| 1 | /* |
| 2 | * SPDX-License-Identifier: MIT |
| 3 | * |
| 4 | * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com> |
| 5 | * Copyright 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 6 | */ |
| 7 | |
| 8 | #define BT_LOG_TAG "LIB/CONNECTION" |
| 9 | #include "lib/logging.h" |
| 10 | |
| 11 | #include "common/assert.h" |
| 12 | #include "lib/assert-cond.h" |
| 13 | #include <babeltrace2/graph/connection.h> |
| 14 | #include "lib/object.h" |
| 15 | #include "compat/compiler.h" |
| 16 | #include <stdbool.h> |
| 17 | #include <stdlib.h> |
| 18 | #include <glib.h> |
| 19 | |
| 20 | #include "component.h" |
| 21 | #include "connection.h" |
| 22 | #include "graph.h" |
| 23 | #include "message/iterator.h" |
| 24 | #include "port.h" |
| 25 | |
| 26 | static |
| 27 | void destroy_connection(struct bt_object *obj) |
| 28 | { |
| 29 | struct bt_connection *connection = container_of(obj, |
| 30 | struct bt_connection, base); |
| 31 | |
| 32 | BT_LIB_LOGI("Destroying connection: %!+x", connection); |
| 33 | |
| 34 | /* |
| 35 | * Make sure that each message iterator which was created for |
| 36 | * this connection is finalized before we destroy it. Once a |
| 37 | * message iterator is finalized, you cannot use it. |
| 38 | * |
| 39 | * Because connections are destroyed before components within a |
| 40 | * graph, this ensures that message iterators are always |
| 41 | * finalized before their upstream component. |
| 42 | * |
| 43 | * Ending the connection does exactly this. We pass `false` to |
| 44 | * bt_connection_end() here to avoid removing this connection |
| 45 | * from the graph: if we're here, we're already in the graph's |
| 46 | * destructor. |
| 47 | */ |
| 48 | bt_connection_end(connection, false); |
| 49 | g_ptr_array_free(connection->iterators, TRUE); |
| 50 | connection->iterators = NULL; |
| 51 | |
| 52 | /* |
| 53 | * No bt_object_put_ref on ports as a connection only holds _weak_ |
| 54 | * references to them. |
| 55 | */ |
| 56 | g_free(connection); |
| 57 | } |
| 58 | |
| 59 | static |
| 60 | void try_remove_connection_from_graph(struct bt_connection *connection) |
| 61 | { |
| 62 | void *graph = (void *) bt_object_borrow_parent(&connection->base); |
| 63 | |
| 64 | if (connection->base.ref_count > 0 || |
| 65 | connection->downstream_port || |
| 66 | connection->upstream_port || |
| 67 | connection->iterators->len > 0) { |
| 68 | return; |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * At this point we know that: |
| 73 | * |
| 74 | * 1. The connection is ended (ports were disconnected). |
| 75 | * 2. All the message iterators that this connection |
| 76 | * created, if any, are finalized. |
| 77 | * 3. The connection's reference count is 0, so only the |
| 78 | * parent (graph) owns this connection after this call. |
| 79 | * |
| 80 | * In other words, no other object than the graph knows this |
| 81 | * connection. |
| 82 | * |
| 83 | * It is safe to remove the connection from the graph, therefore |
| 84 | * destroying it. |
| 85 | */ |
| 86 | BT_LIB_LOGD("Removing self from graph's connections: " |
| 87 | "%![graph-]+g, %![conn-]+x", graph, connection); |
| 88 | bt_graph_remove_connection(graph, connection); |
| 89 | } |
| 90 | |
| 91 | static |
| 92 | void parent_is_owner(struct bt_object *obj) |
| 93 | { |
| 94 | struct bt_connection *connection = container_of(obj, |
| 95 | struct bt_connection, base); |
| 96 | |
| 97 | try_remove_connection_from_graph(connection); |
| 98 | } |
| 99 | |
| 100 | BT_HIDDEN |
| 101 | struct bt_connection *bt_connection_create(struct bt_graph *graph, |
| 102 | struct bt_port *upstream_port, |
| 103 | struct bt_port *downstream_port) |
| 104 | { |
| 105 | struct bt_connection *connection = NULL; |
| 106 | |
| 107 | BT_LIB_LOGI("Creating connection: " |
| 108 | "%![graph-]+g, %![up-port-]+p, %![down-port-]+p", |
| 109 | graph, upstream_port, downstream_port); |
| 110 | connection = g_new0(struct bt_connection, 1); |
| 111 | if (!connection) { |
| 112 | BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate one connection."); |
| 113 | goto end; |
| 114 | } |
| 115 | |
| 116 | bt_object_init_shared_with_parent(&connection->base, |
| 117 | destroy_connection); |
| 118 | bt_object_set_parent_is_owner_listener_func(&connection->base, |
| 119 | parent_is_owner); |
| 120 | connection->iterators = g_ptr_array_new(); |
| 121 | if (!connection->iterators) { |
| 122 | BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate a GPtrArray."); |
| 123 | BT_OBJECT_PUT_REF_AND_RESET(connection); |
| 124 | goto end; |
| 125 | } |
| 126 | |
| 127 | /* Weak references are taken, see comment in header. */ |
