/****************************************************************************

**

** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the QtGui module of the Qt Toolkit.

**

** $QT_BEGIN_LICENSE:LGPL$

** No Commercial Usage

** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** GNU Lesser General Public License Usage

** Alternatively, this file may be used under the terms of the GNU Lesser

** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at qt-info@nokia.com.

**

**

**

**

**

**

**

**

** $QT_END_LICENSE$

**

****************************************************************************/

#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>

QT_BEGIN_NAMESPACE

#define PMDEBUG if(0) qDebug

// The VxWorks DIAB compiler crashes when initializing the anonymouse union with { a7 }

#if !defined(Q_CC_DIAB)

#  define QT_INIT_TEXTUNDOCOMMAND(c, a1, a2, a3, a4, a5, a6, a7, a8) \

          QTextUndoCommand c = { a1, a2, 0, 0, quint8(a3), a4, a5, a6, { a7 }, a8 }

#else

#  define QT_INIT_TEXTUNDOCOMMAND(c, a1, a2, a3, a4, a5, a6, a7, a8) \

          QTextUndoCommand c = { a1, a2, 0, 0, a3, a4, a5, a6 }; c.blockFormat = a7; c.revision = a8

#endif

/*

  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 its

  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),

    docChangeOldLength(0),

    docChangeLength(0),

    framesDirty(true),

    rtFrame(0),

    initialBlockCharFormatIndex(-1) // set correctly later in init()

{

    editBlock = 0;

    editBlockCursorPosition = -1;

    docChangeFrom = -1;

    undoState = 0;

    revision = -1; // init() inserts a block, bringing it to 0

    lout = 0;

    modified = false;

    modifiedState = 0;

    undoEnabled = true;

    inContentsChange = false;

    blockCursorAdjustment = false;

    defaultTextOption.setTabStop(80); // same as in qtextengine.cpp

    defaultTextOption.setWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);

    indentWidth = 40;

    documentMargin = 4;

    maximumBlockCount = 0;

    needsEnsureMaximumBlockCount = false;

    unreachableCharacterCount = 0;

    lastBlockCount = 0;

}

void QTextDocumentPrivate::init()

{

    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;

}

void QTextDocumentPrivate::clear()

{

    Q_Q(QTextDocument);

    foreach (QTextCursorPrivate *curs, cursors) {

        curs->setPosition(0);

        curs->currentCharFormat = -1;

        curs->anchor = 0;

        curs->adjusted_anchor = 0;

    }

    QList<QTextCursorPrivate *>oldCursors = cursors;

    QT_TRY{

        cursors.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();

        clearUndoRedoStacks(QTextDocument::UndoAndRedoStacks);

        text = QString();

        unreachableCharacterCount = 0;

        modifiedState = 0;

        modified = false;

        formats = QTextFormatCollection();

        int len = fragments.length();

        fragments.clear();

        blocks.clear();

        cachedResources.clear();

        delete rtFrame;

        rtFrame = 0;

        init();

        cursors = oldCursors;

        inContentsChange = true;

        q->contentsChange(0, len, 0);

        inContentsChange = false;

        if (lout)

            lout->documentChanged(0, len, 0);

    } QT_CATCH(...) {

        cursors = oldCursors; // at least recover the cursors

        QT_RETHROW;

    }

}

QTextDocumentPrivate::~QTextDocumentPrivate()

{

    foreach (QTextCursorPrivate *curs, cursors)

        curs->priv = 0;

    cursors.clear();

    undoState = 0;

    undoEnabled = true;

    clearUndoRedoStacks(QTextDocument::RedoStack);

}

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();

    emit q->documentLayoutChanged();

    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);

    int ob = blocks.findNode(pos);

    bool atBlockEnd = true;

    bool atBlockStart = true;

    int oldRevision = 0;

    if (ob) {

        atBlockEnd = (pos - blocks.position(ob) == blocks.size(ob)-1);

        atBlockStart = ((int)blocks.position(ob) == pos);

        oldRevision = blocks.fragment(ob)->revision;

