]> sigrok.org Git - libsigrok.git/blobdiff - bindings/cxx/classes.cpp
C++: Move C struct pointers out of ownership classes
[libsigrok.git] / bindings / cxx / classes.cpp
index a00f2967e45161e56b0d2df829cfa9c915ede926..7f5b3b2407e164d3f985bf7ef26578d5964ea162 100644 (file)
@@ -39,19 +39,16 @@ static void check(int result)
 }
 
 /** Helper function to obtain valid strings from possibly null input. */
-static const char *valid_string(const char *input)
+static inline const char *valid_string(const char *input)
 {
-       if (input != NULL)
-               return input;
-       else
-               return "";
+       return (input) ? input : "";
 }
 
 /** Helper function to convert between map<string, VariantBase> and GHashTable */
 static GHashTable *map_to_hash_variant(const map<string, Glib::VariantBase> &input)
 {
-       auto output = g_hash_table_new_full(
-               g_str_hash, g_str_equal, g_free, (GDestroyNotify) g_variant_unref);
+       auto output = g_hash_table_new_full(g_str_hash, g_str_equal, g_free,
+                       reinterpret_cast<GDestroyNotify>(&g_variant_unref));
        for (auto entry : input)
                g_hash_table_insert(output,
                        g_strdup(entry.first.c_str()),
@@ -63,12 +60,12 @@ Error::Error(int result) : result(result)
 {
 }
 
-const char *Error::what() const throw()
+const char *Error::what() const noexcept
 {
        return sr_strerror(result);
 }
 
-Error::~Error() throw()
+Error::~Error() noexcept
 {
 }
 
@@ -77,7 +74,7 @@ ResourceReader::~ResourceReader()
 }
 
 SR_PRIV int ResourceReader::open_callback(struct sr_resource *res,
-               const char *name, void *cb_data)
+               const char *name, void *cb_data) noexcept
 {
        try {
                auto *const reader = static_cast<ResourceReader*>(cb_data);
@@ -90,7 +87,8 @@ SR_PRIV int ResourceReader::open_callback(struct sr_resource *res,
        return SR_OK;
 }
 
-SR_PRIV int ResourceReader::close_callback(struct sr_resource *res, void *cb_data)
+SR_PRIV int ResourceReader::close_callback(struct sr_resource *res,
+               void *cb_data) noexcept
 {
        try {
                auto *const reader = static_cast<ResourceReader*>(cb_data);
@@ -104,7 +102,7 @@ SR_PRIV int ResourceReader::close_callback(struct sr_resource *res, void *cb_dat
 }
 
 SR_PRIV ssize_t ResourceReader::read_callback(const struct sr_resource *res,
-               void *buf, size_t count, void *cb_data)
+               void *buf, size_t count, void *cb_data) noexcept
 {
        try {
                auto *const reader = static_cast<ResourceReader*>(cb_data);
@@ -122,8 +120,8 @@ shared_ptr<Context> Context::create()
 }
 
 Context::Context() :
-       UserOwned(_structure),
-       _session(NULL)
+       _structure(nullptr),
+       _session(nullptr)
 {
        check(sr_init(&_structure));
 
@@ -161,7 +159,7 @@ map<string, shared_ptr<Driver>> Context::drivers()
        {
                auto name = entry.first;
                auto driver = entry.second;
-               result[name] = driver->get_shared_pointer(this);
+               result[name] = driver->share_owned_by(shared_from_this());
        }
        return result;
 }
@@ -173,7 +171,7 @@ map<string, shared_ptr<InputFormat>> Context::input_formats()
        {
                auto name = entry.first;
                auto input_format = entry.second;
-               result[name] = input_format->get_shared_pointer(this);
+               result[name] = input_format->share_owned_by(shared_from_this());
        }
        return result;
 }
@@ -185,7 +183,7 @@ map<string, shared_ptr<OutputFormat>> Context::output_formats()
        {
                auto name = entry.first;
                auto output_format = entry.second;
-               result[name] = output_format->get_shared_pointer(this);
+               result[name] = output_format->share_owned_by(shared_from_this());
        }
        return result;
 }
@@ -201,7 +199,7 @@ Context::~Context()
        check(sr_exit(_structure));
 }
 
-const LogLevel *Context::log_level()
+const LogLevel *Context::log_level() const
 {
        return LogLevel::get(sr_log_loglevel_get());
 }
@@ -211,22 +209,17 @@ void Context::set_log_level(const LogLevel *level)
        check(sr_log_loglevel_set(level->id()));
 }
 
