21b756ba370620bf99db2aefb8a31f0f7f9c6b10
[libsigrokdecode.git] / decoder.c
1 /*
2  * This file is part of the libsigrokdecode project.
3  *
4  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
5  * Copyright (C) 2012 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 <glib.h>
25
26 /**
27  * @file
28  *
29  * Listing, loading, unloading, and handling protocol decoders.
30  */
31
32 /**
33  * @defgroup grp_decoder Protocol decoders
34  *
35  * Handling protocol decoders.
36  *
37  * @{
38  */
39
40 /** @cond PRIVATE */
41
42 /* The list of loaded protocol decoders. */
43 static GSList *pd_list = NULL;
44
45 /* srd.c */
46 extern SRD_PRIV GSList *searchpaths;
47
48 /* session.c */
49 extern SRD_PRIV GSList *sessions;
50 extern SRD_PRIV int max_session_id;
51
52 /* module_sigrokdecode.c */
53 extern SRD_PRIV PyObject *mod_sigrokdecode;
54
55 /** @endcond */
56
57 static gboolean srd_check_init(void)
58 {
59         if (max_session_id < 0) {
60                 srd_err("Library is not initialized.");
61                 return FALSE;
62         } else
63                 return TRUE;
64 }
65
66 /**
67  * Returns the list of loaded protocol decoders.
68  *
69  * This is a GSList of pointers to struct srd_decoder items.
70  *
71  * @return List of decoders, NULL if none are supported or loaded.
72  *
73  * @since 0.2.0
74  */
75 SRD_API const GSList *srd_decoder_list(void)
76 {
77         return pd_list;
78 }
79
80 /**
81  * Get the decoder with the specified ID.
82  *
83  * @param id The ID string of the decoder to return.
84  *
85  * @return The decoder with the specified ID, or NULL if not found.
86  *
87  * @since 0.1.0
88  */
89 SRD_API struct srd_decoder *srd_decoder_get_by_id(const char *id)
90 {
91         GSList *l;
92         struct srd_decoder *dec;
93
94         for (l = pd_list; l; l = l->next) {
95                 dec = l->data;
96                 if (!strcmp(dec->id, id))
97                         return dec;
98         }
99
100         return NULL;
101 }
102
103 static void channel_free(void *data)
104 {
105         struct srd_channel *ch = data;
106
107         if (!ch)
108                 return;
109
110         g_free(ch->desc);
111         g_free(ch->name);
112         g_free(ch->id);
113         g_free(ch);
114 }
115
116 static void variant_free(void *data)
117 {
118         GVariant *var = data;
119
120         if (!var)
121                 return;
122
123         g_variant_unref(var);
124 }
125
126 static void annotation_row_free(void *data)
127 {
128         struct srd_decoder_annotation_row *row = data;
129
130         if (!row)
131                 return;
132
133         g_slist_free(row->ann_classes);
134         g_free(row->desc);
135         g_free(row->id);
136         g_free(row);
137 }
138
139 static void decoder_option_free(void *data)
140 {
141         struct srd_decoder_option *opt = data;
142
143         if (!opt)
144                 return;
145
146         g_slist_free_full(opt->values, &variant_free);
147         variant_free(opt->def);
148         g_free(opt->desc);
149         g_free(opt->id);
150         g_free(opt);
151 }
152
153 static void decoder_free(struct srd_decoder *dec)
154 {
155         PyGILState_STATE gstate;
156
157         if (!dec)
158                 return;
159
160         gstate = PyGILState_Ensure();
161         Py_XDECREF(dec->py_dec);
162         Py_XDECREF(dec->py_mod);
163         PyGILState_Release(gstate);
164
165         g_slist_free_full(dec->options, &decoder_option_free);
166         g_slist_free_full(dec->binary, (GDestroyNotify)&g_strfreev);
167         g_slist_free_full(dec->annotation_rows, &annotation_row_free);
168         g_slist_free_full(dec->annotations, (GDestroyNotify)&g_strfreev);
169         g_slist_free_full(dec->opt_channels, &channel_free);
170         g_slist_free_full(dec->channels, &channel_free);
171
172         g_slist_free_full(dec->outputs, g_free);
173         g_slist_free_full(dec->inputs, g_free);
174         g_free(dec->license);
175         g_free(dec->desc);
176         g_free(dec->longname);
177         g_free(dec->name);
178         g_free(dec->id);
179
180         g_free(dec);
181 }
182
183 static int get_channels(const struct srd_decoder *d, const char *attr,
184                 GSList **out_pdchl, int offset)
185 {
186         PyObject *py_channellist, *py_entry;
187         struct srd_channel *pdch;
188         GSList *pdchl;
189         ssize_t i;
190         PyGILState_STATE gstate;
191
192         gstate = PyGILState_Ensure();
193
194         if (!PyObject_HasAttrString(d->py_dec, attr)) {
195                 /* No channels of this type specified. */
196                 PyGILState_Release(gstate);
197                 return SRD_OK;
198         }
199
200         pdchl = NULL;
201
