qt: Disable requests context menu actions when appropriate

The recent requests table will allow you to copy data points even if they do not exist.
This PR implements checks to disable the 'copy label', 'copy message', and 'copy amount' context menu action if the respective fields are empty.

Author: jarolrod

src/qt/receivecoinsdialog.cpp

@@ -43,9 +43,9 @@ ReceiveCoinsDialog::ReceiveCoinsDialog(const PlatformStyle *_platformStyle, QWid
 
     // context menu actions
     QAction *copyURIAction = new QAction(tr("Copy URI"), this);
-    QAction *copyLabelAction = new QAction(tr("Copy label"), this);
-    QAction *copyMessageAction = new QAction(tr("Copy message"), this);
-    QAction *copyAmountAction = new QAction(tr("Copy amount"), this);
+    copyLabelAction = new QAction(tr("Copy label"), this);
+    copyMessageAction = new QAction(tr("Copy message"), this);
+    copyAmountAction = new QAction(tr("Copy amount"), this);
 
     // context menu
     contextMenu = new QMenu(this);
@@ -267,9 +267,18 @@ void ReceiveCoinsDialog::copyColumnToClipboard(int column)
 // context menu
 void ReceiveCoinsDialog::showMenu(const QPoint &point)
 {
-    if (!selectedRow().isValid()) {
+    const QModelIndex sel = selectedRow();
+    if (!sel.isValid()) {
         return;
     }
+
+    // disable context menu actions when appropriate
+    const RecentRequestsTableModel * const submodel = model->getRecentRequestsTableModel();
+    const RecentRequestEntry * const req = &submodel->entry(sel.row());
+    copyLabelAction->setDisabled(req->recipient.label.isEmpty());
+    copyMessageAction->setDisabled(req->recipient.message.isEmpty());
+    copyAmountAction->setDisabled(req->recipient.amount == 0);
+
     contextMenu->exec(QCursor::pos());
 }
 

src/qt/receivecoinsdialog.h

@@ -54,6 +54,9 @@ public Q_SLOTS:
     GUIUtil::TableViewLastColumnResizingFixer *columnResizingFixer;
     WalletModel *model;
     QMenu *contextMenu;
+    QAction *copyLabelAction;
+    QAction *copyMessageAction;
+    QAction *copyAmountAction;
     const PlatformStyle *platformStyle;
 
     QModelIndex selectedRow();