PoC: syntax highlighting

Signed-off-by: Carl Schwan <carl@carlschwan.eu>

CMakeLists.txt

@@ -82,7 +82,7 @@ set_package_properties(Qt${QT_MAJOR_VERSION} PROPERTIES
     TYPE REQUIRED
     PURPOSE "Basic application components"
 )
-find_package(KF${QT_MAJOR_VERSION} ${KF_MIN_VERSION} COMPONENTS Kirigami2 I18n Notifications Config CoreAddons Sonnet ItemModels)
+find_package(KF${QT_MAJOR_VERSION} ${KF_MIN_VERSION} COMPONENTS Kirigami2 I18n Notifications Config CoreAddons Sonnet ItemModels SyntaxHighlighting)
 set_package_properties(KF${QT_MAJOR_VERSION} PROPERTIES
     TYPE REQUIRED
     PURPOSE "Basic application components"

src/CMakeLists.txt

@@ -136,6 +136,7 @@ add_library(neochat STATIC
     mediasizehelper.h
     eventhandler.cpp
     enums/delegatetype.h
+    messageformatter.cpp
 )
 
 ecm_qt_declare_logging_category(neochat
@@ -199,7 +200,7 @@ else()
 endif()
 
 target_include_directories(neochat PRIVATE ${CMAKE_BINARY_DIR})
-target_link_libraries(neochat PUBLIC Qt::Core Qt::Quick Qt::Qml Qt::Gui Qt::Multimedia Qt::Network Qt::QuickControls2 KF${QT_MAJOR_VERSION}::I18n KF${QT_MAJOR_VERSION}::Kirigami2 KF${QT_MAJOR_VERSION}::Notifications KF${QT_MAJOR_VERSION}::ConfigCore KF${QT_MAJOR_VERSION}::ConfigGui KF${QT_MAJOR_VERSION}::CoreAddons KF${QT_MAJOR_VERSION}::SonnetCore  KF${QT_MAJOR_VERSION}::ItemModels Quotient${QUOTIENT_SUFFIX} cmark::cmark QCoro::Core)
+target_link_libraries(neochat PUBLIC Qt::Core Qt::Quick Qt::Qml Qt::Gui Qt::Multimedia Qt::Network Qt::QuickControls2 Qt::Xml KF${QT_MAJOR_VERSION}::I18n KF${QT_MAJOR_VERSION}::Kirigami2 KF${QT_MAJOR_VERSION}::Notifications KF${QT_MAJOR_VERSION}::ConfigCore KF${QT_MAJOR_VERSION}::ConfigGui KF${QT_MAJOR_VERSION}::CoreAddons KF${QT_MAJOR_VERSION}::SonnetCore  KF${QT_MAJOR_VERSION}::ItemModels KF${QT_MAJOR_VERSION}::SyntaxHighlighting Quotient${QUOTIENT_SUFFIX} cmark::cmark QCoro::Core)
 
 kconfig_add_kcfg_files(neochat GENERATE_MOC neochatconfig.kcfgc)
 

src/main.cpp

@@ -107,6 +107,8 @@
 #include <Windows.h>
 #endif
 
+#include "messageformatter.h"
+
 using namespace Quotient;
 
 class NetworkAccessManagerFactory : public QQmlNetworkAccessManagerFactory
@@ -228,6 +230,12 @@ int main(int argc, char *argv[])
     Login *login = new Login();
     UrlHelper urlHelper;
 
+    MessageFormatter formatter;
+    // formatter.formatInternal("<p>hrrejoire</p>\n<pre><code class=\"language-js\">var i = 0; i++; function\n</code></pre>\n<p>rekore</p>\n", new
+    // QTextDocument);
+
+    // return 0;
+
 #ifdef HAVE_COLORSCHEME
     ColorSchemer colorScheme;
     qmlRegisterSingletonInstance<ColorSchemer>("org.kde.neochat", 1, 0, "ColorSchemer", &colorScheme);
@@ -236,6 +244,7 @@ int main(int argc, char *argv[])
     }
 #endif
 
+    qmlRegisterSingletonInstance<MessageFormatter>("org.kde.neochat", 1, 0, "MessageFormatter", &formatter);
     qmlRegisterSingletonInstance("org.kde.neochat", 1, 0, "Controller", &Controller::instance());
     qmlRegisterSingletonInstance("org.kde.neochat", 1, 0, "NotificationsManager", &NotificationsManager::instance());
     qmlRegisterSingletonInstance("org.kde.neochat", 1, 0, "Clipboard", &clipboard);

