Introduce dragging for all explorer nodes.

Extend drop support with variant values. A drop may be a file drop or a
value drop or both.

Rename Utils::FileDropSupport to Utils::DropSupport and add methods to
add not only files but any QVariant value to the mime data. Project
explorer adds dragged nodes (which will be needed for future ModelEditor
plugin).

Change-Id: I799542c60fdecb3e64af0d3ba47b6caa9adbcfd7
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

1 files changed, 240 insertions, 0 deletions

diff --git a/src/libs/utils/dropsupport.cpp b/src/libs/utils/dropsupport.cpp
new file mode 100644
index 0000000000..6f325a175b
--- /dev/null
+++ b/src/libs/utils/dropsupport.cpp
@@ -0,0 +1,240 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company.  For licensing terms and
+** conditions see http://www.qt.io/terms-conditions.  For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** 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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "dropsupport.h"
+
+#include "qtcassert.h"
+
+#include <QUrl>
+#include <QWidget>
+#include <QDropEvent>
+#include <QTimer>
+
+#ifdef Q_OS_OSX
+// for file drops from Finder, working around QTBUG-40449
+namespace Utils {
+namespace Internal {
+extern QUrl filePathUrl(const QUrl &url);
+} // Internal
+} // Utils
+#endif
+
+namespace Utils {
+
+static bool isFileDrop(const QMimeData *d, QList<DropSupport::FileSpec> *files = 0)
+{
+    // internal drop
+    if (const DropMimeData *internalData = qobject_cast<const DropMimeData *>(d)) {
+        if (files)
+            *files = internalData->files();
+        return !internalData->files().isEmpty();
+    }
+
+    // external drop
+    if (files)
+        files->clear();
+    // Extract dropped files from Mime data.
+    if (!d->hasUrls())
+        return false;
+    const QList<QUrl> urls = d->urls();
+    if (urls.empty())
+        return false;
+    // Try to find local files
+    bool hasFiles = false;
+    const QList<QUrl>::const_iterator cend = urls.constEnd();
+    for (QList<QUrl>::const_iterator it = urls.constBegin(); it != cend; ++it) {
+        QUrl url = *it;
+#ifdef Q_OS_OSX
+        // for file drops from Finder, working around QTBUG-40449
+        url = Internal::filePathUrl(url);
+#endif
+        const QString fileName = url.toLocalFile();
+        if (!fileName.isEmpty()) {
+            hasFiles = true;
+            if (files)
+                files->append(DropSupport::FileSpec(fileName));
+            else
+                break; // No result list, sufficient for checking
+        }
+    }
+    return hasFiles;
+}
+
+DropSupport::DropSupport(QWidget *parentWidget, const DropFilterFunction &filterFunction)
+    : QObject(parentWidget),
+      m_filterFunction(filterFunction)
+{
+    QTC_ASSERT(parentWidget, return);
+    parentWidget->setAcceptDrops(true);
+    parentWidget->installEventFilter(this);
+}
+
+QStringList DropSupport::mimeTypesForFilePaths()
+{
+    return QStringList() << QStringLiteral("text/uri-list");
+}
+
+bool DropSupport::isFileDrop(QDropEvent *event) const
+{
+    return Utils::isFileDrop(event->mimeData());
+}
+
+bool DropSupport::isValueDrop(QDropEvent *event) const
+{
+    if (const DropMimeData *internalData = qobject_cast<const DropMimeData *>(event->mimeData())) {
+        return !internalData->values().isEmpty();
+    }
+    return false;
+}
+
+bool DropSupport::eventFilter(QObject *obj, QEvent *event)
+{
+    Q_UNUSED(obj)
+    if (event->type() == QEvent::DragEnter) {
+        auto dee = static_cast<QDragEnterEvent *>(event);
+        if ((isFileDrop(dee) || isValueDrop(dee)) && (!m_filterFunction || m_filterFunction(dee, this))) {
+            event->accept();
+        } else {
+            event->ignore();
