qtextdocument_p.cpp

奇趣公司比较新的qt/emd版本

QString QTextDocumentPrivate::plainText() const
{
    QString result;
    result.reserve(length());
    for (QTextDocumentPrivate::FragmentIterator it = begin(); it != end(); ++it) {
        const QTextFragmentData *f = *it;
        result += QString::fromRawData(text.unicode() + f->stringPosition, f->size);
    }
    // remove trailing block separator
    result.chop(1);
    return result;
}

int QTextDocumentPrivate::blockCharFormatIndex(int node) const
{
    int pos = blocks.position(node);
    if (pos == 0)
        return initialBlockCharFormatIndex;

    return fragments.find(pos - 1)->format;
}

int QTextDocumentPrivate::nextCursorPosition(int position, QTextLayout::CursorMode mode) const
{
    if (position == length()-1)
        return position;

    QTextBlock it = blocksFind(position);
    int start = it.position();
    int end = start + it.length() - 1;
    if (position == end)
        return end + 1;

    return it.layout()->nextCursorPosition(position-start, mode) + start;
}

int QTextDocumentPrivate::previousCursorPosition(int position, QTextLayout::CursorMode mode) const
{
    if (position == 0)
        return position;

    QTextBlock it = blocksFind(position);
    int start = it.position();
    if (position == start)
        return start - 1;

    return it.layout()->previousCursorPosition(position-start, mode) + start;
}

void QTextDocumentPrivate::changeObjectFormat(QTextObject *obj, int format)
{
    beginEditBlock();
    int objectIndex = obj->objectIndex();
    int oldFormatIndex = formats.objectFormatIndex(objectIndex);
    formats.setObjectFormatIndex(objectIndex, format);

    QTextBlockGroup *b = qobject_cast<QTextBlockGroup *>(obj);
    if (b) {
        b->d_func()->markBlocksDirty();
    }
    QTextFrame *f = qobject_cast<QTextFrame *>(obj);
    if (f)
        documentChange(f->firstPosition(), f->lastPosition() - f->firstPosition());

    QTextUndoCommand c = { QTextUndoCommand::GroupFormatChange, true, QTextUndoCommand::MoveCursor, oldFormatIndex,
                      0, 0, { obj->d_func()->objectIndex } };
    appendUndoItem(c);

    endEditBlock();
}

static QTextFrame *findChildFrame(QTextFrame *f, int pos)
{
    // ##### use binary search
    QList<QTextFrame *> children = f->childFrames();
    for (int i = 0; i < children.size(); ++i) {
        QTextFrame *c = children.at(i);
        if (pos >= c->firstPosition() && pos <= c->lastPosition())
            return c;
    }
    return 0;
}

QTextFrame *QTextDocumentPrivate::rootFrame() const
{
    if (!rtFrame) {
        QTextFrameFormat defaultRootFrameFormat;
        defaultRootFrameFormat.setMargin(DefaultRootFrameMargin);
        rtFrame = qobject_cast<QTextFrame *>(const_cast<QTextDocumentPrivate *>(this)->createObject(defaultRootFrameFormat));
    }
    return rtFrame;
}

QTextFrame *QTextDocumentPrivate::frameAt(int pos) const
{
    QTextFrame *f = rootFrame();

    while (1) {
        QTextFrame *c = findChildFrame(f, pos);
        if (!c)
            return f;
        f = c;
    }
}

void QTextDocumentPrivate::clearFrame(QTextFrame *f)
{
    for (int i = 0; i < f->d_func()->childFrames.count(); ++i)
        clearFrame(f->d_func()->childFrames.at(i));
    f->d_func()->childFrames.clear();
    f->d_func()->parentFrame = 0;
}

void QTextDocumentPrivate::scan_frames(int pos, int charsRemoved, int charsAdded)
{
    // ###### optimise
    Q_UNUSED(pos);
    Q_UNUSED(charsRemoved);
    Q_UNUSED(charsAdded);

