qtextdocument_p.cpp

奇趣公司比较新的qt/emd版本

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#include <private/qtools_p.h>
#include <qdebug.h>

#include "qtextdocument_p.h"
#include "qtextdocument.h"
#include <qtextformat.h>
#include "qtextformat_p.h"
#include "qtextobject_p.h"
#include "qtextcursor.h"
#include "qtextimagehandler_p.h"
#include "qtextcursor_p.h"
#include "qtextdocumentlayout_p.h"
#include "qtexttable.h"
#include "qtextengine_p.h"

#include <stdlib.h>

#define PMDEBUG if(0) qDebug

/*
  Structure of a document:

  DOCUMENT :== FRAME_CONTENTS
  FRAME :== START_OF_FRAME  FRAME_CONTENTS END_OF_FRAME
  FRAME_CONTENTS = LIST_OF_BLOCKS ((FRAME | TABLE) LIST_OF_BLOCKS)*
  TABLE :== (START_OF_FRAME TABLE_CELL)+ END_OF_FRAME
  TABLE_CELL = FRAME_CONTENTS
  LIST_OF_BLOCKS :== (BLOCK END_OF_PARA)* BLOCK
  BLOCK :== (FRAGMENT)*
  FRAGMENT :== String of characters

  END_OF_PARA :== 0x2029 # Paragraph separator in Unicode
  START_OF_FRAME :== 0xfdd0
  END_OF_FRAME := 0xfdd1

  Note also that LIST_OF_BLOCKS can be empty. Nevertheless, there is
  at least one valid cursor position there where you could start
  typing. The block format is in this case determined by the last
  END_OF_PARA/START_OF_FRAME/END_OF_FRAME (see below).

  Lists are not in here, as they are treated specially. A list is just
  a collection of (not neccessarily connected) blocks, that share the
  same objectIndex() in the format that refers to the list format and
  object.

  The above does not clearly note where formats are. Here's
  how it looks currently:

  FRAGMENT: one charFormat associated

  END_OF_PARA: one charFormat, and a blockFormat for the _next_ block.

  START_OF_FRAME: one char format, and a blockFormat (for the next
  block). The format associated with the objectIndex() of the
  charFormat decides whether this is a frame or table and it's
  properties

  END_OF_FRAME: one charFormat and a blockFormat (for the next
  block). The object() of the charFormat is the same as for the
  corresponding START_OF_BLOCK.


  The document is independent of the layout with certain restrictions:

  * Cursor movement (esp. up and down) depend on the layout.
  * You cannot have more than one layout, as the layout data of QTextObjects
    is stored in the text object itself.

*/

void QTextBlockData::invalidate() const
{
    if (layout)
        layout->engine()->invalidate();
}

static bool isValidBlockSeparator(const QChar &ch)
{
    return ch == QChar::ParagraphSeparator
        || ch == QTextBeginningOfFrame
        || ch == QTextEndOfFrame;
}

#ifndef QT_NO_DEBUG
static bool noBlockInString(const QString &str)
{
    return !str.contains(QChar::ParagraphSeparator)
        && !str.contains(QTextBeginningOfFrame)
        && !str.contains(QTextEndOfFrame);
}
#endif

bool QTextUndoCommand::tryMerge(const QTextUndoCommand &other)
{
    if (command != other.command)
        return false;

    if (command == Inserted
        && (pos + length == other.pos)
        && (strPos + length == other.strPos)
        && format == other.format) {

        length += other.length;
        return true;
    }

    // removal to the 'right' using 'Delete' key
    if (command == Removed
        && pos == other.pos
        && (strPos + length == other.strPos)
        && format == other.format) {

        length += other.length;
        return true;
    }

    // removal to the 'left' using 'Backspace'
    if (command == Removed
        && (other.pos + other.length == pos)
        && (other.strPos + other.length == strPos)
        && (format == other.format)) {

        int l = length;
        (*this) = other;

        length += l;
        return true;
    }

    return false;
}

QTextDocumentPrivate::QTextDocumentPrivate()
    : wasUndoAvailable(false)
    , wasRedoAvailable(false)
{
    editBlock = 0;
    docChangeFrom = -1;

    undoState = 0;

    lout = 0;

    modified = false;
    modifiedState = 0;

    undoEnabled = true;
    inContentsChange = false;
    defaultTextOption.setTabStop(80); // same as in qtextengine.cpp
    defaultTextOption.setWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);

    maximumBlockCount = 0;
    unreachableCharacterCount = 0;
    lastBlockCount = 0;
}

void QTextDocumentPrivate::init()
{
    rtFrame = 0;
    framesDirty = false;

    bool undoState = undoEnabled;
    undoEnabled = false;
    initialBlockCharFormatIndex = formats.indexForFormat(QTextCharFormat());
    insertBlock(0, formats.indexForFormat(QTextBlockFormat()), formats.indexForFormat(QTextCharFormat()));
    undoEnabled = undoState;
    modified = false;
    modifiedState = 0;
    lastBlockCount = blocks.numNodes();
}

void QTextDocumentPrivate::clear()
{
    Q_Q(QTextDocument);
    for (int i = 0; i < cursors.count(); ++i) {
        cursors.at(i)->setPosition(0);
        cursors.at(i)->anchor = 0;
    }

    QList<QTextCursorPrivate *>oldCursors = cursors;
    cursors.clear();
    changedCursors.clear();

