lib: prepare the ground for stateful query operations
[babeltrace.git] / src / lib / graph / query-executor.c
1 /*
2 * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 * SOFTWARE.
21 */
22
23 #define BT_LOG_TAG "LIB/QUERY-EXECUTOR"
24 #include "lib/logging.h"
25
26 #include "common/assert.h"
27 #include "common/common.h"
28 #include "lib/assert-pre.h"
29 #include "lib/assert-post.h"
30 #include <babeltrace2/graph/query-executor-const.h>
31 #include <babeltrace2/graph/query-executor.h>
32 #include <babeltrace2/graph/component-class.h>
33 #include <babeltrace2/value.h>
34 #include <babeltrace2/value-const.h>
35 #include "lib/object.h"
36 #include "compat/compiler.h"
37
38 #include "component-class.h"
39 #include "query-executor.h"
40 #include "interrupter.h"
41 #include "lib/func-status.h"
42
43 static
44 void bt_query_executor_destroy(struct bt_object *obj)
45 {
46 struct bt_query_executor *query_exec =
47 container_of(obj, struct bt_query_executor, base);
48
49 BT_LOGD("Destroying query executor: addr=%p", query_exec);
50
51 if (query_exec->interrupters) {
52 BT_LOGD_STR("Putting interrupters.");
53 g_ptr_array_free(query_exec->interrupters, TRUE);
54 query_exec->interrupters = NULL;
55 }
56
57 BT_LOGD_STR("Putting component class.");
58 BT_OBJECT_PUT_REF_AND_RESET(query_exec->comp_cls);
59
60 if (query_exec->object) {
61 g_string_free(query_exec->object, TRUE);
62 query_exec->object = NULL;
63 }
64
65 BT_LOGD_STR("Putting parameters.");
66 BT_OBJECT_PUT_REF_AND_RESET(query_exec->params);
67 BT_OBJECT_PUT_REF_AND_RESET(query_exec->default_interrupter);
68 g_free(query_exec);
69 }
70
71 struct bt_query_executor *bt_query_executor_create(
72 const bt_component_class *comp_cls, const char *object,
73 const bt_value *params)
74 {
75 struct bt_query_executor *query_exec;
76
77 BT_ASSERT_PRE_NON_NULL(comp_cls, "Component class");
78 BT_ASSERT_PRE_NON_NULL(object, "Object");
79 BT_LIB_LOGD("Creating query executor: "
80 "%![comp-cls-]+C, object=\"%s\", %![params-]%+v",
81 comp_cls, object, params);
82 query_exec = g_new0(struct bt_query_executor, 1);
83 if (!query_exec) {
84 BT_LIB_LOGE_APPEND_CAUSE(
85 "Failed to allocate one query executor.");
86 goto end;
87 }
88
89 query_exec->interrupters = g_ptr_array_new_with_free_func(
90 (GDestroyNotify) bt_object_put_no_null_check);
91 if (!query_exec->interrupters) {
92 BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate one GPtrArray.");
93 BT_OBJECT_PUT_REF_AND_RESET(query_exec);
94 goto end;
95 }
96
97 query_exec->default_interrupter = bt_interrupter_create();
98 if (!query_exec->default_interrupter) {
99 BT_LIB_LOGE_APPEND_CAUSE(
100 "Failed to create one interrupter object.");
101 BT_OBJECT_PUT_REF_AND_RESET(query_exec);
102 goto end;
103 }
104
105 query_exec->object = g_string_new(object);
106 if (!query_exec->object) {
107 BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate one GString.");
108 BT_OBJECT_PUT_REF_AND_RESET(query_exec);
109 goto end;
110 }
111
112 query_exec->comp_cls = comp_cls;
113 bt_object_get_no_null_check(query_exec->comp_cls);
114
115 if (!params) {
116 query_exec->params = bt_value_null;
117 } else {
118 query_exec->params = params;
119 }
120
121 bt_object_get_no_null_check(query_exec->params);
122 query_exec->log_level = BT_LOGGING_LEVEL_NONE;
123 bt_query_executor_add_interrupter(query_exec,
124 query_exec->default_interrupter);
125 bt_object_init_shared(&query_exec->base,
126 bt_query_executor_destroy);
127 BT_LIB_LOGD("Created query executor: "
128 "addr=%p, %![comp-cls-]+C, object=\"%s\", %![params-]%+v",
129 query_exec, comp_cls, object, params);
130
131 end:
132 return (void *) query_exec;
133 }
134
135 enum bt_query_executor_query_status bt_query_executor_query(
136 struct bt_query_executor *query_exec,
137 const struct bt_value **user_result)
138 {
139 typedef enum bt_component_class_query_method_status (*method_t)(
140 void * /* self component class */,
141 void * /* private query executor */,
142 const char * /* object */,
143 const struct bt_value * /* parameters */,
144 const struct bt_value ** /* result */);
145
146 enum bt_query_executor_query_status status;
147 enum bt_component_class_query_method_status query_status;
148 method_t method = NULL;
149
150 BT_ASSERT_PRE_NON_NULL(query_exec, "Query executor");
151 BT_ASSERT_PRE_NON_NULL(user_result, "Result (output)");
152
153 /*
154 * Initial check: is the query executor already interrupted? If
155 * so, return `BT_FUNC_STATUS_AGAIN`. Returning this status is
156 * harmless: it's not `BT_FUNC_STATUS_OK` (there's no result),
157 * and it's not `BT_FUNC_STATUS_ERROR` either (there's no
158 * legitimate error). Since any query operation could return
159 * `BT_FUNC_STATUS_AGAIN` when interrupted or instead of
160 * blocking, the caller is responsible for checking the
161 * interruption state of the query executor when getting this
162 * status.
