position.cpp

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        }
    }
    
    if (node()->hasTagName(brTag) && pos.isCandidate())
        return true;
                
    if (pos.node()->hasTagName(brTag) && isCandidate())
        return true;
                
    if (node()->enclosingBlockFlowElement() != pos.node()->enclosingBlockFlowElement())
        return true;

    if (node()->isTextNode() && !inRenderedText())
        return false;

    if (pos.node()->isTextNode() && !pos.inRenderedText())
        return false;

    int thisRenderedOffset = renderedOffset();
    int posRenderedOffset = pos.renderedOffset();

    if (renderer == posRenderer && thisRenderedOffset == posRenderedOffset)
        return false;

    int ignoredCaretOffset;
    InlineBox* b1;
    getInlineBoxAndOffset(DOWNSTREAM, b1, ignoredCaretOffset);
    InlineBox* b2;
    pos.getInlineBoxAndOffset(DOWNSTREAM, b2, ignoredCaretOffset);

    LOG(Editing, "renderer:               %p [%p]\n", renderer, b1);
    LOG(Editing, "thisRenderedOffset:         %d\n", thisRenderedOffset);
    LOG(Editing, "posRenderer:            %p [%p]\n", posRenderer, b2);
    LOG(Editing, "posRenderedOffset:      %d\n", posRenderedOffset);
    LOG(Editing, "node min/max:           %d:%d\n", caretMinOffset(node()), caretMaxRenderedOffset(node()));
    LOG(Editing, "pos node min/max:       %d:%d\n", caretMinOffset(pos.node()), caretMaxRenderedOffset(pos.node()));
    LOG(Editing, "----------------------------------------------------------------------\n");

    if (!b1 || !b2) {
        return false;
    }

    if (b1->root() != b2->root()) {
        return true;
    }

    if (nextRenderedEditable(node()) == pos.node() && 
        thisRenderedOffset == (int)caretMaxRenderedOffset(node()) && posRenderedOffset == 0) {
        return false;
    }
    
    if (previousRenderedEditable(node()) == pos.node() && 
        thisRenderedOffset == 0 && posRenderedOffset == (int)caretMaxRenderedOffset(pos.node())) {
        return false;
    }

    return true;
}

// This assumes that it starts in editable content.
Position Position::leadingWhitespacePosition(EAffinity affinity, bool considerNonCollapsibleWhitespace) const
{
    ASSERT(isEditablePosition(*this));
    if (isNull())
        return Position();
    
    if (upstream().node()->hasTagName(brTag))
        return Position();

    Position prev = previousCharacterPosition(affinity);
    if (prev != *this && prev.node()->inSameContainingBlockFlowElement(node()) && prev.node()->isTextNode()) {
        String string = static_cast<Text *>(prev.node())->data();
        UChar c = string[prev.offset()];
        if (considerNonCollapsibleWhitespace ? (isSpaceOrNewline(c) || c == noBreakSpace) : isCollapsibleWhitespace(c))
            if (isEditablePosition(prev))
                return prev;
    }

    return Position();
}

// This assumes that it starts in editable content.
Position Position::trailingWhitespacePosition(EAffinity, bool considerNonCollapsibleWhitespace) const
{
    ASSERT(isEditablePosition(*this));
    if (isNull())
        return Position();
    
    VisiblePosition v(*this);
    UChar c = v.characterAfter();
    // The space must not be in another paragraph and it must be editable.
    if (!isEndOfParagraph(v) && v.next(true).isNotNull())
        if (considerNonCollapsibleWhitespace ? (isSpaceOrNewline(c) || c == noBreakSpace) : isCollapsibleWhitespace(c))
            return *this;
    
    return Position();
}

void Position::getInlineBoxAndOffset(EAffinity affinity, InlineBox*& inlineBox, int& caretOffset) const
{
    TextDirection primaryDirection = LTR;
    for (RenderObject* r = node()->renderer(); r; r = r->parent()) {
        if (r->isBlockFlow()) {
            primaryDirection = r->style()->direction();
            break;
        }
    }
    getInlineBoxAndOffset(affinity, primaryDirection, inlineBox, caretOffset);
}

static bool isNonTextLeafChild(RenderObject* object)
{
    if (object->firstChild())
        return false;
    if (object->isText())
        return false;
    return true;
}

static InlineTextBox* searchAheadForBetterMatch(RenderObject* renderer)
{
    InlineTextBox* match = 0;
    int minOffset = INT_MAX;
    RenderBlock* container = renderer->containingBlock();
    RenderObject* next = renderer;
    while ((next = next->nextInPreOrder(container))) {
        if (next->isRenderBlock())
            break;
        if (next->isBR())
            break;
        if (isNonTextLeafChild(next))
            break;
        if (next->isText()) {
            for (InlineTextBox* box = toRenderText(next)->firstTextBox(); box; box = box->nextTextBox()) {
                int caretMinOffset = box->caretMinOffset();
                if (caretMinOffset < minOffset) {
                    match = box;
                    minOffset = caretMinOffset;
                }
            }
        }
    }
    return match;
}

void Position::getInlineBoxAndOffset(EAffinity affinity, TextDirection primaryDirection, InlineBox*& inlineBox, int& caretOffset) const
{
    caretOffset = offset();
    RenderObject* renderer = node()->renderer();
    if (!renderer->isText()) {
        inlineBox = renderer->isBox() ? toRenderBox(renderer)->inlineBoxWrapper() : 0;
        if (!inlineBox || caretOffset > inlineBox->caretMinOffset() && caretOffset < inlineBox->caretMaxOffset())
            return;
    } else {
        RenderText* textRenderer = toRenderText(renderer);

