gecko/layout/base/nsIPresShell.h
2012-07-30 17:20:58 +03:00

1409 lines
51 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This Original Code has been modified by IBM Corporation.
* Modifications made by IBM described herein are
* Copyright (c) International Business Machines
* Corporation, 2000
*
* Modifications to Mozilla code or documentation
* identified per MPL Section 3.3
*
* Date Modified by Description of modification
* 05/03/2000 IBM Corp. Observer related defines for reflow
*/
/* a presentation of a document, part 2 */
#ifndef nsIPresShell_h___
#define nsIPresShell_h___
#include "nsTHashtable.h"
#include "nsHashKeys.h"
#include "nsISupports.h"
#include "nsQueryFrame.h"
#include "nsCoord.h"
#include "nsColor.h"
#include "nsEvent.h"
#include "nsCompatibility.h"
#include "nsFrameManagerBase.h"
#include "nsRect.h"
#include "mozFlushType.h"
#include "nsWeakReference.h"
#include <stdio.h> // for FILE definition
#include "nsChangeHint.h"
#include "nsGUIEvent.h"
#include "nsInterfaceHashtable.h"
#include "nsEventStates.h"
#include "nsPresArena.h"
class nsIContent;
class nsIDocument;
class nsIFrame;
class nsPresContext;
class nsStyleSet;
class nsIViewManager;
class nsIView;
class nsRenderingContext;
class nsIPageSequenceFrame;
class nsAString;
class nsCaret;
class nsFrameSelection;
class nsFrameManager;
class nsILayoutHistoryState;
class nsIReflowCallback;
class nsIDOMNode;
class nsIntRegion;
class nsIStyleSheet;
class nsCSSFrameConstructor;
class nsISelection;
template<class E> class nsCOMArray;
class nsWeakFrame;
class nsIScrollableFrame;
class gfxASurface;
class gfxContext;
class nsIDOMEvent;
class nsDisplayList;
class nsDisplayListBuilder;
class nsPIDOMWindow;
struct nsPoint;
struct nsIntPoint;
struct nsIntRect;
class nsRegion;
class nsRefreshDriver;
class nsARefreshObserver;
#ifdef ACCESSIBILITY
class nsAccessibilityService;
class DocAccessible;
#endif
class nsIWidget;
struct nsArenaMemoryStats;
typedef short SelectionType;
typedef PRUint64 nsFrameState;
namespace mozilla {
namespace dom {
class Element;
} // namespace dom
namespace layers{
class LayerManager;
} // namespace layers
} // namespace mozilla
// Flags to pass to SetCapturingContent
//
// when assigning capture, ignore whether capture is allowed or not
#define CAPTURE_IGNOREALLOWED 1
// true if events should be targeted at the capturing content or its children
#define CAPTURE_RETARGETTOELEMENT 2
// true if the current capture wants drags to be prevented
#define CAPTURE_PREVENTDRAG 4
// true when the mouse is pointer locked, and events are sent to locked elemnt
#define CAPTURE_POINTERLOCK 8
typedef struct CapturingContentInfo {
// capture should only be allowed during a mousedown event
bool mAllowed;
bool mPointerLock;
bool mRetargetToElement;
bool mPreventDrag;
nsIContent* mContent;
} CapturingContentInfo;
// fcada634-fdea-45f5-b841-0a361d5f6a68
#define NS_IPRESSHELL_IID \
{ 0xfcada634, 0xfdea, 0x45f5, \
{ 0xb8, 0x41, 0x0a, 0x36, 0x1d, 0x5f, 0x6a, 0x68 } }
// debug VerifyReflow flags
#define VERIFY_REFLOW_ON 0x01
#define VERIFY_REFLOW_NOISY 0x02
#define VERIFY_REFLOW_ALL 0x04
#define VERIFY_REFLOW_DUMP_COMMANDS 0x08
#define VERIFY_REFLOW_NOISY_RC 0x10
#define VERIFY_REFLOW_REALLY_NOISY_RC 0x20
#define VERIFY_REFLOW_DURING_RESIZE_REFLOW 0x40
#undef NOISY_INTERRUPTIBLE_REFLOW
enum nsRectVisibility {
nsRectVisibility_kVisible,
nsRectVisibility_kAboveViewport,
nsRectVisibility_kBelowViewport,
nsRectVisibility_kLeftOfViewport,
nsRectVisibility_kRightOfViewport
};
/**
* Presentation shell interface. Presentation shells are the
* controlling point for managing the presentation of a document. The
* presentation shell holds a live reference to the document, the
* presentation context, the style manager, the style set and the root
* frame. <p>
*
* When this object is Release'd, it will release the document, the
* presentation context, the style manager, the style set and the root
* frame.
*/
// hack to make egcs / gcc 2.95.2 happy
class nsIPresShell_base : public nsISupports
{
public:
NS_DECLARE_STATIC_IID_ACCESSOR(NS_IPRESSHELL_IID)
};
NS_DEFINE_STATIC_IID_ACCESSOR(nsIPresShell_base, NS_IPRESSHELL_IID)
class nsIPresShell : public nsIPresShell_base
{
protected:
typedef mozilla::layers::LayerManager LayerManager;
enum eRenderFlag {
STATE_IGNORING_VIEWPORT_SCROLLING = 0x1
};
typedef PRUint8 RenderFlags; // for storing the above flags
public:
virtual NS_HIDDEN_(nsresult) Init(nsIDocument* aDocument,
nsPresContext* aPresContext,
nsIViewManager* aViewManager,
nsStyleSet* aStyleSet,
nsCompatibility aCompatMode) = 0;
/**
* All callers are responsible for calling |Destroy| after calling
* |EndObservingDocument|. It needs to be separate only because form
* controls incorrectly store their data in the frames rather than the
* content model and printing calls |EndObservingDocument| multiple
* times to make form controls behave nicely when printed.
*/
virtual NS_HIDDEN_(void) Destroy() = 0;
bool IsDestroying() { return mIsDestroying; }
/**
* All frames owned by the shell are allocated from an arena. They
* are also recycled using free lists. Separate free lists are
* maintained for each frame type (aID), which must always correspond
* to the same aSize value. AllocateFrame returns zero-filled memory.
* AllocateFrame is fallible, it returns nullptr on out-of-memory.
