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sousa-gecko/dom/base/DirectionalityUtils.h

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7.8 KiB
C++

/* 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/. */
#ifndef DirectionalityUtils_h_
#define DirectionalityUtils_h_
#include "mozilla/Directionality.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/HTMLSlotElement.h"
#include "mozilla/dom/Text.h"
#include "nsIContentInlines.h"
#include "nsStringFwd.h"
#include "nscore.h"
class nsIContent;
class nsINode;
class nsAttrValue;
namespace mozilla::dom {
class HTMLSlotElement;
class ShadowRoot;
struct UnbindContext;
} // namespace mozilla::dom
namespace mozilla {
inline bool MayAffectDirAutoElement(const nsINode* aNode) {
return aNode &&
(aNode->NodeOrAncestorHasDirAuto() || aNode->AffectsDirAutoSlot());
}
/**
* If dir!=ltr we can't anymore assume all elements in this document are LTR.
*/
inline void MaybeSetDocNeedsDirHandling(dom::Element* aElement,
const nsAttrValue* aValue) {
if (aValue && aValue->Type() == nsAttrValue::eEnum &&
Directionality(aValue->GetEnumValue()) != Directionality::Ltr) {
// nsINode::CloneAndAdopt sets the flag when adopting to another document.
aElement->OwnerDoc()->SetNeedsDirHandling();
}
}
/**
* Various methods for returning the directionality of a string using the
* first-strong algorithm defined in http://unicode.org/reports/tr9/#P2
*
* @param[out] aFirstStrong the offset to the first character in the string with
* strong directionality, or UINT32_MAX if there is none (in which
* case the return value is Directionality::Unset).
* @return the directionality of the string, or Unset if not available.
*/
Directionality GetDirectionFromText(const char16_t* aText,
const uint32_t aLength,
uint32_t* aFirstStrong = nullptr);
/**
* Set the directionality of an element according to the algorithm defined at
* https://html.spec.whatwg.org/#the-directionality, not including elements with
* auto direction.
*
* @return the directionality that the element was set to
*/
Directionality RecomputeDirectionality(mozilla::dom::Element* aElement,
bool aNotify = true);
/**
* Set the directionality of any descendants of a node that do not themselves
* have a dir attribute.
* For performance reasons we walk down the descendant tree in the rare case
* of setting the dir attribute, rather than walking up the ancestor tree in
* the much more common case of getting the element's directionality.
*/
void SetDirectionalityOnDescendants(mozilla::dom::Element* aElement,
Directionality aDir, bool aNotify = true);
/**
* Update flags on assigned node and auto directionality of the slot.
*/
void SlotAssignedNodeAddedForDir(dom::HTMLSlotElement* aSlot,
nsIContent& aAssignedNode);
/**
* Update flags on assigned node and auto directionality of the slot.
*/
void SlotAssignedNodeRemovedForDir(dom::HTMLSlotElement* aSlot,
nsIContent& aUnassignedNode);
bool TextNodeWillChangeDirectionInternal(dom::Text*, Directionality*, uint32_t);
/**
* When the contents of a text node are about to change, retrieve the current
* directionality of the text
*
* @return whether the text node affects the directionality of any element
*/
inline bool TextNodeWillChangeDirection(dom::Text* aTextNode,
Directionality* aOldDir,
uint32_t aOffset) {
if (!MayAffectDirAutoElement(aTextNode)) {
return false;
}
return TextNodeWillChangeDirectionInternal(aTextNode, aOldDir, aOffset);
}
/**
* After the contents of a text node have changed, change the directionality
* of any elements whose directionality is determined by that node
*/
void TextNodeChangedDirection(dom::Text* aTextNode, Directionality aOldDir,
bool aNotify);
void SetDirectionFromNewTextNodeInternal(dom::Text*, nsINode*);
/**
* When a text node is appended to an element, find any ancestors with dir=auto
* whose directionality will be determined by the text node
*/
inline void SetDirectionFromNewTextNode(dom::Text* aTextNode,
nsINode* aParent) {
if (MayAffectDirAutoElement(aParent)) {
SetDirectionFromNewTextNodeInternal(aTextNode, aParent);
}
}
void ResetDirectionSetByTextNodeInternal(dom::Text*, dom::UnbindContext&);
/**
* When a text node is removed from a document, find any ancestors whose
* directionality it determined and redetermine their directionality
*/
inline void ResetDirectionSetByTextNode(dom::Text* aTextNode,
dom::UnbindContext& aContext) {
if (aTextNode->MaySetDirAuto()) {
ResetDirectionSetByTextNodeInternal(aTextNode, aContext);
}
}
void ResetDirectionSetBySlotHostInternal(dom::HTMLSlotElement*,
dom::UnbindContext&, dom::ShadowRoot*);
/**
* Similar to text nodes, slots can also determine the directionality of
* ancestors. These need to be updated if the slot is removed.
* https://html.spec.whatwg.org/#contained-text-auto-directionality
*/
inline void ResetDirectionSetBySlotHost(dom::HTMLSlotElement* aSlot,
dom::UnbindContext& aContext,
dom::ShadowRoot* aOldContainingShadow) {
if (MayAffectDirAutoElement(aSlot)) {
ResetDirectionSetBySlotHostInternal(aSlot, aContext, aOldContainingShadow);
}
}
void ResetDirFormAssociatedElementInternal(dom::Element*, bool, bool,
const nsAString*);
/**
* Update directionality of this and other affected elements.
*/
inline void ResetDirFormAssociatedElement(
mozilla::dom::Element* aElement, bool aNotify, bool aHasDirAuto,
const nsAString* aKnownValue = nullptr) {
if (aElement->OwnerDoc()->NeedsDirHandling()) {
ResetDirFormAssociatedElementInternal(aElement, aNotify, aHasDirAuto,
aKnownValue);
}
}
/**
* Called when setting the dir attribute on an element, immediately after
* AfterSetAttr. This is instead of using BeforeSetAttr or AfterSetAttr, because
* in AfterSetAttr we don't know the old value, so we can't identify all cases
* where we need to walk up or down the document tree and reset the direction;
* and in BeforeSetAttr we can't do the walk because this element hasn't had the
* value set yet so the results will be wrong.
*/
void OnSetDirAttr(mozilla::dom::Element* aElement, const nsAttrValue* aNewValue,
bool hadValidDir, bool hadDirAuto, bool aNotify);
void SetDirOnBindInternal(dom::Element*, nsIContent*);
/**
* Called when binding a new element to the tree, to set the
* NodeAncestorHasDirAuto flag and set the direction of the element and its
* ancestors if necessary
*/
inline void SetDirOnBind(mozilla::dom::Element* aElement, nsIContent* aParent) {
if (!aElement->OwnerDoc()->NeedsDirHandling()) {
MOZ_ASSERT(!aElement->State().HasAtLeastOneOfStates(
dom::ElementState::HAS_DIR_ATTR_RTL |
dom::ElementState::HAS_DIR_ATTR_LIKE_AUTO));
aElement->SetDirectionality(Directionality::Ltr, false);
return;
}
SetDirOnBindInternal(aElement, aParent);
}
/**
* Called when unbinding an element from the tree, to recompute the
* directionality of the element if it doesn't have autodirection, and to
* clean up any entries in nsTextDirectionalityMap that refer to it.
*/
inline void ResetDir(mozilla::dom::Element* aElement) {
if (aElement->OwnerDoc()->NeedsDirHandling() && !aElement->HasDirAuto()) {
RecomputeDirectionality(aElement, false);
}
}
} // end namespace mozilla
#endif /* DirectionalityUtils_h_ */