src/messageformatter.cpp

@@ -0,0 +1,133 @@
+// SPDX-FileCopyrightText: 2021 Carson Black <uhhadd@gmail.com>
+// SPDX-FileCopyrightText: 2022 Carl Schwan <carl@carlschwan.eu>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "messageformatter.h"
+
+#include <QDomDocument>
+#include <QGuiApplication>
+#include <QPalette>
+#include <QQmlContext>
+#include <QQmlProperty>
+#include <QTextCursor>
+#include <QTextDocumentFragment>
+
+#include <KSyntaxHighlighting/definition.h>
+#include <KSyntaxHighlighting/repository.h>
+#include <KSyntaxHighlighting/syntaxhighlighter.h>
+#include <KSyntaxHighlighting/theme.h>
+
+QTextDocumentFragment copyTextLayoutFrom(QTextDocument *document)
+{
+    QTextCursor sourceCursor(document);
+    sourceCursor.select(QTextCursor::Document);
+
+    QTextDocument helper;
+
+    // copy the content fragment from the source document into our helper document
+    QTextCursor curs(&helper);
+    curs.insertFragment(sourceCursor.selection());
+    curs.select(QTextCursor::Document);
+
+    // not sure why, but fonts get lost. since this is for codeblocks, we can
+    // just force the mono font. anyone copying this code would probably want
+    // to fix the problem proper if it's not also for codeblocks.
+    const auto fixedFont = QFontDatabase::systemFont(QFontDatabase::FixedFont);
+
+    const int docStart = sourceCursor.selectionStart();
+    const int docEnd = helper.characterCount() - 1;
+
+    // since the copied fragment above lost the qsyntaxhighlighter stuff,
+    // we gotta go through the qtextlayout and apply those styles to the
+    // document
+    const auto end = document->findBlock(sourceCursor.selectionEnd()).next();
+    for (auto current = document->findBlock(docStart); current.isValid() && current != end; current = current.next()) {
+        const auto layout = current.layout();
+
+        // iterate through the formats, applying them to our document
+        for (const auto &span : layout->formats()) {
+            const int start = current.position() + span.start - docStart;
+            const int end = start + span.length;
+
+            curs.setPosition(qMax(start, 0));
+            curs.setPosition(qMin(end, docEnd), QTextCursor::KeepAnchor);
+
+            auto fmt = span.format;
+            fmt.setFont(fixedFont);
+
+            curs.setCharFormat(fmt);
+        }
+    }
+
+    return QTextDocumentFragment(&helper);
+}
+
+QTextDocumentFragment highlight(const QString &code, const QString &language)
+{
+    using namespace KSyntaxHighlighting;
+
+    static Repository repo;
+
+    auto theme = repo.themeForPalette(QGuiApplication::palette());
+    auto definition = repo.definitionForFileName(QLatin1String("file.") + language);
+
+    QTextDocument doku(code);
+
+    QScopedPointer<SyntaxHighlighter> highlighter(new SyntaxHighlighter(&doku));
+    highlighter->setTheme(theme);
+    highlighter->setDefinition(definition);
+
+    return copyTextLayoutFrom(&doku);
+}
+
+bool extractCodeBlock(QTextCursor cursor, QDomElement element)
+{
+    const auto codeNode = element.firstChild();
+    if (!codeNode.isNull()) {
+        const auto code = codeNode.toElement();
+        if (!code.isNull() && code.tagName() == QLatin1String("code")) {
+            QString lang;
+            auto langClass = code.attribute(QLatin1String("class"), QLatin1String("none"));
+            if (langClass != QLatin1String("none") && langClass.startsWith(QLatin1String("language-"))) {
+                lang = langClass.remove(0, 9);
+            }
+
+            if (!lang.isNull()) {
+                cursor.insertFragment(highlight(code.text(), lang));
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+QString MessageFormatter::formatInternal(const QString &messageBody, QTextDocument *document)
+{
+    QTextCursor curs(document);
+    QDomDocument doc(QLatin1String("htmlement"));
+    doc.setContent(QStringLiteral("<div>%1</div>").arg(messageBody));
+    QDomElement docElem = doc.documentElement();
+    QDomNode n = docElem.firstChild();
+    while (!n.isNull()) {
+        QDomElement e = n.toElement();
+        if (!e.isNull()) {
+            if (e.tagName() != QLatin1String("pre") || !extractCodeBlock(curs, e)) {
+                QString outText;
+                QTextStream out(&outText);
+                e.save(out, 0);
+                curs.insertHtml(outText);
+            }
+        }
+        n = n.nextSibling();
+    }
+
+    Q_EMIT document->contentsChanged();
+    return document->toHtml();
+}
+
+QString MessageFormatter::format(const QString &messageBody, QQuickTextDocument *doc, QQuickItem *item)
+{
+    QColor linkColor = QQmlProperty(item, QLatin1String("Kirigami.Theme.linkColor"), qmlContext(item)).read().value<QColor>();
+
+    return formatInternal(messageBody, doc->textDocument());
+}

src/messageformatter.h

@@ -0,0 +1,13 @@
+// SPDX-FileCopyrightText: 2022 Carl Schwan <carl@carlschwan.eu>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include <QQuickItem>
+#include <QQuickTextDocument>
+
+class MessageFormatter : public QObject
+{
+    Q_OBJECT
+public:
+    Q_INVOKABLE QString format(const QString &messageBody, QQuickTextDocument *doc, QQuickItem *item);
+    Q_INVOKABLE QString formatInternal(const QString &messageBody, QTextDocument *doc);
+};

src/qml/Component/Timeline/RichLabel.qml

@@ -44,6 +44,7 @@ TextEdit {
     property bool spoilerRevealed: !hasSpoiler.test(textMessage)
 
     ListView.onReused: Qt.binding(() => !hasSpoiler.test(textMessage))
+    onTextMessageChanged: text = MessageFormatter.format(textMessage, contentLabel.textDocument, contentLabel)
 
     persistentSelection: true
 
@@ -52,6 +53,7 @@ TextEdit {
         Controller.forceRefreshTextDocument(root.textDocument, root)
     }
 
+    /*
     text: "<style>
 table {
     width:100%;
@@ -84,7 +86,11 @@ a{
     background: " + Kirigami.Theme.textColor + ";
 }
 " : "") + "
+<<<<<<< HEAD:src/qml/Component/Timeline/RichLabel.qml
 </style>" + textMessage
+=======
+</style>" + (isEmote ? "* <a href='https://matrix.to/#/" + author.id + "' style='color: " + author.color + "'>" + author.displayName + "</a> " : "") + textMessage + (isEdited ? (" <span style=\"color: " + Kirigami.Theme.disabledTextColor + "\">" + "<span style='font-size: " + Kirigami.Theme.defaultFont.pixelSize +"px'>" + i18n(" (edited)") + "</span>") : "")
+    */
 
     color: Kirigami.Theme.textColor
     selectedTextColor: Kirigami.Theme.highlightedTextColor