Overload QTextBrowser::setSource() to add optional type argument

Now that it's trying to guess whether the type is markdown based on
the file extension, there needs to be a way to override it. For example
it might be arranged that directory listings will be generated in
markdown format instead of HTML; then when loading a source URL that
is a directory, the application may override the type. The type for
the single-argument setSource(url) is UnknownResource to preserve
the existing behavior, but the user can override the guessing by
setting a specific type.

Change-Id: Id111efd24de7d8fd18c47b16a2d58f5b09d77891
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

src/gui/text/qtextdocument.h

@@ -225,6 +225,7 @@ public:
     void print(QPagedPaintDevice *printer) const;
 
     enum ResourceType {
+        UnknownResource = 0,
         HtmlResource  = 1,
         ImageResource = 2,
         StyleSheetResource = 3,
@@ -232,6 +233,7 @@ public:
 
         UserResource  = 100
     };
+    Q_ENUM(ResourceType)
 
     QVariant resource(int type, const QUrl &name) const;
     void addResource(int type, const QUrl &name, const QVariant &resource);

src/widgets/widgets/qtextbrowser.cpp

@@ -86,6 +86,7 @@ public:
         int hpos;
         int vpos;
         int focusIndicatorPosition, focusIndicatorAnchor;
+        QTextDocument::ResourceType type = QTextDocument::UnknownResource;
     };
 
     HistoryEntry history(int i) const
@@ -122,6 +123,8 @@ public:
     bool openExternalLinks;
     bool openLinks;
 
+    QTextDocument::ResourceType currentType;
+
 #ifndef QT_NO_CURSOR
     QCursor oldCursor;
 #endif
@@ -137,7 +140,7 @@ public:
     void _q_activateAnchor(const QString &href);
     void _q_highlightLink(const QString &href);
 
-    void setSource(const QUrl &url);
+    void setSource(const QUrl &url, QTextDocument::ResourceType type);
 
     // re-imlemented from QTextEditPrivate
     virtual QUrl resolveUrl(const QUrl &url) const override;
@@ -274,7 +277,7 @@ void QTextBrowserPrivate::_q_highlightLink(const QString &anchor)
     }
 }
 
-void QTextBrowserPrivate::setSource(const QUrl &url)
+void QTextBrowserPrivate::setSource(const QUrl &url, QTextDocument::ResourceType type)
 {
     Q_Q(QTextBrowser);
 #ifndef QT_NO_CURSOR
@@ -291,14 +294,18 @@ void QTextBrowserPrivate::setSource(const QUrl &url)
     currentUrlWithoutFragment.setFragment(QString());
     QUrl newUrlWithoutFragment = currentURL.resolved(url);
     newUrlWithoutFragment.setFragment(QString());
-    QTextDocument::ResourceType type = QTextDocument::HtmlResource;
     QString fileName = url.fileName();
+    if (type == QTextDocument::UnknownResource) {
 #if QT_CONFIG(textmarkdownreader)
-    if (fileName.endsWith(QLatin1String(".md")) ||
-            fileName.endsWith(QLatin1String(".mkd")) ||
-            fileName.endsWith(QLatin1String(".markdown")))
-        type = QTextDocument::MarkdownResource;
+        if (fileName.endsWith(QLatin1String(".md")) ||
+                fileName.endsWith(QLatin1String(".mkd")) ||
+                fileName.endsWith(QLatin1String(".markdown")))
+            type = QTextDocument::MarkdownResource;
+        else
 #endif
+            type = QTextDocument::HtmlResource;
+    }
+    currentType = type;
 
     if (url.isValid()
         && (newUrlWithoutFragment != currentUrlWithoutFragment || forceLoadOnSourceChange)) {
@@ -574,6 +581,7 @@ QTextBrowserPrivate::HistoryEntry QTextBrowserPrivate::createHistoryEntry() cons
 {
     HistoryEntry entry;
     entry.url = q_func()->source();
+    entry.type = q_func()->sourceType();
     entry.title = q_func()->documentTitle();
     entry.hpos = hbar->value();
     entry.vpos = vbar->value();
@@ -590,7 +598,7 @@ QTextBrowserPrivate::HistoryEntry QTextBrowserPrivate::createHistoryEntry() cons
 
 void QTextBrowserPrivate::restoreHistoryEntry(const HistoryEntry &entry)
 {
-    setSource(entry.url);
+    setSource(entry.url, entry.type);
     hbar->setValue(entry.hpos);
     vbar->setValue(entry.vpos);
     if (entry.focusIndicatorAnchor != -1 && entry.focusIndicatorPosition != -1) {
@@ -732,7 +740,13 @@ QTextBrowser::~QTextBrowser()
     document is displayed as a popup rather than as new document in
     the browser window itself. Otherwise, the document is displayed
     normally in the text browser with the text set to the contents of
-    the named document with setHtml().
+    the named document with \l QTextDocument::setHtml() or
+    \l QTextDocument::setMarkdown(), depending on whether the filename ends
+    with any of the known Markdown file extensions.
+
+    If you would like to avoid automatic type detection
+    and specify the type explicitly, call setSource() rather than
+    setting this property.
 