*/
void* AllocateFrame(nsQueryFrame::FrameIID aID, size_t aSize)
{
#ifdef DEBUG
mPresArenaAllocCount++;
#endif
void* result = mFrameArena.AllocateByFrameID(aID, aSize);
if (result) {
memset(result, 0, aSize);
}
return result;
}
void FreeFrame(nsQueryFrame::FrameIID aID, void* aPtr)
{
#ifdef DEBUG
mPresArenaAllocCount--;
#endif
if (PRESARENA_MUST_FREE_DURING_DESTROY || !mIsDestroying)
mFrameArena.FreeByFrameID(aID, aPtr);
}
/**
* This is for allocating other types of objects (not frames). Separate free
* lists are maintained for each type (aID), which must always correspond to
* the same aSize value. AllocateByObjectID returns zero-filled memory.
* AllocateByObjectID is fallible, it returns nullptr on out-of-memory.
*/
void* AllocateByObjectID(nsPresArena::ObjectID aID, size_t aSize)
{
#ifdef DEBUG
mPresArenaAllocCount++;
#endif
void* result = mFrameArena.AllocateByObjectID(aID, aSize);
if (result) {
memset(result, 0, aSize);
}
return result;
}
void FreeByObjectID(nsPresArena::ObjectID aID, void* aPtr)
{
#ifdef DEBUG
mPresArenaAllocCount--;
#endif
if (PRESARENA_MUST_FREE_DURING_DESTROY || !mIsDestroying)
mFrameArena.FreeByObjectID(aID, aPtr);
}
/**
* Other objects closely related to the frame tree that are allocated
* from a separate set of per-size free lists. Note that different types
* of objects that has the same size are allocated from the same list.
* AllocateMisc does *not* clear the memory that it returns.
* AllocateMisc is fallible, it returns nullptr on out-of-memory.
*
* @deprecated use AllocateByObjectID/FreeByObjectID instead
*/
void* AllocateMisc(size_t aSize)
{
#ifdef DEBUG
mPresArenaAllocCount++;
#endif
return mFrameArena.AllocateBySize(aSize);
}
void FreeMisc(size_t aSize, void* aPtr)
{
#ifdef DEBUG
mPresArenaAllocCount--;
#endif
if (PRESARENA_MUST_FREE_DURING_DESTROY || !mIsDestroying)
mFrameArena.FreeBySize(aSize, aPtr);
}
nsIDocument* GetDocument() const { return mDocument; }
nsPresContext* GetPresContext() const { return mPresContext; }
nsIViewManager* GetViewManager() const { return mViewManager; }
#ifdef ACCESSIBILITY
void SetAccDocument(DocAccessible* aAccDocument)
{
mAccDocument = aAccDocument;
}
#endif
#ifdef _IMPL_NS_LAYOUT
nsStyleSet* StyleSet() const { return mStyleSet; }
nsCSSFrameConstructor* FrameConstructor() const { return mFrameConstructor; }
nsFrameManager* FrameManager() const {
// reinterpret_cast is valid since nsFrameManager does not add
// any members over nsFrameManagerBase.
return reinterpret_cast<nsFrameManager*>
(const_cast<nsIPresShell*>(this)->mFrameManager);
}
#endif
/* Enable/disable author style level. Disabling author style disables the entire
* author level of the cascade, including the HTML preshint level.
*/
// XXX these could easily be inlined, but there is a circular #include
// problem with nsStyleSet.
NS_HIDDEN_(void) SetAuthorStyleDisabled(bool aDisabled);
NS_HIDDEN_(bool) GetAuthorStyleDisabled() const;
/*
* Called when stylesheets are added/removed/enabled/disabled to rebuild
* all style data for a given pres shell without necessarily reconstructing
* all of the frames. This will not reconstruct style synchronously; if
* you need to do that, call FlushPendingNotifications to flush out style
* reresolves.
* // XXXbz why do we have this on the interface anyway? The only consumer
* is calling AddOverrideStyleSheet/RemoveOverrideStyleSheet, and I think
* those should just handle reconstructing style data...
*/
virtual NS_HIDDEN_(void) ReconstructStyleDataExternal();
NS_HIDDEN_(void) ReconstructStyleDataInternal();
#ifdef _IMPL_NS_LAYOUT
void ReconstructStyleData() { ReconstructStyleDataInternal(); }
#else
void ReconstructStyleData() { ReconstructStyleDataExternal(); }
#endif
/** Setup all style rules required to implement preferences
* - used for background/text/link colors and link underlining
* may be extended for any prefs that are implemented via style rules
* - aForceReflow argument is used to force a full reframe to make the rules show
* (only used when the current page needs to reflect changed pref rules)
*
* - initially created for bugs 31816, 20760, 22963
*/
virtual NS_HIDDEN_(nsresult) SetPreferenceStyleRules(bool aForceReflow) = 0;
/**
* FrameSelection will return the Frame based selection API.
* You cannot go back and forth anymore with QI between nsIDOM sel and
* nsIFrame sel.
*/
already_AddRefed<nsFrameSelection> FrameSelection();
/**
* ConstFrameSelection returns an object which methods are safe to use for
* example in nsIFrame code.
*/
const nsFrameSelection* ConstFrameSelection() const { return mSelection; }
// Make shell be a document observer. If called after Destroy() has
// been called on the shell, this will be ignored.
virtual NS_HIDDEN_(void) BeginObservingDocument() = 0;
// Make shell stop being a document observer
virtual NS_HIDDEN_(void) EndObservingDocument() = 0;
/**
* Return whether InitialReflow() was previously called.
*/
bool DidInitialReflow() const { return mDidInitialReflow; }
/**
* Perform the initial reflow. Constructs the frame for the root content
* object and then reflows the frame model into the specified width and
* height.
*
* The coordinates for aWidth and aHeight must be in standard nscoords.
*
* Callers of this method must hold a reference to this shell that
* is guaranteed to survive through arbitrary script execution.
* Calling InitialReflow can execute arbitrary script.
*/
virtual NS_HIDDEN_(nsresult) InitialReflow(nscoord aWidth, nscoord aHeight) = 0;
/**
* Reflow the frame model into a new width and height. The
* coordinates for aWidth and aHeight must be in standard nscoord's.
*/
virtual NS_HIDDEN_(nsresult) ResizeReflow(nscoord aWidth, nscoord aHeight) = 0;
/**
* Reflow, and also change presshell state so as to only permit
* reflowing off calls to ResizeReflowOverride() in the future.
