Hide nghttp2_session_callbacks details and provide setter like functions

To make it possible to add new callbacks without bumping so name, we
decided to hide details of nghttp2_session_callbacks.  We provide
setter like functions to set individual callback function.

examples/client.c

@@ -310,13 +310,21 @@ static int on_data_chunk_recv_callback(nghttp2_session *session, uint8_t flags,
  */
 static void setup_nghttp2_callbacks(nghttp2_session_callbacks *callbacks)
 {
-  memset(callbacks, 0, sizeof(nghttp2_session_callbacks));
+  nghttp2_session_callbacks_set_send_callback(callbacks, send_callback);
-  callbacks->send_callback = send_callback;
+
-  callbacks->recv_callback = recv_callback;
+  nghttp2_session_callbacks_set_recv_callback(callbacks, recv_callback);
-  callbacks->on_frame_send_callback = on_frame_send_callback;
+
-  callbacks->on_frame_recv_callback = on_frame_recv_callback;
+  nghttp2_session_callbacks_set_on_frame_send_callback
-  callbacks->on_stream_close_callback = on_stream_close_callback;
+    (callbacks, on_frame_send_callback);
-  callbacks->on_data_chunk_recv_callback = on_data_chunk_recv_callback;
+
+  nghttp2_session_callbacks_set_on_frame_recv_callback
+    (callbacks, on_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_stream_close_callback
+    (callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
+    (callbacks, on_data_chunk_recv_callback);
 }
 
 /*
@@ -507,7 +515,7 @@ static void request_free(struct Request *req)
  */
 static void fetch_uri(const struct URI *uri)
 {
-  nghttp2_session_callbacks callbacks;
+  nghttp2_session_callbacks *callbacks;
   int fd;
   SSL_CTX *ssl_ctx;
   SSL *ssl;
@@ -519,8 +527,6 @@ static void fetch_uri(const struct URI *uri)
 
   request_init(&req, uri);
 
-  setup_nghttp2_callbacks(&callbacks);
-
   /* Establish connection and setup SSL */
   fd = connect_to(req.host, req.port);
   if(fd == -1) {
@@ -551,8 +557,20 @@ static void fetch_uri(const struct URI *uri)
   set_tcp_nodelay(fd);
 
   printf("[INFO] SSL/TLS handshake completed\n");
-  rv = nghttp2_session_client_new(&connection.session, &callbacks,
+
+  rv = nghttp2_session_callbacks_new(&callbacks);
+
+  if(rv != 0) {
+    diec("nghttp2_session_callbacks_new", rv);
+  }
+
+  setup_nghttp2_callbacks(callbacks);
+
+  rv = nghttp2_session_client_new(&connection.session, callbacks,
                                   &connection);
+
+  nghttp2_session_callbacks_del(callbacks);
+
   if(rv != 0) {
     diec("nghttp2_session_client_new", rv);
   }

examples/libevent-client.c

@@ -331,17 +331,30 @@ static SSL* create_ssl(SSL_CTX *ssl_ctx)
 
 static void initialize_nghttp2_session(http2_session_data *session_data)
 {
-  nghttp2_session_callbacks callbacks;
+  nghttp2_session_callbacks *callbacks;
 
-  memset(&callbacks, 0, sizeof(callbacks));
+  nghttp2_session_callbacks_new(&callbacks);
 
-  callbacks.send_callback = send_callback;
+  nghttp2_session_callbacks_set_send_callback(callbacks, send_callback);
-  callbacks.on_frame_recv_callback = on_frame_recv_callback;
+
-  callbacks.on_data_chunk_recv_callback = on_data_chunk_recv_callback;
+  nghttp2_session_callbacks_set_on_frame_recv_callback
-  callbacks.on_stream_close_callback = on_stream_close_callback;
+    (callbacks, on_frame_recv_callback);
-  callbacks.on_header_callback = on_header_callback;
+
-  callbacks.on_begin_headers_callback = on_begin_headers_callback;
+  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
-  nghttp2_session_client_new(&session_data->session, &callbacks, session_data);
+    (callbacks, on_data_chunk_recv_callback);
+
+  nghttp2_session_callbacks_set_on_stream_close_callback
+    (callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback
+    (callbacks, on_header_callback);
+
+  nghttp2_session_callbacks_set_on_begin_headers_callback
+    (callbacks, on_begin_headers_callback);
+
+  nghttp2_session_client_new(&session_data->session, callbacks, session_data);
+
+  nghttp2_session_callbacks_del(callbacks);
 }
 
 static void send_client_connection_header(http2_session_data *session_data)

examples/libevent-server.c

@@ -555,16 +555,27 @@ static int on_stream_close_callback(nghttp2_session *session,
 
 static void initialize_nghttp2_session(http2_session_data *session_data)
 {
-  nghttp2_session_callbacks callbacks;
+  nghttp2_session_callbacks *callbacks;
 
-  memset(&callbacks, 0, sizeof(callbacks));
+  nghttp2_session_callbacks_new(&callbacks);
 
-  callbacks.send_callback = send_callback;
+  nghttp2_session_callbacks_set_send_callback(callbacks, send_callback);
-  callbacks.on_frame_recv_callback = on_frame_recv_callback;
+
-  callbacks.on_stream_close_callback = on_stream_close_callback;
+  nghttp2_session_callbacks_set_on_frame_recv_callback
-  callbacks.on_header_callback = on_header_callback;
+    (callbacks, on_frame_recv_callback);
-  callbacks.on_begin_headers_callback = on_begin_headers_callback;
+
-  nghttp2_session_server_new(&session_data->session, &callbacks, session_data);
+  nghttp2_session_callbacks_set_on_stream_close_callback
+    (callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback
+    (callbacks, on_header_callback);
+
+  nghttp2_session_callbacks_set_on_begin_headers_callback
+    (callbacks, on_begin_headers_callback);
+
+  nghttp2_session_server_new(&session_data->session, callbacks, session_data);
+
+  nghttp2_session_callbacks_del(callbacks);
 }
 
 /* Send HTTP/2 client connection header, which includes 24 bytes

lib/Makefile.am

@@ -41,7 +41,8 @@ OBJECTS = nghttp2_pq.c nghttp2_map.c nghttp2_queue.c \
 	nghttp2_hd.c nghttp2_hd_huffman.c nghttp2_hd_huffman_data.c \
 	nghttp2_version.c \
 	nghttp2_priority_spec.c \
-	nghttp2_option.c
+	nghttp2_option.c \
+	nghttp2_callbacks.c
 