     By default, this property contains an empty URL.
 */
@@ -745,6 +759,23 @@ QUrl QTextBrowser::source() const
         return d->stack.top().url;
 }
 
+/*!
+    \property QTextBrowser::sourceType
+    \brief the type of the displayed document
+
+    This is QTextDocument::UnknownResource if no document is displayed or if
+    the type of the source is unknown. Otherwise it holds the type that was
+    detected, or the type that was specified when setSource() was called.
+*/
+QTextDocument::ResourceType QTextBrowser::sourceType() const
+{
+    Q_D(const QTextBrowser);
+    if (d->stack.isEmpty())
+        return QTextDocument::UnknownResource;
+    else
+        return d->stack.top().type;
+}
+
 /*!
     \property QTextBrowser::searchPaths
     \brief the search paths used by the text browser to find supporting
@@ -775,16 +806,46 @@ void QTextBrowser::reload()
     Q_D(QTextBrowser);
     QUrl s = d->currentURL;
     d->currentURL = QUrl();
-    setSource(s);
+    setSource(s, d->currentType);
 }
 
+#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
 void QTextBrowser::setSource(const QUrl &url)
+{
+    setSource(url, QTextDocument::UnknownResource);
+}
+#endif
+
+/*!
+    Attempts to load the document at the given \a url with the specified \a type.
+
+    If \a type is \l {QTextDocument::ResourceType::UnknownResource}{UnknownResource}
+    (the default), the document type will be detected: that is, if the url ends
+    with an extension of \c{.md}, \c{.mkd} or \c{.markdown}, the document will be
+    loaded via \l QTextDocument::setMarkdown(); otherwise it will be loaded via
+    \l QTextDocument::setHtml(). This detection can be bypassed by specifying
+    the \a type explicitly.
+*/
+void QTextBrowser::setSource(const QUrl &url, QTextDocument::ResourceType type)
+{
+    doSetSource(url, type);
+}
+
+#if QT_VERSION >= QT_VERSION_CHECK(6,0,0)
+/*!
+    Attempts to load the document at the given \a url with the specified \a type.
+
+    setSource() calls doSetSource.  In Qt 5, setSource(const QUrl &url) was virtual.
+    In Qt 6, doSetSource() is virtual instead, so that it can be overridden in subclasses.
+*/
+#endif
+void QTextBrowser::doSetSource(const QUrl &url, QTextDocument::ResourceType type)
 {
     Q_D(QTextBrowser);
 
     const QTextBrowserPrivate::HistoryEntry historyEntry = d->createHistoryEntry();
 
-    d->setSource(url);
+    d->setSource(url, type);
 
     if (!url.isValid())
         return;
@@ -798,6 +859,7 @@ void QTextBrowser::setSource(const QUrl &url)
 
     QTextBrowserPrivate::HistoryEntry entry;
     entry.url = url;
+    entry.type = d->currentType;
     entry.title = documentTitle();
     entry.hpos = 0;
     entry.vpos = 0;

src/widgets/widgets/qtextbrowser.h

@@ -55,6 +55,7 @@ class Q_WIDGETS_EXPORT QTextBrowser : public QTextEdit
     Q_OBJECT
 
     Q_PROPERTY(QUrl source READ source WRITE setSource)
+    Q_PROPERTY(QTextDocument::ResourceType sourceType READ sourceType)
     Q_OVERRIDE(bool modified SCRIPTABLE false)
     Q_OVERRIDE(bool readOnly DESIGNABLE false SCRIPTABLE false)
     Q_OVERRIDE(bool undoRedoEnabled DESIGNABLE false SCRIPTABLE false)
@@ -67,6 +68,7 @@ public:
     virtual ~QTextBrowser();
 
     QUrl source() const;
+    QTextDocument::ResourceType sourceType() const;
 
