2 * SPDX-License-Identifier: MIT
4 * Copyright (c) 2015-2016 EfficiOS Inc. and Linux Foundation
5 * Copyright (c) 2015-2016 Philippe Proulx <pproulx@efficios.com>
7 * Babeltrace - CTF message iterator
10 #ifndef CTF_MSG_ITER_H
11 #define CTF_MSG_ITER_H
17 #include <babeltrace2/babeltrace.h>
18 #include "common/macros.h"
20 #include "../metadata/ctf-meta.hpp"
23 * @file ctf-msg-iter.h
25 * CTF message iterator
27 * This is a common internal API used by CTF source plugins. It allows
28 * one to get messages from a user-provided medium.
32 * Medium operations status codes. These use the same values as
35 enum ctf_msg_iter_medium_status {
39 * The medium function called by the message iterator
40 * function reached the end of the file.
42 CTF_MSG_ITER_MEDIUM_STATUS_EOF = 1,
45 * There is no data available right now, try again later.
47 CTF_MSG_ITER_MEDIUM_STATUS_AGAIN = 11,
50 CTF_MSG_ITER_MEDIUM_STATUS_ERROR = -1,
53 CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR = -12,
55 /** Everything okay. */
56 CTF_MSG_ITER_MEDIUM_STATUS_OK = 0,
60 * CTF message iterator API status code.
62 enum ctf_msg_iter_status {
66 * The medium function called by the message iterator
67 * function reached the end of the file.
69 CTF_MSG_ITER_STATUS_EOF = CTF_MSG_ITER_MEDIUM_STATUS_EOF,
72 * There is no data available right now, try again later.
74 * Some condition resulted in the
75 * ctf_msg_iter_medium_ops::request_bytes() user function not
76 * having access to any data now. You should retry calling the
77 * last called message iterator function once the situation
80 CTF_MSG_ITER_STATUS_AGAIN = CTF_MSG_ITER_MEDIUM_STATUS_AGAIN,
83 CTF_MSG_ITER_STATUS_ERROR = CTF_MSG_ITER_MEDIUM_STATUS_ERROR,
86 CTF_MSG_ITER_STATUS_MEMORY_ERROR = CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR,
88 /** Everything okay. */
89 CTF_MSG_ITER_STATUS_OK = CTF_MSG_ITER_MEDIUM_STATUS_OK,
95 * Those user functions are called by the message iterator
96 * functions to request medium actions.
98 struct ctf_msg_iter_medium_ops {
100 * Returns the next byte buffer to be used by the binary file
101 * reader to deserialize binary data.
103 * This function \em must be defined.
105 * The purpose of this function is to return a buffer of bytes
106 * to the message iterator, of a maximum of \p request_sz
107 * bytes. If this function cannot return a buffer of at least
108 * \p request_sz bytes, it may return a smaller buffer. In
109 * either cases, \p buffer_sz must be set to the returned buffer
112 * The returned buffer's ownership remains the medium, in that
113 * it won't be freed by the message iterator functions. The
114 * returned buffer won't be modified by the message
115 * iterator functions either.
117 * When this function is called for the first time for a given
118 * file, the offset within the file is considered to be 0. The
119 * next times this function is called, the returned buffer's
120 * byte offset within the complete file must be the previous
121 * offset plus the last returned value of \p buffer_sz by this
124 * This function must return one of the following statuses:
126 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
127 * is okay, i.e. \p buffer_sz is set to a positive value
128 * reflecting the number of available bytes in the buffer
129 * starting at the address written in \p buffer_addr.
130 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
131 * available right now. In this case, the message
132 * iterator function called by the user returns
133 * #CTF_MSG_ITER_STATUS_AGAIN, and it is the user's
134 * responsibility to make sure enough data becomes available
135 * before calling the \em same message iterator
136 * function again to continue the decoding process.
137 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
138 * the file was reached, and no more data will ever be
139 * available for this file. In this case, the message
140 * iterator function called by the user returns
141 * #CTF_MSG_ITER_STATUS_EOF. This must \em not be
142 * returned when returning at least one byte of data to the
143 * caller, i.e. this must be returned when there's
144 * absolutely nothing left; should the request size be
145 * larger than what's left in the file, this function must
146 * return what's left, setting \p buffer_sz to the number of
147 * remaining bytes, and return
148 * #CTF_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
150 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
151 * error occurred during this operation. In this case, the
152 * message iterator function called by the user returns
153 * #CTF_MSG_ITER_STATUS_ERROR.
155 * If #CTF_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
156 * values of \p buffer_sz and \p buffer_addr are \em ignored by
159 * @param request_sz Requested buffer size (bytes)
160 * @param buffer_addr Returned buffer address
161 * @param buffer_sz Returned buffer's size (bytes)
162 * @param data User data
163 * @returns Status code (see description above)
165 enum ctf_msg_iter_medium_status (* request_bytes)(size_t request_sz,
166 uint8_t **buffer_addr, size_t *buffer_sz, void *data);
169 * Repositions the underlying stream's position.
171 * This *optional* method repositions the underlying stream
172 * to a given absolute position in the medium.
174 * @param offset Offset to use for the given directive
175 * @param data User data
176 * @returns One of #ctf_msg_iter_medium_status values
178 enum ctf_msg_iter_medium_status (* seek)(off_t offset, void *data);
181 * Called when the message iterator wishes to inform the medium that it
182 * is about to start a new packet.