        InlineTextBox* box;
        InlineTextBox* candidate = 0;

        for (box = textRenderer->firstTextBox(); box; box = box->nextTextBox()) {
            int caretMinOffset = box->caretMinOffset();
            int caretMaxOffset = box->caretMaxOffset();

            if (caretOffset < caretMinOffset || caretOffset > caretMaxOffset || caretOffset == caretMaxOffset && box->isLineBreak())
                continue;

            if (caretOffset > caretMinOffset && caretOffset < caretMaxOffset) {
                inlineBox = box;
                return;
            }

            if ((caretOffset == caretMinOffset) ^ (affinity == UPSTREAM))
                break;

            candidate = box;
        }
        if (candidate && !box && affinity == DOWNSTREAM) {
            box = searchAheadForBetterMatch(textRenderer);
            if (box)
                caretOffset = box->caretMinOffset();
        }
        inlineBox = box ? box : candidate;
    }

    if (!inlineBox)
        return;

    unsigned char level = inlineBox->bidiLevel();

    if (inlineBox->direction() == primaryDirection) {
        if (caretOffset == inlineBox->caretRightmostOffset()) {
            InlineBox* nextBox = inlineBox->nextLeafChild();
            if (!nextBox || nextBox->bidiLevel() >= level)
                return;

            level = nextBox->bidiLevel();
            InlineBox* prevBox = inlineBox;
            do {
                prevBox = prevBox->prevLeafChild();
            } while (prevBox && prevBox->bidiLevel() > level);

            if (prevBox && prevBox->bidiLevel() == level)   // For example, abc FED 123 ^ CBA
                return;

            // For example, abc 123 ^ CBA
            while (InlineBox* nextBox = inlineBox->nextLeafChild()) {
                if (nextBox->bidiLevel() < level)
                    break;
                inlineBox = nextBox;
            }
            caretOffset = inlineBox->caretRightmostOffset();
        } else {
            InlineBox* prevBox = inlineBox->prevLeafChild();
            if (!prevBox || prevBox->bidiLevel() >= level)
                return;

            level = prevBox->bidiLevel();
            InlineBox* nextBox = inlineBox;
            do {
                nextBox = nextBox->nextLeafChild();
            } while (nextBox && nextBox->bidiLevel() > level);

            if (nextBox && nextBox->bidiLevel() == level)
                return;

            while (InlineBox* prevBox = inlineBox->prevLeafChild()) {
                if (prevBox->bidiLevel() < level)
                    break;
                inlineBox = prevBox;
            }
            caretOffset = inlineBox->caretLeftmostOffset();
        }
        return;
    }

    if (caretOffset == inlineBox->caretLeftmostOffset()) {
        InlineBox* prevBox = inlineBox->prevLeafChild();
        if (!prevBox || prevBox->bidiLevel() < level) {
            // Left edge of a secondary run. Set to the right edge of the entire run.
            while (InlineBox* nextBox = inlineBox->nextLeafChild()) {
                if (nextBox->bidiLevel() < level)
                    break;
                inlineBox = nextBox;
            }
            caretOffset = inlineBox->caretRightmostOffset();
        } else if (prevBox->bidiLevel() > level) {
            // Right edge of a "tertiary" run. Set to the left edge of that run.
            while (InlineBox* tertiaryBox = inlineBox->prevLeafChild()) {
                if (tertiaryBox->bidiLevel() <= level)
                    break;
                inlineBox = tertiaryBox;
            }
            caretOffset = inlineBox->caretLeftmostOffset();
        }
    } else {
        InlineBox* nextBox = inlineBox->nextLeafChild();
        if (!nextBox || nextBox->bidiLevel() < level) {
            // Right edge of a secondary run. Set to the left edge of the entire run.
            while (InlineBox* prevBox = inlineBox->prevLeafChild()) {
                if (prevBox->bidiLevel() < level)
                    break;
                inlineBox = prevBox;
            }
            caretOffset = inlineBox->caretLeftmostOffset();
        } else if (nextBox->bidiLevel() > level) {
            // Left edge of a "tertiary" run. Set to the right edge of that run.
            while (InlineBox* tertiaryBox = inlineBox->nextLeafChild()) {
                if (tertiaryBox->bidiLevel() <= level)
                    break;
                inlineBox = tertiaryBox;
            }
            caretOffset = inlineBox->caretRightmostOffset();
        }
    }
}

void Position::debugPosition(const char* msg) const
{
    if (isNull())
        fprintf(stderr, "Position [%s]: null\n", msg);
    else
        fprintf(stderr, "Position [%s]: %s [%p] at %d\n", msg, node()->nodeName().utf8().data(), node(), offset());
}

#ifndef NDEBUG

void Position::formatForDebugger(char* buffer, unsigned length) const
{
    String result;
    
    if (isNull())
        result = "<null>";
    else {
        char s[1024];
        result += "offset ";
        result += String::number(offset());
        result += " of ";
        node()->formatForDebugger(s, sizeof(s));
        result += s;
    }
          
    strncpy(buffer, result.utf8().data(), length - 1);
}

void Position::showTreeForThis() const
{
    if (node())
        node()->showTreeForThis();
}

#endif

Position startPosition(const Range* r)
{
    return r ? r->startPosition() : Position();
}

Position endPosition(const Range* r)
{
    return r ? r->endPosition() : Position();
}

} // namespace WebCore

#ifndef NDEBUG

void showTree(const WebCore::Position& pos)
{
    pos.showTreeForThis();
}

void showTree(const WebCore::Position* pos)
{
    if (pos)
        pos->showTreeForThis();
}

#endif