michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef DirectionalityUtils_h___
michael@0: #define DirectionalityUtils_h___
michael@0: 
michael@0: #include "nscore.h"
michael@0: 
michael@0: class nsIContent;
michael@0: class nsIDocument;
michael@0: class nsINode;
michael@0: class nsAString;
michael@0: class nsAttrValue;
michael@0: class nsTextNode;
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace dom {
michael@0: class Element;
michael@0: } // namespace dom
michael@0: } // namespace mozilla
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: enum Directionality {
michael@0:   eDir_NotSet,
michael@0:   eDir_RTL,
michael@0:   eDir_LTR,
michael@0:   eDir_Auto
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Set the directionality of an element according to the algorithm defined at
michael@0:  * http://www.whatwg.org/specs/web-apps/current-work/multipage/elements.html#the-directionality,
michael@0:  * not including elements with auto direction.
michael@0:  *
michael@0:  * @return the directionality that the element was set to
michael@0:  */
michael@0: Directionality RecomputeDirectionality(mozilla::dom::Element* aElement,
michael@0:                                        bool aNotify = true);
michael@0: 
michael@0: /**
michael@0:  * Set the directionality of any descendants of a node that do not themselves
michael@0:  * have a dir attribute.
michael@0:  * For performance reasons we walk down the descendant tree in the rare case
michael@0:  * of setting the dir attribute, rather than walking up the ancestor tree in
michael@0:  * the much more common case of getting the element's directionality.
michael@0:  */
michael@0: void SetDirectionalityOnDescendants(mozilla::dom::Element* aElement,
michael@0:                                     Directionality aDir,
michael@0:                                     bool aNotify = true);
michael@0: 
michael@0: /**
michael@0:  * Walk the descendants of a node in tree order and, for any text node
michael@0:  * descendant that determines the directionality of some element and is not a
michael@0:  * descendant of another descendant of the original node with dir=auto,
michael@0:  * redetermine that element's directionality
michael@0:   */
michael@0: void WalkDescendantsResetAutoDirection(mozilla::dom::Element* aElement);
michael@0: 
michael@0: /**
michael@0:  * After setting dir=auto on an element, walk its descendants in tree order.
michael@0:  * If the node doesn't have the NODE_ANCESTOR_HAS_DIR_AUTO flag, set the
michael@0:  * NODE_ANCESTOR_HAS_DIR_AUTO flag on all of its descendants.
michael@0:  * Resolve the directionality of the element by the "downward propagation
michael@0:  * algorithm" (defined in section 3 in the comments at the beginning of
michael@0:  * DirectionalityUtils.cpp)
michael@0:  */
michael@0: void WalkDescendantsSetDirAuto(mozilla::dom::Element* aElement,
michael@0:                                bool aNotify = true);
michael@0: 
michael@0: /**
michael@0:  * After unsetting dir=auto on an element, walk its descendants in tree order,
michael@0:  * skipping any that have dir=auto themselves, and unset the
michael@0:  * NODE_ANCESTOR_HAS_DIR_AUTO flag
michael@0:  */
michael@0: void WalkDescendantsClearAncestorDirAuto(mozilla::dom::Element* aElement);
michael@0: 
michael@0: /**
michael@0:  * When the contents of a text node are about to change, retrieve the current
michael@0:  * directionality of the text
michael@0:  *
michael@0:  * @return whether the text node affects the directionality of any element
michael@0:  */
michael@0: bool TextNodeWillChangeDirection(nsIContent* aTextNode, Directionality* aOldDir,
michael@0:                                  uint32_t aOffset);
michael@0: 
michael@0: /**
michael@0:  * After the contents of a text node have changed, change the directionality
michael@0:  * of any elements whose directionality is determined by that node
michael@0:  */
michael@0: void TextNodeChangedDirection(nsIContent* aTextNode, Directionality aOldDir,
michael@0:                               bool aNotify);
michael@0: 
michael@0: /**
michael@0:  * When a text node is appended to an element, find any ancestors with dir=auto
michael@0:  * whose directionality will be determined by the text node
michael@0:  */
michael@0: void SetDirectionFromNewTextNode(nsIContent* aTextNode);
michael@0: 
michael@0: /**
michael@0:  * When a text node is removed from a document, find any ancestors whose
michael@0:  * directionality it determined and redetermine their directionality
michael@0:  *
michael@0:  * @param aTextNode the text node
michael@0:  * @param aNullParent whether the the parent is also being removed
michael@0:  *        (passed from UnbindFromTree)
michael@0:  */
michael@0: void ResetDirectionSetByTextNode(nsTextNode* aTextNode, bool aNullParent);
michael@0: 
michael@0: /**
michael@0:  * Set the directionality of an element according to the directionality of the
michael@0:  * text in aValue
michael@0:  */
michael@0: void SetDirectionalityFromValue(mozilla::dom::Element* aElement,
michael@0:                                 const nsAString& aValue,
michael@0:                                 bool aNotify);
michael@0: 
michael@0: /**
michael@0:  * Called when setting the dir attribute on an element, immediately after
michael@0:  * AfterSetAttr. This is instead of using BeforeSetAttr or AfterSetAttr, because
michael@0:  * in AfterSetAttr we don't know the old value, so we can't identify all cases
michael@0:  * where we need to walk up or down the document tree and reset the direction;
michael@0:  * and in BeforeSetAttr we can't do the walk because this element hasn't had the
michael@0:  * value set yet so the results will be wrong.
michael@0:  */
michael@0: void OnSetDirAttr(mozilla::dom::Element* aElement,
michael@0:                   const nsAttrValue* aNewValue,
michael@0:                   bool hadValidDir,
michael@0:                   bool hadDirAuto,
michael@0:                   bool aNotify);
michael@0: 
michael@0: /**
michael@0:  * Called when binding a new element to the tree, to set the
michael@0:  * NodeAncestorHasDirAuto flag and set the direction of the element and its
michael@0:  * ancestors if necessary
michael@0:  */
michael@0: void SetDirOnBind(mozilla::dom::Element* aElement, nsIContent* aParent);
michael@0: 
michael@0: /**
michael@0:  * Called when unbinding an element from the tree, to recompute the
michael@0:  * directionality of the element if it doesn't have autodirection, and to
michael@0:  * clean up any entries in nsTextDirectionalityMap that refer to it.
michael@0:  */
michael@0: void ResetDir(mozilla::dom::Element* aElement);
michael@0: } // end namespace mozilla
michael@0: 
michael@0: #endif /* DirectionalityUtils_h___ */