Document libbabeltrace2's C API
[babeltrace.git] / src / lib / graph / connection.c
CommitLineData
784cdc68 1/*
f2b0325d 2 * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
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3 * Copyright 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 *
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy
6 * of this software and associated documentation files (the "Software"), to deal
7 * in the Software without restriction, including without limitation the rights
8 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 * copies of the Software, and to permit persons to whom the Software is
10 * furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 * SOFTWARE.
22 */
23
b03487ab 24#define BT_LOG_TAG "LIB/CONNECTION"
1633ef46 25#include "lib/logging.h"
a36bfb16 26
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27#include "common/assert.h"
28#include "lib/assert-pre.h"
0341b021 29#include "lib/assert-post.h"
7704a0af 30#include <babeltrace2/graph/connection.h>
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31#include "lib/object.h"
32#include "compat/compiler.h"
969c1d8a 33#include <stdbool.h>
0fbb9a9f 34#include <stdlib.h>
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35#include <glib.h>
36
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37#include "component.h"
38#include "connection.h"
39#include "graph.h"
40#include "message/iterator.h"
41#include "port.h"
42
784cdc68 43static
834e9996 44void destroy_connection(struct bt_object *obj)
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45{
46 struct bt_connection *connection = container_of(obj,
47 struct bt_connection, base);
bd14d768 48
a684a357 49 BT_LIB_LOGI("Destroying connection: %!+x", connection);
a36bfb16 50
bd14d768 51 /*
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52 * Make sure that each message iterator which was created for
53 * this connection is finalized before we destroy it. Once a
d73bb381 54 * message iterator is finalized, you cannot use it.
bd14d768
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55 *
56 * Because connections are destroyed before components within a
b09a5592 57 * graph, this ensures that message iterators are always
bd14d768 58 * finalized before their upstream component.
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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.
bd14d768 64 */
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65 bt_connection_end(connection, false);
66 g_ptr_array_free(connection->iterators, TRUE);
834e9996 67 connection->iterators = NULL;
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68
69 /*
8138bfe1 70 * No bt_object_put_ref on ports as a connection only holds _weak_
c42ea0af 71 * references to them.
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72 */
73 g_free(connection);
74}
75
f167d3c0 76static
834e9996 77void try_remove_connection_from_graph(struct bt_connection *connection)
f167d3c0 78{
1d7bf349 79 void *graph = (void *) bt_object_borrow_parent(&connection->base);
f167d3c0 80
1d7bf349 81 if (connection->base.ref_count > 0 ||
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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 *
a36bfb16 91 * 1. The connection is ended (ports were disconnected).
b09a5592 92 * 2. All the message iterators that this connection
f167d3c0
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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 */
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103 BT_LIB_LOGD("Removing self from graph's connections: "
104 "%![graph-]+g, %![conn-]+x", graph, connection);
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105 bt_graph_remove_connection(graph, connection);
106}
107
108static
834e9996 109void parent_is_owner(struct bt_object *obj)
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110{
111 struct bt_connection *connection = container_of(obj,
112 struct bt_connection, base);
113
834e9996 114 try_remove_connection_from_graph(connection);
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115}
116
784cdc68 117BT_HIDDEN
834e9996 118struct bt_connection *bt_connection_create(struct bt_graph *graph,
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119 struct bt_port *upstream_port,
120 struct bt_port *downstream_port)
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121{
122 struct bt_connection *connection = NULL;
123
a684a357 124 BT_LIB_LOGI("Creating connection: "
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125 "%![graph-]+g, %![up-port-]+p, %![down-port-]+p",
126 graph, upstream_port, downstream_port);
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127 connection = g_new0(struct bt_connection, 1);
128 if (!connection) {
a8f90e5d 129 BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate one connection.");
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130 goto end;
131 }
132
1d7bf349 133 bt_object_init_shared_with_parent(&connection->base,
834e9996 134 destroy_connection);
1d7bf349 135 bt_object_set_parent_is_owner_listener_func(&connection->base,
834e9996 136 parent_is_owner);
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137 connection->iterators = g_ptr_array_new();
138 if (!connection->iterators) {
a8f90e5d 139 BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate a GPtrArray.");
8138bfe1 140 BT_OBJECT_PUT_REF_AND_RESET(connection);
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141 goto end;
142 }
143
784cdc68 144 /* Weak references are taken, see comment in header. */
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145 connection->upstream_port = upstream_port;
146 connection->downstream_port = downstream_port;
834e9996 147 BT_LIB_LOGD("Setting upstream port's connection: %!+p", upstream_port);
72b913fb 148 bt_port_set_connection(upstream_port, connection);
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149 BT_LIB_LOGD("Setting downstream port's connection: %!+p",
150 downstream_port);
72b913fb 151 bt_port_set_connection(downstream_port, connection);
1d7bf349 152 bt_object_set_parent(&connection->base, &graph->base);
a684a357 153 BT_LIB_LOGI("Created connection: %!+x", connection);
a36bfb16 154
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155end:
156 return connection;
157}
158
72b913fb 159BT_HIDDEN
834e9996 160void bt_connection_end(struct bt_connection *conn, bool try_remove_from_graph)
72b913fb 161{
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162 struct bt_port *downstream_port = conn->downstream_port;
163 struct bt_port *upstream_port = conn->upstream_port;
f167d3c0 164 size_t i;
72b913fb 165
a684a357 166 BT_LIB_LOGI("Ending connection: %!+x, try-remove-from-graph=%d",
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167 conn, try_remove_from_graph);
168
834e9996 169 /*
b09a5592 170 * Any of the following message callback functions could
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171 * remove one of the connection's ports from its component. To
172 * make sure that at least logging in called functions works
173 * with existing objects, get a local reference on both ports.
