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Diffstat (limited to 'src/gui/text/qtextmarkdownwriter.cpp')
| -rw-r--r-- | src/gui/text/qtextmarkdownwriter.cpp | 565 |
1 files changed, 565 insertions, 0 deletions
diff --git a/src/gui/text/qtextmarkdownwriter.cpp b/src/gui/text/qtextmarkdownwriter.cpp new file mode 100644 index 0000000000..c9a63920c3 --- /dev/null +++ b/src/gui/text/qtextmarkdownwriter.cpp @@ -0,0 +1,565 @@ +/**************************************************************************** +** +** Copyright (C) 2019 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the QtGui module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qtextmarkdownwriter_p.h" +#include "qtextdocumentlayout_p.h" +#include "qfontinfo.h" +#include "qfontmetrics.h" +#include "qtextdocument_p.h" +#include "qtextlist.h" +#include "qtexttable.h" +#include "qtextcursor.h" +#include "qtextimagehandler_p.h" +#include "qloggingcategory.h" +#if QT_CONFIG(itemmodel) +#include "qabstractitemmodel.h" +#endif + +QT_BEGIN_NAMESPACE + +Q_LOGGING_CATEGORY(lcMDW, "qt.text.markdown.writer") + +static const QChar Space = QLatin1Char(' '); +static const QChar Newline = QLatin1Char('\n'); +static const QChar LineBreak = QChar(0x2028); +static const QChar DoubleQuote = QLatin1Char('"'); +static const QChar Backtick = QLatin1Char('`'); +static const QChar Period = QLatin1Char('.'); + +QTextMarkdownWriter::QTextMarkdownWriter(QTextStream &stream, QTextDocument::MarkdownFeatures features) + : m_stream(stream), m_features(features) +{ +} + +bool QTextMarkdownWriter::writeAll(const QTextDocument *document) +{ + writeFrame(document->rootFrame()); + return true; +} + +#if QT_CONFIG(itemmodel) +void QTextMarkdownWriter::writeTable(const QAbstractItemModel *table) +{ + QVector<int> tableColumnWidths(table->columnCount()); + for (int col = 0; col < table->columnCount(); ++col) { + tableColumnWidths[col] = table->headerData(col, Qt::Horizontal).toString().length(); + for (int row = 0; row < table->rowCount(); ++row) { + tableColumnWidths[col] = qMax(tableColumnWidths[col], + table->data(table->index(row, col)).toString().length()); + } + } + + // write the header and separator + for (int col = 0; col < table->columnCount(); ++col) { + QString s = table->headerData(col, Qt::Horizontal).toString(); + m_stream << "|" << s << QString(tableColumnWidths[col] - s.length(), Space); + } + m_stream << "|" << Qt::endl; + for (int col = 0; col < tableColumnWidths.length(); ++col) + m_stream << '|' << QString(tableColumnWidths[col], QLatin1Char('-')); + m_stream << '|'<< Qt::endl; + + // write the body + for (int row = 0; row < table->rowCount(); ++row) { + for (int col = 0; col < table->columnCount(); ++col) { + QString s = table->data(table->index(row, col)).toString(); + m_stream << "|" << s << QString(tableColumnWidths[col] - s.length(), Space); + } + m_stream << '|'<< Qt::endl; + } + m_listInfo.clear(); +} +#endif + +void QTextMarkdownWriter::writeFrame(const QTextFrame *frame) +{ + Q_ASSERT(frame); + const QTextTable *table = qobject_cast<const QTextTable*> (frame); + QTextFrame::iterator iterator = frame->begin(); + QTextFrame *child = nullptr; + int tableRow = -1; + bool lastWasList = false; + QVector<int> tableColumnWidths; + if (table) { + tableColumnWidths.resize(table->columns()); + for (int col = 0; col < table->columns(); ++col) { + for (int row = 0; row < table->rows(); ++ row) { + QTextTableCell cell = table->cellAt(row, col); + int