 HFILES = nghttp2_pq.h nghttp2_int.h nghttp2_map.h nghttp2_queue.h \
 	nghttp2_frame.h \
@@ -52,7 +53,8 @@ HFILES = nghttp2_pq.h nghttp2_int.h nghttp2_map.h nghttp2_queue.h \
 	nghttp2_net.h \
 	nghttp2_hd.h nghttp2_hd_huffman.h \
 	nghttp2_priority_spec.h \
-	nghttp2_option.h
+	nghttp2_option.h \
+	nghttp2_callbacks.h
 
 libnghttp2_la_SOURCES = $(HFILES) $(OBJECTS)
 libnghttp2_la_LDFLAGS = -no-undefined \

lib/includes/nghttp2/nghttp2.h

@@ -1104,6 +1104,9 @@ typedef union {
  * `nghttp2_session_send()` to send data to the remote endpoint.  If
  * the application uses solely `nghttp2_session_mem_send()` instead,
  * this callback function is unnecessary.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_send_callback()`.
  */
 typedef ssize_t (*nghttp2_send_callback)
 (nghttp2_session *session,
@@ -1129,6 +1132,9 @@ typedef ssize_t (*nghttp2_send_callback)
  * `nghttp2_session_recv()` to receive data from the remote endpoint.
  * If the application uses solely `nghttp2_session_mem_recv()`
  * instead, this callback function is unnecessary.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_recv_callback()`.
  */
 typedef ssize_t (*nghttp2_recv_callback)
 (nghttp2_session *session,
@@ -1161,6 +1167,9 @@ typedef ssize_t (*nghttp2_recv_callback)
  * If nonzero value is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_frame_recv_callback()`.
  */
 typedef int (*nghttp2_on_frame_recv_callback)
 (nghttp2_session *session, const nghttp2_frame *frame, void *user_data);
@@ -1184,6 +1193,9 @@ typedef int (*nghttp2_on_frame_recv_callback)
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_invalid_frame_recv_callback()`.
  */
 typedef int (*nghttp2_on_invalid_frame_recv_callback)
 (nghttp2_session *session, const nghttp2_frame *frame,
@@ -1215,6 +1227,9 @@ typedef int (*nghttp2_on_invalid_frame_recv_callback)
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_data_chunk_recv_callback()`.
  */
 typedef int (*nghttp2_on_data_chunk_recv_callback)
 (nghttp2_session *session, uint8_t flags, int32_t stream_id,
@@ -1232,6 +1247,9 @@ typedef int (*nghttp2_on_data_chunk_recv_callback)
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_before_frame_send_callback()`.
  */
 typedef int (*nghttp2_before_frame_send_callback)
 (nghttp2_session *session, const nghttp2_frame *frame, void *user_data);
@@ -1247,6 +1265,9 @@ typedef int (*nghttp2_before_frame_send_callback)
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_frame_send_callback()`.
  */
 typedef int (*nghttp2_on_frame_send_callback)
 (nghttp2_session *session, const nghttp2_frame *frame, void *user_data);
@@ -1265,6 +1286,9 @@ typedef int (*nghttp2_on_frame_send_callback)
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_frame_not_send_callback()`.
  */
 typedef int (*nghttp2_on_frame_not_send_callback)
 (nghttp2_session *session, const nghttp2_frame *frame, int lib_error_code,
@@ -1287,6 +1311,9 @@ typedef int (*nghttp2_on_frame_not_send_callback)
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_stream_close_callback()`.
  */
 typedef int (*nghttp2_on_stream_close_callback)
 (nghttp2_session *session, int32_t stream_id, nghttp2_error_code error_code,
@@ -1309,6 +1336,9 @@ typedef int (*nghttp2_on_stream_close_callback)
  * If nonzero is returned, it is treated as fatal error and
  * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_unknown_frame_recv_callback()`.
  */
 typedef int (*nghttp2_on_unknown_frame_recv_callback)
 (nghttp2_session *session,
@@ -1336,6 +1366,9 @@ typedef int (*nghttp2_on_unknown_frame_recv_callback)
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
  * `nghttp2_session_mem_recv()` function will immediately return
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_begin_headers_callback()`.
  */
 typedef int (*nghttp2_on_begin_headers_callback)
 (nghttp2_session *session, const nghttp2_frame *frame, void *user_data);
@@ -1397,6 +1430,9 @@ typedef int (*nghttp2_on_begin_headers_callback)
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_on_header_callback()`.
  */
 typedef int (*nghttp2_on_header_callback)
 (nghttp2_session *session,
@@ -1419,6 +1455,9 @@ typedef int (*nghttp2_on_header_callback)
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` will make
  * `nghttp2_session_send()` function immediately return
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_select_padding_callback()`.
  */
 typedef ssize_t (*nghttp2_select_padding_callback)
 (nghttp2_session *session,
@@ -1426,85 +1465,183 @@ typedef ssize_t (*nghttp2_select_padding_callback)
  size_t max_payloadlen,
  void *user_data);
 