184 * After the iterator has called switch_packet, the following call to
185 * request_bytes must return the content at the start of the next
187 enum ctf_msg_iter_medium_status (* switch_packet)(void *data);
190 * Returns a stream instance (weak reference) for the given
193 * This is called after a packet header is read, and the
194 * corresponding stream class is found by the message
197 * @param stream_class Stream class of the stream to get
198 * @param stream_id Stream (instance) ID of the stream
199 * to get (-1ULL if not available)
200 * @param data User data
201 * @returns Stream instance (weak reference) or
204 bt_stream * (* borrow_stream)(bt_stream_class *stream_class,
205 int64_t stream_id, void *data);
208 /** CTF message iterator. */
212 * Creates a CTF message iterator.
214 * Upon successful completion, the reference count of \p trace is
217 * @param trace Trace to read
218 * @param max_request_sz Maximum buffer size, in bytes, to
220 * ctf_msg_iter_medium_ops::request_bytes()
222 * @param medops Medium operations
223 * @param medops_data User data (passed to medium operations)
224 * @returns New CTF message iterator on
225 * success, or \c NULL on error
228 struct ctf_msg_iter *ctf_msg_iter_create(
229 struct ctf_trace_class *tc,
230 size_t max_request_sz,
231 struct ctf_msg_iter_medium_ops medops,
233 bt_logging_level log_level,
234 bt_self_component *self_comp,
235 bt_self_message_iterator *self_msg_iter);
238 * Destroys a CTF message iterator, freeing all internal resources.
240 * The registered trace's reference count is decremented.
242 * @param msg_iter CTF message iterator
245 void ctf_msg_iter_destroy(struct ctf_msg_iter *msg_iter);
248 * Returns the next message from a CTF message iterator.
250 * Upon successful completion, #CTF_MSG_ITER_STATUS_OK is
251 * returned, and the next message is written to \p msg.
252 * In this case, the caller is responsible for calling
253 * bt_message_put() on the returned message.
255 * If this function returns #CTF_MSG_ITER_STATUS_AGAIN, the caller
256 * should make sure that data becomes available to its medium, and
257 * call this function again, until another status is returned.
259 * @param msg_iter CTF message iterator
260 * @param message Returned message if the function's
261 * return value is #CTF_MSG_ITER_STATUS_OK
262 * @returns One of #ctf_msg_iter_status values
265 enum ctf_msg_iter_status ctf_msg_iter_get_next_message(
266 struct ctf_msg_iter *msg_it,
267 const bt_message **message);
269 struct ctf_msg_iter_packet_properties {
270 int64_t exp_packet_total_size;
271 int64_t exp_packet_content_size;
272 uint64_t stream_class_id;
273 int64_t data_stream_id;
276 uint64_t discarded_events;
278 uint64_t beginning_clock;
284 enum ctf_msg_iter_status ctf_msg_iter_get_packet_properties(
285 struct ctf_msg_iter *msg_it,
286 struct ctf_msg_iter_packet_properties *props);
289 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_first_event_clock_snapshot(
290 struct ctf_msg_iter *msg_it, uint64_t *first_event_cs);
293 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_last_event_clock_snapshot(
294 struct ctf_msg_iter *msg_it, uint64_t *last_event_cs);
297 enum ctf_msg_iter_status ctf_msg_iter_seek(
298 struct ctf_msg_iter *msg_it, off_t offset);
301 * Resets the iterator so that the next requested medium bytes are
302 * assumed to be the first bytes of a new stream. Depending on
303 * ctf_msg_iter_set_emit_stream_beginning_message(), the first message
304 * which this iterator emits after calling ctf_msg_iter_reset() is of
305 * type `CTF_MESSAGE_TYPE_STREAM_BEGINNING`.
308 void ctf_msg_iter_reset(struct ctf_msg_iter *msg_it);
311 * Like ctf_msg_iter_reset(), but preserves stream-dependent state.
314 void ctf_msg_iter_reset_for_next_stream_file(struct ctf_msg_iter *msg_it);
317 void ctf_msg_iter_set_dry_run(struct ctf_msg_iter *msg_it,
321 const char *ctf_msg_iter_medium_status_string(
322 enum ctf_msg_iter_medium_status status)
325 case CTF_MSG_ITER_MEDIUM_STATUS_EOF:
327 case CTF_MSG_ITER_MEDIUM_STATUS_AGAIN:
329 case CTF_MSG_ITER_MEDIUM_STATUS_ERROR:
331 case CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR:
332 return "MEMORY_ERROR";
333 case CTF_MSG_ITER_MEDIUM_STATUS_OK:
341 const char *ctf_msg_iter_status_string(
342 enum ctf_msg_iter_status status)
345 case CTF_MSG_ITER_STATUS_EOF:
347 case CTF_MSG_ITER_STATUS_AGAIN:
349 case CTF_MSG_ITER_STATUS_ERROR:
351 case CTF_MSG_ITER_STATUS_MEMORY_ERROR:
352 return "MEMORY_ERROR";
353 case CTF_MSG_ITER_STATUS_OK:
360 #endif /* CTF_MSG_ITER_H */