Implement a common interface for help viewers.

Both implementations are now split into two source files, based on the
base class type. They share also a commen implementation, but the class
interface looks now clean to the outside. Adopt other classes for use.

src/plugins/help/helpviewer.cpp

@@ -0,0 +1,129 @@
+/**************************************************************************
+**
+** This file is part of Qt Creator
+**
+** Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+**
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** Commercial Usage
+**
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Commercial License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Nokia.
+**
+** GNU Lesser General Public License Usage
+**
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at http://qt.nokia.com/contact.
+**
+**************************************************************************/
+
+#include "helpviewer.h"
+#include "helpconstants.h"
+#include "helpmanager.h"
+
+#include <QtCore/QCoreApplication>
+#include <QtCore/QFileInfo>
+#include <QtCore/QStringBuilder>
+#include <QtCore/QTemporaryFile>
+#include <QtCore/QUrl>
+
+#include <QtGui/QDesktopServices>
+#include <QtGui/QMouseEvent>
+
+#include <QtHelp/QHelpEngineCore>
+
+using namespace Help::Internal;
+
+QString HelpViewer::AboutBlankPage =
+    QCoreApplication::translate("HelpViewer", "<title>about:blank</title>");
+
+QString HelpViewer::PageNotFoundMessage =
+    QCoreApplication::translate("HelpViewer", "<title>Error 404...</title><div "
+    "align=\"center\"><br><br><h1>The page could not be found</h1><br><h3>'%1'"
+    "</h3></div>");
+
+bool HelpViewer::isLocalUrl(const QUrl &url)
+{
+    const QString &scheme = url.scheme();
+    return scheme.isEmpty()
+        || scheme == QLatin1String("file")
+        || scheme == QLatin1String("qrc")
+        || scheme == QLatin1String("data")
+        || scheme == QLatin1String("qthelp")
+        || scheme == QLatin1String("about");
+}
+
+bool HelpViewer::canOpenPage(const QString &url)
+{
+    return url.endsWith(QLatin1String(".html"), Qt::CaseInsensitive)
+        || url.endsWith(QLatin1String(".htm"), Qt::CaseInsensitive)
+        || url == Help::Constants::AboutBlank;
+}
+
+bool HelpViewer::launchWithExternalApp(const QUrl &url)
+{
+    if (isLocalUrl(url)) {
+        const QHelpEngineCore &helpEngine = Help::HelpManager::helpEngineCore();
+        const QUrl &resolvedUrl = helpEngine.findFile(url);
+        if (!resolvedUrl.isValid())
+            return false;
+
+        const QString& path = resolvedUrl.path();
+        if (!canOpenPage(path)) {
+            QTemporaryFile tmpTmpFile;
+            if (!tmpTmpFile.open())
+                return false;
+
+            const QString &extension = QFileInfo(path).completeSuffix();
+            QFile actualTmpFile(tmpTmpFile.fileName() % QLatin1String(".")
+                % extension);
+            if (!actualTmpFile.open(QIODevice::ReadWrite | QIODevice::Truncate))
+                return false;
+
+            actualTmpFile.write(helpEngine.fileData(resolvedUrl));
+            actualTmpFile.close();
+            return QDesktopServices::openUrl(QUrl(actualTmpFile.fileName()));
+        }
+    } else if (url.scheme() == QLatin1String("http")) {
+        return QDesktopServices::openUrl(url);
+    }
+    return false;
+}
+
+void HelpViewer::home()
+{
+    const QHelpEngineCore &engine = Help::HelpManager::helpEngineCore();
+    QString homepage = engine.customValue(QLatin1String("HomePage"),
+        QLatin1String("")).toString();
+
+    if (homepage.isEmpty()) {
+        homepage = engine.customValue(QLatin1String("DefaultHomePage"),
+            Help::Constants::AboutBlank).toString();
+    }
+
+    setSource(homepage);
+}
+
+bool HelpViewer::handleForwardBackwardMouseButtons(QMouseEvent *event)
+{
+    if (event->button() == Qt::XButton1) {
+        backward();
+        return true;
+    }
+    if (event->button() == Qt::XButton2) {
+        forward();
+        return true;
+    }
+
+    return false;
+}