instance.c: Fix a memory leak reported by scan-build.
[libsigrokdecode.git] / decoder.c
index b5909168fec43b15528a1510ecc3d87eb750b9f2..21b756ba370620bf99db2aefb8a31f0f7f9c6b10 100644 (file)
--- a/decoder.c
+++ b/decoder.c
@@ -1,8 +1,8 @@
 /*
- * This file is part of the sigrok project.
+ * This file is part of the libsigrokdecode project.
  *
  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
- * Copyright (C) 2011 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "config.h"
-#include "sigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
-#include "sigrokdecode-internal.h"
-#include <dirent.h>
+#include <config.h>
+#include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
+#include "libsigrokdecode.h"
+#include <glib.h>
 
-/* The list of protocol decoders. */
-GSList *pd_list = NULL;
-GSList *di_list = NULL;
+/**
+ * @file
+ *
+ * Listing, loading, unloading, and handling protocol decoders.
+ */
+
+/**
+ * @defgroup grp_decoder Protocol decoders
+ *
+ * Handling protocol decoders.
+ *
+ * @{
+ */
+
+/** @cond PRIVATE */
+
+/* The list of loaded protocol decoders. */
+static GSList *pd_list = NULL;
 
+/* srd.c */
+extern SRD_PRIV GSList *searchpaths;
+
+/* session.c */
+extern SRD_PRIV GSList *sessions;
+extern SRD_PRIV int max_session_id;
+
+/* module_sigrokdecode.c */
+extern SRD_PRIV PyObject *mod_sigrokdecode;
+
+/** @endcond */
+
+static gboolean srd_check_init(void)
+{
+       if (max_session_id < 0) {
+               srd_err("Library is not initialized.");
+               return FALSE;
+       } else
+               return TRUE;
+}
 
 /**
- * Returns the list of supported/loaded protocol decoders.
+ * Returns the list of loaded protocol decoders.
  *
- * This is a GSList containing the names of the decoders as strings.
+ * This is a GSList of pointers to struct srd_decoder items.
  *
  * @return List of decoders, NULL if none are supported or loaded.
+ *
+ * @since 0.2.0
  */
-GSList *srd_list_decoders(void)
+SRD_API const GSList *srd_decoder_list(void)
 {
-
        return pd_list;
 }
 
-
 /**
  * Get the decoder with the specified ID.
  *
  * @param id The ID string of the decoder to return.
+ *
  * @return The decoder with the specified ID, or NULL if not found.
+ *
+ * @since 0.1.0
  */
-struct srd_decoder *srd_get_decoder_by_id(const char *id)
+SRD_API struct srd_decoder *srd_decoder_get_by_id(const char *id)
 {
        GSList *l;
        struct srd_decoder *dec;
 
-       for (l = srd_list_decoders(); l; l = l->next) {
+       for (l = pd_list; l; l = l->next) {
                dec = l->data;
                if (!strcmp(dec->id, id))
                        return dec;
@@ -62,186 +100,984 @@ struct srd_decoder *srd_get_decoder_by_id(const char *id)
        return NULL;
 }
 