-static int call_log_callback(void *cb_data, int loglevel, const char *format, va_list args)
+static int call_log_callback(void *cb_data, int loglevel,
+               const char *format, va_list args) noexcept
 {
-       va_list args_copy;
-       va_copy(args_copy, args);
-       int length = vsnprintf(NULL, 0, format, args_copy);
-       va_end(args_copy);
-       char *buf = (char *) g_malloc(length + 1);
-       vsprintf(buf, format, args);
-       string message(buf, length);
-       g_free(buf);
+       const unique_ptr<char, decltype(&g_free)>
+               message {g_strdup_vprintf(format, args), &g_free};
 
-       LogCallbackFunction callback = *((LogCallbackFunction *) cb_data);
+       auto *const callback = static_cast<LogCallbackFunction *>(cb_data);
 
        try
        {
-               callback(LogLevel::get(loglevel), message);
+               (*callback)(LogLevel::get(loglevel), message.get());
        }
        catch (Error e)
        {
@@ -332,9 +325,9 @@ shared_ptr<Packet> Context::create_analog_packet(
        for (auto channel : channels)
                meaning->channels = g_slist_append(meaning->channels, channel->_structure);
        analog->num_samples = num_samples;
-       meaning->mq = (sr_mq)mq->id();
-       meaning->unit = (sr_unit)unit->id();
-       meaning->mqflags = (sr_mqflag)QuantityFlag::mask_from_flags(mqflags);
+       meaning->mq = static_cast<sr_mq>(mq->id());
+       meaning->unit = static_cast<sr_unit>(unit->id());
+       meaning->mqflags = static_cast<sr_mqflag>(QuantityFlag::mask_from_flags(mqflags));
        analog->data = data_pointer;
        auto packet = g_new(struct sr_datafeed_packet, 1);
        packet->type = SR_DF_ANALOG;
@@ -375,23 +368,24 @@ shared_ptr<Input> Context::open_stream(string header)
                new Input(shared_from_this(), input), Input::Deleter());
 }
 
-map<string, string> Context::serials(shared_ptr<Driver> driver)
+map<string, string> Context::serials(shared_ptr<Driver> driver) const
 {
-       GSList *serial_list = sr_serial_list(driver ? driver->_structure : NULL);
+       GSList *serial_list = sr_serial_list(driver ? driver->_structure : nullptr);
        map<string, string> serials;
 
        for (GSList *serial = serial_list; serial; serial = serial->next) {
-               struct sr_serial_port *port = (sr_serial_port *) serial->data;
+               auto *const port = static_cast<sr_serial_port *>(serial->data);
                serials[string(port->name)] = string(port->description);
        }
 
-       g_slist_free_full(serial_list, (GDestroyNotify)sr_serial_free);
+       g_slist_free_full(serial_list,
+               reinterpret_cast<GDestroyNotify>(&sr_serial_free));
        return serials;
 }
 
 Driver::Driver(struct sr_dev_driver *structure) :
-       ParentOwned(structure),
-       Configurable(structure, NULL, NULL),
+       Configurable(structure, nullptr, nullptr),
+       _structure(structure),
        _initialized(false)
 {
 }
@@ -400,12 +394,12 @@ Driver::~Driver()
 {
 }
 
-string Driver::name()
+string Driver::name() const
 {
        return valid_string(_structure->name);
 }
 
-string Driver::long_name()
+string Driver::long_name() const
 {
        return valid_string(_structure->longname);
 }
@@ -421,7 +415,7 @@ vector<shared_ptr<HardwareDevice>> Driver::scan(
        }
 
        /* Translate scan options to GSList of struct sr_config pointers. */
-       GSList *option_list = NULL;
+       GSList *option_list = nullptr;
        for (auto entry : options)
        {
                auto key = entry.first;
@@ -443,7 +437,7 @@ vector<shared_ptr<HardwareDevice>> Driver::scan(
        vector<shared_ptr<HardwareDevice>> result;
        for (GSList *device = device_list; device; device = device->next)
        {
-               auto sdi = (struct sr_dev_inst *) device->data;
+               auto *const sdi = static_cast<struct sr_dev_inst *>(device->data);
                result.push_back(shared_ptr<HardwareDevice>(
                        new HardwareDevice(shared_from_this(), sdi),
                        HardwareDevice::Deleter()));
@@ -469,7 +463,7 @@ Configurable::~Configurable()
 {
 }
 
-Glib::VariantBase Configurable::config_get(const ConfigKey *key)
+Glib::VariantBase Configurable::config_get(const ConfigKey *key) const
 {
        GVariant *data;
        check(sr_config_get(
@@ -485,7 +479,7 @@ void Configurable::config_set(const ConfigKey *key, const Glib::VariantBase &val
                key->id(), const_cast<GVariant*>(value.gobj())));
 }
 
