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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 nsFrameList_h___
#define nsFrameList_h___
#include <stdio.h> /* for FILE* */
#include "nsDebug.h"
#include "nsTArray.h"
#include "mozilla/FunctionTypeTraits.h"
#include "mozilla/RefPtr.h"
#include "mozilla/ReverseIterator.h"
#if defined(DEBUG) || defined(MOZ_DUMP_PAINTING) || defined(MOZ_LAYOUT_DEBUGGER)
// DEBUG_FRAME_DUMP enables nsIFrame::List and related methods.
// You can also define this in a non-DEBUG build if you need frame dumps.
# define DEBUG_FRAME_DUMP 1
#endif
class nsContainerFrame;
class nsIContent;
class nsIFrame;
class nsPresContext;
namespace mozilla {
class PresShell;
namespace layout {
class FrameChildList;
enum FrameChildListID {
// The individual concrete child lists.
kPrincipalList,
kPopupList,
kCaptionList,
kColGroupList,
kSelectPopupList,
kAbsoluteList,
kFixedList,
kOverflowList,
kOverflowContainersList,
kExcessOverflowContainersList,
kOverflowOutOfFlowList,
kFloatList,
kBulletList,
kPushedFloatsList,
kBackdropList,
// A special alias for kPrincipalList that suppress the reflow request that
// is normally done when manipulating child lists.
kNoReflowPrincipalList,
};
// A helper class for nsIFrame::Destroy[From]. It's defined here because
// nsFrameList needs it and we can't use nsIFrame here.
struct PostFrameDestroyData {
PostFrameDestroyData(const PostFrameDestroyData&) = delete;
PostFrameDestroyData() = default;
AutoTArray<RefPtr<nsIContent>, 100> mAnonymousContent;
void AddAnonymousContent(already_AddRefed<nsIContent>&& aContent) {
mAnonymousContent.AppendElement(aContent);
}
};
} // namespace layout
} // namespace mozilla
// Uncomment this to enable expensive frame-list integrity checking
// #define DEBUG_FRAME_LIST
/**
* A class for managing a list of frames.
*/
class nsFrameList {
public:
nsFrameList() : mFirstChild(nullptr), mLastChild(nullptr) {}
nsFrameList(nsIFrame* aFirstFrame, nsIFrame* aLastFrame)
: mFirstChild(aFirstFrame), mLastChild(aLastFrame) {
VerifyList();
}
// XXX: Ideally, copy constructor should be removed because a frame should be
// owned by one list.
nsFrameList(const nsFrameList& aOther) = default;
// XXX: ideally, copy assignment should be removed because we should use move
// assignment to transfer the ownership.
nsFrameList& operator=(const nsFrameList& aOther) = default;
/**
* Move the frames in aOther to this list. aOther becomes empty after this
* operation.
*/
nsFrameList(nsFrameList&& aOther)
: mFirstChild(aOther.mFirstChild), mLastChild(aOther.mLastChild) {
aOther.Clear();
VerifyList();
}
nsFrameList& operator=(nsFrameList&& aOther) {
SetFrames(aOther);
return *this;
}
/**
* Infallibly allocate a nsFrameList from the shell arena.
*/
void* operator new(size_t sz, mozilla::PresShell* aPresShell);
/**
* Deallocate this list that was allocated from the shell arena.
* The list is required to be empty.
*/
void Delete(mozilla::PresShell* aPresShell);
/**
* For each frame in this list: remove it from the list then call
* Destroy() on it.
*/
void DestroyFrames();
/**
* For each frame in this list: remove it from the list then call
* DestroyFrom(aDestructRoot, aPostDestroyData) on it.
*/
void DestroyFramesFrom(
nsIFrame* aDestructRoot,
mozilla::layout::PostFrameDestroyData& aPostDestroyData);
void Clear() { mFirstChild = mLastChild = nullptr; }
void SetFrames(nsIFrame* aFrameList);
void SetFrames(nsFrameList& aFrameList) {
MOZ_ASSERT(!mFirstChild, "Losing frames");
mFirstChild = aFrameList.FirstChild();
mLastChild = aFrameList.LastChild();
aFrameList.Clear();
}
class Slice;
/**
* Append aFrameList to this list. If aParent is not null,
* reparents the newly added frames. Clears out aFrameList and
* returns a list slice represening the newly-appended frames.
