[Minor] Remove optional as function_view has nullable semantics

diff --git a/src/libmime/mime_string.hxx b/src/libmime/mime_string.hxx
index 2ebf8a29a887c9b8c45eea80cd163eabaf49abca..c15dfd5664cdba36aded9adfe074d88a820176c3 100644 (file)
--- a/src/libmime/mime_string.hxx
+++ b/src/libmime/mime_string.hxx
@@ -20,7 +20,6 @@
 #include <string>
 #include <string_view>
 #include <memory>
-#include <optional>
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>
@@ -89,6 +88,14 @@ public:
                                          const Allocator& alloc = Allocator()) noexcept :
                        basic_mime_string(st.data(), st.size(), alloc) {}
 
+       /**
+        * Creates a string with a filter function. It is calee responsibility to
+        * ensure that the filter functor survives long enough to work with a string
+        * @param str
+        * @param sz
+        * @param filt
+        * @param alloc
+        */
        basic_mime_string(const T* str, std::size_t sz,
                                          filter_type &&filt,
                                          const Allocator& alloc = Allocator()) noexcept :
@@ -132,7 +139,7 @@ public:
         * @return
         */
        [[nodiscard]] auto assign_if_valid(storage_type &&other) -> bool {
-               if (filter_func.has_value()) {
+               if (filter_func) {
                        /* No way */
                        return false;
                }
@@ -153,7 +160,7 @@ public:
        auto assign_copy(const storage_type &other) {
                storage.clear();
 
-               if (filter_func.has_value()) {
+               if (filter_func) {
                        append_c_string_filtered(other.data(), other.size());
                }
                else {
@@ -162,7 +169,7 @@ public:
        }
 
        auto append(const T* str, std::size_t size) -> std::size_t {
-               if (filter_func.has_value()) {
+               if (filter_func) {
                        return append_c_string_filtered(str, size);
                }
                else {
@@ -204,7 +211,7 @@ public:
 private:
        mime_string_flags flags = mime_string_flags::MIME_STRING_DEFAULT;
        storage_type storage;
-       std::optional<filter_type> filter_func;
+       filter_type filter_func;
 
        auto append_c_string_unfiltered(const T* str, std::size_t len) -> std::size_t {
                /* This is fast path */
@@ -268,8 +275,8 @@ private:
                                flags = flags | mime_string_flags::MIME_STRING_SEEN_INVALID;
                        }
                        else {
-                               if (filter_func.has_value()) {
-                                       uc = filter_func.value()(uc);
+                               if (filter_func) {
+                                       uc = filter_func(uc);
                                }
 
                                if (uc == 0) {