174 */
175 bt_object_get_ref(downstream_port);
176 bt_object_get_ref(upstream_port);
177
72b913fb 178 if (downstream_port) {
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179 BT_LIB_LOGD("Disconnecting connection's downstream port: %!+p",
180 downstream_port);
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181 bt_port_set_connection(downstream_port, NULL);
182 conn->downstream_port = NULL;
183 }
184
185 if (upstream_port) {
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186 BT_LIB_LOGD("Disconnecting connection's upstream port: %!+p",
187 upstream_port);
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188 bt_port_set_connection(upstream_port, NULL);
189 conn->upstream_port = NULL;
190 }
191
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192 /*
193 * It is safe to put the local port references now that we don't
194 * need them anymore. This could indeed destroy them.
195 */
196 bt_object_put_ref(downstream_port);
197 bt_object_put_ref(upstream_port);
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198
199 /*
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200 * Because this connection is ended, finalize each message
201 * iterator created from it.
202 *
203 * In practice, this only happens when the connection is
204 * destroyed and not all its message iterators were finalized,
205 * which is on graph destruction.
f167d3c0
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206 */
207 for (i = 0; i < conn->iterators->len; i++) {
fbd8a4e0 208 struct bt_message_iterator *iterator =
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209 g_ptr_array_index(conn->iterators, i);
210
b09a5592 211 BT_LIB_LOGD("Finalizing message iterator created by "
834e9996 212 "this ended connection: %![iter-]+i", iterator);
fbd8a4e0 213 bt_message_iterator_try_finalize(
834e9996 214 iterator);
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215
216 /*
217 * Make sure this iterator does not try to remove itself
218 * from this connection's iterators on destruction
219 * because this connection won't exist anymore.
220 */
fbd8a4e0 221 bt_message_iterator_set_connection(
fe7265b5 222 iterator, NULL);
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223 }
224
225 g_ptr_array_set_size(conn->iterators, 0);
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226
227 if (try_remove_from_graph) {
834e9996 228 try_remove_connection_from_graph(conn);
c42ea0af 229 }
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230}
231
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232const struct bt_port_output *bt_connection_borrow_upstream_port_const(
233 const struct bt_connection *connection)
784cdc68 234{
fa6cfec3 235 BT_ASSERT_PRE_DEV_NON_NULL(connection, "Connection");
834e9996 236 return (void *) connection->upstream_port;
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237}
238
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239const struct bt_port_input *bt_connection_borrow_downstream_port_const(
240 const struct bt_connection *connection)
784cdc68 241{
fa6cfec3 242 BT_ASSERT_PRE_DEV_NON_NULL(connection, "Connection");
834e9996 243 return (void *) connection->downstream_port;
784cdc68 244}
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245
246BT_HIDDEN
247void bt_connection_remove_iterator(struct bt_connection *conn,
fbd8a4e0 248 struct bt_message_iterator *iterator)
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249{
250 g_ptr_array_remove(conn->iterators, iterator);
a684a357 251 BT_LIB_LOGD("Removed message iterator from connection: "
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252 "%![conn-]+x, %![iter-]+i", conn, iterator);
253 try_remove_connection_from_graph(conn);
bd14d768 254}
090a4c0a 255
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256void bt_connection_get_ref(const struct bt_connection *connection)
257{
258 bt_object_get_ref(connection);
259}
260
261void bt_connection_put_ref(const struct bt_connection *connection)
262{
263 bt_object_put_ref(connection);
264}
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