+static void channel_free(void *data)
+{
+       struct srd_channel *ch = data;
+
+       if (!ch)
+               return;
+
+       g_free(ch->desc);
+       g_free(ch->name);
+       g_free(ch->id);
+       g_free(ch);
+}
+
+static void variant_free(void *data)
+{
+       GVariant *var = data;
+
+       if (!var)
+               return;
+
+       g_variant_unref(var);
+}
+
+static void annotation_row_free(void *data)
+{
+       struct srd_decoder_annotation_row *row = data;
+
+       if (!row)
+               return;
+
+       g_slist_free(row->ann_classes);
+       g_free(row->desc);
+       g_free(row->id);
+       g_free(row);
+}
+
+static void decoder_option_free(void *data)
+{
+       struct srd_decoder_option *opt = data;
+
+       if (!opt)
+               return;
+
+       g_slist_free_full(opt->values, &variant_free);
+       variant_free(opt->def);
+       g_free(opt->desc);
+       g_free(opt->id);
+       g_free(opt);
+}
+
+static void decoder_free(struct srd_decoder *dec)
+{
+       PyGILState_STATE gstate;
+
+       if (!dec)
+               return;
+
+       gstate = PyGILState_Ensure();
+       Py_XDECREF(dec->py_dec);
+       Py_XDECREF(dec->py_mod);
+       PyGILState_Release(gstate);
+
+       g_slist_free_full(dec->options, &decoder_option_free);
+       g_slist_free_full(dec->binary, (GDestroyNotify)&g_strfreev);
+       g_slist_free_full(dec->annotation_rows, &annotation_row_free);
+       g_slist_free_full(dec->annotations, (GDestroyNotify)&g_strfreev);
+       g_slist_free_full(dec->opt_channels, &channel_free);
+       g_slist_free_full(dec->channels, &channel_free);
+
+       g_slist_free_full(dec->outputs, g_free);
+       g_slist_free_full(dec->inputs, g_free);
+       g_free(dec->license);
+       g_free(dec->desc);
+       g_free(dec->longname);
+       g_free(dec->name);
+       g_free(dec->id);
+
+       g_free(dec);
+}
+
+static int get_channels(const struct srd_decoder *d, const char *attr,
+               GSList **out_pdchl, int offset)
+{
+       PyObject *py_channellist, *py_entry;
+       struct srd_channel *pdch;
+       GSList *pdchl;
+       ssize_t i;
+       PyGILState_STATE gstate;
+
+       gstate = PyGILState_Ensure();
+
+       if (!PyObject_HasAttrString(d->py_dec, attr)) {
+               /* No channels of this type specified. */
+               PyGILState_Release(gstate);
+               return SRD_OK;
+       }
+
+       pdchl = NULL;
+
+       py_channellist = PyObject_GetAttrString(d->py_dec, attr);
+       if (!py_channellist)
+               goto except_out;
+
+       if (!PyTuple_Check(py_channellist)) {
+               srd_err("Protocol decoder %s %s attribute is not a tuple.",
+                       d->name, attr);
+               goto err_out;
+       }
+
+       for (i = PyTuple_Size(py_channellist) - 1; i >= 0; i--) {
+               py_entry = PyTuple_GetItem(py_channellist, i);
+               if (!py_entry)
+                       goto except_out;
+
+               if (!PyDict_Check(py_entry)) {
+                       srd_err("Protocol decoder %s %s attribute is not "
+                               "a list of dict elements.", d->name, attr);
+                       goto err_out;
+               }
+               pdch = g_malloc(sizeof(struct srd_channel));
+               /* Add to list right away so it doesn't get lost. */
+               pdchl = g_slist_prepend(pdchl, pdch);
+
+               if (py_dictitem_as_str(py_entry, "id", &pdch->id) != SRD_OK)
+                       goto err_out;
+               if (py_dictitem_as_str(py_entry, "name", &pdch->name) != SRD_OK)
+                       goto err_out;
+               if (py_dictitem_as_str(py_entry, "desc", &pdch->desc) != SRD_OK)
+                       goto err_out;
+
+               pdch->order = offset + i;
+       }
+
+       Py_DECREF(py_channellist);
+       *out_pdchl = pdchl;
+
+       PyGILState_Release(gstate);
+
+       return SRD_OK;
+
+except_out:
+       srd_exception_catch("Failed to get %s list of %s decoder",
+                       attr, d->name);
+err_out:
+       g_slist_free_full(pdchl, &channel_free);
+       Py_XDECREF(py_channellist);
+       PyGILState_Release(gstate);
+
+       return SRD_ERR_PYTHON;
+}
+
+static int get_options(struct srd_decoder *d)
+{
+       PyObject *py_opts, *py_opt, *py_str, *py_values, *py_default, *py_item;
+       GSList *options;
+       struct srd_decoder_option *o;
+       GVariant *gvar;
+       ssize_t opt, i;
+       PyGILState_STATE gstate;
+
+       gstate = PyGILState_Ensure();
+
+       if (!PyObject_HasAttrString(d->py_dec, "options")) {
+               /* No options, that's fine. */
+               PyGILState_Release(gstate);
+               return SRD_OK;
+       }
+
+       options = NULL;
+
+       /* If present, options must be a tuple. */
+       py_opts = PyObject_GetAttrString(d->py_dec, "options");
+       if (!py_opts)
+               goto except_out;
+
+       if (!PyTuple_Check(py_opts)) {
+               srd_err("Protocol decoder %s: options attribute is not "
+                               "a tuple.", d->id);
+               goto err_out;
+       }
+
+       for (opt = PyTuple_Size(py_opts) - 1; opt >= 0; opt--) {
+               py_opt = PyTuple_GetItem(py_opts, opt);
+               if (!py_opt)
+                       goto except_out;
+
+               if (!PyDict_Check(py_opt)) {
+                       srd_err("Protocol decoder %s options: each option "
+                                       "must consist of a dictionary.", d->name);
+                       goto err_out;
+               }
+
+               o = g_malloc0(sizeof(struct srd_decoder_option));
+               /* Add to list right away so it doesn't get lost. */
+               options = g_slist_prepend(options, o);
+
+               py_str = PyDict_GetItemString(py_opt, "id");
+               if (!py_str) {
+                       srd_err("Protocol decoder %s option %zd has no ID.",
+                               d->name, opt);
+                       goto err_out;
+               }
+               if (py_str_as_str(py_str, &o->id) != SRD_OK)
+                       goto err_out;
+
+               py_str = PyDict_GetItemString(py_opt, "desc");
+               if (py_str) {
+                       if (py_str_as_str(py_str, &o->desc) != SRD_OK)
+                               goto err_out;
+               }
+
+               py_default = PyDict_GetItemString(py_opt, "default");
+               if (py_default) {
+                       gvar = py_obj_to_variant(py_default);
+                       if (!gvar) {
+                               srd_err("Protocol decoder %s option 'default' has "
+                                       "invalid default value.", d->name);
+                               goto err_out;
+                       }
+                       o->def = g_variant_ref_sink(gvar);
+               }
+
+               py_values = PyDict_GetItemString(py_opt, "values");
+               if (py_values) {
+                       /* A default is required if a list of values is
+                        * given, since it's used to verify their type. */
+                       if (!o->def) {
+                               srd_err("No default for option '%s'.", o->id);
+                               goto err_out;
+                       }
+                       if (!PyTuple_Check(py_values)) {
+                               srd_err("Option '%s' values should be a tuple.", o->id);
+                               goto err_out;
+                       }
+
+                       for (i = PyTuple_Size(py_values) - 1; i >= 0; i--) {
+                               py_item = PyTuple_GetItem(py_values, i);
+                               if (!py_item)
+                                       goto except_out;
+
+                               if (Py_TYPE(py_default) != Py_TYPE(py_item)) {
+                                       srd_err("All values for option '%s' must be "
+                                               "of the same type as the default.",
+                                               o->id);
+                                       goto err_out;
+                               }
+                               gvar = py_obj_to_variant(py_item);
+                               if (!gvar) {
+                                       srd_err("Protocol decoder %s option 'values' "
+                                               "contains invalid value.", d->name);
+                                       goto err_out;
+                               }
+                               o->values = g_slist_prepend(o->values,
+                                               g_variant_ref_sink(gvar));
+                       }
+               }
+       }
+       d->options = options;
+       Py_DECREF(py_opts);
+       PyGILState_Release(gstate);
+
+       return SRD_OK;
+
+except_out:
+       srd_exception_catch("Failed to get %s decoder options", d->name);
+err_out:
+       g_slist_free_full(options, &decoder_option_free);
+       Py_XDECREF(py_opts);
