libsigrokdecode  0.5.1
sigrok protocol decoding library
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session.c
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1 /*
2  * This file is part of the libsigrokdecode project.
3  *
4  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
5  * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
6  *
7  * This program is free software: you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation, either version 3 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program. If not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include <config.h>
22 #include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
23 #include "libsigrokdecode.h"
24 #include <inttypes.h>
25 #include <glib.h>
26 
27 /**
28  * @file
29  *
30  * Session handling.
31  */
32 
33 /**
34  * @defgroup grp_session Session handling
35  *
36  * Starting and handling decoding sessions.
37  *
38  * @{
39  */
40 
41 /** @cond PRIVATE */
42 
43 SRD_PRIV GSList *sessions = NULL;
44 SRD_PRIV int max_session_id = -1;
45 
46 /** @endcond */
47 
48 /** @private */
49 SRD_PRIV int session_is_valid(struct srd_session *sess)
50 {
51 
52  if (!sess || sess->session_id < 1)
53  return SRD_ERR;
54 
55  return SRD_OK;
56 }
57 
58 /**
59  * Create a decoding session.
60  *
61  * A session holds all decoder instances, their stack relationships and
62  * output callbacks.
63  *
64  * @param sess A pointer which will hold a pointer to a newly
65  * initialized session on return.
66  *
67  * @return SRD_OK upon success, a (negative) error code otherwise.
68  *
69  * @since 0.3.0
70  */
71 SRD_API int srd_session_new(struct srd_session **sess)
72 {
73 
74  if (!sess) {
75  srd_err("Invalid session pointer.");
76  return SRD_ERR_ARG;
77  }
78 
79  *sess = g_malloc(sizeof(struct srd_session));
80  (*sess)->session_id = ++max_session_id;
81  (*sess)->di_list = (*sess)->callbacks = NULL;
82 
83  /* Keep a list of all sessions, so we can clean up as needed. */
84  sessions = g_slist_append(sessions, *sess);
85 
86  srd_dbg("Created session %d.", (*sess)->session_id);
87 
88  return SRD_OK;
89 }
90 
91 /**
92  * Start a decoding session.
93  *
94  * Decoders, instances and stack must have been prepared beforehand,
95  * and all SRD_CONF parameters set.
96  *
97  * @param sess The session to start.
98  *
99  * @return SRD_OK upon success, a (negative) error code otherwise.
100  *
101  * @since 0.3.0
102  */
103 SRD_API int srd_session_start(struct srd_session *sess)
104 {
105  GSList *d;
106  struct srd_decoder_inst *di;
107  int ret;
108 
109  if (session_is_valid(sess) != SRD_OK) {
110  srd_err("Invalid session pointer.");
111  return SRD_ERR;
112  }
113 
114  srd_dbg("Calling start() on all instances in session %d.", sess->session_id);
115 
116  /* Run the start() method on all decoders receiving frontend data. */
117  ret = SRD_OK;
118  for (d = sess->di_list; d; d = d->next) {
119  di = d->data;
120  if ((ret = srd_inst_start(di)) != SRD_OK)
121  break;
122  }
123 
124  return ret;
125 }
126 
127 static int srd_inst_send_meta(struct srd_decoder_inst *di, int key,
128  GVariant *data)
129 {
130  PyObject *py_ret;
131  GSList *l;
132  struct srd_decoder_inst *next_di;
133  int ret;
134  PyGILState_STATE gstate;
135 
136  if (key != SRD_CONF_SAMPLERATE)
137  /* This is the only key we pass on to the decoder for now. */
138  return SRD_OK;
139 
140  gstate = PyGILState_Ensure();
141 
142  if (PyObject_HasAttrString(di->py_inst, "metadata")) {
143  py_ret = PyObject_CallMethod(di->py_inst, "metadata", "lK",
144  (long)SRD_CONF_SAMPLERATE,
145  (unsigned long long)g_variant_get_uint64(data));
146  Py_XDECREF(py_ret);
147  }
148 
149  PyGILState_Release(gstate);
150 
151  /* Push metadata to all the PDs stacked on top of this one. */
152  for (l = di->next_di; l; l = l->next) {
153  next_di = l->data;
154  if ((ret = srd_inst_send_meta(next_di, key, data)) != SRD_OK)
155  return ret;
156  }
157 
158  return SRD_OK;
159 }
160 
161 /**
162  * Set a metadata configuration key in a session.
