| 1 | #include <stdlib.h> |
| 2 | #include <stdio.h> |
| 3 | #include <stdint.h> |
| 4 | #include <inttypes.h> |
| 5 | #include <string.h> |
| 6 | #include <stdbool.h> |
| 7 | #include <babeltrace2/babeltrace.h> |
| 8 | |
| 9 | /* Filter component's private data */ |
| 10 | struct distill { |
| 11 | /* Names of the classes of the events to discard (owned by this) */ |
| 12 | const bt_value *names_value; |
| 13 | |
| 14 | /* Component's input port (weak) */ |
| 15 | bt_self_component_port_input *in_port; |
| 16 | }; |
| 17 | |
| 18 | /* |
| 19 | * Initializes the filter component. |
| 20 | */ |
| 21 | static |
| 22 | bt_component_class_initialize_method_status distill_initialize( |
| 23 | bt_self_component_filter *self_component_filter, |
| 24 | bt_self_component_filter_configuration *configuration, |
| 25 | const bt_value *params, void *initialize_method_data) |
| 26 | { |
| 27 | /* Allocate a private data structure */ |
| 28 | struct distill *distill = malloc(sizeof(*distill)); |
| 29 | |
| 30 | /* |
| 31 | * Keep a reference of the `names` array value parameter so that the |
| 32 | * "next" method of a message iterator can access it to decide |
| 33 | * whether or not to discard an event message. |
| 34 | */ |
| 35 | distill->names_value = |
| 36 | bt_value_map_borrow_entry_value_const(params, "names"); |
| 37 | bt_value_get_ref(distill->names_value); |
| 38 | |
| 39 | /* Set the component's user data to our private data structure */ |
| 40 | bt_self_component_set_data( |
| 41 | bt_self_component_filter_as_self_component(self_component_filter), |
| 42 | distill); |
| 43 | |
| 44 | /* |
| 45 | * Add an input port named `in` to the filter component. |
| 46 | * |
| 47 | * This is needed so that this filter component can be connected to |
| 48 | * a filter or a source component. With a connected upstream |
| 49 | * component, this filter component's message iterator can create a |
| 50 | * message iterator to consume messages. |
| 51 | * |
| 52 | * Add an output port named `out` to the filter component. |
| 53 | * |
| 54 | * This is needed so that this filter component can be connected to |
| 55 | * a filter or a sink component. Once a downstream component is |
| 56 | * connected, it can create our message iterator. |
| 57 | */ |
| 58 | bt_self_component_filter_add_input_port(self_component_filter, |
| 59 | "in", NULL, &distill->in_port); |
| 60 | bt_self_component_filter_add_output_port(self_component_filter, |
| 61 | "out", NULL, NULL); |
| 62 | |
| 63 | return BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK; |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * Finalizes the filter component. |
| 68 | */ |
| 69 | static |
| 70 | void distill_finalize(bt_self_component_filter *self_component_filter) |
| 71 | { |
| 72 | /* Retrieve our private data from the component's user data */ |
| 73 | struct distill *distill = bt_self_component_get_data( |
| 74 | bt_self_component_filter_as_self_component(self_component_filter)); |
| 75 | |
| 76 | /* Put all references */ |
| 77 | bt_value_put_ref(distill->names_value); |
| 78 | |
| 79 | /* Free the allocated structure */ |
| 80 | free(distill); |
| 81 | } |
| 82 | |
| 83 | /* Message iterator's private data */ |
| 84 | struct distill_message_iterator { |
| 85 | /* (Weak) link to the component's private data */ |
| 86 | struct distill *distill; |
| 87 | |
| 88 | /* Upstream message iterator (owned by this) */ |
| 89 | bt_message_iterator *message_iterator; |
| 90 | }; |
| 91 | |
| 92 | /* |
| 93 | * Initializes the message iterator. |
| 94 | */ |
| 95 | static |
| 96 | bt_message_iterator_class_initialize_method_status |
| 97 | distill_message_iterator_initialize( |
| 98 | bt_self_message_iterator *self_message_iterator, |