+       PyGILState_Release(gstate);
+
+       return SRD_ERR_PYTHON;
+}
+
+/* Convert annotation class attribute to GSList of char **.
+ */
+static int get_annotations(struct srd_decoder *dec)
+{
+       PyObject *py_annlist, *py_ann;
+       GSList *annotations;
+       char **annpair;
+       ssize_t i;
+       PyGILState_STATE gstate;
+
+       gstate = PyGILState_Ensure();
+
+       if (!PyObject_HasAttrString(dec->py_dec, "annotations")) {
+               PyGILState_Release(gstate);
+               return SRD_OK;
+       }
+
+       annotations = NULL;
+
+       py_annlist = PyObject_GetAttrString(dec->py_dec, "annotations");
+       if (!py_annlist)
+               goto except_out;
+
+       if (!PyTuple_Check(py_annlist)) {
+               srd_err("Protocol decoder %s annotations should "
+                       "be a tuple.", dec->name);
+               goto err_out;
+       }
+
+       for (i = PyTuple_Size(py_annlist) - 1; i >= 0; i--) {
+               py_ann = PyTuple_GetItem(py_annlist, i);
+               if (!py_ann)
+                       goto except_out;
+
+               if (!PyTuple_Check(py_ann) || PyTuple_Size(py_ann) != 2) {
+                       srd_err("Protocol decoder %s annotation %zd should "
+                               "be a tuple with two elements.",
+                               dec->name, i + 1);
+                       goto err_out;
+               }
+               if (py_strseq_to_char(py_ann, &annpair) != SRD_OK)
+                       goto err_out;
+
+               annotations = g_slist_prepend(annotations, annpair);
+       }
+       dec->annotations = annotations;
+       Py_DECREF(py_annlist);
+       PyGILState_Release(gstate);
+
+       return SRD_OK;
+
+except_out:
+       srd_exception_catch("Failed to get %s decoder annotations", dec->name);
+err_out:
+       g_slist_free_full(annotations, (GDestroyNotify)&g_strfreev);
+       Py_XDECREF(py_annlist);
+       PyGILState_Release(gstate);
+
+       return SRD_ERR_PYTHON;
+}
+
+/* Convert annotation_rows to GSList of 'struct srd_decoder_annotation_row'.
+ */
+static int get_annotation_rows(struct srd_decoder *dec)
+{
+       PyObject *py_ann_rows, *py_ann_row, *py_ann_classes, *py_item;
+       GSList *annotation_rows;
+       struct srd_decoder_annotation_row *ann_row;
+       ssize_t i, k;
+       size_t class_idx;
+       PyGILState_STATE gstate;
+
+       gstate = PyGILState_Ensure();
+
+       if (!PyObject_HasAttrString(dec->py_dec, "annotation_rows")) {
+               PyGILState_Release(gstate);
+               return SRD_OK;
+       }
+
+       annotation_rows = NULL;
+
+       py_ann_rows = PyObject_GetAttrString(dec->py_dec, "annotation_rows");
+       if (!py_ann_rows)
+               goto except_out;
+
+       if (!PyTuple_Check(py_ann_rows)) {
+               srd_err("Protocol decoder %s annotation_rows "
+                       "must be a tuple.", dec->name);
+               goto err_out;
+       }
+
+       for (i = PyTuple_Size(py_ann_rows) - 1; i >= 0; i--) {
+               py_ann_row = PyTuple_GetItem(py_ann_rows, i);
+               if (!py_ann_row)
+                       goto except_out;
+
+               if (!PyTuple_Check(py_ann_row) || PyTuple_Size(py_ann_row) != 3) {
+                       srd_err("Protocol decoder %s annotation_rows "
+                               "must contain only tuples of 3 elements.",
+                               dec->name);
+                       goto err_out;
+               }
+               ann_row = g_malloc0(sizeof(struct srd_decoder_annotation_row));
+               /* Add to list right away so it doesn't get lost. */
+               annotation_rows = g_slist_prepend(annotation_rows, ann_row);
+
+               py_item = PyTuple_GetItem(py_ann_row, 0);
+               if (!py_item)
+                       goto except_out;
+               if (py_str_as_str(py_item, &ann_row->id) != SRD_OK)
+                       goto err_out;
+
+               py_item = PyTuple_GetItem(py_ann_row, 1);
+               if (!py_item)
+                       goto except_out;
+               if (py_str_as_str(py_item, &ann_row->desc) != SRD_OK)
+                       goto err_out;
+
+               py_ann_classes = PyTuple_GetItem(py_ann_row, 2);
+               if (!py_ann_classes)
+                       goto except_out;
+
+               if (!PyTuple_Check(py_ann_classes)) {
+                       srd_err("Protocol decoder %s annotation_rows tuples "
+                               "must have a tuple of numbers as 3rd element.",
+                               dec->name);
+                       goto err_out;
+               }
+
+               for (k = PyTuple_Size(py_ann_classes) - 1; k >= 0; k--) {
+                       py_item = PyTuple_GetItem(py_ann_classes, k);
+                       if (!py_item)
+                               goto except_out;
+
+                       if (!PyLong_Check(py_item)) {
+                               srd_err("Protocol decoder %s annotation row "
+                                       "class tuple must only contain numbers.",
+                                       dec->name);
+                               goto err_out;
+                       }
+                       class_idx = PyLong_AsSize_t(py_item);
+                       if (PyErr_Occurred())
+                               goto except_out;
+
+                       ann_row->ann_classes = g_slist_prepend(ann_row->ann_classes,
+                                       GSIZE_TO_POINTER(class_idx));
+               }
+       }
+       dec->annotation_rows = annotation_rows;
+       Py_DECREF(py_ann_rows);
+       PyGILState_Release(gstate);
+
+       return SRD_OK;
+
+except_out:
+       srd_exception_catch("Failed to get %s decoder annotation rows",
+                       dec->name);
+err_out:
+       g_slist_free_full(annotation_rows, &annotation_row_free);
+       Py_XDECREF(py_ann_rows);
+       PyGILState_Release(gstate);
+
+       return SRD_ERR_PYTHON;
+}
+
+/* Convert binary classes to GSList of char **.
+ */
+static int get_binary_classes(struct srd_decoder *dec)
+{
+       PyObject *py_bin_classes, *py_bin_class;
+       GSList *bin_classes;
+       char **bin;
+       ssize_t i;
+       PyGILState_STATE gstate;
+
+       gstate = PyGILState_Ensure();
+
+       if (!PyObject_HasAttrString(dec->py_dec, "binary")) {
+               PyGILState_Release(gstate);
+               return SRD_OK;
+       }
+
+       bin_classes = NULL;
+
+       py_bin_classes = PyObject_GetAttrString(dec->py_dec, "binary");
+       if (!py_bin_classes)
+               goto except_out;
+
+       if (!PyTuple_Check(py_bin_classes)) {
+               srd_err("Protocol decoder %s binary classes should "
+                       "be a tuple.", dec->name);
+               goto err_out;
+       }
+
+       for (i = PyTuple_Size(py_bin_classes) - 1; i >= 0; i--) {
+               py_bin_class = PyTuple_GetItem(py_bin_classes, i);
+               if (!py_bin_class)
+                       goto except_out;
+
+               if (!PyTuple_Check(py_bin_class)
+                               || PyTuple_Size(py_bin_class) != 2) {
+                       srd_err("Protocol decoder %s binary classes should "
+                               "consist only of tuples of 2 elements.",
+                               dec->name);
+                       goto err_out;
+               }
+               if (py_strseq_to_char(py_bin_class, &bin) != SRD_OK)
+                       goto err_out;
+
+               bin_classes = g_slist_prepend(bin_classes, bin);
+       }
+       dec->binary = bin_classes;
+       Py_DECREF(py_bin_classes);
+       PyGILState_Release(gstate);
+
+       return SRD_OK;
+
+except_out:
+       srd_exception_catch("Failed to get %s decoder binary classes",
+                       dec->name);
+err_out:
+       g_slist_free_full(bin_classes, (GDestroyNotify)&g_strfreev);
+       Py_XDECREF(py_bin_classes);
+       PyGILState_Release(gstate);
+
+       return SRD_ERR_PYTHON;
+}
+
+/* Check whether the Decoder class defines the named method.
+ */
+static int check_method(PyObject *py_dec, const char *mod_name,
+               const char *method_name)
+{
+       PyObject *py_method;
+       int is_callable;
+       PyGILState_STATE gstate;
+
+       gstate = PyGILState_Ensure();
+
+       py_method = PyObject_GetAttrString(py_dec, method_name);
+       if (!py_method) {
+               srd_exception_catch("Protocol decoder %s Decoder class "
+                               "has no %s() method", mod_name, method_name);
+               PyGILState_Release(gstate);
+               return SRD_ERR_PYTHON;
+       }
+
+       is_callable = PyCallable_Check(py_method);
+       Py_DECREF(py_method);
+
+       PyGILState_Release(gstate);
+
+       if (!is_callable) {
+               srd_err("Protocol decoder %s Decoder class attribute '%s' "
+                       "is not a method.", mod_name, method_name);
+               return SRD_ERR_PYTHON;
+       }
+
+       return SRD_OK;
+}
 