cellTextLen = 0; + auto it = cell.begin(); + while (it != cell.end()) { + QTextBlock block = it.currentBlock(); + if (block.isValid()) + cellTextLen += block.text().length(); + ++it; + } + if (cell.columnSpan() == 1 && tableColumnWidths[col] < cellTextLen) + tableColumnWidths[col] = cellTextLen; + } + } + } + while (!iterator.atEnd()) { + if (iterator.currentFrame() && child != iterator.currentFrame()) + writeFrame(iterator.currentFrame()); + else { // no frame, it's a block + QTextBlock block = iterator.currentBlock(); + // Look ahead and detect some cases when we should + // suppress needless blank lines, when there will be a big change in block format + bool nextIsDifferent = false; + bool ending = false; + { + QTextFrame::iterator next = iterator; + ++next; + if (next.atEnd()) { + nextIsDifferent = true; + ending = true; + } else { + QTextBlockFormat format = iterator.currentBlock().blockFormat(); + QTextBlockFormat nextFormat = next.currentBlock().blockFormat(); + if (nextFormat.indent() != format.indent() || + nextFormat.property(QTextFormat::BlockCodeLanguage) != format.property(QTextFormat::BlockCodeLanguage)) + nextIsDifferent = true; + } + } + if (table) { + QTextTableCell cell = table->cellAt(block.position()); + if (tableRow < cell.row()) { + if (tableRow == 0) { + m_stream << Newline; + for (int col = 0; col < tableColumnWidths.length(); ++col) + m_stream << '|' << QString(tableColumnWidths[col], QLatin1Char('-')); + m_stream << '|'; + } + m_stream << Newline << "|"; + tableRow = cell.row(); + } + } else if (!block.textList()) { + if (lastWasList) + m_stream << Newline; + } + int endingCol = writeBlock(block, !table, table && tableRow == 0, + nextIsDifferent && !block.textList()); + m_doubleNewlineWritten = false; + if (table) { + QTextTableCell cell = table->cellAt(block.position()); + int paddingLen = -endingCol; + int spanEndCol = cell.column() + cell.columnSpan(); + for (int col = cell.column(); col < spanEndCol; ++col) + paddingLen += tableColumnWidths[col]; + if (paddingLen > 0) + m_stream << QString(paddingLen, Space); + for (int col = cell.column(); col < spanEndCol; ++col) + m_stream << "|"; + } else if (m_fencedCodeBlock && ending) { + m_stream << m_linePrefix << QString(m_wrappedLineIndent, Space) + << m_codeBlockFence << Newline << Newline; + m_codeBlockFence.clear(); + } else if (m_indentedCodeBlock && nextIsDifferent) { + m_stream << Newline; + } else if (endingCol > 0) { + if (block.textList() || block.blockFormat().hasProperty(QTextFormat::BlockCodeLanguage)) { + m_stream << Newline; + } else { + m_stream << Newline << Newline; + m_doubleNewlineWritten = true; + } + } + lastWasList = block.textList(); + } + child = iterator.currentFrame(); + ++iterator; + } + if (table) { + m_stream << Newline << Newline; + m_doubleNewlineWritten = true; + } + m_listInfo.clear(); +} + +QTextMarkdownWriter::ListInfo QTextMarkdownWriter::listInfo(QTextList *list) +{ + if (!m_listInfo.contains(list)) { + // decide whether this list is loose or tight + ListInfo info; + info.loose = false; + if (list->count() > 1) { + QTextBlock first = list->item(0); + QTextBlock last = list->item(list->count() - 1); + QTextBlock next = first.next(); + while (next.isValid()) { + if (next == last) + break; + qCDebug(lcMDW) << "next block in list" << list << next.text() << "part of list?" << next.textList(); + if (!next.textList()) { + // If we find a continuation paragraph, this list is "loose" + // because