/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: NPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is 
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or 
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * ***** END LICENSE BLOCK ***** */
#ifndef nsIFrameManager_h___
#define nsIFrameManager_h___

#include "nsISupports.h"
#include "nsIStatefulFrame.h"
#include "nsString.h"
#include "nsChangeHint.h"
#include "nsIFrame.h"

class nsIAtom;
class nsIContent;
class nsIPresContext;
class nsIPresShell;
class nsIStyleSet;
class nsStyleContext;
class nsILayoutHistoryState;
class nsStyleChangeList;
class nsPlaceholderFrame;

#define NS_IFRAMEMANAGER_IID     \
{ 0xa6cf9107, 0x15b3, 0x11d2, \
  {0x93, 0x2e, 0x00, 0x80, 0x5f, 0x8a, 0xdd, 0x32} }
  
// Option flags for GetFrameProperty() member function
#define NS_IFRAME_MGR_REMOVE_PROP   0x0001

/**
 * Frame manager interface. The frame manager serves two purposes:
 * <li>provides a service for mapping from content to frame and from out-of-flow
 * frame to placeholder frame.
 * <li>handles structural modifications to the frame model. If the frame model
 * lock can be acquired, then the changes are processed immediately; otherwise,
 * they're queued and processed later.
 */
class nsIFrameManager : public nsISupports {
public:
  NS_DEFINE_STATIC_IID_ACCESSOR(NS_IFRAMEMANAGER_IID)

  // Initialization
  NS_IMETHOD Init(nsIPresShell* aPresShell, nsIStyleSet* aStyleSet) = 0;

  /**
   * After Destroy is called, all methods should return
   * NS_ERROR_NOT_AVAILABLE.  Destroy should be called when the
   * frame tree managed by the frame manager is no longer being
   * displayed.
   */
  NS_IMETHOD Destroy() = 0;

  // Gets and sets the root frame (typically the viewport). The lifetime of the
  // root frame is controlled by the frame manager. When the frame manager is
  // destroyed it destroys the entire frame hierarchy.
  NS_IMETHOD GetRootFrame(nsIFrame** aRootFrame) const = 0;
  NS_IMETHOD SetRootFrame(nsIFrame* aRootFrame) = 0;

  // Get the canvas frame. The canvas frame may or may not exist, so the
  // argument aCanvasFrame may be nsnull.
  NS_IMETHOD GetCanvasFrame(nsIFrame** aCanvasFrame) const = 0;

  // Primary frame functions
  NS_IMETHOD GetPrimaryFrameFor(nsIContent* aContent, nsIFrame** aPrimaryFrame) = 0;
  NS_IMETHOD SetPrimaryFrameFor(nsIContent* aContent,
                                nsIFrame*   aPrimaryFrame) = 0;
  NS_IMETHOD ClearPrimaryFrameMap() = 0;

  // Placeholder frame functions
  NS_IMETHOD GetPlaceholderFrameFor(nsIFrame*  aFrame,
                                    nsIFrame** aPlaceholderFrame) const = 0;
  NS_IMETHOD RegisterPlaceholderFrame(nsPlaceholderFrame *aPlaceholderFrame) = 0;
  NS_IMETHOD UnregisterPlaceholderFrame(nsPlaceholderFrame *aPlaceholderFrame) = 0;
  NS_IMETHOD ClearPlaceholderFrameMap() = 0;

  // Mapping undisplayed content
  virtual nsStyleContext* GetUndisplayedContent(nsIContent* aContent) = 0;
  virtual void SetUndisplayedContent(nsIContent* aContent,
                                     nsStyleContext* aStyleContext) = 0;
  virtual void ChangeUndisplayedContent(nsIContent* aContent,
                                        nsStyleContext* aStyleContext) = 0;
  NS_IMETHOD ClearUndisplayedContentIn(nsIContent* aContent, nsIContent* aParentContent) = 0;
  NS_IMETHOD ClearAllUndisplayedContentIn(nsIContent* aParentContent) = 0;
  NS_IMETHOD ClearUndisplayedContentMap() = 0;

  // Functions for manipulating the frame model
  NS_IMETHOD AppendFrames(nsIFrame*       aParentFrame,
                          nsIAtom*        aListName,
                          nsIFrame*       aFrameList) = 0;
  NS_IMETHOD InsertFrames(nsIFrame*       aParentFrame,
                          nsIAtom*        aListName,
                          nsIFrame*       aPrevFrame,
                          nsIFrame*       aFrameList) = 0;
  NS_IMETHOD RemoveFrame(nsIFrame*       aParentFrame,
                         nsIAtom*        aListName,
                         nsIFrame*       aOldFrame) = 0;
  NS_IMETHOD ReplaceFrame(nsIFrame*       aParentFrame,
                          nsIAtom*        aListName,
                          nsIFrame*       aOldFrame,
                          nsIFrame*       aNewFrame) = 0;