*/
Slice AppendFrames(nsContainerFrame* aParent, nsFrameList& aFrameList) {
return InsertFrames(aParent, LastChild(), aFrameList);
}
/**
* Append aFrame to this list. If aParent is not null,
* reparents the newly added frame.
*/
void AppendFrame(nsContainerFrame* aParent, nsIFrame* aFrame) {
nsFrameList temp(aFrame, aFrame);
AppendFrames(aParent, temp);
}
/**
* Take aFrame out of the frame list. This also disconnects aFrame
* from the sibling list. The frame must be non-null and present on
* this list.
*/
void RemoveFrame(nsIFrame* aFrame);
/**
* Take the frames after aAfterFrame out of the frame list. If
* aAfterFrame is null, removes the entire list.
* @param aAfterFrame a frame in this list, or null
* @return the removed frames, if any
*/
nsFrameList RemoveFramesAfter(nsIFrame* aAfterFrame);
/**
* Take the first frame (if any) out of the frame list.
* @return the first child, or nullptr if the list is empty
*/
nsIFrame* RemoveFirstChild();
/**
* The following two functions are intended to be used in concert for
* removing a frame from its frame list when the set of possible frame
* lists is known in advance, but the exact frame list is unknown.
* aFrame must be non-null.
* Example use:
* bool removed = frameList1.StartRemoveFrame(aFrame) ||
* frameList2.ContinueRemoveFrame(aFrame) ||
* frameList3.ContinueRemoveFrame(aFrame);
* MOZ_ASSERT(removed);
*
* @note One of the frame lists MUST contain aFrame, if it's on some other
* frame list then the example above will likely lead to crashes.
* This function is O(1).
* @return true iff aFrame was removed from /some/ list, not necessarily
* this one. If it was removed from a different list then it is
* guaranteed that that list is still non-empty.
* (this method is implemented in nsIFrame.h to be able to inline)
*/
inline bool StartRemoveFrame(nsIFrame* aFrame);
/**
* Precondition: StartRemoveFrame MUST be called before this.
* This function is O(1).
* @see StartRemoveFrame
* @return true iff aFrame was removed from this list
* (this method is implemented in nsIFrame.h to be able to inline)
*/
inline bool ContinueRemoveFrame(nsIFrame* aFrame);
/**
* Take aFrame out of the frame list and then destroy it.
* The frame must be non-null and present on this list.
*/
void DestroyFrame(nsIFrame* aFrame);
/**
* Insert aFrame right after aPrevSibling, or prepend it to this
* list if aPrevSibling is null. If aParent is not null, also
* reparents newly-added frame. Note that this method always
* sets the frame's nextSibling pointer.
*/
void InsertFrame(nsContainerFrame* aParent, nsIFrame* aPrevSibling,
nsIFrame* aFrame) {
nsFrameList temp(aFrame, aFrame);
InsertFrames(aParent, aPrevSibling, temp);
}
/**
* Inserts aFrameList into this list after aPrevSibling (at the beginning if
* aPrevSibling is null). If aParent is not null, reparents the newly added
* frames. Clears out aFrameList and returns a list slice representing the
* newly-inserted frames.
*/
Slice InsertFrames(nsContainerFrame* aParent, nsIFrame* aPrevSibling,
nsFrameList& aFrameList);
class FrameLinkEnumerator;
/**
* Split this list just before the first frame that matches aPredicate,
* and return a nsFrameList containing all the frames before it. The
* matched frame and all frames after it stay in this list. If no matched
* frame exists, all the frames are drained into the returned list, and
* this list ends up empty.
*
* aPredicate should be of this function signature: bool(nsIFrame*).
