Add QTextDocFragment::to/fromMarkdown() & QTextCursor::insertMarkdown()

Also add the beginnings of an autotest for QTextCursor::insertHtml(),
for comparison purposes.

We can see that the block to be inserted is merged with an existing
block by default rather than being inserted as a new one, with both HTML and
Markdown insertions.  So now we test for leading and trailing newlines
in the markdown to be inserted, to determine whether we need a new block
into which to insert, and to "hit enter" at the end of the insertion.

QSKIP the toMarkdown() comparisons if GeneralFont is mono. This happens
on Boot2Qt systems in CI.

Task-number: QTBUG-76105
Task-number: QTBUG-94462
Task-number: QTBUG-100515
Task-number: QTBUG-103484
Change-Id: I51a05c6a7cd0be4f2817f4a922f45fa663982293
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

5 files changed, 310 insertions, 6 deletions

diff --git a/src/gui/text/qtextcursor.cpp b/src/gui/text/qtextcursor.cpp
index 8a8b2efaef..1480020410 100644
--- a/src/gui/text/qtextcursor.cpp
+++ b/src/gui/text/qtextcursor.cpp
@@ -2291,6 +2291,28 @@ void QTextCursor::insertHtml(const QString &html)
 #endif // QT_NO_TEXTHTMLPARSER
 
 /*!
+    \since 6.4
+    Inserts the \a markdown text at the current position(),
+    with the specified Markdown \a features. The default is GitHub dialect.
+*/
+
+#if QT_CONFIG(textmarkdownreader)
+
+void QTextCursor::insertMarkdown(const QString &markdown, QTextDocument::MarkdownFeatures features)
+{
+    if (!d || !d->priv)
+        return;
+    QTextDocumentFragment fragment = QTextDocumentFragment::fromMarkdown(markdown, features);
+    if (markdown.startsWith(QLatin1Char('\n')))
+        insertBlock(fragment.d->doc->firstBlock().blockFormat());
+    insertFragment(fragment);
+    if (!atEnd() && markdown.endsWith(QLatin1Char('\n')))
+        insertText(QLatin1String("\n"));
+}
+
+#endif // textmarkdownreader
+
+/*!
     \overload
     \since 4.2
 
diff --git a/src/gui/text/qtextcursor.h b/src/gui/text/qtextcursor.h
index b33b05aacc..890712ab22 100644
--- a/src/gui/text/qtextcursor.h
+++ b/src/gui/text/qtextcursor.h
@@ -43,12 +43,11 @@
 #include <QtGui/qtguiglobal.h>
 #include <QtCore/qstring.h>
 #include <QtCore/qshareddata.h>
+#include <QtGui/qtextdocument.h>
 #include <QtGui/qtextformat.h>
 
 QT_BEGIN_NAMESPACE
 
-
-class QTextDocument;
 class QTextCursorPrivate;
 class QTextDocumentFragment;
 class QTextCharFormat;
@@ -201,6 +200,10 @@ public:
 #ifndef QT_NO_TEXTHTMLPARSER
     void insertHtml(const QString &html);
 #endif // QT_NO_TEXTHTMLPARSER
+#if QT_CONFIG(textmarkdownreader)
+    void insertMarkdown(const QString &markdown,
+                        QTextDocument::MarkdownFeatures features = QTextDocument::MarkdownDialectGitHub);
+#endif // textmarkdownreader
 
     void insertImage(const QTextImageFormat &format, QTextFrameFormat::Position alignment);
     void insertImage(const QTextImageFormat &format);
diff --git a/src/gui/text/qtextdocumentfragment.cpp b/src/gui/text/qtextdocumentfragment.cpp
index 348916dd04..47baa4229e 100644
--- a/src/gui/text/qtextdocumentfragment.cpp
+++ b/src/gui/text/qtextdocumentfragment.cpp
@@ -41,6 +41,12 @@
 #include "qtextdocumentfragment_p.h"
 #include "qtextcursor_p.h"
 #include "qtextlist.h"
+#if QT_CONFIG(textmarkdownreader)
+#include "qtextmarkdownimporter_p.h"
+#endif
+#if QT_CONFIG(textmarkdownwriter)
+#include "qtextmarkdownwriter_p.h"
+#endif
 