 /**
- * Load a protocol decoder module into the embedded python interpreter.
+ * Get the API version of the specified decoder.
+ *
+ * @param d The decoder to use. Must not be NULL.
  *
- * @param name The module name to be loaded.
- * @param dec Pointer to the struct srd_decoder filled with the loaded module.
+ * @return The API version of the decoder, or 0 upon errors.
+ *
+ * @private
+ */
+SRD_PRIV long srd_decoder_apiver(const struct srd_decoder *d)
+{
+       PyObject *py_apiver;
+       long apiver;
+       PyGILState_STATE gstate;
+
+       if (!d)
+               return 0;
+
+       gstate = PyGILState_Ensure();
+
+       py_apiver = PyObject_GetAttrString(d->py_dec, "api_version");
+       apiver = (py_apiver && PyLong_Check(py_apiver))
+                       ? PyLong_AsLong(py_apiver) : 0;
+       Py_XDECREF(py_apiver);
+
+       PyGILState_Release(gstate);
+
+       return apiver;
+}
+
+/**
+ * Load a protocol decoder module into the embedded Python interpreter.
+ *
+ * @param module_name The module name to be loaded.
  *
  * @return SRD_OK upon success, a (negative) error code otherwise.
+ *
+ * @since 0.1.0
  */
-int srd_load_decoder(const char *name, struct srd_decoder **dec)
+SRD_API int srd_decoder_load(const char *module_name)
 {
-       PyObject *py_mod, *py_res, *py_annlist, *py_ann;
+       PyObject *py_basedec;
        struct srd_decoder *d;
-       int alen, r, i;
-       char **ann;
+       long apiver;
+       int is_subclass;
+       const char *fail_txt;
+       PyGILState_STATE gstate;
+
+       if (!srd_check_init())
+               return SRD_ERR;
+
+       if (!module_name)
+               return SRD_ERR_ARG;
 