| 128 | connection->upstream_port = upstream_port; |
| 129 | connection->downstream_port = downstream_port; |
| 130 | BT_LIB_LOGD("Setting upstream port's connection: %!+p", upstream_port); |
| 131 | bt_port_set_connection(upstream_port, connection); |
| 132 | BT_LIB_LOGD("Setting downstream port's connection: %!+p", |
| 133 | downstream_port); |
| 134 | bt_port_set_connection(downstream_port, connection); |
| 135 | bt_object_set_parent(&connection->base, &graph->base); |
| 136 | BT_LIB_LOGI("Created connection: %!+x", connection); |
| 137 | |
| 138 | end: |
| 139 | return connection; |
| 140 | } |
| 141 | |
| 142 | BT_HIDDEN |
| 143 | void bt_connection_end(struct bt_connection *conn, bool try_remove_from_graph) |
| 144 | { |
| 145 | struct bt_port *downstream_port = conn->downstream_port; |
| 146 | struct bt_port *upstream_port = conn->upstream_port; |
| 147 | size_t i; |
| 148 | |
| 149 | BT_LIB_LOGI("Ending connection: %!+x, try-remove-from-graph=%d", |
| 150 | conn, try_remove_from_graph); |
| 151 | |
| 152 | /* |
| 153 | * Any of the following message callback functions could |
| 154 | * remove one of the connection's ports from its component. To |
| 155 | * make sure that at least logging in called functions works |
| 156 | * with existing objects, get a local reference on both ports. |
| 157 | */ |
| 158 | bt_object_get_ref(downstream_port); |
| 159 | bt_object_get_ref(upstream_port); |
| 160 | |
| 161 | if (downstream_port) { |
| 162 | BT_LIB_LOGD("Disconnecting connection's downstream port: %!+p", |
| 163 | downstream_port); |
| 164 | bt_port_set_connection(downstream_port, NULL); |
| 165 | conn->downstream_port = NULL; |
| 166 | } |
| 167 | |
| 168 | if (upstream_port) { |
| 169 | BT_LIB_LOGD("Disconnecting connection's upstream port: %!+p", |
| 170 | upstream_port); |
| 171 | bt_port_set_connection(upstream_port, NULL); |
| 172 | conn->upstream_port = NULL; |
| 173 | } |
| 174 | |
| 175 | /* |
| 176 | * It is safe to put the local port references now that we don't |
| 177 | * need them anymore. This could indeed destroy them. |
| 178 | */ |
| 179 | bt_object_put_ref(downstream_port); |
| 180 | bt_object_put_ref(upstream_port); |
| 181 | |
| 182 | /* |
| 183 | * Because this connection is ended, finalize each message |
| 184 | * iterator created from it. |
| 185 | * |
| 186 | * In practice, this only happens when the connection is |
| 187 | * destroyed and not all its message iterators were finalized, |
| 188 | * which is on graph destruction. |
| 189 | */ |
| 190 | for (i = 0; i < conn->iterators->len; i++) { |
| 191 | struct bt_message_iterator *iterator = |
| 192 | g_ptr_array_index(conn->iterators, i); |
| 193 | |
| 194 | BT_LIB_LOGD("Finalizing message iterator created by " |
| 195 | "this ended connection: %![iter-]+i", iterator); |
| 196 | bt_message_iterator_try_finalize( |
| 197 | iterator); |
| 198 | |
| 199 | /* |
| 200 | * Make sure this iterator does not try to remove itself |
| 201 | * from this connection's iterators on destruction |
| 202 | * because this connection won't exist anymore. |
| 203 | */ |
| 204 | bt_message_iterator_set_connection( |
| 205 | iterator, NULL); |
| 206 | } |
| 207 | |
| 208 | g_ptr_array_set_size(conn->iterators, 0); |
| 209 | |
| 210 | if (try_remove_from_graph) { |
| 211 | try_remove_connection_from_graph(conn); |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | const struct bt_port_output *bt_connection_borrow_upstream_port_const( |
| 216 | const struct bt_connection *connection) |
| 217 | { |
| 218 | BT_ASSERT_PRE_DEV_CONN_NON_NULL(connection); |
| 219 | return (void *) connection->upstream_port; |
| 220 | } |
| 221 | |
| 222 | const struct bt_port_input *bt_connection_borrow_downstream_port_const( |
| 223 | const struct bt_connection *connection) |
| 224 | { |
| 225 | BT_ASSERT_PRE_DEV_CONN_NON_NULL(connection); |
| 226 | return (void *) connection->downstream_port; |
| 227 | } |
| 228 | |
| 229 | BT_HIDDEN |
| 230 | void bt_connection_remove_iterator(struct bt_connection *conn, |
| 231 | struct bt_message_iterator *iterator) |
| 232 | { |
| 233 | g_ptr_array_remove(conn->iterators, iterator); |
| 234 | BT_LIB_LOGD("Removed message iterator from connection: " |
| 235 | "%![conn-]+x, %![iter-]+i", conn, iterator); |
| 236 | try_remove_connection_from_graph(conn); |
| 237 | } |
| 238 | |
| 239 | void bt_connection_get_ref(const struct bt_connection *connection) |
| 240 | { |
| 241 | bt_object_get_ref(connection); |
| 242 | } |
| 243 | |
| 244 | void bt_connection_put_ref(const struct bt_connection *connection) |
| 245 | { |
| 246 | bt_object_put_ref(connection); |
| 247 | } |