Qt: Signal empty display filter bar

If a display filter is applied, but the display filter bar
has been cleared by deleting the context (either by setting a
space or backspacing over the filter), it is not clearly indicated
that the filter is still being applied.

Bug: 12438
Change-Id: Ibd4c48b094467182ed51e9859e0d5fad770000c7
Reviewed-on: https://code.wireshark.org/review/35070
Petri-Dish: Roland Knall <rknall@gmail.com>
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Roland Knall <rknall@gmail.com>

2 files changed, 15 insertions, 4 deletions

diff --git a/ui/qt/widgets/display_filter_edit.cpp b/ui/qt/widgets/display_filter_edit.cpp
index 1a4458c904..29d036a397 100644
--- a/ui/qt/widgets/display_filter_edit.cpp
+++ b/ui/qt/widgets/display_filter_edit.cpp
@@ -69,7 +69,8 @@ DisplayFilterEdit::DisplayFilterEdit(QWidget *parent, DisplayFilterEditType type
     bookmark_button_(NULL),
     clear_button_(NULL),
     apply_button_(NULL),
-    leftAlignActions_(false)
+    leftAlignActions_(false),
+    last_applied_(QString())
 {
     setAccessibleName(tr("Display filter entry"));
 
@@ -333,8 +334,10 @@ void DisplayFilterEdit::checkFilter(const QString& filter_text)
 
         if ( filter_text.length() > 0 )
             clear_button_->setVisible(true);
-        else
-            setPlaceholderText("");
+        else if ( last_applied_.length() > 0 )
+            setPlaceholderText(tr("Current filter: %1").arg(last_applied_));
+        else if ( filter_text.length() <= 0 && last_applied_.length() <= 0 )
+            clear_button_->setVisible(false);
 
         alignActionButtons();
     }
@@ -548,6 +551,7 @@ void DisplayFilterEdit::clearFilter()
 {
     clear();
 
+    last_applied_ = QString();
     updateClearButton();
 
     emit filterPackets(QString(), true);
@@ -558,6 +562,9 @@ void DisplayFilterEdit::applyDisplayFilter()
     if (syntaxState() == Invalid)
         return;
 
+    if ( text().length() > 0 )
+        last_applied_ = text();
+
     updateClearButton();
 
     emit filterPackets(text(), true);
@@ -642,7 +649,9 @@ void DisplayFilterEdit::applyOrPrepareFilter()
     if ( ! pa || pa->property("display_filter").toString().isEmpty() )
         return;
 
-    setText(pa->property("display_filter").toString());
+    QString filterText = pa->property("display_filter").toString();
+    last_applied_ = filterText;
+    setText(filterText);
 
     // Holding down the Shift key will only prepare filter.
     if (!(QApplication::keyboardModifiers() & Qt::ShiftModifier)) {
@@ -730,6 +739,7 @@ void DisplayFilterEdit::dropEvent(QDropEvent *event)
                 return;
             }
 
+            last_applied_ = filterText;
             setText(filterText);
 
             // Holding down the Shift key will only prepare filter.
diff --git a/ui/qt/widgets/display_filter_edit.h b/ui/qt/widgets/display_filter_edit.h
index a87adca67f..d3b181dff7 100644
--- a/ui/qt/widgets/display_filter_edit.h
+++ b/ui/qt/widgets/display_filter_edit.h
@@ -75,6 +75,7 @@ private:
     StockIconToolButton *clear_button_;
     StockIconToolButton *apply_button_;
     bool leftAlignActions_;
+    QString last_applied_;
 
     void setDefaultPlaceholderText();
     void buildCompletionList(const QString& field_word);