* ResizeReflow() calls are ignored after ResizeReflowOverride().
*/
virtual NS_HIDDEN_(nsresult) ResizeReflowOverride(nscoord aWidth, nscoord aHeight) = 0;
/**
* Returns true if ResizeReflowOverride has been called.
*/
virtual bool GetIsViewportOverridden() = 0;
/**
* Return true if the presshell expects layout flush.
*/
virtual bool IsLayoutFlushObserver() = 0;
/**
* Reflow the frame model with a reflow reason of eReflowReason_StyleChange
*/
virtual NS_HIDDEN_(void) StyleChangeReflow() = 0;
/**
* This calls through to the frame manager to get the root frame.
*/
virtual NS_HIDDEN_(nsIFrame*) GetRootFrameExternal() const;
nsIFrame* GetRootFrame() const {
#ifdef _IMPL_NS_LAYOUT
return mFrameManager->GetRootFrame();
#else
return GetRootFrameExternal();
#endif
}
/*
* Get root scroll frame from FrameManager()->GetRootFrame().
*/
nsIFrame* GetRootScrollFrame() const;
/*
* The same as GetRootScrollFrame, but returns an nsIScrollableFrame
*/
nsIScrollableFrame* GetRootScrollFrameAsScrollable() const;
/*
* The same as GetRootScrollFrame, but returns an nsIScrollableFrame.
* Can be called by code not linked into gklayout.
*/
virtual nsIScrollableFrame* GetRootScrollFrameAsScrollableExternal() const;
/*
* Gets nearest scrollable frame from current focused content or DOM
* selection if there is no focused content. The frame is scrollable with
* overflow:scroll or overflow:auto in some direction when aDirection is
* eEither. Otherwise, this returns a nearest frame that is scrollable in
* the specified direction.
*/
enum ScrollDirection { eHorizontal, eVertical, eEither };
nsIScrollableFrame* GetFrameToScrollAsScrollable(ScrollDirection aDirection);
/**
* Returns the page sequence frame associated with the frame hierarchy.
* Returns NULL if not a paginated view.
*/
virtual NS_HIDDEN_(nsIPageSequenceFrame*) GetPageSequenceFrame() const = 0;
/**
* Gets the real primary frame associated with the content object.
*
* In the case of absolutely positioned elements and floated elements,
* the real primary frame is the frame that is out of the flow and not the
* placeholder frame.
*/
virtual NS_HIDDEN_(nsIFrame*) GetRealPrimaryFrameFor(nsIContent* aContent) const = 0;
/**
* Gets the placeholder frame associated with the specified frame. This is
* a helper frame that forwards the request to the frame manager.
*/
virtual NS_HIDDEN_(nsIFrame*) GetPlaceholderFrameFor(nsIFrame* aFrame) const = 0;
/**
* Tell the pres shell that a frame needs to be marked dirty and needs
* Reflow. It's OK if this is an ancestor of the frame needing reflow as
* long as the ancestor chain between them doesn't cross a reflow root. The
* bit to add should be either NS_FRAME_IS_DIRTY or
* NS_FRAME_HAS_DIRTY_CHILDREN (but not both!).
*/
enum IntrinsicDirty {
// XXXldb eResize should be renamed
eResize, // don't mark any intrinsic widths dirty
eTreeChange, // mark intrinsic widths dirty on aFrame and its ancestors
eStyleChange // Do eTreeChange, plus all of aFrame's descendants
};
virtual NS_HIDDEN_(void) FrameNeedsReflow(nsIFrame *aFrame,
IntrinsicDirty aIntrinsicDirty,
nsFrameState aBitToAdd) = 0;
/**
* Tell the presshell that the given frame's reflow was interrupted. This
* will mark as having dirty children a path from the given frame (inclusive)
* to the nearest ancestor with a dirty subtree, or to the reflow root
* currently being reflowed if no such ancestor exists (inclusive). This is
* to be done immediately after reflow of the current reflow root completes.
* This method must only be called during reflow, and the frame it's being
* called on must be in the process of being reflowed when it's called. This
* method doesn't mark any intrinsic widths dirty and doesn't add any bits
* other than NS_FRAME_HAS_DIRTY_CHILDREN.
*/
virtual NS_HIDDEN_(void) FrameNeedsToContinueReflow(nsIFrame *aFrame) = 0;
virtual NS_HIDDEN_(void) CancelAllPendingReflows() = 0;
/**
* Recreates the frames for a node
*/
virtual NS_HIDDEN_(nsresult) RecreateFramesFor(nsIContent* aContent) = 0;
void PostRecreateFramesFor(mozilla::dom::Element* aElement);
void RestyleForAnimation(mozilla::dom::Element* aElement,
nsRestyleHint aHint);
/**
* Determine if it is safe to flush all pending notifications
* @param aIsSafeToFlush true if it is safe, false otherwise.
*
*/
virtual NS_HIDDEN_(bool) IsSafeToFlush() const = 0;
/**
* Flush pending notifications of the type specified. This method
* will not affect the content model; it'll just affect style and
* frames. Callers that actually want up-to-date presentation (other
* than the document itself) should probably be calling
* nsIDocument::FlushPendingNotifications.
*
* @param aType the type of notifications to flush
*/
virtual NS_HIDDEN_(void) FlushPendingNotifications(mozFlushType aType) = 0;
/**
* Callbacks will be called even if reflow itself fails for
* some reason.
*/
virtual NS_HIDDEN_(nsresult) PostReflowCallback(nsIReflowCallback* aCallback) = 0;
virtual NS_HIDDEN_(void) CancelReflowCallback(nsIReflowCallback* aCallback) = 0;
virtual NS_HIDDEN_(void) ClearFrameRefs(nsIFrame* aFrame) = 0;
/**
* Get a reference rendering context. This is a context that should not
* be rendered to, but is suitable for measuring text and performing
* other non-rendering operations.
*/
virtual already_AddRefed<nsRenderingContext> GetReferenceRenderingContext() = 0;
/**
* Informs the pres shell that the document is now at the anchor with
* the given name. If |aScroll| is true, scrolls the view of the
* document so that the anchor with the specified name is displayed at
* the top of the window. If |aAnchorName| is empty, then this informs
* the pres shell that there is no current target, and |aScroll| must
* be false.
