root/Source/core/dom/Text.cpp

DEFINITIONS

1. create
2. createEditingText
3. mergeNextSiblingNodesIfPossible
4. splitText
5. earliestLogicallyAdjacentTextNode
6. latestLogicallyAdjacentTextNode
7. wholeText
8. replaceWholeText
9. nodeName
10. nodeType
11. cloneNode
12. textRendererIsNeeded
13. isSVGText
14. createTextRenderer
15. attach
16. recalcTextStyle
17. needsWhitespaceRenderer
18. updateTextRenderer
19. cloneWithData
20. formatForDebugger

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "core/dom/Text.h"

#include "SVGNames.h"
#include "bindings/v8/ExceptionState.h"
#include "bindings/v8/ExceptionStatePlaceholder.h"
#include "core/css/resolver/StyleResolver.h"
#include "core/dom/ExceptionCode.h"
#include "core/dom/NodeRenderStyle.h"
#include "core/dom/NodeRenderingTraversal.h"
#include "core/dom/NodeTraversal.h"
#include "core/dom/RenderTreeBuilder.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/events/ScopedEventQueue.h"
#include "core/rendering/RenderCombineText.h"
#include "core/rendering/RenderText.h"
#include "core/rendering/svg/RenderSVGInlineText.h"
#include "core/svg/SVGForeignObjectElement.h"
#include "wtf/text/CString.h"
#include "wtf/text/StringBuilder.h"

using namespace std;

namespace WebCore {

PassRefPtr<Text> Text::create(Document& document, const String& data)
{
    return adoptRef(new Text(document, data, CreateText));
}

PassRefPtr<Text> Text::createEditingText(Document& document, const String& data)
{
    return adoptRef(new Text(document, data, CreateEditingText));
}

PassRefPtr<Node> Text::mergeNextSiblingNodesIfPossible()
{
    RefPtr<Node> protect(this);

    // Remove empty text nodes.
    if (!length()) {
        // Care must be taken to get the next node before removing the current node.
        RefPtr<Node> nextNode(NodeTraversal::nextPostOrder(*this));
        remove(IGNORE_EXCEPTION);
        return nextNode.release();
    }

    // Merge text nodes.
    while (Node* nextSibling = this->nextSibling()) {
        if (nextSibling->nodeType() != TEXT_NODE)
            break;

        RefPtr<Text> nextText = toText(nextSibling);

        // Remove empty text nodes.
        if (!nextText->length()) {
            nextText->remove(IGNORE_EXCEPTION);
            continue;
        }

        // Both non-empty text nodes. Merge them.
        unsigned offset = length();
        String nextTextData = nextText->data();
        String oldTextData = data();
        setDataWithoutUpdate(data() + nextTextData);
        updateTextRenderer(oldTextData.length(), 0);

        // Empty nextText for layout update.
        nextText->setDataWithoutUpdate(emptyString());
        nextText->updateTextRenderer(0, nextTextData.length());

        document().didMergeTextNodes(*nextText, offset);

        // Restore nextText for mutation event.
        nextText->setDataWithoutUpdate(nextTextData);
        nextText->updateTextRenderer(0, 0);

        document().incDOMTreeVersion();
        didModifyData(oldTextData);
        nextText->remove(IGNORE_EXCEPTION);
    }

    return NodeTraversal::nextPostOrder(*this);
}

PassRefPtr<Text> Text::splitText(unsigned offset, ExceptionState& exceptionState)
{
    // IndexSizeError: Raised if the specified offset is negative or greater than
    // the number of 16-bit units in data.
    if (offset > length()) {
        exceptionState.throwDOMException(IndexSizeError, "The offset " + String::number(offset) + " is larger than the Text node's length.");
        return nullptr;
    }

