/*

* Copyright (c) 2004-2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

using SymbianUtils;

using SymbianUtils.Range;

using SymbianUtils.Tracer;

using SymbianUtils.FileTypes;

using SymbianStructuresLib.Debug.Code;

using SymbianStructuresLib.CodeSegments;

using SymbianCodeLib.DbgEnginePlugin;

using SymbianCodeLib.SourceManagement.Source;

using SymbianCodeLib.QueryAPI;

namespace SymbianCodeLib.Relocator

{

    internal class CodeRelocator : DisposableObject, IEnumerable<CodeSourceAndCollection>

    {

        #region Constructors

        public CodeRelocator( CodePlugin aPlugin )

		{

            iPlugin = aPlugin;

		}

		#endregion

        #region API

        public CodeCollection Activate( CodeSegDefinition aCodeSegment )

        {

            CodeCollection ret = null;

            // Find the corresponding Code seg

            CodeSourceAndCollection pair = SourceManager[ aCodeSegment ];

            if ( pair != null  )

            {

                CodeCollection col = pair.Collection;

                if ( col.IsFixed )

                {

                    // Cannot activate a fixed Code segment - TODO: should this return "true", i.e. already activated?

                }

                else

                {

                    bool safe = CheckSafeToActivate( aCodeSegment );

                    if ( safe )

                    {

                        // Deep copy the collection

                        CodeCollection dupe = CodeCollection.NewCopy( iPlugin.ProvisioningManager.IdAllocator, col );

                        // Set new process-specific relocated base address. This causes the underlying code to be

                        // decompressed/read if not already done so.

                        dupe.Relocate( aCodeSegment.Base );

                        // At this point, the code owned by 'col' will have definitely been read (if available)

                        // and that means col.IsCodeAvailable is probably true. However, dupe.IsCodeAvailable

                        // is almost certainly false so we may need to copy the code over...

                        if ( dupe.IsCodeAvailable == false && col.IsCodeAvailable == true )

                        {

                            dupe.Code = col.Code;

                        }

                        System.Diagnostics.Debug.Assert( dupe.IsCodeAvailable == col.IsCodeAvailable );

                        // Save so that we can unload it later

                        pair = new CodeSourceAndCollection( pair, dupe );

                        AddToActivationList( pair, aCodeSegment );

                        // We managed to activate a binary, so return the collection

                        ret = dupe;

                        iPlugin.Trace( "[C] ACTIVATE - {0}", aCodeSegment );

                    }

                }

            }

            //

            return ret;

        }

        public bool Deactivate( CodeSegDefinition aCodeSegment )

        {

            bool activated = iActivationLUT.ContainsKey( aCodeSegment );

            //

            if ( activated )

            {

                CodeSourceAndCollection pair = iActivationLUT[ aCodeSegment ];

                //

                iActivatedCollections.Remove( pair.Collection );

                iActivationLUT.Remove( aCodeSegment );

                //

                iPlugin.Trace( "[C] DEACTIVATE - {0} @ {1}", pair.Collection.FileName, aCodeSegment );

            }

            //

            return activated;

        }

        #endregion

		#region Properties

        public CodeCollectionList CollectionList

        {

            get { return iActivatedCollections; }

        }

        public int Count

        {

            get

            {

                System.Diagnostics.Debug.Assert( iActivatedCollections.Count == iActivationLUT.Count );

                return iActivationLUT.Count;

            }

        }

        #endregion

        #region Internal methods

        internal CodePlugin Plugin

        {

            get { return iPlugin; }

        }

        internal CodeSourceManager SourceManager

        {

            get { return Plugin.SourceManager; }

        }

        private void AddToActivationList( CodeSourceAndCollection aEntry, CodeSegDefinition aCodeSegment )

        {

            lock ( iActivatedCollections )

            {

                iActivatedCollections.Add( aEntry.Collection );

            }

            lock ( iActivationLUT )

            {

                iActivationLUT.Add( aCodeSegment, aEntry );

            }

        }

        private bool CheckSafeToActivate( CodeSegDefinition aCodeSegment )

        {

            lock ( iActivationLUT )

            {

                bool alreadyExists = iActivationLUT.ContainsKey( aCodeSegment );

                if ( alreadyExists )

                {

                    // Specified Code segment already activated

                    return false;

                }

                else

                {

                    // We must check that there's no overlap in activation ranges between Code segments.

                    foreach ( KeyValuePair<CodeSegDefinition, CodeSourceAndCollection> kvp in iActivationLUT )

                    {

                        AddressRange range = kvp.Key;

                        if ( range.Contains( aCodeSegment ) )

                        {

                            // Overlaps with existing activated Code segment

                            return false;

                        }

                    }

                }

                //

                return true;

            }

        }

        #endregion

        #region From IEnumerable<CodeSourceAndCollection>

        public IEnumerator<CodeSourceAndCollection> GetEnumerator()

        {

            foreach ( KeyValuePair<CodeSegDefinition, CodeSourceAndCollection> kvp in iActivationLUT )

            {

                yield return kvp.Value;

            }

        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()

        {

            foreach ( KeyValuePair<CodeSegDefinition, CodeSourceAndCollection> kvp in iActivationLUT )

            {

                yield return kvp.Value;

            }

        }

        #endregion

        #region From DisposableObject

        protected override void CleanupManagedResources()

        {

            try

            {

                base.CleanupManagedResources();

            }

            finally

            {

                foreach ( CodeCollection col in iActivatedCollections )

                {

                    // Fixed collections are immediately discarded

                    if ( !col.IsFixed )

                    {

                        col.Dispose();

                    }

                }

                iActivatedCollections.Clear();

                iActivationLUT.Clear();

            }

        }

        #endregion

        #region Data members

        private readonly CodePlugin iPlugin;

        private CodeCollectionList iActivatedCollections = new CodeCollectionList();

        private Dictionary<CodeSegDefinition, CodeSourceAndCollection> iActivationLUT = new Dictionary<CodeSegDefinition, CodeSourceAndCollection>();

        #endregion

    }

}