| 99 | bt_self_message_iterator_configuration *configuration, |
| 100 | bt_self_component_port_output *self_port) |
| 101 | { |
| 102 | /* Allocate a private data structure */ |
| 103 | struct distill_message_iterator *distill_iter = |
| 104 | malloc(sizeof(*distill_iter)); |
| 105 | |
| 106 | /* Retrieve the component's private data from its user data */ |
| 107 | struct distill *distill = bt_self_component_get_data( |
| 108 | bt_self_message_iterator_borrow_component(self_message_iterator)); |
| 109 | |
| 110 | /* Keep a link to the component's private data */ |
| 111 | distill_iter->distill = distill; |
| 112 | |
| 113 | /* Create the upstream message iterator */ |
| 114 | bt_message_iterator_create_from_message_iterator(self_message_iterator, |
| 115 | distill->in_port, &distill_iter->message_iterator); |
| 116 | |
| 117 | /* Set the message iterator's user data to our private data structure */ |
| 118 | bt_self_message_iterator_set_data(self_message_iterator, distill_iter); |
| 119 | |
| 120 | return BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_OK; |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * Finalizes the message iterator. |
| 125 | */ |
| 126 | static |
| 127 | void distill_message_iterator_finalize( |
| 128 | bt_self_message_iterator *self_message_iterator) |
| 129 | { |
| 130 | /* Retrieve our private data from the message iterator's user data */ |
| 131 | struct distill_message_iterator *distill_iter = |
| 132 | bt_self_message_iterator_get_data(self_message_iterator); |
| 133 | |
| 134 | /* Free the allocated structure */ |
| 135 | free(distill_iter); |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | * Returns `true` if `message` passes, that is, one of: |
| 140 | * |
| 141 | * * It's not an event message. |
| 142 | * * The event message does not need to be discarded based on its event |
| 143 | * class's name. |
| 144 | */ |
| 145 | static |
| 146 | bool message_passes(struct distill_message_iterator *distill_iter, |
| 147 | const bt_message *message) |
| 148 | { |
| 149 | bool passes = true; |
| 150 | |
| 151 | /* Move as is if it's not an event message */ |
| 152 | if (bt_message_get_type(message) != BT_MESSAGE_TYPE_EVENT) { |
| 153 | passes = false; |
| 154 | goto end; |
| 155 | } |
| 156 | |
| 157 | /* Borrow the event message's event and its class */ |
| 158 | const bt_event *event = |
| 159 | bt_message_event_borrow_event_const(message); |
| 160 | const bt_event_class *event_class = bt_event_borrow_class_const(event); |
| 161 | |
| 162 | /* Get the event class's name */ |
| 163 | const char *name = bt_event_class_get_name(event_class); |
| 164 | |
| 165 | for (uint64_t i = 0; i < bt_value_array_get_length( |
| 166 | distill_iter->distill->names_value); i++) { |
| 167 | const char *discard_name = bt_value_string_get( |
| 168 | bt_value_array_borrow_element_by_index_const( |
| 169 | distill_iter->distill->names_value, i)); |
| 170 | |
| 171 | if (strcmp(name, discard_name) == 0) { |
| 172 | passes = false; |
| 173 | goto end; |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | end: |
| 178 | return passes; |
| 179 | } |
| 180 | |
| 181 | /* |
| 182 | * Returns the next message to the message iterator's user. |
| 183 | * |
| 184 | * This method can fill the `messages` array with up to `capacity` |
| 185 | * messages. |
| 186 | * |
| 187 | * To keep this example simple, we put a single message into `messages` |
| 188 | * and set `*count` to 1 (if the message iterator is not ended). |
| 189 | */ |
| 190 | static |
| 191 | bt_message_iterator_class_next_method_status distill_message_iterator_next( |
| 192 | bt_self_message_iterator *self_message_iterator, |
| 193 | bt_message_array_const messages, uint64_t capacity, |
| 194 | uint64_t *count) |
| 195 | { |