*/
virtual NS_HIDDEN_(nsresult) GoToAnchor(const nsAString& aAnchorName, bool aScroll) = 0;
/**
* Tells the presshell to scroll again to the last anchor scrolled to by
* GoToAnchor, if any. This scroll only happens if the scroll
* position has not changed since the last GoToAnchor. This is called
* by nsDocumentViewer::LoadComplete. This clears the last anchor
* scrolled to by GoToAnchor (we don't want to keep it alive if it's
* removed from the DOM), so don't call this more than once.
*/
virtual NS_HIDDEN_(nsresult) ScrollToAnchor() = 0;
enum {
SCROLL_TOP = 0,
SCROLL_BOTTOM = 100,
SCROLL_LEFT = 0,
SCROLL_RIGHT = 100,
SCROLL_CENTER = 50,
SCROLL_MINIMUM = -1
};
enum WhenToScroll {
SCROLL_ALWAYS,
SCROLL_IF_NOT_VISIBLE,
SCROLL_IF_NOT_FULLY_VISIBLE
};
typedef struct ScrollAxis {
PRInt16 mWhereToScroll;
WhenToScroll mWhenToScroll : 16;
/**
* @param aWhere: Either a percentage or a special value.
* nsIPresShell defines:
* * (Default) SCROLL_MINIMUM = -1: The visible area is
* scrolled to show the entire frame. If the frame is too
* large, the top and left edges are given precedence.
* * SCROLL_TOP = 0: The frame's upper edge is aligned with the
* top edge of the visible area.
* * SCROLL_BOTTOM = 100: The frame's bottom edge is aligned
* with the bottom edge of the visible area.
* * SCROLL_LEFT = 0: The frame's left edge is aligned with the
* left edge of the visible area.
* * SCROLL_RIGHT = 100: The frame's right edge is aligned with
* the right edge of the visible area.
* * SCROLL_CENTER = 50: The frame is centered along the axis
* the ScrollAxis is used for.
*
* Other values are treated as a percentage, and the point
* "percent" down the frame is placed at the point "percent"
* down the visible area.
* @param aWhen:
* * (Default) SCROLL_IF_NOT_FULLY_VISIBLE: Move the frame only
* if it is not fully visible (including if it's not visible
* at all). Note that in this case if the frame is too large to
* fit in view, it will only be scrolled if more of it can fit
* than is already in view.
* * SCROLL_IF_NOT_VISIBLE: Move the frame only if none of it
* is visible.
* * SCROLL_ALWAYS: Move the frame regardless of its current
* visibility.
*/
ScrollAxis(PRInt16 aWhere = SCROLL_MINIMUM,
WhenToScroll aWhen = SCROLL_IF_NOT_FULLY_VISIBLE) :
mWhereToScroll(aWhere), mWhenToScroll(aWhen) {}
} ScrollAxis;
/**
* Scrolls the view of the document so that the primary frame of the content
* is displayed in the window. Layout is flushed before scrolling.
*
* @param aContent The content object of which primary frame should be
* scrolled into view.
* @param aVertical How to align the frame vertically and when to do so.
* This is a ScrollAxis of Where and When.
* @param aHorizontal How to align the frame horizontally and when to do so.
* This is a ScrollAxis of Where and When.
* @param aFlags If SCROLL_FIRST_ANCESTOR_ONLY is set, only the nearest
* scrollable ancestor is scrolled, otherwise all
* scrollable ancestors may be scrolled if necessary.
* If SCROLL_OVERFLOW_HIDDEN is set then we may scroll in a
* direction even if overflow:hidden is specified in that
* direction; otherwise we will not scroll in that direction
* when overflow:hidden is set for that direction.
* If SCROLL_NO_PARENT_FRAMES is set then we only scroll
* nodes in this document, not in any parent documents which
* contain this document in a iframe or the like.
*/
virtual NS_HIDDEN_(nsresult) ScrollContentIntoView(nsIContent* aContent,
ScrollAxis aVertical,
ScrollAxis aHorizontal,
PRUint32 aFlags) = 0;
enum {
SCROLL_FIRST_ANCESTOR_ONLY = 0x01,
SCROLL_OVERFLOW_HIDDEN = 0x02,
SCROLL_NO_PARENT_FRAMES = 0x04
};
/**
* Scrolls the view of the document so that the given area of a frame
* is visible, if possible. Layout is not flushed before scrolling.
*
* @param aRect relative to aFrame
* @param aVertical see ScrollContentIntoView and ScrollAxis
* @param aHorizontal see ScrollContentIntoView and ScrollAxis
* @param aFlags if SCROLL_FIRST_ANCESTOR_ONLY is set, only the
* nearest scrollable ancestor is scrolled, otherwise all
* scrollable ancestors may be scrolled if necessary
* if SCROLL_OVERFLOW_HIDDEN is set then we may scroll in a direction
* even if overflow:hidden is specified in that direction; otherwise
* we will not scroll in that direction when overflow:hidden is
* set for that direction
* If SCROLL_NO_PARENT_FRAMES is set then we only scroll
* nodes in this document, not in any parent documents which
* contain this document in a iframe or the like.
* @return true if any scrolling happened, false if no scrolling happened
*/
virtual bool ScrollFrameRectIntoView(nsIFrame* aFrame,
const nsRect& aRect,
ScrollAxis aVertical,
ScrollAxis aHorizontal,
PRUint32 aFlags) = 0;
/**
* Determine if a rectangle specified in the frame's coordinate system
* intersects the viewport "enough" to be considered visible.
* @param aFrame frame that aRect coordinates are specified relative to
* @param aRect rectangle in twips to test for visibility
* @param aMinTwips is the minimum distance in from the edge of the viewport
* that an object must be to be counted visible
* @return nsRectVisibility_kVisible if the rect is visible
* nsRectVisibility_kAboveViewport
* nsRectVisibility_kBelowViewport
* nsRectVisibility_kLeftOfViewport
* nsRectVisibility_kRightOfViewport rectangle is outside the viewport
* in the specified direction
*/
virtual nsRectVisibility GetRectVisibility(nsIFrame *aFrame,
const nsRect &aRect,
nscoord aMinTwips) const = 0;
/**
* Suppress notification of the frame manager that frames are
* being destroyed.
*/
virtual NS_HIDDEN_(void) SetIgnoreFrameDestruction(bool aIgnore) = 0;
/**
* Notification sent by a frame informing the pres shell that it is about to
* be destroyed.