*/
template <typename Predicate>
nsFrameList Split(Predicate&& aPredicate) {
static_assert(
std::is_same<
typename mozilla::FunctionTypeTraits<Predicate>::ReturnType,
bool>::value &&
mozilla::FunctionTypeTraits<Predicate>::arity == 1 &&
std::is_same<typename mozilla::FunctionTypeTraits<
Predicate>::template ParameterType<0>,
nsIFrame*>::value,
"aPredicate should be of this function signature: bool(nsIFrame*)");
FrameLinkEnumerator link(*this);
link.Find(aPredicate);
return ExtractHead(link);
}
/**
* Split this frame list such that all the frames before the link pointed to
* by aLink end up in the returned list, while the remaining frames stay in
* this list. After this call, aLink points to the beginning of this list.
*/
nsFrameList ExtractHead(FrameLinkEnumerator& aLink);
/**
* Split this frame list such that all the frames coming after the link
* pointed to by aLink end up in the returned list, while the frames before
* that link stay in this list. After this call, aLink is at end.
*/
nsFrameList ExtractTail(FrameLinkEnumerator& aLink);
nsIFrame* FirstChild() const { return mFirstChild; }
nsIFrame* LastChild() const { return mLastChild; }
nsIFrame* FrameAt(int32_t aIndex) const;
int32_t IndexOf(nsIFrame* aFrame) const;
bool IsEmpty() const { return nullptr == mFirstChild; }
bool NotEmpty() const { return nullptr != mFirstChild; }
/**
* Return true if aFrame is on this list.
* @note this method has O(n) time complexity over the length of the list
* XXXmats: ideally, we should make this function #ifdef DEBUG
*/
bool ContainsFrame(const nsIFrame* aFrame) const;
/**
* Get the number of frames in this list. Note that currently the
* implementation has O(n) time complexity. Do not call it repeatedly in hot
* code.
* XXXmats: ideally, we should make this function #ifdef DEBUG
*/
int32_t GetLength() const;
/**
* If this frame list has only one frame, return that frame.
* Otherwise, return null.
*/
nsIFrame* OnlyChild() const {
if (FirstChild() == LastChild()) {
return FirstChild();
}
return nullptr;
}
/**
* Call SetParent(aParent) for each frame in this list.
* @param aParent the new parent frame, must be non-null
*/
void ApplySetParent(nsContainerFrame* aParent) const;
/**
* If this frame list is non-empty then append it to aLists as the
* aListID child list.
* (this method is implemented in FrameChildList.h for dependency reasons)
*/
inline void AppendIfNonempty(
nsTArray<mozilla::layout::FrameChildList>* aLists,
mozilla::layout::FrameChildListID aListID) const;
/**
* Return the frame before this frame in visual order (after Bidi reordering).
* If aFrame is null, return the last frame in visual order.
*/
nsIFrame* GetPrevVisualFor(nsIFrame* aFrame) const;
/**
* Return the frame after this frame in visual order (after Bidi reordering).
* If aFrame is null, return the first frame in visual order.
*/
nsIFrame* GetNextVisualFor(nsIFrame* aFrame) const;
#ifdef DEBUG_FRAME_DUMP
void List(FILE* out) const;
#endif
static inline const nsFrameList& EmptyList();
class Enumerator;
/**
* A class representing a slice of a frame list.
*/
class Slice {
friend class Enumerator;
public:
// Implicit on purpose, so that we can easily create enumerators from
// nsFrameList via this impicit constructor.
MOZ_IMPLICIT Slice(const nsFrameList& aList)
:
#ifdef DEBUG
mList(aList),
#endif
mStart(aList.FirstChild()),
mEnd(nullptr) {
}
Slice(const nsFrameList& aList, nsIFrame* aStart, nsIFrame* aEnd)
:
#ifdef DEBUG
mList(aList),
#endif
mStart(aStart),
mEnd(aEnd) {
}
Slice(const Slice& aOther) = default;
private:
#ifdef DEBUG
const nsFrameList& mList;
#endif
nsIFrame* const mStart; // our starting frame
const nsIFrame* const mEnd; // The first frame that is NOT in the slice.