163 */
164 if (bt_query_executor_is_interrupted(query_exec)) {
165 BT_LIB_LOGD("Query executor is interrupted: "
166 "not performing the query operation: "
167 "query-exec-addr=%p, %![cc-]+C, object=\"%s\", "
168 "%![params-]+v, log-level=%s",
169 query_exec, query_exec->comp_cls,
170 query_exec->object->str, query_exec->params,
171 bt_common_logging_level_string(query_exec->log_level));
172 status = BT_FUNC_STATUS_AGAIN;
173 goto end;
174 }
175
176 switch (query_exec->comp_cls->type) {
177 case BT_COMPONENT_CLASS_TYPE_SOURCE:
178 {
179 struct bt_component_class_source *src_cc = (void *)
180 query_exec->comp_cls;
181
182 method = (method_t) src_cc->methods.query;
183 break;
184 }
185 case BT_COMPONENT_CLASS_TYPE_FILTER:
186 {
187 struct bt_component_class_filter *flt_cc = (void *)
188 query_exec->comp_cls;
189
190 method = (method_t) flt_cc->methods.query;
191 break;
192 }
193 case BT_COMPONENT_CLASS_TYPE_SINK:
194 {
195 struct bt_component_class_sink *sink_cc = (void *)
196 query_exec->comp_cls;
197
198 method = (method_t) sink_cc->methods.query;
199 break;
200 }
201 default:
202 abort();
203 }
204
205 if (!method) {
206 /* Not an error: nothing to query */
207 BT_LIB_LOGD("Component class has no registered query method: "
208 "%!+C", query_exec->comp_cls);
209 status = BT_FUNC_STATUS_UNKNOWN_OBJECT;
210 goto end;
211 }
212
213 BT_LIB_LOGD("Calling user's query method: "
214 "query-exec-addr=%p, %![cc-]+C, object=\"%s\", %![params-]+v, "
215 "log-level=%s",
216 query_exec, query_exec->comp_cls, query_exec->object->str,
217 query_exec->params,
218 bt_common_logging_level_string(query_exec->log_level));
219 *user_result = NULL;
220 query_status = method((void *) query_exec->comp_cls,
221 (void *) query_exec, query_exec->object->str,
222 query_exec->params, user_result);
223 BT_LIB_LOGD("User method returned: status=%s, %![res-]+v",
224 bt_common_func_status_string(query_status), *user_result);
225 BT_ASSERT_POST(query_status != BT_FUNC_STATUS_OK || *user_result,
226 "User method returned `BT_FUNC_STATUS_OK` without a result.");
227 status = (int) query_status;
228
229 if (status < 0) {
230 BT_LIB_LOGW_APPEND_CAUSE(
231 "Component class's \"query\" method failed: "
232 "query-exec-addr=%p, %![cc-]+C, object=\"%s\", "
233 "%![params-]+v, log-level=%s", query_exec,
234 query_exec->comp_cls, query_exec->object->str,
235 query_exec->params,
236 bt_common_logging_level_string(query_exec->log_level));
237 goto end;
238 }
239
240 end:
241 return status;
242 }
243
244 enum bt_query_executor_add_interrupter_status bt_query_executor_add_interrupter(
245 struct bt_query_executor *query_exec,
246 const struct bt_interrupter *intr)
247 {
248 BT_ASSERT_PRE_NON_NULL(query_exec, "Query executor");
249 BT_ASSERT_PRE_NON_NULL(intr, "Interrupter");
250 g_ptr_array_add(query_exec->interrupters, (void *) intr);
251 bt_object_get_no_null_check(intr);
252 BT_LIB_LOGD("Added interrupter to query executor: "
253 "query-exec-addr=%p, %![intr-]+z",
254 query_exec, intr);
255 return BT_FUNC_STATUS_OK;
256 }
257
258 bt_bool bt_query_executor_is_interrupted(const struct bt_query_executor *query_exec)
259 {
260 BT_ASSERT_PRE_NON_NULL(query_exec, "Query executor");
261 return (bt_bool) bt_interrupter_array_any_is_set(
262 query_exec->interrupters);
263 }
264
265 void bt_query_executor_interrupt(struct bt_query_executor *query_exec)
266 {
267 BT_ASSERT_PRE_NON_NULL(query_exec, "Query executor");
268 bt_interrupter_set(query_exec->default_interrupter);
269 BT_LIB_LOGI("Interrupted query executor: query-exec-addr=%p",
270 query_exec);
271 }
272
273 enum bt_query_executor_set_logging_level_status
274 bt_query_executor_set_logging_level(struct bt_query_executor *query_exec,
275 enum bt_logging_level log_level)
276 {
277 BT_ASSERT_PRE_NON_NULL(query_exec, "Query executor");
278 query_exec->log_level = log_level;
279 return BT_FUNC_STATUS_OK;
280 }
281
282 enum bt_logging_level bt_query_executor_get_logging_level(
283 const struct bt_query_executor *query_exec)
284 {
285 BT_ASSERT_PRE_NON_NULL(query_exec, "Query executor");
286 return query_exec->log_level;
287 }
288
289 void bt_query_executor_get_ref(const struct bt_query_executor *query_executor)
290 {
291 bt_object_get_ref(query_executor);
292 }
293
294 void bt_query_executor_put_ref(const struct bt_query_executor *query_executor)
295 {
296 bt_object_put_ref(query_executor);
297 }
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