gecko-dev/dom/base/nsRange.h

/* -*- 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/. */

/*
 * Implementation of the DOM nsIDOMRange object.
 */

#ifndef nsRange_h___
#define nsRange_h___

#include "nsIDOMRange.h"
#include "nsCOMPtr.h"
#include "nsINode.h"
#include "nsIDocument.h"
#include "nsIDOMNode.h"
#include "nsLayoutUtils.h"
#include "prmon.h"
#include "nsStubMutationObserver.h"
#include "nsWrapperCache.h"
#include "mozilla/Attributes.h"
#include "mozilla/GuardObjects.h"
#include "mozilla/LinkedList.h"
#include "mozilla/RangeBoundary.h"

namespace mozilla {
class ErrorResult;
namespace dom {
struct ClientRectsAndTexts;
class DocumentFragment;
class DOMRect;
class DOMRectList;
class Selection;
} // namespace dom
} // namespace mozilla

class nsRange final : public nsIDOMRange,
                      public nsStubMutationObserver,
                      public nsWrapperCache,
                      // For linking together selection-associated ranges.
                      public mozilla::LinkedListElement<nsRange>
{
  typedef mozilla::ErrorResult ErrorResult;
  typedef mozilla::dom::DOMRect DOMRect;
  typedef mozilla::dom::DOMRectList DOMRectList;
  typedef mozilla::RangeBoundary RangeBoundary;
  typedef mozilla::RawRangeBoundary RawRangeBoundary;

  virtual ~nsRange();

public:
  explicit nsRange(nsINode* aNode);

  static nsresult CreateRange(nsIDOMNode* aStartContainer,
                              uint32_t aStartOffset,
                              nsIDOMNode* aEndContainer,
                              uint32_t aEndOffset,
                              nsRange** aRange);
  static nsresult CreateRange(nsIDOMNode* aStartContainer,
                              uint32_t aStartOffset,
                              nsIDOMNode* aEndContainer,
                              uint32_t aEndOffset,
                              nsIDOMRange** aRange);
  static nsresult CreateRange(nsINode* aStartContainer,
                              uint32_t aStartOffset,
                              nsINode* aEndContainer,
                              uint32_t aEndOffset,
                              nsRange** aRange);
  static nsresult CreateRange(const RawRangeBoundary& aStart,
                              const RawRangeBoundary& aEnd,
                              nsRange** aRange);

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(nsRange, nsIDOMRange)

  nsrefcnt GetRefCount() const
  {
    return mRefCnt;
  }

  // nsIDOMRange interface
  NS_DECL_NSIDOMRANGE

  nsINode* GetRoot() const
  {
    return mRoot;
  }

  const RangeBoundary& StartRef() const
  {
    return mStart;
  }

  nsINode* GetStartContainer() const
  {
    return mStart.Container();
  }

  const RangeBoundary& EndRef() const
  {
    return mEnd;
  }

  nsINode* GetEndContainer() const
  {
    return mEnd.Container();
  }

  uint32_t StartOffset() const
  {
    return static_cast<uint32_t>(mStart.Offset());
  }

  uint32_t EndOffset() const
  {
    return static_cast<uint32_t>(mEnd.Offset());
  }

  nsIContent* GetChildAtStartOffset() const
  {
    return mStart.GetChildAtOffset();
  }

  nsIContent* GetChildAtEndOffset() const
  {
    return mEnd.GetChildAtOffset();
  }

  bool IsPositioned() const
  {
    return mIsPositioned;
  }

  void SetMaySpanAnonymousSubtrees(bool aMaySpanAnonymousSubtrees)
  {
    mMaySpanAnonymousSubtrees = aMaySpanAnonymousSubtrees;
  }

  /**
   * Return true iff this range is part of a Selection object
   * and isn't detached.
   */
  bool IsInSelection() const
  {
    return !!mSelection;
  }

  /**
   * Called when the range is added/removed from a Selection.
   */
  void SetSelection(mozilla::dom::Selection* aSelection);

  /**
   * Return true if this range was generated.
   * @see SetIsGenerated
   */
  bool IsGenerated() const
  {
    return mIsGenerated;
  }