202         py_channellist = PyObject_GetAttrString(d->py_dec, attr);
203         if (!py_channellist)
204                 goto except_out;
205
206         if (!PyTuple_Check(py_channellist)) {
207                 srd_err("Protocol decoder %s %s attribute is not a tuple.",
208                         d->name, attr);
209                 goto err_out;
210         }
211
212         for (i = PyTuple_Size(py_channellist) - 1; i >= 0; i--) {
213                 py_entry = PyTuple_GetItem(py_channellist, i);
214                 if (!py_entry)
215                         goto except_out;
216
217                 if (!PyDict_Check(py_entry)) {
218                         srd_err("Protocol decoder %s %s attribute is not "
219                                 "a list of dict elements.", d->name, attr);
220                         goto err_out;
221                 }
222                 pdch = g_malloc(sizeof(struct srd_channel));
223                 /* Add to list right away so it doesn't get lost. */
224                 pdchl = g_slist_prepend(pdchl, pdch);
225
226                 if (py_dictitem_as_str(py_entry, "id", &pdch->id) != SRD_OK)
227                         goto err_out;
228                 if (py_dictitem_as_str(py_entry, "name", &pdch->name) != SRD_OK)
229                         goto err_out;
230                 if (py_dictitem_as_str(py_entry, "desc", &pdch->desc) != SRD_OK)
231                         goto err_out;
232
233                 pdch->order = offset + i;
234         }
235
236         Py_DECREF(py_channellist);
237         *out_pdchl = pdchl;
238
239         PyGILState_Release(gstate);
240
241         return SRD_OK;
242
243 except_out:
244         srd_exception_catch("Failed to get %s list of %s decoder",
245                         attr, d->name);
246 err_out:
247         g_slist_free_full(pdchl, &channel_free);
248         Py_XDECREF(py_channellist);
249         PyGILState_Release(gstate);
250
251         return SRD_ERR_PYTHON;
252 }
253
254 static int get_options(struct srd_decoder *d)
255 {
256         PyObject *py_opts, *py_opt, *py_str, *py_values, *py_default, *py_item;
257         GSList *options;
258         struct srd_decoder_option *o;
259         GVariant *gvar;
260         ssize_t opt, i;
261         PyGILState_STATE gstate;
262
263         gstate = PyGILState_Ensure();
264
265         if (!PyObject_HasAttrString(d->py_dec, "options")) {
266                 /* No options, that's fine. */
267                 PyGILState_Release(gstate);
268                 return SRD_OK;
269         }
270
271         options = NULL;
272
273         /* If present, options must be a tuple. */
274         py_opts = PyObject_GetAttrString(d->py_dec, "options");
275         if (!py_opts)
276                 goto except_out;
277
278         if (!PyTuple_Check(py_opts)) {
279                 srd_err("Protocol decoder %s: options attribute is not "
280                                 "a tuple.", d->id);
281                 goto err_out;
282         }
283
284         for (opt = PyTuple_Size(py_opts) - 1; opt >= 0; opt--) {
285                 py_opt = PyTuple_GetItem(py_opts, opt);
286                 if (!py_opt)
287                         goto except_out;
288
289                 if (!PyDict_Check(py_opt)) {
290                         srd_err("Protocol decoder %s options: each option "
291                                         "must consist of a dictionary.", d->name);
292                         goto err_out;
293                 }
294
295                 o = g_malloc0(sizeof(struct srd_decoder_option));
296                 /* Add to list right away so it doesn't get lost. */
297                 options = g_slist_prepend(options, o);
298
299                 py_str = PyDict_GetItemString(py_opt, "id");
300                 if (!py_str) {
301                         srd_err("Protocol decoder %s option %zd has no ID.",
302                                 d->name, opt);
303                         goto err_out;
304                 }
305                 if (py_str_as_str(py_str, &o->id) != SRD_OK)
306                         goto err_out;
307
308                 py_str = PyDict_GetItemString(py_opt, "desc");
309                 if (py_str) {
310                         if (py_str_as_str(py_str, &o->desc) != SRD_OK)
311                                 goto err_out;
312                 }
313
314                 py_default = PyDict_GetItemString(py_opt, "default");
315                 if (py_default) {
316                         gvar = py_obj_to_variant(py_default);
317                         if (!gvar) {
318                                 srd_err("Protocol decoder %s option 'default' has "
319                                         "invalid default value.", d->name);
320                                 goto err_out;