 #include <qdebug.h>
 #include <qbytearray.h>
@@ -412,6 +418,26 @@ QString QTextDocumentFragment::toHtml() const
 
 #endif // QT_NO_TEXTHTMLPARSER
 
+#if QT_CONFIG(textmarkdownwriter)
+
+/*!
+    \since 6.4
+
+    Returns the contents of the document fragment as Markdown,
+    with the specified \a features. The default is GitHub dialect.
+
+    \sa toPlainText(), QTextDocument::toMarkdown()
+*/
+QString QTextDocumentFragment::toMarkdown(QTextDocument::MarkdownFeatures features) const
+{
+    if (!d)
+        return QString();
+
+    return d->doc->toMarkdown(features);
+}
+
+#endif // textmarkdownwriter
+
 /*!
     Returns a document fragment that contains the given \a plainText.
 
@@ -1277,9 +1303,6 @@ void QTextHtmlImporter::appendBlock(const QTextBlockFormat &format, QTextCharFor
         compressNextWhitespace = RemoveWhiteSpace;
 }
 
-#endif // QT_NO_TEXTHTMLPARSER
-
-#ifndef QT_NO_TEXTHTMLPARSER
 /*!
     \fn QTextDocumentFragment QTextDocumentFragment::fromHtml(const QString &text, const QTextDocument *resourceProvider)
     \since 4.2
@@ -1305,4 +1328,31 @@ QTextDocumentFragment QTextDocumentFragment::fromHtml(const QString &html, const
 
 #endif // QT_NO_TEXTHTMLPARSER
 
+#if QT_CONFIG(textmarkdownreader)
+
+/*!
+    \fn QTextDocumentFragment QTextDocumentFragment::fromMarkdown(const QString &markdown, QTextDocument::MarkdownFeatures features)
+    \since 6.4
+
+    Returns a QTextDocumentFragment based on the given \a markdown text with
+    the specified \a features. The default is GitHub dialect.
+
+    The formatting is preserved as much as possible; for example, \c {**bold**}
+    will become a document fragment containing the text "bold" with a bold
+    character style.
+
+    \note Loading external resources is not supported.
+*/
+QTextDocumentFragment QTextDocumentFragment::fromMarkdown(const QString &markdown, QTextDocument::MarkdownFeatures features)
+{
+    QTextDocumentFragment res;
+    res.d = new QTextDocumentFragmentPrivate;
+
+    QTextMarkdownImporter importer(features);
+    importer.import(res.d->doc, markdown);
+    return res;
+}
+
+#endif // textmarkdownreader
+
 QT_END_NAMESPACE
diff --git a/src/gui/text/qtextdocumentfragment.h b/src/gui/text/qtextdocumentfragment.h
index 37d7006ae6..3c23e403e0 100644
--- a/src/gui/text/qtextdocumentfragment.h
+++ b/src/gui/text/qtextdocumentfragment.h
@@ -41,13 +41,13 @@
 #define QTEXTDOCUMENTFRAGMENT_H
 
 #include <QtGui/qtguiglobal.h>
+#include <QtGui/qtextdocument.h>
 #include <QtCore/qstring.h>
 
 QT_BEGIN_NAMESPACE
 
 
 class QTextStream;
-class QTextDocument;
 class QTextDocumentFragmentPrivate;
 class QTextCursor;
 
@@ -68,11 +68,18 @@ public:
 #ifndef QT_NO_TEXTHTMLPARSER
     QString toHtml() const;
 #endif // QT_NO_TEXTHTMLPARSER
+#if QT_CONFIG(textmarkdownwriter)
+    QString toMarkdown(QTextDocument::MarkdownFeatures features = QTextDocument::MarkdownDialectGitHub) const;
+#endif
 
     static QTextDocumentFragment fromPlainText(const QString &plainText);
 #ifndef QT_NO_TEXTHTMLPARSER
     static QTextDocumentFragment fromHtml(const QString &html, const QTextDocument *resourceProvider = nullptr);
 #endif // QT_NO_TEXTHTMLPARSER
+#if QT_CONFIG(textmarkdownreader)
+    static QTextDocumentFragment fromMarkdown(const QString &markdown,
+                                              QTextDocument::MarkdownFeatures features = QTextDocument::MarkdownDialectGitHub);
+#endif
 