it will need a blank line to separate that paragraph. + qCDebug(lcMDW) << "decided list beginning with" << first.text() << "is loose after" << next.text(); + info.loose = true; + break; + } + next = next.next(); + } + } + m_listInfo.insert(list, info); + return info; + } + return m_listInfo.value(list); +} + +static int nearestWordWrapIndex(const QString &s, int before) +{ + before = qMin(before, s.length()); + int fragBegin = qMax(before - 15, 0); + if (lcMDW().isDebugEnabled()) { + QString frag = s.mid(fragBegin, 30); + qCDebug(lcMDW) << frag << before; + qCDebug(lcMDW) << QString(before - fragBegin, Period) + QLatin1Char('<'); + } + for (int i = before - 1; i >= 0; --i) { + if (s.at(i).isSpace()) { + qCDebug(lcMDW) << QString(i - fragBegin, Period) + QLatin1Char('^') << i; + return i; + } + } + qCDebug(lcMDW, "not possible"); + return -1; +} + +static int adjacentBackticksCount(const QString &s) +{ + int start = -1, len = s.length(); + int ret = 0; + for (int i = 0; i < len; ++i) { + if (s.at(i) == Backtick) { + if (start < 0) + start = i; + } else if (start >= 0) { + ret = qMax(ret, i - start); + start = -1; + } + } + if (s.at(len - 1) == Backtick) + ret = qMax(ret, len - start); + return ret; +} + +static void maybeEscapeFirstChar(QString &s) +{ + QString sTrimmed = s.trimmed(); + if (sTrimmed.isEmpty()) + return; + char firstChar = sTrimmed.at(0).toLatin1(); + if (firstChar == '*' || firstChar == '+' || firstChar == '-') { + int i = s.indexOf(QLatin1Char(firstChar)); + s.insert(i, QLatin1Char('\\')); + } +} + +int QTextMarkdownWriter::writeBlock(const QTextBlock &block, bool wrap, bool ignoreFormat, bool ignoreEmpty) +{ + if (block.text().isEmpty() && ignoreEmpty) + return 0; + const int ColumnLimit = 80; + QTextBlockFormat blockFmt = block.blockFormat(); + bool missedBlankCodeBlockLine = false; + if (block.textList()) { // it's a list-item + auto fmt = block.textList()->format(); + const int listLevel = fmt.indent(); + const int number = block.textList()->itemNumber(block) + 1; + QByteArray bullet = " "; + bool numeric = false; + switch (fmt.style()) { + case QTextListFormat::ListDisc: + bullet = "-"; + m_wrappedLineIndent = 2; + break; + case QTextListFormat::ListCircle: + bullet = "*"; + m_wrappedLineIndent = 2; + break; + case QTextListFormat::ListSquare: + bullet = "+"; + m_wrappedLineIndent = 2; + break; + case QTextListFormat::ListStyleUndefined: break; + case QTextListFormat::ListDecimal: + case QTextListFormat::ListLowerAlpha: + case QTextListFormat::ListUpperAlpha: + case QTextListFormat::ListLowerRoman: + case QTextListFormat::ListUpperRoman: + numeric = true; + m_wrappedLineIndent = 4; + break; + } + switch (blockFmt.marker()) { + case QTextBlockFormat::MarkerType::Checked: + bullet += " [x]"; + break; + case QTextBlockFormat::MarkerType::Unchecked: + bullet += " [ ]"; + break; + default: + break; + } + int indentFirstLine = (listLevel - 1) * (numeric ? 4 : 2); + m_wrappedLineIndent += indentFirstLine; + if (m_lastListIndent != listLevel && !m_doubleNewlineWritten && listInfo(block.textList()).loose) + m_stream << Newline; + m_lastListIndent = listLevel; + QString prefix(indentFirstLine, Space); + if (numeric) { + QString suffix = fmt.numberSuffix(); + if (suffix.isEmpty()) + suffix = QString(Period); + QString numberStr = QString::number(number) + suffix + Space; + if (numberStr.length() == 3) + numberStr += Space; + prefix += numberStr; + } else { + prefix += QLatin1String(bullet) + Space; + } + m_stream << prefix; + } else if (blockFmt.hasProperty(QTextFormat::BlockTrailingHorizontalRulerWidth)) { + m_stream << "- - -\n"; // unambiguous horizontal rule, not an underline under a heading + return 0; + } else if (blockFmt.hasProperty(QTextFormat::BlockCodeFence) || blockFmt.stringProperty(QTextFormat::BlockCodeLanguage).length() > 0) { + // It's important to preserve blank lines in code blocks. But blank lines in code blocks + // inside block quotes are getting preserved anyway (along with the "> " prefix). + if (!blockFmt.hasProperty(QTextFormat::BlockQuoteLevel)) + missedBlankCodeBlockLine = true; // only if we don't get any fragments below + if (!m_fencedCodeBlock) { + QString fenceChar = blockFmt.stringProperty(QTextFormat::BlockCodeFence); + if (fenceChar.isEmpty()) + fenceChar = QLatin1String("`"); + m_codeBlockFence = QString(3, fenceChar.at(0)); + // A block quote can contain an indented code block, but not vice-versa. + m_stream << m_linePrefix << QString(m_wrappedLineIndent, Space) << m_codeBlockFence + << Space << blockFmt.stringProperty(QTextFormat::BlockCodeLanguage) << Newline; + m_fencedCodeBlock = true; + } + } else if (!blockFmt.indent()) { + if (m_fencedCodeBlock) { + m_stream << m_linePrefix << QString(m_wrappedLineIndent, Space) + << m_codeBlockFence << Newline; + m_fencedCodeBlock = false; + m_codeBlockFence.clear(); + } + m_wrappedLineIndent = 0; + m_linePrefix.clear(); + if (blockFmt.hasProperty(QTextFormat::BlockQuoteLevel)) { + int level = blockFmt.intProperty(QTextFormat::BlockQuoteLevel); + QString quoteMarker = QStringLiteral("> "); + m_linePrefix.reserve(level * 2); + for (int i = 0; i < level; ++i) + m_linePrefix += quoteMarker; + } + if (blockFmt.hasProperty(QTextFormat::BlockCodeLanguage)) { + // A block quote can contain an indented code block, but not vice-versa. + m_linePrefix += QString(4, Space); + m_indentedCodeBlock = true; + } + } + if (blockFmt.headingLevel()) + m_stream << QByteArray(blockFmt.headingLevel(), '#') << ' '; + else + m_stream << m_linePrefix; + + QString wrapIndentString = m_linePrefix + QString(m_wrappedLineIndent, Space); + // It would be convenient if QTextStream had a lineCharPos() accessor, + // to keep track of how many characters (not bytes) have been written on the current line, + // but it doesn't. So we have to keep track with this col variable. + int col = wrapIndentString.length(); + bool mono = false; + bool startsOrEndsWithBacktick = false; + bool bold = false; + bool italic = false; + bool underline = false; + bool strikeOut = false; + QString backticks(Backtick); + for (QTextBlock::Iterator frag = block.begin(); !frag.atEnd(); ++frag) { + missedBlankCodeBlockLine = false; + QString fragmentText = frag.fragment().text(); + while (fragmentText.endsWith(Newline)) + fragmentText.chop(1); + if (block.textList()) { // <li>first line</br>continuation</li> + QString newlineIndent = QString(Newline) + QString(m_wrappedLineIndent, Space); + fragmentText.replace(QString(LineBreak), newlineIndent); + } else if (blockFmt.indent() > 0) { // <li>first line<p>continuation</p></li> + m_stream << QString(m_wrappedLineIndent, Space); + } else { + fragmentText.replace(LineBreak, Newline); + } + startsOrEndsWithBacktick |= fragmentText.startsWith(Backtick) || fragmentText.endsWith(Backtick); + QTextCharFormat fmt = frag.fragment().charFormat(); + if (fmt.isImageFormat()) { + QTextImageFormat ifmt = fmt.toImageFormat(); + QString