* This allows any outstanding references to the frame to be cleaned up
*/
virtual NS_HIDDEN_(void) NotifyDestroyingFrame(nsIFrame* aFrame) = 0;
/**
* Get the caret, if it exists. AddRefs it.
*/
virtual NS_HIDDEN_(already_AddRefed<nsCaret>) GetCaret() const = 0;
/**
* Invalidate the caret's current position if it's outside of its frame's
* boundaries. This function is useful if you're batching selection
* notifications and might remove the caret's frame out from under it.
*/
virtual NS_HIDDEN_(void) MaybeInvalidateCaretPosition() = 0;
/**
* Set the current caret to a new caret. To undo this, call RestoreCaret.
*/
virtual void SetCaret(nsCaret *aNewCaret) = 0;
/**
* Restore the caret to the original caret that this pres shell was created
* with.
*/
virtual void RestoreCaret() = 0;
/**
* Should the images have borders etc. Actual visual effects are determined
* by the frames. Visual effects may not effect layout, only display.
* Takes effect on next repaint, does not force a repaint itself.
*
* @param aInEnable if true, visual selection effects are enabled
* if false visual selection effects are disabled
*/
NS_IMETHOD SetSelectionFlags(PRInt16 aInEnable) = 0;
/**
* Gets the current state of non text selection effects
* @return current state of non text selection,
* as set by SetDisplayNonTextSelection
*/
PRInt16 GetSelectionFlags() const { return mSelectionFlags; }
virtual nsISelection* GetCurrentSelection(SelectionType aType) = 0;
/**
* Interface to dispatch events via the presshell
* @note The caller must have a strong reference to the PresShell.
*/
virtual NS_HIDDEN_(nsresult) HandleEventWithTarget(nsEvent* aEvent,
nsIFrame* aFrame,
nsIContent* aContent,
nsEventStatus* aStatus) = 0;
/**
* Dispatch event to content only (NOT full processing)
* @note The caller must have a strong reference to the PresShell.
*/
virtual NS_HIDDEN_(nsresult) HandleDOMEventWithTarget(nsIContent* aTargetContent,
nsEvent* aEvent,
nsEventStatus* aStatus) = 0;
/**
* Dispatch event to content only (NOT full processing)
* @note The caller must have a strong reference to the PresShell.
*/
virtual NS_HIDDEN_(nsresult) HandleDOMEventWithTarget(nsIContent* aTargetContent,
nsIDOMEvent* aEvent,
nsEventStatus* aStatus) = 0;
/**
* Gets the current target event frame from the PresShell
*/
virtual NS_HIDDEN_(nsIFrame*) GetEventTargetFrame() = 0;
/**
* Gets the current target event frame from the PresShell
*/
virtual NS_HIDDEN_(already_AddRefed<nsIContent>) GetEventTargetContent(nsEvent* aEvent) = 0;
/**
* Get and set the history state for the current document
*/
virtual NS_HIDDEN_(nsresult) CaptureHistoryState(nsILayoutHistoryState** aLayoutHistoryState, bool aLeavingPage = false) = 0;
/**
* Determine if reflow is currently locked
* returns true if reflow is locked, false otherwise
*/
bool IsReflowLocked() const { return mIsReflowing; }
/**
* Called to find out if painting is suppressed for this presshell. If it is suppressd,
* we don't allow the painting of any layer but the background, and we don't
* recur into our children.
*/
bool IsPaintingSuppressed() const { return mPaintingSuppressed; }
/**
* Unsuppress painting.
*/
virtual NS_HIDDEN_(void) UnsuppressPainting() = 0;
/**
* Called to disable nsITheme support in a specific presshell.
*/
void DisableThemeSupport()
{
// Doesn't have to be dynamic. Just set the bool.
mIsThemeSupportDisabled = true;
}
/**
* Indicates whether theme support is enabled.
*/
bool IsThemeSupportEnabled() const { return !mIsThemeSupportDisabled; }
/**
* Get the set of agent style sheets for this presentation
*/
virtual nsresult GetAgentStyleSheets(nsCOMArray<nsIStyleSheet>& aSheets) = 0;
/**
* Replace the set of agent style sheets
*/
virtual nsresult SetAgentStyleSheets(const nsCOMArray<nsIStyleSheet>& aSheets) = 0;
/**
* Add an override style sheet for this presentation
*/
virtual nsresult AddOverrideStyleSheet(nsIStyleSheet *aSheet) = 0;
/**
* Remove an override style sheet
*/
virtual nsresult RemoveOverrideStyleSheet(nsIStyleSheet *aSheet) = 0;
/**
* Reconstruct frames for all elements in the document
*/
virtual nsresult ReconstructFrames() = 0;
/**
* Notify that a content node's state has changed
*/
virtual void ContentStateChanged(nsIDocument* aDocument,
nsIContent* aContent,
nsEventStates aStateMask) = 0;
/**
* Given aFrame, the root frame of a stacking context, find its descendant
* frame under the point aPt that receives a mouse event at that location,
* or nullptr if there is no such frame.
* @param aPt the point, relative to the frame origin
*/
virtual nsIFrame* GetFrameForPoint(nsIFrame* aFrame, nsPoint aPt) = 0;
/**
* See if reflow verification is enabled. To enable reflow verification add
* "verifyreflow:1" to your NSPR_LOG_MODULES environment variable
* (any non-zero debug level will work). Or, call SetVerifyReflowEnable
* with true.
*/
static bool GetVerifyReflowEnable();
/**
* Set the verify-reflow enable flag.
*/
static void SetVerifyReflowEnable(bool aEnabled);
virtual nsIFrame* GetAbsoluteContainingBlock(nsIFrame* aFrame);
#ifdef MOZ_REFLOW_PERF
virtual NS_HIDDEN_(void) DumpReflows() = 0;
virtual NS_HIDDEN_(void) CountReflows(const char * aName, nsIFrame * aFrame) = 0;
virtual NS_HIDDEN_(void) PaintCount(const char * aName,
nsRenderingContext* aRenderingContext,
nsPresContext * aPresContext,
nsIFrame * aFrame,
const nsPoint& aOffset,
PRUint32 aColor) = 0;
virtual NS_HIDDEN_(void) SetPaintFrameCount(bool aOn) = 0;
virtual bool IsPaintingFrameCounts() = 0;
#endif
#ifdef DEBUG
// Debugging hooks
virtual void ListStyleContexts(nsIFrame *aRootFrame, FILE *out,
PRInt32 aIndent = 0) = 0;
virtual void ListStyleSheets(FILE *out, PRInt32 aIndent = 0) = 0;
virtual void VerifyStyleTree() = 0;
#endif
#ifdef ACCESSIBILITY
/**
* Return true if accessibility is active.