+struct nghttp2_session_callbacks;
+
 /**
  * @struct
  *
- * Callback functions.
+ * Callback functions for :type:`nghttp2_session`.  The details of
+ * this structure are intentionally hidden from the public API.
  */
-typedef struct {
+typedef struct nghttp2_session_callbacks nghttp2_session_callbacks;
-  /**
+
-   * Callback function invoked when the |session| wants to send data
+/**
-   * to the remote peer.  This callback is not necessary if the
+ * @function
-   * application uses solely `nghttp2_session_mem_send()` to serialize
+ *
-   * data to transmit.
+ * Initializes |*callbacks_ptr| with NULL values.
-   */
+ *
-  nghttp2_send_callback send_callback;
+ * The initialized object can be used when initializing multiple
-  /**
+ * :type:`nghttp2_session` objects.
-   * Callback function invoked when the |session| wants to receive
+ *
-   * data from the remote peer.  This callback is not necessary if the
+ * When the application finished using this object, it can use
-   * application uses solely `nghttp2_session_mem_recv()` to process
+ * `nghttp2_session_callbacks_del()` to free its memory.
-   * received data.
+ *
-   */
+ * This function returns 0 if it succeeds, or one of the following
-  nghttp2_recv_callback recv_callback;
+ * negative error codes:
-  /**
+ *
-   * Callback function invoked by `nghttp2_session_recv()` when a
+ * :enum:`NGHTTP2_ERR_NOMEM`
-   * frame is received.
+ *     Out of memory.
-   */
+ */
-  nghttp2_on_frame_recv_callback on_frame_recv_callback;
+int nghttp2_session_callbacks_new(nghttp2_session_callbacks **callbacks_ptr);
-  /**
+
-   * Callback function invoked by `nghttp2_session_recv()` when an
+/**
-   * invalid non-DATA frame is received.
+ * @function
-   */
+ *
-  nghttp2_on_invalid_frame_recv_callback on_invalid_frame_recv_callback;
+ * Frees any resources allocated for |callbacks|.  If |callbacks| is
-  /**
+ * ``NULL``, this function does nothing.
-   * Callback function invoked when a chunk of data in DATA frame is
+ */
-   * received.
+void nghttp2_session_callbacks_del(nghttp2_session_callbacks *callbacks);
-   */
+
-  nghttp2_on_data_chunk_recv_callback on_data_chunk_recv_callback;
+
-  /**
+/**
-   * Callback function invoked before a non-DATA frame is sent.
+ * @function
-   */
+ *
-  nghttp2_before_frame_send_callback before_frame_send_callback;
+ * Sets callback function invoked when a session wants to send data to
-  /**
+ * the remote peer.  This callback is not necessary if the application
-   * Callback function invoked after a frame is sent.
+ * uses solely `nghttp2_session_mem_send()` to serialize data to
-   */
+ * transmit.
-  nghttp2_on_frame_send_callback on_frame_send_callback;
+ */
-  /**
+void nghttp2_session_callbacks_set_send_callback
-   * The callback function invoked when a non-DATA frame is not sent
+(nghttp2_session_callbacks *cbs, nghttp2_send_callback send_callback);
-   * because of an error.
+
-   */
+/**
-  nghttp2_on_frame_not_send_callback on_frame_not_send_callback;
+ * @function
-  /**
+ *
-   * Callback function invoked when the stream is closed.
+ * Sets callback function invoked when the a session wants to receive
-   */
+ * data from the remote peer.  This callback is not necessary if the
-  nghttp2_on_stream_close_callback on_stream_close_callback;
+ * application uses solely `nghttp2_session_mem_recv()` to process
-  /**
+ * received data.
-   * Callback function invoked when the received frame type is
+ */
-   * unknown.
+void nghttp2_session_callbacks_set_recv_callback
-   */
+(nghttp2_session_callbacks *cbs, nghttp2_recv_callback recv_callback);
-  nghttp2_on_unknown_frame_recv_callback on_unknown_frame_recv_callback;
+
-  /**
+/**
-   * Callback function invoked when the reception of header block in
+ * @function
-   * HEADERS or PUSH_PROMISE is started.
+ *
-   */
+ * Sets callback function invoked by `nghttp2_session_recv()` when a
-  nghttp2_on_begin_headers_callback on_begin_headers_callback;
+ * frame is received.
-  /**
+ */
-   * Callback function invoked when a header name/value pair is
+void nghttp2_session_callbacks_set_on_frame_recv_callback
-   * received.
+(nghttp2_session_callbacks *cbs,
-   */
+ nghttp2_on_frame_recv_callback on_frame_recv_callback);
-  nghttp2_on_header_callback on_header_callback;
+
-  /**
+/**
-   * Callback function invoked when the library asks application how
+ * @function
-   * many padding bytes are required for the transmission of the given
+ *
-   * frame.
+ * Sets callback function invoked by `nghttp2_session_recv()` when an
-   */
+ * invalid non-DATA frame is received.
-  nghttp2_select_padding_callback select_padding_callback;
+ */
-  /**
+void nghttp2_session_callbacks_set_on_invalid_frame_recv_callback
-   * The callback function used to determine the |length| allowed
+(nghttp2_session_callbacks *cbs,
-   * in `nghttp2_data_source_read_callback()`
+ nghttp2_on_invalid_frame_recv_callback on_invalid_frame_recv_callback);
-   */
+
-  nghttp2_data_source_read_length_callback read_length_callback;
+/**
-} nghttp2_session_callbacks;
+ * @function
+ *
+ * Sets callback function invoked when a chunk of data in DATA frame
+ * is received.
+ */
+void nghttp2_session_callbacks_set_on_data_chunk_recv_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_data_chunk_recv_callback on_data_chunk_recv_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked before a non-DATA frame is sent.
+ */
+void nghttp2_session_callbacks_set_before_frame_send_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_before_frame_send_callback before_frame_send_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked after a frame is sent.
+ */
+void nghttp2_session_callbacks_set_on_frame_send_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_frame_send_callback on_frame_send_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when a non-DATA frame is not sent
+ * because of an error.
+ */
+void nghttp2_session_callbacks_set_on_frame_not_send_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_frame_not_send_callback on_frame_not_send_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when the stream is closed.
+ */
+void nghttp2_session_callbacks_set_on_stream_close_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_stream_close_callback on_stream_close_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when the received frame type is
+ * unknown.
+ */
+void nghttp2_session_callbacks_set_on_unknown_frame_recv_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_unknown_frame_recv_callback on_unknown_frame_recv_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when the reception of header block
+ * in HEADERS or PUSH_PROMISE is started.
+ */
+void nghttp2_session_callbacks_set_on_begin_headers_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_begin_headers_callback on_begin_headers_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when a header name/value pair is
+ * received.
+ */
+void nghttp2_session_callbacks_set_on_header_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_header_callback on_header_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when the library asks application
+ * how many padding bytes are required for the transmission of the
+ * given frame.
+ */
+void nghttp2_session_callbacks_set_select_padding_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_select_padding_callback select_padding_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function determine the length allowed in
+ * :type:`nghttp2_data_source_read_callback`.
+ */
+void nghttp2_session_callbacks_set_data_source_read_length_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_data_source_read_length_callback data_source_read_length_callback);
 
 struct nghttp2_option;
 