// May be null.
};
class Enumerator {
public:
explicit Enumerator(const Slice& aSlice)
:
#ifdef DEBUG
mSlice(aSlice),
#endif
mFrame(aSlice.mStart),
mEnd(aSlice.mEnd) {
}
Enumerator(const Enumerator& aOther) = default;
bool AtEnd() const {
// Can't just check mEnd, because some table code goes and destroys the
// tail of the frame list (including mEnd!) while iterating over the
// frame list.
return !mFrame || mFrame == mEnd;
}
/* Next() needs to know about nsIFrame, and nsIFrame will need to
know about nsFrameList methods, so in order to inline this put
the implementation in nsIFrame.h */
inline void Next();
/**
* Get the current frame we're pointing to. Do not call this on an
* iterator that is at end!
*/
nsIFrame* get() const {
MOZ_ASSERT(!AtEnd(), "Enumerator is at end");
return mFrame;
}
/**
* Get an enumerator that is just like this one, but not limited in terms of
* the part of the list it will traverse.
*/
Enumerator GetUnlimitedEnumerator() const {
return Enumerator(*this, nullptr);
}
#ifdef DEBUG
const nsFrameList& List() const { return mSlice.mList; }
#endif
protected:
Enumerator(const Enumerator& aOther, const nsIFrame* const aNewEnd)
:
#ifdef DEBUG
mSlice(aOther.mSlice),
#endif
mFrame(aOther.mFrame),
mEnd(aNewEnd) {
}
#ifdef DEBUG
/* Has to be an object, not a reference, since the slice could
well be a temporary constructed from an nsFrameList */
const Slice mSlice;
#endif
nsIFrame* mFrame; // our current frame.
const nsIFrame* const mEnd; // The first frame we should NOT enumerate.
// May be null.
};
/**
* A class that can be used to enumerate links between frames. When created
* from an nsFrameList, it points to the "link" immediately before the first
* frame. It can then be advanced until it points to the "link" immediately
* after the last frame. At any position, PrevFrame() and NextFrame() are
* the frames before and after the given link. This means PrevFrame() is
* null when the enumerator is at the beginning of the list and NextFrame()
* is null when it's AtEnd().
*/
class FrameLinkEnumerator : private Enumerator {
public:
friend class nsFrameList;
explicit FrameLinkEnumerator(const nsFrameList& aList)
: Enumerator(aList), mPrev(nullptr) {}
FrameLinkEnumerator(const FrameLinkEnumerator& aOther) = default;
/* This constructor needs to know about nsIFrame, and nsIFrame will need to
know about nsFrameList methods, so in order to inline this put
the implementation in nsIFrame.h */
inline FrameLinkEnumerator(const nsFrameList& aList, nsIFrame* aPrevFrame);
void operator=(const FrameLinkEnumerator& aOther) {
MOZ_ASSERT(&List() == &aOther.List(), "Different lists?");
mFrame = aOther.mFrame;
mPrev = aOther.mPrev;
}
inline void Next();
/**
* Find the first frame from the current position that satisfies
* aPredicate, and stop at it. If no such frame exists, then this method
* advances to the end of the list.
*
* aPredicate should be of this function signature: bool(nsIFrame*).
*
* Note: Find() needs to see the definition of Next(), so put this
* definition in nsIFrame.h.
