{
    This file is part of the Free Pascal Run Time Library (rtl)
    Copyright (c) 2007 by Michael Van Canneyt,
    member of the Free Pascal development team

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 **********************************************************************}

type
  // Quadruple representing an unresolved component property.

  { TUnresolvedReference }

  TUnresolvedReference = class(TlinkedListItem)
  Private
    FRoot: TComponent;     // Root component when streaming
    FPropInfo: PPropInfo;  // Property to set.
    FGlobal,               // Global component.
    FRelative : string;    // Path relative to global component.
    Function Resolve(Instance : TPersistent) : Boolean; // Resolve this reference
    Function RootMatches(ARoot : TComponent) : Boolean; {$ifdef CLASSESINLINE} inline; {$endif CLASSESINLINE} // True if Froot matches or ARoot is nil.
    Function NextRef : TUnresolvedReference; {$ifdef CLASSESINLINE} inline; {$endif CLASSESINLINE}
  end;
  
  TLocalUnResolvedReference = class(TUnresolvedReference)
    Finstance : TPersistent;
  end;

  // Linked list of TPersistent items that have unresolved properties.  

  { TUnResolvedInstance }

  TUnResolvedInstance = Class(TLinkedListItem)
    Instance : TPersistent; // Instance we're handling unresolveds for
    FUnresolved : TLinkedList; // The list
    Destructor Destroy; override;
    Function AddReference(ARoot : TComponent; APropInfo : PPropInfo; AGlobal,ARelative : String) : TUnresolvedReference;
    Function RootUnresolved : TUnresolvedReference; {$ifdef CLASSESINLINE} inline; {$endif CLASSESINLINE} // Return root element in list.
    Function ResolveReferences : Boolean; // Return true if all unresolveds were resolved.
  end;

  // Builds a list of TUnResolvedInstances, removes them from global list on free.
  TBuildListVisitor = Class(TLinkedListVisitor)
    List : TFPList;
    Procedure Add(Item : TlinkedListItem); // Add TUnResolvedInstance item to list. Create list if needed
    Destructor Destroy; override; // All elements in list (if any) are removed from the global list.
  end;
  
  // Visitor used to try and resolve instances in the global list
  TResolveReferenceVisitor = Class(TBuildListVisitor)
    Function Visit(Item : TLinkedListItem) : Boolean; override;
  end;
  
  // Visitor used to remove all references to a certain component.
  TRemoveReferenceVisitor = Class(TBuildListVisitor)
    FRef : String;
    FRoot : TComponent;
    Constructor Create(ARoot : TComponent;Const ARef : String);
    Function Visit(Item : TLinkedListItem) : Boolean; override;
  end;

  // Visitor used to collect reference names.
  TReferenceNamesVisitor = Class(TLinkedListVisitor)
    FList : TStrings;
    FRoot : TComponent;
    Function Visit(Item : TLinkedListItem) : Boolean; override;
    Constructor Create(ARoot : TComponent;AList : TStrings);
  end;

  // Visitor used to collect instance names.  
  TReferenceInstancesVisitor = Class(TLinkedListVisitor)
    FList : TStrings;
    FRef  : String;
    FRoot : TComponent;
    Function Visit(Item : TLinkedListItem) : Boolean; override;
    Constructor Create(ARoot : TComponent;Const ARef : String; AList : TStrings);
  end;
  
  // Visitor used to redirect links to another root component.
  TRedirectReferenceVisitor = Class(TLinkedListVisitor)
    FOld,
    FNew : String;
    FRoot : TComponent;
    Function Visit(Item : TLinkedListItem) : Boolean; override;
    Constructor Create(ARoot : TComponent;Const AOld,ANew : String);
  end;
  
var
  NeedResolving : TLinkedList;
  ResolveSection : TRTLCriticalSection;

// Add an instance to the global list of instances which need resolving.
Function FindUnresolvedInstance(AInstance: TPersistent) : TUnResolvedInstance;

begin
  Result:=Nil;
  EnterCriticalSection(ResolveSection);
  Try
    If Assigned(NeedResolving) then
      begin
      Result:=TUnResolvedInstance(NeedResolving.Root);
      While (Result<>Nil) and (Result.Instance<>AInstance) do
        Result:=TUnResolvedInstance(Result.Next);
      end;
  finally
    LeaveCriticalSection(ResolveSection);
  end;
end;

Function AddtoResolveList(AInstance: TPersistent) : TUnResolvedInstance;

begin
  Result:=FindUnresolvedInstance(AInstance);
  If (Result=Nil) then
    begin
    EnterCriticalSection(ResolveSection);
    Try
      If not Assigned(NeedResolving) then
        NeedResolving:=TLinkedList.Create(TUnResolvedInstance);
      Result:=NeedResolving.Add as TUnResolvedInstance;
      Result.Instance:=AInstance;
    finally
      LeaveCriticalSection(ResolveSection);
    end;
    end;
end;

// Walk through the global list of instances to be resolved.  