-Glib::VariantContainerBase Configurable::config_list(const ConfigKey *key)
+Glib::VariantContainerBase Configurable::config_list(const ConfigKey *key) const
 {
        GVariant *data;
        check(sr_config_list(
@@ -505,8 +499,8 @@ map<const ConfigKey *, set<Capability>> Configurable::config_keys(const ConfigKe
                config_driver, config_sdi, config_channel_group,
                key->id(), &gvar_opts));
 
-       opts = (const uint32_t *) g_variant_get_fixed_array(
-               gvar_opts, &num_opts, sizeof(uint32_t));
+       opts = static_cast<const uint32_t *>(g_variant_get_fixed_array(
+               gvar_opts, &num_opts, sizeof(uint32_t)));
 
        for (gsize i = 0; i < num_opts; i++)
        {
@@ -527,7 +521,7 @@ map<const ConfigKey *, set<Capability>> Configurable::config_keys(const ConfigKe
 }
 
 bool Configurable::config_check(const ConfigKey *key,
-       const ConfigKey *index_key)
+       const ConfigKey *index_key) const
 {
        GVariant *gvar_opts;
        gsize num_opts;
@@ -537,12 +531,12 @@ bool Configurable::config_check(const ConfigKey *key,
                        index_key->id(), &gvar_opts) != SR_OK)
                return false;
 
-       opts = (const uint32_t *) g_variant_get_fixed_array(
-               gvar_opts, &num_opts, sizeof(uint32_t));
+       opts = static_cast<const uint32_t *>(g_variant_get_fixed_array(
+               gvar_opts, &num_opts, sizeof(uint32_t)));
 
        for (gsize i = 0; i < num_opts; i++)
        {
-               if ((opts[i] & SR_CONF_MASK) == (uint32_t) key->id())
+               if ((opts[i] & SR_CONF_MASK) == unsigned(key->id()))
                {
                        g_variant_unref(gvar_opts);
                        return true;
@@ -555,18 +549,18 @@ bool Configurable::config_check(const ConfigKey *key,
 }
 
 Device::Device(struct sr_dev_inst *structure) :
-       Configurable(sr_dev_inst_driver_get(structure), structure, NULL),
+       Configurable(sr_dev_inst_driver_get(structure), structure, nullptr),
        _structure(structure)
 {
        for (GSList *entry = sr_dev_inst_channels_get(structure); entry; entry = entry->next)
        {
-               auto channel = (struct sr_channel *) entry->data;
+               auto *const channel = static_cast<struct sr_channel *>(entry->data);
                _channels[channel] = new Channel(channel);
        }
 
        for (GSList *entry = sr_dev_inst_channel_groups_get(structure); entry; entry = entry->next)
        {
-               auto group = (struct sr_channel_group *) entry->data;
+               auto *const group = static_cast<struct sr_channel_group *>(entry->data);
                _channel_groups[group->name] = new ChannelGroup(this, group);
        }
 }
@@ -579,27 +573,27 @@ Device::~Device()
                delete entry.second;
 }
 
-string Device::vendor()
+string Device::vendor() const
 {
        return valid_string(sr_dev_inst_vendor_get(_structure));
 }
 
-string Device::model()
+string Device::model() const
 {
        return valid_string(sr_dev_inst_model_get(_structure));
 }
 
-string Device::version()
+string Device::version() const
 {
        return valid_string(sr_dev_inst_version_get(_structure));
 }
 
-string Device::serial_number()
+string Device::serial_number() const
 {
        return valid_string(sr_dev_inst_sernum_get(_structure));
 }
 
-string Device::connection_id()
+string Device::connection_id() const
 {
        return valid_string(sr_dev_inst_connid_get(_structure));
 }
@@ -607,16 +601,16 @@ string Device::connection_id()
 vector<shared_ptr<Channel>> Device::channels()
 {
        vector<shared_ptr<Channel>> result;
-       for (auto channel = sr_dev_inst_channels_get(_structure); channel; channel = channel->next)
-               result.push_back(
-                       _channels[(struct sr_channel *) channel->data]->get_shared_pointer(
-                               get_shared_from_this()));
+       for (auto channel = sr_dev_inst_channels_get(_structure); channel; channel = channel->next) {
+               auto *const ch = static_cast<struct sr_channel *>(channel->data);
+               result.push_back(_channels[ch]->share_owned_by(get_shared_from_this()));
+       }
        return result;
 }
 
 shared_ptr<Channel> Device::get_channel(struct sr_channel *ptr)
 {
-       return _channels[ptr]->get_shared_pointer(get_shared_from_this());
+       return _channels[ptr]->share_owned_by(get_shared_from_this());
 }
 
 map<string, shared_ptr<ChannelGroup>>
@@ -627,7 +621,7 @@ Device::channel_groups()
        {
                auto name = entry.first;
                auto channel_group = entry.second;
-               result[name] = channel_group->get_shared_pointer(get_shared_from_this());
+               result[name] = channel_group->share_owned_by(get_shared_from_this());
        }
        return result;
 }
@@ -644,7 +638,6 @@ void Device::close()
 