    EventQueueScope scope;
    String oldStr = data();
    RefPtr<Text> newText = cloneWithData(oldStr.substring(offset));
    setDataWithoutUpdate(oldStr.substring(0, offset));

    didModifyData(oldStr);

    if (parentNode())
        parentNode()->insertBefore(newText.get(), nextSibling(), exceptionState);
    if (exceptionState.hadException())
        return nullptr;

    if (renderer())
        toRenderText(renderer())->setTextWithOffset(dataImpl(), 0, oldStr.length());

    if (parentNode())
        document().didSplitTextNode(*this);

    return newText.release();
}

static const Text* earliestLogicallyAdjacentTextNode(const Text* t)
{
    const Node* n = t;
    while ((n = n->previousSibling())) {
        Node::NodeType type = n->nodeType();
        if (type == Node::TEXT_NODE || type == Node::CDATA_SECTION_NODE) {
            t = toText(n);
            continue;
        }

        break;
    }
    return t;
}

static const Text* latestLogicallyAdjacentTextNode(const Text* t)
{
    const Node* n = t;
    while ((n = n->nextSibling())) {
        Node::NodeType type = n->nodeType();
        if (type == Node::TEXT_NODE || type == Node::CDATA_SECTION_NODE) {
            t = toText(n);
            continue;
        }

        break;
    }
    return t;
}

String Text::wholeText() const
{
    const Text* startText = earliestLogicallyAdjacentTextNode(this);
    const Text* endText = latestLogicallyAdjacentTextNode(this);

    Node* onePastEndText = endText->nextSibling();
    unsigned resultLength = 0;
    for (const Node* n = startText; n != onePastEndText; n = n->nextSibling()) {
        if (!n->isTextNode())
            continue;
        const String& data = toText(n)->data();
        if (std::numeric_limits<unsigned>::max() - data.length() < resultLength)
            CRASH();
        resultLength += data.length();
    }
    StringBuilder result;
    result.reserveCapacity(resultLength);
    for (const Node* n = startText; n != onePastEndText; n = n->nextSibling()) {
        if (!n->isTextNode())
            continue;
        result.append(toText(n)->data());
    }
    ASSERT(result.length() == resultLength);

    return result.toString();
}

PassRefPtr<Text> Text::replaceWholeText(const String& newText)
{
    // Remove all adjacent text nodes, and replace the contents of this one.

    // Protect startText and endText against mutation event handlers removing the last ref
    RefPtr<Text> startText = const_cast<Text*>(earliestLogicallyAdjacentTextNode(this));
    RefPtr<Text> endText = const_cast<Text*>(latestLogicallyAdjacentTextNode(this));

    RefPtr<Text> protectedThis(this); // Mutation event handlers could cause our last ref to go away
    RefPtr<ContainerNode> parent = parentNode(); // Protect against mutation handlers moving this node during traversal
    for (RefPtr<Node> n = startText; n && n != this && n->isTextNode() && n->parentNode() == parent;) {
        RefPtr<Node> nodeToRemove(n.release());
        n = nodeToRemove->nextSibling();
        parent->removeChild(nodeToRemove.get(), IGNORE_EXCEPTION);
    }

    if (this != endText) {
        Node* onePastEndText = endText->nextSibling();
        for (RefPtr<Node> n = nextSibling(); n && n != onePastEndText && n->isTextNode() && n->parentNode() == parent;) {
            RefPtr<Node> nodeToRemove(n.release());
            n = nodeToRemove->nextSibling();
            parent->removeChild(nodeToRemove.get(), IGNORE_EXCEPTION);
        }
    }

    if (newText.isEmpty()) {
        if (parent && parentNode() == parent)
            parent->removeChild(this, IGNORE_EXCEPTION);
        return nullptr;
    }

    setData(newText);
    return protectedThis.release();
}

String Text::nodeName() const
{
    return "#text";
}

Node::NodeType Text::nodeType() const
{
    return TEXT_NODE;
}

PassRefPtr<Node> Text::cloneNode(bool /*deep*/)
{
    return cloneWithData(data());
}

bool Text::textRendererIsNeeded(const RenderStyle& style, const RenderObject& parent)
{
    if (isEditingText())
        return true;

    if (!length())
        return false;

    if (style.display() == NONE)
        return false;

    if (!containsOnlyWhitespace())
        return true;

    if (!parent.canHaveWhitespaceChildren())
        return false;

    if (style.preserveNewline()) // pre/pre-wrap/pre-line always make renderers.
        return true;

    const RenderObject* prev = NodeRenderingTraversal::previousSiblingRenderer(this);
    if (prev && prev->isBR()) // <span><br/> <br/></span>
        return false;

    if (parent.isRenderInline()) {
        // <span><div/> <div/></span>
        if (prev && !prev->isInline())
            return false;
    } else {
        if (parent.isRenderBlock() && !parent.childrenInline() && (!prev || !prev->isInline()))
            return false;

