collection_type_impl: add to_value(mutation_view)

Allows collapsing a mutation into a literal.

types.cc

@@ -825,6 +825,18 @@ map_type_impl::serialized_values(std::vector<atomic_cell::one> cells) {
     abort();
 }
 
+bytes
+map_type_impl::to_value(mutation_view mut, int protocol_version) {
+    std::vector<bytes_view> tmp;
+    tmp.reserve(mut.size() * 2);
+    for (auto&& e : mut) {
+        if (e.second.is_live()) {
+            tmp.emplace_back(e.first);
+            tmp.emplace_back(e.second.value());
+        }
+    }
+    return pack(tmp.begin(), tmp.end(), tmp.size() / 2, protocol_version);
+}
 
 bytes
 map_type_impl::serialize_partially_deserialized_form(
@@ -1084,6 +1096,18 @@ set_type_impl::serialized_values(std::vector<atomic_cell::one> cells) {
     abort();
 }
 
+bytes
+set_type_impl::to_value(mutation_view mut, int protocol_version) {
+    std::vector<bytes_view> tmp;
+    tmp.reserve(mut.size());
+    for (auto&& e : mut) {
+        if (e.second.is_live()) {
+            tmp.emplace_back(e.first);
+        }
+    }
+    return pack(tmp.begin(), tmp.end(), tmp.size(), protocol_version);
+}
+
 list_type
 list_type_impl::get_instance(data_type elements, bool is_multi_cell) {
     return intern::get_instance(elements, is_multi_cell);
@@ -1211,6 +1235,18 @@ list_type_impl::serialized_values(std::vector<atomic_cell::one> cells) {
     abort();
 }
 
+bytes
+list_type_impl::to_value(mutation_view mut, int protocol_version) {
+    std::vector<bytes_view> tmp;
+    tmp.reserve(mut.size());
+    for (auto&& e : mut) {
+        if (e.second.is_live()) {
+            tmp.emplace_back(e.second.value());
+        }
+    }
+    return pack(tmp.begin(), tmp.end(), tmp.size(), protocol_version);
+}
+
 thread_local const shared_ptr<abstract_type> int32_type(make_shared<int32_type_impl>());
 thread_local const shared_ptr<abstract_type> long_type(make_shared<long_type_impl>());
 thread_local const shared_ptr<abstract_type> ascii_type(make_shared<string_type_impl>("ascii", cql3::native_cql3_type::ascii));

types.hh

@@ -203,6 +203,7 @@ public:
     template <typename BytesViewIterator>
     static bytes pack(BytesViewIterator start, BytesViewIterator finish, int elements, int version);
     mutation_view deserialize_mutation_form(bytes_view in);
+    virtual bytes to_value(mutation_view mut, int protocol_version) = 0;
     // FIXME: use iterators?
     collection_mutation::one serialize_mutation_form(const mutation& mut);
     collection_mutation::one serialize_mutation_form(mutation_view mut);
@@ -290,6 +291,7 @@ public:
     virtual std::vector<bytes> serialized_values(std::vector<atomic_cell::one> cells) override;
     static bytes serialize_partially_deserialized_form(const std::vector<std::pair<bytes_view, bytes_view>>& v,
             int protocol_version);
+    virtual bytes to_value(mutation_view mut, int protocol_version) override;
 };
 
 using map_type = shared_ptr<map_type_impl>;
@@ -322,6 +324,7 @@ public:
     virtual size_t hash(bytes_view v) override;
     virtual bytes from_string(sstring_view text) override;
     virtual std::vector<bytes> serialized_values(std::vector<atomic_cell::one> cells) override;
+    virtual bytes to_value(mutation_view mut, int protocol_version) override;
 };
 
 using set_type = shared_ptr<set_type_impl>;
@@ -354,6 +357,7 @@ public:
     virtual size_t hash(bytes_view v) override;
     virtual bytes from_string(sstring_view text) override;
     virtual std::vector<bytes> serialized_values(std::vector<atomic_cell::one> cells) override;
+    virtual bytes to_value(mutation_view mut, int protocol_version) override;
 };
 
 using list_type = shared_ptr<list_type_impl>;