-       fprintf(stdout, "%s: %s\n", __func__, name);
+       gstate = PyGILState_Ensure();
 
-       /* "Import" the Python module. */
-       if (!(py_mod = PyImport_ImportModule(name))) { /* NEWREF */
-               PyErr_Print(); /* Returns void. */
-               return SRD_ERR_PYTHON; /* TODO: More specific error? */
+       if (PyDict_GetItemString(PyImport_GetModuleDict(), module_name)) {
+               /* Module was already imported. */
+               PyGILState_Release(gstate);
+               return SRD_OK;
+       }
+
+       d = g_malloc0(sizeof(struct srd_decoder));
+       fail_txt = NULL;
+
+       d->py_mod = py_import_by_name(module_name);
+       if (!d->py_mod) {
+               fail_txt = "import by name failed";
+               goto except_out;
+       }
+
+       if (!mod_sigrokdecode) {
+               srd_err("sigrokdecode module not loaded.");
+               fail_txt = "sigrokdecode(3) not loaded";
+               goto err_out;
        }
 
        /* Get the 'Decoder' class as Python object. */
-       py_res = PyObject_GetAttrString(py_mod, "Decoder"); /* NEWREF */
-       if (!py_res) {
-               if (PyErr_Occurred())
-                       PyErr_Print(); /* Returns void. */
-               Py_XDECREF(py_mod);
-               fprintf(stderr, "Decoder class not found in PD module %s\n", name);
-               return SRD_ERR_PYTHON; /* TODO: More specific error? */
+       d->py_dec = PyObject_GetAttrString(d->py_mod, "Decoder");
+       if (!d->py_dec) {
+               fail_txt = "no 'Decoder' attribute in imported module";
+               goto except_out;
+       }
+
+       py_basedec = PyObject_GetAttrString(mod_sigrokdecode, "Decoder");
+       if (!py_basedec) {
+               fail_txt = "no 'Decoder' attribute in sigrokdecode(3)";
+               goto except_out;
        }
 
-       if (!(d = malloc(sizeof(struct srd_decoder))))
-               return SRD_ERR_MALLOC;
+       is_subclass = PyObject_IsSubclass(d->py_dec, py_basedec);
+       Py_DECREF(py_basedec);
 
-       if ((r = h_str(py_res, "id", &(d->id))) < 0)
-               return r;
+       if (!is_subclass) {
+               srd_err("Decoder class in protocol decoder module %s is not "
+                       "a subclass of sigrokdecode.Decoder.", module_name);
+               fail_txt = "not a subclass of sigrokdecode.Decoder";
+               goto err_out;
+       }
 