        // Avoiding creation of a Renderer for the text node is a non-essential memory optimization.
        // So to avoid blowing up on very wide DOMs, we limit the number of siblings to visit.
        unsigned maxSiblingsToVisit = 50;

        RenderObject* first = parent.firstChild();
        while (first && first->isFloatingOrOutOfFlowPositioned() && maxSiblingsToVisit--)
            first = first->nextSibling();
        if (!first || NodeRenderingTraversal::nextSiblingRenderer(this) == first)
            // Whitespace at the start of a block just goes away.  Don't even
            // make a render object for this text.
            return false;
    }
    return true;
}

static bool isSVGText(Text* text)
{
    Node* parentOrShadowHostNode = text->parentOrShadowHostNode();
    ASSERT(parentOrShadowHostNode);
    return parentOrShadowHostNode->isSVGElement() && !isSVGForeignObjectElement(*parentOrShadowHostNode);
}

RenderText* Text::createTextRenderer(RenderStyle* style)
{
    if (isSVGText(this))
        return new RenderSVGInlineText(this, dataImpl());

    if (style->hasTextCombine())
        return new RenderCombineText(this, dataImpl());

    return new RenderText(this, dataImpl());
}

void Text::attach(const AttachContext& context)
{
    RenderTreeBuilder(this, context.resolvedStyle).createRendererForTextIfNeeded();
    CharacterData::attach(context);
}

void Text::recalcTextStyle(StyleRecalcChange change, Text* nextTextSibling)
{
    if (RenderText* renderer = toRenderText(this->renderer())) {
        if (change != NoChange || needsStyleRecalc())
            renderer->setStyle(document().ensureStyleResolver().styleForText(this));
        if (needsStyleRecalc())
            renderer->setText(dataImpl());
        clearNeedsStyleRecalc();
    } else if (needsStyleRecalc() || needsWhitespaceRenderer()) {
        reattach();
        reattachWhitespaceSiblings(nextTextSibling);
    }
}

// If a whitespace node had no renderer and goes through a recalcStyle it may
// need to create one if the parent style now has white-space: pre.
bool Text::needsWhitespaceRenderer()
{
    ASSERT(!renderer());
    if (RenderStyle* style = parentRenderStyle())
        return style->preserveNewline();
    return false;
}

void Text::updateTextRenderer(unsigned offsetOfReplacedData, unsigned lengthOfReplacedData, RecalcStyleBehavior recalcStyleBehavior)
{
    if (!inActiveDocument())
        return;
    RenderText* textRenderer = toRenderText(renderer());
    if (!textRenderer || !textRendererIsNeeded(*textRenderer->style(), *textRenderer->parent())) {
        lazyReattachIfAttached();
        // FIXME: Editing should be updated so this is not neccesary.
        if (recalcStyleBehavior == DeprecatedRecalcStyleImmediatlelyForEditing)
            document().updateRenderTreeIfNeeded();
        return;
    }
    textRenderer->setTextWithOffset(dataImpl(), offsetOfReplacedData, lengthOfReplacedData);
}

PassRefPtr<Text> Text::cloneWithData(const String& data)
{
    return create(document(), data);
}

#ifndef NDEBUG
void Text::formatForDebugger(char *buffer, unsigned length) const
{
    StringBuilder result;
    String s;

    result.append(nodeName());

    s = data();
    if (s.length() > 0) {
        if (result.length())
            result.appendLiteral("; ");
        result.appendLiteral("value=");
        result.append(s);
    }

    strncpy(buffer, result.toString().utf8().data(), length - 1);
}
#endif

} // namespace WebCore