321                         }
322                         o->def = g_variant_ref_sink(gvar);
323                 }
324
325                 py_values = PyDict_GetItemString(py_opt, "values");
326                 if (py_values) {
327                         /* A default is required if a list of values is
328                          * given, since it's used to verify their type. */
329                         if (!o->def) {
330                                 srd_err("No default for option '%s'.", o->id);
331                                 goto err_out;
332                         }
333                         if (!PyTuple_Check(py_values)) {
334                                 srd_err("Option '%s' values should be a tuple.", o->id);
335                                 goto err_out;
336                         }
337
338                         for (i = PyTuple_Size(py_values) - 1; i >= 0; i--) {
339                                 py_item = PyTuple_GetItem(py_values, i);
340                                 if (!py_item)
341                                         goto except_out;
342
343                                 if (Py_TYPE(py_default) != Py_TYPE(py_item)) {
344                                         srd_err("All values for option '%s' must be "
345                                                 "of the same type as the default.",
346                                                 o->id);
347                                         goto err_out;
348                                 }
349                                 gvar = py_obj_to_variant(py_item);
350                                 if (!gvar) {
351                                         srd_err("Protocol decoder %s option 'values' "
352                                                 "contains invalid value.", d->name);
353                                         goto err_out;
354                                 }
355                                 o->values = g_slist_prepend(o->values,
356                                                 g_variant_ref_sink(gvar));
357                         }
358                 }
359         }
360         d->options = options;
361         Py_DECREF(py_opts);
362         PyGILState_Release(gstate);
363
364         return SRD_OK;
365
366 except_out:
367         srd_exception_catch("Failed to get %s decoder options", d->name);
368 err_out:
369         g_slist_free_full(options, &decoder_option_free);
370         Py_XDECREF(py_opts);
371         PyGILState_Release(gstate);
372
373         return SRD_ERR_PYTHON;
374 }
375
376 /* Convert annotation class attribute to GSList of char **.
377  */
378 static int get_annotations(struct srd_decoder *dec)
379 {
380         PyObject *py_annlist, *py_ann;
381         GSList *annotations;
382         char **annpair;
383         ssize_t i;
384         PyGILState_STATE gstate;
385
386         gstate = PyGILState_Ensure();
387
388         if (!PyObject_HasAttrString(dec->py_dec, "annotations")) {
389                 PyGILState_Release(gstate);
390                 return SRD_OK;
391         }
392
393         annotations = NULL;
394
395         py_annlist = PyObject_GetAttrString(dec->py_dec, "annotations");
396         if (!py_annlist)
397                 goto except_out;
398
399         if (!PyTuple_Check(py_annlist)) {
400                 srd_err("Protocol decoder %s annotations should "
401                         "be a tuple.", dec->name);
402                 goto err_out;
403         }
404
405         for (i = PyTuple_Size(py_annlist) - 1; i >= 0; i--) {
406                 py_ann = PyTuple_GetItem(py_annlist, i);
407                 if (!py_ann)
408                         goto except_out;
409
410                 if (!PyTuple_Check(py_ann) || PyTuple_Size(py_ann) != 2) {
411                         srd_err("Protocol decoder %s annotation %zd should "
412                                 "be a tuple with two elements.",
413                                 dec->name, i + 1);
414                         goto err_out;
415                 }
416                 if (py_strseq_to_char(py_ann, &annpair) != SRD_OK)
417                         goto err_out;
418
419                 annotations = g_slist_prepend(annotations, annpair);
420         }
421         dec->annotations = annotations;
422         Py_DECREF(py_annlist);
423         PyGILState_Release(gstate);
424
425         return SRD_OK;
426
427 except_out:
428         srd_exception_catch("Failed to get %s decoder annotations", dec->name);
429 err_out:
430         g_slist_free_full(annotations, (GDestroyNotify)&g_strfreev);
431         Py_XDECREF(py_annlist);
432         PyGILState_Release(gstate);
433
434         return SRD_ERR_PYTHON;
435 }
436
437 /* Convert annotation_rows to GSList of 'struct srd_decoder_annotation_row'.