*/
static bool IsAccessibilityActive();
/**
* Return accessibility service if accessibility is active.
*/
static nsAccessibilityService* AccService();
#endif
/**
* Stop all active elements (plugins and the caret) in this presentation and
* in the presentations of subdocuments. Resets painting to a suppressed state.
* XXX this should include image animations
*/
virtual void Freeze() = 0;
bool IsFrozen() { return mFrozen; }
/**
* Restarts active elements (plugins) in this presentation and in the
* presentations of subdocuments, then do a full invalidate of the content area.
*/
virtual void Thaw() = 0;
virtual void FireOrClearDelayedEvents(bool aFireEvents) = 0;
/**
* When this shell is disconnected from its containing docshell, we
* lose our container pointer. However, we'd still like to be able to target
* user events at the docshell's parent. This pointer allows us to do that.
* It should not be used for any other purpose.
*/
void SetForwardingContainer(nsWeakPtr aContainer)
{
mForwardingContainer = aContainer;
}
/**
* Render the document into an arbitrary gfxContext
* Designed for getting a picture of a document or a piece of a document
* Note that callers will generally want to call FlushPendingNotifications
* to get an up-to-date view of the document
* @param aRect is the region to capture into the offscreen buffer, in the
* root frame's coordinate system (if aIgnoreViewportScrolling is false)
* or in the root scrolled frame's coordinate system
* (if aIgnoreViewportScrolling is true). The coordinates are in appunits.
* @param aFlags see below;
* set RENDER_IS_UNTRUSTED if the contents may be passed to malicious
* agents. E.g. we might choose not to paint the contents of sensitive widgets
* such as the file name in a file upload widget, and we might choose not
* to paint themes.
* set RENDER_IGNORE_VIEWPORT_SCROLLING to ignore
* clipping/scrolling/scrollbar painting due to scrolling in the viewport
* set RENDER_CARET to draw the caret if one would be visible
* (by default the caret is never drawn)
* set RENDER_USE_LAYER_MANAGER to force rendering to go through
* the layer manager for the window. This may be unexpectedly slow
* (if the layer manager must read back data from the GPU) or low-quality
* (if the layer manager reads back pixel data and scales it
* instead of rendering using the appropriate scaling). It may also
* slow everything down if the area rendered does not correspond to the
* normal visible area of the window.
* set RENDER_ASYNC_DECODE_IMAGES to avoid having images synchronously
* decoded during rendering.
* (by default images decode synchronously with RenderDocument)
* set RENDER_DOCUMENT_RELATIVE to interpret |aRect| relative to the
* document instead of the CSS viewport
* @param aBackgroundColor a background color to render onto
* @param aRenderedContext the gfxContext to render to. We render so that
* one CSS pixel in the source document is rendered to one unit in the current
* transform.
*/
enum {
RENDER_IS_UNTRUSTED = 0x01,
RENDER_IGNORE_VIEWPORT_SCROLLING = 0x02,
RENDER_CARET = 0x04,
RENDER_USE_WIDGET_LAYERS = 0x08,
RENDER_ASYNC_DECODE_IMAGES = 0x10,
RENDER_DOCUMENT_RELATIVE = 0x20
};
virtual NS_HIDDEN_(nsresult) RenderDocument(const nsRect& aRect, PRUint32 aFlags,
nscolor aBackgroundColor,
gfxContext* aRenderedContext) = 0;
/**
* Renders a node aNode to a surface and returns it. The aRegion may be used
* to clip the rendering. This region is measured in CSS pixels from the
* edge of the presshell area. The aPoint, aScreenRect and aSurface
* arguments function in a similar manner as RenderSelection.
*/
virtual already_AddRefed<gfxASurface> RenderNode(nsIDOMNode* aNode,
nsIntRegion* aRegion,
nsIntPoint& aPoint,
nsIntRect* aScreenRect) = 0;
/**
* Renders a selection to a surface and returns it. This method is primarily
* intended to create the drag feedback when dragging a selection.
*
* aScreenRect will be filled in with the bounding rectangle of the
* selection area on screen.
*
* If the area of the selection is large, the image will be scaled down.
* The argument aPoint is used in this case as a reference point when
* determining the new screen rectangle after scaling. Typically, this
* will be the mouse position, so that the screen rectangle is positioned
* such that the mouse is over the same point in the scaled image as in
* the original. When scaling does not occur, the mouse point isn't used
* as the position can be determined from the displayed frames.
*/
virtual already_AddRefed<gfxASurface> RenderSelection(nsISelection* aSelection,
nsIntPoint& aPoint,
nsIntRect* aScreenRect) = 0;
void AddWeakFrameInternal(nsWeakFrame* aWeakFrame);
virtual void AddWeakFrameExternal(nsWeakFrame* aWeakFrame);
void AddWeakFrame(nsWeakFrame* aWeakFrame)
{
#ifdef _IMPL_NS_LAYOUT
AddWeakFrameInternal(aWeakFrame);
#else
AddWeakFrameExternal(aWeakFrame);
#endif
}
void RemoveWeakFrameInternal(nsWeakFrame* aWeakFrame);
virtual void RemoveWeakFrameExternal(nsWeakFrame* aWeakFrame);
void RemoveWeakFrame(nsWeakFrame* aWeakFrame)
{
#ifdef _IMPL_NS_LAYOUT
RemoveWeakFrameInternal(aWeakFrame);
#else
RemoveWeakFrameExternal(aWeakFrame);
#endif
}
#ifdef DEBUG
nsIFrame* GetDrawEventTargetFrame() { return mDrawEventTargetFrame; }
#endif
/**
* Stop or restart non synthetic test mouse event handling on *all*
* presShells.
*
* @param aDisable If true, disable all non synthetic test mouse
* events on all presShells. Otherwise, enable them.
*/
virtual NS_HIDDEN_(void) DisableNonTestMouseEvents(bool aDisable) = 0;
/**
* Record the background color of the most recently drawn canvas. This color
* is composited on top of the user's default background color and then used
* to draw the background color of the canvas. See PresShell::Paint,
* PresShell::PaintDefaultBackground, and nsDocShell::SetupNewViewer;
* bug 488242, bug 476557 and other bugs mentioned there.