  /**
   * Mark this range as being generated or not.
   * Currently it is used for marking ranges that are created when splitting up
   * a range to exclude a -moz-user-select:none region.
   * @see Selection::AddItem
   * @see ExcludeNonSelectableNodes
   */
  void SetIsGenerated(bool aIsGenerated)
  {
    mIsGenerated = aIsGenerated;
  }

  nsINode* GetCommonAncestor() const;
  void Reset();

  /**
   * SetStart() and SetEnd() sets start point or end point separately.
   * However, this is expensive especially when it's a range of Selection.
   * When you set both start and end of a range, you should use
   * SetStartAndEnd() instead.
   */
  nsresult SetStart(nsINode* aContainer, uint32_t aOffset);
  nsresult SetEnd(nsINode* aContainer, uint32_t aOffset);

  already_AddRefed<nsRange> CloneRange() const;

  /**
   * SetStartAndEnd() works similar to call both SetStart() and SetEnd().
   * Different from calls them separately, this does nothing if either
   * the start point or the end point is invalid point.
   * If the specified start point is after the end point, the range will be
   * collapsed at the end point.  Similarly, if they are in different root,
   * the range will be collapsed at the end point.
   */
  nsresult SetStartAndEnd(nsINode* aStartContainer, uint32_t aStartOffset,
                          nsINode* aEndContainer, uint32_t aEndOffset);
  nsresult SetStartAndEnd(const RawRangeBoundary& aStart,
                          const RawRangeBoundary& aEnd);

  /**
   * Adds all nodes between |aStartContent| and |aEndContent| to the range.
   * The start offset will be set before |aStartContent|,
   * while the end offset will be set immediately after |aEndContent|.
   *
   * Caller must guarantee both nodes are non null and
   * children of |aContainer| and that |aEndContent| is after |aStartContent|.
   */
  void
  SelectNodesInContainer(nsINode* aContainer,
                         nsIContent* aStartContent,
                         nsIContent* aEndContent);

  /**
   * CollapseTo() works similar to call both SetStart() and SetEnd() with
   * same node and offset.  This just calls SetStartAndParent() to set
   * collapsed range at aContainer and aOffset.
   */
  nsresult CollapseTo(nsINode* aContainer, uint32_t aOffset)
  {
    return SetStartAndEnd(aContainer, aOffset, aContainer, aOffset);
  }

  /**
   * Retrieves node and offset for setting start or end of a range to
   * before or after aNode.
   */
  static nsINode* GetContainerAndOffsetAfter(nsINode* aNode, uint32_t* aOffset)
  {
    MOZ_ASSERT(aNode);
    MOZ_ASSERT(aOffset);
    *aOffset = 0;
    nsINode* parentNode = aNode->GetParentNode();
    if (!parentNode) {
      return nullptr;
    }
    int32_t indexInParent = parentNode->IndexOf(aNode);
    if (NS_WARN_IF(indexInParent < 0)) {
      return nullptr;
    }
    *aOffset = static_cast<uint32_t>(indexInParent) + 1;
    return parentNode;
  }
  static nsINode* GetContainerAndOffsetBefore(nsINode* aNode, uint32_t* aOffset)
  {
    MOZ_ASSERT(aNode);
    MOZ_ASSERT(aOffset);
    *aOffset = 0;
    nsINode* parentNode = aNode->GetParentNode();
    if (!parentNode) {
      return nullptr;
    }
    int32_t indexInParent = parentNode->IndexOf(aNode);
    if (NS_WARN_IF(indexInParent < 0)) {
      return nullptr;
    }
    *aOffset = static_cast<uint32_t>(indexInParent);
    return parentNode;
  }

  NS_IMETHOD GetUsedFontFaces(nsIDOMFontFaceList** aResult);

  // nsIMutationObserver methods
  NS_DECL_NSIMUTATIONOBSERVER_CHARACTERDATACHANGED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
  NS_DECL_NSIMUTATIONOBSERVER_PARENTCHAINCHANGED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED

