1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/base/src/ChildIterator.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,123 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim: set ts=2 sw=2 et tw=80: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.8 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef ChildIterator_h
1.11 +#define ChildIterator_h
1.12 +
1.13 +/**
1.14 + * Iterates over the children on a node. If a child is an insertion point,
1.15 + * iterates over the children inserted there instead, or the default content
1.16 + * if no children are inserted there.
1.17 + *
1.18 + * The FlattenedChildIterator expands any anonymous content bound from an XBL
1.19 + * binding's <xbl:content> element.
1.20 + */
1.21 +
1.22 +#include "nsIContent.h"
1.23 +
1.24 +namespace mozilla {
1.25 +namespace dom {
1.26 +
1.27 +// This class iterates normal DOM child nodes of a given DOM node with
1.28 +// <xbl:children> nodes replaced by the elements that have been filtered into that
1.29 +// insertion point. Any bindings on the given element are ignored for purposes
1.30 +// of determining which insertion point children are filtered into. The iterator
1.31 +// can be initialized to start at the end by providing false for aStartAtBeginning
1.32 +// in order to start iterating in reverse from the last child.
1.33 +class ExplicitChildIterator
1.34 +{
1.35 +public:
1.36 + ExplicitChildIterator(nsIContent* aParent, bool aStartAtBeginning = true)
1.37 + : mParent(aParent),
1.38 + mChild(nullptr),
1.39 + mDefaultChild(nullptr),
1.40 + mIndexInInserted(0),
1.41 + mIsFirst(aStartAtBeginning)
1.42 + {
1.43 + }
1.44 +
1.45 + nsIContent* GetNextChild();
1.46 +
1.47 + // Looks for aChildToFind respecting insertion points until aChildToFind
1.48 + // or aBound is found. If aBound is nullptr then the seek is unbounded. Returns
1.49 + // whether aChildToFind was found as an explicit child prior to encountering
1.50 + // aBound.
1.51 + bool Seek(nsIContent* aChildToFind, nsIContent* aBound = nullptr)
1.52 + {
1.53 + // It would be nice to assert that we find aChildToFind, but bz thinks that
1.54 + // we might not find aChildToFind when called from ContentInserted
1.55 + // if first-letter frames are about.
1.56 +
1.57 + nsIContent* child;
1.58 + do {
1.59 + child = GetNextChild();
1.60 + } while (child && child != aChildToFind && child != aBound);
1.61 +
1.62 + return child == aChildToFind;
1.63 + }
1.64 +
1.65 + // Returns the current target of this iterator (which might be an explicit
1.66 + // child of the node, fallback content of an insertion point or
1.67 + // a node distributed to an insertion point.
1.68 + nsIContent* Get();
1.69 +
1.70 + // The inverse of GetNextChild. Properly steps in and out of insertion
1.71 + // points.
1.72 + nsIContent* GetPreviousChild();
1.73 +
1.74 +protected:
1.75 + // The parent of the children being iterated. For the FlattenedChildIterator,
1.76 + // if there is a binding attached to the original parent, mParent points to
1.77 + // the <xbl:content> element for the binding.
1.78 + nsIContent* mParent;
1.79 +
1.80 + // The current child. When we encounter an insertion point,
1.81 + // mChild remains as the insertion point whose content we're iterating (and
1.82 + // our state is controled by mDefaultChild or mIndexInInserted depending on
1.83 + // whether the insertion point expands to its default content or not).
1.84 + nsIContent* mChild;
1.85 +
1.86 + // If non-null, this points to the current default content for the current
1.87 + // insertion point that we're iterating (i.e. mChild, which must be an
1.88 + // nsXBLChildrenElement or HTMLContentElement). Once this transitions back
1.89 + // to null, we continue iterating at mChild's next sibling.
1.90 + nsIContent* mDefaultChild;
1.91 +
1.92 + // If non-null, this points to an iterator of the explicit children of
1.93 + // the ShadowRoot projected by the current shadow element that we're
1.94 + // iterating.
1.95 + nsAutoPtr<ExplicitChildIterator> mShadowIterator;
1.96 +
1.97 + // If not zero, we're iterating inserted children for an insertion point. This
1.98 + // is an index into mChild's inserted children array (mChild must be an
1.99 + // nsXBLChildrenElement). The index is one past the "current" child (as
1.100 + // opposed to mChild which represents the "current" child).
1.101 + uint32_t mIndexInInserted;
1.102 +
1.103 + // A flag to let us know that we haven't started iterating yet.
1.104 + bool mIsFirst;
1.105 +};
1.106 +
1.107 +// Iterates over the flattened children of a node, which accounts for anonymous
1.108 +// children and nodes moved by insertion points. If a node has anonymous
1.109 +// children, those are iterated over.
1.110 +class FlattenedChildIterator : public ExplicitChildIterator
1.111 +{
1.112 +public:
1.113 + FlattenedChildIterator(nsIContent* aParent);
1.114 +
1.115 + bool XBLInvolved() { return mXBLInvolved; }
1.116 +
1.117 +private:
1.118 + // For certain optimizations, nsCSSFrameConstructor needs to know if the
1.119 + // child list of the element that we're iterating matches its .childNodes.
1.120 + bool mXBLInvolved;
1.121 +};
1.122 +
1.123 +} // namespace dom
1.124 +} // namespace mozilla
1.125 +
1.126 +#endif
