Utils: Add isEmpty to string view

Change-Id: Ib7e77602dcdcdf481f6ab690bacef53c5dd92580
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/smallstringview.h

@@ -85,6 +85,12 @@ public:
         return m_size;
     }
 
+    constexpr
+    size_type isEmpty() const
+    {
+        return m_size == 0;
+    }
+
     const_iterator begin() const noexcept
     {
         return data();

tests/unit/unittest/smallstring-test.cpp

@@ -731,6 +731,12 @@ TEST(SmallString, IsEmpty)
     ASSERT_TRUE(SmallString().isEmpty());
 }
 
+TEST(SmallString, StringViewIsEmpty)
+{
+    ASSERT_FALSE(SmallStringView("text").isEmpty());
+    ASSERT_TRUE(SmallStringView("").isEmpty());
+}
+
 TEST(SmallString, HasContent)
 {
     ASSERT_TRUE(SmallString("text").hasContent());