@@ -1578,10 +1715,10 @@ void nghttp2_option_set_peer_max_concurrent_streams(nghttp2_option *option,
  * does not store |callbacks|.  The |user_data| is an arbitrary user
  * supplied data, which will be passed to the callback functions.
  *
- * The :member:`nghttp2_session_callbacks.send_callback` must be
+ * The :type:`nghttp2_send_callback` must be specified.  If the
- * specified.  If the application code uses `nghttp2_session_recv()`,
+ * application code uses `nghttp2_session_recv()`, the
- * the :member:`nghttp2_session_callbacks.recv_callback` must be
+ * :type:`nghttp2_recv_callback` must be specified.  The other members
- * specified.  The other members of |callbacks| can be ``NULL``.
+ * of |callbacks| can be ``NULL``.
  *
  * If this function fails, |*session_ptr| is left untouched.
  *
@@ -1603,10 +1740,10 @@ int nghttp2_session_client_new(nghttp2_session **session_ptr,
  * does not store |callbacks|.  The |user_data| is an arbitrary user
  * supplied data, which will be passed to the callback functions.
  *
- * The :member:`nghttp2_session_callbacks.send_callback` must be
+ * The :type:`nghttp2_send_callback` must be specified.  If the
- * specified.  If the application code uses `nghttp2_session_recv()`,
+ * application code uses `nghttp2_session_recv()`, the
- * the :member:`nghttp2_session_callbacks.recv_callback` must be
+ * :type:`nghttp2_recv_callback` must be specified.  The other members
- * specified.  The other members of |callbacks| can be ``NULL``.
+ * of |callbacks| can be ``NULL``.
  *
  * If this function fails, |*session_ptr| is left untouched.
  *
@@ -1688,32 +1825,36 @@ void nghttp2_session_del(nghttp2_session *session);
  * This function retrieves the highest prioritized frame from the
  * outbound queue and sends it to the remote peer.  It does this as
  * many as possible until the user callback
- * :member:`nghttp2_session_callbacks.send_callback` returns
+ * :type:`nghttp2_send_callback` returns
  * :enum:`NGHTTP2_ERR_WOULDBLOCK` or the outbound queue becomes empty.
  * This function calls several callback functions which are passed
  * when initializing the |session|.  Here is the simple time chart
  * which tells when each callback is invoked:
  *
  * 1. Get the next frame to send from outbound queue.
+ *
  * 2. Prepare transmission of the frame.
+ *
  * 3. If the control frame cannot be sent because some preconditions
  *    are not met (e.g., request HEADERS cannot be sent after GOAWAY),
- *    :member:`nghttp2_session_callbacks.on_frame_not_send_callback`
+ *    :type:`nghttp2_on_frame_not_send_callback` is invoked.  Abort
- *    is invoked.  Abort the following steps.
+ *    the following steps.
+ *
  * 4. If the frame is HEADERS, PUSH_PROMISE or DATA,
- *    :member:`nghttp2_session_callbacks.select_padding_callback` is
+ *    :type:`nghttp2_select_padding_callback` is invoked.
- *    invoked.
+ *
  * 5. If the frame is request HEADERS, the stream is opened here.
- * 6. :member:`nghttp2_session_callbacks.before_frame_send_callback` is
+ *
- *    invoked.
+ * 6. :type:`nghttp2_before_frame_send_callback` is invoked.
- * 7. :member:`nghttp2_session_callbacks.send_callback` is invoked one
+ *
- *    or more times to send the frame.
+ * 7. :type:`nghttp2_send_callback` is invoked one or more times to
- * 8. :member:`nghttp2_session_callbacks.on_frame_send_callback` is
+ *    send the frame.
- *    invoked.
+ *
+ * 8. :type:`nghttp2_on_frame_send_callback` is invoked.
+ *
  * 9. If the transmission of the frame triggers closure of the stream,
  *    the stream is closed and
- *    :member:`nghttp2_session_callbacks.on_stream_close_callback` is
+ *    :type:`nghttp2_on_stream_close_callback` is invoked.
- *    invoked.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
@@ -1731,11 +1872,10 @@ int nghttp2_session_send(nghttp2_session *session);
  * Returns the serialized data to send.
  *
  * This function behaves like `nghttp2_session_send()` except that it
- * does not use :member:`nghttp2_session_callbacks.send_callback` to
+ * does not use :type:`nghttp2_send_callback` to transmit data.
- * transmit data.  Instead, it assigns the pointer to the serialized
+ * Instead, it assigns the pointer to the serialized data to the
- * data to the |*data_ptr| and returns its length.  The other
+ * |*data_ptr| and returns its length.  The other callbacks are called
- * callbacks are called in the same way as they are in
+ * in the same way as they are in `nghttp2_session_send()`.
- * `nghttp2_session_send()`.
  *
  * If no data is available to send, this function returns 0.
  *
@@ -1765,51 +1905,45 @@ ssize_t nghttp2_session_mem_send(nghttp2_session *session,
  * Receives frames from the remote peer.
  *
  * This function receives as many frames as possible until the user
- * callback :member:`nghttp2_session_callbacks.recv_callback` returns
+ * callback :type:`nghttp2_recv_callback` returns
  * :enum:`NGHTTP2_ERR_WOULDBLOCK`.  This function calls several
  * callback functions which are passed when initializing the
  * |session|.  Here is the simple time chart which tells when each
  * callback is invoked:
  *
- * 1. :member:`nghttp2_session_callbacks.recv_callback` is invoked one
+ * 1. :type:`nghttp2_recv_callback` is invoked one or more times to
- *    or more times to receive frame header.
+ *    receive frame header.
+ *
  * 2. If the frame is DATA frame:
  *
- *    1. :member:`nghttp2_session_callbacks.recv_callback` is invoked
+ *    1. :type:`nghttp2_recv_callback` is invoked to receive DATA
- *       to receive DATA payload. For each chunk of data,
+ *       payload. For each chunk of data,