desc = ifmt.stringProperty(QTextFormat::ImageAltText); + if (desc.isEmpty()) + desc = QLatin1String("image"); + QString s = QLatin1String("![") + desc + QLatin1String("](") + ifmt.name(); + QString title = ifmt.stringProperty(QTextFormat::ImageTitle); + if (!title.isEmpty()) + s += Space + DoubleQuote + title + DoubleQuote; + s += QLatin1Char(')'); + if (wrap && col + s.length() > ColumnLimit) { + m_stream << Newline << wrapIndentString; + col = m_wrappedLineIndent; + } + m_stream << s; + col += s.length(); + } else if (fmt.hasProperty(QTextFormat::AnchorHref)) { + QString s = QLatin1Char('[') + fragmentText + QLatin1String("](") + + fmt.property(QTextFormat::AnchorHref).toString() + QLatin1Char(')'); + if (wrap && col + s.length() > ColumnLimit) { + m_stream << Newline << wrapIndentString; + col = m_wrappedLineIndent; + } + m_stream << s; + col += s.length(); + } else { + QFontInfo fontInfo(fmt.font()); + bool monoFrag = fontInfo.fixedPitch(); + QString markers; + if (!ignoreFormat) { + if (monoFrag != mono && !m_indentedCodeBlock && !m_fencedCodeBlock) { + if (monoFrag) + backticks = QString(adjacentBackticksCount(fragmentText) + 1, Backtick); + markers += backticks; + if (startsOrEndsWithBacktick) + markers += Space; + mono = monoFrag; + } + if (!blockFmt.headingLevel() && !mono) { + if (fontInfo.bold() != bold) { + markers += QLatin1String("**"); + bold = fontInfo.bold(); + } + if (fontInfo.italic() != italic) { + markers += QLatin1Char('*'); + italic = fontInfo.italic(); + } + if (fontInfo.strikeOut() != strikeOut) { + markers += QLatin1String("~~"); + strikeOut = fontInfo.strikeOut(); + } + if (fontInfo.underline() != underline) { + // Markdown doesn't support underline, but the parser will treat a single underline + // the same as a single asterisk, and the marked fragment will be rendered in italics. + // That will have to do. + markers += QLatin1Char('_'); + underline = fontInfo.underline(); + } + } + } + if (wrap && col + markers.length() * 2 + fragmentText.length() > ColumnLimit) { + int i = 0; + int fragLen = fragmentText.length(); + bool breakingLine = false; + while (i < fragLen) { + if (col >= ColumnLimit) { + m_stream << Newline << wrapIndentString; + col = m_wrappedLineIndent; + while (fragmentText[i].isSpace()) + ++i; + } + int j = i + ColumnLimit - col; + if (j < fragLen) { + int wi = nearestWordWrapIndex(fragmentText, j); + if (wi < 0) { + j = fragLen; + } else if (wi >= i) { + j = wi; + breakingLine = true; + } + } else { + j = fragLen; + breakingLine = false; + } + QString subfrag = fragmentText.mid(i, j - i); + if (!i) { + m_stream << markers; + col += markers.length(); + } + if (col == m_wrappedLineIndent) + maybeEscapeFirstChar(subfrag); + m_stream << subfrag; + if (breakingLine) { + m_stream << Newline << wrapIndentString; + col = m_wrappedLineIndent; + } else { + col += subfrag.length(); + } + i = j + 1; + } + } else { + m_stream << markers << fragmentText; + col += markers.length() + fragmentText.length(); + } + } + } + if (mono) { + if (startsOrEndsWithBacktick) { + m_stream << Space; + col += 1; + } + m_stream << backticks; + col += backticks.size(); + } + if (bold) { + m_stream << "**"; + col += 2; + } + if (italic) { + m_stream << "*"; + col += 1; + } + if (underline) { + m_stream << "_"; + col += 1; + } + if (strikeOut) { + m_stream << "~~"; + col += 2; + } + if (missedBlankCodeBlockLine) + m_stream << Newline; + return col; +} + +QT_END_NAMESPACE |