Procedure VisitResolveList(V : TLinkedListVisitor);

begin
  EnterCriticalSection(ResolveSection);
  Try
    try
      NeedResolving.Foreach(V);
    Finally
      FreeAndNil(V);
    end;  
  Finally
    LeaveCriticalSection(ResolveSection);
  end;  
end;

procedure GlobalFixupReferences;

begin
  If (NeedResolving=Nil) then 
    Exit;
  GlobalNameSpace.BeginWrite;
  try
    VisitResolveList(TResolveReferenceVisitor.Create);
  finally
    GlobalNameSpace.EndWrite;
  end;
end;


procedure GetFixupReferenceNames(Root: TComponent; Names: TStrings);

begin
  If (NeedResolving=Nil) then 
    Exit;
  VisitResolveList(TReferenceNamesVisitor.Create(Root,Names));
end;

procedure GetFixupInstanceNames(Root: TComponent; const ReferenceRootName: string; Names: TStrings);

begin
  If (NeedResolving=Nil) then
    Exit;
  VisitResolveList(TReferenceInstancesVisitor.Create(Root,ReferenceRootName,Names));
end;

procedure RedirectFixupReferences(Root: TComponent; const OldRootName, NewRootName: string);

begin
  If (NeedResolving=Nil) then
      Exit;
  VisitResolveList(TRedirectReferenceVisitor.Create(Root,OldRootName,NewRootName));
end;

procedure RemoveFixupReferences(Root: TComponent; const RootName: string);

begin
  If (NeedResolving=Nil) then
      Exit;
  VisitResolveList(TRemoveReferenceVisitor.Create(Root,RootName));
end;

procedure RemoveFixups(Instance: TPersistent);

begin
  // This needs work.
{
  if not Assigned(GlobalFixupList) then
    exit;

  with GlobalFixupList.LockList do
    try
      for i := Count - 1 downto 0 do
      begin
        CurFixup := TPropFixup(Items[i]);
        if (CurFixup.FInstance = Instance) then
        begin
          Delete(i);
          CurFixup.Free;
        end;
      end;
    finally
      GlobalFixupList.UnlockList;
    end;
}
end;

{ TUnresolvedReference }

Function TUnresolvedReference.Resolve(Instance : TPersistent) : Boolean;

Var
  C : TComponent;

begin
  C:=FindGlobalComponent(FGlobal);
  Result:=(C<>Nil);
  If Result then
    begin
    C:=FindNestedComponent(C,FRelative);
    Result:=C<>Nil;
    If Result then
      SetObjectProp(Instance, FPropInfo,C);
    end;
end; 

Function TUnresolvedReference.RootMatches(ARoot : TComponent) : Boolean; {$ifdef CLASSESINLINE} inline; {$endif CLASSESINLINE}

begin
  Result:=(ARoot=Nil) or (ARoot=FRoot);
end;

Function TUnResolvedReference.NextRef : TUnresolvedReference;

begin
  Result:=TUnresolvedReference(Next);
end;

{ TUnResolvedInstance }

destructor TUnResolvedInstance.Destroy;
begin
  FUnresolved.Free;
  inherited Destroy;
end;

function TUnResolvedInstance.AddReference(ARoot: TComponent;
  APropInfo: PPropInfo; AGlobal, ARelative: String): TUnresolvedReference;
begin
  If (FUnResolved=Nil) then
    FUnResolved:=TLinkedList.Create(TUnresolvedReference);
  Result:=FUnResolved.Add as TUnresolvedReference;
  Result.FGlobal:=AGLobal;
  Result.FRelative:=ARelative;
  Result.FPropInfo:=APropInfo;
  Result.FRoot:=ARoot;
end;

Function TUnResolvedInstance.RootUnresolved : TUnresolvedReference; 

begin
  Result:=Nil;
  If Assigned(FUnResolved) then
    Result:=TUnresolvedReference(FUnResolved.Root);
end;

Function TUnResolvedInstance.ResolveReferences:Boolean;