- *       :member:`nghttp2_session_callbacks.on_data_chunk_recv_callback`
+ *       :type:`nghttp2_on_data_chunk_recv_callback` is invoked.
- *       is invoked.
+ *
  *    2. If one DATA frame is completely received,
- *       :member:`nghttp2_session_callbacks.on_frame_recv_callback` is
+ *       :type:`nghttp2_on_frame_recv_callback` is invoked.  If the
- *       invoked.  If the reception of the frame triggers the
+ *       reception of the frame triggers the closure of the stream,
- *       closure of the stream,
+ *       :type:`nghttp2_on_stream_close_callback` is invoked.
- *       :member:`nghttp2_session_callbacks.on_stream_close_callback`
- *       is invoked.
  *
  * 3. If the frame is the control frame:
  *
- *    1. :member:`nghttp2_session_callbacks.recv_callback` is invoked
+ *    1. :type:`nghttp2_recv_callback` is invoked one or more times to
- *       one or more times to receive whole frame.
+ *       receive whole frame.
  *
  *    2. If the received frame is valid, then following actions are
  *       taken.  If the frame is either HEADERS or PUSH_PROMISE,
- *       :member:`nghttp2_session_callbacks.on_begin_headers_callback`
+ *       :type:`nghttp2_on_begin_headers_callback` is invoked.  Then
- *       is invoked.  Then
+ *       :type:`nghttp2_on_header_callback` is invoked for each header
- *       :member:`nghttp2_session_callbacks.on_header_callback` is
+ *       name/value pair.  After all name/value pairs are emitted
- *       invoked for each header name/value pair.  After all name/value
+ *       successfully, :type:`nghttp2_on_frame_recv_callback` is
- *       pairs are emitted successfully,
- *       :member:`nghttp2_session_callbacks.on_frame_recv_callback` is
  *       invoked.  For other frames,
- *       :member:`nghttp2_session_callbacks.on_frame_recv_callback` is
+ *       :type:`nghttp2_on_frame_recv_callback` is invoked.  If the
- *       invoked.
+ *       reception of the frame triggers the closure of the stream,
- *       If the reception of the frame triggers the closure of the
+ *       :type:`nghttp2_on_stream_close_callback` is invoked.
- *       stream,
+ *
- *       :member:`nghttp2_session_callbacks.on_stream_close_callback`
- *       is invoked.
  *    3. If the received frame is unpacked but is interpreted as
- *       invalid,
+ *       invalid, :type:`nghttp2_on_invalid_frame_recv_callback` is
- *       :member:`nghttp2_session_callbacks.on_invalid_frame_recv_callback`
+ *       invoked.
- *       is invoked.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
@@ -1830,18 +1964,17 @@ int nghttp2_session_recv(nghttp2_session *session);
  * |inlen| indicates the number of bytes in the |in|.
  *
  * This function behaves like `nghttp2_session_recv()` except that it
- * does not use :member:`nghttp2_session_callbacks.recv_callback` to
+ * does not use :type:`nghttp2_recv_callback` to receive data; the
- * receive data; the |in| is the only data for the invocation of this
+ * |in| is the only data for the invocation of this function.  If all
- * function.  If all bytes are processed, this function returns.  The
+ * bytes are processed, this function returns.  The other callbacks
- * other callbacks are called in the same way as they are in
+ * are called in the same way as they are in `nghttp2_session_recv()`.
- * `nghttp2_session_recv()`.
  *
  * In the current implementation, this function always tries to
  * processes all input data unless either an error occurs or
  * :enum:`NGHTTP2_ERR_PAUSE` is returned from
- * :member:`nghttp2_session_callbacks.on_header_callback` or
+ * :type:`nghttp2_on_header_callback` or
- * :member:`nghttp2_session_callbacks.on_data_chunk_recv_callback`.
+ * :type:`nghttp2_on_data_chunk_recv_callback`.  If
- * If :enum:`NGHTTP2_ERR_PAUSE` is used, the return value includes the
+ * :enum:`NGHTTP2_ERR_PAUSE` is used, the return value includes the
  * number of bytes which was used to produce the data or frame for the
  * callback.
  *
@@ -2270,8 +2403,8 @@ int nghttp2_priority_spec_check_default(const nghttp2_priority_spec *pri_spec);
  *   This function returns assigned stream ID if it succeeds.  But
  *   that stream is not opened yet.  The application must not submit
  *   frame to that stream ID before
- *   :member:`nghttp2_session_callbacks.before_frame_send_callback` is
+ *   :type:`nghttp2_before_frame_send_callback` is called for this
- *   called for this frame.
+ *   frame.
  *
  */
 int32_t nghttp2_submit_request(nghttp2_session *session,
@@ -2396,8 +2529,8 @@ int nghttp2_submit_response(nghttp2_session *session,
  *   This function returns assigned stream ID if it succeeds and
  *   |stream_id| is -1.  But that stream is not opened yet.  The
  *   application must not submit frame to that stream ID before
- *   :member:`nghttp2_session_callbacks.before_frame_send_callback` is
+ *   :type:`nghttp2_before_frame_send_callback` is called for this
- *   called for this frame.
+ *   frame.
  *
  */
 int32_t nghttp2_submit_headers(nghttp2_session *session, uint8_t flags,
@@ -2571,8 +2704,8 @@ int nghttp2_submit_settings(nghttp2_session *session, uint8_t flags,
  *   This function returns assigned promised stream ID if it succeeds.
  *   But that stream is not opened yet.  The application must not
  *   submit frame to that stream ID before
- *   :member:`nghttp2_session_callbacks.before_frame_send_callback` is
+ *   :type:`nghttp2_before_frame_send_callback` is called for this
- *   called for this frame.
+ *   frame.
  *
  */
 int32_t nghttp2_submit_push_promise(nghttp2_session *session, uint8_t flags,