438  */
439 static int get_annotation_rows(struct srd_decoder *dec)
440 {
441         PyObject *py_ann_rows, *py_ann_row, *py_ann_classes, *py_item;
442         GSList *annotation_rows;
443         struct srd_decoder_annotation_row *ann_row;
444         ssize_t i, k;
445         size_t class_idx;
446         PyGILState_STATE gstate;
447
448         gstate = PyGILState_Ensure();
449
450         if (!PyObject_HasAttrString(dec->py_dec, "annotation_rows")) {
451                 PyGILState_Release(gstate);
452                 return SRD_OK;
453         }
454
455         annotation_rows = NULL;
456
457         py_ann_rows = PyObject_GetAttrString(dec->py_dec, "annotation_rows");
458         if (!py_ann_rows)
459                 goto except_out;
460
461         if (!PyTuple_Check(py_ann_rows)) {
462                 srd_err("Protocol decoder %s annotation_rows "
463                         "must be a tuple.", dec->name);
464                 goto err_out;
465         }
466
467         for (i = PyTuple_Size(py_ann_rows) - 1; i >= 0; i--) {
468                 py_ann_row = PyTuple_GetItem(py_ann_rows, i);
469                 if (!py_ann_row)
470                         goto except_out;
471
472                 if (!PyTuple_Check(py_ann_row) || PyTuple_Size(py_ann_row) != 3) {
473                         srd_err("Protocol decoder %s annotation_rows "
474                                 "must contain only tuples of 3 elements.",
475                                 dec->name);
476                         goto err_out;
477                 }
478                 ann_row = g_malloc0(sizeof(struct srd_decoder_annotation_row));
479                 /* Add to list right away so it doesn't get lost. */
480                 annotation_rows = g_slist_prepend(annotation_rows, ann_row);
481
482                 py_item = PyTuple_GetItem(py_ann_row, 0);
483                 if (!py_item)
484                         goto except_out;
485                 if (py_str_as_str(py_item, &ann_row->id) != SRD_OK)
486                         goto err_out;
487
488                 py_item = PyTuple_GetItem(py_ann_row, 1);
489                 if (!py_item)
490                         goto except_out;
491                 if (py_str_as_str(py_item, &ann_row->desc) != SRD_OK)
492                         goto err_out;
493
494                 py_ann_classes = PyTuple_GetItem(py_ann_row, 2);
495                 if (!py_ann_classes)
496                         goto except_out;
497
498                 if (!PyTuple_Check(py_ann_classes)) {
499                         srd_err("Protocol decoder %s annotation_rows tuples "
500                                 "must have a tuple of numbers as 3rd element.",
501                                 dec->name);
502                         goto err_out;
503                 }
504
505                 for (k = PyTuple_Size(py_ann_classes) - 1; k >= 0; k--) {
506                         py_item = PyTuple_GetItem(py_ann_classes, k);
507                         if (!py_item)
508                                 goto except_out;
509
510                         if (!PyLong_Check(py_item)) {
511                                 srd_err("Protocol decoder %s annotation row "
512                                         "class tuple must only contain numbers.",
513                                         dec->name);
514                                 goto err_out;
515                         }
516                         class_idx = PyLong_AsSize_t(py_item);
517                         if (PyErr_Occurred())
518                                 goto except_out;
519
520                         ann_row->ann_classes = g_slist_prepend(ann_row->ann_classes,
521                                         GSIZE_TO_POINTER(class_idx));
522                 }
523         }
524         dec->annotation_rows = annotation_rows;
525         Py_DECREF(py_ann_rows);
526         PyGILState_Release(gstate);
527
528         return SRD_OK;
529
530 except_out:
531         srd_exception_catch("Failed to get %s decoder annotation rows",
532                         dec->name);
533 err_out:
534         g_slist_free_full(annotation_rows, &annotation_row_free);
535         Py_XDECREF(py_ann_rows);
536         PyGILState_Release(gstate);
537
538         return SRD_ERR_PYTHON;
539 }
540
541 /* Convert binary classes to GSList of char **.