 private:
     QTextDocumentFragmentPrivate *d;
diff --git a/tests/auto/gui/text/qtextcursor/tst_qtextcursor.cpp b/tests/auto/gui/text/qtextcursor/tst_qtextcursor.cpp
index 17d2336b74..cea80efc3b 100644
--- a/tests/auto/gui/text/qtextcursor/tst_qtextcursor.cpp
+++ b/tests/auto/gui/text/qtextcursor/tst_qtextcursor.cpp
@@ -28,7 +28,9 @@
 
 
 #include <QTest>
+#include <QLoggingCategory>
 
+#include <qfontinfo.h>
 #include <qtextdocument.h>
 #include <qtexttable.h>
 #include <qvariant.h>
@@ -41,6 +43,8 @@
 
 #include <private/qtextcursor_p.h>
 
+Q_LOGGING_CATEGORY(lcTests, "qt.gui.tests")
+
 QT_FORWARD_DECLARE_CLASS(QTextDocument)
 
 class tst_QTextCursor : public QObject
@@ -110,6 +114,14 @@ private slots:
     void selectVisually();
 
     void insertText();
+#ifndef QT_NO_TEXTHTMLPARSER
+    void insertHtml_data();
+    void insertHtml();
+#endif
+#if QT_CONFIG(textmarkdownreader)
+    void insertMarkdown_data();
+    void insertMarkdown();
+#endif
 
     void insertFragmentShouldUseCurrentCharFormat();
 
@@ -1428,6 +1440,216 @@ void tst_QTextCursor::insertText()
     QCOMPARE(cursor.block().text(), QString("yoyodyne"));
 }
 
