Smart Playlists: Add empty/not empty operators

src/smartplaylists/searchterm.cpp

@@ -128,6 +128,10 @@ QString SearchTerm::ToSql() const {
       } else {
         return col + " <> " + value;
       }
+    case Op_Empty:
+      return col + " = ''";
+    case Op_NotEmpty:
+      return col + " <> ''";
   }
 
   return QString();
@@ -143,6 +147,11 @@ bool SearchTerm::is_valid() const {
 
   switch (TypeOf(field_)) {
     case Type_Text:
+      if (operator_ == SearchTerm::Op_Empty || operator_ == SearchTerm::Op_NotEmpty) {
+        return true;
+      }
+      // Empty fields should be possible.
+      // All values for Type_Text should be valid.
       return !value_.toString().isEmpty();
     case Type_Date:
       return value_.toInt() != 0;
@@ -199,7 +208,8 @@ OperatorList SearchTerm::OperatorsForType(Type type) {
   switch (type) {
     case Type_Text:
       return OperatorList() << Op_Contains << Op_NotContains << Op_Equals
-                            << Op_NotEquals << Op_StartsWith << Op_EndsWith;
+                            << Op_NotEquals << Op_Empty << Op_NotEmpty
+                            << Op_StartsWith << Op_EndsWith;
     case Type_Date:
       return OperatorList() << Op_Equals << Op_NotEquals << Op_GreaterThan
                             << Op_LessThan << Op_NumericDate
@@ -249,6 +259,10 @@ QString SearchTerm::OperatorText(Type type, Operator op) {
       return QObject::tr("equals");
     case Op_NotEquals:
       return QObject::tr("not equals");
+    case Op_Empty:
+      return QObject::tr("empty");
+    case Op_NotEmpty:
+      return QObject::tr("not empty");
     default:
       return QString();
   }

src/smartplaylists/searchterm.h

@@ -80,7 +80,10 @@ class SearchTerm {
     // For numeric dates (e.g. not in the last X days)
     Op_NumericDateNot = 10,
 
-    // Next value = 11
+    Op_Empty = 11,
+    Op_NotEmpty = 12,
+
+    // Next value = 13
   };
 
   enum Type {

src/smartplaylists/searchtermwidget.cpp

@@ -163,7 +163,11 @@ void SearchTermWidget::FieldChanged(int index) {
       page = ui_->page_rating;
       break;
     case SearchTerm::Type_Text:
-      page = ui_->page_text;
+      if (ui_->op->currentIndex() == 4 || ui_->op->currentIndex() == 5) {
+        page = ui_->page_empty;
+      } else {
+        page = ui_->page_text;
+      }
       break;
     case SearchTerm::Type_Invalid:
       page = nullptr;
@@ -189,8 +193,21 @@ void SearchTermWidget::FieldChanged(int index) {
 }
 
 void SearchTermWidget::OpChanged(int index) {
+  if ((ui_->value_stack->currentWidget() == ui_->page_text) ||
+      (ui_->value_stack->currentWidget() == ui_->page_empty)) {
+    QWidget* page = nullptr;
+    // This assumes the operators always appear in the same order.
+    // Needs a better way for checking which is the current operator.
+    if (index == 4 || index == 5) {
+      page = ui_->page_empty;
+    } else {
+      page = ui_->page_text;
+    }
+    ui_->value_stack->setCurrentWidget(page);
+  }
+
   // We need to change the page only in the following case
-  if ((ui_->value_stack->currentWidget() == ui_->page_date) ||
+  else if ((ui_->value_stack->currentWidget() == ui_->page_date) ||
       (ui_->value_stack->currentWidget() == ui_->page_date_numeric) ||
       (ui_->value_stack->currentWidget() == ui_->page_date_relative)) {
     QWidget* page = nullptr;
@@ -203,6 +220,7 @@ void SearchTermWidget::OpChanged(int index) {
     }
     ui_->value_stack->setCurrentWidget(page);
   }
+
   emit Changed();
 }
 
@@ -267,7 +285,11 @@ void SearchTermWidget::SetTerm(const SearchTerm& term) {
   // The value depends on the data type
   switch (SearchTerm::TypeOf(term.field_)) {
     case SearchTerm::Type_Text:
-      ui_->value_text->setText(term.value_.toString());
+      if (ui_->value_stack->currentWidget() == ui_->page_empty) {
+        ui_->value_text->setText("");
+      } else {
+        ui_->value_text->setText(term.value_.toString());
+      }
       break;
 
     case SearchTerm::Type_Number:
@@ -313,6 +335,8 @@ SearchTerm SearchTermWidget::Term() const {
   const QWidget* value_page = ui_->value_stack->currentWidget();
   if (value_page == ui_->page_text) {
     ret.value_ = ui_->value_text->text();
+  } else if (value_page == ui_->page_empty) {
+    ret.value_ = "";
   } else if (value_page == ui_->page_number) {
     ret.value_ = ui_->value_number->value();
   } else if (value_page == ui_->page_date) {

src/smartplaylists/searchtermwidget.ui

@@ -71,6 +71,16 @@
              </item>
             </layout>
            </widget>
+           <widget class="QWidget" name="page_empty">
+            <layout class="QVBoxLayout" name="verticalLayout_2">
+             <property name="spacing">
+              <number>0</number>
+             </property>
+             <property name="margin">
+              <number>0</number>
+             </property>
+            </layout>
+           </widget>
            <widget class="QWidget" name="page_rating">
             <layout class="QVBoxLayout" name="verticalLayout_6">
              <property name="spacing">