 HardwareDevice::HardwareDevice(shared_ptr<Driver> driver,
                struct sr_dev_inst *structure) :
-       UserOwned(structure),
        Device(structure),
        _driver(move(driver))
 {
@@ -665,9 +658,8 @@ shared_ptr<Driver> HardwareDevice::driver()
 }
 
 UserDevice::UserDevice(string vendor, string model, string version) :
-       UserOwned(sr_dev_inst_user_new(
-               vendor.c_str(), model.c_str(), version.c_str())),
-       Device(UserOwned::_structure)
+       Device(sr_dev_inst_user_new(
+               vendor.c_str(), model.c_str(), version.c_str()))
 {
 }
 
@@ -685,15 +677,14 @@ shared_ptr<Channel> UserDevice::add_channel(unsigned int index,
 {
        check(sr_dev_inst_channel_add(Device::_structure,
                index, type->id(), name.c_str()));
-       struct sr_channel *structure = (struct sr_channel *)
-                       g_slist_last(sr_dev_inst_channels_get(Device::_structure))->data;
-       Channel *channel = new Channel(structure);
-       _channels[structure] = channel;
-       return get_channel(structure);
+       GSList *const last = g_slist_last(sr_dev_inst_channels_get(Device::_structure));
+       auto *const ch = static_cast<struct sr_channel *>(last->data);
+       _channels[ch] = new Channel(ch);
+       return get_channel(ch);
 }
 
 Channel::Channel(struct sr_channel *structure) :
-       ParentOwned(structure),
+       _structure(structure),
        _type(ChannelType::get(_structure->type))
 {
 }
@@ -702,7 +693,7 @@ Channel::~Channel()
 {
 }
 
-string Channel::name()
+string Channel::name() const
 {
        return valid_string(_structure->name);
 }
@@ -712,12 +703,12 @@ void Channel::set_name(string name)
        check(sr_dev_channel_name_set(_structure, name.c_str()));
 }
 
-const ChannelType *Channel::type()
+const ChannelType *Channel::type() const
 {
        return ChannelType::get(_structure->type);
 }
 
-bool Channel::enabled()
+bool Channel::enabled() const
 {
        return _structure->enabled;
 }
@@ -727,44 +718,45 @@ void Channel::set_enabled(bool value)
        check(sr_dev_channel_enable(_structure, value));
 }
 
-unsigned int Channel::index()
+unsigned int Channel::index() const
 {
        return _structure->index;
 }
 
 ChannelGroup::ChannelGroup(Device *device,
                struct sr_channel_group *structure) :
-       ParentOwned(structure),
        Configurable(sr_dev_inst_driver_get(device->_structure), device->_structure, structure)
 {
-       for (GSList *entry = structure->channels; entry; entry = entry->next)
-               _channels.push_back(device->_channels[(struct sr_channel *)entry->data]);
+       for (GSList *entry = config_channel_group->channels; entry; entry = entry->next) {
+               auto *const ch = static_cast<struct sr_channel *>(entry->data);
+               _channels.push_back(device->_channels[ch]);
+       }
 }
 
 ChannelGroup::~ChannelGroup()
 {
 }
 
-string ChannelGroup::name()
+string ChannelGroup::name() const
 {
-       return valid_string(_structure->name);
+       return valid_string(config_channel_group->name);
 }
 
 vector<shared_ptr<Channel>> ChannelGroup::channels()
 {
        vector<shared_ptr<Channel>> result;
        for (auto channel : _channels)
-               result.push_back(channel->get_shared_pointer(_parent));
+               result.push_back(channel->share_owned_by(_parent));
        return result;
 }
 
 Trigger::Trigger(shared_ptr<Context> context, string name) : 
-       UserOwned(sr_trigger_new(name.c_str())),
+       _structure(sr_trigger_new(name.c_str())),
        _context(move(context))
 {
        for (auto stage = _structure->stages; stage; stage = stage->next)
                _stages.push_back(
-                       new TriggerStage((struct sr_trigger_stage *) stage->data));
+                       new TriggerStage(static_cast<struct sr_trigger_stage *>(stage->data)));
 }
 