+
+#ifndef QT_NO_TEXTHTMLPARSER
+
+void tst_QTextCursor::insertHtml_data()
+{
+    QTest::addColumn<QString>("initialText");
+    QTest::addColumn<int>("expectedInitialBlockCount");
+    QTest::addColumn<bool>("insertBlock");
+    QTest::addColumn<bool>("insertAsPlainText");
+    QTest::addColumn<int>("insertPosition");
+    QTest::addColumn<QString>("insertText");
+    QTest::addColumn<QString>("expectedSelText");
+    QTest::addColumn<QString>("expectedText");
+    QTest::addColumn<QString>("expectedMarkdown");
+
+    const QString htmlHeadingString("<h1>Hello World</h1>");
+
+    QTest::newRow("insert as html at end of heading")
+            << htmlHeadingString << 1
+            << false << false << 11 << QString("Other\ntext")
+            << QString("Hello WorldOther text")
+            << QString("Hello WorldOther text")
+            << QString("# Hello WorldOther text\n\n");
+
+    QTest::newRow("insert as html in new block at end of heading")
+            << htmlHeadingString << 1
+            << false << true << 11 << QString("Other\ntext")
+            << QString("Hello WorldOther\u2029text")
+            << QString("Hello WorldOther\ntext")
+            << QString("# Hello WorldOther\n\n# text\n\n");
+
+    QTest::newRow("insert as html in middle of heading")
+            << htmlHeadingString << 1
+            << false << false << 6 << QString("\n\nOther\ntext\n\n")
+            << QString("Hello Other text World")
+            << QString("Hello Other text World")
+            << QString("# Hello Other text World\n\n");
+
+    QTest::newRow("insert as text at end of heading")
+            << htmlHeadingString << 1
+            << true << false << 11 << QString("\n\nOther\ntext")
+            << QString("Hello World\u2029Other text")
+            << QString("Hello World\nOther text")
+            << QString("# Hello World\n\nOther text\n\n");
+
+    QTest::newRow("insert as text in new block at end of heading")
+            << htmlHeadingString << 1
+            << true << true << 11 << QString("\n\nOther\ntext")
+            << QString("Hello World\u2029\u2029\u2029Other\u2029text")
+            << QString("Hello World\n\n\nOther\ntext")
+            << QString("# Hello World\n\n**Other**\n\n**text**\n\n");
+
+    QTest::newRow("insert as text in middle of heading")
+            << htmlHeadingString << 1
+            << true << false << 6 << QString("Other\ntext")
+            << QString("Hello \u2029Other textWorld")
+            << QString("Hello \nOther textWorld")
+            << QString("# Hello \n\nOther text**World**\n\n");
+}
+
+void tst_QTextCursor::insertHtml()
+{
+    QFETCH(QString, initialText);
+    QFETCH(int, expectedInitialBlockCount);
+    QFETCH(bool, insertBlock);
+    QFETCH(bool, insertAsPlainText);
+    QFETCH(int, insertPosition);
+    QFETCH(QString, insertText);
+    QFETCH(QString, expectedSelText);
+    QFETCH(QString, expectedText);
+    QFETCH(QString, expectedMarkdown);
+
+    cursor.insertHtml(initialText);
+    QCOMPARE(blockCount(), expectedInitialBlockCount);
+    cursor.setPosition(insertPosition);
+    if (insertBlock)
+        cursor.insertBlock(QTextBlockFormat());
+    qCDebug(lcTests) << "pos" << cursor.position() << "block" << cursor.blockNumber()
+                     << "heading" << cursor.blockFormat().headingLevel();
+    if (insertAsPlainText)
+        cursor.insertText(insertText);
+    else
+        cursor.insertHtml(insertText);
+    cursor.select(QTextCursor::Document);
+    qCDebug(lcTests) << "sel text after insertion" << cursor.selectedText();
+    qCDebug(lcTests) << "text after insertion" << cursor.document()->toPlainText();
+    qCDebug(lcTests) << "html after insertion" << cursor.document()->toHtml();
+    qCDebug(lcTests) << "markdown after insertion" << cursor.document()->toMarkdown();
+    QCOMPARE(cursor.selectedText(), expectedSelText);
+    QCOMPARE(cursor.document()->toPlainText(), expectedText);
+    if (auto defaultFont = QFontDatabase::systemFont(QFontDatabase::GeneralFont); QFontInfo(defaultFont).fixedPitch()) {
+        qWarning() << defaultFont << "is QFontDatabase::GeneralFont, and is fixedPitch";
+        QSKIP("cannot reliably distinguish normal and monospace markdown spans on this system (QTBUG-103484)");
+    }
+    QCOMPARE(cursor.document()->toMarkdown(), expectedMarkdown);
+}
+
+#endif // QT_NO_TEXTHTMLPARSER
+
+#if QT_CONFIG(textmarkdownreader)
+
+void tst_QTextCursor::insertMarkdown_data()
+{
+    QTest::addColumn<QString>("initialText");
+    QTest::addColumn<int>("expectedInitialBlockCount");
+    QTest::addColumn<int>("insertPosition");
+    QTest::addColumn<QString>("insertText");
+    QTest::addColumn<QString>("expectedSelText");
+    QTest::addColumn<QString>("expectedText");
+    QTest::addColumn<QString>("expectedMarkdown");
+
+    QTest::newRow("bold fragment in italic span")
+            << "someone said *hello world*" << 1