*/
void SetCanvasBackground(nscolor aColor) { mCanvasBackgroundColor = aColor; }
nscolor GetCanvasBackground() { return mCanvasBackgroundColor; }
/**
* Use the current frame tree (if it exists) to update the background
* color of the most recently drawn canvas.
*/
virtual void UpdateCanvasBackground() = 0;
/**
* Add a solid color item to the bottom of aList with frame aFrame and bounds
* aBounds. Checks first if this needs to be done by checking if aFrame is a
* canvas frame (if the FORCE_DRAW flag is passed then this check is skipped).
* aBackstopColor is composed behind the background color of the canvas, it is
* transparent by default.
*/
enum {
FORCE_DRAW = 0x01
};
virtual nsresult AddCanvasBackgroundColorItem(nsDisplayListBuilder& aBuilder,
nsDisplayList& aList,
nsIFrame* aFrame,
const nsRect& aBounds,
nscolor aBackstopColor = NS_RGBA(0,0,0,0),
PRUint32 aFlags = 0) = 0;
/**
* Add a solid color item to the bottom of aList with frame aFrame and
* bounds aBounds representing the dark grey background behind the page of a
* print preview presentation.
*/
virtual nsresult AddPrintPreviewBackgroundItem(nsDisplayListBuilder& aBuilder,
nsDisplayList& aList,
nsIFrame* aFrame,
const nsRect& aBounds) = 0;
/**
* Computes the backstop color for the view: transparent if in a transparent
* widget, otherwise the PresContext default background color. This color is
* only visible if the contents of the view as a whole are translucent.
*/
virtual nscolor ComputeBackstopColor(nsIView* aDisplayRoot) = 0;
void ObserveNativeAnonMutationsForPrint(bool aObserve)
{
mObservesMutationsForPrint = aObserve;
}
bool ObservesNativeAnonMutationsForPrint()
{
return mObservesMutationsForPrint;
}
virtual nsresult SetIsActive(bool aIsActive) = 0;
bool IsActive()
{
return mIsActive;
}
// mouse capturing
static CapturingContentInfo gCaptureInfo;
static nsInterfaceHashtable<nsUint32HashKey, nsIDOMTouch> gCaptureTouchList;
static bool gPreventMouseEvents;
/**
* When capturing content is set, it traps all mouse events and retargets
* them at this content node. If capturing is not allowed
* (gCaptureInfo.mAllowed is false), then capturing is not set. However, if
* the CAPTURE_IGNOREALLOWED flag is set, the allowed state is ignored and
* capturing is set regardless. To disable capture, pass null for the value
* of aContent.
*
* If CAPTURE_RETARGETTOELEMENT is set, all mouse events are targeted at
* aContent only. Otherwise, mouse events are targeted at aContent or its
* descendants. That is, descendants of aContent receive mouse events as
* they normally would, but mouse events outside of aContent are retargeted
* to aContent.
*
* If CAPTURE_PREVENTDRAG is set then drags are prevented from starting while
* this capture is active.
*
* If CAPTURE_POINTERLOCK is set, similar to CAPTURE_RETARGETTOELEMENT, then
* events are targeted at aContent, but capturing is held more strongly (i.e.,
* calls to SetCapturingContent won't unlock unless CAPTURE_POINTERLOCK is
* set again).
*/
static void SetCapturingContent(nsIContent* aContent, PRUint8 aFlags);
/**
* Return the active content currently capturing the mouse if any.
*/
static nsIContent* GetCapturingContent()
{
return gCaptureInfo.mContent;
}
/**
* Allow or disallow mouse capturing.
*/
static void AllowMouseCapture(bool aAllowed)
{
gCaptureInfo.mAllowed = aAllowed;
}
/**
* Returns true if there is an active mouse capture that wants to prevent
* drags.
*/
static bool IsMouseCapturePreventingDrag()
{
return gCaptureInfo.mPreventDrag && gCaptureInfo.mContent;
}
/**
* Keep track of how many times this presshell has been rendered to
* a window.
*/
PRUint64 GetPaintCount() { return mPaintCount; }
void IncrementPaintCount() { ++mPaintCount; }
/**
* Get the root DOM window of this presShell.
*/
virtual already_AddRefed<nsPIDOMWindow> GetRootWindow() = 0;
/**
* Get the layer manager for the widget of the root view, if it has
* one.
*/
virtual LayerManager* GetLayerManager() = 0;
/**
* Track whether we're ignoring viewport scrolling for the purposes
* of painting. If we are ignoring, then layers aren't clipped to
* the CSS viewport and scrollbars aren't drawn.
*/
virtual void SetIgnoreViewportScrolling(bool aIgnore) = 0;
bool IgnoringViewportScrolling() const
{ return mRenderFlags & STATE_IGNORING_VIEWPORT_SCROLLING; }
/**
* Set a "resolution" for the document, which if not 1.0 will
* allocate more or fewer pixels for rescalable content by a factor
* of |resolution| in both dimensions. Return NS_OK iff the
* resolution bounds are sane, and the resolution of this was
* actually updated.
*
* The resolution defaults to 1.0.
*/
virtual nsresult SetResolution(float aXResolution, float aYResolution) = 0;
float GetXResolution() { return mXResolution; }
float GetYResolution() { return mYResolution; }
/**
* Set the isFirstPaint flag.
*/
void SetIsFirstPaint(bool aIsFirstPaint) { mIsFirstPaint = aIsFirstPaint; }
/**
* Get the isFirstPaint flag.
*/
bool GetIsFirstPaint() const { return mIsFirstPaint; }
/**
* Dispatch a mouse move event based on the most recent mouse position if
* this PresShell is visible. This is used when the contents of the page
* moved (aFromScroll is false) or scrolled (aFromScroll is true).
*/
virtual void SynthesizeMouseMove(bool aFromScroll) = 0;
virtual void Paint(nsIView* aViewToPaint, nsIWidget* aWidget,
const nsRegion& aDirtyRegion, const nsIntRegion& aIntDirtyRegion,
bool aWillSendDidPaint) = 0;
virtual nsresult HandleEvent(nsIFrame* aFrame,
nsGUIEvent* aEvent,
bool aDontRetargetEvents,
nsEventStatus* aEventStatus) = 0;
virtual bool ShouldIgnoreInvalidation() = 0;
/**
* Notify that the NS_WILL_PAINT event was received. Fires on every
* visible presshell in the document tree.