  // Notification that we were unable to render a replaced element
  NS_IMETHOD CantRenderReplacedElement(nsIFrame*       aFrame) = 0;

  // Notification that a frame is about to be destroyed. This allows any outstanding
  // references to the frame to be cleaned up
  NS_IMETHOD NotifyDestroyingFrame(nsIFrame* aFrame) = 0;

  // reparent the style contexts of this frame sub tree to live under the
  // new given parent style context
  NS_IMETHOD ReParentStyleContext(nsIFrame* aFrame, 
                                  nsStyleContext* aNewParentContext) = 0;

  // Re-resolve style contexts for frame tree
  NS_IMETHOD ComputeStyleChangeFor(nsIFrame* aFrame, 
                                   PRInt32 aAttrNameSpaceID,
                                   nsIAtom* aAttribute,
                                   nsStyleChangeList& aChangeList,
                                   nsChangeHint aMinChange,
                                   nsChangeHint& aTopLevelChange) = 0;

  // Determine whether an attribute affects style
  NS_IMETHOD HasAttributeDependentStyle(nsIContent *aContent,
                                        nsIAtom *aAttribute,
                                        PRInt32 aModType,
                                        PRBool *aResult) = 0;

  /**
   * Capture/restore frame state for the frame subtree rooted at aFrame.
   * aState is the document state storage object onto which each frame 
   * stores its state.
   */
  NS_IMETHOD CaptureFrameState(nsIFrame* aFrame,
                               nsILayoutHistoryState* aState) = 0;
  NS_IMETHOD RestoreFrameState(nsIFrame* aFrame,
                               nsILayoutHistoryState* aState) = 0;
  // Add/restore state for one frame (special, global type, like scroll position)
  NS_IMETHOD CaptureFrameStateFor(nsIFrame* aFrame,
                                  nsILayoutHistoryState* aState,
                                  nsIStatefulFrame::SpecialStateID aID = nsIStatefulFrame::eNoID) = 0;
  NS_IMETHOD RestoreFrameStateFor(nsIFrame* aFrame,
                                  nsILayoutHistoryState* aState,
                                  nsIStatefulFrame::SpecialStateID aID = nsIStatefulFrame::eNoID) = 0;

  /**
   * Gets a property value for a given frame.
   *
   * @param   aFrame          the frame with the property
   * @param   aPropertyName   property name as an atom
   * @param   aOptions        optional flags
   *                            NS_IFRAME_MGR_REMOVE_PROP removes the property
   * @param   aPropertyValue  the property value or 0 if the property is not set
   * @return  NS_OK if the property is set,
   *          NS_IFRAME_MGR_PROP_NOT_THERE if the property is not set
   */
  NS_IMETHOD GetFrameProperty(nsIFrame* aFrame,
                              nsIAtom*  aPropertyName,
                              PRUint32  aOptions,
                              void**    aPropertyValue) = 0;
  
  /**
   * Sets the property value for a given frame.
   *
   * A frame may only have one property value at a time for a given property
   * name. The existing property value (if there is one) is overwritten, and the
   * old value destroyed
   *
   * @param   aFrame            the frame to set the property on
   * @param   aPropertyName     property name as an atom
   * @param   aPropertyValue    the property value
   * @param   aPropertyDtorFunc when setting a property you can specify the
   *                            dtor function (can be NULL) that will be used
   *                            to destroy the property value. There can be only
   *                            one dtor function for a given property name
   * @return  NS_OK if successful,
   *          NS_IFRAME_MGR_PROP_OVERWRITTEN if there is an existing property
   *            value that was overwritten,
   *          NS_ERROR_INVALID_ARG if the dtor function does not match the
   *            existing dtor function
   */
  NS_IMETHOD SetFrameProperty(nsIFrame*               aFrame,
                              nsIAtom*                aPropertyName,
                              void*                   aPropertyValue,
                              NSFramePropertyDtorFunc aPropertyDtorFunc) = 0;

  /**
   * Removes a property and destroys its property value by calling the dtor
   * function associated with the property name.
   *
   * When a frame is destroyed any remaining properties are automatically removed
   *
   * @param   aFrame          the frame to set the property on
   * @param   aPropertyName   property name as an atom
   * @return  NS_OK if the property is successfully removed,
   *          NS_IFRAME_MGR_PROP_NOT_THERE if the property is not set
   */
  NS_IMETHOD RemoveFrameProperty(nsIFrame* aFrame,
                                 nsIAtom*  aPropertyName) = 0;

#ifdef NS_DEBUG
  /**
   * DEBUG ONLY method to verify integrity of style tree versus frame tree
   */
  NS_IMETHOD DebugVerifyStyleTree(nsIFrame* aFrame) = 0;
#endif
};

/**
 * Create a frame manager. Upon success, call Init() before attempting to
 * use it.
 */
nsresult
NS_NewFrameManager(nsIFrameManager** aInstancePtrResult);

#endif /* nsIFrameManager_h___ */
