lib/graph/connection.c

   1 /*
   2  * Copyright 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #define BT_LOG_TAG "CONNECTION"
  26 #include <babeltrace/lib-logging-internal.h>
  27
  28 #include <babeltrace/graph/notification-iterator-internal.h>
  29 #include <babeltrace/graph/component-internal.h>
  30 #include <babeltrace/graph/connection-internal.h>
  31 #include <babeltrace/graph/connection-const.h>
  32 #include <babeltrace/graph/graph-internal.h>
  33 #include <babeltrace/graph/port-internal.h>
  34 #include <babeltrace/object-internal.h>
  35 #include <babeltrace/compiler-internal.h>
  36 #include <babeltrace/object.h>
  37 #include <babeltrace/assert-internal.h>
  38 #include <babeltrace/assert-pre-internal.h>
  39 #include <stdlib.h>
  40 #include <glib.h>
  41
  42 static
  43 void destroy_connection(struct bt_object *obj)
  44 {
  45         struct bt_connection *connection = container_of(obj,
  46                         struct bt_connection, base);
  47
  48         BT_LIB_LOGD("Destroying connection: %!+x", connection);
  49
  50         /*
  51          * Make sure that each notification iterator which was created
  52          * for this connection is finalized before we destroy it. Once a
  53          * notification iterator is finalized, all its method return
  54          * NULL or the BT_NOTIFICATION_ITERATOR_STATUS_CANCELED status.
  55          *
  56          * Because connections are destroyed before components within a
  57          * graph, this ensures that notification iterators are always
  58          * finalized before their upstream component.
  59          *
  60          * Ending the connection does exactly this. We pass `false` to
  61          * bt_connection_end() here to avoid removing this connection
  62          * from the graph: if we're here, we're already in the graph's
  63          * destructor.
  64          */
  65         bt_connection_end(connection, false);
  66         g_ptr_array_free(connection->iterators, TRUE);
  67         connection->iterators = NULL;
  68
  69         /*
  70          * No bt_object_put_ref on ports as a connection only holds _weak_
  71          * references to them.
  72          */
  73         g_free(connection);
  74 }
  75
  76 static
  77 void try_remove_connection_from_graph(struct bt_connection *connection)
  78 {
  79         void *graph = (void *) bt_object_borrow_parent(&connection->base);
  80
  81         if (connection->base.ref_count > 0 ||
  82                         connection->downstream_port ||
  83                         connection->upstream_port ||
  84                         connection->iterators->len > 0) {
  85                 return;
  86         }
  87
  88         /*
  89          * At this point we know that:
  90          *
  91          * 1. The connection is ended (ports were disconnected).
  92          * 2. All the notification iterators that this connection
  93          *    created, if any, are finalized.
  94          * 3. The connection's reference count is 0, so only the
  95          *    parent (graph) owns this connection after this call.
  96          *
  97          * In other words, no other object than the graph knows this
  98          * connection.
  99          *
 100          * It is safe to remove the connection from the graph, therefore
 101          * destroying it.
 102          */
 103         BT_LIB_LOGD("Removing self from graph's connections: "
 104                 "%![graph-]+g, %![conn-]+x", graph, connection);
 105         bt_graph_remove_connection(graph, connection);
 106 }
 107
 108 static
 109 void parent_is_owner(struct bt_object *obj)
 110 {
 111         struct bt_connection *connection = container_of(obj,
 112                         struct bt_connection, base);
 113
 114         try_remove_connection_from_graph(connection);
 115 }
 116
 117 BT_HIDDEN
 118 struct bt_connection *bt_connection_create(struct bt_graph *graph,
 119                 struct bt_port *upstream_port,
 120                 struct bt_port *downstream_port)
 121 {
 122         struct bt_connection *connection = NULL;
 123
 124         BT_LIB_LOGD("Creating connection: "
 125                 "%![graph-]+g, %![up-port-]+p, %![down-port-]+p",
 126                 graph, upstream_port, downstream_port);
 127         connection = g_new0(struct bt_connection, 1);
 128         if (!connection) {
 129                 BT_LOGE_STR("Failed to allocate one connection.");
 130                 goto end;
 131         }
 132
 133         bt_object_init_shared_with_parent(&connection->base,
 134                 destroy_connection);
 135         bt_object_set_parent_is_owner_listener_func(&connection->base,
 136                 parent_is_owner);
 137         connection->iterators = g_ptr_array_new();
 138         if (!connection->iterators) {
 139                 BT_LOGE_STR("Failed to allocate a GPtrArray.");
 140                 BT_OBJECT_PUT_REF_AND_RESET(connection);
 141                 goto end;
 142         }
 143
 144         /* Weak references are taken, see comment in header. */
 145         connection->upstream_port = upstream_port;
 146         connection->downstream_port = downstream_port;
 147         BT_LIB_LOGD("Setting upstream port's connection: %!+p", upstream_port);
 148         bt_port_set_connection(upstream_port, connection);
 149         BT_LIB_LOGD("Setting downstream port's connection: %!+p",
 150                 downstream_port);
 151         bt_port_set_connection(downstream_port, connection);
 152         bt_object_set_parent(&connection->base, &graph->base);
 153         BT_LIB_LOGD("Created connection: %!+x", connection);
 154
 155 end:
 156         return connection;
 157 }
 158
 159 BT_HIDDEN
 160 void bt_connection_end(struct bt_connection *conn, bool try_remove_from_graph)
 161 {
 162         struct bt_component *downstream_comp = NULL;
 163         struct bt_component *upstream_comp = NULL;
 164         struct bt_port *downstream_port = conn->downstream_port;
 165         struct bt_port *upstream_port = conn->upstream_port;
 166         struct bt_graph *graph = bt_connection_borrow_graph(conn);
 167         size_t i;
 168
 169         BT_LIB_LOGD("Ending connection: %!+x, try-remove-from-graph=%d",
 170                 conn, try_remove_from_graph);
 171
 172         /*
 173          * Any of the following notification callback functions could
 174          * remove one of the connection's ports from its component. To
 175          * make sure that at least logging in called functions works
 176          * with existing objects, get a local reference on both ports.