*/
virtual void WillPaint(bool aWillSendDidPaint) = 0;
/**
* Notify that the NS_DID_PAINT event was received. Only fires on the
* root pres shell.
*/
virtual void DidPaint() = 0;
virtual void ScheduleViewManagerFlush() = 0;
virtual void ClearMouseCaptureOnView(nsIView* aView) = 0;
virtual bool IsVisible() = 0;
virtual void DispatchSynthMouseMove(nsGUIEvent *aEvent, bool aFlushOnHoverChange) = 0;
virtual void SizeOfIncludingThis(nsMallocSizeOfFun aMallocSizeOf,
nsArenaMemoryStats *aArenaObjectsSize,
size_t *aPresShellSize,
size_t *aStyleSetsSize,
size_t *aTextRunsSize,
size_t *aPresContextSize) = 0;
/**
* Methods that retrieve the cached font inflation preferences.
*/
PRUint32 FontSizeInflationEmPerLine() const {
return mFontSizeInflationEmPerLine;
}
PRUint32 FontSizeInflationMinTwips() const {
return mFontSizeInflationMinTwips;
}
PRUint32 FontSizeInflationLineThreshold() const {
return mFontSizeInflationLineThreshold;
}
/**
* Refresh observer management.
*/
protected:
virtual bool AddRefreshObserverExternal(nsARefreshObserver* aObserver,
mozFlushType aFlushType);
bool AddRefreshObserverInternal(nsARefreshObserver* aObserver,
mozFlushType aFlushType);
virtual bool RemoveRefreshObserverExternal(nsARefreshObserver* aObserver,
mozFlushType aFlushType);
bool RemoveRefreshObserverInternal(nsARefreshObserver* aObserver,
mozFlushType aFlushType);
public:
bool AddRefreshObserver(nsARefreshObserver* aObserver,
mozFlushType aFlushType) {
#ifdef _IMPL_NS_LAYOUT
return AddRefreshObserverInternal(aObserver, aFlushType);
#else
return AddRefreshObserverExternal(aObserver, aFlushType);
#endif
}
bool RemoveRefreshObserver(nsARefreshObserver* aObserver,
mozFlushType aFlushType) {
#ifdef _IMPL_NS_LAYOUT
return RemoveRefreshObserverInternal(aObserver, aFlushType);
#else
return RemoveRefreshObserverExternal(aObserver, aFlushType);
#endif
}
/**
* Initialize and shut down static variables.
*/
static void InitializeStatics();
static void ReleaseStatics();
// If a frame in the subtree rooted at aFrame is capturing the mouse then
// clears that capture.
static void ClearMouseCapture(nsIFrame* aFrame);
void SetScrollPositionClampingScrollPortSize(nscoord aWidth, nscoord aHeight);
bool IsScrollPositionClampingScrollPortSizeSet() {
return mScrollPositionClampingScrollPortSizeSet;
}
nsSize GetScrollPositionClampingScrollPortSize() {
NS_ASSERTION(mScrollPositionClampingScrollPortSizeSet, "asking for scroll port when its not set?");
return mScrollPositionClampingScrollPortSize;
}
protected:
friend class nsRefreshDriver;
// IMPORTANT: The ownership implicit in the following member variables
// has been explicitly checked. If you add any members to this class,
// please make the ownership explicit (pinkerton, scc).
// These are the same Document and PresContext owned by the DocViewer.
// we must share ownership.
nsIDocument* mDocument; // [STRONG]
nsPresContext* mPresContext; // [STRONG]
nsStyleSet* mStyleSet; // [OWNS]
nsCSSFrameConstructor* mFrameConstructor; // [OWNS]
nsIViewManager* mViewManager; // [WEAK] docViewer owns it so I don't have to
nsPresArena mFrameArena;
nsFrameSelection* mSelection;
// Pointer into mFrameConstructor - this is purely so that FrameManager() and
// GetRootFrame() can be inlined:
nsFrameManagerBase* mFrameManager;
nsWeakPtr mForwardingContainer;
#ifdef ACCESSIBILITY
DocAccessible* mAccDocument;
#endif
#ifdef DEBUG
nsIFrame* mDrawEventTargetFrame;
// Ensure that every allocation from the PresArena is eventually freed.
PRUint32 mPresArenaAllocCount;
#endif
// Count of the number of times this presshell has been painted to a window.
PRUint64 mPaintCount;
nsSize mScrollPositionClampingScrollPortSize;
// A list of weak frames. This is a pointer to the last item in the list.
nsWeakFrame* mWeakFrames;
// Most recent canvas background color.
nscolor mCanvasBackgroundColor;
// Used to force allocation and rendering of proportionally more or
// less pixels in the given dimension.
float mXResolution;
float mYResolution;
PRInt16 mSelectionFlags;
// Flags controlling how our document is rendered. These persist
// between paints and so are tied with retained layer pixels.
// PresShell flushes retained layers when the rendering state
// changes in a way that prevents us from being able to (usefully)
// re-use old pixels.
RenderFlags mRenderFlags;
bool mStylesHaveChanged : 1;
bool mDidInitialReflow : 1;
bool mIsDestroying : 1;
bool mIsReflowing : 1;
// For all documents we initially lock down painting.
bool mPaintingSuppressed : 1;
// Whether or not form controls should use nsITheme in this shell.
bool mIsThemeSupportDisabled : 1;
bool mIsActive : 1;
bool mFrozen : 1;
bool mIsFirstPaint : 1;
bool mObservesMutationsForPrint : 1;
// If true, we have a reflow scheduled. Guaranteed to be false if
// mReflowContinueTimer is non-null.
bool mReflowScheduled : 1;
bool mSuppressInterruptibleReflows : 1;
bool mScrollPositionClampingScrollPortSizeSet : 1;
static nsIContent* gKeyDownTarget;
// Cached font inflation values. This is done to prevent changing of font
// inflation until a page is reloaded.
PRUint32 mFontSizeInflationEmPerLine;
PRUint32 mFontSizeInflationMinTwips;
PRUint32 mFontSizeInflationLineThreshold;
};
/**
* Create a new empty presentation shell. Upon success, call Init
* before attempting to use the shell.
*/
nsresult
NS_NewPresShell(nsIPresShell** aInstancePtrResult);
#endif /* nsIPresShell_h___ */