  // WebIDL
  static already_AddRefed<nsRange>
  Constructor(const mozilla::dom::GlobalObject& global,
              mozilla::ErrorResult& aRv);

  bool Collapsed() const
  {
    return mIsPositioned && mStart.Container() == mEnd.Container() &&
           mStart.Offset() == mEnd.Offset();
  }
  already_AddRefed<mozilla::dom::DocumentFragment>
  CreateContextualFragment(const nsAString& aString, ErrorResult& aError);
  already_AddRefed<mozilla::dom::DocumentFragment>
  CloneContents(ErrorResult& aErr);
  int16_t CompareBoundaryPoints(uint16_t aHow, nsRange& aOther,
                                ErrorResult& aErr);
  int16_t ComparePoint(nsINode& aContainer, uint32_t aOffset,
                       ErrorResult& aErr);
  void DeleteContents(ErrorResult& aRv);
  already_AddRefed<mozilla::dom::DocumentFragment>
    ExtractContents(ErrorResult& aErr);
  nsINode* GetCommonAncestorContainer(ErrorResult& aRv) const;
  nsINode* GetStartContainer(ErrorResult& aRv) const;
  uint32_t GetStartOffset(ErrorResult& aRv) const;
  nsINode* GetEndContainer(ErrorResult& aRv) const;
  uint32_t GetEndOffset(ErrorResult& aRv) const;
  void InsertNode(nsINode& aNode, ErrorResult& aErr);
  bool IntersectsNode(nsINode& aNode, ErrorResult& aRv);
  bool IsPointInRange(nsINode& aContainer, uint32_t aOffset, ErrorResult& aErr);

  // *JS() methods are mapped to Range.*() of DOM.
  // They may move focus only when the range represents normal selection.
  // These methods shouldn't be used from internal.
  void CollapseJS(bool aToStart);
  void SelectNodeJS(nsINode& aNode, ErrorResult& aErr);
  void SelectNodeContentsJS(nsINode& aNode, ErrorResult& aErr);
  void SetEndJS(nsINode& aNode, uint32_t aOffset, ErrorResult& aErr);
  void SetEndAfterJS(nsINode& aNode, ErrorResult& aErr);
  void SetEndBeforeJS(nsINode& aNode, ErrorResult& aErr);
  void SetStartJS(nsINode& aNode, uint32_t aOffset, ErrorResult& aErr);
  void SetStartAfterJS(nsINode& aNode, ErrorResult& aErr);
  void SetStartBeforeJS(nsINode& aNode, ErrorResult& aErr);

  void SurroundContents(nsINode& aNode, ErrorResult& aErr);
  already_AddRefed<DOMRect> GetBoundingClientRect(bool aClampToEdge = true,
                                                  bool aFlushLayout = true);
  already_AddRefed<DOMRectList> GetClientRects(bool aClampToEdge = true,
                                               bool aFlushLayout = true);
  void GetClientRectsAndTexts(
    mozilla::dom::ClientRectsAndTexts& aResult,
    ErrorResult& aErr);

  // Following methods should be used for internal use instead of *JS().
  void SelectNode(nsINode& aNode, ErrorResult& aErr);
  void SelectNodeContents(nsINode& aNode, ErrorResult& aErr);
  void SetEnd(nsINode& aNode, uint32_t aOffset, ErrorResult& aErr);
  void SetEndAfter(nsINode& aNode, ErrorResult& aErr);
  void SetEndBefore(nsINode& aNode, ErrorResult& aErr);
  void SetStart(nsINode& aNode, uint32_t aOffset, ErrorResult& aErr);
  void SetStartAfter(nsINode& aNode, ErrorResult& aErr);
  void SetStartBefore(nsINode& aNode, ErrorResult& aErr);

  static void GetInnerTextNoFlush(mozilla::dom::DOMString& aValue,
                                  mozilla::ErrorResult& aError,
                                  nsIContent* aStartContainer,
                                  uint32_t aStartOffset,
                                  nsIContent* aEndContainer,
                                  uint32_t aEndOffset);

  nsINode* GetParentObject() const { return mOwner; }
  virtual JSObject* WrapObject(JSContext* cx, JS::Handle<JSObject*> aGivenProto) override final;

private:
  // no copy's or assigns
  nsRange(const nsRange&);
  nsRange& operator=(const nsRange&);