+            << 19 << QString(" **crazy** ")
+            << QString("someone said hello crazyworld")
+            << QString("someone said hello crazyworld")
+            << QString("someone said *hello ***crazy***world*\n\n"); // explicit B+I: not necessary but OK
+
+    QTest::newRow("list in a paragraph")
+            << "hello list with 3 items" << 1
+            << 10 << QString("1. one\n2. two\n")
+            << QString("hello list\u2029one\u2029two\u2029 with 3 items")
+            << QString("hello list\none\ntwo\n with 3 items")
+            << QString("hello list\n\n1.  one\n2.  two\n3.   with 3 items\n");
+
+    QTest::newRow("list in a list")
+            << "1) bread\n2) milk\n" << 2
+            << 6 << QString("0) eggs\n1) maple syrup\n")
+            << QString("bread\u2029eggs\u2029maple syrup\u2029milk")
+            << QString("bread\neggs\nmaple syrup\nmilk")
+            << QString("1)  bread\n2)  eggs\n1)  maple syrup\n2)  milk\n");
+            // renumbering would happen if we re-read the whole document
+
+    QTest::newRow("list after a list")
+            << "1) bread\n2) milk\n\n" << 2
+            << 13 << QString("\n0) eggs\n1) maple syrup\n")
+            << QString("bread\u2029milk\u2029eggs\u2029maple syrup")
+            << QString("bread\nmilk\neggs\nmaple syrup")
+            << QString("1)  bread\n2)  milk\n3)  eggs\n1)  maple syrup\n");
+
+    const QString markdownHeadingString("# Hello\nWorld\n");
+
+    QTest::newRow("markdown heading at end of markdown heading")
+            << markdownHeadingString << 2
+            << 11 << QString("\n\n## Other text")
+            << QString("Hello\u2029World\u2029Other text")
+            << QString("Hello\nWorld\nOther text")
+            << QString("# Hello\n\nWorld\n\n## Other text\n\n");
+
+    QTest::newRow("markdown heading into middle of markdown heading")
+            << markdownHeadingString << 2
+            << 6 << QString("## Other\ntext\n\n")
+            << QString("Hello\u2029Other\u2029text\u2029World")
+            << QString("Hello\nOther\ntext\nWorld")
+            << QString("# Hello\n\n**Other**\n\ntext\n\nWorld\n\n");
+
+    QTest::newRow("markdown heading without trailing newline into middle of markdown heading")
+            << markdownHeadingString << 2
+            << 6 << QString("## Other\ntext")
+            << QString("Hello\u2029Other\u2029textWorld")
+            << QString("Hello\nOther\ntextWorld")
+            << QString("# Hello\n\n**Other**\n\ntextWorld\n\n");
+
+    QTest::newRow("text into middle of markdown heading after newline")
+            << markdownHeadingString << 2
+            << 6 << QString("Other ")
+            << QString("Hello\u2029OtherWorld")
+            << QString("Hello\nOtherWorld")
+            << QString("# Hello\n\nOtherWorld\n\n");
+
+    QTest::newRow("text into middle of markdown heading before newline")
+            << markdownHeadingString << 2
+            << 5 << QString(" Other ")
+            << QString("HelloOther\u2029World")
+            << QString("HelloOther\nWorld")
+            << QString("# HelloOther\n\nWorld\n\n");
+}
+
+void tst_QTextCursor::insertMarkdown()
+{
+    QFETCH(QString, initialText);
+    QFETCH(int, expectedInitialBlockCount);
+    QFETCH(int, insertPosition);
+    QFETCH(QString, insertText);
+    QFETCH(QString, expectedSelText);
+    QFETCH(QString, expectedText);
+    QFETCH(QString, expectedMarkdown);
+
+    cursor.insertMarkdown(initialText);
+    QCOMPARE(blockCount(), expectedInitialBlockCount);
+    cursor.setPosition(insertPosition);
+    qCDebug(lcTests) << "pos" << cursor.position() << "block" << cursor.blockNumber()
+                     << "heading" << cursor.blockFormat().headingLevel();
+    cursor.insertMarkdown(insertText);
+    cursor.select(QTextCursor::Document);
+    qCDebug(lcTests) << "sel text after insertion" << cursor.selectedText();
+    qCDebug(lcTests) << "text after insertion" << cursor.document()->toPlainText();
+    qCDebug(lcTests) << "html after insertion" << cursor.document()->toHtml();
+    qCDebug(lcTests) << "markdown after insertion" << cursor.document()->toMarkdown();
+    QCOMPARE(cursor.selectedText(), expectedSelText);
+    QCOMPARE(cursor.document()->toPlainText(), expectedText);
+    if (auto defaultFont = QFontDatabase::systemFont(QFontDatabase::GeneralFont); QFontInfo(defaultFont).fixedPitch()) {
+        qWarning() << defaultFont << "is QFontDatabase::GeneralFont, and is fixedPitch";
+        QSKIP("cannot reliably distinguish normal and monospace markdown spans on this system (QTBUG-103484)");
+    }
+    QCOMPARE(cursor.document()->toMarkdown(), expectedMarkdown);
+}
+
+#endif // textmarkdownreader
+
 void tst_QTextCursor::insertFragmentShouldUseCurrentCharFormat()
 {
     QTextDocumentFragment fragment = QTextDocumentFragment::fromPlainText("Hello World");