+        }
+        return true;
+    } else if (event->type() == QEvent::DragMove) {
+        event->accept();
+        return true;
+    } else if (event->type() == QEvent::Drop) {
+        bool accepted = false;
+        auto de = static_cast<QDropEvent *>(event);
+        if (!m_filterFunction || m_filterFunction(de, this)) {
+            const DropMimeData *fileDropMimeData = qobject_cast<const DropMimeData *>(de->mimeData());
+            QList<FileSpec> tempFiles;
+            if (Utils::isFileDrop(de->mimeData(), &tempFiles)) {
+                event->accept();
+                accepted = true;
+                if (fileDropMimeData && fileDropMimeData->isOverridingFileDropAction())
+                    de->setDropAction(fileDropMimeData->overrideFileDropAction());
+                else
+                    de->acceptProposedAction();
+                bool needToScheduleEmit = m_files.isEmpty();
+                m_files.append(tempFiles);
+                if (needToScheduleEmit) { // otherwise we already have a timer pending
+                    // Delay the actual drop, to avoid conflict between
+                    // actions that happen when opening files, and actions that the item views do
+                    // after the drag operation.
+                    // If we do not do this, e.g. dragging from Outline view crashes if the editor and
+                    // the selected item changes
+                    QTimer::singleShot(100, this, SLOT(emitFilesDropped()));
+                }
+            }
+            if (fileDropMimeData && !fileDropMimeData->values().isEmpty()) {
+                event->accept();
+                accepted = true;
+                bool needToScheduleEmit = m_values.isEmpty();
+                m_values.append(fileDropMimeData->values());
+                m_dropPos = de->pos();
+                if (needToScheduleEmit)
+                    QTimer::singleShot(100, this, SLOT(emitValuesDropped()));
+            }
+        }
+        if (!accepted) {
+            event->ignore();
+        }
+        return true;
+    }
+    return false;
+}
+
+void DropSupport::emitFilesDropped()
+{
+    QTC_ASSERT(!m_files.isEmpty(), return);
+    emit filesDropped(m_files);
+    m_files.clear();
+}
+
+void DropSupport::emitValuesDropped()
+{
+    QTC_ASSERT(!m_values.isEmpty(), return);
+    emit valuesDropped(m_values, m_dropPos);
+    m_values.clear();
+}
+
+/*!
+    Sets the drop action to effectively use, instead of the "proposed" drop action from the
+    drop event. This can be useful when supporting move drags within an item view, but not
+    "moving" an item from the item view into a split.
+ */
+DropMimeData::DropMimeData()
+    : m_overrideDropAction(Qt::IgnoreAction),
+      m_isOverridingDropAction(false)
+{
+
+}
+
+void DropMimeData::setOverrideFileDropAction(Qt::DropAction action)
+{
+    m_isOverridingDropAction = true;
+    m_overrideDropAction = action;
+}
+
+Qt::DropAction DropMimeData::overrideFileDropAction() const
+{
+    return m_overrideDropAction;
+}
+
+bool DropMimeData::isOverridingFileDropAction() const
+{
+    return m_isOverridingDropAction;
+}
+
+void DropMimeData::addFile(const QString &filePath, int line, int column)
+{
+    // standard mime data
+    QList<QUrl> currentUrls = urls();
+    currentUrls.append(QUrl::fromLocalFile(filePath));
+    setUrls(currentUrls);
+    // special mime data
+    m_files.append(DropSupport::FileSpec(filePath, line, column));
+}
+
+QList<DropSupport::FileSpec> DropMimeData::files() const
+{
+    return m_files;
+}
+
+void DropMimeData::addValue(const QVariant &value)
+{
+    m_values.append(value);
+}
+
+QList<QVariant> DropMimeData::values() const
+{
+    return m_values;
+}
+
+} // namespace Utils