  /**
   * Cut or delete the range's contents.
   *
   * @param aFragment nsIDOMDocumentFragment containing the nodes.
   *                  May be null to indicate the caller doesn't want a fragment.
   */
  nsresult CutContents(mozilla::dom::DocumentFragment** frag);

  static nsresult CloneParentsBetween(nsINode* aAncestor,
                                      nsINode* aNode,
                                      nsINode** aClosestAncestor,
                                      nsINode** aFarthestAncestor);

public:
  /**
   * Compute the root node of aNode for initializing range classes.
   * When aNode is in an anonymous subtree, this returns the shadow root or
   * binding parent.  Otherwise, the root node of the document or document
   * fragment.  If this returns nullptr, that means aNode can be neither the
   * start container nor end container of any range.
   */
  static nsINode* ComputeRootNode(nsINode* aNode)
  {
    return ComputeRootNode(aNode, false);
  }

  /**
   * Return true if aStartContainer/aStartOffset and aEndContainer/aEndOffset
   * are valid start and end points for a range.  Otherwise, return false.
   */
  static bool IsValidPoints(nsINode* aStartContainer, uint32_t aStartOffset,
                            nsINode* aEndContainer, uint32_t aEndOffset);

/******************************************************************************
 *  Utility routine to detect if a content node starts before a range and/or
 *  ends after a range.  If neither it is contained inside the range.
 *
 *  XXX - callers responsibility to ensure node in same doc as range!
 *
 *****************************************************************************/
  static nsresult CompareNodeToRange(nsINode* aNode, nsRange* aRange,
                                     bool *outNodeBefore,
                                     bool *outNodeAfter);

  /**
   * Return true if any part of (aNode, aStartOffset) .. (aNode, aEndOffset)
   * overlaps any nsRange in aNode's GetNextRangeCommonAncestor ranges (i.e.
   * where aNode is a descendant of a range's common ancestor node).
   * If a nsRange starts in (aNode, aEndOffset) or if it ends in
   * (aNode, aStartOffset) then it is non-overlapping and the result is false
   * for that nsRange.  Collapsed ranges always counts as non-overlapping.
   */
  static bool IsNodeSelected(nsINode* aNode, uint32_t aStartOffset,
                             uint32_t aEndOffset);

  /**
   * This helper function gets rects and correlated text for the given range.
   * @param aTextList optional where nullptr = don't retrieve text
   */
  static void CollectClientRectsAndText(nsLayoutUtils::RectCallback* aCollector,
                                        mozilla::dom::Sequence<nsString>* aTextList,
                                        nsRange* aRange,
                                        nsINode* aStartContainer,
                                        uint32_t aStartOffset,
                                        nsINode* aEndContainer,
                                        uint32_t aEndOffset,
                                        bool aClampToEdge, bool aFlushLayout);

  /**
   * Scan this range for -moz-user-select:none nodes and split it up into
   * multiple ranges to exclude those nodes.  The resulting ranges are put
   * in aOutRanges.  If no -moz-user-select:none node is found in the range
   * then |this| is unmodified and is the only range in aOutRanges.
   * Otherwise, |this| will be modified so that it ends before the first
   * -moz-user-select:none node and additional ranges may also be created.
   * If all nodes in the range are -moz-user-select:none then aOutRanges
   * will be empty.
   * @param aOutRanges the resulting set of ranges
   */
  void ExcludeNonSelectableNodes(nsTArray<RefPtr<nsRange>>* aOutRanges);

  typedef nsTHashtable<nsPtrHashKey<nsRange> > RangeHashTable;
protected:

  void RegisterCommonAncestor(nsINode* aNode);
  void UnregisterCommonAncestor(nsINode* aNode, bool aIsUnlinking);
  nsINode* IsValidBoundary(nsINode* aNode) const
  {
    return ComputeRootNode(aNode, mMaySpanAnonymousSubtrees);
  }

  /**
   * XXX nsRange should accept 0 - UINT32_MAX as offset.  However, users of
   *     nsRange treat offset as int32_t.  Additionally, some other internal
   *     APIs like nsINode::IndexOf() use int32_t.  Therefore, nsRange should
   *     accept only 0 - INT32_MAX as valid offset for now.
   */
  static bool IsValidOffset(uint32_t aOffset)
  {
    return aOffset <= INT32_MAX;
  }
  static bool IsValidOffset(nsINode* aNode, uint32_t aOffset);

  static nsINode* ComputeRootNode(nsINode* aNode,
                                  bool aMaySpanAnonymousSubtrees);

