2001-10-22 Ravi Pratap <ravi@ximian.com>

[mono.git] / mcs / mcs / rootcontext.cs

//
// rootcontext.cs: keeps track of our tree representation, and assemblies loaded.
//
// Author: Miguel de Icaza (miguel@ximian.com)
//
// Licensed under the terms of the GNU GPL
//
// (C) 2001 Ximian, Inc (http://www.ximian.com)

using System;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;
using System.Diagnostics;

namespace CIR {

        public class RootContext {

                //
                // Contains the parsed tree
                //
                Tree tree;

                //
                // Contains loaded assemblies and our generated code as we go.
                //
                public TypeManager TypeManager;

                //
                // The System.Reflection.Emit CodeGenerator
                //
                CodeGen cg;

                //
                // The module builder pointer
                //
                ModuleBuilder mb;

                //
                // Whether we are being linked against the standard libraries.
                // This is only used to tell whether `System.Object' should
                // have a parent or not.
                //
                bool stdlib = true;

                //
                // This keeps track of the order in which classes were defined
                // so that we can poulate them in that order.
                //
                // Order is important, because we need to be able to tell by
                // examining the parent's list of methods which ones are virtual
                // or abstract as well as the parent names (to implement new, 
                // override).
                //
                ArrayList type_container_resolve_order;
                ArrayList interface_resolve_order;
                
                public RootContext ()
                {
                        tree = new Tree (this);
                        TypeManager = new TypeManager ();
                }

                public Tree Tree {
                        get {
                                return tree;
                        }
                }

                public CodeGen CodeGen {
                        get {
                                return cg;
                        }

                        set {
                                //
                                // Temporary hack, we should probably
                                // intialize `cg' rather than depending on
                                // external initialization of it.
                                //
                                cg = value;
                                mb = cg.ModuleBuilder;
                        }
                }

                string MakeFQN (string nsn, string name)
                {
                        string prefix = (nsn == "" ? "" : nsn + ".");

                        return prefix + name;
                }
                       
                // <remarks>
                //   This function is used to resolve the hierarchy tree.
                //   It processes interfaces, structs and classes in that order.
                //
                //   It creates the TypeBuilder's as it processes the user defined
                //   types.  
                // </remarks>
                public void ResolveTree ()
                {
                        //
                        // Interfaces are processed first, as classes and
                        // structs might inherit from an object or implement
                        // a set of interfaces, we need to be able to tell
                        // them appart by just using the TypeManager.
                        //

                        TypeContainer root = Tree.Types;

                        ArrayList ifaces = root.Interfaces;
                        if (ifaces != null){
                                interface_resolve_order = new ArrayList ();
                                
                                foreach (Interface i in ifaces) {
                                        Type t = i.DefineInterface (mb);
                                        if (t != null)
                                                interface_resolve_order.Add (i);
                                }
                        }
                                                
                        type_container_resolve_order = new ArrayList ();
                        
                        foreach (TypeContainer tc in root.Types) {
                                Type t = tc.DefineType (mb);
                                if (t != null)
                                        type_container_resolve_order.Add (tc);
                        }

                        if (root.Delegates != null)
                                foreach (Delegate d in root.Delegates) 
                                        d.DefineDelegate (mb);
                        
                }
                        
                // <summary>
                //   Closes all open types
                // </summary>
                //
                // <remarks>
                //   We usually use TypeBuilder types.  When we are done
                //   creating the type (which will happen after we have added
                //   methods, fields, etc) we need to "Define" them before we
                //   can save the Assembly
                // </remarks>
                public void CloseTypes ()
                {
                        TypeContainer root = Tree.Types;
                        
                        ArrayList ifaces = root.Interfaces;

                        if (ifaces != null)
                                foreach (Interface i in ifaces) 
                                        i.CloseType ();
                        
                        foreach (TypeContainer tc in root.Types)
                                tc.CloseType ();

                        if (root.Delegates != null)
                                foreach (Delegate d in root.Delegates)
                                        d.CloseDelegate ();
                        
                }
                
                //
                // Public function used to locate types, this can only
                // be used after the ResolveTree function has been invoked.
                //
                // Returns: Type or null if they type can not be found.
                //
                public Type LookupType (TypeContainer tc, string name, bool silent)
                {
                        Type t;

                        t = TypeManager.LookupType (MakeFQN (tc.Namespace.Name, name));
                        if (t != null)
                                return t;

                        // It's possible that name already is fully qualified. So we do
                        // a simple direct lookup without adding any namespace names

                        t = TypeManager.LookupType (name); 
                        if (t != null)
                                return t;
                        
                        for (Namespace ns = tc.Namespace; ns != null; ns = ns.Parent){
                                ArrayList using_list = ns.UsingTable;

                                if (using_list == null)
                                        continue;

                                foreach (string n in using_list){
                                        t = TypeManager.LookupType (MakeFQN (n, name));
                                        if (t != null)
                                                return t;
                                }
                        }

                        // For the case the type we are looking for is nested within this one.
                        t = TypeManager.LookupType (tc.Name + "." + name);
                        if (t != null)
                                return t;
                        
                        if (!silent)
                                Report.Error (246, "Cannot find type `"+name+"'");
                        
                        return null;
                }

                // <summary>
                //   This is the silent version of LookupType, you can use this
                //   to `probe' for a type
                // </summary>
                public Type LookupType (TypeContainer tc, string name)
                {
                        return LookupType (tc, name, true);
                }

                public bool IsNamespace (string name)
                {
                        Namespace ns;

                        if (tree.Namespaces != null){
                                ns = (Namespace) tree.Namespaces [name];

                                if (ns != null)
                                        return true;
                        }

                        return false;
                }

                // <summary>
                //   Populates the structs and classes with fields and methods
                // </summary>
                //
                // This is invoked after all interfaces, structs and classes
                // have been defined through `ResolveTree' 
                public void PopulateTypes ()
                {
                        if (interface_resolve_order != null)
                                foreach (Interface iface in interface_resolve_order)
                                        iface.Populate ();

                        if (type_container_resolve_order != null)
                                foreach (TypeContainer tc in type_container_resolve_order)
                                        tc.Populate ();

                        ArrayList delegates = Tree.Types.Delegates;
                        if (delegates != null)
                                foreach (Delegate d in delegates)
                                        d.Populate (Tree.Types);
                       
                }

                public void EmitCode ()
                {
                        if (type_container_resolve_order != null)
                                foreach (TypeContainer tc in type_container_resolve_order)
                                        tc.Emit ();

                }
                
                // <summary>
                //   Compiling against Standard Libraries property.
                // </summary>
                public bool StdLib {
                        get {
                                return stdlib;
                        }

                        set {
                                stdlib = value;
                        }
                }

                //
                // Public Field, used to track which method is the public entry
                // point.
                //
                public MethodInfo EntryPoint;
        }
}