Utils: Add intializer_list constructor in SmallString

You can now write

SmallString text = {"Oh ", women[4], " how much I miss you"};

if it can be casted to SmallStringView.

Change-Id: I86b69ee8d735017cac4391e7c4e68355eb5f227b
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/smallstring.h

@@ -40,6 +40,8 @@
 #include <cstdlib>
 #include <climits>
 #include <cstring>
+#include <initializer_list>
+#include <numeric>
 #include <string>
 #include <unordered_map>
 #include <utility>
@@ -135,6 +137,28 @@ public:
     {
     }
 
+    BasicSmallString(std::initializer_list<Utils::SmallStringView> list)
+    {
+        std::size_t size = std::accumulate(list.begin(),
+                                           list.end(),
+                                           std::size_t(0),
+                                           [] (std::size_t size, Utils::SmallStringView string) {
+                return size + string.size();
+         });
+
+        reserve(size);
+        setSize(size);
+
+        char *currentData = data();
+
+        for (Utils::SmallStringView string : list) {
+            std::memcpy(currentData, string.data(), string.size());
+
+            currentData += string.size();
+        }
+
+        at(size) = 0;
+    }
 
     ~BasicSmallString() noexcept
     {

tests/unit/unittest/smallstring-test.cpp

@@ -1186,3 +1186,45 @@ TEST(SmallString, ManipulateNonConstSubscriptOperator)
 
     ASSERT_THAT(text, SmallString{"some qext"});
 }
+
+TEST(SmallString, EmptyInitializerListContent)
+{
+    SmallString text = {};
+
+    ASSERT_THAT(text, SmallString());
+}
+
+TEST(SmallString, EmptyInitializerListSize)
+{
+    SmallString text = {};
+
+    ASSERT_THAT(text, SizeIs(0));
+}
+
+TEST(SmallString, EmptyInitializerListNullTerminated)
+{
+    auto end = SmallString{{}}[0];
+
+    ASSERT_THAT(end, '\0');
+}
+
+TEST(SmallString, InitializerListContent)
+{
+    SmallString text = {"some", " ", "text"};
+
+    ASSERT_THAT(text, SmallString("some text"));
+}
+
+TEST(SmallString, InitializerListSize)
+{
+    SmallString text = {"some", " ", "text"};
+
+    ASSERT_THAT(text, SizeIs(9));
+}
+
+TEST(SmallString, InitializerListNullTerminated)
+{
+    auto end = SmallString{"some", " ", "text"}[9];
+
+    ASSERT_THAT(end, '\0');
+}