  // CharacterDataChanged set aNotInsertedYet to true to disable an assertion
  // and suppress re-registering a range common ancestor node since
  // the new text node of a splitText hasn't been inserted yet.
  // CharacterDataChanged does the re-registering when needed.
  void DoSetRange(const RawRangeBoundary& lowerBound,
                  const RawRangeBoundary& upperBound,
                  nsINode* aRoot, bool aNotInsertedYet = false);

  void DoSetRange(nsINode* aStartContainer, uint32_t aStartOffset,
                  nsINode* aEndContainer, uint32_t aEndOffset,
                  nsINode* aRoot, bool aNotInsertedYet = false)
  {
    RawRangeBoundary start(aStartContainer, aStartOffset);
    RawRangeBoundary end(aEndContainer, aEndOffset);

    DoSetRange(start, end, aRoot, aNotInsertedYet);
  }

  /**
   * For a range for which IsInSelection() is true, return the common ancestor
   * for the range, which we had to compute when the common ancestor changed or
   * IsInSelection became true, so we could register with it.  That is, it's a
   * faster version of GetCommonAncestor that only works for ranges in a
   * Selection.  The method will assert and the behavior is undefined if called
   * on a range where IsInSelection() is false.
   */
  nsINode* GetRegisteredCommonAncestor();

  // Helper to IsNodeSelected.
  static bool IsNodeInSortedRanges(nsINode* aNode,
                                   uint32_t aStartOffset,
                                   uint32_t aEndOffset,
                                   const nsTArray<const nsRange*>& aRanges,
                                   size_t aRangeStart,
                                   size_t aRangeEnd);

  // Assume that this is guaranteed that this is held by the caller when
  // this is used.  (Note that we cannot use AutoRestore for mCalledByJS
  // due to a bit field.)
  class MOZ_RAII AutoCalledByJSRestore final
  {
  private:
    nsRange& mRange;
    bool mOldValue;
    MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER

  public:
    explicit AutoCalledByJSRestore(nsRange& aRange
                                   MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : mRange(aRange)
      , mOldValue(aRange.mCalledByJS)
    {
      MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    }
    ~AutoCalledByJSRestore()
    {
      mRange.mCalledByJS = mOldValue;
    }
    bool SavedValue() const { return mOldValue; }
  };

  struct MOZ_STACK_CLASS AutoInvalidateSelection
  {
    explicit AutoInvalidateSelection(nsRange* aRange) : mRange(aRange)
    {
      if (!mRange->IsInSelection() || sIsNested) {
        return;
      }
      sIsNested = true;
      mCommonAncestor = mRange->GetRegisteredCommonAncestor();
    }
    ~AutoInvalidateSelection();
    nsRange* mRange;
    RefPtr<nsINode> mCommonAncestor;
    static bool sIsNested;
  };

  nsCOMPtr<nsIDocument> mOwner;
  nsCOMPtr<nsINode> mRoot;
  // mRegisteredCommonAncestor is only non-null when the range
  // IsInSelection().  It's kept alive via mStartContainer/mEndContainer,
  // because we update it any time those could become disconnected from it.
  nsINode* MOZ_NON_OWNING_REF mRegisteredCommonAncestor;
  RefPtr<mozilla::dom::Selection> mSelection;

  // These raw pointers are used to remember a child that is about
  // to be inserted between a CharacterData call and a subsequent
  // ContentInserted or ContentAppended call. It is safe to store
  // these refs because the caller is guaranteed to trigger both
  // notifications while holding a strong reference to the new child.
  nsIContent* MOZ_NON_OWNING_REF mNextStartRef;
  nsIContent* MOZ_NON_OWNING_REF mNextEndRef;

  RangeBoundary mStart;
  RangeBoundary mEnd;

  bool mIsPositioned : 1;
  bool mMaySpanAnonymousSubtrees : 1;
  bool mIsGenerated : 1;
  bool mCalledByJS : 1;
};

inline nsISupports*
ToCanonicalSupports(nsRange* aRange)
{
  return static_cast<nsIDOMRange*>(aRange);
}

inline nsISupports*
ToSupports(nsRange* aRange)
{
  return static_cast<nsIDOMRange*>(aRange);
}

#endif /* nsRange_h___ */