-       if ((r = h_str(py_res, "name", &(d->name))) < 0)
-               return r;
+       /*
+        * Check that this decoder has the correct PD API version.
+        * PDs of different API versions are incompatible and cannot work.
+        */
+       apiver = srd_decoder_apiver(d);
+       if (apiver != 3) {
+               srd_exception_catch("Only PD API version 3 is supported, "
+                       "decoder %s has version %ld", module_name, apiver);
+               fail_txt = "API version mismatch";
+               goto err_out;
+       }
 
-       if ((r = h_str(py_res, "longname", &(d->longname))) < 0)
-               return r;
+       /* Check Decoder class for required methods.
+        */
+       if (check_method(d->py_dec, module_name, "start") != SRD_OK) {
+               fail_txt = "no 'start()' method";
+               goto err_out;
+       }
 
-       if ((r = h_str(py_res, "desc", &(d->desc))) < 0)
-               return r;
+       if (check_method(d->py_dec, module_name, "decode") != SRD_OK) {
+               fail_txt = "no 'decode()' method";
+               goto err_out;
+       }
 
-       if ((r = h_str(py_res, "longdesc", &(d->longdesc))) < 0)
-               return r;
+       /* Store required fields in newly allocated strings. */
+       if (py_attr_as_str(d->py_dec, "id", &(d->id)) != SRD_OK) {
+               fail_txt = "no 'id' attribute";
+               goto err_out;
+       }
 
-       if ((r = h_str(py_res, "author", &(d->author))) < 0)
-               return r;
+       if (py_attr_as_str(d->py_dec, "name", &(d->name)) != SRD_OK) {
+               fail_txt = "no 'name' attribute";
+               goto err_out;
+       }
 
-       if ((r = h_str(py_res, "email", &(d->email))) < 0)
-               return r;
+       if (py_attr_as_str(d->py_dec, "longname", &(d->longname)) != SRD_OK) {
+               fail_txt = "no 'longname' attribute";
+               goto err_out;
+       }
 
-       if ((r = h_str(py_res, "license", &(d->license))) < 0)
-               return r;
+       if (py_attr_as_str(d->py_dec, "desc", &(d->desc)) != SRD_OK) {
+               fail_txt = "no 'desc' attribute";
+               goto err_out;
+       }
 
-       d->py_mod = py_mod;
-       d->py_decobj = py_res;
+       if (py_attr_as_str(d->py_dec, "license", &(d->license)) != SRD_OK) {
+               fail_txt = "no 'license' attribute";
+               goto err_out;
+       }
 
-       /* TODO: Handle func, inputformats, outputformats. */
-       /* Note: They must at least be set to NULL, will segfault otherwise. */
-       d->func = NULL;
-       d->inputformats = NULL;
-       d->outputformats = NULL;
+       if (py_attr_as_strlist(d->py_dec, "inputs", &(d->inputs)) != SRD_OK) {
+               fail_txt = "missing or malformed 'inputs' attribute";
+               goto err_out;
+       }
 
-       /* Convert class annotation attribute to GSList of **char */
-       d->annotation = NULL;
-       if ((py_annlist = PyObject_GetAttrString(py_res, "annotation"))) {
-               if (!PyList_Check(py_annlist)) {
-                       srd_err("Protocol decoder module %s annotation should be a list", name);
-                       return SRD_ERR_PYTHON;
-               }
-               alen = PyList_Size(py_annlist);
-               for (i = 0; i < alen; i++) {
-                       py_ann = PyList_GetItem(py_annlist, i);
-                       if (!PyList_Check(py_ann) || PyList_Size(py_ann) != 2) {
-                               srd_err("Protocol decoder module %s annotation %d should be a list with two elements",
-                                               name, i+1);
-                               return SRD_ERR_PYTHON;
-                       }
+       if (py_attr_as_strlist(d->py_dec, "outputs", &(d->outputs)) != SRD_OK) {
+               fail_txt = "missing or malformed 'outputs' attribute";
+               goto err_out;
+       }
 
-                       if (py_strlist_to_char(py_ann, &ann) != SRD_OK)
-                               return SRD_ERR_PYTHON;
-                       d->annotation = g_slist_append(d->annotation, ann);
-               }
+       /* All options and their default values. */
+       if (get_options(d) != SRD_OK) {
+               fail_txt = "cannot get options";
+               goto err_out;
        }
 