542  */
543 static int get_binary_classes(struct srd_decoder *dec)
544 {
545         PyObject *py_bin_classes, *py_bin_class;
546         GSList *bin_classes;
547         char **bin;
548         ssize_t i;
549         PyGILState_STATE gstate;
550
551         gstate = PyGILState_Ensure();
552
553         if (!PyObject_HasAttrString(dec->py_dec, "binary")) {
554                 PyGILState_Release(gstate);
555                 return SRD_OK;
556         }
557
558         bin_classes = NULL;
559
560         py_bin_classes = PyObject_GetAttrString(dec->py_dec, "binary");
561         if (!py_bin_classes)
562                 goto except_out;
563
564         if (!PyTuple_Check(py_bin_classes)) {
565                 srd_err("Protocol decoder %s binary classes should "
566                         "be a tuple.", dec->name);
567                 goto err_out;
568         }
569
570         for (i = PyTuple_Size(py_bin_classes) - 1; i >= 0; i--) {
571                 py_bin_class = PyTuple_GetItem(py_bin_classes, i);
572                 if (!py_bin_class)
573                         goto except_out;
574
575                 if (!PyTuple_Check(py_bin_class)
576                                 || PyTuple_Size(py_bin_class) != 2) {
577                         srd_err("Protocol decoder %s binary classes should "
578                                 "consist only of tuples of 2 elements.",
579                                 dec->name);
580                         goto err_out;
581                 }
582                 if (py_strseq_to_char(py_bin_class, &bin) != SRD_OK)
583                         goto err_out;
584
585                 bin_classes = g_slist_prepend(bin_classes, bin);
586         }
587         dec->binary = bin_classes;
588         Py_DECREF(py_bin_classes);
589         PyGILState_Release(gstate);
590
591         return SRD_OK;
592
593 except_out:
594         srd_exception_catch("Failed to get %s decoder binary classes",
595                         dec->name);
596 err_out:
597         g_slist_free_full(bin_classes, (GDestroyNotify)&g_strfreev);
598         Py_XDECREF(py_bin_classes);
599         PyGILState_Release(gstate);
600
601         return SRD_ERR_PYTHON;
602 }
603
604 /* Check whether the Decoder class defines the named method.
605  */
606 static int check_method(PyObject *py_dec, const char *mod_name,
607                 const char *method_name)
608 {
609         PyObject *py_method;
610         int is_callable;
611         PyGILState_STATE gstate;
612
613         gstate = PyGILState_Ensure();
614
615         py_method = PyObject_GetAttrString(py_dec, method_name);
616         if (!py_method) {
617                 srd_exception_catch("Protocol decoder %s Decoder class "
618                                 "has no %s() method", mod_name, method_name);
619                 PyGILState_Release(gstate);
620                 return SRD_ERR_PYTHON;
621         }
622
623         is_callable = PyCallable_Check(py_method);
624         Py_DECREF(py_method);
625
626         PyGILState_Release(gstate);
627
628         if (!is_callable) {
629                 srd_err("Protocol decoder %s Decoder class attribute '%s' "
630                         "is not a method.", mod_name, method_name);
631                 return SRD_ERR_PYTHON;
632         }
633
634         return SRD_OK;
635 }
636
637 /**
638  * Get the API version of the specified decoder.
639  *
640  * @param d The decoder to use. Must not be NULL.
641  *
642  * @return The API version of the decoder, or 0 upon errors.
643  *
644  * @private
645  */
646 SRD_PRIV long srd_decoder_apiver(const struct srd_decoder *d)
647 {
648         PyObject *py_apiver;
649         long apiver;
650         PyGILState_STATE gstate;
651
652         if (!d)
653                 return 0;
654
655         gstate = PyGILState_Ensure();
656
657         py_apiver = PyObject_GetAttrString(d->py_dec, "api_version");
658         apiver = (py_apiver && PyLong_Check(py_apiver))
659                         ? PyLong_AsLong(py_apiver) : 0;
660         Py_XDECREF(py_apiver);
661
662         PyGILState_Release(gstate);
663
664         return apiver;
665 }
666
667 /**
668  * Load a protocol decoder module into the embedded Python interpreter.
669  *
670  * @param module_name The module name to be loaded.
671  *
672  * @return SRD_OK upon success, a (negative) error code otherwise.
