feat: parsers are default constructible

include/boost/http_proto/parser.hpp

@@ -614,16 +614,11 @@ class parser
     friend class response_parser;
     class impl;
 
-    BOOST_HTTP_PROTO_DECL
-    parser(
-        const rts::context&,
-        detail::kind);
-
-    BOOST_HTTP_PROTO_DECL
-    parser(parser&& other) noexcept;
-
-    BOOST_HTTP_PROTO_DECL
-    ~parser();
+    BOOST_HTTP_PROTO_DECL ~parser();
+    BOOST_HTTP_PROTO_DECL parser() noexcept;
+    BOOST_HTTP_PROTO_DECL parser(parser&& other) noexcept;
+    BOOST_HTTP_PROTO_DECL parser(rts::context const&, detail::kind);
+    BOOST_HTTP_PROTO_DECL void assign(parser&& other) noexcept;
 
     BOOST_HTTP_PROTO_DECL
     void

include/boost/http_proto/request_parser.hpp

@@ -43,6 +43,62 @@ class request_parser
         }
     };
 
+    /** Destructor.
+
+        Any views or buffers obtained from this
+        parser become invalid.
+    */
+    ~request_parser() = default;
+
+    /** Constructor.
+
+        Default-constructed parsers do not reference any
+        implementation and therefore must be assigned to before using.
+    */
+    request_parser() noexcept = default;
+
+    /** Constructor.
+
+        The states of `other` are transferred
+        to the newly constructed object,
+        including the allocated buffer.
+        After construction, the only valid
+        operations on the moved-from object
+        are destruction and assignment.
+
+        Buffer sequences previously obtained
+        using @ref prepare or @ref pull_body
+        remain valid.
+
+        @par Complexity
+        Constant.
+
+        @param other The parser to move from.
+    */
+    request_parser(
+        request_parser&& other) noexcept = default;
+
+    /** Assignment.
+        The states of `other` are transferred
+        to this object, including the allocated
+        buffer.
+        After assignment, the only valid
+        operations on the moved-from object
+        are destruction and assignment.
+        Buffer sequences previously obtained
+        using @ref prepare or @ref pull_body
+        remain valid.
+        @par Complexity
+        Constant.
+        @param other The parser to move from.
+    */
+    request_parser&
+    operator=(request_parser&& other) noexcept
+    {
+        assign(std::move(other));
+        return *this;
+    }
+
     /** Constructor.
 
         Constructs a parser that uses the @ref
@@ -84,35 +140,7 @@ class request_parser
     */
     BOOST_HTTP_PROTO_DECL
     explicit
-    request_parser(const rts::context& ctx);
-
-    /** Constructor.
-
-        The states of `other` are transferred
-        to the newly constructed object,
-        including the allocated buffer.
-        After construction, the only valid
-        operations on the moved-from object
-        are destruction and assignment.
-
-        Buffer sequences previously obtained
-        using @ref prepare or @ref pull_body
-        remain valid.
-
-        @par Complexity
-        Constant.
-
-        @param other The parser to move from.
-    */
-    request_parser(
-        request_parser&& other) noexcept = default;
-
-    /** Destructor.
-
-        Any views or buffers obtained from this
-        parser become invalid.
-    */
-    ~request_parser() = default;
+    request_parser(rts::context const& ctx);
 
     /** Return a reference to the parsed request headers.
 

include/boost/http_proto/response_parser.hpp

@@ -43,6 +43,62 @@ class response_parser
         }
     };
 
+    /** Destructor.
+
+        Any views or buffers obtained from this
+        parser become invalid.
+    */
+    ~response_parser() = default;
+
+    /** Constructor.
+
+        Default-constructed parsers do not reference any
+        implementation and therefore must be assigned to before using.
+    */
+    response_parser() = default;
+
+    /** Constructor.
+
+        The states of `other` are transferred
+        to the newly constructed object,
+        including the allocated buffer.
+        After construction, the only valid
+        operations on the moved-from object
+        are destruction and assignemt.
+
+        Buffer sequences previously obtained
+        using @ref prepare or @ref pull_body
+        remain valid.
+
+        @par Complexity
+        Constant.
+
+        @param other The parser to move from.
+    */
+    response_parser(
+        response_parser&& other) noexcept = default;
+
+    /** Assignment.
+        The states of `other` are transferred
+        to this object, including the allocated
+        buffer.
+        After assignment, the only valid
+        operations on the moved-from object
+        are destruction and assignment.
+        Buffer sequences previously obtained
+        using @ref prepare or @ref pull_body
+        remain valid.
+        @par Complexity
+        Constant.
+        @param other The parser to move from.
+    */
+    response_parser&
+    operator=(response_parser&& other) noexcept
+    {
+        assign(std::move(other));
+        return *this;
+    }
+
     /** Constructor.
 
