DiffEditor: Make it possible to paste snippets.

Add property "plainText" to DiffEditorDocument which
is queried as last resort by the code paster.

Task-number: QTCREATORBUG-12546
Task-number: QTCREATORBUG-9669
Change-Id: Iea9cd0d296bcc8e8a7300072c1a4a9068c2ab102
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/cpaster/cpasterplugin.cpp

@@ -215,8 +215,13 @@ void CodepasterPlugin::postEditor()
     if (const BaseTextEditor *textEditor = qobject_cast<const BaseTextEditor *>(editor))
         data = textEditor->selectedText();
     if (data.isEmpty()) {
-        if (auto textDocument = qobject_cast<const TextDocument *>(document))
+        if (auto textDocument = qobject_cast<const TextDocument *>(document)) {
             data = textDocument->plainText();
+        } else {
+            const QVariant textV = document->property("plainText"); // Diff Editor.
+            if (textV.type() == QVariant::String)
+                data = textV.toString();
+        }
     }
     post(data, mimeType);
 }

src/plugins/diffeditor/diffeditordocument.cpp

@@ -155,4 +155,9 @@ QString DiffEditorDocument::suggestedFileName() const
     return result + QStringLiteral(".patch");
 }
 
+QString DiffEditorDocument::plainText() const
+{
+    return m_controller->contents();
+}
+
 } // namespace DiffEditor

src/plugins/diffeditor/diffeditordocument.h

@@ -42,6 +42,7 @@ class DiffEditorController;
 class DIFFEDITOR_EXPORT DiffEditorDocument : public Core::BaseTextDocument
 {
     Q_OBJECT
+    Q_PROPERTY(QString plainText READ plainText STORED false) // For access by code pasters
 public:
     explicit DiffEditorDocument();
     virtual ~DiffEditorDocument();
@@ -58,6 +59,8 @@ public:
     bool reload(QString *errorString, ReloadFlag flag, ChangeType type);
     bool open(QString *errorString, const QString &fileName);
 
+    QString plainText() const;
+
 private:
     DiffEditorController *m_controller;
 };