 Trigger::~Trigger()
@@ -775,7 +767,7 @@ Trigger::~Trigger()
        sr_trigger_free(_structure);
 }
 
-string Trigger::name()
+string Trigger::name() const
 {
        return _structure->name;
 }
@@ -784,7 +776,7 @@ vector<shared_ptr<TriggerStage>> Trigger::stages()
 {
        vector<shared_ptr<TriggerStage>> result;
        for (auto stage : _stages)
-               result.push_back(stage->get_shared_pointer(this));
+               result.push_back(stage->share_owned_by(shared_from_this()));
        return result;
 }
 
@@ -792,11 +784,11 @@ shared_ptr<TriggerStage> Trigger::add_stage()
 {
        auto stage = new TriggerStage(sr_trigger_stage_add(_structure));
        _stages.push_back(stage);
-       return stage->get_shared_pointer(this);
+       return stage->share_owned_by(shared_from_this());
 }
 
-TriggerStage::TriggerStage(struct sr_trigger_stage *structure) : 
-       ParentOwned(structure)
+TriggerStage::TriggerStage(struct sr_trigger_stage *structure) :
+       _structure(structure)
 {
 }
 
@@ -806,7 +798,7 @@ TriggerStage::~TriggerStage()
                delete match;
 }
        
-int TriggerStage::number()
+int TriggerStage::number() const
 {
        return _structure->stage;
 }
@@ -815,7 +807,7 @@ vector<shared_ptr<TriggerMatch>> TriggerStage::matches()
 {
        vector<shared_ptr<TriggerMatch>> result;
        for (auto match : _matches)
-               result.push_back(match->get_shared_pointer(this));
+               result.push_back(match->share_owned_by(shared_from_this()));
        return result;
 }
 
@@ -824,9 +816,10 @@ void TriggerStage::add_match(shared_ptr<Channel> channel,
 {
        check(sr_trigger_match_add(_structure,
                channel->_structure, type->id(), value));
+       GSList *const last = g_slist_last(_structure->matches);
        _matches.push_back(new TriggerMatch(
-               (struct sr_trigger_match *) g_slist_last(
-                       _structure->matches)->data, move(channel)));
+               static_cast<struct sr_trigger_match *>(last->data),
+               move(channel)));
 }
 
 void TriggerStage::add_match(shared_ptr<Channel> channel,
@@ -837,7 +830,7 @@ void TriggerStage::add_match(shared_ptr<Channel> channel,
 
 TriggerMatch::TriggerMatch(struct sr_trigger_match *structure,
                shared_ptr<Channel> channel) :
-       ParentOwned(structure),
+       _structure(structure),
        _channel(move(channel))
 {
 }
@@ -851,12 +844,12 @@ shared_ptr<Channel> TriggerMatch::channel()
        return _channel;
 }
 
-const TriggerMatchType *TriggerMatch::type()
+const TriggerMatchType *TriggerMatch::type() const
 {
        return TriggerMatchType::get(_structure->match);
 }
 
-float TriggerMatch::value()
+float TriggerMatch::value() const
 {
        return _structure->value;
 }
@@ -877,7 +870,6 @@ void DatafeedCallbackData::run(const struct sr_dev_inst *sdi,
 }
 
 SessionDevice::SessionDevice(struct sr_dev_inst *structure) :
-       ParentOwned(structure),
        Device(structure)
 {
 }
@@ -892,7 +884,7 @@ shared_ptr<Device> SessionDevice::get_shared_from_this()
 }
 
 Session::Session(shared_ptr<Context> context) :
-       UserOwned(_structure),
+       _structure(nullptr),
        _context(move(context))
 {
        check(sr_session_new(_context->_structure, &_structure));
@@ -900,16 +892,15 @@ Session::Session(shared_ptr<Context> context) :
 }
 