lib/nghttp2_callbacks.c

@@ -0,0 +1,139 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2014 Tatsuhiro Tsujikawa
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "nghttp2_callbacks.h"
+
+#include <stdlib.h>
+
+int nghttp2_session_callbacks_new(nghttp2_session_callbacks **callbacks_ptr)
+{
+  *callbacks_ptr = calloc(1, sizeof(nghttp2_session_callbacks));
+
+  if(*callbacks_ptr == NULL) {
+    return NGHTTP2_ERR_NOMEM;
+  }
+
+  return 0;
+}
+
+void nghttp2_session_callbacks_del(nghttp2_session_callbacks *callbacks)
+{
+  free(callbacks);
+}
+
+void nghttp2_session_callbacks_set_send_callback
+(nghttp2_session_callbacks *cbs, nghttp2_send_callback send_callback)
+{
+  cbs->send_callback = send_callback;
+}
+
+void nghttp2_session_callbacks_set_recv_callback
+(nghttp2_session_callbacks *cbs, nghttp2_recv_callback recv_callback)
+{
+  cbs->recv_callback = recv_callback;
+}
+
+void nghttp2_session_callbacks_set_on_frame_recv_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_frame_recv_callback on_frame_recv_callback)
+{
+  cbs->on_frame_recv_callback = on_frame_recv_callback;
+}
+
+void nghttp2_session_callbacks_set_on_invalid_frame_recv_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_invalid_frame_recv_callback on_invalid_frame_recv_callback)
+{
+  cbs->on_invalid_frame_recv_callback = on_invalid_frame_recv_callback;
+}
+
+void nghttp2_session_callbacks_set_on_data_chunk_recv_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_data_chunk_recv_callback on_data_chunk_recv_callback)
+{
+  cbs->on_data_chunk_recv_callback = on_data_chunk_recv_callback;
+}
+
+void nghttp2_session_callbacks_set_before_frame_send_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_before_frame_send_callback before_frame_send_callback)
+{
+  cbs->before_frame_send_callback = before_frame_send_callback;
+}
+
+void nghttp2_session_callbacks_set_on_frame_send_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_frame_send_callback on_frame_send_callback)
+{
+  cbs->on_frame_send_callback = on_frame_send_callback;
+}
+
+void nghttp2_session_callbacks_set_on_frame_not_send_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_frame_not_send_callback on_frame_not_send_callback)
+{
+  cbs->on_frame_not_send_callback = on_frame_not_send_callback;
+}
+
+void nghttp2_session_callbacks_set_on_stream_close_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_stream_close_callback on_stream_close_callback)
+{
+  cbs->on_stream_close_callback = on_stream_close_callback;
+}
+
+void nghttp2_session_callbacks_set_on_unknown_frame_recv_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_unknown_frame_recv_callback on_unknown_frame_recv_callback)
+{
+  cbs->on_unknown_frame_recv_callback = on_unknown_frame_recv_callback;
+}
+
+void nghttp2_session_callbacks_set_on_begin_headers_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_begin_headers_callback on_begin_headers_callback)
+{
+  cbs->on_begin_headers_callback = on_begin_headers_callback;
+}
+
+void nghttp2_session_callbacks_set_on_header_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_on_header_callback on_header_callback)
+{
+  cbs->on_header_callback = on_header_callback;
+}
+
+void nghttp2_session_callbacks_set_select_padding_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_select_padding_callback select_padding_callback)
+{
+  cbs->select_padding_callback = select_padding_callback;
+}
+
+void nghttp2_session_callbacks_set_data_source_read_length_callback
+(nghttp2_session_callbacks *cbs,
+ nghttp2_data_source_read_length_callback data_source_read_length_callback)
+{
+  cbs->read_length_callback = data_source_read_length_callback;
+}

lib/nghttp2_callbacks.h

@@ -0,0 +1,112 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2014 Tatsuhiro Tsujikawa
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef NGHTTP2_CALLBACKS_H
+#define NGHTTP2_CALLBACKS_H
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <nghttp2/nghttp2.h>
+
+/*
+ * Callback functions.
+ */
+struct nghttp2_session_callbacks {
+  /**
+   * Callback function invoked when the session wants to send data to
+   * the remote peer.  This callback is not necessary if the
+   * application uses solely `nghttp2_session_mem_send()` to serialize
+   * data to transmit.
+   */
+  nghttp2_send_callback send_callback;
+  /**
+   * Callback function invoked when the session wants to receive data
+   * from the remote peer.  This callback is not necessary if the
+   * application uses solely `nghttp2_session_mem_recv()` to process
+   * received data.
+   */
+  nghttp2_recv_callback recv_callback;
+  /**
+   * Callback function invoked by `nghttp2_session_recv()` when a
+   * frame is received.
+   */
+  nghttp2_on_frame_recv_callback on_frame_recv_callback;
+  /**
+   * Callback function invoked by `nghttp2_session_recv()` when an
+   * invalid non-DATA frame is received.
+   */
+  nghttp2_on_invalid_frame_recv_callback on_invalid_frame_recv_callback;
+  /**
+   * Callback function invoked when a chunk of data in DATA frame is
+   * received.
+   */
+  nghttp2_on_data_chunk_recv_callback on_data_chunk_recv_callback;
+  /**
+   * Callback function invoked before a non-DATA frame is sent.
+   */
+  nghttp2_before_frame_send_callback before_frame_send_callback;
+  /**
+   * Callback function invoked after a frame is sent.
+   */
+  nghttp2_on_frame_send_callback on_frame_send_callback;
+  /**
+   * The callback function invoked when a non-DATA frame is not sent
+   * because of an error.
+   */
+  nghttp2_on_frame_not_send_callback on_frame_not_send_callback;
+  /**
+   * Callback function invoked when the stream is closed.
+   */
+  nghttp2_on_stream_close_callback on_stream_close_callback;
+  /**
+   * Callback function invoked when the received frame type is
+   * unknown.
+   */
+  nghttp2_on_unknown_frame_recv_callback on_unknown_frame_recv_callback;
+  /**
+   * Callback function invoked when the reception of header block in
+   * HEADERS or PUSH_PROMISE is started.
+   */
+  nghttp2_on_begin_headers_callback on_begin_headers_callback;
+  /**
+   * Callback function invoked when a header name/value pair is
+   * received.
+   */
+  nghttp2_on_header_callback on_header_callback;
+  /**
+   * Callback function invoked when the library asks application how
+   * many padding bytes are required for the transmission of the given
+   * frame.
+   */
+  nghttp2_select_padding_callback select_padding_callback;
+  /**
+   * The callback function used to determine the length allowed in
+   * `nghttp2_data_source_read_callback()`
+   */
+  nghttp2_data_source_read_length_callback read_length_callback;
+};
+
+#endif /* NGHTTP2_CALLBACKS_H */

lib/nghttp2_session.h

@@ -38,6 +38,7 @@
 #include "nghttp2_outbound_item.h"
 #include "nghttp2_int.h"
 #include "nghttp2_buf.h"
+#include "nghttp2_callbacks.h"
 
 /*
  * Option flags.

src/HttpServer.cc

@@ -213,19 +213,29 @@ void remove_stream_write_timeout(Stream *stream)
 }
 } // namespace
 
+namespace {
+void fill_callback(nghttp2_session_callbacks *callbacks, const Config *config);
+} // namespace
+
 class Sessions {
 public:
   Sessions(event_base *evbase, const Config *config, SSL_CTX *ssl_ctx)
     : evbase_(evbase),
       config_(config),
       ssl_ctx_(ssl_ctx),
+      callbacks_(nullptr),
       next_session_id_(1)
-  {}
+  {
+    nghttp2_session_callbacks_new(&callbacks_);
+
+    fill_callback(callbacks_, config_);
+  }
   ~Sessions()
   {
     for(auto handler : handlers_) {
       delete handler;
     }
+    nghttp2_session_callbacks_del(callbacks_);
   }
   void add_handler(Http2Handler *handler)
   {
@@ -269,6 +279,10 @@ public:
     }
     return session_id;
   }
+  const nghttp2_session_callbacks* get_callbacks() const
+  {
+    return callbacks_;
+  }
   void accept_connection(int fd)
   {
     int val = 1;
@@ -297,6 +311,7 @@ private:
   event_base *evbase_;
   const Config *config_;
   SSL_CTX *ssl_ctx_;
+  nghttp2_session_callbacks *callbacks_;
   int64_t next_session_id_;
 };
 
