Editors: Support dragging from outline views

Fill the line and column information in the location returned by
QmlOutlineModel::sourceLocation for that.
The drag & drop code also needed a way to override the executed drop
action for file drops, because the QML outline supports move-drags, which
would lead to the items being removed from the outline when dragged onto
a split...

Change-Id: I2478abc7d5aa2f3aa676cdd609ecb69a50adce8c
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>

4 files changed, 87 insertions, 3 deletions

diff --git a/src/libs/cplusplus/OverviewModel.cpp b/src/libs/cplusplus/OverviewModel.cpp
index 372d80fe5a..e016109017 100644
--- a/src/libs/cplusplus/OverviewModel.cpp
+++ b/src/libs/cplusplus/OverviewModel.cpp
@@ -34,6 +34,7 @@
 #include <cplusplus/Scope.h>
 #include <cplusplus/Literals.h>
 #include <cplusplus/Symbols.h>
+#include <utils/fileutils.h>
 
 using namespace CPlusPlus;
 
@@ -242,3 +243,35 @@ void OverviewModel::rebuild(Document::Ptr doc)
     _cppDocument = doc;
     endResetModel();
 }
+
+Qt::ItemFlags OverviewModel::flags(const QModelIndex &index) const
+{
+    Q_UNUSED(index)
+    return Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsDragEnabled;
+}
+
+Qt::DropActions OverviewModel::supportedDragActions() const
+{
+    return Qt::MoveAction;
+}
+
+QStringList OverviewModel::mimeTypes() const
+{
+    return Utils::FileDropSupport::mimeTypesForFilePaths();
+}
+
+QMimeData *OverviewModel::mimeData(const QModelIndexList &indexes) const
+{
+    auto mimeData = new Utils::FileDropMimeData;
+    foreach (const QModelIndex &index, indexes) {
+        const QVariant fileName = data(index, FileNameRole);
+        if (!fileName.canConvert<QString>())
+            continue;
+        const QVariant lineNumber = data(index, LineNumberRole);
+        if (!fileName.canConvert<unsigned>())
+            continue;
+        mimeData->addFile(fileName.toString(), lineNumber.value<unsigned>());
+    }
+    return mimeData;
+}
+
diff --git a/src/libs/cplusplus/OverviewModel.h b/src/libs/cplusplus/OverviewModel.h
index 3f739c2a66..683da81c62 100644
--- a/src/libs/cplusplus/OverviewModel.h
+++ b/src/libs/cplusplus/OverviewModel.h
@@ -61,6 +61,11 @@ public:
     Document::Ptr document() const;
     Symbol *symbolFromIndex(const QModelIndex &index) const;
 
+    Qt::ItemFlags flags(const QModelIndex &index) const;
+    Qt::DropActions supportedDragActions() const;
+    QStringList mimeTypes() const;
+    QMimeData *mimeData(const QModelIndexList &indexes) const;
+
 public Q_SLOTS:
     void rebuild(CPlusPlus::Document::Ptr doc);
 
diff --git a/src/libs/utils/fileutils.cpp b/src/libs/utils/fileutils.cpp
index a314c69ff5..1a07192066 100644
--- a/src/libs/utils/fileutils.cpp
+++ b/src/libs/utils/fileutils.cpp
@@ -778,12 +778,22 @@ bool FileDropSupport::eventFilter(QObject *obj, QEvent *event)
         QList<FileSpec> tempFiles;
         if (isFileDrop(de->mimeData(), &tempFiles)
                 && (!m_filterFunction || m_filterFunction(de))) {
+            const FileDropMimeData *fileDropMimeData = qobject_cast<const FileDropMimeData *>(de->mimeData());
             event->accept();
-            de->acceptProposedAction();
+            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
-                QTimer::singleShot(0, this, SLOT(emitFilesDropped()));
+            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()));
+            }
         } else {
             event->ignore();
         }
@@ -799,6 +809,34 @@ void FileDropSupport::emitFilesDropped()
     m_files.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.
+ */
+FileDropMimeData::FileDropMimeData()
+    : m_overrideDropAction(Qt::IgnoreAction),
+      m_isOverridingDropAction(false)
+{
+
+}
+
+void FileDropMimeData::setOverrideFileDropAction(Qt::DropAction action)
+{
+    m_isOverridingDropAction = true;
+    m_overrideDropAction = action;
+}
+
+Qt::DropAction FileDropMimeData::overrideFileDropAction() const
+{
+    return m_overrideDropAction;
+}
+
+bool FileDropMimeData::isOverridingFileDropAction() const
+{
+    return m_isOverridingDropAction;
+}
+
 void FileDropMimeData::addFile(const QString &filePath, int line, int column)
 {
     // standard mime data
diff --git a/src/libs/utils/fileutils.h b/src/libs/utils/fileutils.h
index 1f20d645ff..df874c0d92 100644
--- a/src/libs/utils/fileutils.h
+++ b/src/libs/utils/fileutils.h
@@ -236,11 +236,19 @@ class QTCREATOR_UTILS_EXPORT FileDropMimeData : public QMimeData
 {
     Q_OBJECT
 public:
+    FileDropMimeData();
+
+    void setOverrideFileDropAction(Qt::DropAction action);
+    Qt::DropAction overrideFileDropAction() const;
+    bool isOverridingFileDropAction() const;
+
     void addFile(const QString &filePath, int line = -1, int column = -1);
     QList<FileDropSupport::FileSpec> files() const;
 
 private:
     QList<FileDropSupport::FileSpec> m_files;
+    Qt::DropAction m_overrideDropAction;
+    bool m_isOverridingDropAction;
 };
 
 } // namespace Utils