 Session::Session(shared_ptr<Context> context, string filename) :
-       UserOwned(_structure),
+       _structure(nullptr),
        _context(move(context)),
        _filename(move(filename))
 {
        check(sr_session_load(_context->_structure, _filename.c_str(), &_structure));
        GSList *dev_list;
        check(sr_session_dev_list(_structure, &dev_list));
-       for (GSList *dev = dev_list; dev; dev = dev->next)
-       {
-               auto sdi = (struct sr_dev_inst *) dev->data;
+       for (GSList *dev = dev_list; dev; dev = dev->next) {
+               auto *const sdi = static_cast<struct sr_dev_inst *>(dev->data);
                _owned_devices[sdi] = new SessionDevice(sdi);
        }
        _context->_session = this;
@@ -930,7 +921,7 @@ shared_ptr<Device> Session::get_device(const struct sr_dev_inst *sdi)
 {
        if (_owned_devices.count(sdi))
                return static_pointer_cast<Device>(
-                       _owned_devices[sdi]->get_shared_pointer(this));
+                       _owned_devices[sdi]->share_owned_by(shared_from_this()));
        else if (_other_devices.count(sdi))
                return _other_devices[sdi];
        else
@@ -949,9 +940,8 @@ vector<shared_ptr<Device>> Session::devices()
        GSList *dev_list;
        check(sr_session_dev_list(_structure, &dev_list));
        vector<shared_ptr<Device>> result;
-       for (GSList *dev = dev_list; dev; dev = dev->next)
-       {
-               auto sdi = (struct sr_dev_inst *) dev->data;
+       for (GSList *dev = dev_list; dev; dev = dev->next) {
+               auto *const sdi = static_cast<struct sr_dev_inst *>(dev->data);
                result.push_back(get_device(sdi));
        }
        return result;
@@ -986,7 +976,7 @@ bool Session::is_running() const
        return (ret != 0);
 }
 
-static void session_stopped_callback(void *data)
+static void session_stopped_callback(void *data) noexcept
 {
        auto *const callback = static_cast<SessionStoppedCallback*>(data);
        (*callback)();
@@ -1004,12 +994,12 @@ void Session::set_stopped_callback(SessionStoppedCallback callback)
 }
 
 static void datafeed_callback(const struct sr_dev_inst *sdi,
-       const struct sr_datafeed_packet *pkt, void *cb_data)
+       const struct sr_datafeed_packet *pkt, void *cb_data) noexcept
 {
        auto callback = static_cast<DatafeedCallbackData *>(cb_data);
        callback->run(sdi, pkt);
 }
-       
+
 void Session::add_datafeed_callback(DatafeedCallbackFunction callback)
 {
        auto cb_data = new DatafeedCallbackData(this, move(callback));
@@ -1035,13 +1025,13 @@ void Session::set_trigger(shared_ptr<Trigger> trigger)
 {
        if (!trigger)
                // Set NULL trigger, i.e. remove any trigger from the session.
-               check(sr_session_trigger_set(_structure, NULL));
+               check(sr_session_trigger_set(_structure, nullptr));
        else
                check(sr_session_trigger_set(_structure, trigger->_structure));
        _trigger = move(trigger);
 }
 
-string Session::filename()
+string Session::filename() const
 {
        return _filename;
 }
@@ -1053,7 +1043,7 @@ shared_ptr<Context> Session::context()
 
 Packet::Packet(shared_ptr<Device> device,
        const struct sr_datafeed_packet *structure) :
-       UserOwned(structure),
+       _structure(structure),
        _device(move(device))
 {
        switch (structure->type)
@@ -1090,7 +1080,7 @@ Packet::~Packet()
                delete _payload;
 }
 
-const PacketType *Packet::type()
+const PacketType *Packet::type() const
 {
        return PacketType::get(_structure->type);
 }
@@ -1098,7 +1088,7 @@ const PacketType *Packet::type()
 shared_ptr<PacketPayload> Packet::payload()
 {
        if (_payload)
-               return _payload->get_shared_pointer(this);
+               return _payload->share_owned_by(shared_from_this());
        else
                throw Error(SR_ERR_NA);
 }
@@ -1112,8 +1102,8 @@ PacketPayload::~PacketPayload()
 }
 
 Header::Header(const struct sr_datafeed_header *structure) :
-       ParentOwned(structure),
-       PacketPayload()
+       PacketPayload(),
+       _structure(structure)
 {
 }
 
@@ -1121,18 +1111,18 @@ Header::~Header()
 {
 }
 
-shared_ptr<PacketPayload> Header::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Header::share_owned_by(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
-               ParentOwned::get_shared_pointer(_parent));
+               ParentOwned::share_owned_by(_parent));
 }
 
-int Header::feed_version()
+int Header::feed_version() const
 {
        return _structure->feed_version;
 }
 
-Glib::TimeVal Header::start_time()
+Glib::TimeVal Header::start_time() const
 {
        return Glib::TimeVal(
                _structure->starttime.tv_sec,
@@ -1140,8 +1130,8 @@ Glib::TimeVal Header::start_time()
 }
 
 Meta::Meta(const struct sr_datafeed_meta *structure) :
-       ParentOwned(structure),
-       PacketPayload()
+       PacketPayload(),
+       _structure(structure)
 {
 }
 