163  *
164  * @param sess The session to configure.
165  * @param key The configuration key (SRD_CONF_*).
166  * @param data The new value for the key, as a GVariant with GVariantType
167  * appropriate to that key. A floating reference can be passed
168  * in; its refcount will be sunk and unreferenced after use.
169  *
170  * @return SRD_OK upon success, a (negative) error code otherwise.
171  *
172  * @since 0.3.0
173  */
174 SRD_API int srd_session_metadata_set(struct srd_session *sess, int key,
175  GVariant *data)
176 {
177  GSList *l;
178  int ret;
179 
180  if (session_is_valid(sess) != SRD_OK) {
181  srd_err("Invalid session.");
182  return SRD_ERR_ARG;
183  }
184 
185  if (!key) {
186  srd_err("Invalid key.");
187  return SRD_ERR_ARG;
188  }
189 
190  if (!data) {
191  srd_err("Invalid value.");
192  return SRD_ERR_ARG;
193  }
194 
195  /* Hardcoded to samplerate/uint64 for now. */
196 
197  if (key != SRD_CONF_SAMPLERATE) {
198  srd_err("Unknown config key %d.", key);
199  return SRD_ERR_ARG;
200  }
201  if (!g_variant_is_of_type(data, G_VARIANT_TYPE_UINT64)) {
202  srd_err("Invalid value type: expected uint64, got %s",
203  g_variant_get_type_string(data));
204  return SRD_ERR_ARG;
205  }
206 
207  srd_dbg("Setting session %d samplerate to %"G_GUINT64_FORMAT".",
208  sess->session_id, g_variant_get_uint64(data));
209 
210  ret = SRD_OK;
211  for (l = sess->di_list; l; l = l->next) {
212  if ((ret = srd_inst_send_meta(l->data, key, data)) != SRD_OK)
213  break;
214  }
215 
216  g_variant_unref(data);
217 
218  return ret;
219 }
220 
221 /**
222  * Send a chunk of logic sample data to a running decoder session.
223  *
224  * If no channel map has been set up, the logic samples must be arranged
225  * in channel order, in the least amount of space possible. The default
226  * channel set consists of all required channels + all optional channels.
227  *
228  * The size of a sample in inbuf is 'unitsize' bytes. If no channel map
229  * has been configured, it is the minimum number of bytes needed to store
230  * the default channels.
231  *
232  * The calls to this function must provide the samples that shall be
233  * used by the protocol decoder
234  * - in the correct order ([...]5, 6, 4, 7, 8[...] is a bug),
235  * - starting from sample zero (2, 3, 4, 5, 6[...] is a bug),
236  * - consecutively, with no gaps (0, 1, 2, 4, 5[...] is a bug).
237  *
238  * The start- and end-sample numbers are absolute sample numbers (relative
239  * to the start of the whole capture/file/stream), i.e. they are not relative
240  * sample numbers within the chunk specified by 'inbuf' and 'inbuflen'.
241  *
242  * Correct example (4096 samples total, 4 chunks @ 1024 samples each):
243  * srd_session_send(s, 0, 1023, inbuf, 1024, 1);
244  * srd_session_send(s, 1024, 2047, inbuf, 1024, 1);
245  * srd_session_send(s, 2048, 3071, inbuf, 1024, 1);
246  * srd_session_send(s, 3072, 4095, inbuf, 1024, 1);
247  *
248  * The chunk size ('inbuflen') can be arbitrary and can differ between calls.