     QStringList searchPaths() const;
     void setSearchPaths(const QStringList &paths);
@@ -88,7 +90,12 @@ public:
     void setOpenLinks(bool open);
 
 public Q_SLOTS:
+#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
     virtual void setSource(const QUrl &name);
+    void setSource(const QUrl &name, QTextDocument::ResourceType type);
+#else
+    void setSource(const QUrl &name, QTextDocument::ResourceType type = QTextDocument::UnknownResource);
+#endif
     virtual void backward();
     virtual void forward();
     virtual void home();
@@ -112,6 +119,10 @@ protected:
     virtual void focusOutEvent(QFocusEvent *ev) override;
     virtual bool focusNextPrevChild(bool next) override;
     virtual void paintEvent(QPaintEvent *e) override;
+#if QT_VERSION >= QT_VERSION_CHECK(6,0,0)
+    virtual
+#endif
+    void doSetSource(const QUrl &name, QTextDocument::ResourceType type = QTextDocument::UnknownResource);
 
 private:
     Q_DISABLE_COPY(QTextBrowser)

tests/auto/widgets/widgets/qtextbrowser/heading.html

@@ -0,0 +1,2 @@
+<h3>this is a heading</h3>
+<p>this is a paragraph</p>

tests/auto/widgets/widgets/qtextbrowser/markdown.really

@@ -0,0 +1,2 @@
+### this is a heading
+this is a paragraph

tests/auto/widgets/widgets/qtextbrowser/qtextbrowser.pro

@@ -4,6 +4,6 @@ SOURCES += tst_qtextbrowser.cpp
 
 QT += widgets testlib
 
-TESTDATA += *.html *.md subdir/*
+TESTDATA += *.html *.md markdown.really subdir/*
 
 builtin_testdata: DEFINES += BUILTIN_TESTDATA

tests/auto/widgets/widgets/qtextbrowser/tst_qtextbrowser.cpp

@@ -92,7 +92,8 @@ private slots:
     void focusIndicator();
     void focusHistory();
     void urlEncoding();
-    void markdown();
+    void sourceType_data();
+    void sourceType();
 
 private:
     TestBrowser *browser;
@@ -679,19 +680,45 @@ void tst_QTextBrowser::urlEncoding()
     delete browser;
 }
 
-void tst_QTextBrowser::markdown()
+void tst_QTextBrowser::sourceType_data()
 {
-    browser->setSource(QUrl::fromLocalFile(QFINDTESTDATA("markdown.md")));
+    QTest::addColumn<QString>("sourceFile");
+    QTest::addColumn<QTextDocument::ResourceType>("sourceType");
+    QTest::addColumn<int>("expectedMaxHeadingLevel");
+    QTest::addColumn<QTextDocument::ResourceType>("expectedSourceType");
+
+#if QT_CONFIG(textmarkdownreader)
+    const int maxMdHeadingLevel = 3;
+    const QTextDocument::ResourceType mdExpectedType = QTextDocument::MarkdownResource;
+#else
+    // If Qt doesn't support markdown, and we read a MD document anyway, it won't have any H3's.
+    const int maxMdHeadingLevel = 0;
+    const QTextDocument::ResourceType mdExpectedType = QTextDocument::HtmlResource;
+#endif
+    QTest::newRow("markdown detected") << "markdown.md" << QTextDocument::UnknownResource << maxMdHeadingLevel << mdExpectedType;
+    QTest::newRow("markdown specified") << "markdown.really" << QTextDocument::MarkdownResource << maxMdHeadingLevel << mdExpectedType;
+    QTest::newRow("markdown not identified") << "markdown.really" << QTextDocument::UnknownResource << 0 << QTextDocument::HtmlResource;
+    QTest::newRow("html detected") << "heading.html" << QTextDocument::UnknownResource << 3 << QTextDocument::HtmlResource;
+    QTest::newRow("html specified") << "heading.html" << QTextDocument::HtmlResource << 3 << QTextDocument::HtmlResource;
+}
+
+void tst_QTextBrowser::sourceType()
+{
+    QFETCH(QString, sourceFile);
+    QFETCH(QTextDocument::ResourceType, sourceType);
+    QFETCH(int, expectedMaxHeadingLevel);
+    QFETCH(QTextDocument::ResourceType, expectedSourceType);
+    if (sourceType == QTextDocument::UnknownResource)
+        // verify that the property setter works, with its default parameter for sourceType
+        browser->setProperty("source", QUrl::fromLocalFile(QFINDTESTDATA(sourceFile)));
+    else
+        browser->setSource(QUrl::fromLocalFile(QFINDTESTDATA(sourceFile)), sourceType);
+    QCOMPARE(browser->sourceType(), expectedSourceType);
     QTextFrame::iterator iterator = browser->document()->rootFrame()->begin();
     int maxHeadingLevel = -1;
     while (!iterator.atEnd())
         maxHeadingLevel = qMax(iterator++.currentBlock().blockFormat().intProperty(QTextFormat::HeadingLevel), maxHeadingLevel);
-#if QT_CONFIG(textmarkdownreader)
-    QCOMPARE(maxHeadingLevel, 3);
-#else
-    // If Qt doesn't support markdown, this document will be misidentified as HTML, so it won't have any H3's.
-    QCOMPARE(maxHeadingLevel, 0);
-#endif
+    QCOMPARE(maxHeadingLevel, expectedMaxHeadingLevel);
 }
 
 QTEST_MAIN(tst_QTextBrowser)