    }

    const int fragment = insert_block(pos, strPos, charFormat, blockFormat, op, QTextUndoCommand::BlockRemoved);

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

    int b = blocks.findNode(pos);

    QTextBlockData *B = blocks.fragment(b);

    QT_INIT_TEXTUNDOCOMMAND(c, QTextUndoCommand::BlockInserted, (editBlock != 0),

                            op, charFormat, strPos, pos, blockFormat,

                            B->revision);

    appendUndoItem(c);

    Q_ASSERT(undoState == undoStack.size());

    // update revision numbers of the modified blocks.

    B->revision = (atBlockEnd && !atBlockStart)? oldRevision : revision;

    b = blocks.next(b);

    if (b) {

        B = blocks.fragment(b);

        B->revision = atBlockStart ? oldRevision : revision;

    }

    if (formats.charFormat(charFormat).objectIndex() == -1)

        needsEnsureMaximumBlockCount = true;

    endEditBlock();

    return fragment;

}

int QTextDocumentPrivate::insertBlock(int pos, int blockFormat, int charFormat, QTextUndoCommand::Operation op)

{

    return insertBlock(QChar::ParagraphSeparator, pos, blockFormat, charFormat, op);

}

void QTextDocumentPrivate::insert(int pos, int strPos, int strLength, int format)

{

    if (strLength <= 0)

        return;

    Q_ASSERT(pos >= 0 && pos < fragments.length());

    Q_ASSERT(formats.format(format).isCharFormat());

    insert_string(pos, strPos, strLength, format, QTextUndoCommand::MoveCursor);

    if (undoEnabled) {

        int b = blocks.findNode(pos);

        QTextBlockData *B = blocks.fragment(b);

        QT_INIT_TEXTUNDOCOMMAND(c, QTextUndoCommand::Inserted, (editBlock != 0),

                                QTextUndoCommand::MoveCursor, format, strPos, pos, strLength,

                                B->revision);

        appendUndoItem(c);

        B->revision = revision;

        Q_ASSERT(undoState == undoStack.size());

    }

    finishEdit();

}

void QTextDocumentPrivate::insert(int pos, const QString &str, int format)

{

    if (str.size() == 0)

        return;

    Q_ASSERT(noBlockInString(str));

    int strPos = text.length();

    text.append(str);

    insert(pos, strPos, str.length(), format);

}

int QTextDocumentPrivate::remove_string(int pos, uint length, QTextUndoCommand::Operation op)

{

    Q_ASSERT(pos >= 0);

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

    Q_ASSERT(blocks.length() >= pos+(int)length);

    int b = blocks.findNode(pos);

    uint x = fragments.findNode(pos);

    Q_ASSERT(blocks.size(b) > length);

    Q_ASSERT(x && fragments.position(x) == (uint)pos && fragments.size(x) == length);

    Q_ASSERT(noBlockInString(text.mid(fragments.fragment(x)->stringPosition, length)));

    blocks.setSize(b, blocks.size(b)-length);

    QTextFrame *frame = qobject_cast<QTextFrame *>(objectForFormat(fragments.fragment(x)->format));

    if (frame) {

        frame->d_func()->fragmentRemoved(text.at(fragments.fragment(x)->stringPosition), x);

        framesDirty = true;

    }

    const int w = fragments.erase_single(x);

    if (!undoEnabled)

        unreachableCharacterCount += length;

    adjustDocumentChangesAndCursors(pos, -int(length), op);

    return w;

}

int QTextDocumentPrivate::remove_block(int pos, int *blockFormat, int command, QTextUndoCommand::Operation op)

{

    Q_ASSERT(pos >= 0);

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

    Q_ASSERT(blocks.length() > pos);

    int b = blocks.findNode(pos);

    uint x = fragments.findNode(pos);