| 196 | /* Retrieve our private data from the message iterator's user data */ |
| 197 | struct distill_message_iterator *distill_iter = |
| 198 | bt_self_message_iterator_get_data(self_message_iterator); |
| 199 | |
| 200 | /* Consume a batch of messages from the upstream message iterator */ |
| 201 | bt_message_array_const upstream_messages; |
| 202 | uint64_t upstream_message_count; |
| 203 | bt_message_iterator_next_status next_status; |
| 204 | |
| 205 | consume_upstream_messages: |
| 206 | next_status = bt_message_iterator_next(distill_iter->message_iterator, |
| 207 | &upstream_messages, &upstream_message_count); |
| 208 | |
| 209 | /* Initialize the return status to a success */ |
| 210 | bt_message_iterator_class_next_method_status status = |
| 211 | BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_OK; |
| 212 | |
| 213 | switch (next_status) { |
| 214 | case BT_MESSAGE_ITERATOR_NEXT_STATUS_END: |
| 215 | /* End of iteration: put the message iterator's reference */ |
| 216 | bt_message_iterator_put_ref(distill_iter->message_iterator); |
| 217 | status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_END; |
| 218 | goto end; |
| 219 | case BT_MESSAGE_ITERATOR_NEXT_STATUS_AGAIN: |
| 220 | status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_AGAIN; |
| 221 | goto end; |
| 222 | case BT_MESSAGE_ITERATOR_NEXT_STATUS_MEMORY_ERROR: |
| 223 | status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_MEMORY_ERROR; |
| 224 | goto end; |
| 225 | case BT_MESSAGE_ITERATOR_NEXT_STATUS_ERROR: |
| 226 | status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_ERROR; |
| 227 | goto end; |
| 228 | default: |
| 229 | break; |
| 230 | } |
| 231 | |
| 232 | /* Output message array index */ |
| 233 | uint64_t i = 0; |
| 234 | |
| 235 | /* For each consumed message */ |
| 236 | for (uint64_t upstream_i = 0; upstream_i < upstream_message_count; |
| 237 | upstream_i++) { |
| 238 | /* Current message */ |
| 239 | const bt_message *upstream_message = upstream_messages[upstream_i]; |
| 240 | |
| 241 | /* Check if the upstream message passes */ |
| 242 | if (message_passes(distill_iter, upstream_message)) { |
| 243 | /* Move upstream message to output message array */ |
| 244 | messages[i] = upstream_message; |
| 245 | i++; |
| 246 | continue; |
| 247 | } |
| 248 | |
| 249 | /* Discard upstream message: put its reference */ |
| 250 | bt_message_put_ref(upstream_message); |
| 251 | } |
| 252 | |
| 253 | if (i == 0) { |
| 254 | /* |
| 255 | * We discarded all the upstream messages: get a new batch of |
| 256 | * messages, because this method _cannot_ return |
| 257 | * `BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_OK` and put no |
| 258 | * messages into its output message array. |
| 259 | */ |
| 260 | goto consume_upstream_messages; |
| 261 | } |
| 262 | |
| 263 | *count = i; |
| 264 | |
| 265 | end: |
| 266 | return status; |
| 267 | } |
| 268 | |
| 269 | /* Mandatory */ |
| 270 | BT_PLUGIN_MODULE(); |
| 271 | |
| 272 | /* Define the `distill` plugin */ |
| 273 | BT_PLUGIN(distill); |
| 274 | |
| 275 | /* Define the `theone` filter component class */ |
| 276 | BT_PLUGIN_FILTER_COMPONENT_CLASS(theone, distill_message_iterator_next); |
| 277 | |
| 278 | /* Set some of the `theone` filter component class's optional methods */ |
| 279 | BT_PLUGIN_FILTER_COMPONENT_CLASS_INITIALIZE_METHOD(theone, distill_initialize); |
| 280 | BT_PLUGIN_FILTER_COMPONENT_CLASS_FINALIZE_METHOD(theone, distill_finalize); |
| 281 | BT_PLUGIN_FILTER_COMPONENT_CLASS_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD( |
| 282 | theone, distill_message_iterator_initialize); |
| 283 | BT_PLUGIN_FILTER_COMPONENT_CLASS_MESSAGE_ITERATOR_CLASS_FINALIZE_METHOD(theone, |
| 284 | distill_message_iterator_finalize); |