 177          */
 178         bt_object_get_ref(downstream_port);
 179         bt_object_get_ref(upstream_port);
 180
 181         if (downstream_port) {
 182                 BT_LIB_LOGD("Disconnecting connection's downstream port: %!+p",
 183                         downstream_port);
 184                 downstream_comp = bt_port_borrow_component_inline(
 185                         downstream_port);
 186                 bt_port_set_connection(downstream_port, NULL);
 187                 conn->downstream_port = NULL;
 188         }
 189
 190         if (upstream_port) {
 191                 BT_LIB_LOGD("Disconnecting connection's upstream port: %!+p",
 192                         upstream_port);
 193                 upstream_comp = bt_port_borrow_component_inline(
 194                         upstream_port);
 195                 bt_port_set_connection(upstream_port, NULL);
 196                 conn->upstream_port = NULL;
 197         }
 198
 199         if (downstream_comp && conn->notified_downstream_port_connected &&
 200                         !conn->notified_downstream_port_disconnected) {
 201                 /* bt_component_port_disconnected() logs details */
 202                 bt_component_port_disconnected(downstream_comp,
 203                         downstream_port);
 204                 conn->notified_downstream_port_disconnected = true;
 205         }
 206
 207         if (upstream_comp && conn->notified_upstream_port_connected &&
 208                         !conn->notified_upstream_port_disconnected) {
 209                 /* bt_component_port_disconnected() logs details */
 210                 bt_component_port_disconnected(upstream_comp, upstream_port);
 211                 conn->notified_upstream_port_disconnected = true;
 212         }
 213
 214         BT_ASSERT(graph);
 215
 216         if (conn->notified_graph_ports_connected &&
 217                         !conn->notified_graph_ports_disconnected) {
 218                 /* bt_graph_notify_ports_disconnected() logs details */
 219                 bt_graph_notify_ports_disconnected(graph, upstream_comp,
 220                         downstream_comp, upstream_port, downstream_port);
 221                 conn->notified_graph_ports_disconnected = true;
 222         }
 223
 224         /*
 225          * It is safe to put the local port references now that we don't
 226          * need them anymore. This could indeed destroy them.
 227          */
 228         bt_object_put_ref(downstream_port);
 229         bt_object_put_ref(upstream_port);
 230
 231         /*
 232          * Because this connection is ended, finalize (cancel) each
 233          * notification iterator created from it.
 234          */
 235         for (i = 0; i < conn->iterators->len; i++) {
 236                 struct bt_self_component_port_input_notification_iterator *iterator =
 237                         g_ptr_array_index(conn->iterators, i);
 238
 239                 BT_LIB_LOGD("Finalizing notification iterator created by "
 240                         "this ended connection: %![iter-]+i", iterator);
 241                 bt_self_component_port_input_notification_iterator_finalize(
 242                         iterator);
 243
 244                 /*
 245                  * Make sure this iterator does not try to remove itself
 246                  * from this connection's iterators on destruction
 247                  * because this connection won't exist anymore.
 248                  */
 249                 bt_self_component_port_input_notification_iterator_set_connection(
 250                         iterator, NULL);
 251         }
 252
 253         g_ptr_array_set_size(conn->iterators, 0);
 254
 255         if (try_remove_from_graph) {
 256                 try_remove_connection_from_graph(conn);
 257         }
 258 }
 259
 260 const struct bt_port_output *bt_connection_borrow_upstream_port_const(
 261                 const struct bt_connection *connection)
 262 {
 263         BT_ASSERT_PRE_NON_NULL(connection, "Connection");
 264         return (void *) connection->upstream_port;
 265 }
 266
 267 const struct bt_port_input *bt_connection_borrow_downstream_port_const(
 268                 const struct bt_connection *connection)
 269 {
 270         BT_ASSERT_PRE_NON_NULL(connection, "Connection");
 271         return (void *) connection->downstream_port;
 272 }
 273
 274 BT_HIDDEN
 275 void bt_connection_remove_iterator(struct bt_connection *conn,
 276                 struct bt_self_component_port_input_notification_iterator *iterator)
 277 {
 278         g_ptr_array_remove(conn->iterators, iterator);
 279         BT_LIB_LOGV("Removed notification iterator from connection: "
 280                 "%![conn-]+x, %![iter-]+i", conn, iterator);
 281         try_remove_connection_from_graph(conn);
 282 }
 283
 284 bt_bool bt_connection_is_ended(const struct bt_connection *connection)
 285 {
 286         return !connection->downstream_port && !connection->upstream_port;
 287 }