    QTextFrame *f = rootFrame();
    clearFrame(f);

    for (FragmentIterator it = begin(); it != end(); ++it) {
        // QTextFormat fmt = formats.format(it->format);
        QTextFrame *frame = qobject_cast<QTextFrame *>(objectForFormat(it->format));
        if (!frame)
            continue;

        Q_ASSERT(it.size() == 1);
        QChar ch = text.at(it->stringPosition);

        if (ch == QTextBeginningOfFrame) {
            if (f != frame) {
                // f == frame happens for tables
                Q_ASSERT(frame->d_func()->fragment_start == it.n || frame->d_func()->fragment_start == 0);
                frame->d_func()->parentFrame = f;
                f->d_func()->childFrames.append(frame);
                f = frame;
            }
        } else if (ch == QTextEndOfFrame) {
            Q_ASSERT(f == frame);
            Q_ASSERT(frame->d_func()->fragment_end == it.n || frame->d_func()->fragment_end == 0);
            f = frame->d_func()->parentFrame;
        } else if (ch == QChar::ObjectReplacementCharacter) {
            Q_ASSERT(f != frame);
            Q_ASSERT(frame->d_func()->fragment_start == it.n || frame->d_func()->fragment_start == 0);
            Q_ASSERT(frame->d_func()->fragment_end == it.n || frame->d_func()->fragment_end == 0);
            frame->d_func()->parentFrame = f;
            f->d_func()->childFrames.append(frame);
        } else {
            Q_ASSERT(false);
        }
    }
    Q_ASSERT(f == rtFrame);
    framesDirty = false;
}

void QTextDocumentPrivate::insert_frame(QTextFrame *f)
{
    int start = f->firstPosition();
    int end = f->lastPosition();
    QTextFrame *parent = frameAt(start-1);
    Q_ASSERT(parent == frameAt(end+1));

    if (start != end) {
        // iterator over the parent and move all children contained in my frame to myself
        for (int i = 0; i < parent->d_func()->childFrames.size(); ++i) {
            QTextFrame *c = parent->d_func()->childFrames.at(i);
            if (start < c->firstPosition() && end > c->lastPosition()) {
                parent->d_func()->childFrames.removeAt(i);
                f->d_func()->childFrames.append(c);
                c->d_func()->parentFrame = f;
            }
        }
    }
    // insert at the correct position
    int i = 0;
    for (; i < parent->d_func()->childFrames.size(); ++i) {
        QTextFrame *c = parent->d_func()->childFrames.at(i);
        if (c->firstPosition() > end)
            break;
    }
    parent->d_func()->childFrames.insert(i, f);
    f->d_func()->parentFrame = parent;
}

QTextFrame *QTextDocumentPrivate::insertFrame(int start, int end, const QTextFrameFormat &format)
{
    Q_ASSERT(start >= 0 && start < length());
    Q_ASSERT(end >= 0 && end < length());
    Q_ASSERT(start <= end || end == -1);

    if (start != end && frameAt(start) != frameAt(end))
        return 0;

    beginEditBlock();

    QTextFrame *frame = qobject_cast<QTextFrame *>(createObject(format));
    Q_ASSERT(frame);

    // #### using the default block and char format below might be wrong
    int idx = formats.indexForFormat(QTextBlockFormat());
    QTextCharFormat cfmt;
    cfmt.setObjectIndex(frame->objectIndex());
    int charIdx = formats.indexForFormat(cfmt);

    insertBlock(QTextBeginningOfFrame, start, idx, charIdx, QTextUndoCommand::MoveCursor);
    insertBlock(QTextEndOfFrame, ++end, idx, charIdx, QTextUndoCommand::KeepCursor);

    frame->d_func()->fragment_start = find(start).n;
    frame->d_func()->fragment_end = find(end).n;

    insert_frame(frame);

    endEditBlock();

    return frame;
}

void QTextDocumentPrivate::removeFrame(QTextFrame *frame)
{
    QTextFrame *parent = frame->d_func()->parentFrame;
    if (!parent)
        return;

    int start = frame->firstPosition();
    int end = frame->lastPosition();
    Q_ASSERT(end >= start);

    beginEditBlock();

