Improve UI of the search edit.

- The copy action (Control+C) when no text is selected copies the
  password of the current entry.  This should be reasonable when
  Control+B copies the username.

- Down at EOL moves the focus to the entry view.  Enter and Tab should
  do that, but it would be handy for user to be able to get to the third
  entry by hitting Down three times.

src/gui/DatabaseWidget.cpp

@@ -23,6 +23,7 @@
 #include <QHBoxLayout>
 #include <QLabel>
 #include <QLineEdit>
+#include <QKeyEvent>
 #include <QSplitter>
 #include <QTimer>
 #include <QProcess>
@@ -88,6 +89,7 @@ DatabaseWidget::DatabaseWidget(Database* db, QWidget* parent)
     m_searchUi->closeSearchButton->setShortcut(Qt::Key_Escape);
     m_searchWidget->hide();
     m_searchUi->caseSensitiveCheckBox->setVisible(false);
+    m_searchUi->searchEdit->installEventFilter(this);
 
     QVBoxLayout* vLayout = new QVBoxLayout(rightHandSideWidget);
     vLayout->setMargin(0);
@@ -982,3 +984,33 @@ bool DatabaseWidget::currentEntryHasNotes()
     }
     return !currentEntry->notes().isEmpty();
 }
+
+bool DatabaseWidget::eventFilter(QObject* object, QEvent* event)
+{
+    if (object == m_searchUi->searchEdit) {
+        if (event->type() == QEvent::KeyPress) {
+            QKeyEvent* keyEvent = static_cast<QKeyEvent*>(event);
+            if (keyEvent->matches(QKeySequence::Copy)) {
+                // If Control+C is pressed in the search edit when no
+                // text is selected, copy the password of the current
+                // entry.
+                Entry* currentEntry = m_entryView->currentEntry();
+                if (currentEntry && !m_searchUi->searchEdit->hasSelectedText()) {
+                    setClipboardTextAndMinimize(currentEntry->password());
+                    return true;
+                }
+            }
+            else if (keyEvent->matches(QKeySequence::MoveToNextLine)) {
+                // If Down is pressed at EOL in the search edit, move
+                // the focus to the entry view.
+                if (!m_searchUi->searchEdit->hasSelectedText() &&
+                    m_searchUi->searchEdit->cursorPosition() == m_searchUi->searchEdit->text().length()) {
+                    m_entryView->setFocus();
+                    return true;
+                }
+            }
+        }
+    }
+
+    return false;
+}

src/gui/DatabaseWidget.h

@@ -102,6 +102,9 @@ Q_SIGNALS:
     void splitterSizesChanged();
     void entryColumnSizesChanged();
 
+protected:
+    bool eventFilter(QObject* object, QEvent* event);
+
 public Q_SLOTS:
     void createEntry();
     void cloneEntry();