*/
template <typename Predicate>
inline void Find(Predicate&& aPredicate);
bool AtEnd() const { return Enumerator::AtEnd(); }
nsIFrame* PrevFrame() const { return mPrev; }
nsIFrame* NextFrame() const { return mFrame; }
protected:
nsIFrame* mPrev;
};
class Iterator {
public:
// It is disputable whether these type definitions are correct, since
// operator* doesn't return a reference at all. Also, the iterator_category
// can be at most std::input_iterator_tag (rather than
// std::bidrectional_iterator_tag, as it might seem), because it is a
// stashing iterator. See also, e.g.,
using value_type = nsIFrame* const;
using pointer = value_type*;
using reference = value_type&;
using difference_type = ptrdiff_t;
using iterator_category = std::input_iterator_tag;
Iterator(const nsFrameList& aList, nsIFrame* aCurrent)
: mList(aList), mCurrent(aCurrent) {}
Iterator(const Iterator& aOther) = default;
nsIFrame* operator*() const { return mCurrent; }
// The operators need to know about nsIFrame, hence the
// implementations are in nsIFrame.h
Iterator& operator++();
Iterator& operator--();
Iterator operator++(int) {
auto ret = *this;
++*this;
return ret;
}
Iterator operator--(int) {
auto ret = *this;
--*this;
return ret;
}
friend bool operator==(const Iterator& aIter1, const Iterator& aIter2);
friend bool operator!=(const Iterator& aIter1, const Iterator& aIter2);
private:
const nsFrameList& mList;
nsIFrame* mCurrent;
};
typedef Iterator iterator;
typedef Iterator const_iterator;
typedef mozilla::ReverseIterator<Iterator> reverse_iterator;
typedef mozilla::ReverseIterator<Iterator> const_reverse_iterator;
iterator begin() const { return iterator(*this, mFirstChild); }
const_iterator cbegin() const { return begin(); }
iterator end() const { return iterator(*this, nullptr); }
const_iterator cend() const { return end(); }
reverse_iterator rbegin() const { return reverse_iterator(end()); }
const_reverse_iterator crbegin() const { return rbegin(); }
reverse_iterator rend() const { return reverse_iterator(begin()); }
const_reverse_iterator crend() const { return rend(); }
private:
void operator delete(void*) = delete;
#ifdef DEBUG_FRAME_LIST
void VerifyList() const;
#else
void VerifyList() const {}
#endif
protected:
/**
* Disconnect aFrame from its siblings. This must only be called if aFrame
* is NOT the first or last sibling, because otherwise its nsFrameList will
* have a stale mFirst/LastChild pointer. This precondition is asserted.
* This function is O(1).
*/
static void UnhookFrameFromSiblings(nsIFrame* aFrame);
nsIFrame* mFirstChild;
nsIFrame* mLastChild;
};
inline bool operator==(const nsFrameList::Iterator& aIter1,
const nsFrameList::Iterator& aIter2) {
MOZ_ASSERT(&aIter1.mList == &aIter2.mList,
"must not compare iterator from different list");
return aIter1.mCurrent == aIter2.mCurrent;
}
inline bool operator!=(const nsFrameList::Iterator& aIter1,
const nsFrameList::Iterator& aIter2) {
MOZ_ASSERT(&aIter1.mList == &aIter2.mList,
"Must not compare iterator from different list");
return aIter1.mCurrent != aIter2.mCurrent;
}
namespace mozilla {
/**
* Simple "auto_ptr" for nsFrameLists allocated from the shell arena.
* The frame list given to the constructor will be deallocated (if non-null)
* in the destructor. The frame list must then be empty.
*/
class MOZ_RAII AutoFrameListPtr final {
public:
AutoFrameListPtr(nsPresContext* aPresContext, nsFrameList* aFrameList)
: mPresContext(aPresContext), mFrameList(aFrameList) {}
~AutoFrameListPtr();
operator nsFrameList*() const { return mFrameList; }
nsFrameList* operator->() const { return mFrameList; }
private:
nsPresContext* mPresContext;
nsFrameList* mFrameList;
};
namespace layout::detail {
union AlignedFrameListBytes {
void* ptr;
char bytes[sizeof(nsFrameList)];
};
extern const AlignedFrameListBytes gEmptyFrameListBytes;
} // namespace layout::detail
} // namespace mozilla
/* static */ inline const nsFrameList& nsFrameList::EmptyList() {
return *reinterpret_cast<const nsFrameList*>(
&mozilla::layout::detail::gEmptyFrameListBytes);
}
#endif /* nsFrameList_h___ */