673  *
674  * @since 0.1.0
675  */
676 SRD_API int srd_decoder_load(const char *module_name)
677 {
678         PyObject *py_basedec;
679         struct srd_decoder *d;
680         long apiver;
681         int is_subclass;
682         const char *fail_txt;
683         PyGILState_STATE gstate;
684
685         if (!srd_check_init())
686                 return SRD_ERR;
687
688         if (!module_name)
689                 return SRD_ERR_ARG;
690
691         gstate = PyGILState_Ensure();
692
693         if (PyDict_GetItemString(PyImport_GetModuleDict(), module_name)) {
694                 /* Module was already imported. */
695                 PyGILState_Release(gstate);
696                 return SRD_OK;
697         }
698
699         d = g_malloc0(sizeof(struct srd_decoder));
700         fail_txt = NULL;
701
702         d->py_mod = py_import_by_name(module_name);
703         if (!d->py_mod) {
704                 fail_txt = "import by name failed";
705                 goto except_out;
706         }
707
708         if (!mod_sigrokdecode) {
709                 srd_err("sigrokdecode module not loaded.");
710                 fail_txt = "sigrokdecode(3) not loaded";
711                 goto err_out;
712         }
713
714         /* Get the 'Decoder' class as Python object. */
715         d->py_dec = PyObject_GetAttrString(d->py_mod, "Decoder");
716         if (!d->py_dec) {
717                 fail_txt = "no 'Decoder' attribute in imported module";
718                 goto except_out;
719         }
720
721         py_basedec = PyObject_GetAttrString(mod_sigrokdecode, "Decoder");
722         if (!py_basedec) {
723                 fail_txt = "no 'Decoder' attribute in sigrokdecode(3)";
724                 goto except_out;
725         }
726
727         is_subclass = PyObject_IsSubclass(d->py_dec, py_basedec);
728         Py_DECREF(py_basedec);
729
730         if (!is_subclass) {
731                 srd_err("Decoder class in protocol decoder module %s is not "
732                         "a subclass of sigrokdecode.Decoder.", module_name);
733                 fail_txt = "not a subclass of sigrokdecode.Decoder";
734                 goto err_out;
735         }
736
737         /*
738          * Check that this decoder has the correct PD API version.
739          * PDs of different API versions are incompatible and cannot work.
740          */
741         apiver = srd_decoder_apiver(d);
742         if (apiver != 3) {
743                 srd_exception_catch("Only PD API version 3 is supported, "
744                         "decoder %s has version %ld", module_name, apiver);
745                 fail_txt = "API version mismatch";
746                 goto err_out;
747         }
748
749         /* Check Decoder class for required methods.
750          */
751         if (check_method(d->py_dec, module_name, "start") != SRD_OK) {
752                 fail_txt = "no 'start()' method";
753                 goto err_out;
754         }
755
756         if (check_method(d->py_dec, module_name, "decode") != SRD_OK) {
757                 fail_txt = "no 'decode()' method";
758                 goto err_out;
759         }
760
761         /* Store required fields in newly allocated strings. */
762         if (py_attr_as_str(d->py_dec, "id", &(d->id)) != SRD_OK) {
763                 fail_txt = "no 'id' attribute";
764                 goto err_out;
765         }
766
767         if (py_attr_as_str(d->py_dec, "name", &(d->name)) != SRD_OK) {
768                 fail_txt = "no 'name' attribute";
769                 goto err_out;
770         }
771
772         if (py_attr_as_str(d->py_dec, "longname", &(d->longname)) != SRD_OK) {
773                 fail_txt = "no 'longname' attribute";
774                 goto err_out;
775         }
776
777         if (py_attr_as_str(d->py_dec, "desc", &(d->desc)) != SRD_OK) {
778                 fail_txt = "no 'desc' attribute";
779                 goto err_out;
780         }
781
782         if (py_attr_as_str(d->py_dec, "license", &(d->license)) != SRD_OK) {
783                 fail_txt = "no 'license' attribute";
784                 goto err_out;
785         }
786
787         if (py_attr_as_strlist(d->py_dec, "inputs", &(d->inputs)) != SRD_OK) {
788                 fail_txt = "missing or malformed 'inputs' attribute";