Var
  R,RN : TUnresolvedReference;

begin
  R:=RootUnResolved;
  While (R<>Nil) do
    begin
    RN:=R.NextRef;
    If R.Resolve(Self.Instance) then
      FUnresolved.RemoveItem(R,True);
    R:=RN;
    end;
  Result:=RootUnResolved=Nil;
end;

{ TReferenceNamesVisitor }

Constructor TReferenceNamesVisitor.Create(ARoot : TComponent;AList : TStrings);

begin
  FRoot:=ARoot;
  FList:=AList;
end;

Function TReferenceNamesVisitor.Visit(Item : TLinkedListItem) : Boolean;

Var
  R : TUnresolvedReference;

begin
  R:=TUnResolvedInstance(Item).RootUnresolved;
  While (R<>Nil) do
    begin
    If R.RootMatches(FRoot) then
      If (FList.IndexOf(R.FGlobal)=-1) then 
        FList.Add(R.FGlobal);
    R:=R.NextRef;
    end;
  Result:=True;
end;

{ TReferenceInstancesVisitor }

Constructor TReferenceInstancesVisitor.Create(ARoot : TComponent; Const ARef : String;AList : TStrings);

begin
  FRoot:=ARoot;
  FRef:=UpperCase(ARef);
  FList:=AList;
end;

Function TReferenceInstancesVisitor.Visit(Item : TLinkedListItem) : Boolean;

Var
  R : TUnresolvedReference;

begin
  R:=TUnResolvedInstance(Item).RootUnresolved;
  While (R<>Nil) do
    begin
    If (FRoot=R.FRoot) and (FRef=UpperCase(R.FGLobal)) Then
      If Flist.IndexOf(R.FRelative)=-1 then
        Flist.Add(R.FRelative);
    R:=R.NextRef;
    end;
  Result:=True;
end;

{ TRedirectReferenceVisitor }

Constructor TRedirectReferenceVisitor.Create(ARoot : TComponent; Const AOld,ANew  : String);

begin
  FRoot:=ARoot;
  FOld:=UpperCase(AOld);
  FNew:=ANew;
end;

Function TRedirectReferenceVisitor.Visit(Item : TLinkedListItem) : Boolean;

Var
  R : TUnresolvedReference;

begin
  R:=TUnResolvedInstance(Item).RootUnresolved;
  While (R<>Nil) do
    begin
    If R.RootMatches(FRoot) and (FOld=UpperCase(R.FGLobal)) Then
      R.FGlobal:=FNew;
    R:=R.NextRef;
    end;
  Result:=True;
end;

{ TRemoveReferenceVisitor }

Constructor TRemoveReferenceVisitor.Create(ARoot : TComponent; Const ARef  : String);

begin
  FRoot:=ARoot;
  FRef:=UpperCase(ARef);
end;

Function TRemoveReferenceVisitor.Visit(Item : TLinkedListItem) : Boolean;

Var
  I : Integer;
  UI : TUnResolvedInstance;
  R : TUnresolvedReference;
  L : TFPList;
  
begin
  UI:=TUnResolvedInstance(Item);
  R:=UI.RootUnresolved;
  L:=Nil;
  Try
    // Collect all matches.
    While (R<>Nil) do
      begin
      If R.RootMatches(FRoot) and ((FRef = '') or (FRef=UpperCase(R.FGLobal))) Then
        begin
        If Not Assigned(L) then
          L:=TFPList.Create;
        L.Add(R);
        end;
      R:=R.NextRef;
      end;
    // Remove all matches.
    IF Assigned(L) then
      begin
      For I:=0 to L.Count-1 do
        UI.FUnresolved.RemoveItem(TLinkedListitem(L[i]),True);
      end;
    // If any references are left, leave them.
    If UI.FUnResolved.Root=Nil then
      begin
      If List=Nil then
        List:=TFPList.Create;
      List.Add(UI);
      end;
  Finally
    L.Free;
  end;
  Result:=True;
end;

{ TBuildListVisitor }

Procedure TBuildListVisitor.Add(Item : TlinkedListItem);

begin
  If (List=Nil) then
    List:=TFPList.Create;
  List.Add(Item);
end;  

Destructor TBuildListVisitor.Destroy;

Var
  I : Integer;

begin
  If Assigned(List) then
    For I:=0 to List.Count-1 do
      NeedResolving.RemoveItem(TLinkedListItem(List[I]),True);
  FreeAndNil(List);
  Inherited;
end;

{ TResolveReferenceVisitor }

Function TResolveReferenceVisitor.Visit(Item : TLinkedListItem) : Boolean; 

begin
  If TUnResolvedInstance(Item).ResolveReferences then
    Add(Item);
  Result:=True;  
end;