FTL: Fix SmallMap<K, V, 0>::try_emplace
SmallVector<T, N>::emplace_back returns a reference, whereas
SmallVector<T, 0>::emplace_back returns an iterator (because
its API must be compatible with StaticVector).
Bug: 185536303
Test: ftl_test
Change-Id: I6bdcd983c0bb2d2a326f79906997f85e89d7df44
diff --git a/include/ftl/small_map.h b/include/ftl/small_map.h
index 49cde7f..83d5967 100644
--- a/include/ftl/small_map.h
+++ b/include/ftl/small_map.h
@@ -107,12 +107,20 @@
template <typename Q, typename W, std::size_t M, typename E>
SmallMap(SmallMap<Q, W, M, E> other) : map_(std::move(other.map_)) {}
+ static constexpr size_type static_capacity() { return N; }
+
size_type max_size() const { return map_.max_size(); }
size_type size() const { return map_.size(); }
bool empty() const { return map_.empty(); }
// Returns whether the map is backed by static or dynamic storage.
- bool dynamic() const { return map_.dynamic(); }
+ bool dynamic() const {
+ if constexpr (static_capacity() > 0) {
+ return map_.dynamic();
+ } else {
+ return true;
+ }
+ }
iterator begin() { return map_.begin(); }
const_iterator begin() const { return cbegin(); }
@@ -171,9 +179,15 @@
return {it, false};
}
- auto& ref = map_.emplace_back(std::piecewise_construct, std::forward_as_tuple(key),
- std::forward_as_tuple(std::forward<Args>(args)...));
- return {&ref, true};
+ decltype(auto) ref_or_it =
+ map_.emplace_back(std::piecewise_construct, std::forward_as_tuple(key),
+ std::forward_as_tuple(std::forward<Args>(args)...));
+
+ if constexpr (static_capacity() > 0) {
+ return {&ref_or_it, true};
+ } else {
+ return {ref_or_it, true};
+ }
}
// Replaces a mapping if it exists, and returns an iterator to it. Returns the end() iterator
diff --git a/libs/ftl/small_map_test.cpp b/libs/ftl/small_map_test.cpp
index 634877f..e96d70d 100644
--- a/libs/ftl/small_map_test.cpp
+++ b/libs/ftl/small_map_test.cpp
@@ -189,9 +189,20 @@
}
}
-TEST(SmallMap, TryEmplace) {
- SmallMap<int, std::string, 3> map;
- using Pair = decltype(map)::value_type;
+template <typename Capacity>
+struct SmallMapTest : testing::Test {
+ static constexpr std::size_t kCapacity = Capacity{}();
+};
+
+template <std::size_t N>
+using Capacity = std::integral_constant<std::size_t, N>;
+
+using Capacities = testing::Types<Capacity<3>, Capacity<0>>;
+TYPED_TEST_SUITE(SmallMapTest, Capacities, );
+
+TYPED_TEST(SmallMapTest, TryEmplace) {
+ SmallMap<int, std::string, TestFixture::kCapacity> map;
+ using Pair = typename decltype(map)::value_type;
{
const auto [it, ok] = map.try_emplace(123, "abc");
@@ -207,14 +218,22 @@
const auto [it, ok] = map.try_emplace(-1);
ASSERT_TRUE(ok);
EXPECT_EQ(*it, Pair(-1, std::string()));
- EXPECT_FALSE(map.dynamic());
+ if constexpr (map.static_capacity() > 0) {
+ EXPECT_FALSE(map.dynamic());
+ } else {
+ EXPECT_TRUE(map.dynamic());
+ }
}
{
// Insertion fails if mapping exists.
const auto [it, ok] = map.try_emplace(42, "!!!");
EXPECT_FALSE(ok);
EXPECT_EQ(*it, Pair(42, "???"));
- EXPECT_FALSE(map.dynamic());
+ if constexpr (map.static_capacity() > 0) {
+ EXPECT_FALSE(map.dynamic());
+ } else {
+ EXPECT_TRUE(map.dynamic());
+ }
}
{
// Insertion at capacity promotes the map.
@@ -240,9 +259,9 @@
} // namespace
-TEST(SmallMap, TryReplace) {
- SmallMap<int, String, 3> map = ftl::init::map(1, "a")(2, "B");
- using Pair = decltype(map)::value_type;
+TYPED_TEST(SmallMapTest, TryReplace) {
+ SmallMap<int, String, TestFixture::kCapacity> map = ftl::init::map(1, "a")(2, "B");
+ using Pair = typename decltype(map)::value_type;
{
// Replacing fails unless mapping exists.
@@ -260,7 +279,12 @@
EXPECT_EQ(*it, Pair(2, "b"));
}
- EXPECT_FALSE(map.dynamic());
+ if constexpr (map.static_capacity() > 0) {
+ EXPECT_FALSE(map.dynamic());
+ } else {
+ EXPECT_TRUE(map.dynamic());
+ }
+
EXPECT_TRUE(map.try_emplace(3, "abc").second);
EXPECT_TRUE(map.try_emplace(4, "d").second);
EXPECT_TRUE(map.dynamic());
@@ -284,9 +308,9 @@
EXPECT_EQ(map, SmallMap(ftl::init::map(4, "d"s)(3, "c"s)(2, "b"s)(1, "a"s)));
}
-TEST(SmallMap, EmplaceOrReplace) {
- SmallMap<int, String, 3> map = ftl::init::map(1, "a")(2, "B");
- using Pair = decltype(map)::value_type;
+TYPED_TEST(SmallMapTest, EmplaceOrReplace) {
+ SmallMap<int, String, TestFixture::kCapacity> map = ftl::init::map(1, "a")(2, "B");
+ using Pair = typename decltype(map)::value_type;
{
// New mapping is emplaced.
@@ -305,7 +329,12 @@
EXPECT_EQ(*it, Pair(2, "b"));
}
- EXPECT_FALSE(map.dynamic());
+ if constexpr (map.static_capacity() > 0) {
+ EXPECT_FALSE(map.dynamic());
+ } else {
+ EXPECT_TRUE(map.dynamic());
+ }
+
EXPECT_FALSE(map.emplace_or_replace(3, "abc").second); // Replace.
EXPECT_TRUE(map.emplace_or_replace(4, "d").second); // Emplace.
EXPECT_TRUE(map.dynamic());