789                 goto err_out;
790         }
791
792         if (py_attr_as_strlist(d->py_dec, "outputs", &(d->outputs)) != SRD_OK) {
793                 fail_txt = "missing or malformed 'outputs' attribute";
794                 goto err_out;
795         }
796
797         /* All options and their default values. */
798         if (get_options(d) != SRD_OK) {
799                 fail_txt = "cannot get options";
800                 goto err_out;
801         }
802
803         /* Check and import required channels. */
804         if (get_channels(d, "channels", &d->channels, 0) != SRD_OK) {
805                 fail_txt = "cannot get channels";
806                 goto err_out;
807         }
808
809         /* Check and import optional channels. */
810         if (get_channels(d, "optional_channels", &d->opt_channels,
811                                 g_slist_length(d->channels)) != SRD_OK) {
812                 fail_txt = "cannot get optional channels";
813                 goto err_out;
814         }
815
816         if (get_annotations(d) != SRD_OK) {
817                 fail_txt = "cannot get annotations";
818                 goto err_out;
819         }
820
821         if (get_annotation_rows(d) != SRD_OK) {
822                 fail_txt = "cannot get annotation rows";
823                 goto err_out;
824         }
825
826         if (get_binary_classes(d) != SRD_OK) {
827                 fail_txt = "cannot get binary classes";
828                 goto err_out;
829         }
830
831         PyGILState_Release(gstate);
832
833         /* Append it to the list of loaded decoders. */
834         pd_list = g_slist_append(pd_list, d);
835
836         return SRD_OK;
837
838 except_out:
839         /* Don't show a message for the "common" directory, it's not a PD. */
840         if (strcmp(module_name, "common")) {
841                 srd_exception_catch("Failed to load decoder %s: %s",
842                                     module_name, fail_txt);
843         }
844         fail_txt = NULL;
845 err_out:
846         if (fail_txt)
847                 srd_err("Failed to load decoder %s: %s", module_name, fail_txt);
848         decoder_free(d);
849         PyGILState_Release(gstate);
850
851         return SRD_ERR_PYTHON;
852 }
853
854 /**
855  * Return a protocol decoder's docstring.
856  *
857  * @param dec The loaded protocol decoder.
858  *
859  * @return A newly allocated buffer containing the protocol decoder's
860  *         documentation. The caller is responsible for free'ing the buffer.
861  *
862  * @since 0.1.0
863  */
864 SRD_API char *srd_decoder_doc_get(const struct srd_decoder *dec)
865 {
866         PyObject *py_str;
867         char *doc;
868         PyGILState_STATE gstate;
869
870         if (!srd_check_init())
871                 return NULL;
872
873         if (!dec)
874                 return NULL;
875
876         gstate = PyGILState_Ensure();
877
878         if (!PyObject_HasAttrString(dec->py_mod, "__doc__"))
879                 goto err;
880
881         if (!(py_str = PyObject_GetAttrString(dec->py_mod, "__doc__"))) {
882                 srd_exception_catch("Failed to get docstring");
883                 goto err;
884         }
885
886         doc = NULL;
887         if (py_str != Py_None)
888                 py_str_as_str(py_str, &doc);
889         Py_DECREF(py_str);
890
891         PyGILState_Release(gstate);
892
893         return doc;
894
895 err:
896         PyGILState_Release(gstate);
897
898         return NULL;
899 }
900
901 /**
902  * Unload the specified protocol decoder.
903  *
904  * @param dec The struct srd_decoder to be unloaded.
905  *
906  * @return SRD_OK upon success, a (negative) error code otherwise.
907  *
908  * @since 0.1.0
909  */
910 SRD_API int srd_decoder_unload(struct srd_decoder *dec)
911 {
912         struct srd_session *sess;
913         GSList *l;
914
915         if (!srd_check_init())
916                 return SRD_ERR;
917
918         if (!dec)
919                 return SRD_ERR_ARG;
920
921         /*
922          * Since any instances of this decoder need to be released as well,
923          * but they could be anywhere in the stack, just free the entire
924          * stack. A frontend reloading a decoder thus has to restart all
925          * instances, and rebuild the stack.