@@ -311,10 +326,6 @@ void on_session_closed(Http2Handler *hd, int64_t session_id)
 }
 } // namespace
 
-namespace {
-void fill_callback(nghttp2_session_callbacks& callbacks, const Config *config);
-} // namespace
-
 Http2Handler::Http2Handler(Sessions *sessions,
                            int fd, SSL *ssl, int64_t session_id)
   : session_id_(session_id),
@@ -724,9 +735,8 @@ void settings_timeout_cb(evutil_socket_t fd, short what, void *arg)
 int Http2Handler::on_connect()
 {
   int r;
-  nghttp2_session_callbacks callbacks;
+
-  fill_callback(callbacks, sessions_->get_config());
+  r = nghttp2_session_server_new(&session_, sessions_->get_callbacks(), this);
-  r = nghttp2_session_server_new(&session_, &callbacks, this);
   if(r != 0) {
     return r;
   }
@@ -1436,23 +1446,37 @@ int on_stream_close_callback
 } // namespace
 
 namespace {
-void fill_callback(nghttp2_session_callbacks& callbacks, const Config *config)
+void fill_callback(nghttp2_session_callbacks *callbacks, const Config *config)
 {
-  memset(&callbacks, 0, sizeof(nghttp2_session_callbacks));
+  nghttp2_session_callbacks_set_on_stream_close_callback
-  callbacks.on_stream_close_callback = on_stream_close_callback;
+    (callbacks, on_stream_close_callback);
-  callbacks.on_frame_recv_callback = hd_on_frame_recv_callback;
+
-  callbacks.on_frame_send_callback = hd_on_frame_send_callback;
+  nghttp2_session_callbacks_set_on_frame_recv_callback
+    (callbacks, hd_on_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_frame_send_callback
+    (callbacks, hd_on_frame_send_callback);
+
   if(config->verbose) {
-    callbacks.on_invalid_frame_recv_callback =
+    nghttp2_session_callbacks_set_on_invalid_frame_recv_callback
-      verbose_on_invalid_frame_recv_callback;
+      (callbacks, verbose_on_invalid_frame_recv_callback);
-    callbacks.on_unknown_frame_recv_callback =
+
-      verbose_on_unknown_frame_recv_callback;
+    nghttp2_session_callbacks_set_on_unknown_frame_recv_callback
+      (callbacks, verbose_on_unknown_frame_recv_callback);
   }
-  callbacks.on_data_chunk_recv_callback = on_data_chunk_recv_callback;
+
-  callbacks.on_header_callback = on_header_callback;
+  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
-  callbacks.on_begin_headers_callback = on_begin_headers_callback;
+    (callbacks, on_data_chunk_recv_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback
+    (callbacks, on_header_callback);
+
+  nghttp2_session_callbacks_set_on_begin_headers_callback
+    (callbacks, on_begin_headers_callback);
+
   if(config->padding) {
-    callbacks.select_padding_callback = select_padding_callback;
+    nghttp2_session_callbacks_set_select_padding_callback
+      (callbacks, select_padding_callback);
   }
 }
 } // namespace

src/h2load_http2_session.cc

@@ -102,13 +102,26 @@ void Http2Session::on_connect()
 {
   int rv;
 
-  nghttp2_session_callbacks callbacks = {0};
+  nghttp2_session_callbacks *callbacks;
-  callbacks.on_frame_recv_callback = on_frame_recv_callback;
-  callbacks.on_data_chunk_recv_callback = on_data_chunk_recv_callback;
-  callbacks.on_stream_close_callback = on_stream_close_callback;
-  callbacks.on_header_callback = on_header_callback;
 
-  nghttp2_session_client_new(&session_, &callbacks, client_);
+  nghttp2_session_callbacks_new(&callbacks);
+
+  util::auto_delete<nghttp2_session_callbacks*> callbacks_deleter
+    (callbacks, nghttp2_session_callbacks_del);
+
+  nghttp2_session_callbacks_set_on_frame_recv_callback
+    (callbacks, on_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
+    (callbacks, on_data_chunk_recv_callback);
+
+  nghttp2_session_callbacks_set_on_stream_close_callback
+    (callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback
+    (callbacks, on_header_callback);
+
+  nghttp2_session_client_new(&session_, callbacks, client_);
 
   nghttp2_settings_entry iv[2];
   iv[0].settings_id = NGHTTP2_SETTINGS_ENABLE_PUSH;

src/nghttp.cc

@@ -1829,22 +1829,41 @@ ssize_t file_read_callback
 namespace {
 int run(char **uris, int n)
 {
-  nghttp2_session_callbacks callbacks;
+  nghttp2_session_callbacks *callbacks;
-  memset(&callbacks, 0, sizeof(nghttp2_session_callbacks));
+
-  callbacks.on_stream_close_callback = on_stream_close_callback;
+  nghttp2_session_callbacks_new(&callbacks);
-  callbacks.on_frame_recv_callback = on_frame_recv_callback2;
+  util::auto_delete<nghttp2_session_callbacks*> cbsdel
+    (callbacks, nghttp2_session_callbacks_del);
+
+  nghttp2_session_callbacks_set_on_stream_close_callback
+    (callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_frame_recv_callback
+    (callbacks, on_frame_recv_callback2);
+
   if(config.verbose) {
-    callbacks.on_frame_send_callback = verbose_on_frame_send_callback;
+    nghttp2_session_callbacks_set_on_frame_send_callback
-    callbacks.on_invalid_frame_recv_callback =
+      (callbacks, verbose_on_frame_send_callback);
-      verbose_on_invalid_frame_recv_callback;
+
-    callbacks.on_unknown_frame_recv_callback =
+    nghttp2_session_callbacks_set_on_invalid_frame_recv_callback
-      verbose_on_unknown_frame_recv_callback;
+      (callbacks, verbose_on_invalid_frame_recv_callback);
+
+    nghttp2_session_callbacks_set_on_unknown_frame_recv_callback
+      (callbacks, verbose_on_unknown_frame_recv_callback);
   }
-  callbacks.on_data_chunk_recv_callback = on_data_chunk_recv_callback;
+
-  callbacks.on_begin_headers_callback = on_begin_headers_callback;
+  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
-  callbacks.on_header_callback = on_header_callback;
+    (callbacks, on_data_chunk_recv_callback);
+
+  nghttp2_session_callbacks_set_on_begin_headers_callback
+    (callbacks, on_begin_headers_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback
+    (callbacks, on_header_callback);
+
   if(config.padding) {
-    callbacks.select_padding_callback = select_padding_callback;
+    nghttp2_session_callbacks_set_select_padding_callback
+      (callbacks, select_padding_callback);
   }
 