@@ -1149,26 +1139,25 @@ Meta::~Meta()
 {
 }
 
-shared_ptr<PacketPayload> Meta::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Meta::share_owned_by(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
-               ParentOwned::get_shared_pointer(_parent));
+               ParentOwned::share_owned_by(_parent));
 }
 
-map<const ConfigKey *, Glib::VariantBase> Meta::config()
+map<const ConfigKey *, Glib::VariantBase> Meta::config() const
 {
        map<const ConfigKey *, Glib::VariantBase> result;
-       for (auto l = _structure->config; l; l = l->next)
-       {
-               auto config = (struct sr_config *) l->data;
+       for (auto l = _structure->config; l; l = l->next) {
+               auto *const config = static_cast<struct sr_config *>(l->data);
                result[ConfigKey::get(config->key)] = Glib::VariantBase(config->data);
        }
        return result;
 }
 
 Logic::Logic(const struct sr_datafeed_logic *structure) :
-       ParentOwned(structure),
-       PacketPayload()
+       PacketPayload(),
+       _structure(structure)
 {
 }
 
@@ -1176,10 +1165,10 @@ Logic::~Logic()
 {
 }
 
-shared_ptr<PacketPayload> Logic::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Logic::share_owned_by(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
-               ParentOwned::get_shared_pointer(_parent));
+               ParentOwned::share_owned_by(_parent));
 }
 
 void *Logic::data_pointer()
@@ -1187,19 +1176,19 @@ void *Logic::data_pointer()
        return _structure->data;
 }
 
-size_t Logic::data_length()
+size_t Logic::data_length() const
 {
        return _structure->length;
 }
 
-unsigned int Logic::unit_size()
+unsigned int Logic::unit_size() const
 {
        return _structure->unitsize;
 }
 
 Analog::Analog(const struct sr_datafeed_analog *structure) :
-       ParentOwned(structure),
-       PacketPayload()
+       PacketPayload(),
+       _structure(structure)
 {
 }
 
@@ -1207,10 +1196,10 @@ Analog::~Analog()
 {
 }
 
-shared_ptr<PacketPayload> Analog::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Analog::share_owned_by(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
-               ParentOwned::get_shared_pointer(_parent));
+               ParentOwned::share_owned_by(_parent));
 }
 
 void *Analog::data_pointer()
@@ -1218,7 +1207,7 @@ void *Analog::data_pointer()
        return _structure->data;
 }
 
-unsigned int Analog::num_samples()
+unsigned int Analog::num_samples() const
 {
        return _structure->num_samples;
 }
@@ -1226,29 +1215,30 @@ unsigned int Analog::num_samples()
 vector<shared_ptr<Channel>> Analog::channels()
 {
        vector<shared_ptr<Channel>> result;
-       for (auto l = _structure->meaning->channels; l; l = l->next)
-               result.push_back(_parent->_device->get_channel(
-                       (struct sr_channel *)l->data));
+       for (auto l = _structure->meaning->channels; l; l = l->next) {
+               auto *const ch = static_cast<struct sr_channel *>(l->data);
+               result.push_back(_parent->_device->get_channel(ch));
+       }
        return result;
 }
 
-const Quantity *Analog::mq()
+const Quantity *Analog::mq() const
 {
        return Quantity::get(_structure->meaning->mq);
 }
 
-const Unit *Analog::unit()
+const Unit *Analog::unit() const
 {
        return Unit::get(_structure->meaning->unit);
 }
 
-vector<const QuantityFlag *> Analog::mq_flags()
+vector<const QuantityFlag *> Analog::mq_flags() const
 {
        return QuantityFlag::flags_from_mask(_structure->meaning->mqflags);
 }
 
 InputFormat::InputFormat(const struct sr_input_module *structure) :
-       ParentOwned(structure)
+       _structure(structure)
 {
 }
 
@@ -1256,17 +1246,17 @@ InputFormat::~InputFormat()
 {
 }
 
-string InputFormat::name()
+string InputFormat::name() const
 {
        return valid_string(sr_input_id_get(_structure));
 }
 
-string InputFormat::description()
+string InputFormat::description() const
 {
        return valid_string(sr_input_description_get(_structure));
 }
 
-vector<string> InputFormat::extensions()
+vector<string> InputFormat::extensions() const
 {
        vector<string> exts;
        for (const char *const *e = sr_input_extensions_get(_structure);
@@ -1296,12 +1286,11 @@ shared_ptr<Input> InputFormat::create_input(
        auto input = sr_input_new(_structure, map_to_hash_variant(options));
        if (!input)
                throw Error(SR_ERR_ARG);
-       return shared_ptr<Input>(
-               new Input(_parent->shared_from_this(), input), Input::Deleter());
+       return shared_ptr<Input>(new Input(_parent, input), Input::Deleter());
 }
 