249  *
250  * Correct example (4096 samples total, 7 chunks @ various samples each):
251  * srd_session_send(s, 0, 1023, inbuf, 1024, 1);
252  * srd_session_send(s, 1024, 1123, inbuf, 100, 1);
253  * srd_session_send(s, 1124, 1423, inbuf, 300, 1);
254  * srd_session_send(s, 1424, 1642, inbuf, 219, 1);
255  * srd_session_send(s, 1643, 2047, inbuf, 405, 1);
256  * srd_session_send(s, 2048, 3071, inbuf, 1024, 1);
257  * srd_session_send(s, 3072, 4095, inbuf, 1024, 1);
258  *
259  * INCORRECT example (4096 samples total, 4 chunks @ 1024 samples each, but
260  * the start- and end-samplenumbers are not absolute):
261  * srd_session_send(s, 0, 1023, inbuf, 1024, 1);
262  * srd_session_send(s, 0, 1023, inbuf, 1024, 1);
263  * srd_session_send(s, 0, 1023, inbuf, 1024, 1);
264  * srd_session_send(s, 0, 1023, inbuf, 1024, 1);
265  *
266  * @param sess The session to use. Must not be NULL.
267  * @param abs_start_samplenum The absolute starting sample number for the
268  * buffer's sample set, relative to the start of capture.
269  * @param abs_end_samplenum The absolute ending sample number for the
270  * buffer's sample set, relative to the start of capture.
271  * @param inbuf Pointer to sample data. Must not be NULL.
272  * @param inbuflen Length in bytes of the buffer. Must be > 0.
273  * @param unitsize The number of bytes per sample. Must be > 0.
274  *
275  * @return SRD_OK upon success, a (negative) error code otherwise.
276  *
277  * @since 0.4.0
278  */
279 SRD_API int srd_session_send(struct srd_session *sess,
280  uint64_t abs_start_samplenum, uint64_t abs_end_samplenum,
281  const uint8_t *inbuf, uint64_t inbuflen, uint64_t unitsize)
282 {
283  GSList *d;
284  int ret;
285 
286  if (session_is_valid(sess) != SRD_OK) {
287  srd_err("Invalid session.");
288  return SRD_ERR_ARG;
289  }
290 
291  for (d = sess->di_list; d; d = d->next) {
292  if ((ret = srd_inst_decode(d->data, abs_start_samplenum,
293  abs_end_samplenum, inbuf, inbuflen, unitsize)) != SRD_OK)
294  return ret;
295  }
296 
297  return SRD_OK;
298 }
299 
300 /**
301  * Terminate currently executing decoders in a session, reset internal state.
302  *
303  * All decoder instances have their .wait() method terminated, which
304  * shall terminate .decode() as well. Afterwards the decoders' optional
305  * .reset() method gets executed.
306  *
307  * This routine allows callers to abort pending expensive operations,
308  * when they are no longer interested in the decoders' results. Note
309  * that the decoder state is lost and aborted work cannot resume.
310  *
311  * This routine also allows callers to re-use previously created decoder
312  * stacks to process new input data which is not related to previously
313  * processed input data. This avoids the necessity to re-construct the
314  * decoder stack.
315  *
316  * @param sess The session in which to terminate decoders.
317  * @return SRD_OK upon success, a (negative) error code otherwise.
318  *
319  * @since 0.5.1
320  */
321 SRD_API int srd_session_terminate_reset(struct srd_session *sess)
322 {
323  GSList *d;
324  int ret;
325 
326  if (session_is_valid(sess) != SRD_OK) {
327  srd_err("Invalid session.");
328  return SRD_ERR_ARG;
329  }
330 
331  for (d = sess->di_list; d; d = d->next) {
332  ret = srd_inst_terminate_reset(d->data);
333  if (ret != SRD_OK)
334  return ret;
335  }
336  return SRD_OK;
337 }
338 
339 /**
340  * Destroy a decoding session.
341  *
342  * All decoder instances and output callbacks are properly released.
343  *
344  * @param sess The session to be destroyed.
345  *
346  * @return SRD_OK upon success, a (negative) error code otherwise.
