i++)
				{
					string currentNsName = string.Join(".", nsHierarchy, 0, i);
					ns = ResolveQualifiedName(currentNsName) as INamespace;
					if (null == ns)
					{
						nsHierarchy[i-1] = GetMostSimilarMemberName(prevNs, nsHierarchy[i-1], EntityType.Namespace);
						if (null == nsHierarchy[i-1]) break;
						i--; continue; //reloop to resolve step
					}
					prevNs = ns;
				}
				suggestion = GetMostSimilarMemberName(ns, nsHierarchy[nshLen-1], EntityType.Type);
				if (null != suggestion)
				{
					nsHierarchy[nshLen-1] = suggestion;
					return string.Join(".", nsHierarchy);
				}
			}
		
			List<INamespace> nsList = new List<INamespace>();
			FlattenChildNamespaces(nsList, GetGlobalNamespace());
			nsList.Reverse();//most recently added namespaces first
			foreach (INamespace nse in nsList)
			{
				suggestion = GetMostSimilarMemberName(nse, nsHierarchy[nshLen-1], EntityType.Type);
				if (null != suggestion) return nse.ToString()+"."+suggestion;
			}
			return GetMostSimilarMemberName(GetGlobalNamespace(), nsHierarchy[nshLen-1], EntityType.Type);
		}

		public string GetMostSimilarMemberName(INamespace ns, string name, EntityType elementType)
		{
			if (null == ns) return null;

			string expectedSoundex = ToSoundex(name);
			string lastMemberName = null;
			foreach (IEntity member in ns.GetMembers())

			{
				if (EntityType.Any != elementType && elementType != member.EntityType)
					continue;
				if (lastMemberName == member.Name)
					continue;//no need to check this name again
				//TODO: try Levenshtein distance or Metaphone instead of Soundex.
				if (expectedSoundex == ToSoundex(member.Name))

				{

					return member.Name;

				}
				lastMemberName = member.Name;

			}
			return null;
		}

		private static string ToSoundex(string s)
		{
			if (s.Length < 2) return null;
			char[] code = "?0000".ToCharArray();
			string ws = s.ToLowerInvariant();
			int wsLen = ws.Length;
			char lastChar = ' ';
			int lastCharPos = 1;

			code[0] = ws[0];
			for (int i = 1; i < wsLen; i++)
			{
				char wsc = ws[i];
				char c = ' ';
				if (wsc == 'b' || wsc == 'f' || wsc == 'p' || wsc == 'v') c = '1';
				if (wsc == 'c' || wsc == 'g' || wsc == 'j' || wsc == 'k' || wsc == 'q' || wsc == 's' || wsc == 'x' || wsc == 'z') c = '2';
				if (wsc == 'd' || wsc == 't') c = '3';
				if (wsc == 'l') c = '4';
				if (wsc == 'm' || wsc == 'n') c = '5';
				if (wsc == 'r') c = '6';
				if (c == lastChar) continue;
				lastChar = c;
				if (c == ' ') continue;
				code[lastCharPos] = c;
				lastCharPos++;
				if (lastCharPos > 4) break;
			}
			return new string(code);
        }


	}

}