-       *dec = d;
+       /* Check and import required channels. */
+       if (get_channels(d, "channels", &d->channels, 0) != SRD_OK) {
+               fail_txt = "cannot get channels";
+               goto err_out;
+       }
+
+       /* Check and import optional channels. */
+       if (get_channels(d, "optional_channels", &d->opt_channels,
+                               g_slist_length(d->channels)) != SRD_OK) {
+               fail_txt = "cannot get optional channels";
+               goto err_out;
+       }
+
+       if (get_annotations(d) != SRD_OK) {
+               fail_txt = "cannot get annotations";
+               goto err_out;
+       }
+
+       if (get_annotation_rows(d) != SRD_OK) {
+               fail_txt = "cannot get annotation rows";
+               goto err_out;
+       }
+
+       if (get_binary_classes(d) != SRD_OK) {
+               fail_txt = "cannot get binary classes";
+               goto err_out;
+       }
+
+       PyGILState_Release(gstate);
+
+       /* Append it to the list of loaded decoders. */
+       pd_list = g_slist_append(pd_list, d);
 
        return SRD_OK;
+
+except_out:
+       /* Don't show a message for the "common" directory, it's not a PD. */
+       if (strcmp(module_name, "common")) {
+               srd_exception_catch("Failed to load decoder %s: %s",
+                                   module_name, fail_txt);
+       }
+       fail_txt = NULL;
+err_out:
+       if (fail_txt)
+               srd_err("Failed to load decoder %s: %s", module_name, fail_txt);
+       decoder_free(d);
+       PyGILState_Release(gstate);
+
+       return SRD_ERR_PYTHON;
 }
 
+/**
+ * Return a protocol decoder's docstring.
+ *
+ * @param dec The loaded protocol decoder.
+ *
+ * @return A newly allocated buffer containing the protocol decoder's
+ *         documentation. The caller is responsible for free'ing the buffer.
+ *
+ * @since 0.1.0
+ */
+SRD_API char *srd_decoder_doc_get(const struct srd_decoder *dec)
+{
+       PyObject *py_str;
+       char *doc;
+       PyGILState_STATE gstate;
+
+       if (!srd_check_init())
+               return NULL;
+
+       if (!dec)
+               return NULL;
+
+       gstate = PyGILState_Ensure();
+
+       if (!PyObject_HasAttrString(dec->py_mod, "__doc__"))
+               goto err;
+
+       if (!(py_str = PyObject_GetAttrString(dec->py_mod, "__doc__"))) {
+               srd_exception_catch("Failed to get docstring");
+               goto err;
+       }
+
+       doc = NULL;
+       if (py_str != Py_None)
+               py_str_as_str(py_str, &doc);
+       Py_DECREF(py_str);
+
+       PyGILState_Release(gstate);
+
+       return doc;
+
+err:
+       PyGILState_Release(gstate);
+
+       return NULL;
+}
 
 /**
- * TODO
+ * Unload the specified protocol decoder.
+ *
+ * @param dec The struct srd_decoder to be unloaded.
+ *
+ * @return SRD_OK upon success, a (negative) error code otherwise.
+ *
+ * @since 0.1.0
  */
-int srd_unload_decoder(struct srd_decoder *dec)
+SRD_API int srd_decoder_unload(struct srd_decoder *dec)
 {
-       g_free(dec->id);
-       g_free(dec->name);
-       g_free(dec->desc);
-       g_free(dec->func);
+       struct srd_session *sess;
+       GSList *l;
 
-       /* TODO: Free everything in inputformats and outputformats. */
+       if (!srd_check_init())
+               return SRD_ERR;
 
-       if (dec->inputformats != NULL)
-               g_slist_free(dec->inputformats);
-       if (dec->outputformats != NULL)
-               g_slist_free(dec->outputformats);
+       if (!dec)
+               return SRD_ERR_ARG;
 
-       Py_XDECREF(dec->py_decobj);
-       Py_XDECREF(dec->py_mod);
+       /*
+        * Since any instances of this decoder need to be released as well,
+        * but they could be anywhere in the stack, just free the entire
+        * stack. A frontend reloading a decoder thus has to restart all
+        * instances, and rebuild the stack.
+        */
+       for (l = sessions; l; l = l->next) {
+               sess = l->data;
+               srd_inst_free_all(sess);
+       }
+
+       /* Remove the PD from the list of loaded decoders. */
+       pd_list = g_slist_remove(pd_list, dec);
 
-       /* TODO: (g_)free dec itself? */
+       decoder_free(dec);
 
        return SRD_OK;
 }
 
-
-int srd_load_all_decoders(void)
+static void srd_decoder_load_all_zip_path(char *path)
 {
-       DIR *dir;
-       struct dirent *dp;
-       int ret;
-       char *decodername;
-       struct srd_decoder *dec;
+       PyObject *zipimport_mod, *zipimporter_class, *zipimporter;
+       PyObject *prefix_obj, *files, *key, *value, *set, *modname;
+       Py_ssize_t pos = 0;
+       char *prefix;
+       size_t prefix_len;
+       PyGILState_STATE gstate;
 
-       if (!(dir = opendir(DECODERS_DIR))) {
-               Py_Finalize(); /* Returns void. */
-               return SRD_ERR_DECODERS_DIR;
-       }
+       set = files = prefix_obj = zipimporter = zipimporter_class = NULL;
+
+       gstate = PyGILState_Ensure();
+
+       zipimport_mod = py_import_by_name("zipimport");
+       if (zipimport_mod == NULL)
+               goto err_out;
+
+       zipimporter_class = PyObject_GetAttrString(zipimport_mod, "zipimporter");
+       if (zipimporter_class == NULL)
+               goto err_out;
+
+       zipimporter = PyObject_CallFunction(zipimporter_class, "s", path);
+       if (zipimporter == NULL)
+               goto err_out;
+
+       prefix_obj = PyObject_GetAttrString(zipimporter, "prefix");
+       if (prefix_obj == NULL)
+               goto err_out;
 