347  *
348  * @since 0.3.0
349  */
350 SRD_API int srd_session_destroy(struct srd_session *sess)
351 {
352  int session_id;
353 
354  if (!sess) {
355  srd_err("Invalid session.");
356  return SRD_ERR_ARG;
357  }
358 
359  session_id = sess->session_id;
360  if (sess->di_list)
361  srd_inst_free_all(sess);
362  if (sess->callbacks)
363  g_slist_free_full(sess->callbacks, g_free);
364  sessions = g_slist_remove(sessions, sess);
365  g_free(sess);
366 
367  srd_dbg("Destroyed session %d.", session_id);
368 
369  return SRD_OK;
370 }
371 
372 /**
373  * Register/add a decoder output callback function.
374  *
375  * The function will be called when a protocol decoder sends output back
376  * to the PD controller (except for Python objects, which only go up the
377  * stack).
378  *
379  * @param sess The output session in which to register the callback.
380  * @param output_type The output type this callback will receive. Only one
381  * callback per output type can be registered.
382  * @param cb The function to call. Must not be NULL.
383  * @param cb_data Private data for the callback function. Can be NULL.
384  *
385  * @since 0.3.0
386  */
387 SRD_API int srd_pd_output_callback_add(struct srd_session *sess,
388  int output_type, srd_pd_output_callback cb, void *cb_data)
389 {
390  struct srd_pd_callback *pd_cb;
391 
392  if (session_is_valid(sess) != SRD_OK) {
393  srd_err("Invalid session.");
394  return SRD_ERR_ARG;
395  }
396 
397  srd_dbg("Registering new callback for output type %d.", output_type);
398 
399  pd_cb = g_malloc(sizeof(struct srd_pd_callback));
400  pd_cb->output_type = output_type;
401  pd_cb->cb = cb;
402  pd_cb->cb_data = cb_data;
403  sess->callbacks = g_slist_append(sess->callbacks, pd_cb);
404 
405  return SRD_OK;
406 }
407 
408 /** @private */
409 SRD_PRIV struct srd_pd_callback *srd_pd_output_callback_find(
410  struct srd_session *sess, int output_type)
411 {
412  GSList *l;
413  struct srd_pd_callback *tmp, *pd_cb;
414 
415  if (session_is_valid(sess) != SRD_OK) {
416  srd_err("Invalid session.");
417  return NULL;
418  }
419 
420  pd_cb = NULL;
421  for (l = sess->callbacks; l; l = l->next) {
422  tmp = l->data;
423  if (tmp->output_type == output_type) {
424  pd_cb = tmp;
425  break;
426  }
427  }
428 
429  return pd_cb;
430 }
431 
432 /** @} */
void(* srd_pd_output_callback)(struct srd_proto_data *pdata, void *cb_data)
int srd_session_terminate_reset(struct srd_session *sess)
Terminate currently executing decoders in a session, reset internal state.
Definition: session.c:321
int srd_session_send(struct srd_session *sess, uint64_t abs_start_samplenum, uint64_t abs_end_samplenum, const uint8_t *inbuf, uint64_t inbuflen, uint64_t unitsize)
Send a chunk of logic sample data to a running decoder session.
Definition: session.c:279
int srd_session_destroy(struct srd_session *sess)
Destroy a decoding session.
Definition: session.c:350
const uint8_t * inbuf
Pointer to the buffer/chunk of input samples.
uint64_t inbuflen
Length (in bytes) of the input sample buffer.
#define SRD_API
int srd_session_new(struct srd_session **sess)
Create a decoding session.
Definition: session.c:71
No error.
The public libsigrokdecode header file to be used by frontends.
Function argument error.
srd_pd_output_callback cb
uint64_t abs_end_samplenum
Absolute end sample number.
int srd_pd_output_callback_add(struct srd_session *sess, int output_type, srd_pd_output_callback cb, void *cb_data)
Register/add a decoder output callback function.
Definition: session.c:387
#define SRD_PRIV
uint64_t abs_start_samplenum
Absolute start sample number.
int srd_session_metadata_set(struct srd_session *sess, int key, GVariant *data)
Set a metadata configuration key in a session.
Definition: session.c:174
int srd_session_start(struct srd_session *sess)
Start a decoding session.
Definition: session.c:103
Generic/unspecified error.
struct srd_session * sess