    // remove already removes the frames from the tree
    remove(end, 1);
    remove(start-1, 1);

    endEditBlock();
}

QTextObject *QTextDocumentPrivate::objectForIndex(int objectIndex) const
{
    if (objectIndex < 0)
        return 0;

    QTextObject *object = objects.value(objectIndex, 0);
    if (!object) {
        QTextDocumentPrivate *that = const_cast<QTextDocumentPrivate *>(this);
        QTextFormat fmt = formats.objectFormat(objectIndex);
        object = that->createObject(fmt, objectIndex);
    }
    return object;
}

QTextObject *QTextDocumentPrivate::objectForFormat(int formatIndex) const
{
    int objectIndex = formats.format(formatIndex).objectIndex();
    return objectForIndex(objectIndex);
}

QTextObject *QTextDocumentPrivate::objectForFormat(const QTextFormat &f) const
{
    return objectForIndex(f.objectIndex());
}

QTextObject *QTextDocumentPrivate::createObject(const QTextFormat &f, int objectIndex)
{
    QTextObject *obj = document()->createObject(f);

    if (obj) {
        obj->d_func()->pieceTable = this;
        obj->d_func()->objectIndex = objectIndex == -1 ? formats.createObjectIndex(f) : objectIndex;
        objects[obj->d_func()->objectIndex] = obj;
    }

    return obj;
}

void QTextDocumentPrivate::deleteObject(QTextObject *object)
{
    const int objIdx = object->d_func()->objectIndex;
    objects.remove(objIdx);
    delete object;
}

void QTextDocumentPrivate::contentsChanged()
{
    Q_Q(QTextDocument);
    if (editBlock)
        return;

    bool m = undoEnabled ? (modifiedState != undoState) : true;
    if (modified != m) {
        modified = m;
        emit q->modificationChanged(modified);
    }

    emit q->contentsChanged();
}

void QTextDocumentPrivate::compressPieceTable()
{
    if (undoEnabled)
        return;

    const uint garbageCollectionThreshold = 96 * 1024; // bytes

    //qDebug() << "unreachable bytes:" << unreachableCharacterCount * sizeof(QChar) << " -- limit" << garbageCollectionThreshold << "text size =" << text.size() << "capacity:" << text.capacity();

    bool compressTable = unreachableCharacterCount * sizeof(QChar) > garbageCollectionThreshold
                         && text.size() >= text.capacity() * 0.9;
    if (!compressTable)
        return;

    QString newText;
    newText.resize(text.size());
    QChar *newTextPtr = newText.data();
    int newLen = 0;

    for (FragmentMap::Iterator it = fragments.begin(); !it.atEnd(); ++it) {
        qMemCopy(newTextPtr, text.constData() + it->stringPosition, it->size * sizeof(QChar));
        it->stringPosition = newLen;
        newTextPtr += it->size;
        newLen += it->size;
    }

    newText.resize(newLen);
    newText.squeeze();
    //qDebug() << "removed" << text.size() - newText.size() << "characters";
    text = newText;
    unreachableCharacterCount = 0;
}

void QTextDocumentPrivate::setModified(bool m)
{
    Q_Q(QTextDocument);
    if (m == modified)
        return;

    modified = m;
    if (!modified)
        modifiedState = undoState;
    else
        modifiedState = -1;

    emit q->modificationChanged(modified);
}

void QTextDocumentPrivate::ensureMaximumBlockCount()
{
    if (maximumBlockCount <= 0)
        return;
    if (blocks.numNodes() <= maximumBlockCount)
        return;

    beginEditBlock();

    const int blocksToRemove = blocks.numNodes() - maximumBlockCount;
    QTextCursor cursor(this, 0);
    cursor.movePosition(QTextCursor::NextBlock, QTextCursor::KeepAnchor, blocksToRemove);

    unreachableCharacterCount += cursor.selectionEnd() - cursor.selectionStart();

    // preserve the char format of the paragraph that is to become the new first one
    QTextCharFormat charFmt = cursor.blockCharFormat();
    cursor.removeSelectedText();
    cursor.setBlockCharFormat(charFmt);

    endEditBlock();

    compressPieceTable();
}