-       while ((dp = readdir(dir)) != NULL) {
-               /* Ignore filenames which don't end with ".py". */
-               if (!g_str_has_suffix(dp->d_name, ".py"))
-                       continue;
+       files = PyObject_GetAttrString(zipimporter, "_files");
+       if (files == NULL || !PyDict_Check(files))
+               goto err_out;
 
-               /* Decoder name == filename (without .py suffix). */
-               decodername = g_strndup(dp->d_name, strlen(dp->d_name) - 3);
+       set = PySet_New(NULL);
+       if (set == NULL)
+               goto err_out;
 
-               /* TODO: Error handling. Use g_try_malloc(). */
-               if (!(dec = malloc(sizeof(struct srd_decoder)))) {
-                       Py_Finalize(); /* Returns void. */
-                       return SRD_ERR_MALLOC;
+       if (py_str_as_str(prefix_obj, &prefix) != SRD_OK)
+               goto err_out;
+
+       prefix_len = strlen(prefix);
+
+       while (PyDict_Next(files, &pos, &key, &value)) {
+               char *path, *slash;
+               if (py_str_as_str(key, &path) == SRD_OK) {
+                       if (strlen(path) > prefix_len
+                                       && memcmp(path, prefix, prefix_len) == 0
+                                       && (slash = strchr(path + prefix_len, '/'))) {
+
+                               modname = PyUnicode_FromStringAndSize(path + prefix_len,
+                                                       slash - (path + prefix_len));
+                               if (modname == NULL) {
+                                       PyErr_Clear();
+                               } else {
+                                       PySet_Add(set, modname);
+                                       Py_DECREF(modname);
+                               }
+                       }
+                       g_free(path);
                }
+       }
+       g_free(prefix);
 
-               /* Load the decoder. */
-               /* TODO: Warning if loading fails for a decoder. */
-               if ((ret = srd_load_decoder(decodername, &dec)) == SRD_OK) {
-                       /* Append it to the list of supported/loaded decoders. */
-                       pd_list = g_slist_append(pd_list, dec);
+       while ((modname = PySet_Pop(set))) {
+               char *modname_str;
+               if (py_str_as_str(modname, &modname_str) == SRD_OK) {
+                       /* The directory name is the module name (e.g. "i2c"). */
+                       srd_decoder_load(modname_str);
+                       g_free(modname_str);
                }
+               Py_DECREF(modname);
        }
-       closedir(dir);
 
-       return SRD_OK;
+err_out:
+       Py_XDECREF(set);
+       Py_XDECREF(files);
+       Py_XDECREF(prefix_obj);
+       Py_XDECREF(zipimporter);
+       Py_XDECREF(zipimporter_class);
+       Py_XDECREF(zipimport_mod);
+       PyErr_Clear();
+       PyGILState_Release(gstate);
 }
 
+static void srd_decoder_load_all_path(char *path)
+{
+       GDir *dir;
+       const gchar *direntry;
+
+       if (!(dir = g_dir_open(path, 0, NULL))) {
+               /* Not really fatal */
+               /* Try zipimport method too */
+               srd_decoder_load_all_zip_path(path);
+               return;
+       }
+
+       /* This ignores errors returned by srd_decoder_load(). That
+        * function will have logged the cause, but in any case we
+        * want to continue anyway. */
+       while ((direntry = g_dir_read_name(dir)) != NULL) {
+               /* The directory name is the module name (e.g. "i2c"). */
+               srd_decoder_load(direntry);
+       }
+       g_dir_close(dir);
+
+}
 
 /**
- * TODO
+ * Load all installed protocol decoders.
+ *
+ * @return SRD_OK upon success, a (negative) error code otherwise.
+ *
+ * @since 0.1.0
  */
-int srd_unload_all_decoders(void)
+SRD_API int srd_decoder_load_all(void)
 {
        GSList *l;
-       struct srd_decoder *dec;
 
-       for (l = srd_list_decoders(); l; l = l->next) {
-               dec = l->data;
-               /* TODO: Error handling. */
-               srd_unload_decoder(dec);
-       }
+       if (!srd_check_init())
+               return SRD_ERR;
+
+       for (l = searchpaths; l; l = l->next)
+               srd_decoder_load_all_path(l->data);
 
        return SRD_OK;
 }
 
+/**
+ * Unload all loaded protocol decoders.
+ *
+ * @return SRD_OK upon success, a (negative) error code otherwise.
+ *
+ * @since 0.1.0
+ */
+SRD_API int srd_decoder_unload_all(void)
+{
+       g_slist_foreach(pd_list, (GFunc)srd_decoder_unload, NULL);
+       g_slist_free(pd_list);
+       pd_list = NULL;
 
+       return SRD_OK;
+}
 
+/** @} */