Help: Move viewer backend management from plugin to local help manager

which poses as a settings class.

Change-Id: Icb01f0d4750c2d197875954a648ae7358c4c217a
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/help/helpplugin.cpp

@@ -42,19 +42,8 @@
 #include "remotehelpfilter.h"
 #include "searchwidget.h"
 #include "searchtaskhandler.h"
-#include "textbrowserhelpviewer.h"
 #include "topicchooser.h"
 
-#ifdef QTC_LITEHTML_HELPVIEWER
-#include "litehtmlhelpviewer.h"
-#endif
-#ifdef QTC_MAC_NATIVE_HELPVIEWER
-#include "macwebkithelpviewer.h"
-#endif
-#ifdef QTC_WEBENGINE_HELPVIEWER
-#include "webenginehelpviewer.h"
-#endif
-
 #include <bookmarkmanager.h>
 #include <contentwindow.h>
 #include <indexwindow.h>
@@ -452,47 +441,9 @@ HelpViewer *HelpPluginPrivate::externalHelpViewer()
 
 HelpViewer *HelpPlugin::createHelpViewer(qreal zoom)
 {
-    // check for backends
-    using ViewerFactory = std::function<HelpViewer *()>;
-    using ViewerFactoryItem = QPair<QByteArray, ViewerFactory>; // id -> factory
-    QVector<ViewerFactoryItem> factories;
-#ifdef QTC_LITEHTML_HELPVIEWER
-    factories.append(qMakePair(QByteArray("litehtml"), [] { return new LiteHtmlHelpViewer(); }));
-#endif
-#ifdef QTC_WEBENGINE_HELPVIEWER
-    factories.append(
-        qMakePair(QByteArray("qtwebengine"), []() { return new WebEngineHelpViewer(); }));
-#endif
-    factories.append(
-        qMakePair(QByteArray("textbrowser"), []() { return new TextBrowserHelpViewer(); }));
-
-#ifdef QTC_MAC_NATIVE_HELPVIEWER
-    // default setting
-#ifdef QTC_MAC_NATIVE_HELPVIEWER_DEFAULT
-     factories.prepend(qMakePair(QByteArray("native"), []() { return new MacWebKitHelpViewer(); }));
-#else
-     factories.append(qMakePair(QByteArray("native"), []() { return new MacWebKitHelpViewer(); }));
-#endif
-#endif
-
-    HelpViewer *viewer = nullptr;
-
-    // check requested backend
-    const QByteArray backend = qgetenv("QTC_HELPVIEWER_BACKEND");
-    if (!backend.isEmpty()) {
-        const int pos = Utils::indexOf(factories, [backend](const ViewerFactoryItem &item) {
-            return backend == item.first;
-        });
-        if (pos == -1) {
-            qWarning("Help viewer backend \"%s\" not found, using default.", backend.constData());
-        } else {
-            viewer  = factories.at(pos).second();
-        }
-    }
-
-    if (!viewer)
-        viewer = factories.first().second();
-    QTC_ASSERT(viewer, return nullptr);
+    const HelpViewerFactory factory = LocalHelpManager::viewerBackend();
+    QTC_ASSERT(factory.create, return nullptr);
+    HelpViewer *viewer = factory.create();
 
     // initialize font
     viewer->setViewerFont(LocalHelpManager::fallbackFont());

src/plugins/help/localhelpmanager.cpp

@@ -29,6 +29,17 @@
 #include "helpconstants.h"
 #include "helpmanager.h"
 #include "helpviewer.h"
+#include "textbrowserhelpviewer.h"
+
+#ifdef QTC_WEBENGINE_HELPVIEWER
+#include "webenginehelpviewer.h"
+#endif
+#ifdef QTC_LITEHTML_HELPVIEWER
+#include "litehtmlhelpviewer.h"
+#endif
+#ifdef QTC_MAC_NATIVE_HELPVIEWER
+#include "macwebkithelpviewer.h"
+#endif
 
 #include <app/app_version.h>
 #include <coreplugin/icore.h>
@@ -276,6 +287,46 @@ void LocalHelpManager::setLastSelectedTab(int index)
     Core::ICore::settings()->setValue(kLastSelectedTabKey, index);
 }
 
+QByteArray LocalHelpManager::defaultViewerBackend()
+{
+    const QByteArray backend = qgetenv("QTC_HELPVIEWER_BACKEND");
+    if (Utils::contains(viewerBackends(), Utils::equal(&HelpViewerFactory::id, backend)))
+        return backend;
+    else if (!backend.isEmpty())
+        qWarning("Help viewer backend \"%s\" not found, using default.", backend.constData());
+#ifdef QTC_WEBENGINE_HELPVIEWER
+    return "qtwebengine";
+#else
+    return "textbrowser";
+#endif
+}
+
+QVector<HelpViewerFactory> LocalHelpManager::viewerBackends()
+{
+    QVector<HelpViewerFactory> result;
+#ifdef QTC_WEBENGINE_HELPVIEWER
+    result.append({"qtwebengine", tr("QtWebEngine"), []() { return new WebEngineHelpViewer; }});
+#endif
+#ifdef QTC_LITEHTML_HELPVIEWER
+    result.append({"litehtml", tr("litehtml"), []() { return new LiteHtmlHelpViewer; }});
+#endif
+#ifdef QTC_MAC_NATIVE_HELPVIEWER
+    result.append({"native", tr("WebKit"), []() { return new MacWebKitHelpViewer; }});
+#endif
+    result.append({"textbrowser", tr("QTextBrowser"), []() { return new TextBrowserHelpViewer; }});
+    return result;
+}
+
+HelpViewerFactory LocalHelpManager::viewerBackend()
+{
+    const QVector<HelpViewerFactory> factories = viewerBackends();
+    const auto backend = std::find_if(std::begin(factories),
+                                      std::end(factories),
+                                      Utils::equal(&HelpViewerFactory::id, defaultViewerBackend()));
+    QTC_ASSERT(backend != std::end(factories), return {});
+    return *backend;
+}
+
 void LocalHelpManager::setupGuiHelpEngine()
 {
     if (m_needsCollectionFile) {

src/plugins/help/localhelpmanager.h

@@ -26,6 +26,7 @@
 #pragma once
 
 #include <coreplugin/helpmanager.h>
+#include <utils/optional.h>
 
 #include <QMetaType>
 #include <QMutex>
@@ -33,6 +34,8 @@
 #include <QUrl>
 #include <QStandardItemModel>
 
+#include <functional>
+
 QT_FORWARD_DECLARE_CLASS(QHelpEngine)
 
 class BookmarkManager;
@@ -40,6 +43,15 @@ class BookmarkManager;
 namespace Help {
 namespace Internal {
 
+class HelpViewer;
+
+struct HelpViewerFactory
+{
+    QByteArray id;
+    QString displayName;
+    std::function<HelpViewer *()> create;
+};
+
 class LocalHelpManager : public QObject
 {
     Q_OBJECT
@@ -90,6 +102,10 @@ public:
     static int lastSelectedTab();
     static void setLastSelectedTab(int index);
 
+    static QByteArray defaultViewerBackend();
+    static QVector<HelpViewerFactory> viewerBackends();
+    static HelpViewerFactory viewerBackend();
+
     static void setupGuiHelpEngine();
     static void setEngineNeedsUpdate();