    QMap<int, QTextObject *>::Iterator objectIt = objects.begin();
    while (objectIt != objects.end()) {
        if (*objectIt != rtFrame) {
            delete *objectIt;
            objectIt = objects.erase(objectIt);
        } else {
            ++objectIt;
        }
    }
    // also clear out the remaining root frame pointer
    // (we're going to delete the object further down)
    objects.clear();

    title.clear();
    undoState = 0;
    truncateUndoStack();
    text = QString();
    unreachableCharacterCount = 0;
    modifiedState = 0;
    modified = false;
    formats = QTextFormatCollection();
    int len = fragments.length();
    fragments.clear();
    blocks.clear();
    cachedResources.clear();
    delete rtFrame;
    init();
    cursors = oldCursors;
    inContentsChange = true;
    q->contentsChange(0, len, 0);
    inContentsChange = false;
    if (lout)
        lout->documentChanged(0, len, 0);
}

QTextDocumentPrivate::~QTextDocumentPrivate()
{
    for (int i = 0; i < cursors.count(); ++i)
        cursors.at(i)->priv = 0;
    cursors.clear();
    undoState = 0;
    undoEnabled = true;
    truncateUndoStack();
}

void QTextDocumentPrivate::setLayout(QAbstractTextDocumentLayout *layout)
{
    Q_Q(QTextDocument);
    if (lout == layout)
        return;
    const bool firstLayout = !lout;
    delete lout;
    lout = layout;

    if (!firstLayout)
        for (BlockMap::Iterator it = blocks.begin(); !it.atEnd(); ++it)
            it->free();

    inContentsChange = true;
    emit q->contentsChange(0, 0, length());
    inContentsChange = false;
    if (lout)
        lout->documentChanged(0, 0, length());
}


void QTextDocumentPrivate::insert_string(int pos, uint strPos, uint length, int format, QTextUndoCommand::Operation op)
{
    // ##### optimise when only appending to the fragment!
    Q_ASSERT(noBlockInString(text.mid(strPos, length)));

    split(pos);
    uint x = fragments.insert_single(pos, length);
    QTextFragmentData *X = fragments.fragment(x);
    X->format = format;
    X->stringPosition = strPos;
    uint w = fragments.previous(x);
    if (w)
        unite(w);

    int b = blocks.findNode(pos);
    blocks.setSize(b, blocks.size(b)+length);

    Q_ASSERT(blocks.length() == fragments.length());

    QTextFrame *frame = qobject_cast<QTextFrame *>(objectForFormat(format));
    if (frame) {
        frame->d_func()->fragmentAdded(text.at(strPos), x);
        framesDirty = true;
    }

    adjustDocumentChangesAndCursors(pos, length, op);
}

int QTextDocumentPrivate::insert_block(int pos, uint strPos, int format, int blockFormat, QTextUndoCommand::Operation op, int command)
{
    split(pos);
    uint x = fragments.insert_single(pos, 1);
    QTextFragmentData *X = fragments.fragment(x);
    X->format = format;
    X->stringPosition = strPos;
    // no need trying to unite, since paragraph separators are always in a fragment of their own

    Q_ASSERT(isValidBlockSeparator(text.at(strPos)));
    Q_ASSERT(blocks.length()+1 == fragments.length());

    int block_pos = pos;
    if (blocks.length() && command == QTextUndoCommand::BlockRemoved)
        ++block_pos;
    int size = 1;
    int n = blocks.findNode(block_pos);
    int key = n ? blocks.position(n) : blocks.length();

    Q_ASSERT(n || (!n && block_pos == blocks.length()));
    if (key != block_pos) {
        Q_ASSERT(key < block_pos);
        int oldSize = blocks.size(n);
        blocks.setSize(n, block_pos-key);
        size += oldSize - (block_pos-key);
    }
    int b = blocks.insert_single(block_pos, size);
    QTextBlockData *B = blocks.fragment(b);
    B->format = blockFormat;

    Q_ASSERT(blocks.length() == fragments.length());

    QTextBlockGroup *group = qobject_cast<QTextBlockGroup *>(objectForFormat(blockFormat));
    if (group)
        group->blockInserted(QTextBlock(this, b));

    QTextFrame *frame = qobject_cast<QTextFrame *>(objectForFormat(formats.format(format)));
    if (frame) {
        frame->d_func()->fragmentAdded(text.at(strPos), x);
        framesDirty = true;
    }

    adjustDocumentChangesAndCursors(pos, 1, op);
    return x;
}

int QTextDocumentPrivate::insertBlock(const QChar &blockSeparator,
                                  int pos, int blockFormat, int charFormat, QTextUndoCommand::Operation op)
{
    Q_ASSERT(formats.format(blockFormat).isBlockFormat());
    Q_ASSERT(formats.format(charFormat).isCharFormat());
    Q_ASSERT(pos >= 0 && (pos < fragments.length() || (pos == 0 && fragments.length() == 0)));
    Q_ASSERT(isValidBlockSeparator(blockSeparator));

    beginEditBlock();

    int strPos = text.length();
    text.append(blockSeparator);
    const int fragment = insert_block(pos, strPos, charFormat, blockFormat, op, QTextUndoCommand::BlockRemoved);

    Q_ASSERT(blocks.length() == fragments.length());