         Constructs a parser that uses the @ref
@@ -84,35 +140,7 @@ class response_parser
     */
     BOOST_HTTP_PROTO_DECL
     explicit
-    response_parser(const rts::context& ctx);
-
-    /** Constructor.
-
-        The states of `other` are transferred
-        to the newly constructed object,
-        including the allocated buffer.
-        After construction, the only valid
-        operations on the moved-from object
-        are destruction and assignemt.
-
-        Buffer sequences previously obtained
-        using @ref prepare or @ref pull_body
-        remain valid.
-
-        @par Complexity
-        Constant.
-
-        @param other The parser to move from.
-    */
-    response_parser(
-        response_parser&& other) noexcept = default;
-
-    /** Destructor.
-
-        Any views or buffers obtained from this
-        parser become invalid.
-    */
-    ~response_parser() = default;
+    response_parser(rts::context const& ctx);
 
     /** Prepare for the next message on the stream.
 

include/boost/http_proto/serializer.hpp

@@ -66,6 +66,63 @@ class serializer
     using const_buffers_type =
         boost::span<buffers::const_buffer const>;
 
+    /** Destructor
+    */
+    BOOST_HTTP_PROTO_DECL
+    ~serializer();
+
+    /** Constructor
+        Default-constructed serializers do not reference any implementation;
+        the only valid operations are destruction and assignment.
+    */
+    serializer() = default;
+
+    /** Constructor.
+
+        The states of `other` are transferred
+        to the newly constructed object,
+        which includes the allocated buffer.
+        After construction, the only valid
+        operations on the moved-from object
+        are destruction and assignment.
+
+        Buffer sequences previously obtained
+        using @ref prepare or @ref stream::prepare
+        remain valid.
+
+        @par Postconditions
+        @code
+        other.is_done() == true
+        @endcode
+
+        @par Complexity
+        Constant.
+
+        @param other The serializer to move from.
+    */
+    BOOST_HTTP_PROTO_DECL
+    serializer(
+        serializer&& other) noexcept;
+
+    /** Assignment.
+        The states of `other` are transferred
+        to this object, which includes the
+        allocated buffer. After assignment,
+        the only valid operations on the
+        moved-from object are destruction and
+        assignment.
+        Buffer sequences previously obtained
+        using @ref prepare or @ref stream::prepare
+        remain valid.
+        @par Complexity
+        Constant.
+        @param other The serializer to move from.
+        @return A reference to this object.
+    */
+    BOOST_HTTP_PROTO_DECL
+    serializer&
+    operator=(serializer&& other) noexcept;
+
     /** Constructor.
 
         Constructs a serializer that uses the @ref
@@ -116,38 +173,6 @@ class serializer
     serializer(
         const rts::context& ctx);
 
-    /** Constructor.
-
-        The states of `other` are transferred
-        to the newly constructed object,
-        which includes the allocated buffer.
-        After construction, the only valid
-        operations on the moved-from object
-        are destruction and assignment.
-
-        Buffer sequences previously obtained
-        using @ref prepare or @ref stream::prepare
-        remain valid.
-
-        @par Postconditions
-        @code
-        other.is_done() == true
-        @endcode
-
-        @par Complexity
-        Constant.
-
-        @param other The serializer to move from.
-    */
-    BOOST_HTTP_PROTO_DECL
-    serializer(
-        serializer&& other) noexcept;
-
-    /** Destructor
-    */
-    BOOST_HTTP_PROTO_DECL
-    ~serializer();
-
     /** Reset the serializer for a new message.
 
         Aborts any ongoing serialization and
@@ -536,7 +561,7 @@ class serializer
         message_base const&,
         source&);
 
-    impl* impl_;
+    impl* impl_ = nullptr;
 };
 
 /** Serializer configuration settings.

src/parser.cpp

@@ -1848,11 +1848,15 @@ class parser::impl
 //------------------------------------------------
 
 parser::
-parser(const rts::context& ctx, detail::kind k)
-    : impl_(new impl(ctx, k))
+~parser()
+{
+    delete impl_;
+}
+
+parser::
+parser() noexcept
+    : impl_(nullptr)
 {
-    // TODO: use a single allocation for
-    // impl and workspace buffer.
 }
 
 parser::
@@ -1863,9 +1867,24 @@ parser(parser&& other) noexcept
 }
 
 parser::
-~parser()
+parser(
+    rts::context const& ctx,
+    detail::kind k)
+    : impl_(new impl(ctx, k))
+{
+    // TODO: use a single allocation for
+    // impl and workspace buffer.
+}
+
+void
+parser::
+assign(parser&& other) noexcept
 {
+    if(this == &other)
+        return;
     delete impl_;
+    impl_ = other.impl_;
+    other.impl_ = nullptr;
 }
 
 //--------------------------------------------