 Input::Input(shared_ptr<Context> context, const struct sr_input *structure) :
-       UserOwned(structure),
+       _structure(structure),
        _context(move(context)),
        _device(nullptr)
 {
@@ -1317,12 +1306,12 @@ shared_ptr<InputDevice> Input::device()
                _device = new InputDevice(shared_from_this(), sdi);
        }
 
-       return _device->get_shared_pointer(shared_from_this());
+       return _device->share_owned_by(shared_from_this());
 }
 
 void Input::send(void *data, size_t length)
 {
-       auto gstr = g_string_new_len((gchar *)data, length);
+       auto gstr = g_string_new_len(static_cast<char *>(data), length);
        auto ret = sr_input_send(_structure, gstr);
        g_string_free(gstr, false);
        check(ret);
@@ -1342,7 +1331,6 @@ Input::~Input()
 
 InputDevice::InputDevice(shared_ptr<Input> input,
                struct sr_dev_inst *structure) :
-       ParentOwned(structure),
        Device(structure),
        _input(move(input))
 {
@@ -1359,7 +1347,7 @@ shared_ptr<Device> InputDevice::get_shared_from_this()
 
 Option::Option(const struct sr_option *structure,
                shared_ptr<const struct sr_option *> structure_array) :
-       UserOwned(structure),
+       _structure(structure),
        _structure_array(move(structure_array))
 {
 }
@@ -1368,36 +1356,38 @@ Option::~Option()
 {
 }
 
-string Option::id()
+string Option::id() const
 {
        return valid_string(_structure->id);
 }
 
-string Option::name()
+string Option::name() const
 {
        return valid_string(_structure->name);
 }
 
-string Option::description()
+string Option::description() const
 {
        return valid_string(_structure->desc);
 }
 
-Glib::VariantBase Option::default_value()
+Glib::VariantBase Option::default_value() const
 {
        return Glib::VariantBase(_structure->def, true);
 }
 
-vector<Glib::VariantBase> Option::values()
+vector<Glib::VariantBase> Option::values() const
 {
        vector<Glib::VariantBase> result;
-       for (auto l = _structure->values; l; l = l->next)
-               result.push_back(Glib::VariantBase((GVariant *) l->data, true));
+       for (auto l = _structure->values; l; l = l->next) {
+               auto *const var = static_cast<GVariant *>(l->data);
+               result.push_back(Glib::VariantBase(var, true));
+       }
        return result;
 }
 
 OutputFormat::OutputFormat(const struct sr_output_module *structure) :
-       ParentOwned(structure)
+       _structure(structure)
 {
 }
 
@@ -1405,17 +1395,17 @@ OutputFormat::~OutputFormat()
 {
 }
 
-string OutputFormat::name()
+string OutputFormat::name() const
 {
        return valid_string(sr_output_id_get(_structure));
 }
 
-string OutputFormat::description()
+string OutputFormat::description() const
 {
        return valid_string(sr_output_description_get(_structure));
 }
 
-vector<string> OutputFormat::extensions()
+vector<string> OutputFormat::extensions() const
 {
        vector<string> exts;
        for (const char *const *e = sr_output_extensions_get(_structure);
@@ -1455,15 +1445,15 @@ shared_ptr<Output> OutputFormat::create_output(string filename,
                Output::Deleter());
 }
 
-bool OutputFormat::test_flag(const OutputFlag *flag)
+bool OutputFormat::test_flag(const OutputFlag *flag) const
 {
        return sr_output_test_flag(_structure, flag->id());
 }
 
 Output::Output(shared_ptr<OutputFormat> format,
                shared_ptr<Device> device, const map<string, Glib::VariantBase> &options) :
-       UserOwned(sr_output_new(format->_structure,
-               map_to_hash_variant(options), device->_structure, NULL)),
+       _structure(sr_output_new(format->_structure,
+               map_to_hash_variant(options), device->_structure, nullptr)),
        _format(move(format)),
        _device(move(device)),
        _options(options)
@@ -1472,7 +1462,7 @@ Output::Output(shared_ptr<OutputFormat> format,
 
 Output::Output(string filename, shared_ptr<OutputFormat> format,
                shared_ptr<Device> device, const map<string, Glib::VariantBase> &options) :
-       UserOwned(sr_output_new(format->_structure,
+       _structure(sr_output_new(format->_structure,
                map_to_hash_variant(options), device->_structure, filename.c_str())),
        _format(move(format)),
        _device(move(device)),