   std::string prev_scheme;
@@ -1886,7 +1905,7 @@ int run(char **uris, int n)
          port != prev_port) {
         if(!requests.empty()) {
           if (communicate(prev_scheme, prev_host, prev_port,
-                          std::move(requests), &callbacks) != 0) {
+                          std::move(requests), callbacks) != 0) {
             ++failures;
           }
           requests.clear();
@@ -1901,7 +1920,7 @@ int run(char **uris, int n)
   }
   if(!requests.empty()) {
     if (communicate(prev_scheme, prev_host, prev_port, std::move(requests),
-                    &callbacks) != 0) {
+                    callbacks) != 0) {
       ++failures;
     }
   }

src/shrpx_http2_session.cc

@@ -1390,21 +1390,46 @@ int Http2Session::on_connect()
       return -1;
     }
   }
-  nghttp2_session_callbacks callbacks;
+  nghttp2_session_callbacks *callbacks;
-  memset(&callbacks, 0, sizeof(callbacks));
+  rv = nghttp2_session_callbacks_new(&callbacks);
-  callbacks.on_stream_close_callback = on_stream_close_callback;
+
-  callbacks.on_frame_recv_callback = on_frame_recv_callback;
+  if(rv != 0) {
-  callbacks.on_data_chunk_recv_callback = on_data_chunk_recv_callback;
+    return -1;
-  callbacks.on_frame_send_callback = on_frame_send_callback;
-  callbacks.on_frame_not_send_callback = on_frame_not_send_callback;
-  callbacks.on_unknown_frame_recv_callback = on_unknown_frame_recv_callback;
-  callbacks.on_header_callback = on_header_callback;
-  callbacks.on_begin_headers_callback = on_begin_headers_callback;
-  if(get_config()->padding) {
-    callbacks.select_padding_callback = http::select_padding_callback;
   }
 
-  rv = nghttp2_session_client_new2(&session_, &callbacks, this,
+  util::auto_delete<nghttp2_session_callbacks*> callbacks_deleter
+    (callbacks, nghttp2_session_callbacks_del);
+
+  nghttp2_session_callbacks_set_on_stream_close_callback
+    (callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_frame_recv_callback
+    (callbacks, on_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
+    (callbacks, on_data_chunk_recv_callback);
+
+  nghttp2_session_callbacks_set_on_frame_send_callback
+    (callbacks, on_frame_send_callback);
+
+  nghttp2_session_callbacks_set_on_frame_not_send_callback
+    (callbacks, on_frame_not_send_callback);
+
+  nghttp2_session_callbacks_set_on_unknown_frame_recv_callback
+    (callbacks, on_unknown_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback
+    (callbacks, on_header_callback);
+
+  nghttp2_session_callbacks_set_on_begin_headers_callback
+    (callbacks, on_begin_headers_callback);
+
+  if(get_config()->padding) {
+    nghttp2_session_callbacks_set_select_padding_callback
+      (callbacks, http::select_padding_callback);
+  }
+
+  rv = nghttp2_session_client_new2(&session_, callbacks, this,
                                    get_config()->http2_option);
 
   if(rv != 0) {

src/shrpx_http2_upstream.cc

@@ -645,22 +645,46 @@ Http2Upstream::Http2Upstream(ClientHandler *handler)
   handler->set_upstream_timeouts(&get_config()->http2_upstream_read_timeout,
                                  &get_config()->upstream_write_timeout);
 
-  nghttp2_session_callbacks callbacks;
+  int rv;
-  memset(&callbacks, 0, sizeof(callbacks));
+
-  callbacks.on_stream_close_callback = on_stream_close_callback;
+  nghttp2_session_callbacks *callbacks;
-  callbacks.on_frame_recv_callback = on_frame_recv_callback;
+  rv = nghttp2_session_callbacks_new(&callbacks);
-  callbacks.on_data_chunk_recv_callback = on_data_chunk_recv_callback;
+
-  callbacks.on_frame_send_callback = on_frame_send_callback;
+  assert(rv == 0);
-  callbacks.on_frame_not_send_callback = on_frame_not_send_callback;
+
-  callbacks.on_unknown_frame_recv_callback = on_unknown_frame_recv_callback;
+  util::auto_delete<nghttp2_session_callbacks*> callbacks_deleter
-  callbacks.on_header_callback = on_header_callback;
+    (callbacks, nghttp2_session_callbacks_del);
-  callbacks.on_begin_headers_callback = on_begin_headers_callback;
+
+  nghttp2_session_callbacks_set_on_stream_close_callback
+    (callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_frame_recv_callback
+    (callbacks, on_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
+    (callbacks, on_data_chunk_recv_callback);
+
+  nghttp2_session_callbacks_set_on_frame_send_callback
+    (callbacks, on_frame_send_callback);
+
+  nghttp2_session_callbacks_set_on_frame_not_send_callback
+    (callbacks, on_frame_not_send_callback);
+
+  nghttp2_session_callbacks_set_on_unknown_frame_recv_callback
+    (callbacks, on_unknown_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback
+    (callbacks, on_header_callback);
+
+  nghttp2_session_callbacks_set_on_begin_headers_callback
+    (callbacks, on_begin_headers_callback);
+
   if(get_config()->padding) {
-    callbacks.select_padding_callback = http::select_padding_callback;
+    nghttp2_session_callbacks_set_select_padding_callback
+      (callbacks, http::select_padding_callback);
   }
 
-  int rv;
+  rv = nghttp2_session_server_new2(&session_, callbacks, this,
-  rv = nghttp2_session_server_new2(&session_, &callbacks, this,
                                    get_config()->http2_option);
 
   assert(rv == 0);