926          */
927         for (l = sessions; l; l = l->next) {
928                 sess = l->data;
929                 srd_inst_free_all(sess);
930         }
931
932         /* Remove the PD from the list of loaded decoders. */
933         pd_list = g_slist_remove(pd_list, dec);
934
935         decoder_free(dec);
936
937         return SRD_OK;
938 }
939
940 static void srd_decoder_load_all_zip_path(char *path)
941 {
942         PyObject *zipimport_mod, *zipimporter_class, *zipimporter;
943         PyObject *prefix_obj, *files, *key, *value, *set, *modname;
944         Py_ssize_t pos = 0;
945         char *prefix;
946         size_t prefix_len;
947         PyGILState_STATE gstate;
948
949         set = files = prefix_obj = zipimporter = zipimporter_class = NULL;
950
951         gstate = PyGILState_Ensure();
952
953         zipimport_mod = py_import_by_name("zipimport");
954         if (zipimport_mod == NULL)
955                 goto err_out;
956
957         zipimporter_class = PyObject_GetAttrString(zipimport_mod, "zipimporter");
958         if (zipimporter_class == NULL)
959                 goto err_out;
960
961         zipimporter = PyObject_CallFunction(zipimporter_class, "s", path);
962         if (zipimporter == NULL)
963                 goto err_out;
964
965         prefix_obj = PyObject_GetAttrString(zipimporter, "prefix");
966         if (prefix_obj == NULL)
967                 goto err_out;
968
969         files = PyObject_GetAttrString(zipimporter, "_files");
970         if (files == NULL || !PyDict_Check(files))
971                 goto err_out;
972
973         set = PySet_New(NULL);
974         if (set == NULL)
975                 goto err_out;
976
977         if (py_str_as_str(prefix_obj, &prefix) != SRD_OK)
978                 goto err_out;
979
980         prefix_len = strlen(prefix);
981
982         while (PyDict_Next(files, &pos, &key, &value)) {
983                 char *path, *slash;
984                 if (py_str_as_str(key, &path) == SRD_OK) {
985                         if (strlen(path) > prefix_len
986                                         && memcmp(path, prefix, prefix_len) == 0
987                                         && (slash = strchr(path + prefix_len, '/'))) {
988
989                                 modname = PyUnicode_FromStringAndSize(path + prefix_len,
990                                                         slash - (path + prefix_len));
991                                 if (modname == NULL) {
992                                         PyErr_Clear();
993                                 } else {
994                                         PySet_Add(set, modname);
995                                         Py_DECREF(modname);
996                                 }
997                         }
998                         g_free(path);
999                 }
1000         }
1001         g_free(prefix);
1002
1003         while ((modname = PySet_Pop(set))) {
1004                 char *modname_str;
1005                 if (py_str_as_str(modname, &modname_str) == SRD_OK) {
1006                         /* The directory name is the module name (e.g. "i2c"). */
1007                         srd_decoder_load(modname_str);
1008                         g_free(modname_str);
1009                 }
1010                 Py_DECREF(modname);
1011         }
1012
1013 err_out:
1014         Py_XDECREF(set);
1015         Py_XDECREF(files);
1016         Py_XDECREF(prefix_obj);
1017         Py_XDECREF(zipimporter);
1018         Py_XDECREF(zipimporter_class);
1019         Py_XDECREF(zipimport_mod);
1020         PyErr_Clear();
1021         PyGILState_Release(gstate);
1022 }
1023
1024 static void srd_decoder_load_all_path(char *path)
1025 {
1026         GDir *dir;
1027         const gchar *direntry;
1028
1029         if (!(dir = g_dir_open(path, 0, NULL))) {
1030                 /* Not really fatal */
1031                 /* Try zipimport method too */
1032                 srd_decoder_load_all_zip_path(path);
1033                 return;
1034         }
1035
1036         /* This ignores errors returned by srd_decoder_load(). That
1037          * function will have logged the cause, but in any case we
1038          * want to continue anyway. */
1039         while ((direntry = g_dir_read_name(dir)) != NULL) {
1040                 /* The directory name is the module name (e.g. "i2c"). */
1041                 srd_decoder_load(direntry);
1042         }
1043         g_dir_close(dir);
1044
1045 }
1046
1047 /**
1048  * Load all installed protocol decoders.
1049  *
1050  * @return SRD_OK upon success, a (negative) error code otherwise.
1051  *
1052  * @since 0.1.0
1053  */
1054 SRD_API int srd_decoder_load_all(void)
1055 {
1056         GSList *l;
1057
1058         if (!srd_check_init())
1059                 return SRD_ERR;
1060
1061         for (l = searchpaths; l; l = l->next)
1062                 srd_decoder_load_all_path(l->data);
1063
1064         return SRD_OK;
1065 }
1066
1067 /**
1068  * Unload all loaded protocol decoders.
1069  *
1070  * @return SRD_OK upon success, a (negative) error code otherwise.
1071  *
1072  * @since 0.1.0
1073  */
1074 SRD_API int srd_decoder_unload_all(void)
1075 {
1076         g_slist_foreach(pd_list, (GFunc)srd_decoder_unload, NULL);
1077         g_slist_free(pd_list);
1078         pd_list = NULL;
1079
1080         return SRD_OK;
1081 }
1082
1083 /** @} */